Sample records for release earthquake prediction
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Moment-ration imaging of seismic regions for earthquake prediction
Lomnitz, Cinna
1993-10-01
An algorithm for predicting large earthquakes is proposed. The reciprocal ratio (mri) of the residual seismic moment to the total moment release in a region is used for imaging seismic moment precursors. Peaks in mri predict recent major earthquakes, including the 1985 Michoacan, 1985 central Chile, and 1992 Eureka, California earthquakes.
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Yin, X. C.; Mora, P.; Peng, K.; Wang, Y. C.; Weatherley, D.
The main idea of the Load-Unload Response Ratio (LURR) is that when a system is stable, its response to loading corresponds to its response to unloading, whereas when the system is approaching an unstable state, the response to loading and unloading becomes quite different. High LURR values and observations of Accelerating Moment/Energy Release (AMR/AER) prior to large earthquakes have led different research groups to suggest intermediate-term earthquake prediction is possible and imply that the LURR and AMR/AER observations may have a similar physical origin. To study this possibility, we conducted a retrospective examination of several Australian and Chinese earthquakes with magnitudes ranging from 5.0 to 7.9, including Australia's deadly Newcastle earthquake and the devastating Tangshan earthquake. Both LURR values and best-fit power-law time-to-failure functions were computed using data within a range of distances from the epicenter. Like the best-fit power-law fits in AMR/AER, the LURR value was optimal using data within a certain epicentral distance implying a critical region for LURR. Furthermore, LURR critical region size scales with mainshock magnitude and is similar to the AMR/AER critical region size. These results suggest a common physical origin for both the AMR/AER and LURR observations. Further research may provide clues that yield an understanding of this mechanism and help lead to a solid foundation for intermediate-term earthquake prediction.
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International Nuclear Information System (INIS)
Ward, P.L.
1978-01-01
The state of the art of earthquake prediction is summarized, the possible responses to such prediction are examined, and some needs in the present prediction program and in research related to use of this new technology are reviewed. Three basic aspects of earthquake prediction are discussed: location of the areas where large earthquakes are most likely to occur, observation within these areas of measurable changes (earthquake precursors) and determination of the area and time over which the earthquake will occur, and development of models of the earthquake source in order to interpret the precursors reliably. 6 figures
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Failures and suggestions in Earthquake forecasting and prediction
Sacks, S. I.
2013-12-01
Seismologists have had poor success in earthquake prediction. However, wide ranging observations from earlier great earthquakes show that precursory data can exist. In particular, two aspects seem promising. In agreement with simple physical modeling, b-values decrease in highly loaded fault zones for years before failure. Potentially more usefully, in high stress regions, breakdown of dilatant patches leading to failure can yield expelled water-related observations. The volume increase (dilatancy) caused by high shear stresses decreases the pore pressure. Eventually, water flows back in restoring the pore pressure, promoting failure and expelling the extra water. Of course, in a generally stressed region there may be many small patches that fail, such as observed before the 1975 Haicheng earthquake. Only a few days before the major event will most of the dilatancy breakdown occur in the fault zone itself such as for the Tangshan, 1976 destructive event. Observations of 'water release' effects have been observed before the 1923 great Kanto earthquake, the 1984 Yamasaki event, the 1975 Haicheng and the 1976 Tangshan earthquakes and also the 1995 Kobe earthquake. While there are obvious difficulties in water release observations, not least because there is currently no observational network anywhere, historical data does suggest some promise if we broaden our approach to this difficult subject.
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Geophysical Anomalies and Earthquake Prediction
Jackson, D. D.
2008-12-01
Finding anomalies is easy. Predicting earthquakes convincingly from such anomalies is far from easy. Why? Why have so many beautiful geophysical abnormalities not led to successful prediction strategies? What is earthquake prediction? By my definition it is convincing information that an earthquake of specified size is temporarily much more likely than usual in a specific region for a specified time interval. We know a lot about normal earthquake behavior, including locations where earthquake rates are higher than elsewhere, with estimable rates and size distributions. We know that earthquakes have power law size distributions over large areas, that they cluster in time and space, and that aftershocks follow with power-law dependence on time. These relationships justify prudent protective measures and scientific investigation. Earthquake prediction would justify exceptional temporary measures well beyond those normal prudent actions. Convincing earthquake prediction would result from methods that have demonstrated many successes with few false alarms. Predicting earthquakes convincingly is difficult for several profound reasons. First, earthquakes start in tiny volumes at inaccessible depth. The power law size dependence means that tiny unobservable ones are frequent almost everywhere and occasionally grow to larger size. Thus prediction of important earthquakes is not about nucleation, but about identifying the conditions for growth. Second, earthquakes are complex. They derive their energy from stress, which is perniciously hard to estimate or model because it is nearly singular at the margins of cracks and faults. Physical properties vary from place to place, so the preparatory processes certainly vary as well. Thus establishing the needed track record for validation is very difficult, especially for large events with immense interval times in any one location. Third, the anomalies are generally complex as well. Electromagnetic anomalies in particular require
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Earthquake predictions using seismic velocity ratios
Sherburne, R. W.
1979-01-01
Since the beginning of modern seismology, seismologists have contemplated predicting earthquakes. The usefulness of earthquake predictions to the reduction of human and economic losses and the value of long-range earthquake prediction to planning is obvious. Not as clear are the long-range economic and social impacts of earthquake prediction to a speicifc area. The general consensus of opinion among scientists and government officials, however, is that the quest of earthquake prediction is a worthwhile goal and should be prusued with a sense of urgency.
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Earthquake prediction by Kina Method
International Nuclear Information System (INIS)
Kianoosh, H.; Keypour, H.; Naderzadeh, A.; Motlagh, H.F.
2005-01-01
Earthquake prediction has been one of the earliest desires of the man. Scientists have worked hard to predict earthquakes for a long time. The results of these efforts can generally be divided into two methods of prediction: 1) Statistical Method, and 2) Empirical Method. In the first method, earthquakes are predicted using statistics and probabilities, while the second method utilizes variety of precursors for earthquake prediction. The latter method is time consuming and more costly. However, the result of neither method has fully satisfied the man up to now. In this paper a new method entitled 'Kiana Method' is introduced for earthquake prediction. This method offers more accurate results yet lower cost comparing to other conventional methods. In Kiana method the electrical and magnetic precursors are measured in an area. Then, the time and the magnitude of an earthquake in the future is calculated using electrical, and in particular, electrical capacitors formulas. In this method, by daily measurement of electrical resistance in an area we make clear that the area is capable of earthquake occurrence in the future or not. If the result shows a positive sign, then the occurrence time and the magnitude can be estimated by the measured quantities. This paper explains the procedure and details of this prediction method. (authors)
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Elastic energy release in great earthquakes and eruptions
Directory of Open Access Journals (Sweden)
Agust eGudmundsson
2014-05-01
Full Text Available The sizes of earthquakes are measured using well-defined, measurable quantities such as seismic moment and released (transformed elastic energy. No similar measures exist for the sizes of volcanic eruptions, making it difficult to compare the energies released in earthquakes and eruptions. Here I provide a new measure of the elastic energy (the potential mechanical energy associated with magma chamber rupture and contraction (shrinkage during an eruption. For earthquakes and eruptions, elastic energy derives from two sources: (1 the strain energy stored in the volcano/fault zone before rupture, and (2 the external applied load (force, pressure, stress, displacement on the volcano/fault zone. From thermodynamic considerations it follows that the elastic energy released or transformed (dU during an eruption is directly proportional to the excess pressure (pe in the magma chamber at the time of rupture multiplied by the volume decrease (-dVc of the chamber, so that . This formula can be used as a basis for a new eruption magnitude scale, based on elastic energy released, which can be related to the moment-magnitude scale for earthquakes. For very large eruptions (>100 km3, the volume of the feeder-dike is negligible, so that the decrease in chamber volume during an eruption corresponds roughly to the associated volume of erupted materials , so that the elastic energy is . Using a typical excess pressures of 5 MPa, it is shown that the largest known eruptions on Earth, such as the explosive La Garita Caldera eruption (27-28 million years ago and largest single (effusive Colombia River basalt lava flows (15-16 million years ago, both of which have estimated volumes of about 5000 km3, released elastic energy of the order of 10EJ. For comparison, the seismic moment of the largest earthquake ever recorded, the M9.5 1960 Chile earthquake, is estimated at 100 ZJ and the associated elastic energy release at 10EJ.
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Collaboratory for the Study of Earthquake Predictability
Schorlemmer, D.; Jordan, T. H.; Zechar, J. D.; Gerstenberger, M. C.; Wiemer, S.; Maechling, P. J.
2006-12-01
Earthquake prediction is one of the most difficult problems in physical science and, owing to its societal implications, one of the most controversial. The study of earthquake predictability has been impeded by the lack of an adequate experimental infrastructure---the capability to conduct scientific prediction experiments under rigorous, controlled conditions and evaluate them using accepted criteria specified in advance. To remedy this deficiency, the Southern California Earthquake Center (SCEC) is working with its international partners, which include the European Union (through the Swiss Seismological Service) and New Zealand (through GNS Science), to develop a virtual, distributed laboratory with a cyberinfrastructure adequate to support a global program of research on earthquake predictability. This Collaboratory for the Study of Earthquake Predictability (CSEP) will extend the testing activities of SCEC's Working Group on Regional Earthquake Likelihood Models, from which we will present first results. CSEP will support rigorous procedures for registering prediction experiments on regional and global scales, community-endorsed standards for assessing probability-based and alarm-based predictions, access to authorized data sets and monitoring products from designated natural laboratories, and software to allow researchers to participate in prediction experiments. CSEP will encourage research on earthquake predictability by supporting an environment for scientific prediction experiments that allows the predictive skill of proposed algorithms to be rigorously compared with standardized reference methods and data sets. It will thereby reduce the controversies surrounding earthquake prediction, and it will allow the results of prediction experiments to be communicated to the scientific community, governmental agencies, and the general public in an appropriate research context.
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Rubinstein, Justin L.; Ellsworth, William L.; Chen, Kate Huihsuan; Uchida, Naoki
2012-01-01
The behavior of individual events in repeating earthquake sequences in California, Taiwan and Japan is better predicted by a model with fixed inter-event time or fixed slip than it is by the time- and slip-predictable models for earthquake occurrence. Given that repeating earthquakes are highly regular in both inter-event time and seismic moment, the time- and slip-predictable models seem ideally suited to explain their behavior. Taken together with evidence from the companion manuscript that shows similar results for laboratory experiments we conclude that the short-term predictions of the time- and slip-predictable models should be rejected in favor of earthquake models that assume either fixed slip or fixed recurrence interval. This implies that the elastic rebound model underlying the time- and slip-predictable models offers no additional value in describing earthquake behavior in an event-to-event sense, but its value in a long-term sense cannot be determined. These models likely fail because they rely on assumptions that oversimplify the earthquake cycle. We note that the time and slip of these events is predicted quite well by fixed slip and fixed recurrence models, so in some sense they are time- and slip-predictable. While fixed recurrence and slip models better predict repeating earthquake behavior than the time- and slip-predictable models, we observe a correlation between slip and the preceding recurrence time for many repeating earthquake sequences in Parkfield, California. This correlation is not found in other regions, and the sequences with the correlative slip-predictable behavior are not distinguishable from nearby earthquake sequences that do not exhibit this behavior.
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Stigma in science: the case of earthquake prediction.
Joffe, Helene; Rossetto, Tiziana; Bradley, Caroline; O'Connor, Cliodhna
2018-01-01
This paper explores how earthquake scientists conceptualise earthquake prediction, particularly given the conviction of six earthquake scientists for manslaughter (subsequently overturned) on 22 October 2012 for having given inappropriate advice to the public prior to the L'Aquila earthquake of 6 April 2009. In the first study of its kind, semi-structured interviews were conducted with 17 earthquake scientists and the transcribed interviews were analysed thematically. The scientists primarily denigrated earthquake prediction, showing strong emotive responses and distancing themselves from earthquake 'prediction' in favour of 'forecasting'. Earthquake prediction was regarded as impossible and harmful. The stigmatisation of the subject is discussed in the light of research on boundary work and stigma in science. The evaluation reveals how mitigation becomes the more favoured endeavour, creating a normative environment that disadvantages those who continue to pursue earthquake prediction research. Recommendations are made for communication with the public on earthquake risk, with a focus on how scientists portray uncertainty. © 2018 The Author(s). Disasters © Overseas Development Institute, 2018.
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Earthquake prediction in Japan and natural time analysis of seismicity
Uyeda, S.; Varotsos, P.
2011-12-01
M9 super-giant earthquake with huge tsunami devastated East Japan on 11 March, causing more than 20,000 casualties and serious damage of Fukushima nuclear plant. This earthquake was predicted neither short-term nor long-term. Seismologists were shocked because it was not even considered possible to happen at the East Japan subduction zone. However, it was not the only un-predicted earthquake. In fact, throughout several decades of the National Earthquake Prediction Project, not even a single earthquake was predicted. In reality, practically no effective research has been conducted for the most important short-term prediction. This happened because the Japanese National Project was devoted for construction of elaborate seismic networks, which was not the best way for short-term prediction. After the Kobe disaster, in order to parry the mounting criticism on their no success history, they defiantly changed their policy to "stop aiming at short-term prediction because it is impossible and concentrate resources on fundamental research", that meant to obtain "more funding for no prediction research". The public were and are not informed about this change. Obviously earthquake prediction would be possible only when reliable precursory phenomena are caught and we have insisted this would be done most likely through non-seismic means such as geochemical/hydrological and electromagnetic monitoring. Admittedly, the lack of convincing precursors for the M9 super-giant earthquake has adverse effect for us, although its epicenter was far out off shore of the range of operating monitoring systems. In this presentation, we show a new possibility of finding remarkable precursory signals, ironically, from ordinary seismological catalogs. In the frame of the new time domain termed natural time, an order parameter of seismicity, κ1, has been introduced. This is the variance of natural time kai weighted by normalised energy release at χ. In the case that Seismic Electric Signals
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Modified-Fibonacci-Dual-Lucas method for earthquake prediction
Boucouvalas, A. C.; Gkasios, M.; Tselikas, N. T.; Drakatos, G.
2015-06-01
The FDL method makes use of Fibonacci, Dual and Lucas numbers and has shown considerable success in predicting earthquake events locally as well as globally. Predicting the location of the epicenter of an earthquake is one difficult challenge the other being the timing and magnitude. One technique for predicting the onset of earthquakes is the use of cycles, and the discovery of periodicity. Part of this category is the reported FDL method. The basis of the reported FDL method is the creation of FDL future dates based on the onset date of significant earthquakes. The assumption being that each occurred earthquake discontinuity can be thought of as a generating source of FDL time series The connection between past earthquakes and future earthquakes based on FDL numbers has also been reported with sample earthquakes since 1900. Using clustering methods it has been shown that significant earthquakes (conjunct Sun, Moon opposite Sun, Moon conjunct or opposite North or South Modes. In order to test improvement of the method we used all +8R earthquakes recorded since 1900, (86 earthquakes from USGS data). We have developed the FDL numbers for each of those seeds, and examined the earthquake hit rates (for a window of 3, i.e. +-1 day of target date) and for <6.5R. The successes are counted for each one of the 86 earthquake seeds and we compare the MFDL method with the FDL method. In every case we find improvement when the starting seed date is on the planetary trigger date prior to the earthquake. We observe no improvement only when a planetary trigger coincided with the earthquake date and in this case the FDL method coincides with the MFDL. Based on the MDFL method we present the prediction method capable of predicting global events or localized earthquakes and we will discuss the accuracy of the method in as far as the prediction and location parts of the method. We show example calendar style predictions for global events as well as for the Greek region using
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Gambling scores for earthquake predictions and forecasts
Zhuang, Jiancang
2010-04-01
This paper presents a new method, namely the gambling score, for scoring the performance earthquake forecasts or predictions. Unlike most other scoring procedures that require a regular scheme of forecast and treat each earthquake equally, regardless their magnitude, this new scoring method compensates the risk that the forecaster has taken. Starting with a certain number of reputation points, once a forecaster makes a prediction or forecast, he is assumed to have betted some points of his reputation. The reference model, which plays the role of the house, determines how many reputation points the forecaster can gain if he succeeds, according to a fair rule, and also takes away the reputation points betted by the forecaster if he loses. This method is also extended to the continuous case of point process models, where the reputation points betted by the forecaster become a continuous mass on the space-time-magnitude range of interest. We also calculate the upper bound of the gambling score when the true model is a renewal process, the stress release model or the ETAS model and when the reference model is the Poisson model.
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Strong ground motion prediction using virtual earthquakes.
Denolle, M A; Dunham, E M; Prieto, G A; Beroza, G C
2014-01-24
Sedimentary basins increase the damaging effects of earthquakes by trapping and amplifying seismic waves. Simulations of seismic wave propagation in sedimentary basins capture this effect; however, there exists no method to validate these results for earthquakes that have not yet occurred. We present a new approach for ground motion prediction that uses the ambient seismic field. We apply our method to a suite of magnitude 7 scenario earthquakes on the southern San Andreas fault and compare our ground motion predictions with simulations. Both methods find strong amplification and coupling of source and structure effects, but they predict substantially different shaking patterns across the Los Angeles Basin. The virtual earthquake approach provides a new approach for predicting long-period strong ground motion.
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Quantitative Earthquake Prediction on Global and Regional Scales
International Nuclear Information System (INIS)
Kossobokov, Vladimir G.
2006-01-01
The Earth is a hierarchy of volumes of different size. Driven by planetary convection these volumes are involved into joint and relative movement. The movement is controlled by a wide variety of processes on and around the fractal mesh of boundary zones, and does produce earthquakes. This hierarchy of movable volumes composes a large non-linear dynamical system. Prediction of such a system in a sense of extrapolation of trajectory into the future is futile. However, upon coarse-graining the integral empirical regularities emerge opening possibilities of prediction in a sense of the commonly accepted consensus definition worked out in 1976 by the US National Research Council. Implications of the understanding hierarchical nature of lithosphere and its dynamics based on systematic monitoring and evidence of its unified space-energy similarity at different scales help avoiding basic errors in earthquake prediction claims. They suggest rules and recipes of adequate earthquake prediction classification, comparison and optimization. The approach has already led to the design of reproducible intermediate-term middle-range earthquake prediction technique. Its real-time testing aimed at prediction of the largest earthquakes worldwide has proved beyond any reasonable doubt the effectiveness of practical earthquake forecasting. In the first approximation, the accuracy is about 1-5 years and 5-10 times the anticipated source dimension. Further analysis allows reducing spatial uncertainty down to 1-3 source dimensions, although at a cost of additional failures-to-predict. Despite of limited accuracy a considerable damage could be prevented by timely knowledgeable use of the existing predictions and earthquake prediction strategies. The December 26, 2004 Indian Ocean Disaster seems to be the first indication that the methodology, designed for prediction of M8.0+ earthquakes can be rescaled for prediction of both smaller magnitude earthquakes (e.g., down to M5.5+ in Italy) and
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Quantitative Earthquake Prediction on Global and Regional Scales
Kossobokov, Vladimir G.
2006-03-01
The Earth is a hierarchy of volumes of different size. Driven by planetary convection these volumes are involved into joint and relative movement. The movement is controlled by a wide variety of processes on and around the fractal mesh of boundary zones, and does produce earthquakes. This hierarchy of movable volumes composes a large non-linear dynamical system. Prediction of such a system in a sense of extrapolation of trajectory into the future is futile. However, upon coarse-graining the integral empirical regularities emerge opening possibilities of prediction in a sense of the commonly accepted consensus definition worked out in 1976 by the US National Research Council. Implications of the understanding hierarchical nature of lithosphere and its dynamics based on systematic monitoring and evidence of its unified space-energy similarity at different scales help avoiding basic errors in earthquake prediction claims. They suggest rules and recipes of adequate earthquake prediction classification, comparison and optimization. The approach has already led to the design of reproducible intermediate-term middle-range earthquake prediction technique. Its real-time testing aimed at prediction of the largest earthquakes worldwide has proved beyond any reasonable doubt the effectiveness of practical earthquake forecasting. In the first approximation, the accuracy is about 1-5 years and 5-10 times the anticipated source dimension. Further analysis allows reducing spatial uncertainty down to 1-3 source dimensions, although at a cost of additional failures-to-predict. Despite of limited accuracy a considerable damage could be prevented by timely knowledgeable use of the existing predictions and earthquake prediction strategies. The December 26, 2004 Indian Ocean Disaster seems to be the first indication that the methodology, designed for prediction of M8.0+ earthquakes can be rescaled for prediction of both smaller magnitude earthquakes (e.g., down to M5.5+ in Italy) and
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Earthquake prediction the ory and its relation to precursors
International Nuclear Information System (INIS)
Negarestani, A.; Setayeshi, S.; Ghannadi-Maragheh, M.; Akasheh, B.
2001-01-01
Since we don't have enough knowledge about the Physics of earthquakes. therefore. the study of seismic precursors plays an important role in earthquake prediction. Earthquake prediction is a science which discusses about precursory phenomena during seismogenic process, and then investigates the correlation and association among them and the intrinsic relation between precursors and the seismogenic process. ar the end judges comprehensively the seismic status and finally makes earthquake prediction. There are two ways for predicting earthquake prediction. The first is to study the physics of seismogenic process and to determine the parameters in the process based on the source theories and the second way is to use seismic precursors. In this paper the theory of earthquake is reviewed. We also study theory of earthquake using models of earthquake origin, the relation between seismogenic process and various accompanying precursory phenomena. The earthquake prediction is divided into three categories: long-term, medium-term and short-term. We study seismic anomalous behavior. electric field, crustal deformation, gravity. magnetism of earth. change of groundwater variation. groundwater geochemistry and change of Radon gas emission. Finally, it is concluded the there is a correlation between Radon gas emission and earthquake phenomena. Meanwhile, there are some samples from actual processing in this area
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The 2008 Wenchuan Earthquake and the Rise and Fall of Earthquake Prediction in China
Chen, Q.; Wang, K.
2009-12-01
Regardless of the future potential of earthquake prediction, it is presently impractical to rely on it to mitigate earthquake disasters. The practical approach is to strengthen the resilience of our built environment to earthquakes based on hazard assessment. But this was not common understanding in China when the M 7.9 Wenchuan earthquake struck the Sichuan Province on 12 May 2008, claiming over 80,000 lives. In China, earthquake prediction is a government-sanctioned and law-regulated measure of disaster prevention. A sudden boom of the earthquake prediction program in 1966-1976 coincided with a succession of nine M > 7 damaging earthquakes in the densely populated region of the country and the political chaos of the Cultural Revolution. It climaxed with the prediction of the 1975 Haicheng earthquake, which was due mainly to an unusually pronounced foreshock sequence and the extraordinary readiness of some local officials to issue imminent warning and evacuation order. The Haicheng prediction was a success in practice and yielded useful lessons, but the experience cannot be applied to most other earthquakes and cultural environments. Since the disastrous Tangshan earthquake in 1976 that killed over 240,000 people, there have been two opposite trends in China: decreasing confidence in prediction and increasing emphasis on regulating construction design for earthquake resilience. In 1976, most of the seismic intensity XI areas of Tangshan were literally razed to the ground, but in 2008, many buildings in the intensity XI areas of Wenchuan did not collapse. Prediction did not save life in either of these events; the difference was made by construction standards. For regular buildings, there was no seismic design in Tangshan to resist any earthquake shaking in 1976, but limited seismic design was required for the Wenchuan area in 2008. Although the construction standards were later recognized to be too low, those buildings that met the standards suffered much less
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Kossobokov, V.G.; Romashkova, L.L.; Keilis-Borok, V. I.; Healy, J.H.
1999-01-01
Algorithms M8 and MSc (i.e., the Mendocino Scenario) were used in a real-time intermediate-term research prediction of the strongest earthquakes in the Circum-Pacific seismic belt. Predictions are made by M8 first. Then, the areas of alarm are reduced by MSc at the cost that some earthquakes are missed in the second approximation of prediction. In 1992-1997, five earthquakes of magnitude 8 and above occurred in the test area: all of them were predicted by M8 and MSc identified correctly the locations of four of them. The space-time volume of the alarms is 36% and 18%, correspondingly, when estimated with a normalized product measure of empirical distribution of epicenters and uniform time. The statistical significance of the achieved results is beyond 99% both for M8 and MSc. For magnitude 7.5 + , 10 out of 19 earthquakes were predicted by M8 in 40% and five were predicted by M8-MSc in 13% of the total volume considered. This implies a significance level of 81% for M8 and 92% for M8-MSc. The lower significance levels might result from a global change in seismic regime in 1993-1996, when the rate of the largest events has doubled and all of them become exclusively normal or reversed faults. The predictions are fully reproducible; the algorithms M8 and MSc in complete formal definitions were published before we started our experiment [Keilis-Borok, V.I., Kossobokov, V.G., 1990. Premonitory activation of seismic flow: Algorithm M8, Phys. Earth and Planet. Inter. 61, 73-83; Kossobokov, V.G., Keilis-Borok, V.I., Smith, S.W., 1990. Localization of intermediate-term earthquake prediction, J. Geophys. Res., 95, 19763-19772; Healy, J.H., Kossobokov, V.G., Dewey, J.W., 1992. A test to evaluate the earthquake prediction algorithm, M8. U.S. Geol. Surv. OFR 92-401]. M8 is available from the IASPEI Software Library [Healy, J.H., Keilis-Borok, V.I., Lee, W.H.K. (Eds.), 1997. Algorithms for Earthquake Statistics and Prediction, Vol. 6. IASPEI Software Library]. ?? 1999 Elsevier
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76 FR 69761 - National Earthquake Prediction Evaluation Council (NEPEC)
2011-11-09
... DEPARTMENT OF THE INTERIOR U.S. Geological Survey National Earthquake Prediction Evaluation... 96-472, the National Earthquake Prediction Evaluation Council (NEPEC) will hold a 1\\1/2\\-day meeting.... Geological Survey on proposed earthquake predictions, on the completeness and scientific validity of the...
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76 FR 19123 - National Earthquake Prediction Evaluation Council (NEPEC)
2011-04-06
... Earthquake Prediction Evaluation Council (NEPEC) AGENCY: U.S. Geological Survey, Interior. ACTION: Notice of meeting. SUMMARY: Pursuant to Public Law 96-472, the National Earthquake Prediction Evaluation Council... proposed earthquake predictions, on the completeness and scientific validity of the available data related...
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The October 1992 Parkfield, California, earthquake prediction
Langbein, J.
1992-01-01
A magnitude 4.7 earthquake occurred near Parkfield, California, on October 20, 992, at 05:28 UTC (October 19 at 10:28 p.m. local or Pacific Daylight Time).This moderate shock, interpreted as the potential foreshock of a damaging earthquake on the San Andreas fault, triggered long-standing federal, state and local government plans to issue a public warning of an imminent magnitude 6 earthquake near Parkfield. Although the predicted earthquake did not take place, sophisticated suites of instruments deployed as part of the Parkfield Earthquake Prediction Experiment recorded valuable data associated with an unusual series of events. this article describes the geological aspects of these events, which occurred near Parkfield in October 1992. The accompnaying article, an edited version of a press conference b Richard Andrews, the Director of the California Office of Emergency Service (OES), describes governmental response to the prediction.
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Amato, A.; Cultrera, G.; Margheriti, L.; Nostro, C.; Selvaggi, G.; INGVterremoti Team
2011-12-01
A devastating earthquake had been predicted for May 11, 2011 in Rome. This prediction was never released officially by anyone, but it grew up in the Internet and was amplified by media. It was erroneously ascribed to Raffaele Bendandi, an Italian self-taught natural scientist who studied planetary motions. Indeed, around May 11, 2011, a planetary alignment was really expected and this contributed to give credibility to the earthquake prediction among people. During the previous months, INGV was overwhelmed with requests for information about this supposed prediction by Roman inhabitants and tourists. Given the considerable mediatic impact of this expected earthquake, INGV decided to organize an Open Day in its headquarter in Rome for people who wanted to learn more about the Italian seismicity and the earthquake as natural phenomenon. The Open Day was preceded by a press conference two days before, in which we talked about this prediction, we presented the Open Day, and we had a scientific discussion with journalists about the earthquake prediction and more in general on the real problem of seismic risk in Italy. About 40 journalists from newspapers, local and national tv's, press agencies and web news attended the Press Conference and hundreds of articles appeared in the following days, advertising the 11 May Open Day. The INGV opened to the public all day long (9am - 9pm) with the following program: i) meetings with INGV researchers to discuss scientific issues; ii) visits to the seismic monitoring room, open 24h/7 all year; iii) guided tours through interactive exhibitions on earthquakes and Earth's deep structure; iv) lectures on general topics from the social impact of rumors to seismic risk reduction; v) 13 new videos on channel YouTube.com/INGVterremoti to explain the earthquake process and give updates on various aspects of seismic monitoring in Italy; vi) distribution of books and brochures. Surprisingly, more than 3000 visitors came to visit INGV
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78 FR 64973 - National Earthquake Prediction Evaluation Council (NEPEC)
2013-10-30
... DEPARTMENT OF THE INTERIOR Geological Survey [GX14GG009950000] National Earthquake Prediction...: Pursuant to Public Law 96-472, the National Earthquake Prediction Evaluation Council (NEPEC) will hold a... Council shall advise the Director of the U.S. Geological Survey on proposed earthquake predictions, on the...
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Amato, A.; Arcoraci, L.; Casarotti, E.; Cultrera, G.; Di Stefano, R.; Margheriti, L.; Nostro, C.; Selvaggi, G.; May-11 Team
2012-04-01
Banner headlines in an Italian newspaper read on May 11, 2011: "Absence boom in offices: the urban legend in Rome become psychosis". This was the effect of a large-magnitude earthquake prediction in Rome for May 11, 2011. This prediction was never officially released, but it grew up in Internet and was amplified by media. It was erroneously ascribed to Raffaele Bendandi, an Italian self-taught natural scientist who studied planetary motions and related them to earthquakes. Indeed, around May 11, 2011, there was a planetary alignment and this increased the earthquake prediction credibility. Given the echo of this earthquake prediction, INGV decided to organize on May 11 (the same day the earthquake was predicted to happen) an Open Day in its headquarter in Rome to inform on the Italian seismicity and the earthquake physics. The Open Day was preceded by a press conference two days before, attended by about 40 journalists from newspapers, local and national TV's, press agencies and web news magazines. Hundreds of articles appeared in the following two days, advertising the 11 May Open Day. On May 11 the INGV headquarter was peacefully invaded by over 3,000 visitors from 9am to 9pm: families, students, civil protection groups and many journalists. The program included conferences on a wide variety of subjects (from social impact of rumors to seismic risk reduction) and distribution of books and brochures, in addition to several activities: meetings with INGV researchers to discuss scientific issues, visits to the seismic monitoring room (open 24h/7 all year), guided tours through interactive exhibitions on earthquakes and Earth's deep structure. During the same day, thirteen new videos have also been posted on our youtube/INGVterremoti channel to explain the earthquake process and hazard, and to provide real time periodic updates on seismicity in Italy. On May 11 no large earthquake happened in Italy. The initiative, built up in few weeks, had a very large feedback
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77 FR 53225 - National Earthquake Prediction Evaluation Council (NEPEC)
2012-08-31
... DEPARTMENT OF THE INTERIOR Geological Survey [USGS-GX12GG00995NP00] National Earthquake Prediction... meeting. SUMMARY: Pursuant to Public Law 96-472, the National Earthquake Prediction Evaluation Council... National Earthquake Information Center (NEIC), 1711 Illinois Avenue, Golden, Colorado 80401. The Council is...
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Four Examples of Short-Term and Imminent Prediction of Earthquakes
zeng, zuoxun; Liu, Genshen; Wu, Dabin; Sibgatulin, Victor
2014-05-01
We show here 4 examples of short-term and imminent prediction of earthquakes in China last year. They are Nima Earthquake(Ms5.2), Minxian Earthquake(Ms6.6), Nantou Earthquake (Ms6.7) and Dujiangyan Earthquake (Ms4.1) Imminent Prediction of Nima Earthquake(Ms5.2) Based on the comprehensive analysis of the prediction of Victor Sibgatulin using natural electromagnetic pulse anomalies and the prediction of Song Song and Song Kefu using observation of a precursory halo, and an observation for the locations of a degasification of the earth in the Naqu, Tibet by Zeng Zuoxun himself, the first author made a prediction for an earthquake around Ms 6 in 10 days in the area of the degasification point (31.5N, 89.0 E) at 0:54 of May 8th, 2013. He supplied another degasification point (31N, 86E) for the epicenter prediction at 8:34 of the same day. At 18:54:30 of May 15th, 2013, an earthquake of Ms5.2 occurred in the Nima County, Naqu, China. Imminent Prediction of Minxian Earthquake (Ms6.6) At 7:45 of July 22nd, 2013, an earthquake occurred at the border between Minxian and Zhangxian of Dingxi City (34.5N, 104.2E), Gansu province with magnitude of Ms6.6. We review the imminent prediction process and basis for the earthquake using the fingerprint method. 9 channels or 15 channels anomalous components - time curves can be outputted from the SW monitor for earthquake precursors. These components include geomagnetism, geoelectricity, crust stresses, resonance, crust inclination. When we compress the time axis, the outputted curves become different geometric images. The precursor images are different for earthquake in different regions. The alike or similar images correspond to earthquakes in a certain region. According to the 7-year observation of the precursor images and their corresponding earthquake, we usually get the fingerprint 6 days before the corresponding earthquakes. The magnitude prediction needs the comparison between the amplitudes of the fingerpringts from the same
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Zarola, Amit; Sil, Arjun
2018-04-01
This study presents the forecasting of time and magnitude size of the next earthquake in the northeast India, using four probability distribution models (Gamma, Lognormal, Weibull and Log-logistic) considering updated earthquake catalog of magnitude Mw ≥ 6.0 that occurred from year 1737-2015 in the study area. On the basis of past seismicity of the region, two types of conditional probabilities have been estimated using their best fit model and respective model parameters. The first conditional probability is the probability of seismic energy (e × 1020 ergs), which is expected to release in the future earthquake, exceeding a certain level of seismic energy (E × 1020 ergs). And the second conditional probability is the probability of seismic energy (a × 1020 ergs/year), which is expected to release per year, exceeding a certain level of seismic energy per year (A × 1020 ergs/year). The logarithm likelihood functions (ln L) were also estimated for all four probability distribution models. A higher value of ln L suggests a better model and a lower value shows a worse model. The time of the future earthquake is forecasted by dividing the total seismic energy expected to release in the future earthquake with the total seismic energy expected to release per year. The epicentre of recently occurred 4 January 2016 Manipur earthquake (M 6.7), 13 April 2016 Myanmar earthquake (M 6.9) and the 24 August 2016 Myanmar earthquake (M 6.8) are located in zone Z.12, zone Z.16 and zone Z.15, respectively and that are the identified seismic source zones in the study area which show that the proposed techniques and models yield good forecasting accuracy.
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75 FR 63854 - National Earthquake Prediction Evaluation Council (NEPEC) Advisory Committee
2010-10-18
... DEPARTMENT OF THE INTERIOR Geological Survey National Earthquake Prediction Evaluation Council...: Pursuant to Public Law 96-472, the National Earthquake Prediction Evaluation Council (NEPEC) will hold a 2... proposed earthquake predictions, on the completeness and scientific validity of the available data related...
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Radon observation for earthquake prediction
Energy Technology Data Exchange (ETDEWEB)
Wakita, Hiroshi [Tokyo Univ. (Japan)
1998-12-31
Systematic observation of groundwater radon for the purpose of earthquake prediction began in Japan in late 1973. Continuous observations are conducted at fixed stations using deep wells and springs. During the observation period, significant precursory changes including the 1978 Izu-Oshima-kinkai (M7.0) earthquake as well as numerous coseismic changes were observed. At the time of the 1995 Kobe (M7.2) earthquake, significant changes in chemical components, including radon dissolved in groundwater, were observed near the epicentral region. Precursory changes are presumably caused by permeability changes due to micro-fracturing in basement rock or migration of water from different sources during the preparation stage of earthquakes. Coseismic changes may be caused by seismic shaking and by changes in regional stress. Significant drops of radon concentration in groundwater have been observed after earthquakes at the KSM site. The occurrence of such drops appears to be time-dependent, and possibly reflects changes in the regional stress state of the observation area. The absence of radon drops seems to be correlated with periods of reduced regional seismic activity. Experience accumulated over the two past decades allows us to reach some conclusions: 1) changes in groundwater radon do occur prior to large earthquakes; 2) some sites are particularly sensitive to earthquake occurrence; and 3) the sensitivity changes over time. (author)
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Using remote sensing to predict earthquake impacts
Fylaktos, Asimakis; Yfantidou, Anastasia
2017-09-01
Natural hazards like earthquakes can result to enormous property damage, and human casualties in mountainous areas. Italy has always been exposed to numerous earthquakes, mostly concentrated in central and southern regions. Last year, two seismic events near Norcia (central Italy) have occurred, which led to substantial loss of life and extensive damage to properties, infrastructure and cultural heritage. This research utilizes remote sensing products and GIS software, to provide a database of information. We used both SAR images of Sentinel 1A and optical imagery of Landsat 8 to examine the differences of topography with the aid of the multi temporal monitoring technique. This technique suits for the observation of any surface deformation. This database is a cluster of information regarding the consequences of the earthquakes in groups, such as property and infrastructure damage, regional rifts, cultivation loss, landslides and surface deformations amongst others, all mapped on GIS software. Relevant organizations can implement these data in order to calculate the financial impact of these types of earthquakes. In the future, we can enrich this database including more regions and enhance the variety of its applications. For instance, we could predict the future impacts of any type of earthquake in several areas, and design a preliminarily model of emergency for immediate evacuation and quick recovery response. It is important to know how the surface moves, in particular geographical regions like Italy, Cyprus and Greece, where earthquakes are so frequent. We are not able to predict earthquakes, but using data from this research, we may assess the damage that could be caused in the future.
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Prediction of strong earthquake motions on rock surface using evolutionary process models
International Nuclear Information System (INIS)
Kameda, H.; Sugito, M.
1984-01-01
Stochastic process models are developed for prediction of strong earthquake motions for engineering design purposes. Earthquake motions with nonstationary frequency content are modeled by using the concept of evolutionary processes. Discussion is focused on the earthquake motions on bed rocks which are important for construction of nuclear power plants in seismic regions. On this basis, two earthquake motion prediction models are developed, one (EMP-IB Model) for prediction with given magnitude and epicentral distance, and the other (EMP-IIB Model) to account for the successive fault ruptures and the site location relative to the fault of great earthquakes. (Author) [pt
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A Deterministic Approach to Earthquake Prediction
Directory of Open Access Journals (Sweden)
Vittorio Sgrigna
2012-01-01
Full Text Available The paper aims at giving suggestions for a deterministic approach to investigate possible earthquake prediction and warning. A fundamental contribution can come by observations and physical modeling of earthquake precursors aiming at seeing in perspective the phenomenon earthquake within the framework of a unified theory able to explain the causes of its genesis, and the dynamics, rheology, and microphysics of its preparation, occurrence, postseismic relaxation, and interseismic phases. Studies based on combined ground and space observations of earthquake precursors are essential to address the issue. Unfortunately, up to now, what is lacking is the demonstration of a causal relationship (with explained physical processes and looking for a correlation between data gathered simultaneously and continuously by space observations and ground-based measurements. In doing this, modern and/or new methods and technologies have to be adopted to try to solve the problem. Coordinated space- and ground-based observations imply available test sites on the Earth surface to correlate ground data, collected by appropriate networks of instruments, with space ones detected on board of Low-Earth-Orbit (LEO satellites. Moreover, a new strong theoretical scientific effort is necessary to try to understand the physics of the earthquake.
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Study of Earthquake Disaster Prediction System of Langfang city Based on GIS
Huang, Meng; Zhang, Dian; Li, Pan; Zhang, YunHui; Zhang, RuoFei
2017-07-01
In this paper, according to the status of China’s need to improve the ability of earthquake disaster prevention, this paper puts forward the implementation plan of earthquake disaster prediction system of Langfang city based on GIS. Based on the GIS spatial database, coordinate transformation technology, GIS spatial analysis technology and PHP development technology, the seismic damage factor algorithm is used to predict the damage of the city under different intensity earthquake disaster conditions. The earthquake disaster prediction system of Langfang city is based on the B / S system architecture. Degree and spatial distribution and two-dimensional visualization display, comprehensive query analysis and efficient auxiliary decision-making function to determine the weak earthquake in the city and rapid warning. The system has realized the transformation of the city’s earthquake disaster reduction work from static planning to dynamic management, and improved the city’s earthquake and disaster prevention capability.
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Three Millennia of Seemingly Time-Predictable Earthquakes, Tell Ateret
Agnon, Amotz; Marco, Shmuel; Ellenblum, Ronnie
2014-05-01
Among various idealized recurrence models of large earthquakes, the "time-predictable" model has a straightforward mechanical interpretation, consistent with simple friction laws. On a time-predictable fault, the time interval between an earthquake and its predecessor is proportional to the slip during the predecessor. The alternative "slip-predictable" model states that the slip during earthquake rupture is proportional to the preceding time interval. Verifying these models requires extended records of high precision data for both timing and amount of slip. The precision of paleoearthquake data can rarely confirm or rule out predictability, and recent papers argue for either time- or slip-predictable behavior. The Ateret site, on the trace of the Dead Sea fault at the Jordan Gorge segment, offers unique precision for determining space-time patterns. Five consecutive slip events, each associated with deformed and offset sets of walls, are correlated with historical earthquakes. Two correlations are based on detailed archaeological, historical, and numismatic evidence. The other three are tentative. The offsets of three of the events are determined with high precision; the other two are not as certain. Accepting all five correlations, the fault exhibits a striking time-predictable behavior, with a long term slip rate of 3 mm/yr. However, the 30 October 1759 ~0.5 m rupture predicts a subsequent rupture along the Jordan Gorge toward the end of the last century. We speculate that earthquakres on secondary faults (the 25 November 1759 on the Rachaya branch and the 1 January 1837 on the Roum branch, both M≥7) have disrupted the 3 kyr time-predictable pattern.
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Earthquake Prediction in a Big Data World
Kossobokov, V. G.
2016-12-01
The digital revolution started just about 15 years ago has already surpassed the global information storage capacity of more than 5000 Exabytes (in optimally compressed bytes) per year. Open data in a Big Data World provides unprecedented opportunities for enhancing studies of the Earth System. However, it also opens wide avenues for deceptive associations in inter- and transdisciplinary data and for inflicted misleading predictions based on so-called "precursors". Earthquake prediction is not an easy task that implies a delicate application of statistics. So far, none of the proposed short-term precursory signals showed sufficient evidence to be used as a reliable precursor of catastrophic earthquakes. Regretfully, in many cases of seismic hazard assessment (SHA), from term-less to time-dependent (probabilistic PSHA or deterministic DSHA), and short-term earthquake forecasting (StEF), the claims of a high potential of the method are based on a flawed application of statistics and, therefore, are hardly suitable for communication to decision makers. Self-testing must be done in advance claiming prediction of hazardous areas and/or times. The necessity and possibility of applying simple tools of Earthquake Prediction Strategies, in particular, Error Diagram, introduced by G.M. Molchan in early 1990ies, and Seismic Roulette null-hypothesis as a metric of the alerted space, is evident. The set of errors, i.e. the rates of failure and of the alerted space-time volume, can be easily compared to random guessing, which comparison permits evaluating the SHA method effectiveness and determining the optimal choice of parameters in regard to a given cost-benefit function. These and other information obtained in such a simple testing may supply us with a realistic estimates of confidence and accuracy of SHA predictions and, if reliable but not necessarily perfect, with related recommendations on the level of risks for decision making in regard to engineering design, insurance
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Earthquake recurrence models fail when earthquakes fail to reset the stress field
Tormann, Thessa; Wiemer, Stefan; Hardebeck, Jeanne L.
2012-01-01
Parkfield's regularly occurring M6 mainshocks, about every 25 years, have over two decades stoked seismologists' hopes to successfully predict an earthquake of significant size. However, with the longest known inter-event time of 38 years, the latest M6 in the series (28 Sep 2004) did not conform to any of the applied forecast models, questioning once more the predictability of earthquakes in general. Our study investigates the spatial pattern of b-values along the Parkfield segment through the seismic cycle and documents a stably stressed structure. The forecasted rate of M6 earthquakes based on Parkfield's microseismicity b-values corresponds well to observed rates. We interpret the observed b-value stability in terms of the evolution of the stress field in that area: the M6 Parkfield earthquakes do not fully unload the stress on the fault, explaining why time recurrent models fail. We present the 1989 M6.9 Loma Prieta earthquake as counter example, which did release a significant portion of the stress along its fault segment and yields a substantial change in b-values.
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Some considerations regarding earthquake prediction - The case of Vrancea region -
International Nuclear Information System (INIS)
Enescu, Bogdan; Enescu, Dumitru
2000-01-01
Earthquake prediction research has been conducted for over 100 years with no obvious success. In the last year, the new modern concepts regarding the earthquake dynamics added another source of skepticism regarding the possibility of predicting earthquakes. However there are some recognizable trends, optimized in the recent years, which may give rise to more reliable and solid approaches to deal with this complex subject. In the light of these trends, emphasized by Aki, we try to analyze the new developments in the field, especially concerning the Vrancea region. (authors)
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Prediction of earthquakes: a data evaluation and exchange problem
Energy Technology Data Exchange (ETDEWEB)
Melchior, Paul
1978-11-15
Recent experiences in earthquake prediction are recalled. Precursor information seems to be available from geodetic measurements, hydrological and geochemical measurements, electric and magnetic measurements, purely seismic phenomena, and zoological phenomena; some new methods are proposed. A list of possible earthquake triggers is given. The dilatancy model is contrasted with a dry model; they seem to be equally successful. In conclusion, the space and time range of the precursors is discussed in relation to the magnitude of earthquakes. (RWR)
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Applications of the gambling score in evaluating earthquake predictions and forecasts
Zhuang, Jiancang; Zechar, Jeremy D.; Jiang, Changsheng; Console, Rodolfo; Murru, Maura; Falcone, Giuseppe
2010-05-01
This study presents a new method, namely the gambling score, for scoring the performance earthquake forecasts or predictions. Unlike most other scoring procedures that require a regular scheme of forecast and treat each earthquake equally, regardless their magnitude, this new scoring method compensates the risk that the forecaster has taken. Starting with a certain number of reputation points, once a forecaster makes a prediction or forecast, he is assumed to have betted some points of his reputation. The reference model, which plays the role of the house, determines how many reputation points the forecaster can gain if he succeeds, according to a fair rule, and also takes away the reputation points bet by the forecaster if he loses. This method is also extended to the continuous case of point process models, where the reputation points betted by the forecaster become a continuous mass on the space-time-magnitude range of interest. For discrete predictions, we apply this method to evaluate performance of Shebalin's predictions made by using the Reverse Tracing of Precursors (RTP) algorithm and of the outputs of the predictions from the Annual Consultation Meeting on Earthquake Tendency held by China Earthquake Administration. For the continuous case, we use it to compare the probability forecasts of seismicity in the Abruzzo region before and after the L'aquila earthquake based on the ETAS model and the PPE model.
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Regional distribution of released earthquake energy in northern Egypt along with Inahass area
International Nuclear Information System (INIS)
El-hemamy, S.T.; Adel, A.A. Othman
1999-01-01
A review of the seismic history of Egypt indicates sone areas of high activity concentrated along Oligocene-Miocene faults. These areas support the idea of recent activation of the Oligocene-Miocene stress cycle. There are similarities in the special distribution of recent and historical epicenters. Form the tectonic map of Egypt, distribution of Intensity and magnitude show strong activity along Nile Delta. This due to the presence of a thick layers of recent alluvial sediments. The released energy of the earthquakes are effective on the structures. The present study deals with the computed released energies of the reported earthquakes in Egypt and around Inshas area . Its effect on the urban and nuclear facilities inside Inshas site is considered. Special consideration will be given to old and new waste repository sites. The application of the determined released energy reveals that Inshas site is affected by seismic activity from five seismo-tectonic source zones, namely the Red Sea, Nile Delta, El-Faiyum, the Mediterranean Sea and the Gulf of Aqaba seismo-tectonic zones. El-Faiyum seismo-tectonic source zone has the maximum effect on the site and gave a high released energy reaching to 5.4E +2 1 erg
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Aiken, Chastity; Meng, Xiaofeng; Hardebeck, Jeanne
2018-03-01
The Geysers geothermal field is well known for being susceptible to dynamic triggering of earthquakes by large distant earthquakes, owing to the introduction of fluids for energy production. Yet, it is unknown if dynamic triggering of earthquakes is 'predictable' or whether dynamic triggering could lead to a potential hazard for energy production. In this paper, our goal is to investigate the characteristics of triggering and the physical conditions that promote triggering to determine whether or not triggering is in anyway foreseeable. We find that, at present, triggering in The Geysers is not easily 'predictable' in terms of when and where based on observable physical conditions. However, triggered earthquake magnitude positively correlates with peak imparted dynamic stress, and larger dynamic stresses tend to trigger sequences similar to mainshock-aftershock sequences. Thus, we may be able to 'predict' what size earthquakes to expect at The Geysers following a large distant earthquake.
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Signals of ENPEMF Used in Earthquake Prediction
Hao, G.; Dong, H.; Zeng, Z.; Wu, G.; Zabrodin, S. M.
2012-12-01
The signals of Earth's natural pulse electromagnetic field (ENPEMF) is a combination of the abnormal crustal magnetic field pulse affected by the earthquake, the induced field of earth's endogenous magnetic field, the induced magnetic field of the exogenous variation magnetic field, geomagnetic pulsation disturbance and other energy coupling process between sun and earth. As an instantaneous disturbance of the variation field of natural geomagnetism, ENPEMF can be used to predict earthquakes. This theory was introduced by A.A Vorobyov, who expressed a hypothesis that pulses can arise not only in the atmosphere but within the Earth's crust due to processes of tectonic-to-electric energy conversion (Vorobyov, 1970; Vorobyov, 1979). The global field time scale of ENPEMF signals has specific stability. Although the wave curves may not overlap completely at different regions, the smoothed diurnal ENPEMF patterns always exhibit the same trend per month. The feature is a good reference for observing the abnormalities of the Earth's natural magnetic field in a specific region. The frequencies of the ENPEMF signals generally locate in kilo Hz range, where frequencies within 5-25 kilo Hz range can be applied to monitor earthquakes. In Wuhan, the best observation frequency is 14.5 kilo Hz. Two special devices are placed in accordance with the S-N and W-E direction. Dramatic variation from the comparison between the pulses waveform obtained from the instruments and the normal reference envelope diagram should indicate high possibility of earthquake. The proposed detection method of earthquake based on ENPEMF can improve the geodynamic monitoring effect and can enrich earthquake prediction methods. We suggest the prospective further researches are about on the exact sources composition of ENPEMF signals, the distinction between noise and useful signals, and the effect of the Earth's gravity tide and solid tidal wave. This method may also provide a promising application in
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Dim prospects for earthquake prediction
Geller, Robert J.
I was misquoted by C. Lomnitz's [1998] Forum letter (Eos, August 4, 1998, p. 373), which said: [I wonder whether Sasha Gusev [1998] actually believes that branding earthquake prediction a ‘proven nonscience’ [Geller, 1997a] is a paradigm for others to copy.”Readers are invited to verify for themselves that neither “proven nonscience” norv any similar phrase was used by Geller [1997a].
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Earthquake prediction with electromagnetic phenomena
Energy Technology Data Exchange (ETDEWEB)
Hayakawa, Masashi, E-mail: hayakawa@hi-seismo-em.jp [Hayakawa Institute of Seismo Electomagnetics, Co. Ltd., University of Electro-Communications (UEC) Incubation Center, 1-5-1 Chofugaoka, Chofu Tokyo, 182-8585 (Japan); Advanced Wireless & Communications Research Center, UEC, Chofu Tokyo (Japan); Earthquake Analysis Laboratory, Information Systems Inc., 4-8-15, Minami-aoyama, Minato-ku, Tokyo, 107-0062 (Japan); Fuji Security Systems. Co. Ltd., Iwato-cho 1, Shinjyuku-ku, Tokyo (Japan)
2016-02-01
Short-term earthquake (EQ) prediction is defined as prospective prediction with the time scale of about one week, which is considered to be one of the most important and urgent topics for the human beings. If this short-term prediction is realized, casualty will be drastically reduced. Unlike the conventional seismic measurement, we proposed the use of electromagnetic phenomena as precursors to EQs in the prediction, and an extensive amount of progress has been achieved in the field of seismo-electromagnetics during the last two decades. This paper deals with the review on this short-term EQ prediction, including the impossibility myth of EQs prediction by seismometers, the reason why we are interested in electromagnetics, the history of seismo-electromagnetics, the ionospheric perturbation as the most promising candidate of EQ prediction, then the future of EQ predictology from two standpoints of a practical science and a pure science, and finally a brief summary.
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Prediction of the area affected by earthquake-induced landsliding based on seismological parameters
Marc, Odin; Meunier, Patrick; Hovius, Niels
2017-07-01
We present an analytical, seismologically consistent expression for the surface area of the region within which most landslides triggered by an earthquake are located (landslide distribution area). This expression is based on scaling laws relating seismic moment, source depth, and focal mechanism with ground shaking and fault rupture length and assumes a globally constant threshold of acceleration for onset of systematic mass wasting. The seismological assumptions are identical to those recently used to propose a seismologically consistent expression for the total volume and area of landslides triggered by an earthquake. To test the accuracy of the model we gathered geophysical information and estimates of the landslide distribution area for 83 earthquakes. To reduce uncertainties and inconsistencies in the estimation of the landslide distribution area, we propose an objective definition based on the shortest distance from the seismic wave emission line containing 95 % of the total landslide area. Without any empirical calibration the model explains 56 % of the variance in our dataset, and predicts 35 to 49 out of 83 cases within a factor of 2, depending on how we account for uncertainties on the seismic source depth. For most cases with comprehensive landslide inventories we show that our prediction compares well with the smallest region around the fault containing 95 % of the total landslide area. Aspects ignored by the model that could explain the residuals include local variations of the threshold of acceleration and processes modulating the surface ground shaking, such as the distribution of seismic energy release on the fault plane, the dynamic stress drop, and rupture directivity. Nevertheless, its simplicity and first-order accuracy suggest that the model can yield plausible and useful estimates of the landslide distribution area in near-real time, with earthquake parameters issued by standard detection routines.
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Long-term predictability of regions and dates of strong earthquakes
Kubyshen, Alexander; Doda, Leonid; Shopin, Sergey
2016-04-01
Results on the long-term predictability of strong earthquakes are discussed. It is shown that dates of earthquakes with M>5.5 could be determined in advance of several months before the event. The magnitude and the region of approaching earthquake could be specified in the time-frame of a month before the event. Determination of number of M6+ earthquakes, which are expected to occur during the analyzed year, is performed using the special sequence diagram of seismic activity for the century time frame. Date analysis could be performed with advance of 15-20 years. Data is verified by a monthly sequence diagram of seismic activity. The number of strong earthquakes expected to occur in the analyzed month is determined by several methods having a different prediction horizon. Determination of days of potential earthquakes with M5.5+ is performed using astronomical data. Earthquakes occur on days of oppositions of Solar System planets (arranged in a single line). At that, the strongest earthquakes occur under the location of vector "Sun-Solar System barycenter" in the ecliptic plane. Details of this astronomical multivariate indicator still require further research, but it's practical significant is confirmed by practice. Another one empirical indicator of approaching earthquake M6+ is a synchronous variation of meteorological parameters: abrupt decreasing of minimal daily temperature, increasing of relative humidity, abrupt change of atmospheric pressure (RAMES method). Time difference of predicted and actual date is no more than one day. This indicator is registered 104 days before the earthquake, so it was called as Harmonic 104 or H-104. This fact looks paradoxical, but the works of A. Sytinskiy and V. Bokov on the correlation of global atmospheric circulation and seismic events give a physical basis for this empirical fact. Also, 104 days is a quarter of a Chandler period so this fact gives insight on the correlation between the anomalies of Earth orientation
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Implications of fault constitutive properties for earthquake prediction.
Dieterich, J H; Kilgore, B
1996-04-30
The rate- and state-dependent constitutive formulation for fault slip characterizes an exceptional variety of materials over a wide range of sliding conditions. This formulation provides a unified representation of diverse sliding phenomena including slip weakening over a characteristic sliding distance Dc, apparent fracture energy at a rupture front, time-dependent healing after rapid slip, and various other transient and slip rate effects. Laboratory observations and theoretical models both indicate that earthquake nucleation is accompanied by long intervals of accelerating slip. Strains from the nucleation process on buried faults generally could not be detected if laboratory values of Dc apply to faults in nature. However, scaling of Dc is presently an open question and the possibility exists that measurable premonitory creep may precede some earthquakes. Earthquake activity is modeled as a sequence of earthquake nucleation events. In this model, earthquake clustering arises from sensitivity of nucleation times to the stress changes induced by prior earthquakes. The model gives the characteristic Omori aftershock decay law and assigns physical interpretation to aftershock parameters. The seismicity formulation predicts large changes of earthquake probabilities result from stress changes. Two mechanisms for foreshocks are proposed that describe observed frequency of occurrence of foreshock-mainshock pairs by time and magnitude. With the first mechanism, foreshocks represent a manifestation of earthquake clustering in which the stress change at the time of the foreshock increases the probability of earthquakes at all magnitudes including the eventual mainshock. With the second model, accelerating fault slip on the mainshock nucleation zone triggers foreshocks.
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Tsunami Prediction and Earthquake Parameters Estimation in the Red Sea
Sawlan, Zaid A
2012-12-01
Tsunami concerns have increased in the world after the 2004 Indian Ocean tsunami and the 2011 Tohoku tsunami. Consequently, tsunami models have been developed rapidly in the last few years. One of the advanced tsunami models is the GeoClaw tsunami model introduced by LeVeque (2011). This model is adaptive and consistent. Because of different sources of uncertainties in the model, observations are needed to improve model prediction through a data assimilation framework. Model inputs are earthquake parameters and topography. This thesis introduces a real-time tsunami forecasting method that combines tsunami model with observations using a hybrid ensemble Kalman filter and ensemble Kalman smoother. The filter is used for state prediction while the smoother operates smoothing to estimate the earthquake parameters. This method reduces the error produced by uncertain inputs. In addition, state-parameter EnKF is implemented to estimate earthquake parameters. Although number of observations is small, estimated parameters generates a better tsunami prediction than the model. Methods and results of prediction experiments in the Red Sea are presented and the prospect of developing an operational tsunami prediction system in the Red Sea is discussed.
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An application of earthquake prediction algorithm M8 in eastern ...
Indian Academy of Sciences (India)
2Institute of Earthquake Prediction Theory and Mathematical Geophysics, ... located about 70 km from a preceding M7.3 earthquake that occurred in ... local extremes of the seismic density distribution, and in the third approach, CI centers were distributed ...... Bird P 2003 An updated digital model of plate boundaries;.
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Prediction of accident sequence probabilities in a nuclear power plant due to earthquake events
International Nuclear Information System (INIS)
Hudson, J.M.; Collins, J.D.
1980-01-01
This paper presents a methodology to predict accident probabilities in nuclear power plants subject to earthquakes. The resulting computer program accesses response data to compute component failure probabilities using fragility functions. Using logical failure definitions for systems, and the calculated component failure probabilities, initiating event and safety system failure probabilities are synthesized. The incorporation of accident sequence expressions allows the calculation of terminal event probabilities. Accident sequences, with their occurrence probabilities, are finally coupled to a specific release category. A unique aspect of the methodology is an analytical procedure for calculating top event probabilities based on the correlated failure of primary events
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Li, Shuang; Yu, Xiaohui; Zhang, Yanjuan; Zhai, Changhai
2018-01-01
Casualty prediction in a building during earthquakes benefits to implement the economic loss estimation in the performance-based earthquake engineering methodology. Although after-earthquake observations reveal that the evacuation has effects on the quantity of occupant casualties during earthquakes, few current studies consider occupant movements in the building in casualty prediction procedures. To bridge this knowledge gap, a numerical simulation method using refined cellular automata model is presented, which can describe various occupant dynamic behaviors and building dimensions. The simulation on the occupant evacuation is verified by a recorded evacuation process from a school classroom in real-life 2013 Ya'an earthquake in China. The occupant casualties in the building under earthquakes are evaluated by coupling the building collapse process simulation by finite element method, the occupant evacuation simulation, and the casualty occurrence criteria with time and space synchronization. A case study of casualty prediction in a building during an earthquake is provided to demonstrate the effect of occupant movements on casualty prediction.
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Probabilistic approach to earthquake prediction.
Directory of Open Access Journals (Sweden)
G. D'Addezio
2002-06-01
Full Text Available The evaluation of any earthquake forecast hypothesis requires the application of rigorous statistical methods. It implies a univocal definition of the model characterising the concerned anomaly or precursor, so as it can be objectively recognised in any circumstance and by any observer.A valid forecast hypothesis is expected to maximise successes and minimise false alarms. The probability gain associated to a precursor is also a popular way to estimate the quality of the predictions based on such precursor. Some scientists make use of a statistical approach based on the computation of the likelihood of an observed realisation of seismic events, and on the comparison of the likelihood obtained under different hypotheses. This method can be extended to algorithms that allow the computation of the density distribution of the conditional probability of earthquake occurrence in space, time and magnitude. Whatever method is chosen for building up a new hypothesis, the final assessment of its validity should be carried out by a test on a new and independent set of observations. The implementation of this test could, however, be problematic for seismicity characterised by long-term recurrence intervals. Even using the historical record, that may span time windows extremely variable between a few centuries to a few millennia, we have a low probability to catch more than one or two events on the same fault. Extending the record of earthquakes of the past back in time up to several millennia, paleoseismology represents a great opportunity to study how earthquakes recur through time and thus provide innovative contributions to time-dependent seismic hazard assessment. Sets of paleoseimologically dated earthquakes have been established for some faults in the Mediterranean area: the Irpinia fault in Southern Italy, the Fucino fault in Central Italy, the El Asnam fault in Algeria and the Skinos fault in Central Greece. By using the age of the
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International Nuclear Information System (INIS)
Mishima, J.; Schwendiman, L.C.; Ayer, J.E.
1978-10-01
As part of an interdisciplinary study to evaluate the potential radiological consequences of wind hazard and earthquake upon existing commercial mixed oxide fuel fabrication plants, the potential mass airborne releases of plutonium (source terms) from such events are estimated. The estimated souce terms are based upon the fraction of enclosures damaged to three levels of severity (crush, puncture penetrate, and loss of external filter, in order of decreasing severity), called damage ratio, and the airborne release if all enclosures suffered that level of damage. The discussion of damage scenarios and source terms is divided into wind hazard and earthquake scenarios in order of increasing severity. The largest airborne releases from the building were for cases involving the catastrophic collapse of the roof over the major production areas--wind hazard at 110 mph and earthquakes with peak ground accelerations of 0.20 to 0.29 g. Wind hazards at higher air velocities and earthquakes with higher ground acceleration do not result in significantly greater source terms. The source terms were calculated as additional mass of respirable particles released with time up to 4 days; and, under these assumptions, approximately 98% of the mass of material of concern is made airborne from 2 h to 4 days after the event. The overall building source terms from the damage scenarios evaluated are shown in a table. The contribution of individual areas to the overall building source term is presented in order of increasing severity for wind hazard and earthquake
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Is It Possible to Predict Strong Earthquakes?
Polyakov, Y. S.; Ryabinin, G. V.; Solovyeva, A. B.; Timashev, S. F.
2015-07-01
The possibility of earthquake prediction is one of the key open questions in modern geophysics. We propose an approach based on the analysis of common short-term candidate precursors (2 weeks to 3 months prior to strong earthquake) with the subsequent processing of brain activity signals generated in specific types of rats (kept in laboratory settings) who reportedly sense an impending earthquake a few days prior to the event. We illustrate the identification of short-term precursors using the groundwater sodium-ion concentration data in the time frame from 2010 to 2014 (a major earthquake occurred on 28 February 2013) recorded at two different sites in the southeastern part of the Kamchatka Peninsula, Russia. The candidate precursors are observed as synchronized peaks in the nonstationarity factors, introduced within the flicker-noise spectroscopy framework for signal processing, for the high-frequency component of both time series. These peaks correspond to the local reorganizations of the underlying geophysical system that are believed to precede strong earthquakes. The rodent brain activity signals are selected as potential "immediate" (up to 2 weeks) deterministic precursors because of the recent scientific reports confirming that rodents sense imminent earthquakes and the population-genetic model of K irshvink (Soc Am 90, 312-323, 2000) showing how a reliable genetic seismic escape response system may have developed over the period of several hundred million years in certain animals. The use of brain activity signals, such as electroencephalograms, in contrast to conventional abnormal animal behavior observations, enables one to apply the standard "input-sensor-response" approach to determine what input signals trigger specific seismic escape brain activity responses.
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Heraud, J. A.; Centa, V. A.; Bleier, T.
2017-12-01
During the past four years, magnetometers deployed in the Peruvian coast have been providing evidence that the ULF pulses received are indeed generated at the subduction or Benioff zone and are connected with the occurrence of earthquakes within a few kilometers of the source of such pulses. This evidence was presented at the AGU 2015 Fall meeting, showing the results of triangulation of pulses from two magnetometers located in the central area of Peru, using data collected during a two-year period. Additional work has been done and the method has now been expanded to provide the instantaneous energy released at the stress areas on the Benioff zone during the precursory stage, before an earthquake occurs. Collected data from several events and in other parts of the country will be shown in a sequential animated form that illustrates the way energy is released in the ULF part of the electromagnetic spectrum. The process has been extended in time and geographical places. Only pulses associated with the occurrence of earthquakes are taken into account in an area which is highly associated with subduction-zone seismic events and several pulse parameters have been used to estimate a function relating the magnitude of the earthquake with the value of a function generated with those parameters. The results shown, including the animated data video, constitute additional work towards the estimation of the magnitude of an earthquake about to occur, based on electromagnetic pulses that originated at the subduction zone. The method is providing clearer evidence that electromagnetic precursors in effect conveys physical and useful information prior to the advent of a seismic event
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Hirata, N.; Yokoi, S.; Nanjo, K. Z.; Tsuruoka, H.
2012-04-01
One major focus of the current Japanese earthquake prediction research program (2009-2013), which is now integrated with the research program for prediction of volcanic eruptions, is to move toward creating testable earthquake forecast models. For this purpose we started an experiment of forecasting earthquake activity in Japan under the framework of the Collaboratory for the Study of Earthquake Predictability (CSEP) through an international collaboration. We established the CSEP Testing Centre, an infrastructure to encourage researchers to develop testable models for Japan, and to conduct verifiable prospective tests of their model performance. We started the 1st earthquake forecast testing experiment in Japan within the CSEP framework. We use the earthquake catalogue maintained and provided by the Japan Meteorological Agency (JMA). The experiment consists of 12 categories, with 4 testing classes with different time spans (1 day, 3 months, 1 year, and 3 years) and 3 testing regions called "All Japan," "Mainland," and "Kanto." A total of 105 models were submitted, and are currently under the CSEP official suite of tests for evaluating the performance of forecasts. The experiments were completed for 92 rounds for 1-day, 6 rounds for 3-month, and 3 rounds for 1-year classes. For 1-day testing class all models passed all the CSEP's evaluation tests at more than 90% rounds. The results of the 3-month testing class also gave us new knowledge concerning statistical forecasting models. All models showed a good performance for magnitude forecasting. On the other hand, observation is hardly consistent in space distribution with most models when many earthquakes occurred at a spot. Now we prepare the 3-D forecasting experiment with a depth range of 0 to 100 km in Kanto region. The testing center is improving an evaluation system for 1-day class experiment to finish forecasting and testing results within one day. The special issue of 1st part titled Earthquake Forecast
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Last, Mark; Rabinowitz, Nitzan; Leonard, Gideon
2016-01-01
This paper explores several data mining and time series analysis methods for predicting the magnitude of the largest seismic event in the next year based on the previously recorded seismic events in the same region. The methods are evaluated on a catalog of 9,042 earthquake events, which took place between 01/01/1983 and 31/12/2010 in the area of Israel and its neighboring countries. The data was obtained from the Geophysical Institute of Israel. Each earthquake record in the catalog is associated with one of 33 seismic regions. The data was cleaned by removing foreshocks and aftershocks. In our study, we have focused on ten most active regions, which account for more than 80% of the total number of earthquakes in the area. The goal is to predict whether the maximum earthquake magnitude in the following year will exceed the median of maximum yearly magnitudes in the same region. Since the analyzed catalog includes only 28 years of complete data, the last five annual records of each region (referring to the years 2006-2010) are kept for testing while using the previous annual records for training. The predictive features are based on the Gutenberg-Richter Ratio as well as on some new seismic indicators based on the moving averages of the number of earthquakes in each area. The new predictive features prove to be much more useful than the indicators traditionally used in the earthquake prediction literature. The most accurate result (AUC = 0.698) is reached by the Multi-Objective Info-Fuzzy Network (M-IFN) algorithm, which takes into account the association between two target variables: the number of earthquakes and the maximum earthquake magnitude during the same year.
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A mathematical model for predicting earthquake occurrence ...
African Journals Online (AJOL)
We consider the continental crust under damage. We use the observed results of microseism in many seismic stations of the world which was established to study the time series of the activities of the continental crust with a view to predicting possible time of occurrence of earthquake. We consider microseism time series ...
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A 30-year history of earthquake crisis communication in California and lessons for the future
Jones, L.
2015-12-01
The first statement from the US Geological Survey to the California Office of Emergency Services quantifying the probability of a possible future earthquake was made in October 1985 about the probability (approximately 5%) that a M4.7 earthquake located directly beneath the Coronado Bay Bridge in San Diego would be a foreshock to a larger earthquake. In the next 30 years, publication of aftershock advisories have become routine and formal statements about the probability of a larger event have been developed in collaboration with the California Earthquake Prediction Evaluation Council (CEPEC) and sent to CalOES more than a dozen times. Most of these were subsequently released to the public. These communications have spanned a variety of approaches, with and without quantification of the probabilities, and using different ways to express the spatial extent and the magnitude distribution of possible future events. The USGS is re-examining its approach to aftershock probability statements and to operational earthquake forecasting with the goal of creating pre-vetted automated statements that can be released quickly after significant earthquakes. All of the previous formal advisories were written during the earthquake crisis. The time to create and release a statement became shorter with experience from the first public advisory (to the 1988 Lake Elsman earthquake) that was released 18 hours after the triggering event, but was never completed in less than 2 hours. As was done for the Parkfield experiment, the process will be reviewed by CEPEC and NEPEC (National Earthquake Prediction Evaluation Council) so the statements can be sent to the public automatically. This talk will review the advisories, the variations in wording and the public response and compare this with social science research about successful crisis communication, to create recommendations for future advisories
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EPOS1 - a multiparameter measuring system to earthquake prediction research
Energy Technology Data Exchange (ETDEWEB)
Streil, T.; Oeser, V. [SARAD GmbH, Dresden (Germany); Heinicke, J.; Koch, U.; Wiegand, J.
1998-12-31
The approach to earthquake prediction by geophysical, geochemical and hydrological measurements is a long and winding road. Nevertheless, the results show a progress in that field (e.g. Kobe). This progress is also a result of a new generation of measuring equipment. SARAD has developed a versatile measuring system (EPOS1) based on experiences and recent results from different research groups. It is able to record selected parameters suitable to earthquake prediction research. A micro-computer system handles data exchange, data management and control. It is connected to a modular sensor system. Sensor modules can be selected according to the actual needs at the measuring site. (author)
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Stabilizing intermediate-term medium-range earthquake predictions
International Nuclear Information System (INIS)
Kossobokov, V.G.; Romashkova, L.L.; Panza, G.F.; Peresan, A.
2001-12-01
A new scheme for the application of the intermediate-term medium-range earthquake prediction algorithm M8 is proposed. The scheme accounts for the natural distribution of seismic activity, eliminates the subjectivity in the positioning of the areas of investigation and provides additional stability of the predictions with respect to the original variant. According to the retroactive testing in Italy and adjacent regions, this improvement is achieved without any significant change of the alarm volume in comparison with the results published so far. (author)
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Real-time numerical shake prediction and updating for earthquake early warning
Wang, Tianyun; Jin, Xing; Wei, Yongxiang; Huang, Yandan
2017-12-01
Ground motion prediction is important for earthquake early warning systems, because the region's peak ground motion indicates the potential disaster. In order to predict the peak ground motion quickly and precisely with limited station wave records, we propose a real-time numerical shake prediction and updating method. Our method first predicts the ground motion based on the ground motion prediction equation after P waves detection of several stations, denoted as the initial prediction. In order to correct the prediction error of the initial prediction, an updating scheme based on real-time simulation of wave propagation is designed. Data assimilation technique is incorporated to predict the distribution of seismic wave energy precisely. Radiative transfer theory and Monte Carlo simulation are used for modeling wave propagation in 2-D space, and the peak ground motion is calculated as quickly as possible. Our method has potential to predict shakemap, making the potential disaster be predicted before the real disaster happens. 2008 M S8.0 Wenchuan earthquake is studied as an example to show the validity of the proposed method.
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Statistical short-term earthquake prediction.
Kagan, Y Y; Knopoff, L
1987-06-19
A statistical procedure, derived from a theoretical model of fracture growth, is used to identify a foreshock sequence while it is in progress. As a predictor, the procedure reduces the average uncertainty in the rate of occurrence for a future strong earthquake by a factor of more than 1000 when compared with the Poisson rate of occurrence. About one-third of all main shocks with local magnitude greater than or equal to 4.0 in central California can be predicted in this way, starting from a 7-year database that has a lower magnitude cut off of 1.5. The time scale of such predictions is of the order of a few hours to a few days for foreshocks in the magnitude range from 2.0 to 5.0.
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International Nuclear Information System (INIS)
Enescu, D.; Chitaru, C.; Enescu, B.D.
1999-01-01
The relevance of bio-seismic research for the short-term prediction of strong Vrancea earthquakes is underscored. An unusual animal behavior before and during Vrancea earthquakes is described and illustrated in the individual case of the major earthquake of March 4, 1977. Several hypotheses to account for the uncommon behavior of bio-systems in relation to earthquakes in general and strong Vrancea earthquakes in particular are discussed in the second section. It is reminded that promising preliminary results concerning the identification of seismic-electromagnetic precursor signals have been obtained in the Vrancea seismogenic area using special, highly sensitive equipment. The need to correlate bio-seismic and seismic-electromagnetic researches is evident. Further investigations are suggested and urgent steps are proposed in order to achieve a successful short-term prediction of strong Vrancea earthquakes. (authors)
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The use of radon gas techniques for earthquake prediction
International Nuclear Information System (INIS)
Al-Hilal, M.
1993-01-01
This scientific article explains the applications of radon gas measurements in water and soil for monitoring fault activities and earthquake prediction. It also emphasizes, through some worldwide examples presented from Tashkent Basin in U.S.S.R. and from San Andreas fault in U.S.A, that the use of radon gas technique in fault originated water as well as in soil gases can be considered as an important geological-tool, within the general framework of earthquake prediction because of the coherent and time anomalous relationship between the density of alpha particles due to radon decay and between the tectonic activity level along fault zones. The article also indicates, and through the practical experience of the author, to the possibility of applying such techniques in certain parts of Syria. (author). 6 refs., 4 figs
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International Nuclear Information System (INIS)
Men, Ke-Pei; Zhao, Kai
2014-01-01
M ≥ 7 earthquakes have showed an obvious commensurability and orderliness in Xinjiang of China and its adjacent region since 1800. The main orderly values are 30 a x k (k = 1, 2, 3), 11 ∝ 12 a, 41 ∝ 43 a, 18 ∝ 19 a, and 5 ∝ 6 a. In the guidance of the information forecasting theory of Wen-Bo Weng, based on previous research results, combining ordered network structure analysis with complex network technology, we focus on the prediction summary of M ≥ 7 earthquakes by using the ordered network structure, and add new information to further optimize network, hence construct the 2D- and 3D-ordered network structure of M ≥ 7 earthquakes. In this paper, the network structure revealed fully the regularity of seismic activity of M ≥ 7 earthquakes in the study region during the past 210 years. Based on this, the Karakorum M7.1 earthquake in 1996, the M7.9 earthquake on the frontier of Russia, Mongol, and China in 2003, and two Yutian M7.3 earthquakes in 2008 and 2014 were predicted successfully. At the same time, a new prediction opinion is presented that the future two M ≥ 7 earthquakes will probably occur around 2019-2020 and 2025-2026 in this region. The results show that large earthquake occurred in defined region can be predicted. The method of ordered network structure analysis produces satisfactory results for the mid-and-long term prediction of M ≥ 7 earthquakes.
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Short-Term Forecasting of Taiwanese Earthquakes Using a Universal Model of Fusion-Fission Processes
Cheong, Siew Ann; Tan, Teck Liang; Chen, Chien-Chih; Chang, Wu-Lung; Liu, Zheng; Chew, Lock Yue; Sloot, Peter M. A.; Johnson, Neil F.
2014-01-01
Predicting how large an earthquake can be, where and when it will strike remains an elusive goal in spite of the ever-increasing volume of data collected by earth scientists. In this paper, we introduce a universal model of fusion-fission processes that can be used to predict earthquakes starting from catalog data. We show how the equilibrium dynamics of this model very naturally explains the Gutenberg-Richter law. Using the high-resolution earthquake catalog of Taiwan between Jan 1994 and Feb 2009, we illustrate how out-of-equilibrium spatio-temporal signatures in the time interval between earthquakes and the integrated energy released by earthquakes can be used to reliably determine the times, magnitudes, and locations of large earthquakes, as well as the maximum numbers of large aftershocks that would follow. PMID:24406467
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Intermediate-term earthquake prediction and seismic zoning in Northern Italy
International Nuclear Information System (INIS)
Panza, G.F.; Orozova Stanishkova, I.; Costa, G.; Vaccari, F.
1993-12-01
The algorithm CN for intermediate earthquake prediction has been applied to an area in Northern Italy, which has been chosen according to a recently proposed seismotectonic model. Earthquakes with magnitude ≥ 5.4 occur in the area with a relevant frequency and their occurrence is predicted by algorithm CN. Therefore a seismic hazard analysis has been performed using a deterministic procedure, based on the computation of complete synthetic seismograms. The results are summarized in a map giving the distribution of peak ground acceleration, but the complete time series are available, which can be used by civil engineers in the design of new seismo-resistant constructions and in the retrofitting of the existing ones. This risk reduction action should be intensified in connection with warnings issued on the basis of the forward predictions made by CN. (author). Refs, 7 figs, 1 tab
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A Hybrid Ground-Motion Prediction Equation for Earthquakes in Western Alberta
Spriggs, N.; Yenier, E.; Law, A.; Moores, A. O.
2015-12-01
Estimation of ground-motion amplitudes that may be produced by future earthquakes constitutes the foundation of seismic hazard assessment and earthquake-resistant structural design. This is typically done by using a prediction equation that quantifies amplitudes as a function of key seismological variables such as magnitude, distance and site condition. In this study, we develop a hybrid empirical prediction equation for earthquakes in western Alberta, where evaluation of seismic hazard associated with induced seismicity is of particular interest. We use peak ground motions and response spectra from recorded seismic events to model the regional source and attenuation attributes. The available empirical data is limited in the magnitude range of engineering interest (M>4). Therefore, we combine empirical data with a simulation-based model in order to obtain seismologically informed predictions for moderate-to-large magnitude events. The methodology is two-fold. First, we investigate the shape of geometrical spreading in Alberta. We supplement the seismic data with ground motions obtained from mining/quarry blasts, in order to gain insights into the regional attenuation over a wide distance range. A comparison of ground-motion amplitudes for earthquakes and mining/quarry blasts show that both event types decay at similar rates with distance and demonstrate a significant Moho-bounce effect. In the second stage, we calibrate the source and attenuation parameters of a simulation-based prediction equation to match the available amplitude data from seismic events. We model the geometrical spreading using a trilinear function with attenuation rates obtained from the first stage, and calculate coefficients of anelastic attenuation and site amplification via regression analysis. This provides a hybrid ground-motion prediction equation that is calibrated for observed motions in western Alberta and is applicable to moderate-to-large magnitude events.
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Earthquake Prediction Research In Iceland, Applications For Hazard Assessments and Warnings
Stefansson, R.
Earthquake prediction research in Iceland, applications for hazard assessments and warnings. The first multinational earthquake prediction research project in Iceland was the Eu- ropean Council encouraged SIL project of the Nordic countries, 1988-1995. The path selected for this research was to study the physics of crustal processes leading to earth- quakes. It was considered that small earthquakes, down to magnitude zero, were the most significant for this purpose, because of the detailed information which they pro- vide both in time and space. The test area for the project was the earthquake prone region of the South Iceland seismic zone (SISZ). The PRENLAB and PRENLAB-2 projects, 1996-2000 supported by the European Union were a direct continuation of the SIL project, but with a more multidisciplinary approach. PRENLAB stands for "Earthquake prediction research in a natural labo- ratory". The basic objective was to advance our understanding in general on where, when and how dangerous NH10earthquake motion might strike. Methods were devel- oped to study crustal processes and conditions, by microearthquake information, by continuous GPS, InSAR, theoretical modelling, fault mapping and paleoseismology. New algorithms were developed for short term warnings. A very useful short term warning was issued twice in the year 2000, one for a sudden start of an eruption in Volcano Hekla February 26, and the other 25 hours before a second (in a sequence of two) magnitude 6.6 (Ms) earthquake in the South Iceland seismic zone in June 21, with the correct location and approximate size. A formal short term warning, although not going to the public, was also issued before a magnitude 5 earthquake in November 1998. In the presentation it will be shortly described what these warnings were based on. A general hazard assessmnets was presented in scientific journals 10-15 years ago assessing within a few kilometers the location of the faults of the two 2000 earthquakes and suggesting
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Radon/helium studies for earthquake prediction N-W Himalaya
International Nuclear Information System (INIS)
Virk, H.S.
1999-01-01
The paper presents the preliminary data of radon monitoring stated in the Himalayan orogenic belt. Radon anomalies are correlated with microseismic activity in the N-W Himalaya. The He/Rn ratio will be used as a predictive tool for earthquakes
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Recent Achievements of the Collaboratory for the Study of Earthquake Predictability
Jackson, D. D.; Liukis, M.; Werner, M. J.; Schorlemmer, D.; Yu, J.; Maechling, P. J.; Zechar, J. D.; Jordan, T. H.
2015-12-01
Maria Liukis, SCEC, USC; Maximilian Werner, University of Bristol; Danijel Schorlemmer, GFZ Potsdam; John Yu, SCEC, USC; Philip Maechling, SCEC, USC; Jeremy Zechar, Swiss Seismological Service, ETH; Thomas H. Jordan, SCEC, USC, and the CSEP Working Group The Collaboratory for the Study of Earthquake Predictability (CSEP) supports a global program to conduct prospective earthquake forecasting experiments. CSEP testing centers are now operational in California, New Zealand, Japan, China, and Europe with 435 models under evaluation. The California testing center, operated by SCEC, has been operational since Sept 1, 2007, and currently hosts 30-minute, 1-day, 3-month, 1-year and 5-year forecasts, both alarm-based and probabilistic, for California, the Western Pacific, and worldwide. We have reduced testing latency, implemented prototype evaluation of M8 forecasts, and are currently developing formats and procedures to evaluate externally-hosted forecasts and predictions. These efforts are related to CSEP support of the USGS program in operational earthquake forecasting and a DHS project to register and test external forecast procedures from experts outside seismology. A retrospective experiment for the 2010-2012 Canterbury earthquake sequence has been completed, and the results indicate that some physics-based and hybrid models outperform purely statistical (e.g., ETAS) models. The experiment also demonstrates the power of the CSEP cyberinfrastructure for retrospective testing. Our current development includes evaluation strategies that increase computational efficiency for high-resolution global experiments, such as the evaluation of the Global Earthquake Activity Rate (GEAR) model. We describe the open-source CSEP software that is available to researchers as they develop their forecast models (http://northridge.usc.edu/trac/csep/wiki/MiniCSEP). We also discuss applications of CSEP infrastructure to geodetic transient detection and how CSEP procedures are being
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Serata, S.
2006-12-01
The Serata Stressmeter has been developed to measure and monitor earthquake shear stress build-up along shallow active faults. The development work made in the past 25 years has established the Stressmeter as an automatic stress measurement system to study timing of forthcoming major earthquakes in support of the current earthquake prediction studies based on statistical analysis of seismological observations. In early 1982, a series of major Man-made earthquakes (magnitude 4.5-5.0) suddenly occurred in an area over deep underground potash mine in Saskatchewan, Canada. By measuring underground stress condition of the mine, the direct cause of the earthquake was disclosed. The cause was successfully eliminated by controlling the stress condition of the mine. The Japanese government was interested in this development and the Stressmeter was introduced to the Japanese government research program for earthquake stress studies. In Japan the Stressmeter was first utilized for direct measurement of the intrinsic lateral tectonic stress gradient G. The measurement, conducted at the Mt. Fuji Underground Research Center of the Japanese government, disclosed the constant natural gradients of maximum and minimum lateral stresses in an excellent agreement with the theoretical value, i.e., G = 0.25. All the conventional methods of overcoring, hydrofracturing and deformation, which were introduced to compete with the Serata method, failed demonstrating the fundamental difficulties of the conventional methods. The intrinsic lateral stress gradient determined by the Stressmeter for the Japanese government was found to be the same with all the other measurements made by the Stressmeter in Japan. The stress measurement results obtained by the major international stress measurement work in the Hot Dry Rock Projects conducted in USA, England and Germany are found to be in good agreement with the Stressmeter results obtained in Japan. Based on this broad agreement, a solid geomechanical
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Dussaillant, Francisca; Apablaza, Mauricio
2017-08-01
After a major earthquake, the assignment of scarce mental health emergency personnel to different geographic areas is crucial to the effective management of the crisis. The scarce information that is available in the aftermath of a disaster may be valuable in helping predict where are the populations that are in most need. The objectives of this study were to derive algorithms to predict posttraumatic stress (PTS) symptom prevalence and local distribution after an earthquake and to test whether there are algorithms that require few input data and are still reasonably predictive. A rich database of PTS symptoms, informed after Chile's 2010 earthquake and tsunami, was used. Several model specifications for the mean and centiles of the distribution of PTS symptoms, together with posttraumatic stress disorder (PTSD) prevalence, were estimated via linear and quantile regressions. The models varied in the set of covariates included. Adjusted R2 for the most liberal specifications (in terms of numbers of covariates included) ranged from 0.62 to 0.74, depending on the outcome. When only including peak ground acceleration (PGA), poverty rate, and household damage in linear and quadratic form, predictive capacity was still good (adjusted R2 from 0.59 to 0.67 were obtained). Information about local poverty, household damage, and PGA can be used as an aid to predict PTS symptom prevalence and local distribution after an earthquake. This can be of help to improve the assignment of mental health personnel to the affected localities. Dussaillant F , Apablaza M . Predicting posttraumatic stress symptom prevalence and local distribution after an earthquake with scarce data. Prehosp Disaster Med. 2017;32(4):357-367.
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Prediction of the occurrence of related strong earthquakes in Italy
International Nuclear Information System (INIS)
Vorobieva, I.A.; Panza, G.F.
1993-06-01
In the seismic flow it is often observed that a Strong Earthquake (SE), is followed by Related Strong Earthquakes (RSEs), which occur near the epicentre of the SE with origin time rather close to the origin time of the SE. The algorithm for the prediction of the occurrence of a RSE has been developed and applied for the first time to the seismicity data of the California-Nevada region and has been successfully tested in several regions of the World, the statistical significance of the result being 97%. So far, it has been possible to make five successful forward predictions, with no false alarms or failures to predict. The algorithm is applied here to the Italian territory, where the occurrence of RSEs is a particularly rare phenomenon. Our results show that the standard algorithm is successfully directly applicable without any adjustment of the parameters. Eleven SEs are considered. Of them, three are followed by a RSE, as predicted by the algorithm, eight SEs are not followed by a RSE, and the algorithm predicts this behaviour for seven of them, giving rise to only one false alarm. Since, in Italy, quite often the series of strong earthquakes are relatively short, the algorithm has been extended to handle such situation. The result of this experiment indicates that it is possible to attempt to test a SE, for the occurrence of a RSE, soon after the occurrence of the SE itself, performing timely ''preliminary'' recognition on reduced data sets. This fact, the high confidence level of the retrospective analysis, and the first successful forward predictions, made in different parts of the World, indicates that, even if additional tests are desirable, the algorithm can already be considered for routine application to Civil Defence. (author). Refs, 3 figs, 7 tabs
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Radon monitoring and its application for earthquake prediction
International Nuclear Information System (INIS)
Ramchandran, T.V.; Shaikh, A.N.; Khan, A.H.; Mayya, Y.S.; Puranik, V.D.; Venkat Raj, V.
2004-12-01
Concentrations ofa wide range of terrestrial gases containing radionuclides like 222 Rn (Radon), H 2 (Hydrogen), Hg (Mercury), CO 2 (Carbon dioxide) and He 4 (Helium) in ground water and soil air have commonly been found to be anomalously high along active faults, suggesting that these faults may be the path for least resistance for the out gassing processes of the solid earth. Among the naturally occurring radionucludes, the 238 U decay series has received great attention in connection with the earthquake prediction and monitoring research all over the world. Due to its nearly ubiquitous occurrence, appreciable abundance, chemical inactivity and convenient half-life (3.823 d), 222 Rn in the 238 U series is the most extensively studied one in this regard. In this report, a brief account of the application of 222 Rn monitoring carried out all over the world, studies carried out in India, modeling of earthquake predictions, measurement techniques, measuring equipments, its availability in India, Indian radon monitoring programme and its prospects are presented. (author)
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Automated radon-thoron monitoring for earthquake prediction research
International Nuclear Information System (INIS)
Shapiro, M.H.; Melvin, J.D.; Copping, N.A.; Tombrello, T.A.; Whitcomb, J.H.
1980-01-01
This paper describes an automated instrument for earthquake prediction research which monitors the emission of radon ( 222 Rn) and thoron ( 220 Rn) from rock. The instrument uses aerosol filtration techniques and beta counting to determine radon and thoron levels. Data from the first year of operation of a field prototype suggest an annual cycle in the radon level at the site which is related to thermoelastic strains in the crust. Two anomalous increases in the radon level of short duration have been observed during the first year of operation. One anomaly appears to have been a precursor for a nearby earthquake (2.8 magnitude, Richter scale), and the other may have been associated with changing hydrological conditions resulting from heavy rainfall
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Foreshock sequences and short-term earthquake predictability on East Pacific Rise transform faults.
McGuire, Jeffrey J; Boettcher, Margaret S; Jordan, Thomas H
2005-03-24
East Pacific Rise transform faults are characterized by high slip rates (more than ten centimetres a year), predominantly aseismic slip and maximum earthquake magnitudes of about 6.5. Using recordings from a hydroacoustic array deployed by the National Oceanic and Atmospheric Administration, we show here that East Pacific Rise transform faults also have a low number of aftershocks and high foreshock rates compared to continental strike-slip faults. The high ratio of foreshocks to aftershocks implies that such transform-fault seismicity cannot be explained by seismic triggering models in which there is no fundamental distinction between foreshocks, mainshocks and aftershocks. The foreshock sequences on East Pacific Rise transform faults can be used to predict (retrospectively) earthquakes of magnitude 5.4 or greater, in narrow spatial and temporal windows and with a high probability gain. The predictability of such transform earthquakes is consistent with a model in which slow slip transients trigger earthquakes, enrich their low-frequency radiation and accommodate much of the aseismic plate motion.
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Jianjun, X.; Bingjie, Y.; Rongji, W.
2018-03-01
The purpose of this paper was to improve catastrophe insurance level. Firstly, earthquake predictions were carried out using mathematical analysis method. Secondly, the foreign catastrophe insurances’ policies and models were compared. Thirdly, the suggestions on catastrophe insurances to China were discussed. The further study should be paid more attention on the earthquake prediction by introducing big data.
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Heki, K.; He, L.
2017-12-01
We showed that positive and negative electron density anomalies emerge above the fault immediately before they rupture, 40/20/10 minutes before Mw9/8/7 earthquakes (Heki, 2011 GRL; Heki and Enomoto, 2013 JGR; He and Heki 2017 JGR). These signals are stronger for earthquake with larger Mw and under higher background vertical TEC (total electron conetent) (Heki and Enomoto, 2015 JGR). The epicenter, the positive and the negative anomalies align along the local geomagnetic field (He and Heki, 2016 GRL), suggesting electric fields within ionosphere are responsible for making the anomalies (Kuo et al., 2014 JGR; Kelley et al., 2017 JGR). Here we suppose the next Nankai Trough earthquake that may occur within a few tens of years in Southwest Japan, and will discuss if we can recognize its preseismic signatures in TEC by real-time observations with GNSS.During high geomagnetic activities, large-scale traveling ionospheric disturbances (LSTID) often propagate from auroral ovals toward mid-latitude regions, and leave similar signatures to preseismic anomalies. This is a main obstacle to use preseismic TEC changes for practical short-term earthquake prediction. In this presentation, we show that the same anomalies appeared 40 minutes before the mainshock above northern Australia, the geomagnetically conjugate point of the 2011 Tohoku-oki earthquake epicenter. This not only demonstrates that electric fields play a role in making the preseismic TEC anomalies, but also offers a possibility to discriminate preseismic anomalies from those caused by LSTID. By monitoring TEC in the conjugate areas in the two hemisphere, we can recognize anomalies with simultaneous onset as those caused by within-ionosphere electric fields (e.g. preseismic anomalies, night-time MSTID) and anomalies without simultaneous onset as gravity-wave origin disturbances (e.g. LSTID, daytime MSTID).
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CN earthquake prediction algorithm and the monitoring of the future strong Vrancea events
International Nuclear Information System (INIS)
Moldoveanu, C.L.; Radulian, M.; Novikova, O.V.; Panza, G.F.
2002-01-01
The strong earthquakes originating at intermediate-depth in the Vrancea region (located in the SE corner of the highly bent Carpathian arc) represent one of the most important natural disasters able to induce heavy effects (high tool of casualties and extensive damage) in the Romanian territory. The occurrence of these earthquakes is irregular, but not infrequent. Their effects are felt over a large territory, from Central Europe to Moscow and from Greece to Scandinavia. The largest cultural and economical center exposed to the seismic risk due to the Vrancea earthquakes is Bucharest. This metropolitan area (230 km 2 wide) is characterized by the presence of 2.5 million inhabitants (10% of the country population) and by a considerable number of high-risk structures and infrastructures. The best way to face strong earthquakes is to mitigate the seismic risk by using the two possible complementary approaches represented by (a) the antiseismic design of structures and infrastructures (able to support strong earthquakes without significant damage), and (b) the strong earthquake prediction (in terms of alarm intervals declared for long, intermediate or short-term space-and time-windows). The intermediate term medium-range earthquake prediction represents the most realistic target to be reached at the present state of knowledge. The alarm declared in this case extends over a time window of about one year or more, and a space window of a few hundreds of kilometers. In the case of Vrancea events the spatial uncertainty is much less, being of about 100 km. The main measures for the mitigation of the seismic risk allowed by the intermediate-term medium-range prediction are: (a) verification of the buildings and infrastructures stability and reinforcement measures when required, (b) elaboration of emergency plans of action, (c) schedule of the main actions required in order to restore the normality of the social and economical life after the earthquake. The paper presents the
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Can radon gas measurements be used to predict earthquakes?
International Nuclear Information System (INIS)
2009-01-01
After the tragic earthquake of April 6, 2009 in Aquila (Abruzzo), a debate has begun in Italy regarding the alleged prediction of this earthquake by a scientist working in the Gran Sasso National Laboratory, based on radon content measurements. Radon is a radioactive gas originating from the decay of natural radioactive elements present in the soil. IRSN specialists are actively involved in ongoing research projects on the impact of mechanical stresses on radon emissions from underground structures, and some of their results dating from several years ago are being brought up in this debate. These specialists are therefore currently presenting their perspective on the relationships between radon emissions and seismic activity, based on publications on the subject. (authors)
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Energy Technology Data Exchange (ETDEWEB)
Ts' ai, T H
1977-11-01
Chinese folk wisdom has long seen a relationship between ground water and earthquakes. Before an earthquake there is often an unusual change in the ground water level and volume of flow. Changes in the amount of particulate matter in ground water as well as changes in color, bubbling, gas emission, and noises and geysers are also often observed before earthquakes. Analysis of these features can help predict earthquakes. Other factors unrelated to earthquakes can cause some of these changes, too. As a first step it is necessary to find sites which are sensitive to changes in ground stress to be used as sensor points for predicting earthquakes. The necessary features are described. Recording of seismic waves of earthquake aftershocks is also an important part of earthquake predictions.
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An interdisciplinary approach to study Pre-Earthquake processes
Ouzounov, D.; Pulinets, S. A.; Hattori, K.; Taylor, P. T.
2017-12-01
We will summarize a multi-year research effort on wide-ranging observations of pre-earthquake processes. Based on space and ground data we present some new results relevant to the existence of pre-earthquake signals. Over the past 15-20 years there has been a major revival of interest in pre-earthquake studies in Japan, Russia, China, EU, Taiwan and elsewhere. Recent large magnitude earthquakes in Asia and Europe have shown the importance of these various studies in the search for earthquake precursors either for forecasting or predictions. Some new results were obtained from modeling of the atmosphere-ionosphere connection and analyses of seismic records (foreshocks /aftershocks), geochemical, electromagnetic, and thermodynamic processes related to stress changes in the lithosphere, along with their statistical and physical validation. This cross - disciplinary approach could make an impact on our further understanding of the physics of earthquakes and the phenomena that precedes their energy release. We also present the potential impact of these interdisciplinary studies to earthquake predictability. A detail summary of our approach and that of several international researchers will be part of this session and will be subsequently published in a new AGU/Wiley volume. This book is part of the Geophysical Monograph series and is intended to show the variety of parameters seismic, atmospheric, geochemical and historical involved is this important field of research and will bring this knowledge and awareness to a broader geosciences community.
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Earthquake forecasting and warning
Energy Technology Data Exchange (ETDEWEB)
Rikitake, T.
1983-01-01
This review briefly describes two other books on the same subject either written or partially written by Rikitake. In this book, the status of earthquake prediction efforts in Japan, China, the Soviet Union, and the United States are updated. An overview of some of the organizational, legal, and societal aspects of earthquake prediction in these countries is presented, and scientific findings of precursory phenomena are included. A summary of circumstances surrounding the 1975 Haicheng earthquake, the 1978 Tangshan earthquake, and the 1976 Songpan-Pingwu earthquake (all magnitudes = 7.0) in China and the 1978 Izu-Oshima earthquake in Japan is presented. This book fails to comprehensively summarize recent advances in earthquake prediction research.
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Analysing earthquake slip models with the spatial prediction comparison test
Zhang, L.; Mai, Paul Martin; Thingbaijam, Kiran Kumar; Razafindrakoto, H. N. T.; Genton, Marc G.
2014-01-01
Earthquake rupture models inferred from inversions of geophysical and/or geodetic data exhibit remarkable variability due to uncertainties in modelling assumptions, the use of different inversion algorithms, or variations in data selection and data processing. A robust statistical comparison of different rupture models obtained for a single earthquake is needed to quantify the intra-event variability, both for benchmark exercises and for real earthquakes. The same approach may be useful to characterize (dis-)similarities in events that are typically grouped into a common class of events (e.g. moderate-size crustal strike-slip earthquakes or tsunamigenic large subduction earthquakes). For this purpose, we examine the performance of the spatial prediction comparison test (SPCT), a statistical test developed to compare spatial (random) fields by means of a chosen loss function that describes an error relation between a 2-D field (‘model’) and a reference model. We implement and calibrate the SPCT approach for a suite of synthetic 2-D slip distributions, generated as spatial random fields with various characteristics, and then apply the method to results of a benchmark inversion exercise with known solution. We find the SPCT to be sensitive to different spatial correlations lengths, and different heterogeneity levels of the slip distributions. The SPCT approach proves to be a simple and effective tool for ranking the slip models with respect to a reference model.
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Analysing earthquake slip models with the spatial prediction comparison test
Zhang, L.
2014-11-10
Earthquake rupture models inferred from inversions of geophysical and/or geodetic data exhibit remarkable variability due to uncertainties in modelling assumptions, the use of different inversion algorithms, or variations in data selection and data processing. A robust statistical comparison of different rupture models obtained for a single earthquake is needed to quantify the intra-event variability, both for benchmark exercises and for real earthquakes. The same approach may be useful to characterize (dis-)similarities in events that are typically grouped into a common class of events (e.g. moderate-size crustal strike-slip earthquakes or tsunamigenic large subduction earthquakes). For this purpose, we examine the performance of the spatial prediction comparison test (SPCT), a statistical test developed to compare spatial (random) fields by means of a chosen loss function that describes an error relation between a 2-D field (‘model’) and a reference model. We implement and calibrate the SPCT approach for a suite of synthetic 2-D slip distributions, generated as spatial random fields with various characteristics, and then apply the method to results of a benchmark inversion exercise with known solution. We find the SPCT to be sensitive to different spatial correlations lengths, and different heterogeneity levels of the slip distributions. The SPCT approach proves to be a simple and effective tool for ranking the slip models with respect to a reference model.
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Earthquake prediction using extinct monogenetic volcanoes: A possible new research strategy
Szakács, Alexandru
2011-04-01
Volcanoes are extremely effective transmitters of matter, energy and information from the deep Earth towards its surface. Their capacities as information carriers are far to be fully exploited so far. Volcanic conduits can be viewed in general as rod-like or sheet-like vertical features with relatively homogenous composition and structure crosscutting geological structures of far more complexity and compositional heterogeneity. Information-carrying signals such as earthquake precursor signals originating deep below the Earth surface are transmitted with much less loss of information through homogenous vertically extended structures than through the horizontally segmented heterogeneous lithosphere or crust. Volcanic conduits can thus be viewed as upside-down "antennas" or waveguides which can be used as privileged pathways of any possible earthquake precursor signal. In particular, conduits of monogenetic volcanoes are promising transmitters of deep Earth information to be received and decoded at surface monitoring stations because the expected more homogenous nature of their rock-fill as compared to polygenetic volcanoes. Among monogenetic volcanoes those with dominantly effusive activity appear as the best candidates for privileged earthquake monitoring sites. In more details, effusive monogenetic volcanic conduits filled with rocks of primitive parental magma composition indicating direct ascent from sub-lithospheric magma-generating areas are the most suitable. Further selection criteria may include age of the volcanism considered and the presence of mantle xenoliths in surface volcanic products indicating direct and straightforward link between the deep lithospheric mantle and surface through the conduit. Innovative earthquake prediction research strategies can be based and developed on these grounds by considering conduits of selected extinct monogenetic volcanoes and deep trans-crustal fractures as privileged emplacement sites of seismic monitoring stations
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An Ilustrative Nuclide Release Behavior from an HLW Repository due to an Earthquake Event
International Nuclear Information System (INIS)
Lee, Youn-Myoung; Hwang, Yong-Soo; Choi, Jong-Won
2008-01-01
Program for the evaluation of a high-level waste repository which is conceptually modeled. During the last few years, programs developed with the aid of AMBER and GoldSim by which nuclide transports in the near- and far-field of a repository as well as transport through the biosphere under various normal and disruptive release scenarios could be modeled and evaluated, have been continuously demonstrated. To show its usability, as similarly done for the natural groundwater flow scheme, influence of a possible disruptive event on a nuclide release behavior from an HLW repository system caused naturally due to an earthquake has been investigated and illustrated with the newly developed GoldSim program
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Thomas, J.N.; Masci, F; Love, Jeffrey J.
2015-01-01
Several recently published reports have suggested that semi-stationary linear-cloud formations might be causally precursory to earthquakes. We examine the report of Guangmeng and Jie (2013), who claim to have predicted the 2012 M 6.0 earthquake in the Po Valley of northern Italy after seeing a satellite photograph (a digital image) showing a linear-cloud formation over the eastern Apennine Mountains of central Italy. From inspection of 4 years of satellite images we find numerous examples of linear-cloud formations over Italy. A simple test shows no obvious statistical relationship between the occurrence of these cloud formations and earthquakes that occurred in and around Italy. All of the linear-cloud formations we have identified in satellite images, including that which Guangmeng and Jie (2013) claim to have used to predict the 2012 earthquake, appear to be orographic – formed by the interaction of moisture-laden wind flowing over mountains. Guangmeng and Jie (2013) have not clearly stated how linear-cloud formations can be used to predict the size, location, and time of an earthquake, and they have not published an account of all of their predictions (including any unsuccessful predictions). We are skeptical of the validity of the claim by Guangmeng and Jie (2013) that they have managed to predict any earthquakes.
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Hindle, D.; Mackey, K.
2011-02-01
Recorded seismicity from the northwestern Okhotsk plate, northeast Asia, is currently insufficient to account for the predicted slip rates along its boundaries due to plate tectonics. However, the magnitude-frequency relationship for earthquakes from the region suggests that larger earthquakes are possible in the future and that events of ˜Mw 7.5 which should occur every ˜100-350 years would account for almost all the slip of the plate along its boundaries due to Eurasia-North America convergence. We use models for seismic slip distribution along the bounding faults of Okhotsk to conclude that relatively little aseismic strain release is occurring and that larger future earthquakes are likely in the region. Our models broadly support the idea of a single Okhotsk plate, with the large majority of tectonic strain released along its boundaries.
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Understanding dynamic friction through spontaneously evolving laboratory earthquakes.
Rubino, V; Rosakis, A J; Lapusta, N
2017-06-29
Friction plays a key role in how ruptures unzip faults in the Earth's crust and release waves that cause destructive shaking. Yet dynamic friction evolution is one of the biggest uncertainties in earthquake science. Here we report on novel measurements of evolving local friction during spontaneously developing mini-earthquakes in the laboratory, enabled by our ultrahigh speed full-field imaging technique. The technique captures the evolution of displacements, velocities and stresses of dynamic ruptures, whose rupture speed range from sub-Rayleigh to supershear. The observed friction has complex evolution, featuring initial velocity strengthening followed by substantial velocity weakening. Our measurements are consistent with rate-and-state friction formulations supplemented with flash heating but not with widely used slip-weakening friction laws. This study develops a new approach for measuring local evolution of dynamic friction and has important implications for understanding earthquake hazard since laws governing frictional resistance of faults are vital ingredients in physically-based predictive models of the earthquake source.
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Real-time 3-D space numerical shake prediction for earthquake early warning
Wang, Tianyun; Jin, Xing; Huang, Yandan; Wei, Yongxiang
2017-12-01
In earthquake early warning systems, real-time shake prediction through wave propagation simulation is a promising approach. Compared with traditional methods, it does not suffer from the inaccurate estimation of source parameters. For computation efficiency, wave direction is assumed to propagate on the 2-D surface of the earth in these methods. In fact, since the seismic wave propagates in the 3-D sphere of the earth, the 2-D space modeling of wave direction results in inaccurate wave estimation. In this paper, we propose a 3-D space numerical shake prediction method, which simulates the wave propagation in 3-D space using radiative transfer theory, and incorporate data assimilation technique to estimate the distribution of wave energy. 2011 Tohoku earthquake is studied as an example to show the validity of the proposed model. 2-D space model and 3-D space model are compared in this article, and the prediction results show that numerical shake prediction based on 3-D space model can estimate the real-time ground motion precisely, and overprediction is alleviated when using 3-D space model.
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Earthquakes and Earthquake Engineering. LC Science Tracer Bullet.
Buydos, John F., Comp.
An earthquake is a shaking of the ground resulting from a disturbance in the earth's interior. Seismology is the (1) study of earthquakes; (2) origin, propagation, and energy of seismic phenomena; (3) prediction of these phenomena; and (4) investigation of the structure of the earth. Earthquake engineering or engineering seismology includes the…
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Valizadeh Alvan, H.; Mansor, S.; Haydari Azad, F.
2012-12-01
The possibility of earthquake prediction in the frame of several days to few minutes before its occurrence has stirred interest among researchers, recently. Scientists believe that the new theories and explanations of the mechanism of this natural phenomenon are trustable and can be the basis of future prediction efforts. During the last thirty years experimental researches resulted in some pre-earthquake events which are now recognized as confirmed warning signs (precursors) of past known earthquakes. With the advances in in-situ measurement devices and data analysis capabilities and the emergence of satellite-based data collectors, monitoring the earth's surface is now a regular work. Data providers are supplying researchers from all over the world with high quality and validated imagery and non-imagery data. Surface Latent Heat Flux (SLHF) or the amount of energy exchange in the form of water vapor between the earth's surface and atmosphere has been frequently reported as an earthquake precursor during the past years. The accumulated stress in the earth's crust during the preparation phase of earthquakes is said to be the main cause of temperature anomalies weeks to days before the main event and subsequent shakes. Chemical and physical interactions in the presence of underground water lead to higher water evaporation prior to inland earthquakes. On the other hand, the leak of Radon gas occurred as rocks break during earthquake preparation causes the formation of airborne ions and higher Air Temperature (AT) prior to main event. Although co-analysis of direct and indirect observation for precursory events is considered as a promising method for future successful earthquake prediction, without proper and thorough knowledge about the geological setting, atmospheric factors and geodynamics of the earthquake-prone regions we will not be able to identify anomalies due to seismic activity in the earth's crust. Active faulting is a key factor in identification of the
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Roles of Radon-222 and other natural radionuclides in earthquake prediction
International Nuclear Information System (INIS)
Smith, A.R.; Wollenberg, H.A.; Mosier, D.F.
1980-01-01
The concentration of 222 Rn in subsurface waters is one of the natural parameters being investigated to help develop the capability to predict destructive earthquakes. Since 1966, scientists in several nations have sought to link radon variations with ongoing seismic activity, primarily through the dilatancy model for earthquake occurrences. Within the range of these studies, alpha-, beta-, and gamma-radiation detection techniques have been used in both discrete-sampling and continiuous-monitoring programs. These measured techniques are reviewed in terms of instrumentation adapted to seismic-monitoring purposes. A recent Lawrence Berkeley Laboratory study conducted in central California incorporated discrete sampling of wells in the aftershock area of the 1975 Oroville earthquake and continuous monitoring of water radon in a well on the San Andreas Fault. The results presented show short-term radon variations that may be associated with aftershocks and diurnal changes that may reflect earth tidal forces
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Johnston, M.J.S.; Borcherdt, R.D.; Linde, A.T.; Gladwin, M.T.
2006-01-01
Near-field observations of high-precision borehole strain and pore pressure, show no indication of coherent accelerating strain or pore pressure during the weeks to seconds before the 28 September 2004 M 6.0 Parkfield earthquake. Minor changes in strain rate did occur at a few sites during the last 24 hr before the earthquake but these changes are neither significant nor have the form expected for strain during slip coalescence initiating fault failure. Seconds before the event, strain is stable at the 10-11 level. Final prerupture nucleation slip in the hypocentral region is constrained to have a moment less than 2 ?? 1012 N m (M 2.2) and a source size less than 30 m. Ground displacement data indicate similar constraints. Localized rupture nucleation and runaway precludes useful prediction of damaging earthquakes. Coseismic dynamic strains of about 10 microstrain peak-to-peak were superimposed on volumetric strain offsets of about 0.5 microstrain to the northwest of the epicenter and about 0.2 microstrain to the southeast of the epicenter, consistent with right lateral slip. Observed strain and Global Positioning System (GPS) offsets can be simply fit with 20 cm of slip between 4 and 10 km on a 20-km segment of the fault north of Gold Hill (M0 = 7 ?? 1017 N m). Variable slip inversion models using GPS data and seismic data indicate similar moments. Observed postseismic strain is 60% to 300% of the coseismic strain, indicating incomplete release of accumulated strain. No measurable change in fault zone compliance preceding or following the earthquake is indicated by stable earth tidal response. No indications of strain change accompany nonvolcanic tremor events reported prior to and following the earthquake.
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DEFF Research Database (Denmark)
Nielsen, Søren R.K.; Skjærbæk, P. S.; Köylüoglu, H. U.
The paper deals with the prediction of global damage and future structural reliability with special emphasis on sensitivity, bias and uncertainty of these predictions dependent on the statistically equivalent realizations of the future earthquake. The predictions are based on a modified Clough......-Johnston single-degree-of-freedom (SDOF) oscillator with three parameters which are calibrated to fit the displacement response and the damage development in the past earthquake....
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Predicting earthquakes by analyzing accelerating precursory seismic activity
Varnes, D.J.
1989-01-01
During 11 sequences of earthquakes that in retrospect can be classed as foreshocks, the accelerating rate at which seismic moment is released follows, at least in part, a simple equation. This equation (1) is {Mathematical expression},where {Mathematical expression} is the cumulative sum until time, t, of the square roots of seismic moments of individual foreshocks computed from reported magnitudes;C and n are constants; and tfis a limiting time at which the rate of seismic moment accumulation becomes infinite. The possible time of a major foreshock or main shock, tf,is found by the best fit of equation (1), or its integral, to step-like plots of {Mathematical expression} versus time using successive estimates of tfin linearized regressions until the maximum coefficient of determination, r2,is obtained. Analyzed examples include sequences preceding earthquakes at Cremasta, Greece, 2/5/66; Haicheng, China 2/4/75; Oaxaca, Mexico, 11/29/78; Petatlan, Mexico, 3/14/79; and Central Chile, 3/3/85. In 29 estimates of main-shock time, made as the sequences developed, the errors in 20 were less than one-half and in 9 less than one tenth the time remaining between the time of the last data used and the main shock. Some precursory sequences, or parts of them, yield no solution. Two sequences appear to include in their first parts the aftershocks of a previous event; plots using the integral of equation (1) show that the sequences are easily separable into aftershock and foreshock segments. Synthetic seismic sequences of shocks at equal time intervals were constructed to follow equation (1), using four values of n. In each series the resulting distributions of magnitudes closely follow the linear Gutenberg-Richter relation log N=a-bM, and the product n times b for each series is the same constant. In various forms and for decades, equation (1) has been used successfully to predict failure times of stressed metals and ceramics, landslides in soil and rock slopes, and volcanic
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WHY WE CANNOT PREDICT STRONG EARTHQUAKES IN THE EARTH’S CRUST
Directory of Open Access Journals (Sweden)
Iosif L. Gufeld
2011-01-01
Full Text Available In the past decade, earthquake disasters caused multiple fatalities and significant economic losses and challenged the modern civilization. The wellknown achievements and growing power of civilization are backstrapped when facing the Nature. The question arises, what hinders solving a problem of earthquake prediction, while longterm and continuous seismic monitoring systems are in place in many regions of the world. For instance, there was no forecast of the Japan Great Earthquake of March 11, 2011, despite the fact that monitoring conditions for its prediction were unique. Its focal zone was 100–200 km away from the monitoring network installed in the area of permanent seismic hazard, which is subject to nonstop and longterm seismic monitoring. Lesson should be learned from our common fiasco in forecasting, taking into account research results obtained during the past 50–60 years. It is now evident that we failed to identify precursors of the earthquakes. Prior to the earthquake occurrence, the observed local anomalies of various fields reflected other processes that were mistakenly viewed as processes of preparation for largescale faulting. For many years, geotectonic situations were analyzed on the basis of the physics of destruction of laboratory specimens, which was applied to the lithospheric conditions. Many researchers realize that such an approach is inaccurate. Nonetheless, persistent attempts are being undertaken with application of modern computation to detect anomalies of various fields, which may be interpreted as earthquake precursors. In our opinion, such illusory intentions were smashed by the Great Japan Earthquake (Figure 6. It is also obvious that sufficient attention has not been given yet to fundamental studies of seismic processes.This review presents the authors’ opinion concerning the origin of the seismic process and strong earthquakes, being part of the process. The authors realize that a wide discussion is
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CSEP-Japan: The Japanese node of the collaboratory for the study of earthquake predictability
Yokoi, S.; Tsuruoka, H.; Nanjo, K.; Hirata, N.
2011-12-01
Collaboratory for the Study of Earthquake Predictability (CSEP) is a global project of earthquake predictability research. The final goal of this project is to have a look for the intrinsic predictability of the earthquake rupture process through forecast testing experiments. The Earthquake Research Institute, the University of Tokyo joined the CSEP and started the Japanese testing center called as CSEP-Japan. This testing center constitutes an open access to researchers contributing earthquake forecast models for applied to Japan. A total of 91 earthquake forecast models were submitted on the prospective experiment starting from 1 November 2009. The models are separated into 4 testing classes (1 day, 3 months, 1 year and 3 years) and 3 testing regions covering an area of Japan including sea area, Japanese mainland and Kanto district. We evaluate the performance of the models in the official suite of tests defined by the CSEP. The experiments of 1-day, 3-month, 1-year and 3-year forecasting classes were implemented for 92 rounds, 4 rounds, 1round and 0 round (now in progress), respectively. The results of the 3-month class gave us new knowledge concerning statistical forecasting models. All models showed a good performance for magnitude forecasting. On the other hand, observation is hardly consistent in space-distribution with most models in some cases where many earthquakes occurred at the same spot. Throughout the experiment, it has been clarified that some properties of the CSEP's evaluation tests such as the L-test show strong correlation with the N-test. We are now processing to own (cyber-) infrastructure to support the forecast experiment as follows. (1) Japanese seismicity has changed since the 2011 Tohoku earthquake. The 3rd call for forecasting models was announced in order to promote model improvement for forecasting earthquakes after this earthquake. So, we provide Japanese seismicity catalog maintained by JMA for modelers to study how seismicity
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Earthquakes: no danger for deep underground nuclear waste repositories
International Nuclear Information System (INIS)
2010-03-01
On the Earth, the continental plates are steadily moving. Principally at the plate boundaries such shifts produce stresses which are released in form of earthquakes. The highest the built-up energy, the more violent will be the shaking. Earthquakes accompany mankind from very ancient times on and they disturb the population. Till now nobody is able to predict where and when they will take place. But on the Earth there are regions where, due to their geological situation, the occurrence of earthquakes is more probable than elsewhere. The impact of a very strong earthquake on the structures at the Earth surface depends on several factors. Besides the ground structure, the density of buildings, construction style and materials used play an important role. Construction-related technical measures can improve the safety of buildings and, together with a correct behaviour of the people concerned, save many lives. Earthquakes are well known in Switzerland. Here, the stresses are due to the collision of the African and European continental plates that created the Alps. The impact of earthquake is more limited in the underground than at the Earth surface. There is no danger for deep underground repositories
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A global earthquake discrimination scheme to optimize ground-motion prediction equation selection
Garcia, Daniel; Wald, David J.; Hearne, Michael
2012-01-01
We present a new automatic earthquake discrimination procedure to determine in near-real time the tectonic regime and seismotectonic domain of an earthquake, its most likely source type, and the corresponding ground-motion prediction equation (GMPE) class to be used in the U.S. Geological Survey (USGS) Global ShakeMap system. This method makes use of the Flinn–Engdahl regionalization scheme, seismotectonic information (plate boundaries, global geology, seismicity catalogs, and regional and local studies), and the source parameters available from the USGS National Earthquake Information Center in the minutes following an earthquake to give the best estimation of the setting and mechanism of the event. Depending on the tectonic setting, additional criteria based on hypocentral depth, style of faulting, and regional seismicity may be applied. For subduction zones, these criteria include the use of focal mechanism information and detailed interface models to discriminate among outer-rise, upper-plate, interface, and intraslab seismicity. The scheme is validated against a large database of recent historical earthquakes. Though developed to assess GMPE selection in Global ShakeMap operations, we anticipate a variety of uses for this strategy, from real-time processing systems to any analysis involving tectonic classification of sources from seismic catalogs.
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Predictability of Landslide Timing From Quasi-Periodic Precursory Earthquakes
Bell, Andrew F.
2018-02-01
Accelerating rates of geophysical signals are observed before a range of material failure phenomena. They provide insights into the physical processes controlling failure and the basis for failure forecasts. However, examples of accelerating seismicity before landslides are rare, and their behavior and forecasting potential are largely unknown. Here I use a Bayesian methodology to apply a novel gamma point process model to investigate a sequence of quasiperiodic repeating earthquakes preceding a large landslide at Nuugaatsiaq in Greenland in June 2017. The evolution in earthquake rate is best explained by an inverse power law increase with time toward failure, as predicted by material failure theory. However, the commonly accepted power law exponent value of 1.0 is inconsistent with the data. Instead, the mean posterior value of 0.71 indicates a particularly rapid acceleration toward failure and suggests that only relatively short warning times may be possible for similar landslides in future.
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Time-predictable model applicability for earthquake occurrence in northeast India and vicinity
Directory of Open Access Journals (Sweden)
A. Panthi
2011-03-01
Full Text Available Northeast India and its vicinity is one of the seismically most active regions in the world, where a few large and several moderate earthquakes have occurred in the past. In this study the region of northeast India has been considered for an earthquake generation model using earthquake data as reported by earthquake catalogues National Geophysical Data Centre, National Earthquake Information Centre, United States Geological Survey and from book prepared by Gupta et al. (1986 for the period 1906–2008. The events having a surface wave magnitude of Ms≥5.5 were considered for statistical analysis. In this region, nineteen seismogenic sources were identified by the observation of clustering of earthquakes. It is observed that the time interval between the two consecutive mainshocks depends upon the preceding mainshock magnitude (Mp and not on the following mainshock (Mf. This result corroborates the validity of time-predictable model in northeast India and its adjoining regions. A linear relation between the logarithm of repeat time (T of two consecutive events and the magnitude of the preceding mainshock is established in the form LogT = cMp+a, where "c" is a positive slope of line and "a" is function of minimum magnitude of the earthquake considered. The values of the parameters "c" and "a" are estimated to be 0.21 and 0.35 in northeast India and its adjoining regions. The less value of c than the average implies that the earthquake occurrence in this region is different from those of plate boundaries. The result derived can be used for long term seismic hazard estimation in the delineated seismogenic regions.
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Directory of Open Access Journals (Sweden)
Suryanita Reni
2017-01-01
Full Text Available The strong motion earthquake could cause the building damage in case of the building not considered in the earthquake design of the building. The study aims to predict the damage-level of building due to earthquake using Artificial Neural Networks method. The building model is a reinforced concrete building with ten floors and height between floors is 3.6 m. The model building received a load of the earthquake based on nine earthquake time history records. Each time history scaled to 0,5g, 0,75g, and 1,0g. The Artificial Neural Networks are designed in 4 architectural models using the MATLAB program. Model 1 used the displacement, velocity, and acceleration as input and Model 2 used the displacement only as the input. Model 3 used the velocity as input, and Model 4 used the acceleration just as input. The output of the Neural Networks is the damage level of the building with the category of Safe (1, Immediate Occupancy (2, Life Safety (3 or in a condition of Collapse Prevention (4. According to the results, Neural Network models have the prediction rate of the damage level between 85%-95%. Therefore, one of the solutions for analyzing the structural responses and the damage level promptly and efficiently when the earthquake occurred is by using Artificial Neural Network
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Gambling score in earthquake prediction analysis
Molchan, G.; Romashkova, L.
2011-03-01
The number of successes and the space-time alarm rate are commonly used to characterize the strength of an earthquake prediction method and the significance of prediction results. It has been recently suggested to use a new characteristic to evaluate the forecaster's skill, the gambling score (GS), which incorporates the difficulty of guessing each target event by using different weights for different alarms. We expand parametrization of the GS and use the M8 prediction algorithm to illustrate difficulties of the new approach in the analysis of the prediction significance. We show that the level of significance strongly depends (1) on the choice of alarm weights, (2) on the partitioning of the entire alarm volume into component parts and (3) on the accuracy of the spatial rate measure of target events. These tools are at the disposal of the researcher and can affect the significance estimate. Formally, all reasonable GSs discussed here corroborate that the M8 method is non-trivial in the prediction of 8.0 ≤M < 8.5 events because the point estimates of the significance are in the range 0.5-5 per cent. However, the conservative estimate 3.7 per cent based on the number of successes seems preferable owing to two circumstances: (1) it is based on relative values of the spatial rate and hence is more stable and (2) the statistic of successes enables us to construct analytically an upper estimate of the significance taking into account the uncertainty of the spatial rate measure.
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International Nuclear Information System (INIS)
Mishima, J.; Ayer, J.E.; Hays, I.D.
1980-12-01
This report estimates the potential airborne releases of plutonium as a consequence of various severities of earthquake and wind hazard postulated for the 102 Building at the General Electric Vallecitos Nuclear Center in California. The releases are based on damage scenarios developed by other specialists. The hazard severities presented range up to a nominal velocity of 230 mph for wind hazard and are in excess of 0.8 g linear acceleration for earthquakes. The consequences of thrust faulting are considered. The approaches and factors used to estimate the releases are discussed. Release estimates range from 0.003 to 3 g Pu
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Directory of Open Access Journals (Sweden)
Junjie Ren
2013-01-01
Full Text Available Recurrence interval of large earthquake on an active fault zone is an important parameter in assessing seismic hazard. The 2008 Wenchuan earthquake (Mw 7.9 occurred on the central Longmen Shan fault zone and ruptured the Yingxiu-Beichuan fault (YBF and the Guanxian-Jiangyou fault (GJF. However, there is a considerable discrepancy among recurrence intervals of large earthquake in preseismic and postseismic estimates based on slip rate and paleoseismologic results. Post-seismic trenches showed that the central Longmen Shan fault zone probably undertakes an event similar to the 2008 quake, suggesting a characteristic earthquake model. In this paper, we use the published seismogenic model of the 2008 earthquake based on Global Positioning System (GPS and Interferometric Synthetic Aperture Radar (InSAR data and construct a characteristic seismic moment accumulation/release model to estimate recurrence interval of large earthquakes on the central Longmen Shan fault zone. Our results show that the seismogenic zone accommodates a moment rate of (2.7 ± 0.3 × 1017 N m/yr, and a recurrence interval of 3900 ± 400 yrs is necessary for accumulation of strain energy equivalent to the 2008 earthquake. This study provides a preferred interval estimation of large earthquakes for seismic hazard analysis in the Longmen Shan region.
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Ren, Junjie; Zhang, Shimin
2013-01-01
Recurrence interval of large earthquake on an active fault zone is an important parameter in assessing seismic hazard. The 2008 Wenchuan earthquake (Mw 7.9) occurred on the central Longmen Shan fault zone and ruptured the Yingxiu-Beichuan fault (YBF) and the Guanxian-Jiangyou fault (GJF). However, there is a considerable discrepancy among recurrence intervals of large earthquake in preseismic and postseismic estimates based on slip rate and paleoseismologic results. Post-seismic trenches showed that the central Longmen Shan fault zone probably undertakes an event similar to the 2008 quake, suggesting a characteristic earthquake model. In this paper, we use the published seismogenic model of the 2008 earthquake based on Global Positioning System (GPS) and Interferometric Synthetic Aperture Radar (InSAR) data and construct a characteristic seismic moment accumulation/release model to estimate recurrence interval of large earthquakes on the central Longmen Shan fault zone. Our results show that the seismogenic zone accommodates a moment rate of (2.7 ± 0.3) × 10¹⁷ N m/yr, and a recurrence interval of 3900 ± 400 yrs is necessary for accumulation of strain energy equivalent to the 2008 earthquake. This study provides a preferred interval estimation of large earthquakes for seismic hazard analysis in the Longmen Shan region.
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International Nuclear Information System (INIS)
Moldoveanu, C.L.; Novikova, O.V.; Panza, G.F.; Radulian, M.
2003-06-01
The preparation process of the strong subcrustal events originating in Vrancea region, Romania, is monitored using an intermediate-term medium-range earthquake prediction method - the CN algorithm (Keilis-Borok and Rotwain, 1990). We present the results of the monitoring of the preparation of future strong earthquakes for the time interval from January 1, 1994 (1994.1.1), to January 1, 2003 (2003.1.1) using the updated catalogue of the Romanian local network. The database considered for the CN monitoring of the preparation of future strong earthquakes in Vrancea covers the period from 1966.3.1 to 2003.1.1 and the geographical rectangle 44.8 deg - 48.4 deg N, 25.0 deg - 28.0 deg E. The algorithm correctly identifies, by retrospective prediction, the TJPs for all the three strong earthquakes (Mo=6.4) that occurred in Vrancea during this period. The cumulated duration of the TIPs represents 26.5% of the total period of time considered (1966.3.1-2003.1.1). The monitoring of current seismicity using the algorithm CN has been carried out since 1994. No strong earthquakes occurred from 1994.1.1 to 2003.1.1 but the CN declared an extended false alarm from 1999.5.1 to 2000.11.1. No alarm has currently been declared in the region (on January 1, 2003), as can be seen from the TJPs diagram shown. (author)
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The 2012 Mw5.6 earthquake in Sofia seismogenic zone - is it a slow earthquake
Raykova, Plamena; Solakov, Dimcho; Slavcheva, Krasimira; Simeonova, Stela; Aleksandrova, Irena
2017-04-01
Recently our understanding of tectonic faulting has been shaken by the discoveries of seismic tremor, low frequency earthquakes, slow slip events, and other models of fault slip. These phenomenas represent models of failure that were thought to be non-existent and theoretically impossible only a few years ago. Slow earthquakes are seismic phenomena in which the rupture of geological faults in the earth's crust occurs gradually without creating strong tremors. Despite the growing number of observations of slow earthquakes their origin remains unresolved. Studies show that the duration of slow earthquakes ranges from a few seconds to a few hundred seconds. The regular earthquakes with which most people are familiar release a burst of built-up stress in seconds, slow earthquakes release energy in ways that do little damage. This study focus on the characteristics of the Mw5.6 earthquake occurred in Sofia seismic zone on May 22nd, 2012. The Sofia area is the most populated, industrial and cultural region of Bulgaria that faces considerable earthquake risk. The Sofia seismic zone is located in South-western Bulgaria - the area with pronounce tectonic activity and proved crustal movement. In 19th century the city of Sofia (situated in the centre of the Sofia seismic zone) has experienced two strong earthquakes with epicentral intensity of 10 MSK. During the 20th century the strongest event occurred in the vicinity of the city of Sofia is the 1917 earthquake with MS=5.3 (I0=7-8 MSK64).The 2012 quake occurs in an area characterized by a long quiescence (of 95 years) for moderate events. Moreover, a reduced number of small earthquakes have also been registered in the recent past. The Mw5.6 earthquake is largely felt on the territory of Bulgaria and neighbouring countries. No casualties and severe injuries have been reported. Mostly moderate damages were observed in the cities of Pernik and Sofia and their surroundings. These observations could be assumed indicative for a
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Singh, R. P.; Ahmad, R.
2015-12-01
A comparison of recent observed ground motion parameters of recent Gorkha Nepal earthquake of 25 April 2015 (Mw 7.8) with the predicted ground motion parameters using exitsing attenuation relation of the Himalayan region will be presented. The recent earthquake took about 8000 lives and destroyed thousands of poor quality of buildings and the earthquake was felt by millions of people living in Nepal, China, India, Bangladesh, and Bhutan. The knowledge of ground parameters are very important in developing seismic code of seismic prone regions like Himalaya for better design of buildings. The ground parameters recorded in recent earthquake event and aftershocks are compared with attenuation relations for the Himalayan region, the predicted ground motion parameters show good correlation with the observed ground parameters. The results will be of great use to Civil engineers in updating existing building codes in the Himlayan and surrounding regions and also for the evaluation of seismic hazards. The results clearly show that the attenuation relation developed for the Himalayan region should be only used, other attenuation relations based on other regions fail to provide good estimate of observed ground motion parameters.
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Prediction of site specific ground motion for large earthquake
International Nuclear Information System (INIS)
Kamae, Katsuhiro; Irikura, Kojiro; Fukuchi, Yasunaga.
1990-01-01
In this paper, we apply the semi-empirical synthesis method by IRIKURA (1983, 1986) to the estimation of site specific ground motion using accelerograms observed at Kumatori in Osaka prefecture. Target earthquakes used here are a comparatively distant earthquake (Δ=95 km, M=5.6) caused by the YAMASAKI fault and a near earthquake (Δ=27 km, M=5.6). The results obtained are as follows. 1) The accelerograms from the distant earthquake (M=5.6) are synthesized using the aftershock records (M=4.3) for 1983 YAMASAKI fault earthquake whose source parameters have been obtained by other authors from the hypocentral distribution of the aftershocks. The resultant synthetic motions show a good agreement with the observed ones. 2) The synthesis for a near earthquake (M=5.6, we call this target earthquake) are made using a small earthquake which occurred in the neighborhood of the target earthquake. Here, we apply two methods for giving the parameters for synthesis. One method is to use the parameters of YAMASAKI fault earthquake which has the same magnitude as the target earthquake, and the other is to use the parameters obtained from several existing empirical formulas. The resultant synthetic motion with the former parameters shows a good agreement with the observed one, but that with the latter does not. 3) We estimate the source parameters from the source spectra of several earthquakes which have been observed in this site. Consequently we find that the small earthquakes (M<4) as Green's functions should be carefully used because the stress drops are not constant. 4) We propose that we should designate not only the magnitudes but also seismic moments of the target earthquake and the small earthquake. (J.P.N.)
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Comparison of FISGAS swelling and gas release predictions with experiment
International Nuclear Information System (INIS)
Ostensen, R.W.
1979-01-01
FISGAS calculations were compared to fuel swelling data from the FD1 tests and to gas release data from the FGR39 test. Late swelling and gas release predictions are satisfactory if vacancy depletion effects are added to the code. However, early swelling predictions are not satisfactory, and early gas release predictions are very poor. Explanation of these discrepancies is speculative
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Modeling of fission product release in integral codes
International Nuclear Information System (INIS)
Obaidurrahman, K.; Raman, Rupak K.; Gaikwad, Avinash J.
2014-01-01
The Great Tohoku earthquake and tsunami that stroke the Fukushima-Daiichi nuclear power station in March 11, 2011 has intensified the needs of detailed nuclear safety research and with this objective all streams associated with severe accident phenomenology are being revisited thoroughly. The present paper would cover an overview of state of art FP release models being used, the important phenomenon considered in semi-mechanistic models and knowledge gaps in present FP release modeling. Capability of FP release module, ELSA of ASTEC integral code in appropriate prediction of FP release under several diversified core degraded conditions will also be demonstrated. Use of semi-mechanistic fission product release models at AERB in source-term estimation shall be briefed. (author)
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Baltay, A.; Hanks, T. C.; Vernon, F.
2016-12-01
We illustrate two essential consequences of the systematic difference between moment magnitude and local magnitude for small earthquakes, illuminating the underlying earthquake physics. Moment magnitude, M 2/3 log M0, is uniformly valid for all earthquake sizes [Hanks and Kanamori, 1979]. However, the relationship between local magnitude ML and moment is itself magnitude dependent. For moderate events, 3> fmax. Just as importantly, if this relation is overlooked, prediction of large-magnitude ground motion from small earthquakes will be misguided. We also consider the effect of this magnitude scale difference on b-value. The oft-cited b-value of 1 should hold for small magnitudes, given M. Use of ML necessitates b=2/3 for the same data set; use of mixed, or unknown, magnitudes complicates the matter further. This is of particular import when estimating the rate of large earthquakes when one has limited data on their recurrence, as is the case for induced earthquakes in the central US.
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Earthquake prediction research with plastic nuclear track detectors
International Nuclear Information System (INIS)
Woith, H.; Enge, W.; Beaujean, R.; Oschlies, K.
1988-01-01
Since 1984 a German-Turkish project on earthquake prediction research has been operating at the North Anatolian fault zone in Turkey. Among many other parameters changes in Radon emission have also been investigated. Plastic nuclear track detectors (Kodak cellulose nitrate LR 115) are used to record alpha-particles emitted from Radon and Thoron atoms and their daughter isotopes. The detectors are replaced and analyzed every 3 weeks. Thus a quasi-continuous time sequence of the Radon soil gas emission is recorded. We present a comparison between measurements made with electronic counters and plastic track detectors. (author)
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Asencio-Cortés, G.; Morales-Esteban, A.; Shang, X.; Martínez-Álvarez, F.
2018-06-01
Earthquake magnitude prediction is a challenging problem that has been widely studied during the last decades. Statistical, geophysical and machine learning approaches can be found in literature, with no particularly satisfactory results. In recent years, powerful computational techniques to analyze big data have emerged, making possible the analysis of massive datasets. These new methods make use of physical resources like cloud based architectures. California is known for being one of the regions with highest seismic activity in the world and many data are available. In this work, the use of several regression algorithms combined with ensemble learning is explored in the context of big data (1 GB catalog is used), in order to predict earthquakes magnitude within the next seven days. Apache Spark framework, H2 O library in R language and Amazon cloud infrastructure were been used, reporting very promising results.
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,
1997-01-01
The severity of an earthquake can be expressed in terms of both intensity and magnitude. However, the two terms are quite different, and they are often confused. Intensity is based on the observed effects of ground shaking on people, buildings, and natural features. It varies from place to place within the disturbed region depending on the location of the observer with respect to the earthquake epicenter. Magnitude is related to the amount of seismic energy released at the hypocenter of the earthquake. It is based on the amplitude of the earthquake waves recorded on instruments
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Clustered and transient earthquake sequences in mid-continents
Liu, M.; Stein, S. A.; Wang, H.; Luo, G.
2012-12-01
Earthquakes result from sudden release of strain energy on faults. On plate boundary faults, strain energy is constantly accumulating from steady and relatively rapid relative plate motion, so large earthquakes continue to occur so long as motion continues on the boundary. In contrast, such steady accumulation of stain energy does not occur on faults in mid-continents, because the far-field tectonic loading is not steadily distributed between faults, and because stress perturbations from complex fault interactions and other stress triggers can be significant relative to the slow tectonic stressing. Consequently, mid-continental earthquakes are often temporally clustered and transient, and spatially migrating. This behavior is well illustrated by large earthquakes in North China in the past two millennia, during which no single large earthquakes repeated on the same fault segments, but moment release between large fault systems was complementary. Slow tectonic loading in mid-continents also causes long aftershock sequences. We show that the recent small earthquakes in the Tangshan region of North China are aftershocks of the 1976 Tangshan earthquake (M 7.5), rather than indicators of a new phase of seismic activity in North China, as many fear. Understanding the transient behavior of mid-continental earthquakes has important implications for assessing earthquake hazards. The sequence of large earthquakes in the New Madrid Seismic Zone (NMSZ) in central US, which includes a cluster of M~7 events in 1811-1812 and perhaps a few similar ones in the past millennium, is likely a transient process, releasing previously accumulated elastic strain on recently activated faults. If so, this earthquake sequence will eventually end. Using simple analysis and numerical modeling, we show that the large NMSZ earthquakes may be ending now or in the near future.
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Predicting Dynamic Response of Structures under Earthquake Loads Using Logical Analysis of Data
Directory of Open Access Journals (Sweden)
Ayman Abd-Elhamed
2018-04-01
Full Text Available In this paper, logical analysis of data (LAD is used to predict the seismic response of building structures employing the captured dynamic responses. In order to prepare the data, computational simulations using a single degree of freedom (SDOF building model under different ground motion records are carried out. The selected excitation records are real and of different peak ground accelerations (PGA. The sensitivity of the seismic response in terms of displacements of floors to the variation in earthquake characteristics, such as soil class, characteristic period, and time step of records, peak ground displacement, and peak ground velocity, have also been considered. The dynamic equation of motion describing the building model and the applied earthquake load are presented and solved incrementally using the Runge-Kutta method. LAD then finds the characteristic patterns which lead to forecast the seismic response of building structures. The accuracy of LAD is compared to that of an artificial neural network (ANN, since the latter is the most known machine learning technique. Based on the conducted study, the proposed LAD model has been proven to be an efficient technique to learn, simulate, and blindly predict the dynamic response behaviour of building structures subjected to earthquake loads.
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Extreme value distribution of earthquake magnitude
Zi, Jun Gan; Tung, C. C.
1983-07-01
Probability distribution of maximum earthquake magnitude is first derived for an unspecified probability distribution of earthquake magnitude. A model for energy release of large earthquakes, similar to that of Adler-Lomnitz and Lomnitz, is introduced from which the probability distribution of earthquake magnitude is obtained. An extensive set of world data for shallow earthquakes, covering the period from 1904 to 1980, is used to determine the parameters of the probability distribution of maximum earthquake magnitude. Because of the special form of probability distribution of earthquake magnitude, a simple iterative scheme is devised to facilitate the estimation of these parameters by the method of least-squares. The agreement between the empirical and derived probability distributions of maximum earthquake magnitude is excellent.
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Energy Technology Data Exchange (ETDEWEB)
Men, Ke-Pei [Nanjing Univ. of Information Science and Technology (China). College of Mathematics and Statistics; Cui, Lei [California Univ., Santa Barbara, CA (United States). Applied Probability and Statistics Dept.
2013-05-15
The the Jiangsu-South Yellow Sea region is one of the key seismic monitoring defence areas in the eastern part of China. Since 1846, M {>=} 6 strong earthquakes have showed an obvious commensurability and orderliness in this region. The main orderly values are 74 {proportional_to} 75 a, 57 {proportional_to} 58 a, 11 {proportional_to} 12 a, and 5 {proportional_to} 6 a, wherein 74 {proportional_to} 75 a and 57 {proportional_to} 58 a with an outstanding predictive role. According to the information prediction theory of Wen-Bo Weng, we conceived the M {>=} 6 strong earthquake ordered network structure in the South Yellow Sea and the whole region. Based on this, we analyzed and discussed the variation of seismicity in detail and also made a trend prediction of M {>=} 6 strong earthquakes in the future. The results showed that since 1998 it has entered into a new quiet episode which may continue until about 2042; and the first M {>=} 6 strong earthquake in the next active episode will probably occur in 2053 pre and post, with the location likely in the sea area of the South Yellow Sea; also, the second and the third ones or strong earthquake swarm in the future will probably occur in 2058 and 2070 pre and post. (orig.)
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Scaling and spatial complementarity of tectonic earthquake swarms
Passarelli, Luigi
2017-11-10
Tectonic earthquake swarms (TES) often coincide with aseismic slip and sometimes precede damaging earthquakes. In spite of recent progress in understanding the significance and properties of TES at plate boundaries, their mechanics and scaling are still largely uncertain. Here we evaluate several TES that occurred during the past 20 years on a transform plate boundary in North Iceland. We show that the swarms complement each other spatially with later swarms discouraged from fault segments activated by earlier swarms, which suggests efficient strain release and aseismic slip. The fault area illuminated by earthquakes during swarms may be more representative of the total moment release than the cumulative moment of the swarm earthquakes. We use these findings and other published results from a variety of tectonic settings to discuss general scaling properties for TES. The results indicate that the importance of TES in releasing tectonic strain at plate boundaries may have been underestimated.
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Ferraes, Sergio G.
1992-06-01
A predictive equation to estimate the next interoccurrence time (τ) for the next earthquake ( M≥6) in the Ometepec segment is presented, based on Bayes' theorem and the Gaussian process. Bayes' theorem is used to relate the Gaussian process to both a log-normal distribution of recurrence times (τ) and a log-normal distribution of magnitudes ( M) ( Nishenko and Buland, 1987; Lomnitz, 1964). We constructed two new random variables X=In M and Y=In τ with normal marginal densities, and based on the Gaussian process model we assume that their joint density is normal. Using this information, we determine the Bayesian conditional probability. Finally, a predictive equation is derived, based on the criterion of maximization of the Bayesian conditional probability. The model forecasts the next interoccurrence time, conditional on the magnitude of the last event. Realistic estimates of future damaging earthquakes are based on relocated historical earthquakes. However, at the present time there is a controversy between Nishenko-Singh and Gonzalez-Ruiz-Mc-Nally concerning the rupturing process of the 1907 earthquake. We use our Bayesian analysis to examine and discuss this very important controversy. To clarify to the full significance of the analysis, we put forward the results using two catalogues: (1) The Ometepec catalogue without the 1907 earthquake (González-Ruíz-McNally), and (2) the Ometepec catalogue including the 1907 earthquake (Nishenko-Singh). The comparison of the prediction error reveals that in the Nishenko-Singh catalogue, the errors are considerably smaller than the average error for the González-Ruíz-McNally catalogue of relocated events. Finally, using the Nishenko-Singh catalogue which locates the 1907 event inside the Ometepec segment, we conclude that the next expected damaging earthquake ( M≥6.0) will occur approximately within the next time interval τ=11.82 years from the last event (which occurred on July 2, 1984), or equivalently will
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Near-fault earthquake ground motion prediction by a high-performance spectral element numerical code
International Nuclear Information System (INIS)
Paolucci, Roberto; Stupazzini, Marco
2008-01-01
Near-fault effects have been widely recognised to produce specific features of earthquake ground motion, that cannot be reliably predicted by 1D seismic wave propagation modelling, used as a standard in engineering applications. These features may have a relevant impact on the structural response, especially in the nonlinear range, that is hard to predict and to be put in a design format, due to the scarcity of significant earthquake records and of reliable numerical simulations. In this contribution a pilot study is presented for the evaluation of seismic ground-motions in the near-fault region, based on a high-performance numerical code for 3D seismic wave propagation analyses, including the seismic fault, the wave propagation path and the near-surface geological or topographical irregularity. For this purpose, the software package GeoELSE is adopted, based on the spectral element method. The set-up of the numerical benchmark of 3D ground motion simulation in the valley of Grenoble (French Alps) is chosen to study the effect of the complex interaction between basin geometry and radiation mechanism on the variability of earthquake ground motion
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Earthquakes: hydrogeochemical precursors
Ingebritsen, Steven E.; Manga, Michael
2014-01-01
Earthquake prediction is a long-sought goal. Changes in groundwater chemistry before earthquakes in Iceland highlight a potential hydrogeochemical precursor, but such signals must be evaluated in the context of long-term, multiparametric data sets.
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Inelastic spectra to predict period elongation of structures under earthquake loading
DEFF Research Database (Denmark)
Katsanos, Evangelos; Sextos, A.G.
2015-01-01
Period lengthening, exhibited by structures when subjected to strong ground motions, constitutes an implicit proxy of structural inelasticity and associated damage. However, the reliable prediction of the inelastic period is tedious and a multi-parametric task, which is related to both epistemic ...... for period lengthening as a function of Ry and Tel. These equations may be used in the framework of the earthquake record selection and scaling....
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Combining multiple earthquake models in real time for earthquake early warning
Minson, Sarah E.; Wu, Stephen; Beck, James L; Heaton, Thomas H.
2017-01-01
The ultimate goal of earthquake early warning (EEW) is to provide local shaking information to users before the strong shaking from an earthquake reaches their location. This is accomplished by operating one or more real‐time analyses that attempt to predict shaking intensity, often by estimating the earthquake’s location and magnitude and then predicting the ground motion from that point source. Other EEW algorithms use finite rupture models or may directly estimate ground motion without first solving for an earthquake source. EEW performance could be improved if the information from these diverse and independent prediction models could be combined into one unified, ground‐motion prediction. In this article, we set the forecast shaking at each location as the common ground to combine all these predictions and introduce a Bayesian approach to creating better ground‐motion predictions. We also describe how this methodology could be used to build a new generation of EEW systems that provide optimal decisions customized for each user based on the user’s individual false‐alarm tolerance and the time necessary for that user to react.
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Directory of Open Access Journals (Sweden)
A. A. Heidari
2015-12-01
Full Text Available Earthquake can pose earth-shattering health hazards to the natural slops and land infrastructures. One of the chief consequences of the earthquakes can be land sliding, which is instigated by durable shaking. In this research, an efficient procedure is proposed to assist the prediction of earthquake-originated slope displacements (EIDS. New hybrid SVM-CBBO strategy is implemented to predict the EIDS. For this purpose, first, chaos paradigm is combined with initialization of BBO to enhance the diversification and intensification capacity of the conventional BBO optimizer. Then, chaotic BBO is developed as the searching scheme to investigate the best values of SVR parameters. In this paper, it will be confirmed that how the new computing approach is effective in prediction of EIDS. The outcomes affirm that the SVR-BBO strategy with chaos can be employed effectively as a predicting tool for evaluating the EIDS.
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A Trial for Earthquake Prediction by Precise Monitoring of Deep Ground Water Temperature
Nasuhara, Y.; Otsuki, K.; Yamauchi, T.
2006-12-01
A near future large earthquake is estimated to occur off Miyagi prefecture, northeast Japan within 20 years at a probability of about 80 %. In order to predict this earthquake, we have observed groundwater temperature in a borehole at Sendai city 100 km west of the asperity. This borehole penetrates the fault zone of NE-trending active reverse fault, Nagamachi-Rifu fault zone, at 820m depth. Our concept of the ground water observation is that fault zones are natural amplifier of crustal strain, and hence at 820m depth we set a very precise quartz temperature sensor with the resolution of 0.0002 deg. C. We confirmed our observation system to work normally by both the pumping up tests and the systematic temperature changes at different depths. Since the observation started on June 20 in 2004, we found mysterious intermittent temperature fluctuations of two types; one is of a period of 5-10 days and an amplitude of ca. 0.1 deg. C, and the other is of a period of 11-21 days and an amplitude of ca. 0.2 deg. C. Based on the examination using the product of Grashof number and Prantl number, natural convection of water can be occurred in the borehole. However, since these temperature fluctuations are observed only at the depth around 820 m, thus it is likely that they represent the hydrological natures proper to the Nagamachi-Rifu fault zone. It is noteworthy that the small temperature changes correlatable with earth tide are superposed on the long term and large amplitude fluctuations. The amplitude on the days of the full moon and new moon is ca. 0.001 deg. C. The bottoms of these temperature fluctuations always delay about 6 hours relative to peaks of earth tide. This is interpreted as that water in the borehole is sucked into the fault zone on which tensional normal stress acts on the days of the full moon and new moon. The amplitude of the crustal strain by earth tide was measured at ca. 2∗10^-8 strain near our observation site. High frequency temperature noise of
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Underground water stress release models
Li, Yong; Dang, Shenjun; Lü, Shaochuan
2011-08-01
The accumulation of tectonic stress may cause earthquakes at some epochs. However, in most cases, it leads to crustal deformations. Underground water level is a sensitive indication of the crustal deformations. We incorporate the information of the underground water level into the stress release models (SRM), and obtain the underground water stress release model (USRM). We apply USRM to the earthquakes occurred at Tangshan region. The analysis shows that the underground water stress release model outperforms both Poisson model and stress release model. Monte Carlo simulation shows that the simulated seismicity by USRM is very close to the real seismicity.
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Schaefer, Andreas; Daniell, James; Wenzel, Friedemann
2015-04-01
Earthquake forecasting and prediction has been one of the key struggles of modern geosciences for the last few decades. A large number of approaches for various time periods have been developed for different locations around the world. A categorization and review of more than 20 of new and old methods was undertaken to develop a state-of-the-art catalogue in forecasting algorithms and methodologies. The different methods have been categorised into time-independent, time-dependent and hybrid methods, from which the last group represents methods where additional data than just historical earthquake statistics have been used. It is necessary to categorize in such a way between pure statistical approaches where historical earthquake data represents the only direct data source and also between algorithms which incorporate further information e.g. spatial data of fault distributions or which incorporate physical models like static triggering to indicate future earthquakes. Furthermore, the location of application has been taken into account to identify methods which can be applied e.g. in active tectonic regions like California or in less active continental regions. In general, most of the methods cover well-known high-seismicity regions like Italy, Japan or California. Many more elements have been reviewed, including the application of established theories and methods e.g. for the determination of the completeness magnitude or whether the modified Omori law was used or not. Target temporal scales are identified as well as the publication history. All these different aspects have been reviewed and catalogued to provide an easy-to-use tool for the development of earthquake forecasting algorithms and to get an overview in the state-of-the-art.
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PRECURSORS OF EARTHQUAKES: VLF SIGNALSIONOSPHERE IONOSPHERE RELATION
Directory of Open Access Journals (Sweden)
Mustafa ULAS
2013-01-01
Full Text Available lot of people have died because of earthquakes every year. Therefore It is crucial to predict the time of the earthquakes reasonable time before it had happed. This paper presents recent information published in the literature about precursors of earthquakes. The relationships between earthquakes and ionosphere are targeted to guide new researches in order to study further to find novel prediction methods.
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Yu, Huai-Zhong; Yin, Xiang-Chu; Zhu, Qing-Yong; Yan, Yu-Ding
2006-12-01
The concept of state vector stems from statistical physics, where it is usually used to describe activity patterns of a physical field in its manner of coarsegrain. In this paper, we propose an approach by which the state vector was applied to describe quantitatively the damage evolution of the brittle heterogeneous systems, and some interesting results are presented, i.e., prior to the macro-fracture of rock specimens and occurrence of a strong earthquake, evolutions of the four relevant scalars time series derived from the state vectors changed anomalously. As retrospective studies, some prominent large earthquakes occurred in the Chinese Mainland (e.g., the M 7.4 Haicheng earthquake on February 4, 1975, and the M 7.8 Tangshan earthquake on July 28, 1976, etc) were investigated. Results show considerable promise that the time-dependent state vectors could serve as a kind of precursor to predict earthquakes.
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New streams and springs after the 2014 Mw6.0 South Napa earthquake.
Wang, Chi-Yuen; Manga, Michael
2015-07-09
Many streams and springs, which were dry or nearly dry before the 2014 Mw6.0 South Napa earthquake, started to flow after the earthquake. A United States Geological Survey stream gauge also registered a coseismic increase in discharge. Public interest was heightened by a state of extreme drought in California. Since the new flows were not contaminated by pre-existing surface water, their composition allowed unambiguous identification of their origin. Following the earthquake we repeatedly surveyed the new flows, collecting data to test hypotheses about their origin. We show that the new flows originated from groundwater in nearby mountains released by the earthquake. The estimated total amount of new water is ∼ 10(6) m(3), about 1/40 of the annual water use in the Napa-Sonoma area. Our model also makes a testable prediction of a post-seismic decrease of seismic velocity in the shallow crust of the affected region.
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Earthquake forewarning in the Cascadia region
Gomberg, Joan S.; Atwater, Brian F.; Beeler, Nicholas M.; Bodin, Paul; Davis, Earl; Frankel, Arthur; Hayes, Gavin P.; McConnell, Laura; Melbourne, Tim; Oppenheimer, David H.; Parrish, John G.; Roeloffs, Evelyn A.; Rogers, Gary D.; Sherrod, Brian; Vidale, John; Walsh, Timothy J.; Weaver, Craig S.; Whitmore, Paul M.
2015-08-10
This report, prepared for the National Earthquake Prediction Evaluation Council (NEPEC), is intended as a step toward improving communications about earthquake hazards between information providers and users who coordinate emergency-response activities in the Cascadia region of the Pacific Northwest. NEPEC charged a subcommittee of scientists with writing this report about forewarnings of increased probabilities of a damaging earthquake. We begin by clarifying some terminology; a “prediction” refers to a deterministic statement that a particular future earthquake will or will not occur. In contrast to the 0- or 100-percent likelihood of a deterministic prediction, a “forecast” describes the probability of an earthquake occurring, which may range from >0 to processes or conditions, which may include Increased rates of M>4 earthquakes on the plate interface north of the Mendocino region
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Modeling, Forecasting and Mitigating Extreme Earthquakes
Ismail-Zadeh, A.; Le Mouel, J.; Soloviev, A.
2012-12-01
Recent earthquake disasters highlighted the importance of multi- and trans-disciplinary studies of earthquake risk. A major component of earthquake disaster risk analysis is hazards research, which should cover not only a traditional assessment of ground shaking, but also studies of geodetic, paleoseismic, geomagnetic, hydrological, deep drilling and other geophysical and geological observations together with comprehensive modeling of earthquakes and forecasting extreme events. Extreme earthquakes (large magnitude and rare events) are manifestations of complex behavior of the lithosphere structured as a hierarchical system of blocks of different sizes. Understanding of physics and dynamics of the extreme events comes from observations, measurements and modeling. A quantitative approach to simulate earthquakes in models of fault dynamics will be presented. The models reproduce basic features of the observed seismicity (e.g., the frequency-magnitude relationship, clustering of earthquakes, occurrence of extreme seismic events). They provide a link between geodynamic processes and seismicity, allow studying extreme events, influence of fault network properties on seismic patterns and seismic cycles, and assist, in a broader sense, in earthquake forecast modeling. Some aspects of predictability of large earthquakes (how well can large earthquakes be predicted today?) will be also discussed along with possibilities in mitigation of earthquake disasters (e.g., on 'inverse' forensic investigations of earthquake disasters).
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The GIS and analysis of earthquake damage distribution of the 1303 Hongtong M=8 earthquake
Gao, Meng-Tan; Jin, Xue-Shen; An, Wei-Ping; Lü, Xiao-Jian
2004-07-01
The geography information system of the 1303 Hongton M=8 earthquake has been established. Using the spatial analysis function of GIS, the spatial distribution characteristics of damage and isoseismal of the earthquake are studies. By comparing with the standard earthquake intensity attenuation relationship, the abnormal damage distribution of the earthquake is found, so the relationship of the abnormal distribution with tectonics, site condition and basin are analyzed. In this paper, the influence on the ground motion generated by earthquake source and the underground structures near source also are studied. The influence on seismic zonation, anti-earthquake design, earthquake prediction and earthquake emergency responding produced by the abnormal density distribution are discussed.
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Understanding and Predicting the Process of Software Maintenance Releases
Basili, Victor; Briand, Lionel; Condon, Steven; Kim, Yong-Mi; Melo, Walcelio L.; Valett, Jon D.
1996-01-01
One of the major concerns of any maintenance organization is to understand and estimate the cost of maintenance releases of software systems. Planning the next release so as to maximize the increase in functionality and the improvement in quality are vital to successful maintenance management. The objective of this paper is to present the results of a case study in which an incremental approach was used to better understand the effort distribution of releases and build a predictive effort model for software maintenance releases. This study was conducted in the Flight Dynamics Division (FDD) of NASA Goddard Space Flight Center(GSFC). This paper presents three main results: 1) a predictive effort model developed for the FDD's software maintenance release process; 2) measurement-based lessons learned about the maintenance process in the FDD; and 3) a set of lessons learned about the establishment of a measurement-based software maintenance improvement program. In addition, this study provides insights and guidelines for obtaining similar results in other maintenance organizations.
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Thermal Radiation Anomalies Associated with Major Earthquakes
Ouzounov, Dimitar; Pulinets, Sergey; Kafatos, Menas C.; Taylor, Patrick
2017-01-01
Recent developments of remote sensing methods for Earth satellite data analysis contribute to our understanding of earthquake related thermal anomalies. It was realized that the thermal heat fluxes over areas of earthquake preparation is a result of air ionization by radon (and other gases) and consequent water vapor condensation on newly formed ions. Latent heat (LH) is released as a result of this process and leads to the formation of local thermal radiation anomalies (TRA) known as OLR (outgoing Longwave radiation, Ouzounov et al, 2007). We compare the LH energy, obtained by integrating surface latent heat flux (SLHF) over the area and time with released energies associated with these events. Extended studies of the TRA using the data from the most recent major earthquakes allowed establishing the main morphological features. It was also established that the TRA are the part of more complex chain of the short-term pre-earthquake generation, which is explained within the framework of a lithosphere-atmosphere coupling processes.
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Wang, Lifeng; Hainzl, Sebastian; Mai, Paul Martin
2015-01-01
The long-term slip on faults has to follow, on average, the plate motion, while slip deficit is accumulated over shorter time scales (e.g., between the large earthquakes). Accumulated slip deficits eventually have to be released by earthquakes and aseismic processes. In this study, we propose a new inversion approach for coseismic slip, taking interseismic slip deficit as prior information. We assume a linear correlation between coseismic slip and interseismic slip deficit, and invert for the coefficients that link the coseismic displacements to the required strain accumulation time and seismic release level of the earthquake. We apply our approach to the 2011 M9 Tohoku-Oki earthquake and the 2004 M6 Parkfield earthquake. Under the assumption that the largest slip almost fully releases the local strain (as indicated by borehole measurements, Lin et al., 2013), our results suggest that the strain accumulated along the Tohoku-Oki earthquake segment has been almost fully released during the 2011 M9 rupture. The remaining slip deficit can be attributed to the postseismic processes. Similar conclusions can be drawn for the 2004 M6 Parkfield earthquake. We also estimate the required time of strain accumulation for the 2004 M6 Parkfield earthquake to be ~25 years (confidence interval of [17, 43] years), consistent with the observed average recurrence time of ~22 years for M6 earthquakes in Parkfield. For the Tohoku-Oki earthquake, we estimate the recurrence time of~500-700 years. This new inversion approach for evaluating slip balance can be generally applied to any earthquake for which dense geodetic measurements are available.
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Wang, Lifeng
2015-11-11
The long-term slip on faults has to follow, on average, the plate motion, while slip deficit is accumulated over shorter time scales (e.g., between the large earthquakes). Accumulated slip deficits eventually have to be released by earthquakes and aseismic processes. In this study, we propose a new inversion approach for coseismic slip, taking interseismic slip deficit as prior information. We assume a linear correlation between coseismic slip and interseismic slip deficit, and invert for the coefficients that link the coseismic displacements to the required strain accumulation time and seismic release level of the earthquake. We apply our approach to the 2011 M9 Tohoku-Oki earthquake and the 2004 M6 Parkfield earthquake. Under the assumption that the largest slip almost fully releases the local strain (as indicated by borehole measurements, Lin et al., 2013), our results suggest that the strain accumulated along the Tohoku-Oki earthquake segment has been almost fully released during the 2011 M9 rupture. The remaining slip deficit can be attributed to the postseismic processes. Similar conclusions can be drawn for the 2004 M6 Parkfield earthquake. We also estimate the required time of strain accumulation for the 2004 M6 Parkfield earthquake to be ~25 years (confidence interval of [17, 43] years), consistent with the observed average recurrence time of ~22 years for M6 earthquakes in Parkfield. For the Tohoku-Oki earthquake, we estimate the recurrence time of~500-700 years. This new inversion approach for evaluating slip balance can be generally applied to any earthquake for which dense geodetic measurements are available.
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The threat of silent earthquakes
Cervelli, Peter
2004-01-01
Not all earthquakes shake the ground. The so-called silent types are forcing scientists to rethink their understanding of the way quake-prone faults behave. In rare instances, silent earthquakes that occur along the flakes of seaside volcanoes may cascade into monstrous landslides that crash into the sea and trigger towering tsunamis. Silent earthquakes that take place within fault zones created by one tectonic plate diving under another may increase the chance of ground-shaking shocks. In other locations, however, silent slip may decrease the likelihood of destructive quakes, because they release stress along faults that might otherwise seem ready to snap.
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Wang, Jian; Main, Ian G.; Musson, Roger M. W.
2017-11-01
Beijing, China's capital city, is located in a typical intraplate seismic belt, with relatively high-quality instrumental catalogue data available since 1970. The Chinese historical earthquake catalogue contains six strong historical earthquakes of Ms ≥ 6 around Beijing, the earliest in 294 AD. This poses a significant potential hazard to one of the most densely populated and economically active parts of China. In some intraplate areas, persistent clusters of events associated with historical events can occur over centuries, for example, the ongoing sequence in the New Madrid zone of the eastern US. Here we will examine the evidence for such persistent clusters around Beijing. We introduce a metric known as the `seismic density index' that quantifies the degree of clustering of seismic energy release. For a given map location, this multi-dimensional index depends on the number of events, their magnitudes, and the distances to the locations of the surrounding population of earthquakes. We apply the index to modern instrumental catalogue data between 1970 and 2014, and identify six clear candidate zones. We then compare these locations to earthquake epicentre and seismic intensity data for the six largest historical earthquakes. Each candidate zone contains one of the six historical events, and the location of peak intensity is within 5 km or so of the reported epicentre in five of these cases. In one case—the great Ms 8 earthquake of 1679—the peak is closer to the area of strongest shaking (Intensity XI or more) than the reported epicentre. The present-day event rates are similar to those predicted by the modified Omori law but there is no evidence of ongoing decay in event rates. Accordingly, the index is more likely to be picking out the location of persistent weaknesses in the lithosphere. Our results imply zones of high seismic density index could be used in principle to indicate the location of unrecorded historical of palaeoseismic events, in China and
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Herrera, C.; Cassidy, J. F.; Dosso, S. E.
2017-12-01
The ground shaking assessment allows quantifying the hazards associated with the occurrence of earthquakes. Chile and western Canada are two areas that have experienced, and are susceptible to imminent large crustal, in-slab and megathrust earthquakes that can affect the population significantly. In this context, we compare the current GMPEs used in the 2015 National Building Code of Canada and the most recent GMPEs calculated for Chile, with observed accelerations generated by four recent Chilean megathrust earthquakes (MW ≥ 7.7) that have occurred during the past decade, which is essential to quantify how well current models predict observations of major events.We collected the 3-component waveform data of more than 90 stations from the Centro Sismologico Nacional and the Universidad de Chile, and processed them by removing the trend and applying a band-pass filter. Then, for each station, we obtained the Peak Ground Acceleration (PGA), and by using a damped response spectra, we calculated the Pseudo Spectral Acceleration (PSA). Finally, we compared those observations with the most recent Chilean and Canadian GMPEs. Given the lack of geotechnical information for most of the Chilean stations, we also used a new method to obtain the VS30 by inverting the H/V ratios using a trans-dimensional Bayesian inversion, which allows us to improve the correction of observations according to soil conditions.As expected, our results show a good fit between observations and the Chilean GMPEs, but we observe that although the shape of the Canadian GMPEs is coherent with the distribution of observations, in general they under predict the observations for PGA and PSA at shorter periods for most of the considered earthquakes. An example of this can be seen in the attached figure for the case of the 2014 Iquique earthquake.These results present important implications related to the hazards associated to large earthquakes, especially for western Canada, where the probability of a
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Retrospective stress-forecasting of earthquakes
Gao, Yuan; Crampin, Stuart
2015-04-01
Observations of changes in azimuthally varying shear-wave splitting (SWS) above swarms of small earthquakes monitor stress-induced changes to the stress-aligned vertical microcracks pervading the upper crust, lower crust, and uppermost ~400km of the mantle. (The microcracks are intergranular films of hydrolysed melt in the mantle.) Earthquakes release stress, and an appropriate amount of stress for the relevant magnitude must accumulate before each event. Iceland is on an extension of the Mid-Atlantic Ridge, where two transform zones, uniquely run onshore. These onshore transform zones provide semi-continuous swarms of small earthquakes, which are the only place worldwide where SWS can be routinely monitored. Elsewhere SWS must be monitored above temporally-active occasional swarms of small earthquakes, or in infrequent SKS and other teleseismic reflections from the mantle. Observations of changes in SWS time-delays are attributed to stress-induced changes in crack aspect-ratios allowing stress-accumulation and stress-relaxation to be identified. Monitoring SWS in SW Iceland in 1988, stress-accumulation before an impending earthquake was recognised and emails were exchanged between the University of Edinburgh (EU) and the Iceland Meteorological Office (IMO). On 10th November 1988, EU emailed IMO that a M5 earthquake could occur soon on a seismically-active fault plane where seismicity was still continuing following a M5.1 earthquake six-months earlier. Three-days later, IMO emailed EU that a M5 earthquake had just occurred on the specified fault-plane. We suggest this is a successful earthquake stress-forecast, where we refer to the procedure as stress-forecasting earthquakes as opposed to predicting or forecasting to emphasise the different formalism. Lack of funds has prevented us monitoring SWS on Iceland seismograms, however, we have identified similar characteristic behaviour of SWS time-delays above swarms of small earthquakes which have enabled us to
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Refresher Course on Physics of Earthquakes -98 ...
Indian Academy of Sciences (India)
The objective of this course is to help teachers gain an understanding of the earhquake phenomenon and the physical processes involved in its genesis as well as offhe earthquake waves which propagate the energy released by the earthquake rupture outward from the source. The Course will begin with mathematical ...
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Statistical physics approach to earthquake occurrence and forecasting
Energy Technology Data Exchange (ETDEWEB)
Arcangelis, Lucilla de [Department of Industrial and Information Engineering, Second University of Naples, Aversa (CE) (Italy); Godano, Cataldo [Department of Mathematics and Physics, Second University of Naples, Caserta (Italy); Grasso, Jean Robert [ISTerre, IRD-CNRS-OSUG, University of Grenoble, Saint Martin d’Héres (France); Lippiello, Eugenio, E-mail: eugenio.lippiello@unina2.it [Department of Mathematics and Physics, Second University of Naples, Caserta (Italy)
2016-04-25
There is striking evidence that the dynamics of the Earth crust is controlled by a wide variety of mutually dependent mechanisms acting at different spatial and temporal scales. The interplay of these mechanisms produces instabilities in the stress field, leading to abrupt energy releases, i.e., earthquakes. As a consequence, the evolution towards instability before a single event is very difficult to monitor. On the other hand, collective behavior in stress transfer and relaxation within the Earth crust leads to emergent properties described by stable phenomenological laws for a population of many earthquakes in size, time and space domains. This observation has stimulated a statistical mechanics approach to earthquake occurrence, applying ideas and methods as scaling laws, universality, fractal dimension, renormalization group, to characterize the physics of earthquakes. In this review we first present a description of the phenomenological laws of earthquake occurrence which represent the frame of reference for a variety of statistical mechanical models, ranging from the spring-block to more complex fault models. Next, we discuss the problem of seismic forecasting in the general framework of stochastic processes, where seismic occurrence can be described as a branching process implementing space–time-energy correlations between earthquakes. In this context we show how correlations originate from dynamical scaling relations between time and energy, able to account for universality and provide a unifying description for the phenomenological power laws. Then we discuss how branching models can be implemented to forecast the temporal evolution of the earthquake occurrence probability and allow to discriminate among different physical mechanisms responsible for earthquake triggering. In particular, the forecasting problem will be presented in a rigorous mathematical framework, discussing the relevance of the processes acting at different temporal scales for
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Seismic methodology in determining basis earthquake for nuclear installation
International Nuclear Information System (INIS)
Ameli Zamani, Sh.
2008-01-01
Design basis earthquake ground motions for nuclear installations should be determined to assure the design purpose of reactor safety: that reactors should be built and operated to pose no undue risk to public health and safety from earthquake and other hazards. Regarding the influence of seismic hazard to a site, large numbers of earthquake ground motions can be predicted considering possible variability among the source, path, and site parameters. However, seismic safety design using all predicted ground motions is practically impossible. In the determination of design basis earthquake ground motions it is therefore important to represent the influences of the large numbers of earthquake ground motions derived from the seismic ground motion prediction methods for the surrounding seismic sources. Viewing the relations between current design basis earthquake ground motion determination and modem earthquake ground motion estimation, a development of risk-informed design basis earthquake ground motion methodology is discussed for insight into the on going modernization of the Examination Guide for Seismic Design on NPP
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Prediction of strong ground motion based on scaling law of earthquake
International Nuclear Information System (INIS)
Kamae, Katsuhiro; Irikura, Kojiro; Fukuchi, Yasunaga.
1991-01-01
In order to predict more practically strong ground motion, it is important to study how to use a semi-empirical method in case of having no appropriate observation records for actual small-events as empirical Green's functions. We propose a prediction procedure using artificially simulated small ground motions as substitute for the actual motions. First, we simulate small-event motion by means of stochastic simulation method proposed by Boore (1983) in considering pass effects such as attenuation, and broadening of waveform envelope empirically in the objective region. Finally, we attempt to predict the strong ground motion due to a future large earthquake (M 7, Δ = 13 km) using the same summation procedure as the empirical Green's function method. We obtained the results that the characteristics of the synthetic motion using M 5 motion were in good agreement with those by the empirical Green's function method. (author)
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The 2007 Mentawai earthquake sequence on the Sumatra megathrust
Konca, A.; Avouac, J.; Sladen, A.; Meltzner, A. J.; Kositsky, A. P.; Sieh, K.; Fang, P.; Li, Z.; Galetzka, J.; Genrich, J.; Chlieh, M.; Natawidjaja, D. H.; Bock, Y.; Fielding, E. J.; Helmberger, D. V.
2008-12-01
The Sumatra Megathrust has recently produced a flurry of large interplate earthquakes starting with the giant Mw 9.15, Aceh earthquake of 2004. All of these earthquakes occurred within the area monitored by the Sumatra Geodetic Array (SuGAr), which provided exceptional records of near-field co-seismic and postseismic ground displacements. The most recent of these major earthquakes, an Mw 8.4 earthquake and an Mw 7.9 earthquake twelve hours later, occurred in the Mentawai islands area where devastating historical earthquakes had happened in 1797 and 1833. The 2007 earthquake sequence provides an exceptional opportunity to understand the variability of the earthquakes along megathrusts and their relation to interseismic coupling. The InSAR, GPS and teleseismic modeling shows that 2007 earthquakes ruptured a fraction of the strongly coupled Mentawai patch of the megathrust, which is also only a fraction of the 1833 rupture area. It also released a much smaller moment than the one released in 1833, or than the deficit of moment that has accumulated since. Both earthquakes of 2007 consist of 2 sub-events which are 50 to 100 km apart from each other. On the other hand, the northernmost slip patch of 8.4 and southern slip patch of 7.9 earthquakes abut each other, but they ruptured 12 hours apart. Sunda megathrust earthquakes of recent years include a rupture of a strongly coupled patch that closely mimics a prior rupture of that patch and which is well correlated with the interseismic coupling pattern (Nias-Simeulue section), as well as a rupture sequence of a strongly coupled patch that differs substantially in the details from its most recent predecessors (Mentawai section). We conclude that (1) seismic asperities are probably persistent features which arise form heterogeneous strain build up in the interseismic period; and (2) the same portion of a megathrust can rupture in different ways depending on whether asperities break as isolated events or cooperate to produce
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Earthquake Early Warning: User Education and Designing Effective Messages
Burkett, E. R.; Sellnow, D. D.; Jones, L.; Sellnow, T. L.
2014-12-01
The U.S. Geological Survey (USGS) and partners are transitioning from test-user trials of a demonstration earthquake early warning system (ShakeAlert) to deciding and preparing how to implement the release of earthquake early warning information, alert messages, and products to the public and other stakeholders. An earthquake early warning system uses seismic station networks to rapidly gather information about an occurring earthquake and send notifications to user devices ahead of the arrival of potentially damaging ground shaking at their locations. Earthquake early warning alerts can thereby allow time for actions to protect lives and property before arrival of damaging shaking, if users are properly educated on how to use and react to such notifications. A collaboration team of risk communications researchers and earth scientists is researching the effectiveness of a chosen subset of potential earthquake early warning interface designs and messages, which could be displayed on a device such as a smartphone. Preliminary results indicate, for instance, that users prefer alerts that include 1) a map to relate their location to the earthquake and 2) instructions for what to do in response to the expected level of shaking. A number of important factors must be considered to design a message that will promote appropriate self-protective behavior. While users prefer to see a map, how much information can be processed in limited time? Are graphical representations of wavefronts helpful or confusing? The most important factor to promote a helpful response is the predicted earthquake intensity, or how strong the expected shaking will be at the user's location. Unlike Japanese users of early warning, few Californians are familiar with the earthquake intensity scale, so we are exploring how differentiating instructions between intensity levels (e.g., "Be aware" for lower shaking levels and "Drop, cover, hold on" at high levels) can be paired with self-directed supplemental
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Ohyanagi, S.; Dileonardo, C.
2013-12-01
As a natural phenomenon earthquake occurrence is difficult to predict. Statistical analysis of earthquake data was performed using candlestick chart and Bollinger Band methods. These statistical methods, commonly used in the financial world to analyze market trends were tested against earthquake data. Earthquakes above Mw 4.0 located on shore of Sanriku (37.75°N ~ 41.00°N, 143.00°E ~ 144.50°E) from February 1973 to May 2013 were selected for analysis. Two specific patterns in earthquake occurrence were recognized through the analysis. One is a spread of candlestick prior to the occurrence of events greater than Mw 6.0. A second pattern shows convergence in the Bollinger Band, which implies a positive or negative change in the trend of earthquakes. Both patterns match general models for the buildup and release of strain through the earthquake cycle, and agree with both the characteristics of the candlestick chart and Bollinger Band analysis. These results show there is a high correlation between patterns in earthquake occurrence and trend analysis by these two statistical methods. The results of this study agree with the appropriateness of the application of these financial analysis methods to the analysis of earthquake occurrence.
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Do earthquakes exhibit self-organized criticality?
International Nuclear Information System (INIS)
Yang Xiaosong; Ma Jin; Du Shuming
2004-01-01
If earthquakes are phenomena of self-organized criticality (SOC), statistical characteristics of the earthquake time series should be invariant after the sequence of events in an earthquake catalog are randomly rearranged. In this Letter we argue that earthquakes are unlikely phenomena of SOC because our analysis of the Southern California Earthquake Catalog shows that the first-return-time probability P M (T) is apparently changed after the time series is rearranged. This suggests that the SOC theory should not be used to oppose the efforts of earthquake prediction
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International Nuclear Information System (INIS)
Marza, V.; Burlacu, B V.; Pantea, A; Malita, Z.
2002-01-01
This is a reissue of a paper initially published in the European Seismological Commission Proceedings of the XXI General Assembly held on 23-27 August 1988 in Sofia, Bulgaria, p. 515-523, and released in 1989. We present here an excerpt of the original paper, taking only advantage of the modern digital graphics, removing some 'typing' mistakes or adding some explanatory late notes, in order to remember the conspicuous earthquake prediction research results done by Romanian seismology after the forecasted 1977 Vrancea major event. For the sake of understanding we distinguish between earthquake forecasting (long-term prediction, that is a time-window of years, but less than 20% of the mean return period for the involved magnitude and a lead time of years) and earthquake anticipation (medium-term prediction, i.e. a time-window of a few months and a lead time of months), stages what proved to be feasible for Vrancea seismogenic zone. Analysis and discussion of a variety of precursory seismicity patterns (p.s.p.) belonging to all temporal developmental stages of the preparatory (geo)physical process leading to the killer and damaging major subcrustal Vrancea, Romania, earthquake of August 30, 1986 (epicenter = 45.5 angle N/26.4 angle E; depth 144 km; magnitude(s) m w =7.0, M w =7.3, M L =7.0; I o =VIII 1/2 MSK) are performed and documented, clearly proving that the earthquake would not has been unexpected. The salient features of the Vrancea Seismogenic Zone (VSZ) and its tectonic setting have been presented elsewhere. The seismological data base used in this study is the earthquake master catalogue of Constantinescu and Marza, updated on the basis of the data supplied by the real-time telemetered seismographic network of Romania, centered on VSZ. The contents of the paper is as follows: 1. Introduction; 2. The Vrancea 1986 Major (m w =7.0) Subcrustal Earthquake Related Precursors; 2.1. Regularity Patterns; 2.2. Preseismic Quiescence; 2.3. Hypocentral migration
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Safety and survival in an earthquake
,
1969-01-01
Many earth scientists in this country and abroad are focusing their studies on the search for means of predicting impending earthquakes, but, as yet, an accurate prediction of the time and place of such an event cannot be made. From past experience, however, one can assume that earthquakes will continue to harass mankind and that they will occur most frequently in the areas where they have been relatively common in the past. In the United States, earthquakes can be expected to occur most frequently in the western states, particularly in Alaska, California, Washington, Oregon, Nevada, Utah, and Montana. The danger, however, is not confined to any one part of the country; major earthquakes have occurred at widely scattered locations.
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International Nuclear Information System (INIS)
2002-01-01
This report describes the simplified models for predicting the response of high-damping natural rubber bearings (HDNRB) to earthquake ground motions and benchmark problems for assessing the accuracy of finite element analyses in designing base-isolators. (author)
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How fault geometry controls earthquake magnitude
Bletery, Q.; Thomas, A.; Karlstrom, L.; Rempel, A. W.; Sladen, A.; De Barros, L.
2016-12-01
Recent large megathrust earthquakes, such as the Mw9.3 Sumatra-Andaman earthquake in 2004 and the Mw9.0 Tohoku-Oki earthquake in 2011, astonished the scientific community. The first event occurred in a relatively low-convergence-rate subduction zone where events of its size were unexpected. The second event involved 60 m of shallow slip in a region thought to be aseismicaly creeping and hence incapable of hosting very large magnitude earthquakes. These earthquakes highlight gaps in our understanding of mega-earthquake rupture processes and the factors controlling their global distribution. Here we show that gradients in dip angle exert a primary control on mega-earthquake occurrence. We calculate the curvature along the major subduction zones of the world and show that past mega-earthquakes occurred on flat (low-curvature) interfaces. A simplified analytic model demonstrates that shear strength heterogeneity increases with curvature. Stress loading on flat megathrusts is more homogeneous and hence more likely to be released simultaneously over large areas than on highly-curved faults. Therefore, the absence of asperities on large faults might counter-intuitively be a source of higher hazard.
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A Decade of Giant Earthquakes - What does it mean?
Energy Technology Data Exchange (ETDEWEB)
Wallace, Terry C. Jr. [Los Alamos National Laboratory
2012-07-16
On December 26, 2004 the largest earthquake since 1964 occurred near Ache, Indonesia. The magnitude 9.2 earthquake and subsequent tsunami killed a quarter of million people; it also marked the being of a period of extraordinary seismicity. Since the Ache earthquake there have been 16 magnitude 8 earthquakes globally, including 2 this last April. For the 100 years previous to 2004 there was an average of 1 magnitude 8 earthquake every 2.2 years; since 2004 there has been 2 per year. Since magnitude 8 earthquakes dominate global seismic energy release, this period of seismicity has seismologist rethinking what they understand about plate tectonics and the connectivity between giant earthquakes. This talk will explore this remarkable period of time and its possible implications.
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Seismic damage to structures in the M s6.5 Ludian earthquake
Chen, Hao; Xie, Quancai; Dai, Boyang; Zhang, Haoyu; Chen, Hongfu
2016-03-01
On 3 August 2014, the Ludian earthquake struck northwest Yunnan Province with a surface wave magnitude of 6.5. This moderate earthquake unexpectedly caused high fatalities and great economic loss. Four strong motion stations were located in the areas with intensity V, VI, VII and IX, near the epicentre. The characteristics of the ground motion are discussed herein, including 1) ground motion was strong at a period of less than 1.4 s, which covered the natural vibration period of a large number of structures; and 2) the release energy was concentrated geographically. Based on materials collected during emergency building inspections, the damage patterns of adobe, masonry, timber frame and reinforced concrete (RC) frame structures in areas with different intensities are summarised. Earthquake damage matrices of local buildings are also given for fragility evaluation and earthquake damage prediction. It is found that the collapse ratios of RC frame and confined masonry structures based on the new design code are significantly lower than non-seismic buildings. However, the RC frame structures still failed to achieve the `strong column, weak beam' design target. Traditional timber frame structures with a light infill wall showed good aseismic performance.
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Gas and Dust Phenomena of Mega-earthquakes and the Cause
Yue, Z.
2013-12-01
A mega-earthquake suddenly releases a large to extremely large amount of kinetic energy within a few tens to two hundreds seconds and over ten to hundreds kilometer distances in the Earth's crust and on ground surface. It also generates seismic waves that can be received globally and co-seismic ground damages such co-seismic ruptures and landslides. However, such vast, dramatic and devastating kinetic actions in the Earth's crustal rocks and on the ground soils cannot be known or predicted by people at few weeks, days, hours, or minutes before they are happening. Although seismologists can develop and use seismometers to report the locations and magnitudes of earthquakes within minutes of their occurrence, they cannot predict earthquakes at present. Therefore, damage earthquakes have caused and would continue to cause huge disasters, fatalities and injuries to our human beings. This problem may indicate that it is necessary to re-examine the cause of mega-earthquakes in addition to the conventional cause of active fault elastic rebounding. In the last ten years, many mega-earthquakes occurred in China and around the Pacific Ocean and caused many casualties to human beings and devastating disasters to environments. The author will give a brief review on the impacts of the mega-earthquakes happened in recent years. He will then present many gas and dust related phenomena associated with the sudden occurrences of these mega earthquakes. They include the 2001 Kunlunshan Earthquake M8.1, 2008 Wenchuan Earthquake M8.0 and the 2010 Yushu Earthquake M7.1 in China, the 2010 Haiti Earthquake M7.0, the 2010 Mexicali Earthquake M7.2, the 2010 Chile Earthquake M8.8, the 2011 Christchurch earthquake M6.3 and the 2011 Japan Earthquake M9.0 around the Pacific Ocean. He will discuss the cause of these gas and dust related phenomena. He will use these phenomena and their common cause to show that the earthquakes were caused the rapid migration and expansion of highly compressed and
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VAN method of short-term earthquake prediction shows promise
Uyeda, Seiya
Although optimism prevailed in the 1970s, the present consensus on earthquake prediction appears to be quite pessimistic. However, short-term prediction based on geoelectric potential monitoring has stood the test of time in Greece for more than a decade [VarotsosandKulhanek, 1993] Lighthill, 1996]. The method used is called the VAN method.The geoelectric potential changes constantly due to causes such as magnetotelluric effects, lightning, rainfall, leakage from manmade sources, and electrochemical instabilities of electrodes. All of this noise must be eliminated before preseismic signals are identified, if they exist at all. The VAN group apparently accomplished this task for the first time. They installed multiple short (100-200m) dipoles with different lengths in both north-south and east-west directions and long (1-10 km) dipoles in appropriate orientations at their stations (one of their mega-stations, Ioannina, for example, now has 137 dipoles in operation) and found that practically all of the noise could be eliminated by applying a set of criteria to the data.
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Fault geometry and earthquake mechanics
Directory of Open Access Journals (Sweden)
D. J. Andrews
1994-06-01
Full Text Available Earthquake mechanics may be determined by the geometry of a fault system. Slip on a fractal branching fault surface can explain: 1 regeneration of stress irregularities in an earthquake; 2 the concentration of stress drop in an earthquake into asperities; 3 starting and stopping of earthquake slip at fault junctions, and 4 self-similar scaling of earthquakes. Slip at fault junctions provides a natural realization of barrier and asperity models without appealing to variations of fault strength. Fault systems are observed to have a branching fractal structure, and slip may occur at many fault junctions in an earthquake. Consider the mechanics of slip at one fault junction. In order to avoid a stress singularity of order 1/r, an intersection of faults must be a triple junction and the Burgers vectors on the three fault segments at the junction must sum to zero. In other words, to lowest order the deformation consists of rigid block displacement, which ensures that the local stress due to the dislocations is zero. The elastic dislocation solution, however, ignores the fact that the configuration of the blocks changes at the scale of the displacement. A volume change occurs at the junction; either a void opens or intense local deformation is required to avoid material overlap. The volume change is proportional to the product of the slip increment and the total slip since the formation of the junction. Energy absorbed at the junction, equal to confining pressure times the volume change, is not large enongh to prevent slip at a new junction. The ratio of energy absorbed at a new junction to elastic energy released in an earthquake is no larger than P/µ where P is confining pressure and µ is the shear modulus. At a depth of 10 km this dimensionless ratio has th value P/µ= 0.01. As slip accumulates at a fault junction in a number of earthquakes, the fault segments are displaced such that they no longer meet at a single point. For this reason the
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Earthquake magnitude estimation using the τ c and P d method for earthquake early warning systems
Jin, Xing; Zhang, Hongcai; Li, Jun; Wei, Yongxiang; Ma, Qiang
2013-10-01
Earthquake early warning (EEW) systems are one of the most effective ways to reduce earthquake disaster. Earthquake magnitude estimation is one of the most important and also the most difficult parts of the entire EEW system. In this paper, based on 142 earthquake events and 253 seismic records that were recorded by the KiK-net in Japan, and aftershocks of the large Wenchuan earthquake in Sichuan, we obtained earthquake magnitude estimation relationships using the τ c and P d methods. The standard variances of magnitude calculation of these two formulas are ±0.65 and ±0.56, respectively. The P d value can also be used to estimate the peak ground motion of velocity, then warning information can be released to the public rapidly, according to the estimation results. In order to insure the stability and reliability of magnitude estimation results, we propose a compatibility test according to the natures of these two parameters. The reliability of the early warning information is significantly improved though this test.
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Ionospheric Anomaly before Kyushu|Japan Earthquake
Directory of Open Access Journals (Sweden)
YANG Li
2017-05-01
Full Text Available GIM data released by IGS is used in the article and a new method of combining the Sliding Time Window Method and the Ionospheric TEC correlation analysis method of adjacent grid points is proposed to study the relationship between pre-earthquake ionospheric anomalies and earthquake. By analyzing the abnormal change of TEC in the 5 grid points around the seismic region, the abnormal change of ionospheric TEC is found before the earthquake and the correlation between the TEC sequences of lattice points is significantly affected by earthquake. Based on the analysis of the spatial distribution of TEC anomaly, anomalies of 6 h, 12 h and 6 h were found near the epicenter three days before the earthquake. Finally, ionospheric tomographic technology is used to do tomographic inversion on electron density. And the distribution of the electron density in the ionospheric anomaly is further analyzed.
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Statistical validation of earthquake related observations
Kossobokov, V. G.
2011-12-01
The confirmed fractal nature of earthquakes and their distribution in space and time implies that many traditional estimations of seismic hazard (from term-less to short-term ones) are usually based on erroneous assumptions of easy tractable or, conversely, delicately-designed models. The widespread practice of deceptive modeling considered as a "reasonable proxy" of the natural seismic process leads to seismic hazard assessment of unknown quality, which errors propagate non-linearly into inflicted estimates of risk and, eventually, into unexpected societal losses of unacceptable level. The studies aimed at forecast/prediction of earthquakes must include validation in the retro- (at least) and, eventually, in prospective tests. In the absence of such control a suggested "precursor/signal" remains a "candidate", which link to target seismic event is a model assumption. Predicting in advance is the only decisive test of forecast/predictions and, therefore, the score-card of any "established precursor/signal" represented by the empirical probabilities of alarms and failures-to-predict achieved in prospective testing must prove statistical significance rejecting the null-hypothesis of random coincidental occurrence in advance target earthquakes. We reiterate suggesting so-called "Seismic Roulette" null-hypothesis as the most adequate undisturbed random alternative accounting for the empirical spatial distribution of earthquakes: (i) Consider a roulette wheel with as many sectors as the number of earthquake locations from a sample catalog representing seismic locus, a sector per each location and (ii) make your bet according to prediction (i.e., determine, which locations are inside area of alarm, and put one chip in each of the corresponding sectors); (iii) Nature turns the wheel; (iv) accumulate statistics of wins and losses along with the number of chips spent. If a precursor in charge of prediction exposes an imperfection of Seismic Roulette then, having in mind
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The 1985 central chile earthquake: a repeat of previous great earthquakes in the region?
Comte, D; Eisenberg, A; Lorca, E; Pardo, M; Ponce, L; Saragoni, R; Singh, S K; Suárez, G
1986-07-25
A great earthquake (surface-wave magnitude, 7.8) occurred along the coast of central Chile on 3 March 1985, causing heavy damage to coastal towns. Intense foreshock activity near the epicenter of the main shock occurred for 11 days before the earthquake. The aftershocks of the 1985 earthquake define a rupture area of 170 by 110 square kilometers. The earthquake was forecast on the basis of the nearly constant repeat time (83 +/- 9 years) of great earthquakes in this region. An analysis of previous earthquakes suggests that the rupture lengths of great shocks in the region vary by a factor of about 3. The nearly constant repeat time and variable rupture lengths cannot be reconciled with time- or slip-predictable models of earthquake recurrence. The great earthquakes in the region seem to involve a variable rupture mode and yet, for unknown reasons, remain periodic. Historical data suggest that the region south of the 1985 rupture zone should now be considered a gap of high seismic potential that may rupture in a great earthquake in the next few tens of years.
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The use of radon as an earthquake precursor
International Nuclear Information System (INIS)
Ramola, R.C.; Singh, M.; Sandhu, A.S.; Singh, S.; Virk, H.S.
1990-01-01
Radon monitoring for earthquake prediction is part of an integral approach since the discovery of coherent and time anomalous radon concentrations prior to, during and after the 1966 Tashkent earthquake. In this paper some studies of groundwater and soil gas radon content in relation to earthquake activities are reviewed. Laboratory experiments and the development of groundwater and soil gas radon monitoring systems are described. In addition, radon monitoring studies conducted at the Guru Nanak Dev University Campus since 1986 are presented in detail. During these studies some anomalous changes in radon concentration were recorded before earthquakes occurred in the region. The anomalous radon increases are independent of meteorological conditions and appear to be caused by strain changes, which precede the earthquake. Anomalous changes in radon concentration before an earthquake suggest that radon monitoring can serve as an additional technique in the earthquake prediction programme in India. (author)
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International Nuclear Information System (INIS)
Romashkova, L.L.; Kossobokov, V.G.; Peresan, A.; Panza, G.F.
2001-12-01
A series of experiments, based on the intermediate-term earthquake prediction algorithm M8, has been performed for the retrospective simulation of forward predictions in the Italian territory, with the aim to design an experimental routine for real-time predictions. These experiments evidenced two main difficulties for the application of M8 in Italy. The first one is due to the fact that regional catalogues are usually limited in space. The second one concerns certain arbitrariness and instability, with respect to the positioning of the circles of investigation. Here we design a new scheme for the application of the algorithm M8, which is less subjective and less sensitive to the position of the circles of investigation. To perform this test, we consider a recent revision of the Italian catalogue, named UCI2001, composed by CCI1996, NEIC and ALPOR data for the period 1900-1985, and updated with the NEIC reduces the spatial heterogeneity of the data at the boundaries of Italy. The new variant of the M8 algorithm application reduces the number of spurious alarms and increases the reliability of predictions. As a result, three out of four earthquakes with magnitude M max larger than 6.0 are predicted in the retrospective simulation of the forward prediction, during the period 1972-2001, with a space-time volume of alarms comparable to that obtained with the non-stabilized variant of the M8 algorithm in Italy. (author)
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The USGS plan for short-term prediction of the anticipated Parkfield earthquake
Bakun, W.H.
1988-01-01
Aside from the goal of better understanding the Parkfield earthquake cycle, it is the intention of the U.S Geological Survey to attempt to issue a warning shortly before the anticipated earthquake. Although short-term earthquake warnings are not yet generally feasible, the wealth of information available for the previous significant Parkfield earthquakes suggests that if the next earthquake follows the pattern of "characteristic" Parkfield shocks, such a warning might be possible. Focusing on earthquake precursors reported for the previous "characteristic" shocks, particulary the 1934 and 1966 events, the USGS developed a plan* in late 1985 on which to base earthquake warnings for Parkfield and has assisted State, county, and local officials in the Parkfield area to prepare a coordinated, reasonable response to a warning, should one be issued.
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Thermal infrared anomalies of several strong earthquakes.
Wei, Congxin; Zhang, Yuansheng; Guo, Xiao; Hui, Shaoxing; Qin, Manzhong; Zhang, Ying
2013-01-01
In the history of earthquake thermal infrared research, it is undeniable that before and after strong earthquakes there are significant thermal infrared anomalies which have been interpreted as preseismic precursor in earthquake prediction and forecasting. In this paper, we studied the characteristics of thermal radiation observed before and after the 8 great earthquakes with magnitude up to Ms7.0 by using the satellite infrared remote sensing information. We used new types of data and method to extract the useful anomaly information. Based on the analyses of 8 earthquakes, we got the results as follows. (1) There are significant thermal radiation anomalies before and after earthquakes for all cases. The overall performance of anomalies includes two main stages: expanding first and narrowing later. We easily extracted and identified such seismic anomalies by method of "time-frequency relative power spectrum." (2) There exist evident and different characteristic periods and magnitudes of thermal abnormal radiation for each case. (3) Thermal radiation anomalies are closely related to the geological structure. (4) Thermal radiation has obvious characteristics in abnormal duration, range, and morphology. In summary, we should be sure that earthquake thermal infrared anomalies as useful earthquake precursor can be used in earthquake prediction and forecasting.
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Two critical tests for the Critical Point earthquake
Tzanis, A.; Vallianatos, F.
2003-04-01
It has been credibly argued that the earthquake generation process is a critical phenomenon culminating with a large event that corresponds to some critical point. In this view, a great earthquake represents the end of a cycle on its associated fault network and the beginning of a new one. The dynamic organization of the fault network evolves as the cycle progresses and a great earthquake becomes more probable, thereby rendering possible the prediction of the cycle’s end by monitoring the approach of the fault network toward a critical state. This process may be described by a power-law time-to-failure scaling of the cumulative seismic release rate. Observational evidence has confirmed the power-law scaling in many cases and has empirically determined that the critical exponent in the power law is typically of the order n=0.3. There are also two theoretical predictions for the value of the critical exponent. Ben-Zion and Lyakhovsky (Pure appl. geophys., 159, 2385-2412, 2002) give n=1/3. Rundle et al. (Pure appl. geophys., 157, 2165-2182, 2000) show that the power-law activation associated with a spinodal instability is essentially identical to the power-law acceleration of Benioff strain observed prior to earthquakes; in this case n=0.25. More recently, the CP model has gained support from the development of more dependable models of regional seismicity with realistic fault geometry that show accelerating seismicity before large events. Essentially, these models involve stress transfer to the fault network during the cycle such, that the region of accelerating seismicity will scale with the size of the culminating event, as for instance in Bowman and King (Geophys. Res. Let., 38, 4039-4042, 2001). It is thus possible to understand the observed characteristics of distributed accelerating seismicity in terms of a simple process of increasing tectonic stress in a region already subjected to stress inhomogeneities at all scale lengths. Then, the region of
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Bose, Maren; Graves, Robert; Gill, David; Callaghan, Scott; Maechling, Phillip J.
2014-01-01
Real-time applications such as earthquake early warning (EEW) typically use empirical ground-motion prediction equations (GMPEs) along with event magnitude and source-to-site distances to estimate expected shaking levels. In this simplified approach, effects due to finite-fault geometry, directivity and site and basin response are often generalized, which may lead to a significant under- or overestimation of shaking from large earthquakes (M > 6.5) in some locations. For enhanced site-specific ground-motion predictions considering 3-D wave-propagation effects, we develop support vector regression (SVR) models from the SCEC CyberShake low-frequency (415 000 finite-fault rupture scenarios (6.5 ≤ M ≤ 8.5) for southern California defined in UCERF 2.0. We use CyberShake to demonstrate the application of synthetic waveform data to EEW as a ‘proof of concept’, being aware that these simulations are not yet fully validated and might not appropriately sample the range of rupture uncertainty. Our regression models predict the maximum and the temporal evolution of instrumental intensity (MMI) at 71 selected test sites using only the hypocentre, magnitude and rupture ratio, which characterizes uni- and bilateral rupture propagation. Our regression approach is completely data-driven (where here the CyberShake simulations are considered data) and does not enforce pre-defined functional forms or dependencies among input parameters. The models were established from a subset (∼20 per cent) of CyberShake simulations, but can explain MMI values of all >400 k rupture scenarios with a standard deviation of about 0.4 intensity units. We apply our models to determine threshold magnitudes (and warning times) for various active faults in southern California that earthquakes need to exceed to cause at least ‘moderate’, ‘strong’ or ‘very strong’ shaking in the Los Angeles (LA) basin. These thresholds are used to construct a simple and robust EEW algorithm: to
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Flicker-noise Spectroscopy In Earthquake Prediction Research
Desherevsky, A. V.; Lukk, A. A.; Sidorin, A. Y.; Timashev, S. F.
It has been found out that a two-component model including a seasonal and a flicker- noise components occurs to be a more adequate model of statistical structure of time series of long-term geophysical observations' data. Unlike a white noise which sig- nifies absence of any relation between the system's current dynamics and past events in it, presence of flicker-noise indicates that such a relation in the system does ex- ist. Flicker-noise pertains a property of scale invariance. It seems natural to relate self-similarity of statistical properties of geophysical parameters' variations on dif- ferent scales to self-similar (fractal) properties of geophysical medium. At the same time self-similar time variations of geophysical parameters may indicate to presence of deterministic chaos in geophysical system's evolution. An important element of a proposed approach is application of stochastic models of preparation of each concrete large seismic event. Instead of regular, for example bay-form precursor variations, occurrence of precursors of another kind associated in particular with variation in parameter fluctuations should be expected. To solve a problem of large earthquakes prediction we use Flicker-Noise Spectroscopy (FNS) as a basis of a new approach proposed by us. The basis of the FNS methodology is a postulate about the impor- tant information significance of sequences of various dynamic irregularities (bursts or spikes, jumps with different characteristic values, discontinuities of derivatives) of the measured temporal, spatial and energetic variables on each level of hierarchical orga- nization of studied systems. A proposed new method using integral values of analyzed signals - power spectra and different moments ("structural functions") of a different order as information relations, has demonstrated principally new opportunities in a search of large earthquake precursors already at a preliminary stage of some data analysis. This research was supported by
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Use of Kazakh nuclear explosions for testing dilatancy diffusion model of earthquake prediction
International Nuclear Information System (INIS)
Srivastava, H.N.
1979-01-01
P wave travel time anomalies from Kazakh explosions during the years 1965-1972 were studied with reference to Jeffreys Bullen (1952) and Herrin Travel time tables (1968) and discussed using F ratio test at seven stations in Himachal Pradesh. For these events, the temporal and spatial variations of travel time residuals were examined from the point of view of long term changes in velocity known to precede earthquakes and local geology. The results show perference for Herrin Travel time tables at these epicentral distances from Kazakh explosions. F ratio test indicated that variation between sample means of different stations in the network showed more variation than can be attributed to the sampling error. Although the spatial variation of mean residuals (1965-1972) could generally be explained on the basis of the local geology, the temporal variations of such residuals from Kazakh explosions offer limited application in the testing of dilatancy model of earthquake prediction. (auth.)
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Quantitative prediction of strong motion for a potential earthquake fault
Directory of Open Access Journals (Sweden)
Shamita Das
2010-02-01
Full Text Available This paper describes a new method for calculating strong motion records for a given seismic region on the basis of the laws of physics using information on the tectonics and physical properties of the earthquake fault. Our method is based on a earthquake model, called a «barrier model», which is characterized by five source parameters: fault length, width, maximum slip, rupture velocity, and barrier interval. The first three parameters may be constrained from plate tectonics, and the fourth parameter is roughly a constant. The most important parameter controlling the earthquake strong motion is the last parameter, «barrier interval». There are three methods to estimate the barrier interval for a given seismic region: 1 surface measurement of slip across fault breaks, 2 model fitting with observed near and far-field seismograms, and 3 scaling law data for small earthquakes in the region. The barrier intervals were estimated for a dozen earthquakes and four seismic regions by the above three methods. Our preliminary results for California suggest that the barrier interval may be determined if the maximum slip is given. The relation between the barrier interval and maximum slip varies from one seismic region to another. For example, the interval appears to be unusually long for Kilauea, Hawaii, which may explain why only scattered evidence of strong ground shaking was observed in the epicentral area of the Island of Hawaii earthquake of November 29, 1975. The stress drop associated with an individual fault segment estimated from the barrier interval and maximum slip lies between 100 and 1000 bars. These values are about one order of magnitude greater than those estimated earlier by the use of crack models without barriers. Thus, the barrier model can resolve, at least partially, the well known discrepancy between the stress-drops measured in the laboratory and those estimated for earthquakes.
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Magnitude Estimation for Large Earthquakes from Borehole Recordings
Eshaghi, A.; Tiampo, K. F.; Ghofrani, H.; Atkinson, G.
2012-12-01
We present a simple and fast method for magnitude determination technique for earthquake and tsunami early warning systems based on strong ground motion prediction equations (GMPEs) in Japan. This method incorporates borehole strong motion records provided by the Kiban Kyoshin network (KiK-net) stations. We analyzed strong ground motion data from large magnitude earthquakes (5.0 ≤ M ≤ 8.1) with focal depths < 50 km and epicentral distances of up to 400 km from 1996 to 2010. Using both peak ground acceleration (PGA) and peak ground velocity (PGV) we derived GMPEs in Japan. These GMPEs are used as the basis for regional magnitude determination. Predicted magnitudes from PGA values (Mpga) and predicted magnitudes from PGV values (Mpgv) were defined. Mpga and Mpgv strongly correlate with the moment magnitude of the event, provided sufficient records for each event are available. The results show that Mpgv has a smaller standard deviation in comparison to Mpga when compared with the estimated magnitudes and provides a more accurate early assessment of earthquake magnitude. We test this new method to estimate the magnitude of the 2011 Tohoku earthquake and we present the results of this estimation. PGA and PGV from borehole recordings allow us to estimate the magnitude of this event 156 s and 105 s after the earthquake onset, respectively. We demonstrate that the incorporation of borehole strong ground-motion records immediately available after the occurrence of large earthquakes significantly increases the accuracy of earthquake magnitude estimation and the associated improvement in earthquake and tsunami early warning systems performance. Moment magnitude versus predicted magnitude (Mpga and Mpgv).
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Retrospective Evaluation of the Long-Term CSEP-Italy Earthquake Forecasts
Werner, M. J.; Zechar, J. D.; Marzocchi, W.; Wiemer, S.
2010-12-01
On 1 August 2009, the global Collaboratory for the Study of Earthquake Predictability (CSEP) launched a prospective and comparative earthquake predictability experiment in Italy. The goal of the CSEP-Italy experiment is to test earthquake occurrence hypotheses that have been formalized as probabilistic earthquake forecasts over temporal scales that range from days to years. In the first round of forecast submissions, members of the CSEP-Italy Working Group presented eighteen five-year and ten-year earthquake forecasts to the European CSEP Testing Center at ETH Zurich. We considered the twelve time-independent earthquake forecasts among this set and evaluated them with respect to past seismicity data from two Italian earthquake catalogs. Here, we present the results of tests that measure the consistency of the forecasts with the past observations. Besides being an evaluation of the submitted time-independent forecasts, this exercise provided insight into a number of important issues in predictability experiments with regard to the specification of the forecasts, the performance of the tests, and the trade-off between the robustness of results and experiment duration.
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Mechanistic prediction of iodine and cesium release from LWR fuel
International Nuclear Information System (INIS)
Rest, J.
1983-12-01
A theoretical model (FASTGRASS) has been used for predicting the behavior of fission gas and volatile fission products (VFPs) in UO 2 -base fuels during steady-state and transient conditions. This model represents an attempt to develop an efficient predictive capability for the full range of possible reactor operating conditions. Fission products released from the fuel are assumed to reach the fuel surface by successively diffusing (via atomic and gas-bubble mobility) from the grains to grain faces and then to the grain edges, where the fission products are released through a network of interconnected tunnels of fission-gas-induced and fabricated porosity
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Yokoi, S.; Tsuruoka, H.; Nanjo, K.; Hirata, N.
2012-12-01
Collaboratory for the Study of Earthquake Predictability (CSEP) is a global project on earthquake predictability research. The final goal of this project is to search for the intrinsic predictability of the earthquake rupture process through forecast testing experiments. The Earthquake Research Institute, the University of Tokyo joined CSEP and started the Japanese testing center called as CSEP-Japan. This testing center provides an open access to researchers contributing earthquake forecast models applied to Japan. Now more than 100 earthquake forecast models were submitted on the prospective experiment. The models are separated into 4 testing classes (1 day, 3 months, 1 year and 3 years) and 3 testing regions covering an area of Japan including sea area, Japanese mainland and Kanto district. We evaluate the performance of the models in the official suite of tests defined by CSEP. The total number of experiments was implemented for approximately 300 rounds. These results provide new knowledge concerning statistical forecasting models. We started a study for constructing a 3-dimensional earthquake forecasting model for Kanto district in Japan based on CSEP experiments under the Special Project for Reducing Vulnerability for Urban Mega Earthquake Disasters. Because seismicity of the area ranges from shallower part to a depth of 80 km due to subducting Philippine Sea plate and Pacific plate, we need to study effect of depth distribution. We will develop models for forecasting based on the results of 2-D modeling. We defined the 3D - forecasting area in the Kanto region with test classes of 1 day, 3 months, 1 year and 3 years, and magnitudes from 4.0 to 9.0 as in CSEP-Japan. In the first step of the study, we will install RI10K model (Nanjo, 2011) and the HISTETAS models (Ogata, 2011) to know if those models have good performance as in the 3 months 2-D CSEP-Japan experiments in the Kanto region before the 2011 Tohoku event (Yokoi et al., in preparation). We use CSEP
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Prediction of maximum earthquake intensities for the San Francisco Bay region
Borcherdt, Roger D.; Gibbs, James F.
1975-01-01
The intensity data for the California earthquake of April 18, 1906, are strongly dependent on distance from the zone of surface faulting and the geological character of the ground. Considering only those sites (approximately one square city block in size) for which there is good evidence for the degree of ascribed intensity, the empirical relation derived between 1906 intensities and distance perpendicular to the fault for 917 sites underlain by rocks of the Franciscan Formation is: Intensity = 2.69 - 1.90 log (Distance) (km). For sites on other geologic units intensity increments, derived with respect to this empirical relation, correlate strongly with the Average Horizontal Spectral Amplifications (AHSA) determined from 99 three-component recordings of ground motion generated by nuclear explosions in Nevada. The resulting empirical relation is: Intensity Increment = 0.27 +2.70 log (AHSA), and average intensity increments for the various geologic units are -0.29 for granite, 0.19 for Franciscan Formation, 0.64 for the Great Valley Sequence, 0.82 for Santa Clara Formation, 1.34 for alluvium, 2.43 for bay mud. The maximum intensity map predicted from these empirical relations delineates areas in the San Francisco Bay region of potentially high intensity from future earthquakes on either the San Andreas fault or the Hazard fault.
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Prediction of maximum earthquake intensities for the San Francisco Bay region
Energy Technology Data Exchange (ETDEWEB)
Borcherdt, R.D.; Gibbs, J.F.
1975-01-01
The intensity data for the California earthquake of Apr 18, 1906, are strongly dependent on distance from the zone of surface faulting and the geological character of the ground. Considering only those sites (approximately one square city block in size) for which there is good evidence for the degree of ascribed intensity, the empirical relation derived between 1906 intensities and distance perpendicular to the fault for 917 sites underlain by rocks of the Franciscan formation is intensity = 2.69 - 1.90 log (distance) (km). For sites on other geologic units, intensity increments, derived with respect to this empirical relation, correlate strongly with the average horizontal spectral amplifications (AHSA) determined from 99 three-component recordings of ground motion generated by nuclear explosions in Nevada. The resulting empirical relation is intensity increment = 0.27 + 2.70 log (AHSA), and average intensity increments for the various geologic units are -0.29 for granite, 0.19 for Franciscan formation, 0.64 for the Great Valley sequence, 0.82 for Santa Clara formation, 1.34 for alluvium, and 2.43 for bay mud. The maximum intensity map predicted from these empirical relations delineates areas in the San Francisco Bay region of potentially high intensity from future earthquakes on either the San Andreas fault or the Hayward fault.
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Holzer, T. L.; Noce, T. E.; Bennett, M. J.
2008-12-01
Probabilities of surface manifestations of liquefaction due to a repeat of the 1868 (M6.7-7.0) earthquake on the southern segment of the Hayward Fault were calculated for two areas along the margin of San Francisco Bay, California: greater Oakland and the northern Santa Clara Valley. Liquefaction is predicted to be more common in the greater Oakland area than in the northern Santa Clara Valley owing to the presence of 57 km2 of susceptible sandy artificial fill. Most of the fills were placed into San Francisco Bay during the first half of the 20th century to build military bases, port facilities, and shoreline communities like Alameda and Bay Farm Island. Probabilities of liquefaction in the area underlain by this sandy artificial fill range from 0.2 to ~0.5 for a M7.0 earthquake, and decrease to 0.1 to ~0.4 for a M6.7 earthquake. In the greater Oakland area, liquefaction probabilities generally are less than 0.05 for Holocene alluvial fan deposits, which underlie most of the remaining flat-lying urban area. In the northern Santa Clara Valley for a M7.0 earthquake on the Hayward Fault and an assumed water-table depth of 1.5 m (the historically shallowest water level), liquefaction probabilities range from 0.1 to 0.2 along Coyote and Guadalupe Creeks, but are less than 0.05 elsewhere. For a M6.7 earthquake, probabilities are greater than 0.1 along Coyote Creek but decrease along Guadalupe Creek to less than 0.1. Areas with high probabilities in the Santa Clara Valley are underlain by latest Holocene alluvial fan levee deposits where liquefaction and lateral spreading occurred during large earthquakes in 1868 and 1906. The liquefaction scenario maps were created with ArcGIS ModelBuilder. Peak ground accelerations first were computed with the new Boore and Atkinson NGA attenuation relation (2008, Earthquake Spectra, 24:1, p. 99-138), using VS30 to account for local site response. Spatial liquefaction probabilities were then estimated using the predicted ground motions
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Earthquake focal mechanism forecasting in Italy for PSHA purposes
Roselli, Pamela; Marzocchi, Warner; Mariucci, Maria Teresa; Montone, Paola
2018-01-01
In this paper, we put forward a procedure that aims to forecast focal mechanism of future earthquakes. One of the primary uses of such forecasts is in probabilistic seismic hazard analysis (PSHA); in fact, aiming at reducing the epistemic uncertainty, most of the newer ground motion prediction equations consider, besides the seismicity rates, the forecast of the focal mechanism of the next large earthquakes as input data. The data set used to this purpose is relative to focal mechanisms taken from the latest stress map release for Italy containing 392 well-constrained solutions of events, from 1908 to 2015, with Mw ≥ 4 and depths from 0 down to 40 km. The data set considers polarity focal mechanism solutions until to 1975 (23 events), whereas for 1976-2015, it takes into account only the Centroid Moment Tensor (CMT)-like earthquake focal solutions for data homogeneity. The forecasting model is rooted in the Total Weighted Moment Tensor concept that weighs information of past focal mechanisms evenly distributed in space, according to their distance from the spatial cells and magnitude. Specifically, for each cell of a regular 0.1° × 0.1° spatial grid, the model estimates the probability to observe a normal, reverse, or strike-slip fault plane solution for the next large earthquakes, the expected moment tensor and the related maximum horizontal stress orientation. These results will be available for the new PSHA model for Italy under development. Finally, to evaluate the reliability of the forecasts, we test them with an independent data set that consists of some of the strongest earthquakes with Mw ≥ 3.9 occurred during 2016 in different Italian tectonic provinces.
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Real-time earthquake data feasible
Bush, Susan
Scientists agree that early warning devices and monitoring of both Hurricane Hugo and the Mt. Pinatubo volcanic eruption saved thousands of lives. What would it take to develop this sort of early warning and monitoring system for earthquake activity?Not all that much, claims a panel assigned to study the feasibility, costs, and technology needed to establish a real-time earthquake monitoring (RTEM) system. The panel, drafted by the National Academy of Science's Committee on Seismology, has presented its findings in Real-Time Earthquake Monitoring. The recently released report states that “present technology is entirely capable of recording and processing data so as to provide real-time information, enabling people to mitigate somewhat the earthquake disaster.” RTEM systems would consist of two parts—an early warning system that would give a few seconds warning before severe shaking, and immediate postquake information within minutes of the quake that would give actual measurements of the magnitude. At this time, however, this type of warning system has not been addressed at the national level for the United States and is not included in the National Earthquake Hazard Reduction Program, according to the report.
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Small discussion of electromagnetic wave anomalies preceding earthquakes
Energy Technology Data Exchange (ETDEWEB)
1980-01-01
Six brief pieces on various aspects of electromagnetic wave anomalies are presented. They cover: earthquake electromagnetic emanations; the use of magnetic induction information for earthquake forecasting; electromagnetic pulse emissions as pre-earthquake indicators; the use of magnetic sensors to determine medium-wavelength field strength for earthquake prediction purposes; magnetic deviation indicators inside reinforced-concrete buildings; and a discussion of the general physical principles involved.
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Geodetic Finite-Fault-based Earthquake Early Warning Performance for Great Earthquakes Worldwide
Ruhl, C. J.; Melgar, D.; Grapenthin, R.; Allen, R. M.
2017-12-01
GNSS-based earthquake early warning (EEW) algorithms estimate fault-finiteness and unsaturated moment magnitude for the largest, most damaging earthquakes. Because large events are infrequent, algorithms are not regularly exercised and insufficiently tested on few available datasets. The Geodetic Alarm System (G-larmS) is a GNSS-based finite-fault algorithm developed as part of the ShakeAlert EEW system in the western US. Performance evaluations using synthetic earthquakes offshore Cascadia showed that G-larmS satisfactorily recovers magnitude and fault length, providing useful alerts 30-40 s after origin time and timely warnings of ground motion for onshore urban areas. An end-to-end test of the ShakeAlert system demonstrated the need for GNSS data to accurately estimate ground motions in real-time. We replay real data from several subduction-zone earthquakes worldwide to demonstrate the value of GNSS-based EEW for the largest, most damaging events. We compare predicted ground acceleration (PGA) from first-alert-solutions with those recorded in major urban areas. In addition, where applicable, we compare observed tsunami heights to those predicted from the G-larmS solutions. We show that finite-fault inversion based on GNSS-data is essential to achieving the goals of EEW.
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A prospective earthquake forecast experiment in the western Pacific
Eberhard, David A. J.; Zechar, J. Douglas; Wiemer, Stefan
2012-09-01
Since the beginning of 2009, the Collaboratory for the Study of Earthquake Predictability (CSEP) has been conducting an earthquake forecast experiment in the western Pacific. This experiment is an extension of the Kagan-Jackson experiments begun 15 years earlier and is a prototype for future global earthquake predictability experiments. At the beginning of each year, seismicity models make a spatially gridded forecast of the number of Mw≥ 5.8 earthquakes expected in the next year. For the three participating statistical models, we analyse the first two years of this experiment. We use likelihood-based metrics to evaluate the consistency of the forecasts with the observed target earthquakes and we apply measures based on Student's t-test and the Wilcoxon signed-rank test to compare the forecasts. Overall, a simple smoothed seismicity model (TripleS) performs the best, but there are some exceptions that indicate continued experiments are vital to fully understand the stability of these models, the robustness of model selection and, more generally, earthquake predictability in this region. We also estimate uncertainties in our results that are caused by uncertainties in earthquake location and seismic moment. Our uncertainty estimates are relatively small and suggest that the evaluation metrics are relatively robust. Finally, we consider the implications of our results for a global earthquake forecast experiment.
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New geological perspectives on earthquake recurrence models
International Nuclear Information System (INIS)
Schwartz, D.P.
1997-01-01
In most areas of the world the record of historical seismicity is too short or uncertain to accurately characterize the future distribution of earthquakes of different sizes in time and space. Most faults have not ruptured once, let alone repeatedly. Ultimately, the ability to correctly forecast the magnitude, location, and probability of future earthquakes depends on how well one can quantify the past behavior of earthquake sources. Paleoseismological trenching of active faults, historical surface ruptures, liquefaction features, and shaking-induced ground deformation structures provides fundamental information on the past behavior of earthquake sources. These studies quantify (a) the timing of individual past earthquakes and fault slip rates, which lead to estimates of recurrence intervals and the development of recurrence models and (b) the amount of displacement during individual events, which allows estimates of the sizes of past earthquakes on a fault. When timing and slip per event are combined with information on fault zone geometry and structure, models that define individual rupture segments can be developed. Paleoseismicity data, in the form of timing and size of past events, provide a window into the driving mechanism of the earthquake engine--the cycle of stress build-up and release
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Thermal regime of the lithosphere and prediction of seismic hazard in the Caspian region
International Nuclear Information System (INIS)
Levin, L.E.; Solodilov, L.N.; Kondorskaya, N.V.; Gasanov, A.G; Panahi, B.M.
2002-01-01
Full text : Prediction of seicmicity is one of elements of ecology hazard warning. In this collective research, it is elaborated in three directions : quantitative estimate of regional faults by level of seismic activity; ascertainment of space position of earthquake risk zones, determination of high seismic potential sites for the period of the next 3-5 years. During elaboration of prediction, it takes into account that peculiar feature all over the is determined by relationship of about 90 percent of earthquake hypocenters and released energy of seismic waves with elactic-brittle ayer of the lithosphere. Concetration of earthquakes epicenters is established predominantly in zones of complex structure of elastic-brittle layer where gradient of it thickness is 20-30 km. Directions of hypocenters migration in the plastic-viscous layer reveal a space position of seismic dangerous zones. All this provides a necessity for generalization of data on location of earthquakes epicenters; determination of their magnitudes, space position of regional faults and heat flow with calculation of thermal regime being made for clarification of the lithosphere and elastic-brittle thickness variations separately. General analysis includes a calculation of released seismic wave energy and determination of peculiar features of its distribution in the entire region and also studies of hypocenters migration in the plastic-viscous layer of the litosphere in time.
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Physics of Earthquake Rupture Propagation
Xu, Shiqing; Fukuyama, Eiichi; Sagy, Amir; Doan, Mai-Linh
2018-05-01
A comprehensive understanding of earthquake rupture propagation requires the study of not only the sudden release of elastic strain energy during co-seismic slip, but also of other processes that operate at a variety of spatiotemporal scales. For example, the accumulation of the elastic strain energy usually takes decades to hundreds of years, and rupture propagation and termination modify the bulk properties of the surrounding medium that can influence the behavior of future earthquakes. To share recent findings in the multiscale investigation of earthquake rupture propagation, we held a session entitled "Physics of Earthquake Rupture Propagation" during the 2016 American Geophysical Union (AGU) Fall Meeting in San Francisco. The session included 46 poster and 32 oral presentations, reporting observations of natural earthquakes, numerical and experimental simulations of earthquake ruptures, and studies of earthquake fault friction. These presentations and discussions during and after the session suggested a need to document more formally the research findings, particularly new observations and views different from conventional ones, complexities in fault zone properties and loading conditions, the diversity of fault slip modes and their interactions, the evaluation of observational and model uncertainties, and comparison between empirical and physics-based models. Therefore, we organize this Special Issue (SI) of Tectonophysics under the same title as our AGU session, hoping to inspire future investigations. Eighteen articles (marked with "this issue") are included in this SI and grouped into the following six categories.
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VLF/LF Radio Sounding of Ionospheric Perturbations Associated with Earthquakes
Directory of Open Access Journals (Sweden)
Masashi Hayakawa
2007-07-01
Full Text Available It is recently recognized that the ionosphere is very sensitive to seismic effects,and the detection of ionospheric perturbations associated with earthquakes, seems to bevery promising for short-term earthquake prediction. We have proposed a possible use ofVLF/LF (very low frequency (3-30 kHz /low frequency (30-300 kHz radio sounding ofthe seismo-ionospheric perturbations. A brief history of the use of subionospheric VLF/LFpropagation for the short-term earthquake prediction is given, followed by a significantfinding of ionospheric perturbation for the Kobe earthquake in 1995. After showingprevious VLF/LF results, we present the latest VLF/LF findings; One is the statisticalcorrelation of the ionospheric perturbation with earthquakes and the second is a case studyfor the Sumatra earthquake in December, 2004, indicating the spatical scale and dynamicsof ionospheric perturbation for this earthquake.
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Predictive property models for use in design of controlled release of pesticides
DEFF Research Database (Denmark)
Suné, Nuria Muro; Gani, Rafiqul; Bell, G.
2005-01-01
A model capable of predicting the release of an Active Ingredient (AI) from a specific device would be very useful in the field of pesticide controlled release technology for design purposes. For the release of an AI from a microcapsule a mathematical model is briefly presented here, as an introd...
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Real-time earthquake source imaging: An offline test for the 2011 Tohoku earthquake
Zhang, Yong; Wang, Rongjiang; Zschau, Jochen; Parolai, Stefano; Dahm, Torsten
2014-05-01
In recent decades, great efforts have been expended in real-time seismology aiming at earthquake and tsunami early warning. One of the most important issues is the real-time assessment of earthquake rupture processes using near-field seismogeodetic networks. Currently, earthquake early warning systems are mostly based on the rapid estimate of P-wave magnitude, which contains generally large uncertainties and the known saturation problem. In the case of the 2011 Mw9.0 Tohoku earthquake, JMA (Japan Meteorological Agency) released the first warning of the event with M7.2 after 25 s. The following updates of the magnitude even decreased to M6.3-6.6. Finally, the magnitude estimate stabilized at M8.1 after about two minutes. This led consequently to the underestimated tsunami heights. By using the newly developed Iterative Deconvolution and Stacking (IDS) method for automatic source imaging, we demonstrate an offline test for the real-time analysis of the strong-motion and GPS seismograms of the 2011 Tohoku earthquake. The results show that we had been theoretically able to image the complex rupture process of the 2011 Tohoku earthquake automatically soon after or even during the rupture process. In general, what had happened on the fault could be robustly imaged with a time delay of about 30 s by using either the strong-motion (KiK-net) or the GPS (GEONET) real-time data. This implies that the new real-time source imaging technique is helpful to reduce false and missing warnings, and therefore should play an important role in future tsunami early warning and earthquake rapid response systems.
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Countermeasures to earthquakes in nuclear plants
International Nuclear Information System (INIS)
Sato, Kazuhide
1979-01-01
The contribution of atomic energy to mankind is unmeasured, but the danger of radioactivity is a special thing. Therefore in the design of nuclear power plants, the safety has been regarded as important, and in Japan where earthquakes occur frequently, the countermeasures to earthquakes have been incorporated in the examination of safety naturally. The radioactive substances handled in nuclear power stations and spent fuel reprocessing plants are briefly explained. The occurrence of earthquakes cannot be predicted effectively, and the disaster due to earthquakes is apt to be remarkably large. In nuclear plants, the prevention of damage in the facilities and the maintenance of the functions are required at the time of earthquakes. Regarding the location of nuclear plants, the history of earthquakes, the possible magnitude of earthquakes, the properties of ground and the position of nuclear plants should be examined. After the place of installation has been decided, the earthquake used for design is selected, evaluating live faults and determining the standard earthquakes. As the fundamentals of aseismatic design, the classification according to importance, the earthquakes for design corresponding to the classes of importance, the combination of loads and allowable stress are explained. (Kako, I.)
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International Nuclear Information System (INIS)
Purcaru, G.
2002-01-01
The occurrence patterns of large/great earthquakes at subduction zone interface and in-slab are complex in the space-time dynamics, and make even long-term forecasts very difficult. For some favourable cases where a predictive (empirical) law was found successful predictions were possible (eg. Aleutians, Kuriles, etc). For the large Romanian events (M > 6.7), occurring in the Vrancea seismic slab below 60 km, Purcaru (1974) first found the law of the occurrence time and magnitude: the law of 'quasicycles' and 'supercycles', for large and largest events (M > 7.25), respectively. The quantitative model of Purcaru with these seismic cycles has three time-bands (periods of large earthquakes)/century, discovered using the earthquake history (1100-1973) (however incomplete) of large Vrancea earthquakes for which M was initially estimated (Purcaru, 1974, 1979). Our long-term prediction model is essentially quasideterministic, it predicts uniquely the time and magnitude; since is not strict deterministic the forecasting is interval valued. It predicted the next large earthquake in 1980 in the 3rd time-band (1970-1990), and which occurred in 1977 (M7.1, M w 7.5). The prediction was successful, in long-term sense. We discuss the unpredicted events in 1986 and 1990. Since the laws are phenomenological, we give their physical foundation based on the large scale of rupture zone (RZ) and subscale of the rupture process (RP). First results show that: (1) the 1940 event (h=122 km) ruptured the lower part of the oceanic slab entirely along strike, and down dip, and similarly for 1977 but its upper part, (2) the RZ of 1977 and 1990 events overlap and the first asperity of 1977 event was rebroken in 1990. This shows the size of the events strongly depends on RZ, asperity size/strength and, thus on the failure stress level (FSL), but not on depth, (3) when FSL of high strength (HS) larger zones is critical largest events (eg. 1802, 1940) occur, thus explaining the supercyles (the 1940
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International Nuclear Information System (INIS)
Zhang, Huaizhen; Chi, Tianhe; Liu, Tianyue; Wang, Wei; Yang, Lina; Zhao, Yuan; Shao, Jing; Yao, Xiaojing; Fan, Jianrong
2014-01-01
Debris flow is a common hazard in the Wenchuan earthquake area. Collapse and Landslide Regions (CLR), caused by earthquakes, could be located from Remote Sensing images. CLR are the direct material source regions for debris flow. The Spatial Distribution of Collapse and Landslide Regions (SDCLR) strongly impact debris-flow formation. In order to depict SDCLR, we referred to Strahler's Hypsometric analysis method and developed 3 functional models to depict SDCLR quantitatively. These models mainly depict SDCLR relative to altitude, basin mouth and main gullies of debris flow. We used the integral of functions as the spatial parameters of SDCLR and these parameters were employed during the process of debris-flows scale predictions. Grouping-occurring debris-flows triggered by the rainstorm, which occurred on September 24th 2008 in Beichuan County, Sichuan province China, were selected to build the empirical equations for debris-flows scale predictions. Given the existing data, only debris-flows runout zone parameters (Max. runout distance L and Lateral width B) were estimated in this paper. The results indicate that the predicted results were more accurate when the spatial parameters were used. Accordingly, we suggest spatial parameters of SDCLR should be considered in the process of debris-flows scale prediction and proposed several strategies to prevent debris flow in the future
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Initiation process of earthquakes and its implications for seismic hazard reduction strategy.
Kanamori, H
1996-04-30
For the average citizen and the public, "earthquake prediction" means "short-term prediction," a prediction of a specific earthquake on a relatively short time scale. Such prediction must specify the time, place, and magnitude of the earthquake in question with sufficiently high reliability. For this type of prediction, one must rely on some short-term precursors. Examinations of strain changes just before large earthquakes suggest that consistent detection of such precursory strain changes cannot be expected. Other precursory phenomena such as foreshocks and nonseismological anomalies do not occur consistently either. Thus, reliable short-term prediction would be very difficult. Although short-term predictions with large uncertainties could be useful for some areas if their social and economic environments can tolerate false alarms, such predictions would be impractical for most modern industrialized cities. A strategy for effective seismic hazard reduction is to take full advantage of the recent technical advancements in seismology, computers, and communication. In highly industrialized communities, rapid earthquake information is critically important for emergency services agencies, utilities, communications, financial companies, and media to make quick reports and damage estimates and to determine where emergency response is most needed. Long-term forecast, or prognosis, of earthquakes is important for development of realistic building codes, retrofitting existing structures, and land-use planning, but the distinction between short-term and long-term predictions needs to be clearly communicated to the public to avoid misunderstanding.
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A Geodynamic Study of Active Crustal Deformation and Earthquakes in North China
Yang, Y.; Liu, M.
2005-12-01
North China is part of the Archaean Sino-Korean craton, yet today it is a region of intense crustal deformation and earthquakes, including 21 M >=7.0 events since 512 AD. More than half of the large events occurred within the Fen-Wei rift system surrounding the stable Ordos plateau; the largest events (M >=7.3) show a sequential southward migration along the rift. However, since 1695 the Fen-Wei rift has became seismically dormant, while seismicity seems having shifted eastward to the North China plain, marked by the 1996 Tangshan earthquake (M=7.8). We have developed a 3D viscoelastic geodynamic model to study the cause of seismicity and its spatial-temporal pattern in North China. Constrained by crustal kinematics from GPS and neotectonic data, the model shows high deviatoric stress in the North China crust, resulting mainly from compression of the expanding Tibetan Plateau and resistance from the stable Siberian block. Within North China seismicity is largely controlled by lateral heterogeneity of lithospheric structures, which explains the concentration of seismicity in the Fen-Wei rift. Our results show that stress triggering may have contributed to the sequential migration of large events along the rift, and the release and migration of stress and strain energy from these large events may partially explain the intense seismicity in the North China plain in the past 300 years. Comparing the predicted long-term spatial pattern of strain energy with seismic energy release provides some insights of potential earthquake risks in North China.
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Statistical distributions of earthquakes and related non-linear features in seismic waves
International Nuclear Information System (INIS)
Apostol, B.-F.
2006-01-01
A few basic facts in the science of the earthquakes are briefly reviewed. An accumulation, or growth, model is put forward for the focal mechanisms and the critical focal zone of the earthquakes, which relates the earthquake average recurrence time to the released seismic energy. The temporal statistical distribution for average recurrence time is introduced for earthquakes, and, on this basis, the Omori-type distribution in energy is derived, as well as the distribution in magnitude, by making use of the semi-empirical Gutenberg-Richter law relating seismic energy to earthquake magnitude. On geometric grounds, the accumulation model suggests the value r = 1/3 for the Omori parameter in the power-law of energy distribution, which leads to β = 1,17 for the coefficient in the Gutenberg-Richter recurrence law, in fair agreement with the statistical analysis of the empirical data. Making use of this value, the empirical Bath's law is discussed for the average magnitude of the aftershocks (which is 1.2 less than the magnitude of the main seismic shock), by assuming that the aftershocks are relaxation events of the seismic zone. The time distribution of the earthquakes with a fixed average recurrence time is also derived, the earthquake occurrence prediction is discussed by means of the average recurrence time and the seismicity rate, and application of this discussion to the seismic region Vrancea, Romania, is outlined. Finally, a special effect of non-linear behaviour of the seismic waves is discussed, by describing an exact solution derived recently for the elastic waves equation with cubic anharmonicities, its relevance, and its connection to the approximate quasi-plane waves picture. The properties of the seismic activity accompanying a main seismic shock, both like foreshocks and aftershocks, are relegated to forthcoming publications. (author)
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Retrospective evaluation of the five-year and ten-year CSEP-Italy earthquake forecasts
Directory of Open Access Journals (Sweden)
Stefan Wiemer
2010-11-01
Full Text Available On August 1, 2009, the global Collaboratory for the Study of Earthquake Predictability (CSEP launched a prospective and comparative earthquake predictability experiment in Italy. The goal of this CSEP-Italy experiment is to test earthquake occurrence hypotheses that have been formalized as probabilistic earthquake forecasts over temporal scales that range from days to years. In the first round of forecast submissions, members of the CSEP-Italy Working Group presented 18 five-year and ten-year earthquake forecasts to the European CSEP Testing Center at ETH Zurich. We have considered here the twelve time-independent earthquake forecasts among this set, and evaluated them with respect to past seismicity data from two Italian earthquake catalogs. We present the results of the tests that measure the consistencies of the forecasts according to past observations. As well as being an evaluation of the time-independent forecasts submitted, this exercise provides insight into a number of important issues in predictability experiments with regard to the specification of the forecasts, the performance of the tests, and the trade-off between robustness of results and experiment duration. We conclude with suggestions for the design of future earthquake predictability experiments.
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Relaxation creep model of impending earthquake
Energy Technology Data Exchange (ETDEWEB)
Morgounov, V. A. [Russian Academy of Sciences, Institute of Physics of the Earth, Moscow (Russian Federation)
2001-04-01
The alternative view of the current status and perspective of seismic prediction studies is discussed. In the problem of the ascertainment of the uncertainty relation Cognoscibility-Unpredictability of Earthquakes, priorities of works on short-term earthquake prediction are defined due to the advantage that the final stage of nucleation of earthquake is characterized by a substantial activation of the process while its strain rate increases by the orders of magnitude and considerably increased signal-to-noise ratio. Based on the creep phenomenon under stress relaxation conditions, a model is proposed to explain different images of precursors of impending tectonic earthquakes. The onset of tertiary creep appears to correspond to the onset of instability and inevitably fails unless it unloaded. At this stage, the process acquires the self-regulating character to the greatest extent the property of irreversibility, one of the important components of prediction reliability. Data in situ suggest a principal possibility to diagnose the process of preparation by ground measurements of acoustic and electromagnetic emission in the rocks under constant strain in the condition of self-relaxed stress until the moment of fracture are discussed in context. It was obtained that electromagnetic emission precedes but does not accompany the phase of macrocrak development.
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Modelling earth current precursors in earthquake prediction
Directory of Open Access Journals (Sweden)
R. Di Maio
1997-06-01
Full Text Available This paper deals with the theory of earth current precursors of earthquake. A dilatancy-diffusion-polarization model is proposed to explain the anomalies of the electric potential, which are observed on the ground surface prior to some earthquakes. The electric polarization is believed to be the electrokinetic effect due to the invasion of fluids into new pores, which are opened inside a stressed-dilated rock body. The time and space variation of the distribution of the electric potential in a layered earth as well as in a faulted half-space is studied in detail. It results that the surface response depends on the underground conductivity distribution and on the relative disposition of the measuring dipole with respect to the buried bipole source. A field procedure based on the use of an areal layout of the recording sites is proposed, in order to obtain the most complete information on the time and space evolution of the precursory phenomena in any given seismic region.
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Earthquake prediction analysis based on empirical seismic rate: the M8 algorithm
Molchan, G.; Romashkova, L.
2010-12-01
The quality of space-time earthquake prediction is usually characterized by a 2-D error diagram (n, τ), where n is the fraction of failures-to-predict and τ is the local rate of alarm averaged in space. The most reasonable averaging measure for analysis of a prediction strategy is the normalized rate of target events λ(dg) in a subarea dg. In that case the quantity H = 1 - (n + τ) determines the prediction capability of the strategy. The uncertainty of λ(dg) causes difficulties in estimating H and the statistical significance, α, of prediction results. We investigate this problem theoretically and show how the uncertainty of the measure can be taken into account in two situations, viz., the estimation of α and the construction of a confidence zone for the (n, τ)-parameters of the random strategies. We use our approach to analyse the results from prediction of M >= 8.0 events by the M8 method for the period 1985-2009 (the M8.0+ test). The model of λ(dg) based on the events Mw >= 5.5, 1977-2004, and the magnitude range of target events 8.0 <= M < 8.5 are considered as basic to this M8 analysis. We find the point and upper estimates of α and show that they are still unstable because the number of target events in the experiment is small. However, our results argue in favour of non-triviality of the M8 prediction algorithm.
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Testing the accelerating moment release (AMR) hypothesis in areas of high stress
Guilhem, Aurélie; Bürgmann, Roland; Freed, Andrew M.; Ali, Syed Tabrez
2013-11-01
Several retrospective analyses have proposed that significant increases in moment release occurred prior to many large earthquakes of recent times. However, the finding of accelerating moment release (AMR) strongly depends on the choice of three parameters: (1) magnitude range, (2) area being considered surrounding the events and (3) the time period prior to the large earthquakes. Consequently, the AMR analysis has been criticized as being a posteriori data-fitting exercise with no new predictive power. As AMR has been hypothesized to relate to changes in the state of stress around the eventual epicentre, we compare here AMR results to models of stress accumulation in California. Instead of assuming a complete stress drop on all surrounding fault segments implied by a back-slip stress lobe method, we consider that stress evolves dynamically, punctuated by the occurrence of earthquakes, and governed by the elastic and viscous properties of the lithosphere. We study the seismicity of southern California and extract events for AMR calculations following the systematic approach employed in previous studies. We present several sensitivity tests of the method, as well as grid-search analyses over the region between 1955 and 2005 using fixed magnitude range, radius of the search area and period of time. The results are compared to the occurrence of large events and to maps of Coulomb stress changes. The Coulomb stress maps are compiled using the coseismic stress from all M > 7.0 earthquakes since 1812, their subsequent post-seismic relaxation, and the interseismic strain accumulation. We find no convincing correlation of seismicity rate changes in recent decades with areas of high stress that would support the AMR hypothesis. Furthermore, this indicates limited utility for practical earthquake hazard analysis in southern California, and possibly other regions.
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Prediction of organic combined sewer sediment release and transport
Seco, Raquel Irene; Schellart, Alma Neeltje Antonia; Gómez Valentín, Manuel; Tait, Simon
2018-01-01
Accurate predictions of sediment loads released by sewer overflow discharges are important for being able to provide protection to vulnerable receiving waters. These predictions are sensitive to the estimated sediment characteristics and on the site conditions of in-pipe deposit formation. Their application without a detailed analysis and understanding of the initial conditions under which in-sewer deposits were formed normally results in very poor estimations. In this study, in-sewer sedimen...
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Predictions of PuO2 and tracer compound release from ISV melts
International Nuclear Information System (INIS)
Cronenberg, A.W.; Callow, R.A.
1992-04-01
Two field tests were conducted at the Idaho National Engineering Laboratory (INEL) to assess in situ vitrification (ISV) suitability for long-term stabilization of buried radioactive waste. Both tests contained rare-earth oxide tracers (DY 2 O 3 , Yb 2 O 3 , and Tb 4 O 7 ) to simulate the presence of plutonium in the form of PuO 2 . In the first test, Intermediate Field Test (IFT)-l, approximately 4-% release of tracer material occurred during soil melting and associated off-gassing, while essentially nil release was observed for the second experiment (IFT-2) for which off-gassing was much reduced. This report presents an evaluation of the IFT test data in terms of governing release processes. Prediction of tracer release during ISV melting centered on an assessment of three potential transport mechanisms, (a) tracer diffusion through stagnant pool, (b) tracer transport by convective currents, and (c) tracer carry-off by escaping gas bubbles. Analysis indicates that tracer release by escaping gas is the dominant release mechanism, which is consistent with video records of gas bubble escape from the ISV melt surface. Quantitative mass transport predictions were also made for the IFT-I test conditions, indicating similarity between the 4-% release data and calculational results at viscosities of ∼ poise and tracer diffusivities of ∼10 -6 CM 2 /s. Since PuO 2 has similar chemical and transport (diffusivity) properties as the rare-earth tracers used in the rare earth tracers used in the IFT experiments, release of PuO 2 is predicted for similar off-gassing conditions. Reduced off-gassing during ISV would thus be expected to improve the overall retention of heavy-oxides within vitrified soil
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A 'new generation' earthquake catalogue
Directory of Open Access Journals (Sweden)
E. Boschi
2000-06-01
Full Text Available In 1995, we published the first release of the Catalogo dei Forti Terremoti in Italia, 461 a.C. - 1980, in Italian (Boschi et al., 1995. Two years later this was followed by a second release, again in Italian, that included more earthquakes, more accurate research and a longer time span (461 B.C. to 1990 (Boschi et al., 1997. Aware that the record of Italian historical seismicity is probably the most extensive of the whole world, and hence that our catalogue could be of interest for a wider interna-tional readership, Italian was clearly not the appropriate language to share this experience with colleagues from foreign countries. Three years after publication of the second release therefore, and after much additional research and fine tuning of methodologies and algorithms, I am proud to introduce this third release in English. All the tools and accessories have been translated along with the texts describing the development of the underlying research strategies and current contents. The English title is Catalogue of Strong Italian Earthquakes, 461 B.C. to 1997. This Preface briefly describes the scientific context within which the Catalogue of Strong Italian Earthquakes was conceived and progressively developed. The catalogue is perhaps the most impor-tant outcome of a well-established joint project between the Istituto Nazionale di Geofisica, the leading Italian institute for basic and applied research in seismology and solid earth geophysics, and SGA (Storia Geofisica Ambiente, a private firm specialising in the historical investigation and systematisation of natural phenomena. In her contribution "Method of investigation, typology and taxonomy of the basic data: navigating between seismic effects and historical contexts", Emanuela Guidoboni outlines the general framework of modern historical seismology, its complex relation with instrumental seismology on the one hand and historical research on the other. This presentation also highlights
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Global earthquake fatalities and population
Holzer, Thomas L.; Savage, James C.
2013-01-01
Modern global earthquake fatalities can be separated into two components: (1) fatalities from an approximately constant annual background rate that is independent of world population growth and (2) fatalities caused by earthquakes with large human death tolls, the frequency of which is dependent on world population. Earthquakes with death tolls greater than 100,000 (and 50,000) have increased with world population and obey a nonstationary Poisson distribution with rate proportional to population. We predict that the number of earthquakes with death tolls greater than 100,000 (50,000) will increase in the 21st century to 8.7±3.3 (20.5±4.3) from 4 (7) observed in the 20th century if world population reaches 10.1 billion in 2100. Combining fatalities caused by the background rate with fatalities caused by catastrophic earthquakes (>100,000 fatalities) indicates global fatalities in the 21st century will be 2.57±0.64 million if the average post-1900 death toll for catastrophic earthquakes (193,000) is assumed.
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Precursory earthquakes of the 1943 eruption of Paricutin volcano, Michoacan, Mexico
Yokoyama, I.; de la Cruz-Reyna, S.
1990-12-01
Paricutin volcano is a monogenetic volcano whose birth and growth were observed by modern volcanological techniques. At the time of its birth in 1943, the seismic activity in central Mexico was mainly recorded by the Wiechert seismographs at the Tacubaya seismic station in Mexico City about 320 km east of the volcano area. In this paper we aim to find any characteristics of precursory earthquakes of the monogenetic eruption. Though there are limits in the available information, such as imprecise location of hypocenters and lack of earthquake data with magnitudes under 3.0. The available data show that the first precursory earthquake occurred on January 7, 1943, with a magnitude of 4.4. Subsequently, 21 earthquakes ranging from 3.2 to 4.5 in magnitude occurred before the outbreak of the eruption on February 20. The (S - P) durations of the precursory earthquakes do not show any systematic changes within the observational errors. The hypocenters were rather shallow and did not migrate. The precursory earthquakes had a characteristic tectonic signature, which was retained through the whole period of activity. However, the spectra of the P-waves of the Paricutin earthquakes show minor differences from those of tectonic earthquakes. This fact helped in the identification of Paricutin earthquakes. Except for the first shock, the maximum earthquake magnitudes show an increasing tendency with time towards the outbreak. The total seismic energy released by the precursory earthquakes amounted to 2 × 10 19 ergs. Considering that statistically there is a threshold of cumulative seismic energy release (10 17-18ergs) by precursory earthquakes in polygenetic volcanoes erupting after long quiescence, the above cumulative energy is exceptionally large. This suggests that a monogenetic volcano may need much more energy to clear the way of magma passage to the earth surface than a polygenetic one. The magma ascent before the outbreak of Paricutin volcano is interpretable by a model
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Earthquake number forecasts testing
Kagan, Yan Y.
2017-10-01
We study the distributions of earthquake numbers in two global earthquake catalogues: Global Centroid-Moment Tensor and Preliminary Determinations of Epicenters. The properties of these distributions are especially required to develop the number test for our forecasts of future seismic activity rate, tested by the Collaboratory for Study of Earthquake Predictability (CSEP). A common assumption, as used in the CSEP tests, is that the numbers are described by the Poisson distribution. It is clear, however, that the Poisson assumption for the earthquake number distribution is incorrect, especially for the catalogues with a lower magnitude threshold. In contrast to the one-parameter Poisson distribution so widely used to describe earthquake occurrences, the negative-binomial distribution (NBD) has two parameters. The second parameter can be used to characterize the clustering or overdispersion of a process. We also introduce and study a more complex three-parameter beta negative-binomial distribution. We investigate the dependence of parameters for both Poisson and NBD distributions on the catalogue magnitude threshold and on temporal subdivision of catalogue duration. First, we study whether the Poisson law can be statistically rejected for various catalogue subdivisions. We find that for most cases of interest, the Poisson distribution can be shown to be rejected statistically at a high significance level in favour of the NBD. Thereafter, we investigate whether these distributions fit the observed distributions of seismicity. For this purpose, we study upper statistical moments of earthquake numbers (skewness and kurtosis) and compare them to the theoretical values for both distributions. Empirical values for the skewness and the kurtosis increase for the smaller magnitude threshold and increase with even greater intensity for small temporal subdivision of catalogues. The Poisson distribution for large rate values approaches the Gaussian law, therefore its skewness
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Measuring the effectiveness of earthquake forecasting in insurance strategies
Mignan, A.; Muir-Wood, R.
2009-04-01
Given the difficulty of judging whether the skill of a particular methodology of earthquake forecasts is offset by the inevitable false alarms and missed predictions, it is important to find a means to weigh the successes and failures according to a common currency. Rather than judge subjectively the relative costs and benefits of predictions, we develop a simple method to determine if the use of earthquake forecasts can increase the profitability of active financial risk management strategies employed in standard insurance procedures. Three types of risk management transactions are employed: (1) insurance underwriting, (2) reinsurance purchasing and (3) investment in CAT bonds. For each case premiums are collected based on modelled technical risk costs and losses are modelled for the portfolio in force at the time of the earthquake. A set of predetermined actions follow from the announcement of any change in earthquake hazard, so that, for each earthquake forecaster, the financial performance of an active risk management strategy can be compared with the equivalent passive strategy in which no notice is taken of earthquake forecasts. Overall performance can be tracked through time to determine which strategy gives the best long term financial performance. This will be determined by whether the skill in forecasting the location and timing of a significant earthquake (where loss is avoided) is outweighed by false predictions (when no premium is collected). This methodology is to be tested in California, where catastrophe modeling is reasonably mature and where a number of researchers issue earthquake forecasts.
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Radon anomalies prior to earthquakes (1). Review of previous studies
International Nuclear Information System (INIS)
Ishikawa, Tetsuo; Tokonami, Shinji; Yasuoka, Yumi; Shinogi, Masaki; Nagahama, Hiroyuki; Omori, Yasutaka; Kawada, Yusuke
2008-01-01
The relationship between radon anomalies and earthquakes has been studied for more than 30 years. However, most of the studies dealt with radon in soil gas or in groundwater. Before the 1995 Hyogoken-Nanbu earthquake, an anomalous increase of atmospheric radon was observed at Kobe Pharmaceutical University. The increase was well fitted with a mathematical model related to earthquake fault dynamics. This paper reports the significance of this observation, reviewing previous studies on radon anomaly before earthquakes. Groundwater/soil radon measurements for earthquake prediction began in 1970's in Japan as well as foreign countries. One of the most famous studies in Japan is groundwater radon anomaly before the 1978 Izu-Oshima-kinkai earthquake. We have recognized the significance of radon in earthquake prediction research, but recently its limitation was also pointed out. Some researchers are looking for a better indicator for precursors; simultaneous measurements of radon and other gases are new trials in recent studies. Contrary to soil/groundwater radon, we have not paid much attention to atmospheric radon before earthquakes. However, it might be possible to detect precursors in atmospheric radon before a large earthquake. In the next issues, we will discuss the details of the anomalous atmospheric radon data observed before the Hyogoken-Nanbu earthquake. (author)
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Fault roughness and strength heterogeneity control earthquake size and stress drop
Zielke, Olaf
2017-01-13
An earthquake\\'s stress drop is related to the frictional breakdown during sliding and constitutes a fundamental quantity of the rupture process. High-speed laboratory friction experiments that emulate the rupture process imply stress drop values that greatly exceed those commonly reported for natural earthquakes. We hypothesize that this stress drop discrepancy is due to fault-surface roughness and strength heterogeneity: an earthquake\\'s moment release and its recurrence probability depend not only on stress drop and rupture dimension but also on the geometric roughness of the ruptured fault and the location of failing strength asperities along it. Using large-scale numerical simulations for earthquake ruptures under varying roughness and strength conditions, we verify our hypothesis, showing that smoother faults may generate larger earthquakes than rougher faults under identical tectonic loading conditions. We further discuss the potential impact of fault roughness on earthquake recurrence probability. This finding provides important information, also for seismic hazard analysis.
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Toward real-time regional earthquake simulation of Taiwan earthquakes
Lee, S.; Liu, Q.; Tromp, J.; Komatitsch, D.; Liang, W.; Huang, B.
2013-12-01
We developed a Real-time Online earthquake Simulation system (ROS) to simulate regional earthquakes in Taiwan. The ROS uses a centroid moment tensor solution of seismic events from a Real-time Moment Tensor monitoring system (RMT), which provides all the point source parameters including the event origin time, hypocentral location, moment magnitude and focal mechanism within 2 minutes after the occurrence of an earthquake. Then, all of the source parameters are automatically forwarded to the ROS to perform an earthquake simulation, which is based on a spectral-element method (SEM). We have improved SEM mesh quality by introducing a thin high-resolution mesh layer near the surface to accommodate steep and rapidly varying topography. The mesh for the shallow sedimentary basin is adjusted to reflect its complex geometry and sharp lateral velocity contrasts. The grid resolution at the surface is about 545 m, which is sufficient to resolve topography and tomography data for simulations accurate up to 1.0 Hz. The ROS is also an infrastructural service, making online earthquake simulation feasible. Users can conduct their own earthquake simulation by providing a set of source parameters through the ROS webpage. For visualization, a ShakeMovie and ShakeMap are produced during the simulation. The time needed for one event is roughly 3 minutes for a 70 sec ground motion simulation. The ROS is operated online at the Institute of Earth Sciences, Academia Sinica (http://ros.earth.sinica.edu.tw/). Our long-term goal for the ROS system is to contribute to public earth science outreach and to realize seismic ground motion prediction in real-time.
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ELER software - a new tool for urban earthquake loss assessment
Hancilar, U.; Tuzun, C.; Yenidogan, C.; Erdik, M.
2010-12-01
Rapid loss estimation after potentially damaging earthquakes is critical for effective emergency response and public information. A methodology and software package, ELER-Earthquake Loss Estimation Routine, for rapid estimation of earthquake shaking and losses throughout the Euro-Mediterranean region was developed under the Joint Research Activity-3 (JRA3) of the EC FP6 Project entitled "Network of Research Infrastructures for European Seismology-NERIES". Recently, a new version (v2.0) of ELER software has been released. The multi-level methodology developed is capable of incorporating regional variability and uncertainty originating from ground motion predictions, fault finiteness, site modifications, inventory of physical and social elements subjected to earthquake hazard and the associated vulnerability relationships. Although primarily intended for quasi real-time estimation of earthquake shaking and losses, the routine is also equally capable of incorporating scenario-based earthquake loss assessments. This paper introduces the urban earthquake loss assessment module (Level 2) of the ELER software which makes use of the most detailed inventory databases of physical and social elements at risk in combination with the analytical vulnerability relationships and building damage-related casualty vulnerability models for the estimation of building damage and casualty distributions, respectively. Spectral capacity-based loss assessment methodology and its vital components are presented. The analysis methods of the Level 2 module, i.e. Capacity Spectrum Method (ATC-40, 1996), Modified Acceleration-Displacement Response Spectrum Method (FEMA 440, 2005), Reduction Factor Method (Fajfar, 2000) and Coefficient Method (ASCE 41-06, 2006), are applied to the selected building types for validation and verification purposes. The damage estimates are compared to the results obtained from the other studies available in the literature, i.e. SELENA v4.0 (Molina et al., 2008) and
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GIS BASED SYSTEM FOR POST-EARTHQUAKE CRISIS MANAGMENT USING CELLULAR NETWORK
Raeesi, M.; Sadeghi-Niaraki, A.
2013-01-01
Earthquakes are among the most destructive natural disasters. Earthquakes happen mainly near the edges of tectonic plates, but they may happen just about anywhere. Earthquakes cannot be predicted. Quick response after disasters, like earthquake, decreases loss of life and costs. Massive earthquakes often cause structures to collapse, trapping victims under dense rubble for long periods of time. After the earthquake and destroyed some areas, several teams are sent to find the location of the d...
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Predicting red wolf release success in the southeastern United States
van Manen, Frank T.; Crawford, Barron A.; Clark, Joseph D.
2000-01-01
Although the red wolf (Canis rufus) was once found throughout the southeastern United States, indiscriminate killing and habitat destruction reduced its range to a small section of coastal Texas and Louisiana. Wolves trapped from 1973 to 1980 were taken to establish a captive breeding program that was used to repatriate 2 mainland and 3 island red wolf populations. We collected data from 320 red wolf releases in these areas and classified each as a success or failure based on survival and reproductive criteria, and whether recaptures were necessary to resolve conflicts with humans. We evaluated the relations between release success and conditions at the release sites, characteristics of released wolves, and release procedures. Although <44% of the variation in release success was explained, model performance based on jackknife tests indicated a 72-80% correct prediction rate for the 4 operational models we developed. The models indicated that success was associated with human influences on the landscape and the level of wolf habituation to humans prior to release. We applied the models to 31 prospective areas for wolf repatriation and calculated an index of release success for each area. Decision-makers can use these models to objectively rank prospective release areas and compare strengths and weaknesses of each.
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Retrospective Evaluation of the Five-Year and Ten-Year CSEP-Italy Earthquake Forecasts
Werner, M. J.; Zechar, J. D.; Marzocchi, W.; Wiemer, S.
2010-01-01
On 1 August 2009, the global Collaboratory for the Study of Earthquake Predictability (CSEP) launched a prospective and comparative earthquake predictability experiment in Italy. The goal of the CSEP-Italy experiment is to test earthquake occurrence hypotheses that have been formalized as probabilistic earthquake forecasts over temporal scales that range from days to years. In the first round of forecast submissions, members of the CSEP-Italy Working Group presented eighteen five-year and ten...
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Predicting masking release of lateralized speech
DEFF Research Database (Denmark)
Chabot-Leclerc, Alexandre; MacDonald, Ewen; Dau, Torsten
2016-01-01
. The largest masking release (MR) was observed when all maskers were on the opposite side of the target. The data in the conditions containing only energetic masking and modulation masking could be accounted for using a binaural extension of the speech-based envelope power spectrum model [sEPSM; Jørgensen et...... al., 2013, J. Acoust. Soc. Am. 130], which uses a short-term equalization-cancellation process to model binaural unmasking. In the conditions where informational masking (IM) was involved, the predicted SRTs were lower than the measured values because the model is blind to confusions experienced...
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Lu, Kunquan; Cao, Zexian; Hou, Meiying; Jiang, Zehui; Shen, Rong; Wang, Qiang; Sun, Gang; Liu, Jixing
2018-03-01
earthquakes and deep-focus earthquakes are the energy release caused by the slip or flow of rocks following a jamming-unjamming transition. (4) The energetics and impending precursors of earthquake: The energy of earthquake is the kinetic energy released from the jamming-unjamming transition. Calculation shows that the kinetic energy of seismic rock sliding is comparable with the total work demanded for rocks’ shear failure and overcoming of frictional resistance. There will be no heat flow paradox. Meanwhile, some valuable seismic precursors are likely to be identified by observing the accumulation of additional tectonic forces, local geological changes, as well as the effect of rock state changes, etc.
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Earthquake chemical precursors in groundwater: a review
Paudel, Shukra Raj; Banjara, Sushant Prasad; Wagle, Amrita; Freund, Friedemann T.
2018-03-01
We review changes in groundwater chemistry as precursory signs for earthquakes. In particular, we discuss pH, total dissolved solids (TDS), electrical conductivity, and dissolved gases in relation to their significance for earthquake prediction or forecasting. These parameters are widely believed to vary in response to seismic and pre-seismic activity. However, the same parameters also vary in response to non-seismic processes. The inability to reliably distinguish between changes caused by seismic or pre-seismic activities from changes caused by non-seismic activities has impeded progress in earthquake science. Short-term earthquake prediction is unlikely to be achieved, however, by pH, TDS, electrical conductivity, and dissolved gas measurements alone. On the other hand, the production of free hydroxyl radicals (•OH), subsequent reactions such as formation of H2O2 and oxidation of As(III) to As(V) in groundwater, have distinctive precursory characteristics. This study deviates from the prevailing mechanical mantra. It addresses earthquake-related non-seismic mechanisms, but focused on the stress-induced electrification of rocks, the generation of positive hole charge carriers and their long-distance propagation through the rock column, plus on electrochemical processes at the rock-water interface.
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Computer-aided and predictive models for design of controlled release of pesticides
DEFF Research Database (Denmark)
Suné, Nuria Muro; Gani, Rafiqul
2004-01-01
In the field of pesticide controlled release technology, a computer based model that can predict the delivery of the Active Ingredient (AI) from fabricated units is important for purposes of product design and marketing. A model for the release of an M from a microcapsule device is presented...... in this paper, together with a specific case study application to highlight its scope and significance. The paper also addresses the need for predictive models and proposes a computer aided modelling framework for achieving it through the development and introduction of reliable and predictive constitutive...... models. A group-contribution based model for one of the constitutive variables (AI solubility in polymers) is presented together with examples of application and validation....
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Antioptimization of earthquake exitation and response
Directory of Open Access Journals (Sweden)
G. Zuccaro
1998-01-01
Full Text Available The paper presents a novel approach to predict the response of earthquake-excited structures. The earthquake excitation is expanded in terms of series of deterministic functions. The coefficients of the series are represented as a point in N-dimensional space. Each available ccelerogram at a certain site is then represented as a point in the above space, modeling the available fragmentary historical data. The minimum volume ellipsoid, containing all points, is constructed. The ellipsoidal models of uncertainty, pertinent to earthquake excitation, are developed. The maximum response of a structure, subjected to the earthquake excitation, within ellipsoidal modeling of the latter, is determined. This procedure of determining least favorable response was termed in the literature (Elishakoff, 1991 as an antioptimization. It appears that under inherent uncertainty of earthquake excitation, antioptimization analysis is a viable alternative to stochastic approach.
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Dolan, James F.; Meade, Brendan J.
2017-12-01
Comparison of preevent geodetic and geologic rates in three large-magnitude (Mw = 7.6-7.9) strike-slip earthquakes reveals a wide range of behaviors. Specifically, geodetic rates of 26-28 mm/yr for the North Anatolian fault along the 1999 MW = 7.6 Izmit rupture are ˜40% faster than Holocene geologic rates. In contrast, geodetic rates of ˜6-8 mm/yr along the Denali fault prior to the 2002 MW = 7.9 Denali earthquake are only approximately half as fast as the latest Pleistocene-Holocene geologic rate of ˜12 mm/yr. In the third example where a sufficiently long pre-earthquake geodetic time series exists, the geodetic and geologic rates along the 2001 MW = 7.8 Kokoxili rupture on the Kunlun fault are approximately equal at ˜11 mm/yr. These results are not readily explicable with extant earthquake-cycle modeling, suggesting that they may instead be due to some combination of regional kinematic fault interactions, temporal variations in the strength of lithospheric-scale shear zones, and/or variations in local relative plate motion rate. Whatever the exact causes of these variable behaviors, these observations indicate that either the ratio of geodetic to geologic rates before an earthquake may not be diagnostic of the time to the next earthquake, as predicted by many rheologically based geodynamic models of earthquake-cycle behavior, or different behaviors characterize different fault systems in a manner that is not yet understood or predictable.
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Adaptively smoothed seismicity earthquake forecasts for Italy
Directory of Open Access Journals (Sweden)
Yan Y. Kagan
2010-11-01
Full Text Available We present a model for estimation of the probabilities of future earthquakes of magnitudes m ≥ 4.95 in Italy. This model is a modified version of that proposed for California, USA, by Helmstetter et al. [2007] and Werner et al. [2010a], and it approximates seismicity using a spatially heterogeneous, temporally homogeneous Poisson point process. The temporal, spatial and magnitude dimensions are entirely decoupled. Magnitudes are independently and identically distributed according to a tapered Gutenberg-Richter magnitude distribution. We have estimated the spatial distribution of future seismicity by smoothing the locations of past earthquakes listed in two Italian catalogs: a short instrumental catalog, and a longer instrumental and historic catalog. The bandwidth of the adaptive spatial kernel is estimated by optimizing the predictive power of the kernel estimate of the spatial earthquake density in retrospective forecasts. When available and reliable, we used small earthquakes of m ≥ 2.95 to reveal active fault structures and 29 probable future epicenters. By calibrating the model with these two catalogs of different durations to create two forecasts, we intend to quantify the loss (or gain of predictability incurred when only a short, but recent, data record is available. Both forecasts were scaled to five and ten years, and have been submitted to the Italian prospective forecasting experiment of the global Collaboratory for the Study of Earthquake Predictability (CSEP. An earlier forecast from the model was submitted by Helmstetter et al. [2007] to the Regional Earthquake Likelihood Model (RELM experiment in California, and with more than half of the five-year experimental period over, the forecast has performed better than the others.
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Statistical aspects and risks of human-caused earthquakes
Klose, C. D.
2013-12-01
The seismological community invests ample human capital and financial resources to research and predict risks associated with earthquakes. Industries such as the insurance and re-insurance sector are equally interested in using probabilistic risk models developed by the scientific community to transfer risks. These models are used to predict expected losses due to naturally occurring earthquakes. But what about the risks associated with human-caused earthquakes? Such risk models are largely absent from both industry and academic discourse. In countries around the world, informed citizens are becoming increasingly aware and concerned that this economic bias is not sustainable for long-term economic growth, environmental and human security. Ultimately, citizens look to their government officials to hold industry accountable. In the Netherlands, for example, the hydrocarbon industry is held accountable for causing earthquakes near Groningen. In Switzerland, geothermal power plants were shut down or suspended because they caused earthquakes in canton Basel and St. Gallen. The public and the private non-extractive industry needs access to information about earthquake risks in connection with sub/urban geoengineeing activities, including natural gas production through fracking, geothermal energy production, carbon sequestration, mining and water irrigation. This presentation illuminates statistical aspects of human-caused earthquakes with respect to different geologic environments. Statistical findings are based on the first catalog of human-caused earthquakes (in Klose 2013). Findings are discussed which include the odds to die during a medium-size earthquake that is set off by geomechanical pollution. Any kind of geoengineering activity causes this type of pollution and increases the likelihood of triggering nearby faults to rupture.
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Earthquake Prediction Analysis Based on Empirical Seismic Rate: The M8 Algorithm
International Nuclear Information System (INIS)
Molchan, G.; Romashkova, L.
2010-07-01
The quality of space-time earthquake prediction is usually characterized by a two-dimensional error diagram (n,τ), where n is the rate of failures-to-predict and τ is the normalized measure of space-time alarm. The most reasonable space measure for analysis of a prediction strategy is the rate of target events λ(dg) in a sub-area dg. In that case the quantity H = 1-(n +τ) determines the prediction capability of the strategy. The uncertainty of λ(dg) causes difficulties in estimating H and the statistical significance, α, of prediction results. We investigate this problem theoretically and show how the uncertainty of the measure can be taken into account in two situations, viz., the estimation of α and the construction of a confidence zone for the (n,τ)-parameters of the random strategies. We use our approach to analyse the results from prediction of M ≥ 8.0 events by the M8 method for the period 1985-2009 (the M8.0+ test). The model of λ(dg) based on the events Mw ≥ 5.5, 1977-2004, and the magnitude range of target events 8.0 ≤ M < 8.5 are considered as basic to this M8 analysis. We find the point and upper estimates of α and show that they are still unstable because the number of target events in the experiment is small. However, our results argue in favour of non-triviality of the M8 prediction algorithm. (author)
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The limits of earthquake early warning: Timeliness of ground motion estimates
Minson, Sarah E.; Meier, Men-Andrin; Baltay, Annemarie S.; Hanks, Thomas C.; Cochran, Elizabeth S.
2018-01-01
The basic physics of earthquakes is such that strong ground motion cannot be expected from an earthquake unless the earthquake itself is very close or has grown to be very large. We use simple seismological relationships to calculate the minimum time that must elapse before such ground motion can be expected at a distance from the earthquake, assuming that the earthquake magnitude is not predictable. Earthquake early warning (EEW) systems are in operation or development for many regions aroun...
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International Nuclear Information System (INIS)
Collin, Blaise P.; Petti, David A.; Demkowicz, Paul A.; Maki, John T.
2014-01-01
The PARFUME (PARticle FUel ModEl) code was used to predict fission product release from tristructural isotropic (TRISO) coated fuel particles and compacts during the first irradiation experiment (AGR-1) of the Advanced Gas Reactor Fuel Development and Qualification program. The PARFUME model for the AGR-1 experiment used the fuel compact volume average temperature for each of the 620 days of irradiation to calculate the release of fission products silver, cesium, and strontium from a representative particle for a select number of AGR-1 compacts. Post-irradiation examination (PIE) measurements provided data on release of fission products from fuel compacts and fuel particles, and retention of fission products in the compacts outside of the silicon carbide (SiC) layer. PARFUME-predicted fractional release of these fission products was determined and compared to the PIE measurements. Results show an overall over-prediction of the fractional release of cesium by PARFUME. For particles with failed SiC layers, the over-prediction is by a factor of about two, corresponding to an over-estimation of the diffusivity in uranium oxycarbide (UCO) by a factor of about 100. For intact particles, whose release is much lower, the over-prediction is by an average of about an order of magnitude, which could additionally be attributed to an over-estimated diffusivity in SiC by about 30%. The release of strontium from intact particles is also over-estimated by PARFUME, which also points towards an over-estimated diffusivity of strontium in either SiC or UCO, or possibly both. The measured strontium fractional release from intact particles varied considerably from compact to compact, making it difficult to assess the effective over-estimation of the diffusivities. Furthermore, the release of strontium from particles with failed SiC is difficult to observe experimentally due to the release from intact particles, preventing any conclusions to be made on the accuracy or validity of the
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Finite element simulation of earthquake cycle dynamics for continental listric fault system
Wei, T.; Shen, Z. K.
2017-12-01
We simulate stress/strain evolution through earthquake cycles for a continental listric fault system using the finite element method. A 2-D lithosphere model is developed, with the upper crust composed of plasto-elastic materials and the lower crust/upper mantle composed of visco-elastic materials respectively. The media is sliced by a listric fault, which is soled into the visco-elastic lower crust at its downdip end. The system is driven laterally by constant tectonic loading. Slip on fault is controlled by rate-state friction. We start with a simple static/dynamic friction law, and drive the system through multiple earthquake cycles. Our preliminary results show that: (a) periodicity of the earthquake cycles is strongly modulated by the static/dynamic friction, with longer period correlated with higher static friction and lower dynamic friction; (b) periodicity of earthquake is a function of fault depth, with less frequent events of greater magnitudes occurring at shallower depth; and (c) rupture on fault cannot release all the tectonic stress in the system, residual stress is accumulated in the hanging wall block at shallow depth close to the fault, which has to be released either by conjugate faulting or inelastic folding. We are in a process of exploring different rheologic structure and friction laws and examining their effects on earthquake behavior and deformation pattern. The results will be applied to specific earthquakes and fault zones such as the 2008 great Wenchuan earthquake on the Longmen Shan fault system.
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Experimental study of structural response to earthquakes
International Nuclear Information System (INIS)
Clough, R.W.; Bertero, V.V.; Bouwkamp, J.G.; Popov, E.P.
1975-01-01
The objectives, methods, and some of the principal results obtained from experimental studies of the behavior of structures subjected to earthquakes are described. Although such investigations are being conducted in many laboratories throughout the world, the information presented deals specifically with projects being carried out at the Earthquake Engineering Research Center (EERC) of the University of California, Berkeley. A primary purpose of these investigations is to obtain detailed information on the inelastic response mechanisms in typical structural systems so that the experimentally observed performance can be compared with computer generated analytical predictions. Only by such comparisons can the mathematical models used in dynamic nonlinear analyses be verified and improved. Two experimental procedures for investigating earthquake structural response are discussed: the earthquake simulator facility which subjects the base of the test structure to acceleration histories similar to those recorded in actual earthquakes, and systems of hydraulic rams which impose specified displacement histories on the test components, equivalent to motions developed in structures subjected to actual'quakes. The general concept and performance of the 20ft square EERC earthquake simulator is described, and the testing of a two story concrete frame building is outlined. Correlation of the experimental results with analytical predictions demonstrates that satisfactory agreement can be obtained only if the mathematical model incorporates a stiffness deterioration mechanism which simulates the cracking and other damage suffered by the structure
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Jaiswal, Kishor; Wald, David J.; Earle, Paul S.; Porter, Keith A.; Hearne, Mike
2011-01-01
Since the launch of the USGS’s Prompt Assessment of Global Earthquakes for Response (PAGER) system in fall of 2007, the time needed for the U.S. Geological Survey (USGS) to determine and comprehend the scope of any major earthquake disaster anywhere in the world has been dramatically reduced to less than 30 min. PAGER alerts consist of estimated shaking hazard from the ShakeMap system, estimates of population exposure at various shaking intensities, and a list of the most severely shaken cities in the epicentral area. These estimates help government, scientific, and relief agencies to guide their responses in the immediate aftermath of a significant earthquake. To account for wide variability and uncertainty associated with inventory, structural vulnerability and casualty data, PAGER employs three different global earthquake fatality/loss computation models. This article describes the development of the models and demonstrates the loss estimation capability for earthquakes that have occurred since 2007. The empirical model relies on country-specific earthquake loss data from past earthquakes and makes use of calibrated casualty rates for future prediction. The semi-empirical and analytical models are engineering-based and rely on complex datasets including building inventories, time-dependent population distributions within different occupancies, the vulnerability of regional building stocks, and casualty rates given structural collapse.
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Hreinsdottir, Sigrun
2005-07-01
GPS geodetic measurements are used to study two major earthquakes, the 2001 MW 7.7 El Salvador and 2002 MW 7.9 Denali Fault earthquakes. The 2001 MW 7.7 earthquake was a normal fault event in the subducting Cocos plate offshore El Salvador. Coseismic displacements of up to 15 mm were measured at permanent GPS stations in Central America. The GPS data were used to constrain the location of and slip on the normal fault. One month later a MW 6.6 strike-slip earthquake occurred in the overriding Caribbean plate. Coulomb stress changes estimated from the M W 7.7 earthquake suggest that it triggered the MW 6.6 earthquake. Coseismic displacement from the MW 6.6 earthquake, about 40 mm at a GPS station in El Salvador, indicates that the earthquake triggered additional slip on a fault close to the GPS station. The MW 6.6 earthquake further changed the stress field in the overriding Caribbean plate, with triggered seismic activity occurring west and possibly also to the east of the rupture in the days to months following the earthquake. The MW 7.9 Denali Fault earthquake ruptured three faults in the interior of Alaska. It initiated with a thrust motion on the Susitna Glacier fault but then ruptured the Denali and Totschunda faults with predominantly right-lateral strike-slip motion unilaterally from west to east. GPS data measured in the two weeks following the earthquake suggest a complex coseismic rupture along the faults with two main regions of moment release along the Denali fault. A large amount of additional data were collected in the year following the earthquake which greatly improved the resolution on the fault, revealing more details of the slip distribution. We estimate a total moment release of 6.81 x 1020 Nm in the earthquake with a M W 7.2 thrust subevent on Susitna Glacier fault. The slip on the Denali fault is highly variable, with 4 main pulses of moment release. The largest moment pulse corresponds to a MW 7.5 subevent, about 40 km west of the Denali
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Lee, Shiann-Jong; Liu, Qinya; Tromp, Jeroen; Komatitsch, Dimitri; Liang, Wen-Tzong; Huang, Bor-Shouh
2014-06-01
We developed a Real-time Online earthquake Simulation system (ROS) to simulate regional earthquakes in Taiwan. The ROS uses a centroid moment tensor solution of seismic events from a Real-time Moment Tensor monitoring system (RMT), which provides all the point source parameters including the event origin time, hypocentral location, moment magnitude and focal mechanism within 2 min after the occurrence of an earthquake. Then, all of the source parameters are automatically forwarded to the ROS to perform an earthquake simulation, which is based on a spectral-element method (SEM). A new island-wide, high resolution SEM mesh model is developed for the whole Taiwan in this study. We have improved SEM mesh quality by introducing a thin high-resolution mesh layer near the surface to accommodate steep and rapidly varying topography. The mesh for the shallow sedimentary basin is adjusted to reflect its complex geometry and sharp lateral velocity contrasts. The grid resolution at the surface is about 545 m, which is sufficient to resolve topography and tomography data for simulations accurate up to 1.0 Hz. The ROS is also an infrastructural service, making online earthquake simulation feasible. Users can conduct their own earthquake simulation by providing a set of source parameters through the ROS webpage. For visualization, a ShakeMovie and ShakeMap are produced during the simulation. The time needed for one event is roughly 3 min for a 70 s ground motion simulation. The ROS is operated online at the Institute of Earth Sciences, Academia Sinica (http://ros.earth.sinica.edu.tw/). Our long-term goal for the ROS system is to contribute to public earth science outreach and to realize seismic ground motion prediction in real-time.
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International Nuclear Information System (INIS)
Mishima, J.; Ayer, J.E.
1981-11-01
The potential airborne releases of radionuclides (source terms) that could result from wind and earthquake dmage are estimated for the Battelle Memorial Institute Columbus Laboratories JN-1b Building at the West Jefferson site in Ohio. The estimated source terms are based on the damage to barriers containing the radionuclides, the inventory of radionuclides at risk, and the fraction of the inventory made airborne as a result of the loss of containment. In an attempt to provide a realistic range of potential source terms that include most of the normal operating conditions, a best estimate bounded by upper and lower limits is calculated by combining the upper-bound, best-estimate, and lower-bound inventories-at-risk with an airborne release factor (upper-bound, best-estimate, and lower-bound if possible) for the situation. The factors used to evaluate the fractional airborne release of materials and the exchange rates between enclosed and exterior atmospheres are discussed. The postulated damage and source terms are discussed for wind and earthquake hazard scenarios in order of their increasing severity
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Connecting slow earthquakes to huge earthquakes.
Obara, Kazushige; Kato, Aitaro
2016-07-15
Slow earthquakes are characterized by a wide spectrum of fault slip behaviors and seismic radiation patterns that differ from those of traditional earthquakes. However, slow earthquakes and huge megathrust earthquakes can have common slip mechanisms and are located in neighboring regions of the seismogenic zone. The frequent occurrence of slow earthquakes may help to reveal the physics underlying megathrust events as useful analogs. Slow earthquakes may function as stress meters because of their high sensitivity to stress changes in the seismogenic zone. Episodic stress transfer to megathrust source faults leads to an increased probability of triggering huge earthquakes if the adjacent locked region is critically loaded. Careful and precise monitoring of slow earthquakes may provide new information on the likelihood of impending huge earthquakes. Copyright © 2016, American Association for the Advancement of Science.
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Parallelization of the Coupled Earthquake Model
Block, Gary; Li, P. Peggy; Song, Yuhe T.
2007-01-01
This Web-based tsunami simulation system allows users to remotely run a model on JPL s supercomputers for a given undersea earthquake. At the time of this reporting, predicting tsunamis on the Internet has never happened before. This new code directly couples the earthquake model and the ocean model on parallel computers and improves simulation speed. Seismometers can only detect information from earthquakes; they cannot detect whether or not a tsunami may occur as a result of the earthquake. When earthquake-tsunami models are coupled with the improved computational speed of modern, high-performance computers and constrained by remotely sensed data, they are able to provide early warnings for those coastal regions at risk. The software is capable of testing NASA s satellite observations of tsunamis. It has been successfully tested for several historical tsunamis, has passed all alpha and beta testing, and is well documented for users.
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Bend Faulting at the Edge of a Flat Slab: The 2017 Mw7.1 Puebla-Morelos, Mexico Earthquake
Melgar, Diego; Pérez-Campos, Xyoli; Ramirez-Guzman, Leonardo; Spica, Zack; Espíndola, Victor Hugo; Hammond, William C.; Cabral-Cano, Enrique
2018-03-01
We present results of a slip model from joint inversion of strong motion and static Global Positioning System data for the Mw7.1 Puebla-Morelos earthquake. We find that the earthquake nucleates at the bottom of the oceanic crust or within the oceanic mantle with most of the moment release occurring within the oceanic mantle. Given its location at the edge of the flat slab, the earthquake is likely the result of bending stresses occurring at the transition from flat slab subduction to steeply dipping subduction. The event strikes obliquely to the slab, we find a good agreement between the seafloor fabric offshore the source region and the strike of the earthquake. We argue that the event likely reactivated a fault first created during seafloor formation. We hypothesize that large bending-related events at the edge of the flat slab are more likely in areas of low misalignment between the seafloor fabric and the slab strike where reactivation of preexisting structures is favored. This hypothesis predicts decreased likelihood of bending-related events northwest of the 2017 source region but also suggests that they should be more likely southeast of the 2017 source region.
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Energy Technology Data Exchange (ETDEWEB)
Collin, Blaise P.; Demkowicz, Paul A.; Baldwin, Charles A.; Harp, Jason M.; Hunn, John D.
2016-11-01
The PARFUME (PARticle FUel ModEl) code was used to predict silver release from tristructural isotropic (TRISO) coated fuel particles and compacts during the second irradiation experiment (AGR-2) of the Advanced Gas Reactor Fuel Development and Qualification program. The PARFUME model for the AGR-2 experiment used the fuel compact volume average temperature for each of the 559 days of irradiation to calculate the release of fission product silver from a representative particle for a select number of AGR-2 compacts and individual fuel particles containing either mixed uranium carbide/oxide (UCO) or 100% uranium dioxide (UO2) kernels. Post-irradiation examination (PIE) measurements were performed to provide data on release of silver from these compacts and individual fuel particles. The available experimental fractional releases of silver were compared to their corresponding PARFUME predictions. Preliminary comparisons show that PARFUME under-predicts the PIE results in UCO compacts and is in reasonable agreement with experimental data for UO2 compacts. The accuracy of PARFUME predictions is impacted by the code limitations in the modeling of the temporal and spatial distributions of the temperature across the compacts. Nevertheless, the comparisons on silver release lie within the same order of magnitude.
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Seismic-electromagnetic precursors of Romania's Vrancea earthquakes
International Nuclear Information System (INIS)
Enescu, B.D.; Enescu, C.; Constantin, A. P.
1999-01-01
Diagrams were plotted from electromagnetic data that were recorded at Muntele Rosu Observatory during December 1996 to January 1997, and December 1997 to September 1998. The times when Vrancea earthquakes of magnitudes M ≥ 3.9 occurred within these periods are marked on the diagrams.The parameters of the earthquakes are given in a table which also includes information on the magnetic and electric anomalies (perturbations) preceding these earthquakes. The magnetic data prove that Vrancea earthquakes are preceded by magnetic perturbations that may be regarded as their short-term precursors. Perturbations, which could likewise be seen as short-term precursors of Vrancea earthquakes, are also noticed in the electric records. Still, a number of electric data do cast a doubt on their forerunning nature. Some suggestions are made in the end of the paper on how electromagnetic research should go ahead to be of use for Vrancea earthquake prediction. (authors)
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Parallel Earthquake Simulations on Large-Scale Multicore Supercomputers
Wu, Xingfu
2011-01-01
Earthquakes are one of the most destructive natural hazards on our planet Earth. Hugh earthquakes striking offshore may cause devastating tsunamis, as evidenced by the 11 March 2011 Japan (moment magnitude Mw9.0) and the 26 December 2004 Sumatra (Mw9.1) earthquakes. Earthquake prediction (in terms of the precise time, place, and magnitude of a coming earthquake) is arguably unfeasible in the foreseeable future. To mitigate seismic hazards from future earthquakes in earthquake-prone areas, such as California and Japan, scientists have been using numerical simulations to study earthquake rupture propagation along faults and seismic wave propagation in the surrounding media on ever-advancing modern computers over past several decades. In particular, ground motion simulations for past and future (possible) significant earthquakes have been performed to understand factors that affect ground shaking in populated areas, and to provide ground shaking characteristics and synthetic seismograms for emergency preparation and design of earthquake-resistant structures. These simulation results can guide the development of more rational seismic provisions for leading to safer, more efficient, and economical50pt]Please provide V. Taylor author e-mail ID. structures in earthquake-prone regions.
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The origin of high frequency radiation in earthquakes and the geometry of faulting
Madariaga, R.
2004-12-01
In a seminal paper of 1967 Kei Aki discovered the scaling law of earthquake spectra and showed that, among other things, the high frequency decay was of type omega-squared. This implies that high frequency displacement amplitudes are proportional to a characteristic length of the fault, and radiated energy scales with the cube of the fault dimension, just like seismic moment. Later in the seventies, it was found out that a simple explanation for this frequency dependence of spectra was that high frequencies were generated by stopping phases, waves emitted by changes in speed of the rupture front as it propagates along the fault, but this did not explain the scaling of high frequency waves with fault length. Earthquake energy balance is such that, ignoring attenuation, radiated energy is the change in strain energy minus energy released for overcoming friction. Until recently the latter was considered to be a material property that did not scale with fault size. Yet, in another classical paper Aki and Das estimated in the late 70s that energy release rate also scaled with earthquake size, because earthquakes were often stopped by barriers or changed rupture speed at them. This observation was independently confirmed in the late 90s by Ide and Takeo and Olsen et al who found that energy release rates for Kobe and Landers were in the order of a MJ/m2, implying that Gc necessarily scales with earthquake size, because if this was a material property, small earthquakes would never occur. Using both simple analytical and numerical models developed by Addia-Bedia and Aochi and Madariaga, we examine the consequence of these observations for the scaling of high frequency waves with fault size. We demonstrate using some classical results by Kostrov, Husseiny and Freund that high frequency energy flow measures energy release rate and is generated when ruptures change velocity (both direction and speed) at fault kinks or jogs. Our results explain why super shear ruptures are
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Borcherdt, Roger D.
2014-01-01
Proposals are developed to update Tables 11.4-1 and 11.4-2 of Minimum Design Loads for Buildings and Other Structures published as American Society of Civil Engineers Structural Engineering Institute standard 7-10 (ASCE/SEI 7–10). The updates are mean next generation attenuation (NGA) site coefficients inferred directly from the four NGA ground motion prediction equations used to derive the maximum considered earthquake response maps adopted in ASCE/SEI 7–10. Proposals include the recommendation to use straight-line interpolation to infer site coefficients at intermediate values of (average shear velocity to 30-m depth). The NGA coefficients are shown to agree well with adopted site coefficients at low levels of input motion (0.1 g) and those observed from the Loma Prieta earthquake. For higher levels of input motion, the majority of the adopted values are within the 95% epistemic-uncertainty limits implied by the NGA estimates with the exceptions being the mid-period site coefficient, Fv, for site class D and the short-period coefficient, Fa, for site class C, both of which are slightly less than the corresponding 95% limit. The NGA data base shows that the median value of 913 m/s for site class B is more typical than 760 m/s as a value to characterize firm to hard rock sites as the uniform ground condition for future maximum considered earthquake response ground motion estimates. Future updates of NGA ground motion prediction equations can be incorporated easily into future adjustments of adopted site coefficients using procedures presented herein.
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Connecting slow earthquakes to huge earthquakes
Obara, Kazushige; Kato, Aitaro
2016-01-01
Slow earthquakes are characterized by a wide spectrum of fault slip behaviors and seismic radiation patterns that differ from those of traditional earthquakes. However, slow earthquakes and huge megathrust earthquakes can have common slip mechanisms and are located in neighboring regions of the seismogenic zone. The frequent occurrence of slow earthquakes may help to reveal the physics underlying megathrust events as useful analogs. Slow earthquakes may function as stress meters because of th...
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Earthquake in Japan: The IAEA mission gives its report
International Nuclear Information System (INIS)
Anon.
2007-01-01
Following the seism that occurred on the 16. july 2007 in Japan (magnitude 6.6 on Richter scale), an IAEA mission has inspected the nuclear power plant of Kashiwazaki Kariwa at the beginning of August. The mission has estimated that the safety of the installation has been provided during and after the earthquake, in spite of the fact that the earthquake has gone past the seism level taken as reference in the conception of the nuclear facility. The systems and the components were in a better state that it could be imagined after a such earthquake. The release have been under the authorised thresholds. At the moment of the seism, three reactors were running on the seven ones of the nuclear power plant, and stopped automatically. The unit 2 that started up, has also stopped automatically. The reactors 1, 5 and 6 were stopped for maintenance. Water poured out coming from the spent fuel storage pool because of the earth tremors. It was picked and thrown out by the release pipe to the sea without notable impact on environment ( volume 1.2 m 3 ). One hundred of containers was overturned. Traces of iodine, chromium 51 and cobalt 60 have been found in the ventilation filters ( reactor 7) these elements have been released in atmosphere in very low quantities. (N.C.)
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Assigning probability gain for precursors of four large Chinese earthquakes
Energy Technology Data Exchange (ETDEWEB)
Cao, T.; Aki, K.
1983-03-10
We extend the concept of probability gain associated with a precursor (Aki, 1981) to a set of precursors which may be mutually dependent. Making use of a new formula, we derive a criterion for selecting precursors from a given data set in order to calculate the probability gain. The probabilities per unit time immediately before four large Chinese earthquakes are calculated. They are approximately 0.09, 0.09, 0.07 and 0.08 per day for 1975 Haicheng (M = 7.3), 1976 Tangshan (M = 7.8), 1976 Longling (M = 7.6), and Songpan (M = 7.2) earthquakes, respectively. These results are encouraging because they suggest that the investigated precursory phenomena may have included the complete information for earthquake prediction, at least for the above earthquakes. With this method, the step-by-step approach to prediction used in China may be quantified in terms of the probability of earthquake occurrence. The ln P versus t curve (where P is the probability of earthquake occurrence at time t) shows that ln P does not increase with t linearly but more rapidly as the time of earthquake approaches.
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Earthquake Energy Distribution along the Earth Surface and Radius
International Nuclear Information System (INIS)
Varga, P.; Krumm, F.; Riguzzi, F.; Doglioni, C.; Suele, B.; Wang, K.; Panza, G.F.
2010-07-01
The global earthquake catalog of seismic events with M W ≥ 7.0, for the time interval from 1950 to 2007, shows that the depth distribution of earthquake energy release is not uniform. The 90% of the total earthquake energy budget is dissipated in the first ∼30km, whereas most of the residual budget is radiated at the lower boundary of the transition zone (410 km - 660 km), above the upper-lower mantle boundary. The upper border of the transition zone at around 410 km of depth is not marked by significant seismic energy release. This points for a non-dominant role of the slabs in the energy budged of plate tectonics. Earthquake number and energy release, although not well correlated, when analysed with respect to the latitude, show a decrease toward the polar areas. Moreover, the radiated energy has the highest peak close to (±5 o ) the so-called tectonic equator defined by Crespi et al. (2007), which is inclined about 30 o with respect to the geographic equator. At the same time the presence of a clear axial co- ordination of the radiated seismic energy is demonstrated with maxima at latitudes close to critical (±45 o ). This speaks about the presence of external forces that influence seismicity and it is consistent with the fact that Gutenberg-Richter law is linear, for events with M>5, only when the whole Earth's seismicity is considered. These data are consistent with an astronomical control on plate tectonics, i.e., the despinning (slowing of the Earth's angular rotation) of the Earth's rotation caused primarily by the tidal friction due to the Moon. The mutual position of the shallow and ∼660 km deep earthquake energy sources along subduction zones allows us to conclude that they are connected with the same slab along the W-directed subduction zones, but they may rather be disconnected along the opposed E-NE-directed slabs, being the deep seismicity controlled by other mechanisms. (author)
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Injection-induced moment release can also be aseismic
McGarr, Arthur; Barbour, Andrew J.
2018-01-01
The cumulative seismic moment is a robust measure of the earthquake response to fluid injection for injection volumes ranging from 3100 to about 12 million m3. Over this range, the moment release is limited to twice the product of the shear modulus and the volume of injected fluid. This relation also applies at the much smaller injection volumes of the field experiment in France reported by Guglielmi, et al. (2015) and laboratory experiments to simulate hydraulic fracturing described by Goodfellow, et al. (2015). In both of these studies, the relevant moment release for comparison with the fluid injection was aseismic and consistent with the scaling that applies to the much larger volumes associated with injection-induced earthquakes with magnitudes extending up to 5.8. Neither the micro-earthquakes, at the site in France, nor the acoustic emission in the laboratory samples contributed significantly to the deformation due to fluid injection.
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Cooperative earthquake research between the United States and the People's Republic of China
Energy Technology Data Exchange (ETDEWEB)
Russ, D.P.; Johnson, L.E.
1986-01-01
This paper describes cooperative research by scientists of the US and the People's Republic of China (PRC) which has resulted in important new findings concerning the fundamental characteristics of earthquakes and new insight into mitigating earthquake hazards. There have been over 35 projects cooperatively sponsored by the Earthquake Studies Protocol in the past 5 years. The projects are organized into seven annexes, including investigations in earthquake prediction, intraplate faults and earthquakes, earthquake engineering and hazards investigation, deep crustal structure, rock mechanics, seismology, and data exchange. Operational earthquake prediction experiments are currently being developed at two primary sites: western Yunnan Province near the town of Xiaguan, where there are several active faults, and the northeast China plain, where the devastating 1976 Tangshan earthquake occurred.
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Ionospheric precursors for crustal earthquakes in Italy
Directory of Open Access Journals (Sweden)
L. Perrone
2010-04-01
Full Text Available Crustal earthquakes with magnitude 6.0>M≥5.5 observed in Italy for the period 1979–2009 including the last one at L'Aquila on 6 April 2009 were considered to check if the earlier obtained relationships for ionospheric precursors for strong Japanese earthquakes are valid for the Italian moderate earthquakes. The ionospheric precursors are based on the observed variations of the sporadic E-layer parameters (h'Es, fbEs and foF2 at the ionospheric station Rome. Empirical dependencies for the seismo-ionospheric disturbances relating the earthquake magnitude and the epicenter distance are obtained and they have been shown to be similar to those obtained earlier for Japanese earthquakes. The dependences indicate the process of spreading the disturbance from the epicenter towards periphery during the earthquake preparation process. Large lead times for the precursor occurrence (up to 34 days for M=5.8–5.9 tells about a prolong preparation period. A possibility of using the obtained relationships for the earthquakes prediction is discussed.
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Geological and historical evidence of irregular recurrent earthquakes in Japan.
Satake, Kenji
2015-10-28
Great (M∼8) earthquakes repeatedly occur along the subduction zones around Japan and cause fault slip of a few to several metres releasing strains accumulated from decades to centuries of plate motions. Assuming a simple 'characteristic earthquake' model that similar earthquakes repeat at regular intervals, probabilities of future earthquake occurrence have been calculated by a government committee. However, recent studies on past earthquakes including geological traces from giant (M∼9) earthquakes indicate a variety of size and recurrence interval of interplate earthquakes. Along the Kuril Trench off Hokkaido, limited historical records indicate that average recurrence interval of great earthquakes is approximately 100 years, but the tsunami deposits show that giant earthquakes occurred at a much longer interval of approximately 400 years. Along the Japan Trench off northern Honshu, recurrence of giant earthquakes similar to the 2011 Tohoku earthquake with an interval of approximately 600 years is inferred from historical records and tsunami deposits. Along the Sagami Trough near Tokyo, two types of Kanto earthquakes with recurrence interval of a few hundred years and a few thousand years had been recognized, but studies show that the recent three Kanto earthquakes had different source extents. Along the Nankai Trough off western Japan, recurrence of great earthquakes with an interval of approximately 100 years has been identified from historical literature, but tsunami deposits indicate that the sizes of the recurrent earthquakes are variable. Such variability makes it difficult to apply a simple 'characteristic earthquake' model for the long-term forecast, and several attempts such as use of geological data for the evaluation of future earthquake probabilities or the estimation of maximum earthquake size in each subduction zone are being conducted by government committees. © 2015 The Author(s).
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Cadmium release from a reprocessing electrorefiner falling over
Energy Technology Data Exchange (ETDEWEB)
Solbrig, Charles W., E-mail: Charles.solbrig@inl.gov [Batelle Energy Alliance, Idaho National Laboratory, PO Box 2528, Idaho Falls, ID 83404 (United States); Pope, Chad L. [Batelle Energy Alliance, Idaho National Laboratory, PO Box 2528, Idaho Falls, ID 83404 (United States)
2013-02-15
Highlights: ► We model an accident in a nuclear fuel processing facility caused by an earthquake. ► The earthquake causes the argon cell to breach and the electrorefiner to tip over. ► Cadmium is spilled and a cathode falls on the cadmium and starts to burn. ► Cadmium can be transported to people in the building, the site, and the public. ► The results show negligible doses to all persons except in one low probability case. -- Abstract: The possible biological consequences of a release of cadmium due to a design basis earthquake in the Idaho Nuclear Laboratory's nuclear fuel reprocessing cell are evaluated. The facility is designed to withstand the design basis earthquake except for some non-seismically qualified feedthroughs. The earthquake is hypothesized to breach these feedthroughs (allowing air into the argon atmosphere processing cell) and cause the MK-IV electrorefiner (ER) in the cell to tip over or split and spill its contents of fission product laden salt and cadmium. In addition, the uranium dendrite product cathode is assumed to fall on the cadmium and burn. The heat from the burning cathode results in release of cadmium vapor into the cell atmosphere. Ingestion and inhalation of a sufficient concentration of cadmium for a critical time period can cause irreversible health effects or death. The release of the small quantity of fission products, analyzed elsewhere, results in negligible doses. Analysis reported here shows there is no danger to the general public by the cadmium release or to on-site workers except in one low probability case. This one case requires a fivefold failure where the safety exhaust system fails just after the 4% oxygen concentration combustion limit in the cell is reached. Failure of the SES allows oscillatory inflow and outflow (and hence cadmium outflow) from the cell due to gravity. The dose to a worker in the basement exceeds the mortality limit in this one event if the worker does not leave the basement.
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Cadmium release from a reprocessing electrorefiner falling over
International Nuclear Information System (INIS)
Solbrig, Charles W.; Pope, Chad L.
2013-01-01
Highlights: ► We model an accident in a nuclear fuel processing facility caused by an earthquake. ► The earthquake causes the argon cell to breach and the electrorefiner to tip over. ► Cadmium is spilled and a cathode falls on the cadmium and starts to burn. ► Cadmium can be transported to people in the building, the site, and the public. ► The results show negligible doses to all persons except in one low probability case. -- Abstract: The possible biological consequences of a release of cadmium due to a design basis earthquake in the Idaho Nuclear Laboratory's nuclear fuel reprocessing cell are evaluated. The facility is designed to withstand the design basis earthquake except for some non-seismically qualified feedthroughs. The earthquake is hypothesized to breach these feedthroughs (allowing air into the argon atmosphere processing cell) and cause the MK-IV electrorefiner (ER) in the cell to tip over or split and spill its contents of fission product laden salt and cadmium. In addition, the uranium dendrite product cathode is assumed to fall on the cadmium and burn. The heat from the burning cathode results in release of cadmium vapor into the cell atmosphere. Ingestion and inhalation of a sufficient concentration of cadmium for a critical time period can cause irreversible health effects or death. The release of the small quantity of fission products, analyzed elsewhere, results in negligible doses. Analysis reported here shows there is no danger to the general public by the cadmium release or to on-site workers except in one low probability case. This one case requires a fivefold failure where the safety exhaust system fails just after the 4% oxygen concentration combustion limit in the cell is reached. Failure of the SES allows oscillatory inflow and outflow (and hence cadmium outflow) from the cell due to gravity. The dose to a worker in the basement exceeds the mortality limit in this one event if the worker does not leave the basement
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International Nuclear Information System (INIS)
Esmer, Oezcan
2006-01-01
This paper first evaluates the earthquake prediction method (1999 ) used by US Geological Survey as the lead example and reviews also the recent models. Secondly, points out the ongoing debate on the predictability of earthquake recurrences and lists the main claims of both sides. The traditional methods and the 'frequentist' approach used in determining the earthquake probabilities cannot end the complaints that the earthquakes are unpredictable. It is argued that the prevailing 'crisis' in seismic research corresponds to the Pre-Maxent Age of the current situation. The period of Kuhnian 'Crisis' should give rise to a new paradigm based on the Information-Theoric framework including the inverse problem, Maxent and Bayesian methods. Paper aims to show that the information- theoric methods shall provide the required 'Methodica Firma' for the earthquake prediction models
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Seismic dynamics in advance and after the recent strong earthquakes in Italy and New Zealand
Nekrasova, A.; Kossobokov, V. G.
2017-12-01
We consider seismic events as a sequence of avalanches in self-organized system of blocks-and-faults of the Earth lithosphere and characterize earthquake series with the distribution of the control parameter, η = τ × 10B × (5-M) × L C of the Unified Scaling Law for Earthquakes, USLE (where τ is inter-event time, B is analogous to the Gutenberg-Richter b-value, and C is fractal dimension of seismic locus). A systematic analysis of earthquake series in Central Italy and New Zealand, 1993-2017, suggests the existence, in a long-term, of different rather steady levels of seismic activity characterized with near constant values of η, which, in mid-term, intermittently switch at times of transitions associated with the strong catastrophic events. On such a transition, seismic activity, in short-term, may follow different scenarios with inter-event time scaling of different kind, including constant, logarithmic, power law, exponential rise/decay or a mixture of those. The results do not support the presence of universality in seismic energy release. The observed variability of seismic activity in advance and after strong (M6.0+) earthquakes in Italy and significant (M7.0+) earthquakes in New Zealand provides important constraints on modelling realistic earthquake sequences by geophysicists and can be used to improve local seismic hazard assessments including earthquake forecast/prediction methodologies. The transitions of seismic regime in Central Italy and New Zealand started in 2016 are still in progress and require special attention and geotechnical monitoring. It would be premature to make any kind of definitive conclusions on the level of seismic hazard which is evidently high at this particular moment of time in both regions. The study supported by the Russian Science Foundation Grant No.16-17-00093.
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Campbell, M. R.; Salditch, L.; Brooks, E. M.; Stein, S.; Spencer, B. D.
2017-12-01
getting a hit is N%" or "the probability of an earthquake is N%" involves specifying the assumptions made. Different plausible assumptions yield a wide range of estimates. In both seismology and sports, how to better predict future performance remains an important question.
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Goda, Katsuichiro; Mai, Paul Martin; Yasuda, Tomohiro; Mori, Nobuhito
2014-01-01
In this study, we develop stochastic random-field slip models for the 2011 Tohoku earthquake and conduct a rigorous sensitivity analysis of tsunami hazards with respect to the uncertainty of earthquake slip and fault geometry. Synthetic earthquake slip distributions generated from the modified Mai-Beroza method captured key features of inversion-based source representations of the mega-thrust event, which were calibrated against rich geophysical observations of this event. Using original and synthesised earthquake source models (varied for strike, dip, and slip distributions), tsunami simulations were carried out and the resulting variability in tsunami hazard estimates was investigated. The results highlight significant sensitivity of the tsunami wave profiles and inundation heights to the coastal location and the slip characteristics, and indicate that earthquake slip characteristics are a major source of uncertainty in predicting tsunami risks due to future mega-thrust events.
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Goda, Katsuichiro
2014-09-01
In this study, we develop stochastic random-field slip models for the 2011 Tohoku earthquake and conduct a rigorous sensitivity analysis of tsunami hazards with respect to the uncertainty of earthquake slip and fault geometry. Synthetic earthquake slip distributions generated from the modified Mai-Beroza method captured key features of inversion-based source representations of the mega-thrust event, which were calibrated against rich geophysical observations of this event. Using original and synthesised earthquake source models (varied for strike, dip, and slip distributions), tsunami simulations were carried out and the resulting variability in tsunami hazard estimates was investigated. The results highlight significant sensitivity of the tsunami wave profiles and inundation heights to the coastal location and the slip characteristics, and indicate that earthquake slip characteristics are a major source of uncertainty in predicting tsunami risks due to future mega-thrust events.
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Hazard Forecasting by MRI: A Prediction Algorithm of the First Kind
Lomnitz, C.
2003-12-01
Seismic gaps do not tell us when and where the next earthquake is due. We present new results on limited earthquake hazard prediction at plate boundaries. Our algorithm quantifies earthquake hazard in seismic gaps. The prediction window found for M7 is on the order of 50 km by 20 years (Lomnitz, 1996a). The earth is unstable with respect to small perturbations of the initial conditions. A prediction of the first kind is an estimate of the time evolution of a complex system with fixed boundary conditions in response to changes in the initial state, for example, weather prediction (Edward Lorenz, 1975; Hasselmann, 2002). We use the catalog of large world earthquakes as a proxy for the initial conditions. The MRI algorithm simulates the response of the system to updating the catalog. After a local stress transient dP the entropy decays as (grad dP)2 due to transient flows directed toward the epicenter. Healing is the thermodynamic process which resets the state of stress. It proceeds as a power law from the rupture boundary inwards, as in a wound. The half-life of a rupture is defined as the healing time which shrinks the size of a scar by half. Healed segments of plate boundary can rupture again. From observations in Chile, Mexico and Japan we find that the half-life of a seismic rupture is about 20 years, in agreement with seismic gap observations. The moment ratio MR is defined as the contrast between the cumulative regional moment release and the local moment deficiency at time t along the plate boundary. The procedure is called MRI. The findings: (1) MRI works; (2) major earthquakes match prominent peaks in the MRI graph; (3) important events (Central Chile 1985; Mexico 1985; Kobe 1995) match MRI peaks which began to emerge 10 to 20 years before the earthquake; (4) The emergence of peaks in MRI depends on earlier ruptures that occurred, not adjacent to but at 10 to 20 fault lengths from the epicentral region, in agreement with triggering effects. The hazard
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The HayWired Earthquake Scenario—Earthquake Hazards
Detweiler, Shane T.; Wein, Anne M.
2017-04-24
The HayWired scenario is a hypothetical earthquake sequence that is being used to better understand hazards for the San Francisco Bay region during and after an earthquake of magnitude 7 on the Hayward Fault. The 2014 Working Group on California Earthquake Probabilities calculated that there is a 33-percent likelihood of a large (magnitude 6.7 or greater) earthquake occurring on the Hayward Fault within three decades. A large Hayward Fault earthquake will produce strong ground shaking, permanent displacement of the Earth’s surface, landslides, liquefaction (soils becoming liquid-like during shaking), and subsequent fault slip, known as afterslip, and earthquakes, known as aftershocks. The most recent large earthquake on the Hayward Fault occurred on October 21, 1868, and it ruptured the southern part of the fault. The 1868 magnitude-6.8 earthquake occurred when the San Francisco Bay region had far fewer people, buildings, and infrastructure (roads, communication lines, and utilities) than it does today, yet the strong ground shaking from the earthquake still caused significant building damage and loss of life. The next large Hayward Fault earthquake is anticipated to affect thousands of structures and disrupt the lives of millions of people. Earthquake risk in the San Francisco Bay region has been greatly reduced as a result of previous concerted efforts; for example, tens of billions of dollars of investment in strengthening infrastructure was motivated in large part by the 1989 magnitude 6.9 Loma Prieta earthquake. To build on efforts to reduce earthquake risk in the San Francisco Bay region, the HayWired earthquake scenario comprehensively examines the earthquake hazards to help provide the crucial scientific information that the San Francisco Bay region can use to prepare for the next large earthquake, The HayWired Earthquake Scenario—Earthquake Hazards volume describes the strong ground shaking modeled in the scenario and the hazardous movements of
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A smartphone application for earthquakes that matter!
Bossu, Rémy; Etivant, Caroline; Roussel, Fréderic; Mazet-Roux, Gilles; Steed, Robert
2014-05-01
level of shaking intensity with empirical models of fatality losses calibrated on past earthquakes in each country. Non-seismic detections and macroseismic questionnaires collected online are combined to identify as many as possible of the felt earthquakes regardless their magnitude. Non seismic detections include Twitter earthquake detections, developed by the US Geological Survey, where the number of tweets containing the keyword "earthquake" is monitored in real time and flashsourcing, developed by the EMSC, which detect traffic surges on its rapid earthquake information website caused by the natural convergence of eyewitnesses who rush to the Internet to investigate the cause of the shaking that they have just felt. All together, we estimate that the number of detected felt earthquakes is around 1 000 per year, compared with the 35 000 earthquakes annually reported by the EMSC! Felt events are already the subject of the web page "Latest significant earthquakes" on EMSC website (http://www.emsc-csem.org/Earthquake/significant_earthquakes.php) and of a dedicated Twitter service @LastQuake. We will present the identification process of the earthquakes that matter, the smartphone application itself (to be released in May) and its future evolutions.
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Directory of Open Access Journals (Sweden)
Bondarescu Mihai
2015-01-01
Full Text Available Modern optical atomic clocks along with the optical fiber technology currently being developed can measure the geoid, which is the equipotential surface that extends the mean sea level on continents, to a precision that competes with existing technology. In this proceeding, we point out that atomic clocks have the potential to not only map the sea level surface on continents, but also look at variations of the geoid as a function of time with unprecedented timing resolution. The local time series of the geoid has a plethora of applications. These include potential improvement in the predictions of earthquakes and volcanoes, and closer monitoring of ground uplift in areas where hydraulic fracturing is performed.
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The 2016 Central Italy Earthquake: an Overview
Amato, A.
2016-12-01
The M6 central Italy earthquake occurred on the seismic backbone of the Italy, just in the middle of the highest hazard belt. The shock hit suddenly during the night of August 24, when people were asleep; no foreshocks occurred before the main event. The earthquake ruptured from 10 km to the surface, and produced a more than 17,000 aftershocks (Oct. 19) spread on a 40x20 km2 area elongated NW-SE. It is geologically very similar to previous recent events of the Apennines. Both the 2009 L'Aquila earthquake to the south and the 1997 Colfiorito to the north, were characterized by the activation of adjacent fault segments. Despite its magnitude and the well known seismic hazard of the region, the earthquake produced extensive damage and 297 fatalities. The town of Amatrice, that paid the highest toll, was classified in zone 1 (the highest) since 1915, but the buildings in this and other villages revealed highly vulnerable. In contrast, in the town of Norcia, that also experienced strong ground shaking, no collapses occurred, most likely due to the retrofitting carried out after an earthquake in 1979. Soon after the quake, the INGV Crisis Unit convened at night in the Rome headquarters, in order to coordinate the activities. The first field teams reached the epicentral area at 7 am with the portable seismic stations installed to monitor the aftershocks; other teams followed to map surface faults, damage, to measure GPS sites, to install instruments for site response studies, and so on. The INGV Crisis Unit includes the Press office and the INGVterremoti team, in order to manage and coordinate the communication towards the Civil Protection Dept. (DPC), the media and the web. Several tens of reports and updates have been delivered in the first month of the sequence to DPC. Also due to the controversial situation arisen from the L'Aquila earthquake and trials, particular attention was given to the communication: continuous and timely information has been released to
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Critical behavior in earthquake energy dissipation
Wanliss, James; Muñoz, Víctor; Pastén, Denisse; Toledo, Benjamín; Valdivia, Juan Alejandro
2017-09-01
We explore bursty multiscale energy dissipation from earthquakes flanked by latitudes 29° S and 35.5° S, and longitudes 69.501° W and 73.944° W (in the Chilean central zone). Our work compares the predictions of a theory of nonequilibrium phase transitions with nonstandard statistical signatures of earthquake complex scaling behaviors. For temporal scales less than 84 hours, time development of earthquake radiated energy activity follows an algebraic arrangement consistent with estimates from the theory of nonequilibrium phase transitions. There are no characteristic scales for probability distributions of sizes and lifetimes of the activity bursts in the scaling region. The power-law exponents describing the probability distributions suggest that the main energy dissipation takes place due to largest bursts of activity, such as major earthquakes, as opposed to smaller activations which contribute less significantly though they have greater relative occurrence. The results obtained provide statistical evidence that earthquake energy dissipation mechanisms are essentially "scale-free", displaying statistical and dynamical self-similarity. Our results provide some evidence that earthquake radiated energy and directed percolation belong to a similar universality class.
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Investigation of the relationship between ionospheric foF2 and earthquakes
Karaboga, Tuba; Canyilmaz, Murat; Ozcan, Osman
2018-04-01
Variations of the ionospheric F2 region critical frequency (foF2) have been investigated statistically before earthquakes during 1980-2008 periods in Japan area. Ionosonde data was taken from Kokubunji station which is in the earthquake preparation zone for all earthquakes. Standard Deviations and Inter-Quartile Range methods are applied to the foF2 data. It is observed that there are anomalous variations in foF2 before earthquakes. These variations can be regarded as ionospheric precursors and may be used for earthquake prediction.
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Czech Academy of Sciences Publication Activity Database
Fischer, Tomáš; Matyska, C.; Heinicke, J.
2017-01-01
Roč. 460, February (2017), s. 60-67 ISSN 0012-821X R&D Projects: GA MŠk LM2010008 Institutional support: RVO:67985530 Keywords : earthquake swarms * fluid triggering * crustal CO2 * fault valve Subject RIV: DC - Siesmology, Volcanology, Earth Structure OBOR OECD: Volcanology Impact factor: 4.409, year: 2016
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Areas prone to slow slip events impede earthquake rupture propagation and promote afterslip
Rolandone, Frederique; Nocquet, Jean-Mathieu; Mothes, Patricia A.; Jarrin, Paul; Vallée, Martin; Cubas, Nadaya; Hernandez, Stephen; Plain, Morgan; Vaca, Sandro; Font, Yvonne
2018-01-01
At subduction zones, transient aseismic slip occurs either as afterslip following a large earthquake or as episodic slow slip events during the interseismic period. Afterslip and slow slip events are usually considered as distinct processes occurring on separate fault areas governed by different frictional properties. Continuous GPS (Global Positioning System) measurements following the 2016 Mw (moment magnitude) 7.8 Ecuador earthquake reveal that large and rapid afterslip developed at discrete areas of the megathrust that had previously hosted slow slip events. Regardless of whether they were locked or not before the earthquake, these areas appear to persistently release stress by aseismic slip throughout the earthquake cycle and outline the seismic rupture, an observation potentially leading to a better anticipation of future large earthquakes. PMID:29404404
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Earthquake cycles and physical modeling of the process leading up to a large earthquake
Ohnaka, Mitiyasu
2004-08-01
A thorough discussion is made on what the rational constitutive law for earthquake ruptures ought to be from the standpoint of the physics of rock friction and fracture on the basis of solid facts observed in the laboratory. From this standpoint, it is concluded that the constitutive law should be a slip-dependent law with parameters that may depend on slip rate or time. With the long-term goal of establishing a rational methodology of forecasting large earthquakes, the entire process of one cycle for a typical, large earthquake is modeled, and a comprehensive scenario that unifies individual models for intermediate-and short-term (immediate) forecasts is presented within the framework based on the slip-dependent constitutive law and the earthquake cycle model. The earthquake cycle includes the phase of accumulation of elastic strain energy with tectonic loading (phase II), and the phase of rupture nucleation at the critical stage where an adequate amount of the elastic strain energy has been stored (phase III). Phase II plays a critical role in physical modeling of intermediate-term forecasting, and phase III in physical modeling of short-term (immediate) forecasting. The seismogenic layer and individual faults therein are inhomogeneous, and some of the physical quantities inherent in earthquake ruptures exhibit scale-dependence. It is therefore critically important to incorporate the properties of inhomogeneity and physical scaling, in order to construct realistic, unified scenarios with predictive capability. The scenario presented may be significant and useful as a necessary first step for establishing the methodology for forecasting large earthquakes.
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New characteristics of intensity assessment of Sichuan Lushan "4.20" M s7.0 earthquake
Sun, Baitao; Yan, Peilei; Chen, Xiangzhao
2014-08-01
The post-earthquake rapid accurate assessment of macro influence of seismic ground motion is of significance for earthquake emergency relief, post-earthquake reconstruction and scientific research. The seismic intensity distribution map released by the Lushan earthquake field team of the China Earthquake Administration (CEA) five days after the strong earthquake ( M7.0) occurred in Lushan County of Sichuan Ya'an City at 8:02 on April 20, 2013 provides a scientific basis for emergency relief, economic loss assessment and post-earthquake reconstruction. In this paper, the means for blind estimation of macroscopic intensity, field estimation of macro intensity, and review of intensity, as well as corresponding problems are discussed in detail, and the intensity distribution characteristics of the Lushan "4.20" M7.0 earthquake and its influential factors are analyzed, providing a reference for future seismic intensity assessments.
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Ground Motion Prediction Model Using Artificial Neural Network
Dhanya, J.; Raghukanth, S. T. G.
2018-03-01
This article focuses on developing a ground motion prediction equation based on artificial neural network (ANN) technique for shallow crustal earthquakes. A hybrid technique combining genetic algorithm and Levenberg-Marquardt technique is used for training the model. The present model is developed to predict peak ground velocity, and 5% damped spectral acceleration. The input parameters for the prediction are moment magnitude ( M w), closest distance to rupture plane ( R rup), shear wave velocity in the region ( V s30) and focal mechanism ( F). A total of 13,552 ground motion records from 288 earthquakes provided by the updated NGA-West2 database released by Pacific Engineering Research Center are utilized to develop the model. The ANN architecture considered for the model consists of 192 unknowns including weights and biases of all the interconnected nodes. The performance of the model is observed to be within the prescribed error limits. In addition, the results from the study are found to be comparable with the existing relations in the global database. The developed model is further demonstrated by estimating site-specific response spectra for Shimla city located in Himalayan region.
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Regional Seismic Amplitude Modeling and Tomography for Earthquake-Explosion Discrimination
Walter, W. R.; Pasyanos, M. E.; Matzel, E.; Gok, R.; Sweeney, J.; Ford, S. R.; Rodgers, A. J.
2008-12-01
Empirically explosions have been discriminated from natural earthquakes using regional amplitude ratio techniques such as P/S in a variety of frequency bands. We demonstrate that such ratios discriminate nuclear tests from earthquakes using closely located pairs of earthquakes and explosions recorded on common, publicly available stations at test sites around the world (e.g. Nevada, Novaya Zemlya, Semipalatinsk, Lop Nor, India, Pakistan, and North Korea). We are examining if there is any relationship between the observed P/S and the point source variability revealed by longer period full waveform modeling. For example, regional waveform modeling shows strong tectonic release from the May 1998 India test, in contrast with very little tectonic release in the October 2006 North Korea test, but the P/S discrimination behavior appears similar in both events using the limited regional data available. While regional amplitude ratios such as P/S can separate events in close proximity, it is also empirically well known that path effects can greatly distort observed amplitudes and make earthquakes appear very explosion-like. Previously we have shown that the MDAC (Magnitude Distance Amplitude Correction, Walter and Taylor, 2001) technique can account for simple 1-D attenuation and geometrical spreading corrections, as well as magnitude and site effects. However in some regions 1-D path corrections are a poor approximation and we need to develop 2-D path corrections. Here we demonstrate a new 2-D attenuation tomography technique using the MDAC earthquake source model applied to a set of events and stations in both the Middle East and the Yellow Sea Korean Peninsula regions. We believe this new 2-D MDAC tomography has the potential to greatly improve earthquake-explosion discrimination, particularly in tectonically complex regions such as the Middle East.
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Earthquake risk assessment of building structures
International Nuclear Information System (INIS)
Ellingwood, Bruce R.
2001-01-01
During the past two decades, probabilistic risk analysis tools have been applied to assess the performance of new and existing building structural systems. Structural design and evaluation of buildings and other facilities with regard to their ability to withstand the effects of earthquakes requires special considerations that are not normally a part of such evaluations for other occupancy, service and environmental loads. This paper reviews some of these special considerations, specifically as they pertain to probability-based codified design and reliability-based condition assessment of existing buildings. Difficulties experienced in implementing probability-based limit states design criteria for earthquake are summarized. Comparisons of predicted and observed building damage highlight the limitations of using current deterministic approaches for post-earthquake building condition assessment. The importance of inherent randomness and modeling uncertainty in forecasting building performance is examined through a building fragility assessment of a steel frame with welded connections that was damaged during the Northridge Earthquake of 1994. The prospects for future improvements in earthquake-resistant design procedures based on a more rational probability-based treatment of uncertainty are examined
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Dynamic strains for earthquake source characterization
Barbour, Andrew J.; Crowell, Brendan W
2017-01-01
Strainmeters measure elastodynamic deformation associated with earthquakes over a broad frequency band, with detection characteristics that complement traditional instrumentation, but they are commonly used to study slow transient deformation along active faults and at subduction zones, for example. Here, we analyze dynamic strains at Plate Boundary Observatory (PBO) borehole strainmeters (BSM) associated with 146 local and regional earthquakes from 2004–2014, with magnitudes from M 4.5 to 7.2. We find that peak values in seismic strain can be predicted from a general regression against distance and magnitude, with improvements in accuracy gained by accounting for biases associated with site–station effects and source–path effects, the latter exhibiting the strongest influence on the regression coefficients. To account for the influence of these biases in a general way, we include crustal‐type classifications from the CRUST1.0 global velocity model, which demonstrates that high‐frequency strain data from the PBO BSM network carry information on crustal structure and fault mechanics: earthquakes nucleating offshore on the Blanco fracture zone, for example, generate consistently lower dynamic strains than earthquakes around the Sierra Nevada microplate and in the Salton trough. Finally, we test our dynamic strain prediction equations on the 2011 M 9 Tohoku‐Oki earthquake, specifically continuous strain records derived from triangulation of 137 high‐rate Global Navigation Satellite System Earth Observation Network stations in Japan. Moment magnitudes inferred from these data and the strain model are in agreement when Global Positioning System subnetworks are unaffected by spatial aliasing.
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Effects of Strike-Slip Fault Segmentation on Earthquake Energy and Seismic Hazard
Madden, E. H.; Cooke, M. L.; Savage, H. M.; McBeck, J.
2014-12-01
Many major strike-slip faults are segmented along strike, including those along plate boundaries in California and Turkey. Failure of distinct fault segments at depth may be the source of multiple pulses of seismic radiation observed for single earthquakes. However, how and when segmentation affects fault behavior and energy release is the basis of many outstanding questions related to the physics of faulting and seismic hazard. These include the probability for a single earthquake to rupture multiple fault segments and the effects of segmentation on earthquake magnitude, radiated seismic energy, and ground motions. Using numerical models, we quantify components of the earthquake energy budget, including the tectonic work acting externally on the system, the energy of internal rock strain, the energy required to overcome fault strength and initiate slip, the energy required to overcome frictional resistance during slip, and the radiated seismic energy. We compare the energy budgets of systems of two en echelon fault segments with various spacing that include both releasing and restraining steps. First, we allow the fault segments to fail simultaneously and capture the effects of segmentation geometry on the earthquake energy budget and on the efficiency with which applied displacement is accommodated. Assuming that higher efficiency correlates with higher probability for a single, larger earthquake, this approach has utility for assessing the seismic hazard of segmented faults. Second, we nucleate slip along a weak portion of one fault segment and let the quasi-static rupture propagate across the system. Allowing fractures to form near faults in these models shows that damage develops within releasing steps and promotes slip along the second fault, while damage develops outside of restraining steps and can prohibit slip along the second fault. Work is consumed in both the propagation of and frictional slip along these new fractures, impacting the energy available
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Strain Anomalies during an Earthquake Sequence in the South Iceland Seismic Zone
Arnadottir, T.; Haines, A. J.; Geirsson, H.; Hreinsdottir, S.
2017-12-01
The South Iceland Seismic Zone (SISZ) accommodates E-W translation due to oblique spreading between the North American/Hreppar microplate and Eurasian plate, in South Iceland. Strain is released in the SISZ during earthquake sequences that last days to years, at average intervals of 80-100 years. The SISZ is currently in the midst of an earthquake sequence that started with two M6.5 earthquakes in June 2000, and continued with two M6 earthquakes in May 2008. Estimates of geometric strain accumulation, and seismic strain release in these events indicate that they released at most only half of the strain accumulated since the last earthquake cycle in 1896-1912. Annual GPS campaigns and continuous measurements during 2001-2015 were used to calculate station velocities and strain rates from a new method using the vertical derivatives of horizontal stress (VDoHS). This new method allows higher resolution of strain rates than other (older) approaches, as the strain rates are estimated by integrating VDoHS rates obtained by inversion rather than differentiating interpolated GPS velocities. Estimating the strain rates for eight 1-2 year intervals indicates temporal and spatial variation of strain rates in the SISZ. In addition to earthquake faulting, the strain rates in the SISZ are influenced by anthropogenic signals due to geothermal exploitation, and magma movements in neighboring volcanoes - Hekla and Eyjafjallajökull. Subtle signals of post-seismic strain rate changes are seen following the June 2000 M6.5 main shocks, but interestingly, much larger strain rate variations are observed after the two May 2008 M6 main shocks. A prominent strain anomaly is evident in the epicentral area prior to the May 2008 earthquake sequence. The strain signal persists over at least 4 years in the epicentral area, leading up to the M6 main shocks. The strain is primarily extension in ESE-WNW direction (sub-parallel to the direction of plate spreading), but overall shear across the N
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Shapira, Stav; Novack, Lena; Bar-Dayan, Yaron; Aharonson-Daniel, Limor
2016-01-01
A comprehensive technique for earthquake-related casualty estimation remains an unmet challenge. This study aims to integrate risk factors related to characteristics of the exposed population and to the built environment in order to improve communities' preparedness and response capabilities and to mitigate future consequences. An innovative model was formulated based on a widely used loss estimation model (HAZUS) by integrating four human-related risk factors (age, gender, physical disability and socioeconomic status) that were identified through a systematic review and meta-analysis of epidemiological data. The common effect measures of these factors were calculated and entered to the existing model's algorithm using logistic regression equations. Sensitivity analysis was performed by conducting a casualty estimation simulation in a high-vulnerability risk area in Israel. the integrated model outcomes indicated an increase in the total number of casualties compared with the prediction of the traditional model; with regard to specific injury levels an increase was demonstrated in the number of expected fatalities and in the severely and moderately injured, and a decrease was noted in the lightly injured. Urban areas with higher populations at risk rates were found more vulnerable in this regard. The proposed model offers a novel approach that allows quantification of the combined impact of human-related and structural factors on the results of earthquake casualty modelling. Investing efforts in reducing human vulnerability and increasing resilience prior to an occurrence of an earthquake could lead to a possible decrease in the expected number of casualties.
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Performance of HEPA filters at LLNL following the 1980 and 1989 earthquakes
International Nuclear Information System (INIS)
Bergman, W.; Elliott, J.; Wilson, K.
1995-01-01
The Lawrence Livermore National Laboratory has experienced two significant earthquakes for which data is available to assess the ability of HEPA filters to withstand seismic conditions. A 5.9 magnitude earthquake with an epicenter 10 miles from LLNL struck on January 24, l980. Estimates of the peak ground accelerations ranged from 0.2 to 0.3 g. A 7.0 magnitude earthquake with an epicenter about 50 miles from LLNL struck on October 17, 1989. Measurements of the ground accelerations at LLNL averaged 0.1 g. The results from the in-place filter tests obtained after each of the earthquakes were compiled and studied to determine if the earthquakes had caused filter leakage. Our study showed that only the 1980 earthquake resulted in a small increase in the number of HEPA filters developing leaks. In the 12 months following the 1980 and 1989 earthquakes, the in-place filter tests showed 8.0% and 4.1% of all filters respectively developed leaks. The average percentage of filters developing leaks from 1980 to 1993 was 3.3%+/-1.7%. The increase in the filter leaks is significant for the 1980 earthquake, but not for the 1989 earthquake. No contamination was detected following the earthquakes that would suggest transient releases from the filtration system
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Performance of HEPA filters at LLNL following the 1980 and 1989 earthquakes
Energy Technology Data Exchange (ETDEWEB)
Bergman, W.; Elliott, J.; Wilson, K. [Lawrence Livermore National Laboratory, CA (United States)
1995-02-01
The Lawrence Livermore National Laboratory has experienced two significant earthquakes for which data is available to assess the ability of HEPA filters to withstand seismic conditions. A 5.9 magnitude earthquake with an epicenter 10 miles from LLNL struck on January 24, l980. Estimates of the peak ground accelerations ranged from 0.2 to 0.3 g. A 7.0 magnitude earthquake with an epicenter about 50 miles from LLNL struck on October 17, 1989. Measurements of the ground accelerations at LLNL averaged 0.1 g. The results from the in-place filter tests obtained after each of the earthquakes were compiled and studied to determine if the earthquakes had caused filter leakage. Our study showed that only the 1980 earthquake resulted in a small increase in the number of HEPA filters developing leaks. In the 12 months following the 1980 and 1989 earthquakes, the in-place filter tests showed 8.0% and 4.1% of all filters respectively developed leaks. The average percentage of filters developing leaks from 1980 to 1993 was 3.3%+/-1.7%. The increase in the filter leaks is significant for the 1980 earthquake, but not for the 1989 earthquake. No contamination was detected following the earthquakes that would suggest transient releases from the filtration system.
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Rockabrand, Ryan
2017-01-01
Approved for public release; distribution is unlimited The United States is extremely vulnerable to catastrophic earthquakes. More than 143 million Americans may be threatened by damaging earthquakes in the next 50 years. This thesis argues that the United States is unprepared for the most catastrophic earthquakes the country faces today. Earthquake early warning systems are a major solution in practice to reduce economic risk, to protect property and the environment, and to save lives. Ot...
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Experimental evidence that thrust earthquake ruptures might open faults.
Gabuchian, Vahe; Rosakis, Ares J; Bhat, Harsha S; Madariaga, Raúl; Kanamori, Hiroo
2017-05-18
Many of Earth's great earthquakes occur on thrust faults. These earthquakes predominantly occur within subduction zones, such as the 2011 moment magnitude 9.0 eathquake in Tohoku-Oki, Japan, or along large collision zones, such as the 1999 moment magnitude 7.7 earthquake in Chi-Chi, Taiwan. Notably, these two earthquakes had a maximum slip that was very close to the surface. This contributed to the destructive tsunami that occurred during the Tohoku-Oki event and to the large amount of structural damage caused by the Chi-Chi event. The mechanism that results in such large slip near the surface is poorly understood as shallow parts of thrust faults are considered to be frictionally stable. Here we use earthquake rupture experiments to reveal the existence of a torquing mechanism of thrust fault ruptures near the free surface that causes them to unclamp and slip large distances. Complementary numerical modelling of the experiments confirms that the hanging-wall wedge undergoes pronounced rotation in one direction as the earthquake rupture approaches the free surface, and this torque is released as soon as the rupture breaks the free surface, resulting in the unclamping and violent 'flapping' of the hanging-wall wedge. Our results imply that the shallow extent of the seismogenic zone of a subducting interface is not fixed and can extend up to the trench during great earthquakes through a torquing mechanism.
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Rapid acceleration leads to rapid weakening in earthquake-like laboratory experiments
Chang, Jefferson C.; Lockner, David A.; Reches, Z.
2012-01-01
After nucleation, a large earthquake propagates as an expanding rupture front along a fault. This front activates countless fault patches that slip by consuming energy stored in Earth’s crust. We simulated the slip of a fault patch by rapidly loading an experimental fault with energy stored in a spinning flywheel. The spontaneous evolution of strength, acceleration, and velocity indicates that our experiments are proxies of fault-patch behavior during earthquakes of moment magnitude (Mw) = 4 to 8. We show that seismically determined earthquake parameters (e.g., displacement, velocity, magnitude, or fracture energy) can be used to estimate the intensity of the energy release during an earthquake. Our experiments further indicate that high acceleration imposed by the earthquake’s rupture front quickens dynamic weakening by intense wear of the fault zone.
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Correlation between Earthquakes and AE Monitoring of Historical Buildings in Seismic Areas
Directory of Open Access Journals (Sweden)
Giuseppe Lacidogna
2015-12-01
Full Text Available In this contribution a new method for evaluating seismic risk in regional areas based on the acoustic emission (AE technique is proposed. Most earthquakes have precursors, i.e., phenomena of changes in the Earth’s physical-chemical properties that take place prior to an earthquake. Acoustic emissions in materials and earthquakes in the Earth’s crust, despite the fact that they take place on very different scales, are very similar phenomena; both are caused by a release of elastic energy from a source located in a medium. For the AE monitoring, two important constructions of Italian cultural heritage are considered: the chapel of the “Sacred Mountain of Varallo” and the “Asinelli Tower” of Bologna. They were monitored during earthquake sequences in their relative areas. By using the Grassberger-Procaccia algorithm, a statistical method of analysis was developed that detects AEs as earthquake precursors or aftershocks. Under certain conditions it was observed that AEs precede earthquakes. These considerations reinforce the idea that the AE monitoring can be considered an effective tool for earthquake risk evaluation.
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Lessons of L'Aquila for Operational Earthquake Forecasting
Jordan, T. H.
2012-12-01
The L'Aquila earthquake of 6 Apr 2009 (magnitude 6.3) killed 309 people and left tens of thousands homeless. The mainshock was preceded by a vigorous seismic sequence that prompted informal earthquake predictions and evacuations. In an attempt to calm the population, the Italian Department of Civil Protection (DPC) convened its Commission on the Forecasting and Prevention of Major Risk (MRC) in L'Aquila on 31 March 2009 and issued statements about the hazard that were widely received as an "anti-alarm"; i.e., a deterministic prediction that there would not be a major earthquake. On October 23, 2012, a court in L'Aquila convicted the vice-director of DPC and six scientists and engineers who attended the MRC meeting on charges of criminal manslaughter, and it sentenced each to six years in prison. A few weeks after the L'Aquila disaster, the Italian government convened an International Commission on Earthquake Forecasting for Civil Protection (ICEF) with the mandate to assess the status of short-term forecasting methods and to recommend how they should be used in civil protection. The ICEF, which I chaired, issued its findings and recommendations on 2 Oct 2009 and published its final report, "Operational Earthquake Forecasting: Status of Knowledge and Guidelines for Implementation," in Aug 2011 (www.annalsofgeophysics.eu/index.php/annals/article/view/5350). As defined by the Commission, operational earthquake forecasting (OEF) involves two key activities: the continual updating of authoritative information about the future occurrence of potentially damaging earthquakes, and the officially sanctioned dissemination of this information to enhance earthquake preparedness in threatened communities. Among the main lessons of L'Aquila is the need to separate the role of science advisors, whose job is to provide objective information about natural hazards, from that of civil decision-makers who must weigh the benefits of protective actions against the costs of false alarms
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Operational Earthquake Forecasting and Decision-Making in a Low-Probability Environment
Jordan, T. H.; the International Commission on Earthquake ForecastingCivil Protection
2011-12-01
Operational earthquake forecasting (OEF) is the dissemination of authoritative information about the time dependence of seismic hazards to help communities prepare for potentially destructive earthquakes. Most previous work on the public utility of OEF has anticipated that forecasts would deliver high probabilities of large earthquakes; i.e., deterministic predictions with low error rates (false alarms and failures-to-predict) would be possible. This expectation has not been realized. An alternative to deterministic prediction is probabilistic forecasting based on empirical statistical models of aftershock triggering and seismic clustering. During periods of high seismic activity, short-term earthquake forecasts can attain prospective probability gains in excess of 100 relative to long-term forecasts. The utility of such information is by no means clear, however, because even with hundredfold increases, the probabilities of large earthquakes typically remain small, rarely exceeding a few percent over forecasting intervals of days or weeks. Civil protection agencies have been understandably cautious in implementing OEF in this sort of "low-probability environment." The need to move more quickly has been underscored by recent seismic crises, such as the 2009 L'Aquila earthquake sequence, in which an anxious public was confused by informal and inaccurate earthquake predictions. After the L'Aquila earthquake, the Italian Department of Civil Protection appointed an International Commission on Earthquake Forecasting (ICEF), which I chaired, to recommend guidelines for OEF utilization. Our report (Ann. Geophys., 54, 4, 2011; doi: 10.4401/ag-5350) concludes: (a) Public sources of information on short-term probabilities should be authoritative, scientific, open, and timely, and need to convey epistemic uncertainties. (b) Earthquake probabilities should be based on operationally qualified, regularly updated forecasting systems. (c) All operational models should be evaluated
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Extending the ISC-GEM Global Earthquake Instrumental Catalogue
Di Giacomo, Domenico; Engdhal, Bob; Storchak, Dmitry; Villaseñor, Antonio; Harris, James
2015-04-01
After a 27-month project funded by the GEM Foundation (www.globalquakemodel.org), in January 2013 we released the ISC-GEM Global Instrumental Earthquake Catalogue (1900 2009) (www.isc.ac.uk/iscgem/index.php) as a special product to use for seismic hazard studies. The new catalogue was necessary as improved seismic hazard studies necessitate that earthquake catalogues are homogeneous (to the largest extent possible) over time in their fundamental parameters, such as location and magnitude. Due to time and resource limitation, the ISC-GEM catalogue (1900-2009) included earthquakes selected according to the following time-variable cut-off magnitudes: Ms=7.5 for earthquakes occurring before 1918; Ms=6.25 between 1918 and 1963; and Ms=5.5 from 1964 onwards. Because of the importance of having a reliable seismic input for seismic hazard studies, funding from GEM and two commercial companies in the US and UK allowed us to start working on the extension of the ISC-GEM catalogue both for earthquakes that occurred beyond 2009 and for earthquakes listed in the International Seismological Summary (ISS) which fell below the cut-off magnitude of 6.25. This extension is part of a four-year program that aims at including in the ISC-GEM catalogue large global earthquakes that occurred before the beginning of the ISC Bulletin in 1964. In this contribution we present the updated ISC GEM catalogue, which will include over 1000 more earthquakes that occurred in 2010 2011 and several hundreds more between 1950 and 1959. The catalogue extension between 1935 and 1949 is currently underway. The extension of the ISC-GEM catalogue will also be helpful for regional cross border seismic hazard studies as the ISC-GEM catalogue should be used as basis for cross-checking the consistency in location and magnitude of those earthquakes listed both in the ISC GEM global catalogue and regional catalogues.
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Report by the 'Mega-earthquakes and mega-tsunamis' subgroup
International Nuclear Information System (INIS)
Friedel, Jacques; Courtillot, Vincent; Dercourt, Jean; Jaupart, Claude; Le Pichon, Xavier; Poirier, Jean-Paul; Salencon, Jean; Tapponnier, Paul; Dautray, Robert; Carpentier, Alain; Taquet, Philippe; Blanchet, Rene; Le Mouel, Jean-Louis; BARD, Pierre-Yves; Bernard, Pascal; Montagner, Jean-Paul; Armijo, Rolando; Shapiro, Nikolai; Tait, Steve; Cara, Michel; Madariaga, Raul; Pecker, Alain; Schindele, Francois; Douglas, John
2011-06-01
This report comprises a presentation of scientific data on subduction earthquakes, on tsunamis and on the Tohoku earthquake. It proposes a detailed description of the French situation (in the West Indies, in metropolitan France, and in terms of soil response), and a discussion of social and economic issues (governance, seismic regulation and nuclear safety, para-seismic protection of constructions). The report is completed by other large documents: presentation of data on the Japanese earthquake, discussion on prediction and governance errors in the management of earthquake mitigation in Japan, discussions on tsunami prevention, on needs of research on accelerometers, and on the seismic risk in France
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Radon, gas geochemistry, groundwater, and earthquakes
Energy Technology Data Exchange (ETDEWEB)
King, Chi-Yu [Power Reactor and Nuclear Fuel Development Corp., Tono Geoscience Center, Toki, Gifu (Japan)
1998-12-31
Radon monitoring in groundwater, soil air, and atmosphere has been continued in many seismic areas of the world for earthquake-prediction and active-fault studies. Some recent measurements of radon and other geochemical and hydrological parameters have been made for sufficiently long periods, with reliable instruments, and together with measurements of meteorological variables and solid-earth tides. The resultant data are useful in better distinguishing earthquake-related changes from various background noises. Some measurements have been carried out in areas where other geophysical measurements are being made also. Comparative studies of various kinds of geophysical data are helpful in ascertaining the reality of the earthquake-related and fault-related anomalies and in understanding the underlying mechanisms. Spatial anomalies of radon and other terrestrial gasses have been observed for many active faults. Such observations indicate that gas concentrations are very much site dependent, particularly on fault zones where terrestrial fluids may move vertically. Temporal anomalies have been reliably observed before and after some recent earthquakes, including the 1995 Kobe earthquake, and the general pattern of anomaly occurrence remains the same as observed before: They are recorded at only relatively few sensitive sites, which can be at much larger distances than expected from existing earthquake-source models. The sensitivity of a sensitive site is also found to be changeable with time. These results clearly show the inadequacy of the existing dilatancy-fluid diffusion and elastic-dislocation models for earthquake sources to explain earthquake-related geochemical and geophysical changes recorded at large distances. (J.P.N.)
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R, A. P.; Paul, A.; Singh, S.
2017-12-01
Since the continent-continent collision 55 Ma, the Himalaya has accommodated 2000 km of convergence along its arc. The strain energy is being accumulated at a rate of 37-44 mm/yr and releases at time as earthquakes. The Garhwal Himalaya is located at the western side of a Seismic Gap, where a great earthquake is overdue atleast since 200 years. This seismic gap (Central Seismic Gap: CSG) with 52% probability for a future great earthquake is located between the rupture zones of two significant/great earthquakes, viz. the 1905 Kangra earthquake of M 7.8 and the 1934 Bihar-Nepal earthquake of M 8.0; and the most recent one, the 2015 Gorkha earthquake of M 7.8 is in the eastern side of this seismic gap (CSG). The Garhwal Himalaya is one of the ideal locations of the Himalaya where all the major Himalayan structures and the Himalayan Seimsicity Belt (HSB) can ably be described and studied. In the present study, we are presenting the spatio-temporal analysis of the relocated local micro-moderate earthquakes, recorded by a seismicity monitoring network, which is operational since, 2007. The earthquake locations are relocated using the HypoDD (double difference hypocenter method for earthquake relocations) program. The dataset from July, 2007- September, 2015 have been used in this study to estimate their spatio-temporal relationships, moment tensor (MT) solutions for the earthquakes of M>3.0, stress tensors and their interactions. We have also used the composite focal mechanism solutions for small earthquakes. The majority of the MT solutions show thrust type mechanism and located near the mid-crustal-ramp (MCR) structure of the detachment surface at 8-15 km depth beneath the outer lesser Himalaya and higher Himalaya regions. The prevailing stress has been identified to be compressional towards NNE-SSW, which is the direction of relative plate motion between the India and Eurasia continental plates. The low friction coefficient estimated along with the stress inversions
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Characteristics of broadband slow earthquakes explained by a Brownian model
Ide, S.; Takeo, A.
2017-12-01
Brownian slow earthquake (BSE) model (Ide, 2008; 2010) is a stochastic model for the temporal change of seismic moment release by slow earthquakes, which can be considered as a broadband phenomena including tectonic tremors, low frequency earthquakes, and very low frequency (VLF) earthquakes in the seismological frequency range, and slow slip events in geodetic range. Although the concept of broadband slow earthquake may not have been widely accepted, most of recent observations are consistent with this concept. Then, we review the characteristics of slow earthquakes and how they are explained by BSE model. In BSE model, the characteristic size of slow earthquake source is represented by a random variable, changed by a Gaussian fluctuation added at every time step. The model also includes a time constant, which divides the model behavior into short- and long-time regimes. In nature, the time constant corresponds to the spatial limit of tremor/SSE zone. In the long-time regime, the seismic moment rate is constant, which explains the moment-duration scaling law (Ide et al., 2007). For a shorter duration, the moment rate increases with size, as often observed for VLF earthquakes (Ide et al., 2008). The ratio between seismic energy and seismic moment is constant, as shown in Japan, Cascadia, and Mexico (Maury et al., 2017). The moment rate spectrum has a section of -1 slope, limited by two frequencies corresponding to the above time constant and the time increment of the stochastic process. Such broadband spectra have been observed for slow earthquakes near the trench axis (Kaneko et al., 2017). This spectrum also explains why we can obtain VLF signals by stacking broadband seismograms relative to tremor occurrence (e.g., Takeo et al., 2010; Ide and Yabe, 2014). The fluctuation in BSE model can be non-Gaussian, as far as the variance is finite, as supported by the central limit theorem. Recent observations suggest that tremors and LFEs are spatially characteristic
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Comparison of the November 2002 Denali and November 2001 Kunlun Earthquakes
Bufe, C. G.
2002-12-01
Major earthquakes occurred in Tibet on the central Kunlun fault (M 7.8) on November 14, 2001 (Lin and others, 2002) and in Alaska on the central Denali fault (M 7.9) on November 3, 2002. Both earthquakes generated large surface waves (Kunlun Ms 8.0 (USGS) and Denali Ms 8.5). Each event occurred on east-west-trending strike-slip faults and exhibited nearly unilateral rupture propagating several hundred kilometers from west to east. Surface rupture length estimates were about 400 km for Kunlun, 300 km for Denali. Maximum surface faulting and moment release were observed far to the east of the points of rupture initiation. Harvard moment centroids were located east of USGS epicenters by 182 km (Kunlun) and by 126 km (Denali). Maximum surface faulting was observed near 240 km (Kunlun, 16 m left lateral) and near 175 km (Denali, 9 m right lateral) east of the USGS epicenters. Significant thrust components were observed in the initiation of the Denali event (ERI analysis and mapped thrust) and in the termination of the Kunlun rupture, as evidenced by thrust mechanisms of the largest aftershocks which occurred near the eastern part of the Kunlun rupture. In each sequence the largest aftershock was about 2 orders of magnitude smaller than the mainshock. Moment release along the ruptured segments was examined for the 25-year periods preceding the main shocks. The Denali zone shows precursory accelerating moment release with the dominant events occurring on October 22, 1996 (M 5.8) and October 23, 2002 (M 6.7). The Kunlun zone shows nearly constant moment release over time with the last significant event before the main shock occurring on November 26, 2000 (M 5.4). Moment release data are consistent with previous observations of annual periodicity preceding major earthquakes, possibly due to the evolution of a critical state with seasonal and tidal triggering (Varnes and Bufe, 2001). Annual periodicity is also evident for the larger events in the greater San Francisco Bay
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Aleksandrova, Irena; Simeonova, Stela; Solakov, Dimcho; Popova, Maria
2014-05-01
. The usable and realistic ground motion maps for urban areas are generated: - either from the assumption of a "reference earthquake" - or directly, showing values of macroseimic intensity generated by a damaging, real earthquake. In the study, applying deterministic approach, earthquake scenario in macroseismic intensity ("model" earthquake scenario) for the city of Sofia is generated. The deterministic "model" intensity scenario based on assumption of a "reference earthquake" is compared with a scenario based on observed macroseimic effects caused by the damaging 2012 earthquake (MW5.6). The difference between observed (Io) and predicted (Ip) intensities values is analyzed.
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Wrightwood and the earthquake cycle: What a long recurrence record tells us about how faults work
Weldon, R.; Scharer, K.; Fumal, T.; Biasi, G.
2004-01-01
The concept of the earthquake cycle is so well established that one often hears statements in the popular media like, "the Big One is overdue" and "the longer it waits, the bigger it will be." Surprisingly, data to critically test the variability in recurrence intervals, rupture displacements, and relationships between the two are almost nonexistent. To generate a long series of earthquake intervals and offsets, we have conducted paleoseismic investigations across the San Andreas fault near the town of Wrightwood, California, excavating 45 trenches over 18 years, and can now provide some answers to basic questions about recurrence behavior of large earthquakes. To date, we have characterized at least 30 prehistoric earthquakes in a 6000-yr-long record, complete for the past 1500 yr and for the interval 3000-1500 B.C. For the past 1500 yr, the mean recurrence interval is 105 yr (31-165 yr for individual intervals) and the mean slip is 3.2 m (0.7-7 m per event). The series is slightly more ordered than random and has a notable cluster of events, during which strain was released at 3 times the long-term average rate. Slip associated with an earthquake is not well predicted by the interval preceding it, and only the largest two earthquakes appear to affect the time interval to the next earthquake. Generally, short intervals tend to coincide with large displacements and long intervals with small displacements. The most significant correlation we find is that earthquakes are more frequent following periods of net strain accumulation spanning multiple seismic cycles. The extent of paleoearthquake ruptures may be inferred by correlating event ages between different sites along the San Andreas fault. Wrightwood and other nearby sites experience rupture that could be attributed to overlap of relatively independent segments that each behave in a more regular manner. However, the data are equally consistent with a model in which the irregular behavior seen at Wrightwood
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Technical NoteEarthquake dates and water level changes in wells in the Eskisehir region, Turkey
Directory of Open Access Journals (Sweden)
G. Yuce
2003-01-01
Full Text Available Although satisfactory results have yet to be obtained in earthquake prediction, one of the most common indicators of an anomalous precursor is a change in groundwater level in existing wells. Further wells should thus be drilled in unconfined aquifers since these are more susceptible to seismic waves. The Eskisehir region lies in the transition zone between the Aegean extensional domain and the compressible northern Anatolian block. Limnigraphs, installed in 19 exploration wells in the Eskisehir region, recorded pre-seismic, co-seismic and post-seismic level changes during the earthquakes of 17 August Izmit (Mw= 7.4 and 12 November Duzce (Mw= 7.2 1999 that occurred along the North Anatolian Fault Zone. The Izmit and Duzce earthquakes affected groundwater levels, especially in confined aquifers. The aquifer characteristics before and after the earthquakes were unchanged so the aquifer is elastic in its behaviour. Further detailed geo-mechanical investigation of the confined aquifer in the Eskisehir region may improve understanding of earthquake prediction. Keywords: earthquake prediction, Eskisehir, hydrological warning, monitoring groundwater levels
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DEFF Research Database (Denmark)
Köyluoglu, H.U.; Nielsen, Søren R.K.; Cakmak, A.S.
1997-01-01
the arrival of the first earthquake from non-destructive vibration tests or via structural analysis. The previous excitation and displacement response time series is employed for the identification of the instantaneous softening using an ARMA model. The hysteresis parameters are updated after each earthquake....... The proposed model is next generalized for the MDOF system. Using the adapted models for the structure and the global damage state, the global damage in a future earthquake can then be estimated when a suitable earthquake model is applied. The performance of the model is illustrated on RC frames which were...
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DEFF Research Database (Denmark)
Köyluoglu, H.U.; Nielsen, Søren R.K.; Cakmak, A.S.
1994-01-01
the arrival of the first earthquake from non-destructive vibration tests or via structural analysis. The previous excitation and displacement response time series is employed for the identification of the instantaneous softening using an ARMA model. The hysteresis parameters are updated after each earthquake....... The proposed model is next generalized for the MDOF system. Using the adapted models for the structure and the global damage state, the global damage in a future earthquake can then be estimated when a suitable earthquake model is applied. The performance of the model is illustrated on RC frames which were...
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Tectonic feedback and the earthquake cycle
Lomnitz, Cinna
1985-09-01
The occurrence of cyclical instabilities along plate boundaries at regular intervals suggests that the process of earthquake causation differs in some respects from the model of elastic rebound in its simplest forms. The model of tectonic feedback modifies the concept of this original model in that it provides a physical interaction between the loading rate and the state of strain on the fault. Two examples are developed: (a) Central Chile, and (b) Mexico. The predictions of earthquake hazards for both types of models are compared.
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Earthquakes, detecting and understanding them
International Nuclear Information System (INIS)
2008-05-01
The signatures at the surface of the Earth is continually changing on a geological timescale. The tectonic plates, which make up this surface, are moving in relation to each other. On human timescale, these movements are the result of earthquakes, which suddenly, release energy accumulated over a period of time. The vibrations they produce propagate through the interior of the Earth: these are seismic waves. However, other phenomena can generate seismic waves, such as volcanoes, quarry blasts, etc. The surf of the ocean waves on the coasts, the wind in the trees and human activity (industry and road traffic) all contribute to the 'seismic background noise'. Sensors are able to detect signals from events which are then discriminated, analyzed and located. Earthquakes and active volcanoes are not distributed randomly over the surface of the globe: they mainly coincide with mountain chains and ocean trenches and ridges. 'An earthquake results from the abrupt release of the energy accumulated by movements and rubbing of different plates'. The study of the propagation of seismic waves has allowed to determine the outline of the plates inside the Earth and has highlighted their movements. There are seven major plates which are colliding, diverging or sliding past each other. Each year the continents move several centimeters with respect to one another. This process, known as 'continental drift', was finally explained by plate tectonics. The initial hypothesis for this science dates from the beginning of the 20. century, but it was not confirmed until the 1960's. It explains that convection inside the Earth is the source of the forces required for these movements. This science, as well as explaining these great movements, has provided a coherent, unifying and quantitative framework, which unites the explanations for all the geophysical phenomena under one mechanism. (authors)
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Application of geochemical methods in earthquake prediction in China
Energy Technology Data Exchange (ETDEWEB)
Fong-liang, J.; Gui-ru, L.
1981-05-01
Several geochemical anomalies were observed before the Haichen, Longling, Tangshan, and Songpan earthquakes and their strong aftershocks. They included changes in groundwater radon levels; chemical composition of the groundwater (concentration of Ca/sup + +/, Mg/sup + +/, Cl/sup -/, So/sub 4//sup , and HCO/sub 3//sup -/ ions); conductivity; and dissolved gases such as H/sub 2/, CO/sub 2/, etc. In addition, anomalous changes in water color and quality were observed before these large earthquakes. Before some events gases escaped from the surface, and there were reports of ''ground odors'' being smelled by local residents. The large amount of radon data can be grouped into long-term and short-term anomalies. The long-term anomalies have a radon emission build up time of from a few months to more than a year. The short-term anomalies have durations from a few hours or less to a few months.
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Streamflow responses in Chile to megathrust earthquakes in the 20th and 21st centuries
Mohr, Christian; Manga, Michael; Wang, Chi-yuen; Korup, Oliver
2016-04-01
Both coseismic static stress and dynamic stresses associated with seismic waves may cause responses in hydrological systems. Such responses include changes in the water level, hydrochemistry and streamflow discharge. Earthquake effects on hydrological systems provide a means to study the interaction between stress changes and regional hydrology, which is otherwise rarely possible. Chile is a country of frequent and large earthquakes and thus provides abundant opportunities to study such interactions and processes. We analyze streamflow responses in Chile to several megathrust earthquakes, including the 1943 Mw 8.1 Coquimbo, 1950 Mw 8.2 Antofagasta, 1960 Mw 9.5 Valdivia, 1985 Mw 8.0 Valparaiso, 1995 Mw 8.0 Antofagasta, 2010 Mw 8.8 Maule, and the 2014 Mw 8.2 Iquique earthquakes. We use data from 716 stream gauges distributed from the Altiplano in the North to Tierra del Fuego in the South. This network covers the Andes mountain ranges, the central valley, the Coastal Mountain ranges and (mainly in the more southern parts) the Coastal flats. We combine empirical magnitude-distance relationships, machine learning tools, and process-based modeling to characterize responses. We first assess the streamflow anomalies and relate these to topographical, hydro-climatic, geological and earthquake-related (volumetric and dynamic strain) factors using various classifiers. We then apply 1D-groundwater flow modeling to selected catchments in order to test competing hypotheses for the origin of streamflow changes. We show that the co-seismic responses of streamflow mostly involved increasing discharges. We conclude that enhanced vertical permeability can explain most streamflow responses at the regional scale. The total excess water released by a single earthquake, i.e. the Maule earthquake, yielded up to 1 km3. Against the background of megathrust earthquakes frequently hitting Chile, the amount of water released by earthquakes is substantial, particularly for the arid northern
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Velasco, A. A.; Cerda, I.; Linville, L.; Kilb, D. L.; Pankow, K. L.
2013-05-01
Changes in field stress required to trigger earthquakes have been classified in two basic ways: static and dynamic triggering. Static triggering occurs when an earthquake that releases accumulated strain along a fault stress loads a nearby fault. Dynamic triggering occurs when an earthquake is induced by the passing of seismic waves from a large mainshock located at least two or more fault lengths from the epicenter of the main shock. We investigate details of dynamic triggering using data collected from EarthScope's USArray and regional seismic networks located in the United States. Triggered events are identified using an optimized automated detector based on the ratio of short term to long term average (Antelope software). Following the automated processing, the flagged waveforms are individually analyzed, in both the time and frequency domains, to determine if the increased detection rates correspond to local earthquakes (i.e., potentially remotely triggered aftershocks). Here, we show results using this automated schema applied to data from four large, but characteristically different, earthquakes -- Chile (Mw 8.8 2010), Tokoku-Oki (Mw 9.0 2011), Baja California (Mw 7.2 2010) and Wells Nevada (Mw 6.0 2008). For each of our four mainshocks, the number of detections within the 10 hour time windows span a large range (1 to over 200) and statistically >20% of the waveforms show evidence of anomalous signals following the mainshock. The results will help provide for a better understanding of the physical mechanisms involved in dynamic earthquake triggering and will help identify zones in the continental U.S. that may be more susceptible to dynamic earthquake triggering.
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Surface Rupture Effects on Earthquake Moment-Area Scaling Relations
Luo, Yingdi; Ampuero, Jean-Paul; Miyakoshi, Ken; Irikura, Kojiro
2017-09-01
Empirical earthquake scaling relations play a central role in fundamental studies of earthquake physics and in current practice of earthquake hazard assessment, and are being refined by advances in earthquake source analysis. A scaling relation between seismic moment ( M 0) and rupture area ( A) currently in use for ground motion prediction in Japan features a transition regime of the form M 0- A 2, between the well-recognized small (self-similar) and very large (W-model) earthquake regimes, which has counter-intuitive attributes and uncertain theoretical underpinnings. Here, we investigate the mechanical origin of this transition regime via earthquake cycle simulations, analytical dislocation models and numerical crack models on strike-slip faults. We find that, even if stress drop is assumed constant, the properties of the transition regime are controlled by surface rupture effects, comprising an effective rupture elongation along-dip due to a mirror effect and systematic changes of the shape factor relating slip to stress drop. Based on this physical insight, we propose a simplified formula to account for these effects in M 0- A scaling relations for strike-slip earthquakes.
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Lomnitz, Cinna
I was delighted to read Alexander Gusev's opinions on what he calls the “unpredictability paradigm” of earthquakes (Eos, February 10, 1998, p. 71). I always enjoy hearing from a good friend in the pages of Eos. I immediately looked up “paradigm” in my Oxford Dictionary and found this: paradigm n 1) set of all the different forms of a word: verb paradigms. 2) Type of something; pattern; model: a paradigm for others to copy.I wonder whether Sasha Gusev actually believes that branding earthquake prediction a “proven nonscience” [Geller, 1997] is a paradigm for others to copy. As for me, I choose to refrain from climbing on board this particular bandwagon for the following reasons.
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Sekiguchi, H.; Yoshimi, M.; Horikawa, H.
2011-12-01
Broadband ground motions are estimated in the Kanto sedimentary basin which holds Tokyo metropolitan area inside for anticipated great interplate earthquakes along surrounding plate boundaries. Possible scenarios of great earthquakes along Sagami trough are modeled combining characteristic properties of the source area and adequate variation in source parameters in order to evaluate possible ground motion variation due to next Kanto earthquake. South to the rupture area of the 2011 Tohoku earthquake along the Japan trench, we consider possible M8 earthquake. The ground motions are computed with a four-step hybrid technique. We first calculate low-frequency ground motions at the engineering basement. We then calculate higher-frequency ground motions at the same position, and combine the lower- and higher-frequency motions using a matched filter. We finally calculate ground motions at the surface by computing the response of the alluvium-diluvium layers to the combined motions at the engineering basement.
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Operational Earthquake Forecasting: Proposed Guidelines for Implementation (Invited)
Jordan, T. H.
2010-12-01
The goal of operational earthquake forecasting (OEF) is to provide the public with authoritative information about how seismic hazards are changing with time. During periods of high seismic activity, short-term earthquake forecasts based on empirical statistical models can attain nominal probability gains in excess of 100 relative to the long-term forecasts used in probabilistic seismic hazard analysis (PSHA). Prospective experiments are underway by the Collaboratory for the Study of Earthquake Predictability (CSEP) to evaluate the reliability and skill of these seismicity-based forecasts in a variety of tectonic environments. How such information should be used for civil protection is by no means clear, because even with hundredfold increases, the probabilities of large earthquakes typically remain small, rarely exceeding a few percent over forecasting intervals of days or weeks. Civil protection agencies have been understandably cautious in implementing formal procedures for OEF in this sort of “low-probability environment.” Nevertheless, the need to move more quickly towards OEF has been underscored by recent experiences, such as the 2009 L’Aquila earthquake sequence and other seismic crises in which an anxious public has been confused by informal, inconsistent earthquake forecasts. Whether scientists like it or not, rising public expectations for real-time information, accelerated by the use of social media, will require civil protection agencies to develop sources of authoritative information about the short-term earthquake probabilities. In this presentation, I will discuss guidelines for the implementation of OEF informed by my experience on the California Earthquake Prediction Evaluation Council, convened by CalEMA, and the International Commission on Earthquake Forecasting, convened by the Italian government following the L’Aquila disaster. (a) Public sources of information on short-term probabilities should be authoritative, scientific, open, and
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The 2016 Kumamoto earthquake sequence.
Kato, Aitaro; Nakamura, Kouji; Hiyama, Yohei
2016-01-01
Beginning in April 2016, a series of shallow, moderate to large earthquakes with associated strong aftershocks struck the Kumamoto area of Kyushu, SW Japan. An M j 7.3 mainshock occurred on 16 April 2016, close to the epicenter of an M j 6.5 foreshock that occurred about 28 hours earlier. The intense seismicity released the accumulated elastic energy by right-lateral strike slip, mainly along two known, active faults. The mainshock rupture propagated along multiple fault segments with different geometries. The faulting style is reasonably consistent with regional deformation observed on geologic timescales and with the stress field estimated from seismic observations. One striking feature of this sequence is intense seismic activity, including a dynamically triggered earthquake in the Oita region. Following the mainshock rupture, postseismic deformation has been observed, as well as expansion of the seismicity front toward the southwest and northwest.
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The 2016 Kumamoto earthquake sequence
KATO, Aitaro; NAKAMURA, Kouji; HIYAMA, Yohei
2016-01-01
Beginning in April 2016, a series of shallow, moderate to large earthquakes with associated strong aftershocks struck the Kumamoto area of Kyushu, SW Japan. An Mj 7.3 mainshock occurred on 16 April 2016, close to the epicenter of an Mj 6.5 foreshock that occurred about 28 hours earlier. The intense seismicity released the accumulated elastic energy by right-lateral strike slip, mainly along two known, active faults. The mainshock rupture propagated along multiple fault segments with different geometries. The faulting style is reasonably consistent with regional deformation observed on geologic timescales and with the stress field estimated from seismic observations. One striking feature of this sequence is intense seismic activity, including a dynamically triggered earthquake in the Oita region. Following the mainshock rupture, postseismic deformation has been observed, as well as expansion of the seismicity front toward the southwest and northwest. PMID:27725474
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Short-Term Forecasting of Taiwanese Earthquakes Using a Universal Model of Fusion-Fission Processes
Cheong, S.A.; Tan, T.L.; Chen, C.-C.; Chang, W.-L.; Liu, Z.; Chew, L.Y.; Sloot, P.M.A.; Johnson, N.F.
2014-01-01
Predicting how large an earthquake can be, where and when it will strike remains an elusive goal in spite of the ever-increasing volume of data collected by earth scientists. In this paper, we introduce a universal model of fusion-fission processes that can be used to predict earthquakes starting
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Insights into earthquake hazard map performance from shaking history simulations
Stein, S.; Vanneste, K.; Camelbeeck, T.; Vleminckx, B.
2017-12-01
Why recent large earthquakes caused shaking stronger than predicted by earthquake hazard maps is under debate. This issue has two parts. Verification involves how well maps implement probabilistic seismic hazard analysis (PSHA) ("have we built the map right?"). Validation asks how well maps forecast shaking ("have we built the right map?"). We explore how well a map can ideally perform by simulating an area's shaking history and comparing "observed" shaking to that predicted by a map generated for the same parameters. The simulations yield shaking distributions whose mean is consistent with the map, but individual shaking histories show large scatter. Infrequent large earthquakes cause shaking much stronger than mapped, as observed. Hence, PSHA seems internally consistent and can be regarded as verified. Validation is harder because an earthquake history can yield shaking higher or lower than that predicted while being consistent with the hazard map. The scatter decreases for longer observation times because the largest earthquakes and resulting shaking are increasingly likely to have occurred. For the same reason, scatter is much less for the more active plate boundary than for a continental interior. For a continental interior, where the mapped hazard is low, even an M4 event produces exceedances at some sites. Larger earthquakes produce exceedances at more sites. Thus many exceedances result from small earthquakes, but infrequent large ones may cause very large exceedances. However, for a plate boundary, an M6 event produces exceedance at only a few sites, and an M7 produces them in a larger, but still relatively small, portion of the study area. As reality gives only one history, and a real map involves assumptions about more complicated source geometries and occurrence rates, which are unlikely to be exactly correct and thus will contribute additional scatter, it is hard to assess whether misfit between actual shaking and a map — notably higher
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Application and analysis of debris-flow early warning system in Wenchuan earthquake-affected area
Liu, D. L.; Zhang, S. J.; Yang, H. J.; Zhao, L. Q.; Jiang, Y. H.; Tang, D.; Leng, X. P.
2016-02-01
The activities of debris flow (DF) in the Wenchuan earthquake-affected area significantly increased after the earthquake on 12 May 2008. The safety of the lives and property of local people is threatened by DFs. A physics-based early warning system (EWS) for DF forecasting was developed and applied in this earthquake area. This paper introduces an application of the system in the Wenchuan earthquake-affected area and analyzes the prediction results via a comparison to the DF events triggered by the strong rainfall events reported by the local government. The prediction accuracy and efficiency was first compared with a contribution-factor-based system currently used by the weather bureau of Sichuan province. The storm on 17 August 2012 was used as a case study for this comparison. The comparison shows that the false negative rate and false positive rate of the new system is, respectively, 19 and 21 % lower than the system based on the contribution factors. Consequently, the prediction accuracy is obviously higher than the system based on the contribution factors with a higher operational efficiency. On the invitation of the weather bureau of Sichuan province, the authors upgraded their prediction system of DF by using this new system before the monsoon of Wenchuan earthquake-affected area in 2013. Two prediction cases on 9 July 2013 and 10 July 2014 were chosen to further demonstrate that the new EWS has high stability, efficiency, and prediction accuracy.
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The Strain Energy, Seismic Moment and Magnitudes of Large Earthquakes
Purcaru, G.
2004-12-01
The strain energy Est, as potential energy, released by an earthquake and the seismic moment Mo are two fundamental physical earthquake parameters. The earthquake rupture process ``represents'' the release of the accumulated Est. The moment Mo, first obtained in 1966 by Aki, revolutioned the quantification of earthquake size and led to the elimination of the limitations of the conventional magnitudes (originally ML, Richter, 1930) mb, Ms, m, MGR. Both Mo and Est, not in a 1-to-1 correspondence, are uniform measures of the size, although Est is presently less accurate than Mo. Est is partitioned in seismic- (Es), fracture- (Eg) and frictional-energy Ef, and Ef is lost as frictional heat energy. The available Est = Es + Eg (Aki and Richards (1980), Kostrov and Das, (1988) for fundamentals on Mo and Est). Related to Mo, Est and Es, several modern magnitudes were defined under various assumptions: the moment magnitude Mw (Kanamori, 1977), strain energy magnitude ME (Purcaru and Berckhemer, 1978), tsunami magnitude Mt (Abe, 1979), mantle magnitude Mm (Okal and Talandier, 1987), seismic energy magnitude Me (Choy and Boatright, 1995, Yanovskaya et al, 1996), body-wave magnitude Mpw (Tsuboi et al, 1998). The available Est = (1/2μ )Δ σ Mo, Δ σ ~=~average stress drop, and ME is % \\[M_E = 2/3(\\log M_o + \\log(\\Delta\\sigma/\\mu)-12.1) ,\\] % and log Est = 11.8 + 1.5 ME. The estimation of Est was modified to include Mo, Δ and μ of predominant high slip zones (asperities) to account for multiple events (Purcaru, 1997): % \\[E_{st} = \\frac{1}{2} \\sum_i {\\frac{1}{\\mu_i} M_{o,i} \\Delta\\sigma_i} , \\sum_i M_{o,i} = M_o \\] % We derived the energy balance of Est, Es and Eg as: % \\[ E_{st}/M_o = (1+e(g,s)) E_s/M_o , e(g,s) = E_g/E_s \\] % We analyzed a set of about 90 large earthquakes and found that, depending on the goal these magnitudes quantify differently the rupture process, thus providing complementary means of earthquake characterization. Results for some
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An earthquake happens when two blocks of the earth suddenly slip past one another. Earthquakes strike suddenly, violently, and without warning at any time of the day or night. If an earthquake occurs in a populated area, it may cause ...
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Predicting hydrocarbon release from soil
International Nuclear Information System (INIS)
Poppendieck, D.; Loehr, R.C.
2002-01-01
'Full text:' The remediation of hazardous chemicals from soils can be a lengthy and costly process. As a result, recent regulatory initiatives have focused on risk-based corrective action (RBCA) approaches. Such approaches attempt to identify the amount of chemical that can be left at a site with contaminated soil and still be protective of human health and the environment. For hydrocarbons in soils to pose risk to human heath and the environment, the hydrocarbons must be released from the soil and accessible to microorganisms, earthworms, or other higher level organisms. The sorption of hydrocarbons to soil can reduce the availability of the hydrocarbon to receptors. Typically in soils and sediments, there is an initial fast release of a hydrocarbon from the soil to the aqueous phase followed by a slower release of the remaining hydrocarbon to the aqueous phase. The rate and extent of slow release can influence aqueous hydrocarbon concentrations and the fate and transport of hydrocarbons in the subsurface. Once the fast fraction of the chemical has been removed from the soil, the remaining fraction of a chemical may desorb at a rate that natural mechanisms can attenuate the released hydrocarbon. Hence, active remediation may be needed only until the fast fraction has been removed. However, the fast fraction is a soil and chemical specific parameter. This presentation will present a tier I type protocol that has been developed to quickly estimate the fraction of hydrocarbons that are readily released from the soil matrix to the aqueous phase. Previous research in our laboratory and elsewhere has used long-term desorption (four months) studies to determine the readily released fraction. This research shows that a single short-term (less than two weeks) batch extraction procedure provides a good estimate of the fast released fraction derived from long-term experiments. This procedure can be used as a tool to rapidly evaluate the release and bioavailability of
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Development of a Low Cost Earthquake Early Warning System in Taiwan
Wu, Y. M.
2017-12-01
The National Taiwan University (NTU) developed an earthquake early warning (EEW) system for research purposes using low-cost accelerometers (P-Alert) since 2010. As of 2017, a total of 650 stations have been deployed and configured. The NTU system can provide earthquake information within 15 s of an earthquake occurrence. Thus, this system may provide early warnings for cities located more than 50 km from the epicenter. Additionally, the NTU system also has an onsite alert function that triggers a warning for incoming P-waves greater than a certain magnitude threshold, thus providing a 2-3 s lead time before peak ground acceleration (PGA) for regions close to an epicenter. Detailed shaking maps are produced by the NTU system within one or two minutes after an earthquake. Recently, a new module named ShakeAlarm has been developed. Equipped with real-time acceleration signals and the time-dependent anisotropic attenuation relationship of the PGA, ShakingAlarm can provide an accurate PGA estimation immediately before the arrival of the observed PGA. This unique advantage produces sufficient lead time for hazard assessment and emergency response, which is unavailable for traditional shakemap, which are based on only the PGA observed in real time. The performance of ShakingAlarm was tested with six M > 5.5 inland earthquakes from 2013 to 2016. Taking the 2016 M6.4 Meinong earthquake simulation as an example, the predicted PGA converges to a stable value and produces a predicted shake map and an isocontour map of the predicted PGA within 16 seconds of earthquake occurrence. Compared with traditional regional EEW system, ShakingAlarm can effectively identify possible damage regions and provide valuable early warning information (magnitude and PGA) for risk mitigation.
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The Challenge of Centennial Earthquakes to Improve Modern Earthquake Engineering
International Nuclear Information System (INIS)
Saragoni, G. Rodolfo
2008-01-01
The recent commemoration of the centennial of the San Francisco and Valparaiso 1906 earthquakes has given the opportunity to reanalyze their damages from modern earthquake engineering perspective. These two earthquakes plus Messina Reggio Calabria 1908 had a strong impact in the birth and developing of earthquake engineering. The study of the seismic performance of some up today existing buildings, that survive centennial earthquakes, represent a challenge to better understand the limitations of our in use earthquake design methods. Only Valparaiso 1906 earthquake, of the three considered centennial earthquakes, has been repeated again as the Central Chile, 1985, Ms = 7.8 earthquake. In this paper a comparative study of the damage produced by 1906 and 1985 Valparaiso earthquakes is done in the neighborhood of Valparaiso harbor. In this study the only three centennial buildings of 3 stories that survived both earthquakes almost undamaged were identified. Since for 1985 earthquake accelerogram at El Almendral soil conditions as well as in rock were recoded, the vulnerability analysis of these building is done considering instrumental measurements of the demand. The study concludes that good performance of these buildings in the epicentral zone of large earthquakes can not be well explained by modern earthquake engineering methods. Therefore, it is recommended to use in the future of more suitable instrumental parameters, such as the destructiveness potential factor, to describe earthquake demand
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Wang, Pei-Ling; Engelhart, Simon E.; Wang, Kelin; Hawkes, Andrea D.; Horton, Benjamin P.; Nelson, Alan R.; Witter, Robert C.
2013-01-01
Past earthquake rupture models used to explain paleoseismic estimates of coastal subsidence during the great A.D. 1700 Cascadia earthquake have assumed a uniform slip distribution along the megathrust. Here we infer heterogeneous slip for the Cascadia margin in A.D. 1700 that is analogous to slip distributions during instrumentally recorded great subduction earthquakes worldwide. The assumption of uniform distribution in previous rupture models was due partly to the large uncertainties of then available paleoseismic data used to constrain the models. In this work, we use more precise estimates of subsidence in 1700 from detailed tidal microfossil studies. We develop a 3-D elastic dislocation model that allows the slip to vary both along strike and in the dip direction. Despite uncertainties in the updip and downdip slip extensions, the more precise subsidence estimates are best explained by a model with along-strike slip heterogeneity, with multiple patches of high-moment release separated by areas of low-moment release. For example, in A.D. 1700, there was very little slip near Alsea Bay, Oregon (~44.4°N), an area that coincides with a segment boundary previously suggested on the basis of gravity anomalies. A probable subducting seamount in this area may be responsible for impeding rupture during great earthquakes. Our results highlight the need for more precise, high-quality estimates of subsidence or uplift during prehistoric earthquakes from the coasts of southern British Columbia, northern Washington (north of 47°N), southernmost Oregon, and northern California (south of 43°N), where slip distributions of prehistoric earthquakes are poorly constrained.
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The earthquakes of the Baltic shield
International Nuclear Information System (INIS)
Slunga, R.
1990-06-01
More than 200 earthquakes in the Baltic Shield area in the size range ML 0.6-4.5 have been studied by dense regional seismic networks. The analysis includes focal depths, dynamic source parameters, and fault plane solutions. In southern Sweden a long part of the Protogene zone marks a change in the seismic activity. The focal depths indicate three crustal layers: Upper crust (0-18 km in southern Sweden, 0-13 km in northern Sweden), middle crust down to 35 km, and the quiet lower crust. The fault plane solutions show that strike-slip is dominating. Along the Tornquist line significant normal faulting occurs. The stresses released by the earthquakes show a remarkable consistency with a regional principle compression N60W. This indicates that plate-tectonic processes are more important than the land uplift. The spatial distribution is consistent with a model where the earthquakes are breakdowns of asperities on normally stably sliding faults. The aseismic sliding is estimated to be 2000 times more extensive than the seismic sliding. Southern Sweden is estimated to deform horizontally at a rate of 1 mm/year or more. (orig.)
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Tokyo Metropolitan Earthquake Preparedness Project - A Progress Report
Hayashi, H.
2010-12-01
Munich Re once ranked that Tokyo metropolitan region, the capital of Japan, is the most vulnerable area for earthquake disasters, followed by San Francisco Bay Area, US and Osaka, Japan. Seismologists also predict that Tokyo metropolitan region may have at least one near-field earthquake with a probability of 70% for the next 30 years. Given this prediction, Japanese Government took it seriously to conduct damage estimations and revealed that, as the worst case scenario, if a7.3 magnitude earthquake under heavy winds as shown in the fig. 1, it would kill a total of 11,000 people and a total of direct and indirect losses would amount to 112,000,000,000,000 yen(1,300,000,000,000, 1=85yen) . In addition to mortality and financial losses, a total of 25 million people would be severely impacted by this earthquake in four prefectures. If this earthquake occurs, 300,000 elevators will be stopped suddenly, and 12,500 persons would be confined in them for a long time. Seven million people will come to use over 20,000 public shelters spread over the impacted area. Over one millions temporary housing units should be built to accommodate 4.6 million people who lost their dwellings. 2.5 million people will relocate to outside of the damaged area. In short, an unprecedented scale of earthquake disaster is expected and we must prepare for it. Even though disaster mitigation is undoubtedly the best solution, it is more realistic that the expected earthquake would hit before we complete this business. In other words, we must take into account another solution to make the people and the assets in this region more resilient for the Tokyo metropolitan earthquake. This is the question we have been tackling with for the last four years. To increase societal resilience for Tokyo metropolitan earthquake, we adopted a holistic approach to integrate both emergency response and long-term recovery. There are three goals for long-term recovery, which consists of Physical recovery, Economic
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The current situation of the NDL Great East Japan Earthquake Archive 'HINAGIKU'
International Nuclear Information System (INIS)
Suwa, Yasuko
2014-01-01
On March 7, 2013, the National Diet Library (NDL) started full-scale operation of the NDL Great East Japan Earthquake Archive 'HINAGIKU'. Hinagiku is the Searching Portal that enables integrated search and utilization of sound and videos, pictures, websites, etc., about the Great East Japan Earthquake. Its aim is to hand down all records and lessons to future generations and to utilize them for the restoration and reconstruction of the affected areas and for disaster prevention measures. Since its release last year, Hinagiku has been enlarging search targets in cooperation with related institutions. In this article, I will give an overview of the NDL Great East Japan Earthquake Archive and discuss about its challenges for the future. (author)
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Are seismic hazard assessment errors and earthquake surprises unavoidable?
Kossobokov, Vladimir
2013-04-01
Why earthquake occurrences bring us so many surprises? The answer seems evident if we review the relationships that are commonly used to assess seismic hazard. The time-span of physically reliable Seismic History is yet a small portion of a rupture recurrence cycle at an earthquake-prone site, which makes premature any kind of reliable probabilistic statements about narrowly localized seismic hazard. Moreover, seismic evidences accumulated to-date demonstrate clearly that most of the empirical relations commonly accepted in the early history of instrumental seismology can be proved erroneous when testing statistical significance is applied. Seismic events, including mega-earthquakes, cluster displaying behaviors that are far from independent or periodic. Their distribution in space is possibly fractal, definitely, far from uniform even in a single segment of a fault zone. Such a situation contradicts generally accepted assumptions used for analytically tractable or computer simulations and complicates design of reliable methodologies for realistic earthquake hazard assessment, as well as search and definition of precursory behaviors to be used for forecast/prediction purposes. As a result, the conclusions drawn from such simulations and analyses can MISLEAD TO SCIENTIFICALLY GROUNDLESS APPLICATION, which is unwise and extremely dangerous in assessing expected societal risks and losses. For example, a systematic comparison of the GSHAP peak ground acceleration estimates with those related to actual strong earthquakes, unfortunately, discloses gross inadequacy of this "probabilistic" product, which appears UNACCEPTABLE FOR ANY KIND OF RESPONSIBLE SEISMIC RISK EVALUATION AND KNOWLEDGEABLE DISASTER PREVENTION. The self-evident shortcomings and failures of GSHAP appeals to all earthquake scientists and engineers for an urgent revision of the global seismic hazard maps from the first principles including background methodologies involved, such that there becomes: (a) a
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Directory of Open Access Journals (Sweden)
S. Cht. Mavrodiev
2004-01-01
Full Text Available The local 'when' for earthquake prediction is based on the connection between geomagnetic 'quakes' and the next incoming minimum or maximum of tidal gravitational potential. The probability time window for the predicted earthquake is for the tidal minimum approximately ±1 day and for the maximum ±2 days. The preliminary statistic estimation on the basis of distribution of the time difference between occurred and predicted earthquakes for the period 2002-2003 for the Sofia region is given. The possibility for creating a local 'when, where' earthquake research and prediction NETWORK is based on the accurate monitoring of the electromagnetic field with special space and time scales under, on and over the Earth's surface. The periodically upgraded information from seismic hazard maps and other standard geodetic information, as well as other precursory information, is essential.
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e-Science on Earthquake Disaster Mitigation by EUAsiaGrid
Yen, Eric; Lin, Simon; Chen, Hsin-Yen; Chao, Li; Huang, Bor-Shoh; Liang, Wen-Tzong
2010-05-01
Although earthquake is not predictable at this moment, with the aid of accurate seismic wave propagation analysis, we could simulate the potential hazards at all distances from possible fault sources by understanding the source rupture process during large earthquakes. With the integration of strong ground-motion sensor network, earthquake data center and seismic wave propagation analysis over gLite e-Science Infrastructure, we could explore much better knowledge on the impact and vulnerability of potential earthquake hazards. On the other hand, this application also demonstrated the e-Science way to investigate unknown earth structure. Regional integration of earthquake sensor networks could aid in fast event reporting and accurate event data collection. Federation of earthquake data center entails consolidation and sharing of seismology and geology knowledge. Capability building of seismic wave propagation analysis implies the predictability of potential hazard impacts. With gLite infrastructure and EUAsiaGrid collaboration framework, earth scientists from Taiwan, Vietnam, Philippine, Thailand are working together to alleviate potential seismic threats by making use of Grid technologies and also to support seismology researches by e-Science. A cross continental e-infrastructure, based on EGEE and EUAsiaGrid, is established for seismic wave forward simulation and risk estimation. Both the computing challenge on seismic wave analysis among 5 European and Asian partners, and the data challenge for data center federation had been exercised and verified. Seismogram-on-Demand service is also developed for the automatic generation of seismogram on any sensor point to a specific epicenter. To ease the access to all the services based on users workflow and retain the maximal flexibility, a Seismology Science Gateway integating data, computation, workflow, services and user communities would be implemented based on typical use cases. In the future, extension of the
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Estimation of Natural Frequencies During Earthquakes
DEFF Research Database (Denmark)
Kirkegaard, Poul Henning; Rytter, A
1997-01-01
This paper presents two different recursive prediction error method (RPEM} implementations of multivariate Auto-Regressive Moving- Average (ARMAV) models for identification of a time variant civil engineering structure subject to an earthquake. The two techniques are tested on measurements made...
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Tao, Wei; Shen, Zheng-Kang; Zhang, Yong
2016-04-01
concentration areas in the model, one is located in the mid and upper crust on the hanging wall where the strain energy could be released by permanent deformation like folding, and the other lies in the deep part of the fault where the strain energy could be released by earthquakes. (5) The whole earthquake dynamic process could be clearly reflected by the evolutions of the strain energy increments on the stages of the earthquake cycle. In the inter-seismic period, the strain energy accumulates relatively slowly; prior to the earthquake, the fault is locking and the strain energy accumulates fast, and some of the strain energy is released on the upper crust on the hanging wall of the fault. In coseismic stage, the strain energy is released fast along the fault. In the poseismic stage, the slow accumulation process of strain recovers rapidly as that in the inerseismic period in around one hundred years. The simulation study in this thesis would help better understand the earthquake dynamic process.
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Stein, Seth; Liu, Mian; Luo, Gang; Wang, Hui
2014-05-01
Earthquakes in midcontinents and those at plate boundaries behave quite differently in space and time, owing to the geometry of faults and the rate at which they are loaded. Faults at plate boundaries are loaded at constant rates by steady relative plate motion. Consequently, earthquakes concentrate along the plate boundary faults, and show quasi-periodic occurrences, although the actual temporal patterns are often complicated. However, in midcontinents, the tectonic loading is shared by a complex system of interacting faults spread over a large region, such that a large earthquake on one fault could increase the loading rates on remote faults in the system. Because the low tectonic loading rate is shared by many faults in midcontinents, individual faults may remain dormant for a long time and then become active for a short period. The resulting earthquakes are therefore episodic and spatially migrating. These effects can be seen in many areas, with a prime example being a 2000-year record from North China, which shows migration of large earthquakes between fault systems spread over a large region such that no large earthquakes rupture the same fault segment twice. Because seismic activity within mid-continents is usually much lower than that along plate boundary zones, even small earthquakes can cause widespread concerns, especially when these events occur in the source regions of previous large earthquakes. However, these small earthquakes may be aftershocks that continue for decades or even longer, because aftershock sequences often last much longer in midcontinents where tectonic loading is slow, than at plate boundaries. The recent seismicity in the Tangshan region in North China is likely aftershocks of the 1976 M7.8 Tangshan earthquake. Similarly, current seismicity in the New Madrid seismic zone in central U.S. appears to be aftershocks of a cluster of M ~7.0 events in 1811-1812. These large events and similar events in the past millennium release strain
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Uncertainty estimates for predictions of the impact of breeder-reactor radionuclide releases
International Nuclear Information System (INIS)
Miller, C.W.; Little, C.A.
1982-01-01
This paper summarizes estimates, compiled in a larger report, of the uncertainty associated with models and parameters used to assess the impact on man radionuclide releases to the environment by breeder reactor facilities. These estimates indicate that, for many sites, generic models and representative parameter values may reasonably be used to calculate doses from annual average radionuclide releases when these calculated doses are on the order of one-tenth or less of a relevant dose limit. For short-term, accidental releases, the uncertainty in the dose calculations may be much larger than an order of magnitude. As a result, it may be necessary to incorporate site-specific information into the dose calculation under such circumstances. However, even using site-specific information, inherent natural variability within human receptors, and the uncertainties in the dose conversion factor will likely result in an overall uncertainty of greater than an order of magnitude for predictions of dose following short-term releases
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Nurse willingness to report for work in the event of an earthquake in Israel.
Ben Natan, Merav; Nigel, Simon; Yevdayev, Innush; Qadan, Mohamad; Dudkiewicz, Mickey
2014-10-01
To examine variables affecting nurse willingness to report for work in the event of an earthquake in Israel and whether this can be predicted through the Theory of Self-Efficacy. The nursing profession has a major role in preparing for earthquakes. Nurse willingness to report to work in the event of an earthquake has never before been examined. Self-administered questionnaires were distributed among a convenience sample of 400 nurses and nursing students in Israel during January-April 2012. High willingness to report to work in the event of an earthquake was declared by 57% of respondents. High perceived self-efficacy, level of knowledge and experience predict willingness to report to work in the event of an earthquake. Multidisciplinary collaboration and support was also cited as a meaningful factor. Perceived self-efficacy, level of knowledge, experience and the support of a multidisciplinary staff affect nurse willingness to report to work in the event of an earthquake. Nurse managers can identify factors that increase nurse willingness to report to work in the event of an earthquake and consequently develop strategies for more efficient management of their nursing workforce. © 2013 John Wiley & Sons Ltd.
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Experimental Study of Thermal Field Evolution in the Short-Impending Stage Before Earthquakes
Ren, Yaqiong; Ma, Jin; Liu, Peixun; Chen, Shunyun
2017-08-01
Phenomena at critical points are vital for identifying the short-impending stage prior to earthquakes. The peak stress is a critical point when stress is converted from predominantly accumulation to predominantly release. We call the duration between the peak stress and instability "the meta-instability stage", which refers to the short-impending stage of earthquakes. The meta-instability stage consists of a steady releasing quasi-static stage and an accelerated releasing quasi-dynamic stage. The turning point of the above two stages is the remaining critical point. To identify the two critical points in the field, it is necessary to study the characteristic phenomena of various physical fields in the meta-instability stage in the laboratory, and the strain and displacement variations were studied. Considering that stress and relative displacement can be detected by thermal variations and peculiarities in the full-field observations, we employed a cooled thermal infrared imaging system to record thermal variations in the meta-instability stage of stick slip events generated along a simulated, precut planer strike slip fault in a granodiorite block on a horizontally bilateral servo-controlled press machine. The experimental results demonstrate the following: (1) a large area of decreasing temperatures in wall rocks and increasing temperatures in sporadic sections of the fault indicate entrance into the meta-instability stage. (2) The rapid expansion of regions of increasing temperatures on the fault and the enhancement of temperature increase amplitude correspond to the turning point from the quasi-static stage to the quasi-dynamic stage. Our results reveal thermal indicators for the critical points prior to earthquakes that provide clues for identifying the short-impending stage of earthquakes.
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Our response to the earthquake at Onagawa Nuclear Power Station
International Nuclear Information System (INIS)
Hirakawa, Tomoshi
2008-01-01
When the Miyagi Offshore earthquake occurred on August 16, 2005, all three units at the Onagawa NPS were shut down automatically according to the Strong Seismic Acceleration' signal. Our inspection after the earthquake confirmed there was no damage to the equipment of the nuclear power plants, but the analysis of the response spectrum observed at the bedrock showed the earthquake had exceeded the 'design-basis earthquake', at certain periods, so that we implemented a review of the seismic safety of plant facilities. In the review, the ground motion of Miyagi Offshore Earthquake which are predicted to occur in the near future were reexamined based on the observation data, and then 'The Ground Motion for Safety Check' surpassing the supposed ground motion of the largest earthquake was established. The seismic safety of plant facilities, important for safety, was assured. At present, No.1 to No.3 units at Onagawa NPS have returned to normal operation. (author)
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Ghani, Kay Dora Abd.; Tukiar, Mohd Azuan; Hamid, Nor Hayati Abdul
2017-08-01
Malaysia is surrounded by the tectonic feature of the Sumatera area which consists of two seismically active inter-plate boundaries, namely the Indo-Australian and the Eurasian Plates on the west and the Philippine Plates on the east. Hence, Malaysia experiences tremors from far distant earthquake occurring in Banda Aceh, Nias Island, Padang and other parts of Sumatera Indonesia. In order to predict the safety of precast buildings in Malaysia under near field ground motion the response spectrum analysis could be used for dealing with future earthquake whose specific nature is unknown. This paper aimed to develop of capacity demand response spectrum subject to Design Basis Earthquake (DBE) and Maximum Considered Earthquake (MCE) in order to assess the performance of precast beam column joint. From the capacity-demand response spectrum analysis, it can be concluded that the precast beam-column joints would not survive when subjected to earthquake excitation with surface-wave magnitude, Mw, of more than 5.5 Scale Richter (Type 1 spectra). This means that the beam-column joint which was designed using the current code of practice (BS8110) would be severely damaged when subjected to high earthquake excitation. The capacity-demand response spectrum analysis also shows that the precast beam-column joints in the prototype studied would be severely damaged when subjected to Maximum Considered Earthquake (MCE) with PGA=0.22g having a surface-wave magnitude of more than 5.5 Scale Richter, or Type 1 spectra.
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Ionospheric precursors to large earthquakes: A case study of the 2011 Japanese Tohoku Earthquake
Carter, B. A.; Kellerman, A. C.; Kane, T. A.; Dyson, P. L.; Norman, R.; Zhang, K.
2013-09-01
Researchers have reported ionospheric electron distribution abnormalities, such as electron density enhancements and/or depletions, that they claimed were related to forthcoming earthquakes. In this study, the Tohoku earthquake is examined using ionosonde data to establish whether any otherwise unexplained ionospheric anomalies were detected in the days and hours prior to the event. As the choices for the ionospheric baseline are generally different between previous works, three separate baselines for the peak plasma frequency of the F2 layer, foF2, are employed here; the running 30-day median (commonly used in other works), the International Reference Ionosphere (IRI) model and the Thermosphere Ionosphere Electrodynamic General Circulation Model (TIE-GCM). It is demonstrated that the classification of an ionospheric perturbation is heavily reliant on the baseline used, with the 30-day median, the IRI and the TIE-GCM generally underestimating, approximately describing and overestimating the measured foF2, respectively, in the 1-month period leading up to the earthquake. A detailed analysis of the ionospheric variability in the 3 days before the earthquake is then undertaken, where a simultaneous increase in foF2 and the Es layer peak plasma frequency, foEs, relative to the 30-day median was observed within 1 h before the earthquake. A statistical search for similar simultaneous foF2 and foEs increases in 6 years of data revealed that this feature has been observed on many other occasions without related seismic activity. Therefore, it is concluded that one cannot confidently use this type of ionospheric perturbation to predict an impending earthquake. It is suggested that in order to achieve significant progress in our understanding of seismo-ionospheric coupling, better account must be taken of other known sources of ionospheric variability in addition to solar and geomagnetic activity, such as the thermospheric coupling.
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Characteristics of Earthquake Ground Motion Attenuation in Korea and Japan
International Nuclear Information System (INIS)
Choi, In-Kil; Choun, Young-Sun; Nakajima, Masato; Ohtori, Yasuki; Yun, Kwan-Hee
2006-01-01
The characteristics of a ground motion attenuation in Korea and Japan were estimated by using the earthquake ground motions recorded at the equal distance observation station by KMA, K-NET and KiK-net of Korea and Japan. The ground motion attenuation equations proposed for Korea and Japan were evaluated by comparing the predicted value for the Fukuoka earthquake with the observed records. The predicted values from the attenuation equations show a good agreement with the observed records and each other. It can be concluded from this study that the ground motion attenuation equations can be used for the prediction of strong ground motion attenuation and for an evaluation of the attenuation equations proposed for Korea
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Impact-based earthquake alerts with the U.S. Geological Survey's PAGER system: what's next?
Wald, D.J.; Jaiswal, K.S.; Marano, K.D.; Garcia, D.; So, E.; Hearne, M.
2012-01-01
In September 2010, the USGS began publicly releasing earthquake alerts for significant earthquakes around the globe based on estimates of potential casualties and economic losses with its Prompt Assessment of Global Earthquakes for Response (PAGER) system. These estimates significantly enhanced the utility of the USGS PAGER system which had been, since 2006, providing estimated population exposures to specific shaking intensities. Quantifying earthquake impacts and communicating estimated losses (and their uncertainties) to the public, the media, humanitarian, and response communities required a new protocol—necessitating the development of an Earthquake Impact Scale—described herein and now deployed with the PAGER system. After two years of PAGER-based impact alerting, we now review operations, hazard calculations, loss models, alerting protocols, and our success rate for recent (2010-2011) events. This review prompts analyses of the strengths, limitations, opportunities, and pressures, allowing clearer definition of future research and development priorities for the PAGER system.
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Predictors of psychological resilience amongst medical students following major earthquakes.
Carter, Frances; Bell, Caroline; Ali, Anthony; McKenzie, Janice; Boden, Joseph M; Wilkinson, Timothy; Bell, Caroline
2016-05-06
To identify predictors of self-reported psychological resilience amongst medical students following major earthquakes in Canterbury in 2010 and 2011. Two hundred and fifty-three medical students from the Christchurch campus, University of Otago, were invited to participate in an electronic survey seven months following the most severe earthquake. Students completed the Connor-Davidson Resilience Scale, the Depression, Anxiety and Stress Scale, the Post-traumatic Disorder Checklist, the Work and Adjustment Scale, and the Eysenck Personality Questionnaire. Likert scales and other questions were also used to assess a range of variables including demographic and historical variables (eg, self-rated resilience prior to the earthquakes), plus the impacts of the earthquakes. The response rate was 78%. Univariate analyses identified multiple variables that were significantly associated with higher resilience. Multiple linear regression analyses produced a fitted model that was able to explain 35% of the variance in resilience scores. The best predictors of higher resilience were: retrospectively-rated personality prior to the earthquakes (higher extroversion and lower neuroticism); higher self-rated resilience prior to the earthquakes; not being exposed to the most severe earthquake; and less psychological distress following the earthquakes. Psychological resilience amongst medical students following major earthquakes was able to be predicted to a moderate extent.
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Bodin, Paul; Gomberg, Joan
1994-01-01
This article presents evidence for the channeling of strain energy released by the Ms = 7.4 Landers, California, earthquake within the eastern California shear zone (ECSZ). We document an increase in seismicity levels during the 22-hr period starting with the Landers earthquake and culminating 22 hr later with the Ms = 5.4 Little Skull Mountain (LSM), Nevada, earthquake. We evaluate the completeness of regional seismicity catalogs during this period and find that the continuity of post-Landers strain release within the ECSZ is even more pronounced than is evident from the catalog data. We hypothesize that regional-scale connectivity of faults within the ECSZ and LSM region is a critical ingredient in the unprecedented scale and distribution of remotely triggered earthquakes and geodetically manifest strain changes that followed the Landers earthquake. The viability of static strain changes as triggering agents is tested using numerical models. Modeling results illustrate that regional-scale fault connectivity can increase the static strain changes by approximately an order of magnitude at distances of at least 280 km, the distance between the Landers and LSM epicenters. This is possible for models that include both a network of connected faults that slip “sympathetically” and realistic levels of tectonic prestrain. Alternatively, if dynamic strains are a more significant triggering agent than static strains, ECSZ structure may still be important in determining the distribution of triggered seismic and aseismic deformation.
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Teleseismic analysis of the 1990 and 1991 earthquakes near Potenza
Directory of Open Access Journals (Sweden)
G. Ekstrom
1994-06-01
Full Text Available Analysis of the available teleseismic data for two moderate earthquakes near the town of Potenza in the Southern Apennines shows that both involve strike-slip faulting on a plane oriented approximately east-west. Only the larger, 5 May 1990, earthquake is sufficiently large for analysis by conventional teleseismic waveform inversion methods, and is seen to consist of a foreshock followed 11 seconds later by the main release of moment. The focal mechanism and seismic moment of the 26 May 1991 earthquake is determined by quantitative comparison of its 15-60 s period surface waves with those generated by the 5 May 1990 event. The focal mechanisms for the two events are found to be very similar. The 1991 earthquake has a scalar moment that is approximately 18% that of the 1990 mainshock. Comparison of higher frequency P waves for the two events, recorded at regional distance, shows that the ratio of trace amplitudes is smaller than the ratio of scalar moments, suggesting that the stress drop for the 1991 event is distinctly smaller than for the 1990 mainshock.
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Earthquake early warning using P-waves that appear after initial S-waves
Kodera, Y.
2017-12-01
As measures for underprediction for large earthquakes with finite faults and overprediction for multiple simultaneous earthquakes, Hoshiba (2013), Hoshiba and Aoki (2015), and Kodera et al. (2016) proposed earthquake early warning (EEW) methods that directly predict ground motion by computing the wave propagation of observed ground motion. These methods are expected to predict ground motion with a high accuracy even for complicated scenarios because these methods do not need source parameter estimation. On the other hand, there is room for improvement in their rapidity because they predict strong motion prediction mainly based on the observation of S-waves and do not explicitly use P-wave information available before the S-waves. In this research, we propose a real-time P-wave detector to incorporate P-wave information into these wavefield-estimation approaches. P-waves within a few seconds from the P-onsets are commonly used in many existing EEW methods. In addition, we focus on P-waves that may appear in the later part of seismic waves. Kurahashi and Irikura (2013) mentioned that P-waves radiated from strong motion generation areas (SMGAs) were recognizable after S-waves of the initial rupture point in the 2011 off the Pacific coast of Tohoku earthquake (Mw 9.0) (the Tohoku-oki earthquake). Detecting these P-waves would enhance the rapidity of prediction for the peak ground motion generated by SMGAs. We constructed a real-time P-wave detector that uses a polarity analysis. Using acceleration records in boreholes of KiK-net (band-pass filtered around 0.5-10 Hz with site amplification correction), the P-wave detector performed the principal component analysis with a sliding window of 4 s and calculated P-filter values (e.g. Ross and Ben-Zion, 2014). The application to the Tohoku-oki earthquake (Mw 9.0) showed that (1) peaks of P-filter that corresponded to SMGAs appeared in several stations located near SMGAs and (2) real-time seismic intensities (Kunugi et al
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Prospective testing of Coulomb short-term earthquake forecasts
Jackson, D. D.; Kagan, Y. Y.; Schorlemmer, D.; Zechar, J. D.; Wang, Q.; Wong, K.
2009-12-01
Earthquake induced Coulomb stresses, whether static or dynamic, suddenly change the probability of future earthquakes. Models to estimate stress and the resulting seismicity changes could help to illuminate earthquake physics and guide appropriate precautionary response. But do these models have improved forecasting power compared to empirical statistical models? The best answer lies in prospective testing in which a fully specified model, with no subsequent parameter adjustments, is evaluated against future earthquakes. The Center of Study of Earthquake Predictability (CSEP) facilitates such prospective testing of earthquake forecasts, including several short term forecasts. Formulating Coulomb stress models for formal testing involves several practical problems, mostly shared with other short-term models. First, earthquake probabilities must be calculated after each “perpetrator” earthquake but before the triggered earthquakes, or “victims”. The time interval between a perpetrator and its victims may be very short, as characterized by the Omori law for aftershocks. CSEP evaluates short term models daily, and allows daily updates of the models. However, lots can happen in a day. An alternative is to test and update models on the occurrence of each earthquake over a certain magnitude. To make such updates rapidly enough and to qualify as prospective, earthquake focal mechanisms, slip distributions, stress patterns, and earthquake probabilities would have to be made by computer without human intervention. This scheme would be more appropriate for evaluating scientific ideas, but it may be less useful for practical applications than daily updates. Second, triggered earthquakes are imperfectly recorded following larger events because their seismic waves are buried in the coda of the earlier event. To solve this problem, testing methods need to allow for “censoring” of early aftershock data, and a quantitative model for detection threshold as a function of
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Earthquake precursory events around epicenters and local active faults
Valizadeh Alvan, H.; Mansor, S. B.; Haydari Azad, F.
2013-05-01
The chain of underground events which are triggered by seismic activities and physical/chemical interactions prior to a shake in the earth's crust may produce surface and above surface phenomena. During the past decades many researchers have been carried away to seek the possibility of short term earthquake prediction using remote sensing data. Currently, there are several theories about the preparation stages of earthquakes most of which stress on raises in heat and seismic waves as the main signs of an impending earthquakes. Their differences only lie in the secondary phenomena which are triggered by these events. In any case, with the recent advances in remote sensing sensors and techniques now we are able to provide wider, more accurate monitoring of land, ocean and atmosphere. Among all theoretical factors, changes in Surface Latent Heat Flux (SLHF), Sea & Land Surface Temperature (SST & LST) and surface chlorophyll-a are easier to record from earth observing satellites. SLHF is the amount of energy exchange in the form of water vapor between the earth's surface and atmosphere. Abnormal variations in this factor have been frequently reported as an earthquake precursor during the past years. The accumulated stress in the earth's crust during the preparation phase of earthquakes is said to be the main cause of temperature anomalies weeks to days before the main event and subsequent shakes. Chemical and physical interactions in the presence of underground water lead to higher water evaporation prior to inland earthquakes. In case of oceanic earthquakes, higher temperature at the ocean beds may lead to higher amount of Chl-a on the sea surface. On the other hand, it has been also said that the leak of Radon gas which occurs as rocks break during earthquake preparation causes the formation of airborne ions and higher Air Temperature (AT). We have chosen to perform a statistical, long-term, and short-term approach by considering the reoccurrence intervals of past
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THE GREAT SOUTHERN CALIFORNIA SHAKEOUT: Earthquake Science for 22 Million People
Jones, L.; Cox, D.; Perry, S.; Hudnut, K.; Benthien, M.; Bwarie, J.; Vinci, M.; Buchanan, M.; Long, K.; Sinha, S.; Collins, L.
2008-12-01
Earthquake science is being communicated to and used by the 22 million residents of southern California to improve resiliency to future earthquakes through the Great Southern California ShakeOut. The ShakeOut began when the USGS partnered with the California Geological Survey, Southern California Earthquake Center and many other organizations to bring 300 scientists and engineers together to formulate a comprehensive description of a plausible major earthquake, released in May 2008, as the ShakeOut Scenario, a description of the impacts and consequences of a M7.8 earthquake on the Southern San Andreas Fault (USGS OFR2008-1150). The Great Southern California ShakeOut was a week of special events featuring the largest earthquake drill in United States history. The ShakeOut drill occurred in houses, businesses, and public spaces throughout southern California at 10AM on November 13, 2008, when southern Californians were asked to pretend that the M7.8 scenario earthquake had occurred and to practice actions that could reduce the impact on their lives. Residents, organizations, schools and businesses registered to participate in the drill through www.shakeout.org where they could get accessible information about the scenario earthquake and share ideas for better reparation. As of September 8, 2008, over 2.7 million confirmed participants had been registered. The primary message of the ShakeOut is that what we do now, before a big earthquake, will determine what our lives will be like after. The goal of the ShakeOut has been to change the culture of earthquake preparedness in southern California, making earthquakes a reality that are regularly discussed. This implements the sociological finding that 'milling,' discussing a problem with loved ones, is a prerequisite to taking action. ShakeOut milling is taking place at all levels from individuals and families, to corporations and governments. Actions taken as a result of the ShakeOut include the adoption of earthquake
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Geoethical suggestions for reducing risk of next (not only strong) earthquakes
Nemec, Vaclav
2013-04-01
Three relatively recent examples of earthquakes can be used as a background for suggesting geoethical views into any prediction accompanied by a risk analysis. ĹAquila earthquake (Italy - 2009): ĹAquila was largely destroyed by earthquakes in 1315, 1319, 1452, 1461, 1501, 1646, 1703 (until that time altogether about 3000 victims) and 1786 (about 6000 victims of this event only). The city was rebuilt and remained stable until October 2008, when tremors began again. From January 1 through April 5, 2009, additional 304 tremors were reported. When after measuring increased levels of radon emitted from the ground a local citizen (for many years working for the Italian National Institute of Astrophysics) predicted a major earthquake on Italian television, he was accused of being alarmist. Italy's National Commission for Prediction and Prevention of Major Risks met in L'Aquila for one hour on March 31, 2009, without really evaluating and characterising the risks that were present. On April 6 a 6.3 magnitude earthquake struck Aquila and nearby towns, killing 309 people and injuring more than 1,500. The quake also destroyed roughly 20,000 buildings, temporarily displacing another 65,000 people. In July 2010, prosecutor Fabio Picuti charged the Commission members with manslaughter and negligence for failing to warn the public of the impending risk. Many international organizations joined the chorus of criticism wrongly interpreting the accusation and sentence at the first stage as a problem of impossibility to predict earthquakes. - The Eyjafjallajokull volcano eruption (Iceland - 2010) is a reminder that in our globalized, interconnected world because of the increased sensibility of the new technology even a relatively small natural disaster may cause unexpected range of problems. - Earthquake and tsunami (Japan - 2011) - the most powerful known earthquake ever to have hit Japan on March 11. Whereas the proper earthquake with the magnitude of 9.0 has caused minimum of
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Strong ground motion of the 2016 Kumamoto earthquake
Aoi, S.; Kunugi, T.; Suzuki, W.; Kubo, H.; Morikawa, N.; Fujiwara, H.
2016-12-01
The 2016 Kumamoto earthquake that is composed of Mw 6.1 and Mw 7.1 earthquakes respectively occurred in the Kumamoto region at 21:26 on April 14 and 28 hours later at 1:25 on April 16, 2016 (JST). These earthquakes are considered to rupture mainly the Hinagu fault zone for the Mw 6.1 event and the Futagawa fault zone for the Mw 7.1 event, respectively, where the Headquarter for Earthquake Research Promotion performed the long-term evaluation as well as seismic hazard assessment prior to the 2016 Kumamoto earthquake. Strong shakings with seismic intensity 7 in the JMA scale were observed at four times in total: Mashiki town for the Mw 6.1 and Mw 7.1 events, Nishihara village for the Mw 7.1 event, and NIED/KiK-net Mashiki (KMMH16) for the Mw 7.1 event. KiK-net Mashiki (KMMH16) recorded peak ground acceleration more than 1000 cm/s/s, and Nishihara village recorded peak ground velocity more than 250 cm/s. Ground motions were observed wider area for the Mw 7.1 event than the Mw 6.1 event. Peak ground accelerations and peak ground velocities of K-NET/KiK-net stations are consistent with the ground motion prediction equations by Si and Midorikawa (1999). Peak ground velocities at longer distance than 200 km attenuate slowly, which can be attributed to the large Love wave with a dominant period around 10 seconds. 5%-damped pseudo spectral velocity of the Mashiki town shows a peak at period of 1-2 s that exceeds ground motion response of JR Takatori of the 1995 Kobe earthquake and the Kawaguchi town of the 2004 Chuetsu earthquake. 5%-damped pseudo spectral velocity of the Nishihara village shows 350 cm/s peak at period of 3-4 s that is similar to the several stations in Kathmandu basin by Takai et al. (2016) during the 2015 Gorkha earthquake in Nepal. Ground motions at several stations in Oita exceed the ground motion prediction equations due to an earthquake induced by the Mw 7.1 event. Peak ground accelerations of K-NET Yufuin (OIT009) records 90 cm/s/s for the Mw 7
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Konstantaras, Anthony; Katsifarakis, Emmanouil; Artzouxaltzis, Xristos; Makris, John; Vallianatos, Filippos; Varley, Martin
2010-05-01
This paper is a preliminary investigation of the possible correlation of temporal and energy release patterns of seismic activity involving the preparation processes of consecutive sizeable seismic events [1,2]. The background idea is that during periods of low-level seismic activity, stress processes in the crust accumulate energy at the seismogenic area whilst larger seismic events act as a decongesting mechanism releasing considerable energy [3,4]. A dynamic algorithm is being developed aiming to identify and cluster pre- and post- seismic events to the main earthquake following on research carried out by Zubkov [5] and Dobrovolsky [6,7]. This clustering technique along with energy release equations dependent on Richter's scale [8,9] allow for an estimate to be drawn regarding the amount of the energy being released by the seismic sequence. The above approach is being implemented as a monitoring tool to investigate the behaviour of the underlying energy management system by introducing this information to various neural [10,11] and soft computing models [1,12,13,14]. The incorporation of intelligent systems aims towards the detection and simulation of the possible relationship between energy release patterns and time-intervals among consecutive sizeable earthquakes [1,15]. Anticipated successful training of the imported intelligent systems may result in a real-time, on-line processing methodology [1,16] capable to dynamically approximate the time-interval between the latest and the next forthcoming sizeable seismic event by monitoring the energy release process in a specific seismogenic area. Indexing terms: pattern recognition, long-term earthquake precursors, neural networks, soft computing, earthquake occurrence intervals References [1] Konstantaras A., Vallianatos F., Varley M.R. and Makris J. P.: ‘Soft computing modelling of seismicity in the southern Hellenic arc', IEEE Geoscience and Remote Sensing Letters, vol. 5 (3), pp. 323-327, 2008 [2] Eneva M. and
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Aspect of the 2011 off the Pacific coast Tohoku Earthquake, Japan
International Nuclear Information System (INIS)
Kato, Aitaro
2012-01-01
The 2011 off the Pacific coast of Tohoku Earthquake (Tohoku-Oki), Japan, was the first magnitude (M) 9 subduction megathrust event to be recorded by a dense network of seismic, geodetic, and tsunami observations. I here review the Tohoku-Oki earthquake in terms of, 1) asperity model, 2) earthquake source observations, 3) precedent processes, 4) postseismic slip (afetrslip). Based on finite source models of the Tohoku-Oki mainshock, the coseismic fault slip exceeded 30 m at shallow part of the subduction zone off-shore of Miyagi. The rupture reached the trench axis, producing a large uplift therein, which was likely an important factor generating devastating tsunami waves. The mainshock was preceded by slow-slip transients propagating toward the initial rupture point, which may have caused substantial stress loading, prompting the unstable dynamic rupture of the mainshock. Furthermore, a sequence of M 7-class interplate earthquakes and subsequent large afterslip events, those occurred before the mainshock rupture, might be interpreted as preparation stage of the earthquake generation. Most of slip released by the postseismic deformation following the Tohoku-Oki mainshock is located in the region peripheral to the large coseismic slip area. (author)
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Stress drops of induced and tectonic earthquakes in the central United States are indistinguishable.
Huang, Yihe; Ellsworth, William L; Beroza, Gregory C
2017-08-01
Induced earthquakes currently pose a significant hazard in the central United States, but there is considerable uncertainty about the severity of their ground motions. We measure stress drops of 39 moderate-magnitude induced and tectonic earthquakes in the central United States and eastern North America. Induced earthquakes, more than half of which are shallower than 5 km, show a comparable median stress drop to tectonic earthquakes in the central United States that are dominantly strike-slip but a lower median stress drop than that of tectonic earthquakes in the eastern North America that are dominantly reverse-faulting. This suggests that ground motion prediction equations developed for tectonic earthquakes can be applied to induced earthquakes if the effects of depth and faulting style are properly considered. Our observation leads to the notion that, similar to tectonic earthquakes, induced earthquakes are driven by tectonic stresses.
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International Nuclear Information System (INIS)
Day, S.A.
1989-01-01
An analysis to determine the risk associated with earthquakes at the Rocky Flats Plant was performed. Seismic analyses and structural evaluations were used to postulate building and equipment damage and radiological releases to the environment from various magnitudes of earthquakes. Dispersion modeling and dose assessment to the public were then calculated. The frequency of occurrence of various magnitudes of earthquakes were determined from the Department of Energy natural Phenomena Hazards Modeling Project. Risk to the public was probabilistically assessed for each magnitude of earthquake and for overall seismic risk. Based on the results of this Probabilistic Risk Assessment and a cost/benefit analysis, seismic upgrades are being implemented for several plutonium-handling facilities for the purpose of risk reduction
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Yamada, M.; Mori, J. J.
2011-12-01
The 2011 off the Pacific Coast of Tohoku Earthquake (Mw9.0) caused significant damage over a large area of northeastern Honshu. An earthquake early warning was issued to the public in the Tohoku region about 8 seconds after the first P-arrival, which is 31 seconds after the origin time. There was no 'blind zone', and warnings were received at all locations before S-wave arrivals, since the earthquake was fairly far offshore. Although the early warning message was properly reported in Tohoku region which was the most severely affected area, a message was not sent to the more distant Tokyo region because the intensity was underestimated. . This underestimation was because the magnitude determination in the first few seconds was relatively small (Mj8.1)., and there was no consideration of a finite fault with a long length. Another significant issue is that warnings were sometimes not properly provided for aftershocks. Immediately following the earthquake, the waveforms of some large aftershocks were contaminated by long-period surface waves from the mainshock, which made it difficult to pick P-wave arrivals. Also, correctly distinguishing and locating later aftershocks was sometimes difficult, when multiple events occurred within a short period of time. This masinhock begins with relatively small moment release for the first 10 s . Since the amplitude of the initial waveforms is small, most methods that use amplitudes and periods of the P-wave (e.g. Wu and Kanamori, 2005) cannot correctly determine the size of the4 earthquake in the first several seconds. The current JMA system uses the peak displacement amplitude for the magnitude estimation, and the magnitude saturated at about M8 1 minute after the first P-wave arrival. . Magnitudes of smaller earthquakes can be correctly identified from the first few seconds of P- or S-wave arrivals, but this M9 event cannot be characterized in such a short time. The only way to correctly characterize the size of the Tohoku
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Hiemer, Stefan; Roessler, Dirk; Scherbaum, Frank
2012-04-01
The most recent intense earthquake swarm in West Bohemia lasted from 6 October 2008 to January 2009. Starting 12 days after the onset, the University of Potsdam monitored the swarm by a temporary small-aperture seismic array at 10 km epicentral distance. The purpose of the installation was a complete monitoring of the swarm including micro-earthquakes ( M L 0.0). In the course of this work, the main temporal features (frequency-magnitude distribution, propagation of back azimuth and horizontal slowness, occurrence rate of aftershock sequences and interevent-time distribution) of the recent 2008/2009 earthquake swarm are presented and discussed. Temporal changes of the coefficient of variation (based on interevent times) suggest that the swarm earthquake activity of the 2008/2009 swarm terminates by 12 January 2009. During the main phase in our studied swarm period after 19 October, the b value of the Gutenberg-Richter relation decreases from 1.2 to 0.8. This trend is also reflected in the power-law behavior of the seismic moment release. The corresponding total seismic moment release of 1.02×1017 Nm is equivalent to M L,max = 5.4.
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Analysis of earthquake clustering and source spectra in the Salton Sea Geothermal Field
Cheng, Y.; Chen, X.
2015-12-01
The Salton Sea Geothermal field is located within the tectonic step-over between San Andreas Fault and Imperial Fault. Since the 1980s, geothermal energy exploration has resulted with step-like increase of microearthquake activities, which mirror the expansion of geothermal field. Distinguishing naturally occurred and induced seismicity, and their corresponding characteristics (e.g., energy release) is important for hazard assessment. Between 2008 and 2014, seismic data recorded by a local borehole array were provided public access from CalEnergy through SCEC data center; and the high quality local recording of over 7000 microearthquakes provides unique opportunity to sort out characteristics of induced versus natural activities. We obtain high-resolution earthquake location using improved S-wave picks, waveform cross-correlation and a new 3D velocity model. We then develop method to identify spatial-temporally isolated earthquake clusters. These clusters are classified into aftershock-type, swarm-type, and mixed-type (aftershock-like, with low skew, low magnitude and shorter duration), based on the relative timing of largest earthquakes and moment-release. The mixed-type clusters are mostly located at 3 - 4 km depth near injection well; while aftershock-type clusters and swarm-type clusters also occur further from injection well. By counting number of aftershocks within 1day following mainshock in each cluster, we find that the mixed-type clusters have much higher aftershock productivity compared with other types and historic M4 earthquakes. We analyze detailed spatial variation of 'b-value'. We find that the mixed-type clusters are mostly located within high b-value patches, while large (M>3) earthquakes and other types of clusters are located within low b-value patches. We are currently processing P and S-wave spectra to analyze the spatial-temporal correlation of earthquake stress parameter and seismicity characteristics. Preliminary results suggest that the
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International Nuclear Information System (INIS)
Lee, Gi Hwa
1997-11-01
The purpose of the present study is to develop predictive equations from simulated motions which are adequate for the Korean Peninsula and analyze and utilize the computer programs for the probabilistic estimation of design earthquakes. In part I of the report, computer programs for the probabilistic estimation of design earthquake are analyzed and applied to the seismic hazard characterizations in the Korean Peninsula. In part II of the report, available instrumental earthquake records are analyzed to estimate earthquake source characteristics and medium properties, which are incorporated into simulation process. And earthquake records are simulated by using the estimated parameters. Finally, predictive equations constructed from the simulation are given in terms of magnitude and hypocentral distances
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Fast rise times and the physical mechanism of deep earthquakes
Houston, H.; Williams, Q.
1991-01-01
A systematic global survey of the rise times and stress drops of deep and intermediate earthquakes is reported. When the rise times are scaled to the seismic moment release of the events, their average is nearly twice as fast for events deeper than about 450 km as for shallower events.
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Influence of LOD variations on seismic energy release
Riguzzi, F.; Krumm, F.; Wang, K.; Kiszely, M.; Varga, P.
2009-04-01
Tidal friction causes significant time variations of geodynamical parameters, among them geometrical flattening. The axial despinning of the Earth due to tidal friction through the change of flattening generates incremental meridional and azimuthal stresses. The stress pattern in an incompressible elastic upper mantle and crust is symmetric to the equator and has its inflection points at the critical latitude close to ±45°. Consequently the distribution of seismic energy released by strong, shallow focus earthquakes should have also sharp maxima at this latitude. To investigate the influence of length of day (LOD) variations on earthquake activity an earthquake catalogue of strongest seismic events (M>7.0) was completed for the period 1900-2007. It is shown with the use of this catalogue that for the studied time-interval the catalogue is complete and consists of the seismic events responsible for more than 90% of released seismic energy. Study of the catalogue for earthquakes M>7.0 shows that the seismic energy discharged by the strongest seismic events has significant maxima at ±45°, what renders probably that the seismic activity of our planet is influenced by an external component, i.e. by the tidal friction, which acts through the variation of the hydrostatic figure of the Earth caused by it. Distribution along the latitude of earthquake numbers and energies was investigated also for the case of global linear tectonic structures, such as mid ocean ridges and subduction zones. It can be shown that the number of the shallow focus shocks has a repartition along the latitude similar to the distribution of the linear tectonic structures. This means that the position of foci of seismic events is mainly controlled by the tectonic activity.
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Braunagel, M. J.; Griffith, W. A.
2017-12-01
Past experimental work has demonstrated that rock failure at high strain rates occurs by fragmentation rather than discrete fracture and is accompanied by a dramatic increase in rock strength. However, these observations are difficult to reconcile with the assertion that pulverized rocks in fault zones are the product of impulsive stresses during the passage of earthquake ruptures, as the distance from the principal slip zones of some pulverized rock is too great to exceed fragmentation transition. One potential explanation to this paradox that has been suggested is that repeated loading over the course of multiple earthquake ruptures may gradually reduce the pulverization threshold, in terms of both strain rate and strength. We propose that oscillatory loading during a single earthquake rupture may further lower these pulverization thresholds, and that traditional dynamic experimental approaches, such as the Split Hopkinson Pressure Bar (SHPB) wherein load is applied as a single, smooth, sinusoidal compressive wave, may not reflect natural loading conditions. To investigate the effects of oscillatory compressive loading expected during earthquake rupture propagation, we develop a controlled cyclic loading model on a SHPB apparatus utilizing two striker bars connected by an elastic spring. Unlike traditional SHPB experiments that utilize a gas gun to fire a projectile bar and generate a single compressive wave on impact with the incident bar, our modified striker bar assembly oscillates while moving down the gun barrel and generates two separate compressive pulses separated by a lag time. By modeling the modified assembly as a mass-spring-mass assembly accelerating due to the force of the released gas, we can predict the compression time of the spring upon impact and therefore the time delay between the generation of the first and second compressive waves. This allows us to predictably control load cycles with durations of only a few hundred microseconds. Initial
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International Nuclear Information System (INIS)
Peresan, Antonella; Panza, Giuliano F.; Gorshkov, Alexander I.; Aoudia, Abdelkrim
2001-05-01
Several algorithms, structured according to a general pattern-recognition scheme, have been developed for the space-time identification of strong events. Currently, two of such algorithms are applied to the Italian territory, one for the recognition of earthquake-prone areas and the other, namely CN algorithm, for earthquake prediction purposes. These procedures can be viewed as independent experts, hence they can be combined to better constrain the alerted seismogenic area. We examine here the possibility to integrate CN intermediate-term medium-range earthquake predictions, pattern recognition of earthquake-prone areas and deterministic hazard maps, in order to associate CN Times of Increased Probability (TIPs) to a set of appropriate scenarios of ground motion. The advantage of this procedure mainly consists in the time information provided by predictions, useful to increase preparedness of safety measures and to indicate a priority for detailed seismic risk studies to be performed at a local scale. (author)
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Identification of radon anomalies related to earthquakes
International Nuclear Information System (INIS)
Ozdas, M.; Inceoglu, F.; Rahman, C.; Yaprak, G.
2009-01-01
Put of many proposed earthquake precursors, temporal radon variation in soil is classified as one of a few promising geochemical signals that may be used for earthquake prediction. However, to use radon variation in soil gas as a reliable earthquake precursor, it must be realized that radon changes are controlled not only by deeper phenomena such as earthquake, but they are also controlled by meteorological parameters such as precipitation, barometric pressure, air temperature and etc. Further studies are required to differentiate the changes in the measured radon concentration caused by tectonic disturbances from the meteorological parameters. In the current study, temporal radon variations in soil gas along active faults in Alasehir of Gediz Graben Systems have been continuously monitored by LR-115 nuclear track detectors for two years. Additionally, the meteorological parameters such as barometric pressure, rainfall and air temperature at the monitoring site have been observed during the same period. Accordingly, regression analysis have been applied to the collected data to identify the radon anomalies due to the seismic activities from those of meteorological conditions.
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Global risk of big earthquakes has not recently increased.
Shearer, Peter M; Stark, Philip B
2012-01-17
The recent elevated rate of large earthquakes has fueled concern that the underlying global rate of earthquake activity has increased, which would have important implications for assessments of seismic hazard and our understanding of how faults interact. We examine the timing of large (magnitude M≥7) earthquakes from 1900 to the present, after removing local clustering related to aftershocks. The global rate of M≥8 earthquakes has been at a record high roughly since 2004, but rates have been almost as high before, and the rate of smaller earthquakes is close to its historical average. Some features of the global catalog are improbable in retrospect, but so are some features of most random sequences--if the features are selected after looking at the data. For a variety of magnitude cutoffs and three statistical tests, the global catalog, with local clusters removed, is not distinguishable from a homogeneous Poisson process. Moreover, no plausible physical mechanism predicts real changes in the underlying global rate of large events. Together these facts suggest that the global risk of large earthquakes is no higher today than it has been in the past.
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Jiang, Zhongshan; Huang, Dingfa; Yuan, Linguo; Hassan, Abubakr; Zhang, Lupeng; Yang, Zhongrong
2018-04-01
The 2016 moment magnitude (Mw) 7.8 Kaikoura earthquake demonstrated that multiple fault segments can undergo rupture during a single seismic event. Here, we employ Global Positioning System (GPS) observations and geodetic modeling methods to create detailed images of coseismic slip and postseismic afterslip associated with the Kaikoura earthquake. Our optimal geodetic coseismic model suggests that rupture not only occurred on shallow crustal faults but also to some extent at the Hikurangi subduction interface. The GPS-inverted moment release during the earthquake is equivalent to a Mw 7.9 event. The near-field postseismic deformation is mainly derived from right-lateral strike-slip motions on shallow crustal faults. The afterslip did not only significantly extend northeastward on the Needles fault but also appeared at the plate interface, slowly releasing energy over the past 6 months, equivalent to a Mw 7.3 earthquake. Coulomb stress changes induced by coseismic deformation exhibit complex patterns and diversity at different depths, undoubtedly reflecting multi-fault rupture complexity associated with the earthquake. The Coulomb stress can reach several MPa during coseismic deformation, which can explain the trigger mechanisms of afterslip in two high-slip regions and the majority of aftershocks. Based on the deformation characteristics of the Kaikoura earthquake, interseismic plate coverage, and historical earthquakes, we conclude that Wellington is under higher seismic threat after the earthquake and great attention should be paid to potential large earthquake disasters in the near future.[Figure not available: see fulltext.
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International Nuclear Information System (INIS)
2000-08-01
This report includes a final comment made and released by the advisory committee set up for fiscal 2001 by Japan Nuclear Cycle Development Institute (JNC) for inquiry into research progress in subsurface structure and physical properties at Tono Geoscience Center. The appendices contain the membership of the committee, the investigation procedure of the committee, the research subjects and objectives, the experimental results obtained and data included in the interim report including earthquake prediction study and its application for rock mechanics, geochemical and hydrological measurements and monitoring groundwater behaviors, and other materials submitted at the committee for the investigation. (S. Ohno)
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a Collaborative Cyberinfrastructure for Earthquake Seismology
Bossu, R.; Roussel, F.; Mazet-Roux, G.; Lefebvre, S.; Steed, R.
2013-12-01
One of the challenges in real time seismology is the prediction of earthquake's impact. It is particularly true for moderate earthquake (around magnitude 6) located close to urbanised areas, where the slightest uncertainty in event location, depth, magnitude estimates, and/or misevaluation of propagation characteristics, site effects and buildings vulnerability can dramatically change impact scenario. The Euro-Med Seismological Centre (EMSC) has developed a cyberinfrastructure to collect observations from eyewitnesses in order to provide in-situ constraints on actual damages. This cyberinfrastructure takes benefit of the natural convergence of earthquake's eyewitnesses on EMSC website (www.emsc-csem.org), the second global earthquake information website within tens of seconds of the occurrence of a felt event. It includes classical crowdsourcing tools such as online questionnaires available in 39 languages, and tools to collect geolocated pics. It also comprises information derived from the real time analysis of the traffic on EMSC website, a method named flashsourcing; In case of a felt earthquake, eyewitnesses reach EMSC website within tens of seconds to find out the cause of the shaking they have just been through. By analysing their geographical origin through their IP address, we automatically detect felt earthquakes and in some cases map the damaged areas through the loss of Internet visitors. We recently implemented a Quake Catcher Network (QCN) server in collaboration with Stanford University and the USGS, to collect ground motion records performed by volunteers and are also involved in a project to detect earthquakes from ground motions sensors from smartphones. Strategies have been developed for several social media (Facebook, Twitter...) not only to distribute earthquake information, but also to engage with the Citizens and optimise data collection. A smartphone application is currently under development. We will present an overview of this
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Mental Health of Survivors of the 2010 Haitian Earthquake Living in the United States
Centers for Disease Control (CDC) Podcasts
2010-04-16
Thousands of survivors of the 2010 Haitian Earthquake are currently living in the United States. This podcast features a brief non-disease-specific interview with Dr. Marc Safran, CDC's longest serving psychiatrist, about a few of the mental health challenges such survivors may face. Created: 4/16/2010 by CDC Center of Attribution: Mental and Behavioral Health Team, 2010 CDC Haiti Earthquake Mission, CDC Emergency Operations Center. Date Released: 5/6/2010.
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The Value, Protocols, and Scientific Ethics of Earthquake Forecasting
Jordan, Thomas H.
2013-04-01
Earthquakes are different from other common natural hazards because precursory signals diagnostic of the magnitude, location, and time of impending seismic events have not yet been found. Consequently, the short-term, localized prediction of large earthquakes at high probabilities with low error rates (false alarms and failures-to-predict) is not yet feasible. An alternative is short-term probabilistic forecasting based on empirical statistical models of seismic clustering. During periods of high seismic activity, short-term earthquake forecasts can attain prospective probability gains up to 1000 relative to long-term forecasts. The value of such information is by no means clear, however, because even with hundredfold increases, the probabilities of large earthquakes typically remain small, rarely exceeding a few percent over forecasting intervals of days or weeks. Civil protection agencies have been understandably cautious in implementing operational forecasting protocols in this sort of "low-probability environment." This paper will explore the complex interrelations among the valuation of low-probability earthquake forecasting, which must account for social intangibles; the protocols of operational forecasting, which must factor in large uncertainties; and the ethics that guide scientists as participants in the forecasting process, who must honor scientific principles without doing harm. Earthquake forecasts possess no intrinsic societal value; rather, they acquire value through their ability to influence decisions made by users seeking to mitigate seismic risk and improve community resilience to earthquake disasters. According to the recommendations of the International Commission on Earthquake Forecasting (www.annalsofgeophysics.eu/index.php/annals/article/view/5350), operational forecasting systems should appropriately separate the hazard-estimation role of scientists from the decision-making role of civil protection authorities and individuals. They should
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Saylor, David M; Craven, Brent A; Chandrasekar, Vaishnavi; Simon, David D; Brown, Ronald P; Sussman, Eric M
2018-04-01
Many cardiovascular device alloys contain nickel, which if released in sufficient quantities, can lead to adverse health effects. However, in-vivo nickel release from implanted devices and subsequent biodistribution of nickel ions to local tissues and systemic circulation are not well understood. To address this uncertainty, we have developed a multi-scale (material, tissue, and system) biokinetic model. The model links nickel release from an implanted cardiovascular device to concentrations in peri-implant tissue, as well as in serum and urine, which can be readily monitored. The model was parameterized for a specific cardiovascular implant, nitinol septal occluders, using in-vitro nickel release test results, studies of ex-vivo uptake into heart tissue, and in-vivo and clinical measurements from the literature. Our results show that the model accurately predicts nickel concentrations in peri-implant tissue in an animal model and in serum and urine of septal occluder patients. The congruity of the model with these data suggests it may provide useful insight to establish nickel exposure limits and interpret biomonitoring data. Finally, we use the model to predict local and systemic nickel exposure due to passive release from nitinol devices produced using a wide range of manufacturing processes, as well as general relationships between release rate and exposure. These relationships suggest that peri-implant tissue and serum levels of nickel will remain below 5 μg/g and 10 μg/l, respectively, in patients who have received implanted nitinol cardiovascular devices provided the rate of nickel release per device surface area does not exceed 0.074 μg/(cm 2 d) and is less than 32 μg/d in total. The uncertainty in whether in-vitro tests used to evaluate metal ion release from medical products are representative of clinical environments is one of the largest roadblocks to establishing the associated patient risk. We have developed and validated a multi
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Ibrion, Mihaela
2018-01-01
This book chapter brings to attention the dramatic impact of large earthquake disasters on local communities and society and highlights the necessity of building and enhancing the earthquake culture. Iran was considered as a research case study and fifteen large earthquake disasters in Iran were investigated and analyzed over more than a century-time period. It was found that the earthquake culture in Iran was and is still conditioned by many factors or parameters which are not integrated and...
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TSUNAMIGENIC SOURCE MECHANISM AND EFFICIENCY OF THE MARCH 11, 2011 SANRIKU EARTHQUAKE IN JAPAN
Directory of Open Access Journals (Sweden)
George Pararas-Carayannis
2011-01-01
Full Text Available The great Tohoku earthquake of March 11, 2011 generated a very destructive and anomalously high tsunami. To understand its source mechanism, an examination was undertaken of the seismotectonics of the region and of the earthquake’ focal mechanism, energy release, rupture patterns and spatial and temporal sequencing and clustering of major aftershocks. It was determined that the great tsunami resulted from a combination of crustal deformations of the ocean floor due to up-thrust tectonic motions, augmented by additional uplift due to the quake’s slow and long rupturing process, as well as to large coseismic lateral movements which compressed and deformed the compacted sediments along the accretionary prism of the overriding plane. The deformation occurred randomly and non-uniformly along parallel normal faults and along oblique, en-echelon faults to the earthquake’s overall rupture direction – the latter failing in a sequential bookshelf manner with variable slip angles. As the 1992 Nicaragua and the 2004 Sumatra earthquakes demonstrated, such bookshelf failures of sedimentary layers could contribute to anomalously high tsunamis. As with the 1896 tsunami, additional ocean floor deformation and uplift of the sediments was responsible for the higher waves generated by the 2011 earthquake. The efficiency of tsunami generation was greater along the shallow eastern segment of the fault off the Miyagi Prefecture where most of the energy release of the earthquake and the deformations occurred, while the segment off the Ibaraki Prefecture – where the rupture process was rapid – released less seismic energy, resulted in less compaction and deformation of sedimentary layers and thus to a tsunami of lesser offshore height. The greater tsunamigenic efficiency of the 2011 earthquake and high degree of the tsunami’s destructiveness along Honshu’s coastlines resulted from vertical crustal displacements of more than 10 meters due to up
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Non-Stationary Modelling and Simulation of Near-Source Earthquake Ground Motion
DEFF Research Database (Denmark)
Skjærbæk, P. S.; Kirkegaard, Poul Henning; Fouskitakis, G. N.
1997-01-01
This paper is concerned with modelling and simulation of near-source earthquake ground motion. Recent studies have revealed that these motions show heavy non-stationary behaviour with very low frequencies dominating parts of the earthquake sequence. Modeling and simulation of this behaviour...... by an epicentral distance of 16 km and measured during the 1979 Imperial Valley earthquake in California (U .S .A.). The results of the study indicate that while all three approaches can successfully predict near-source ground motions, the Neural Network based one gives somewhat poorer simulation results....
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Non-Stationary Modelling and Simulation of Near-Source Earthquake Ground Motion
DEFF Research Database (Denmark)
Skjærbæk, P. S.; Kirkegaard, Poul Henning; Fouskitakis, G. N.
This paper is concerned with modelling and simulation of near-source earthquake ground motion. Recent studies have revealed that these motions show heavy non-stationary behaviour with very low frequencies dominating parts of the earthquake sequence. Modelling and simulation of this behaviour...... by an epicentral distance of 16 km and measured during the 1979 Imperial valley earthquake in California (USA). The results of the study indicate that while all three approaches can succesfully predict near-source ground motions, the Neural Network based one gives somewhat poorer simulation results....
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Tsai, M. C.; Hu, J. C.; Yang, Y. H.; Hashimoto, M.; Aurelio, M.; Su, Z.; Escudero, J. A.
2017-12-01
Multi-sight and high spatial resolution interferometric SAR data enhances our ability for mapping detailed coseismic deformation to estimate fault rupture model and to infer the Coulomb stress change associated with a big earthquake. Here, we use multi-sight coseismic interferograms acquired by ALOS-2 and Sentinel-1A satellites to estimate the fault geometry and slip distribution on the fault plane of the 2017 Mw 6.5 Ormoc Earthquake in Leyte island of Philippine. The best fitting model predicts that the coseismic rupture occurs along a fault plane with strike of 325.8º and dip of 78.5ºE. This model infers that the rupture of 2017 Ormoc earthquake is dominated by left-lateral slip with minor dip-slip motion, consistent with the left-lateral strike-slip Philippine fault system. The fault tip has propagated to the ground surface, and the predicted coseismic slip on the surface is about 1 m located at 6.5 km Northeast of Kananga city. Significant slip is concentrated on the fault patches at depth of 0-8 km and an along-strike distance of 20 km with varying slip magnitude from 0.3 m to 2.3 m along the southwest segment of this seismogenic fault. Two minor coseismic fault patches are predicted underneath of the Tononan geothermal field and the creeping segment of the northwest portion of this seismogenic fault. This implies that the high geothermal gradient underneath of the Tongonan geothermal filed could prevent heated rock mass from the coseismic failure. The seismic moment release of our preferred fault model is 7.78×1018 Nm, equivalent to Mw 6.6 event. The Coulomb failure stress (CFS) calculated by the preferred fault model predicts significant positive CFS change on the northwest segment of the Philippine fault in Leyte Island which has coseismic slip deficit and is absent from aftershocks. Consequently, this segment should be considered to have increasing of risk for future seismic hazard.
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Tectonic styles of future earthquakes in Italy as input data for seismic hazard
Pondrelli, S.; Meletti, C.; Rovida, A.; Visini, F.; D'Amico, V.; Pace, B.
2017-12-01
In a recent elaboration of a new seismogenic zonation and hazard model for Italy, we tried to understand how many indications we have on the tectonic style of future earthquake/rupture. Using all available or recomputed seismic moment tensors for relevant seismic events (Mw starting from 4.5) of the last 100 yrs, first arrival focal mechanisms for less recent earthquakes and also geological data on past activated faults, we collected a database gathering a thousands of data all over the Italian peninsula and regions around it. After several summations of seismic moment tensors, over regular grids of different dimensions and different thicknesses of the seismogenic layer, we applied the same procedure to each of the 50 area sources that were designed in the seismogenic zonation. The results for several seismic zones are very stable, e.g. along the southern Apennines we expect future earthquakes to be mostly extensional, although in the outer part of the chain strike-slip events are possible. In the Northern part of the Apennines we also expect different, opposite tectonic styles for different hypocentral depths. In several zones, characterized by a low seismic moment release, defined for the study region using 1000 yrs of catalog, the next possible tectonic style of future earthquakes is less clear. It is worth to note that for some zones the possible greatest earthquake could be not represented in the available observations. We also add to our analysis the computation of the seismic release rate, computed using a distributed completeness, identified for single great events of the historical seismic catalog for Italy. All these information layers, overlapped and compared, may be used to characterize each new seismogenic zone.
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The earthquakes of stable continental regions. Volume 2: Appendices A to E. Final report
International Nuclear Information System (INIS)
Johnston, A.C.; Kanter, L.R.; Coppersmith, K.J.; Cornell, C.A.
1994-12-01
The objectives of the study were to develop a comprehensive database of earthquakes in stable continental regions (SCRs) and to statistically examine use of the database for the assessment of large earthquake potential. We identified nine major and several minor SCRs worldwide and compiled a database of geologic characteristics of tectonic domains within each SCR. We examined all available earthquake data from SCRs, from historical accounts of events with no instrumental ground-motion data to present-day instrumentally recorded events. In all, 1,385 events were analyzed. Using moment magnitude 4.5 as the lower bound threshold for inclusion in the database, 870 were assigned to an SCR, 124 were found to be transitional to an SCR, and 391 were examined, but rejected. We then performed a seismotectonic analysis to determine what distinguishes seismic activity in SCRs from other types of crust, such as active plate margins or active continental regions. General observations are: (1) SCRs comprise nearly two-thirds of all continental crust of which 25% is considered to be extended (i.e., rifted); (2) the majority of seismic energy release and the largest earthquakes in SCRs have occurred in extended crust; and (3) active plate margins release seismic energy at a rate per unit area approximately 7,000 times the average for non-extended SCRs. Finally, results of a statistical examination of distributions of historical maximum earthquakes between different crustal domain types indicated that additional information is needed in order to adequately constrain estimates of maximum earthquakes for any given region. Thus, a Bayesian approach was developed in which statistical constraints from the database were used to develop a prior distribution, which may then be combined with source-specific information to constrain maximum magnitude assessments for use in probabilistic seismic hazard analyses
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A review on remotely sensed land surface temperature anomaly as an earthquake precursor
Bhardwaj, Anshuman; Singh, Shaktiman; Sam, Lydia; Joshi, P. K.; Bhardwaj, Akanksha; Martín-Torres, F. Javier; Kumar, Rajesh
2017-12-01
The low predictability of earthquakes and the high uncertainty associated with their forecasts make earthquakes one of the worst natural calamities, capable of causing instant loss of life and property. Here, we discuss the studies reporting the observed anomalies in the satellite-derived Land Surface Temperature (LST) before an earthquake. We compile the conclusions of these studies and evaluate the use of remotely sensed LST anomalies as precursors of earthquakes. The arrival times and the amplitudes of the anomalies vary widely, thus making it difficult to consider them as universal markers to issue earthquake warnings. Based on the randomness in the observations of these precursors, we support employing a global-scale monitoring system to detect statistically robust anomalous geophysical signals prior to earthquakes before considering them as definite precursors.
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Radon anomaly in soil gas as an earthquake precursor
International Nuclear Information System (INIS)
Miklavcic, I.; Radolic, V.; Vukovic, B.; Poje, M.; Varga, M.; Stanic, D.; Planinic, J.
2008-01-01
The mechanical processes of earthquake preparation are always accompanied by deformations; afterwards, the complex short- or long-term precursory phenomena can appear. Anomalies of radon concentrations in soil gas are registered a few weeks or months before many earthquakes. Radon concentrations in soil gas were continuously measured by the LR-115 nuclear track detectors at site A (Osijek) during a 4-year period, as well as by the Barasol semiconductor detector at site B (Kasina) during 2 years. We investigated the influence of the meteorological parameters on the temporal radon variations, and we determined the equation of the multiple regression that enabled the reduction (deconvolution) of the radon variation caused by the barometric pressure, rainfall and temperature. The pre-earthquake radon anomalies at site A indicated 46% of the seismic events, on criterion M≥3, R<200 km, and 21% at site B. Empirical equations between earthquake magnitude, epicenter distance and precursor time enabled estimation or prediction of an earthquake that will rise at the epicenter distance R from the monitoring site in expecting precursor time T
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Radon anomaly in soil gas as an earthquake precursor
Energy Technology Data Exchange (ETDEWEB)
Miklavcic, I.; Radolic, V.; Vukovic, B.; Poje, M.; Varga, M.; Stanic, D. [Department of Physics, University of Osijek, Trg Ljudevita Gaja 6, POB 125, 31000 Osijek (Croatia); Planinic, J. [Department of Physics, University of Osijek, Trg Ljudevita Gaja 6, POB 125, 31000 Osijek (Croatia)], E-mail: planinic@ffos.hr
2008-10-15
The mechanical processes of earthquake preparation are always accompanied by deformations; afterwards, the complex short- or long-term precursory phenomena can appear. Anomalies of radon concentrations in soil gas are registered a few weeks or months before many earthquakes. Radon concentrations in soil gas were continuously measured by the LR-115 nuclear track detectors at site A (Osijek) during a 4-year period, as well as by the Barasol semiconductor detector at site B (Kasina) during 2 years. We investigated the influence of the meteorological parameters on the temporal radon variations, and we determined the equation of the multiple regression that enabled the reduction (deconvolution) of the radon variation caused by the barometric pressure, rainfall and temperature. The pre-earthquake radon anomalies at site A indicated 46% of the seismic events, on criterion M{>=}3, R<200 km, and 21% at site B. Empirical equations between earthquake magnitude, epicenter distance and precursor time enabled estimation or prediction of an earthquake that will rise at the epicenter distance R from the monitoring site in expecting precursor time T.
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International Nuclear Information System (INIS)
Bonner, N.A.; Ng, Y.C.
1980-03-01
The BIODOSE computer program simulates the environmental transport of radionuclides released to surface water and predicts the resulting dosage to humans. This report describes the program and discusses its use in the evaluation of nuclear waste repositories. The methods used to estimate dose are examined critically, and the most important parameters in each stage of the calculations are identified as an aid in planning for measurements in the field. Dose predictions from releases of nuclear waste to a large northwestern river (the baseline river) are presented to point out the nuclides, compartments and pathways that contribute most to the hazard as a function of waste storage time. Predictions for five other water systems are presented to identify the most important system parameters that determine the concentrations of individual nuclides in compartments and the resultant dose. The uncertainties in the biological parameters for dose prediction are identified, and changes in current values are suggested. Various ways of reporting dose estimates for radiological safety assessments are discussed. Additional work needed to improve the dose predictions from BIODOSE and specific areas and steps to improve our capabilities to assess the environmental transport of nuclides released from nuclear waste repositories and the resultant dose to man are suggested
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Rupture distribution of the 1977 western Argentina earthquake
Langer, C.J.; Hartzell, S.
1996-01-01
Teleseismic P and SH body waves are used in a finite-fault, waveform inversion for the rupture history of the 23 November 1977 western Argentina earthquake. This double event consists of a smaller foreshock (M0 = 5.3 ?? 1026 dyn-cm) followed about 20 s later by a larger main shock (M0 = 1.5 ?? 1027 dyn-cm). Our analysis indicates that these two events occurred on different fault segments: with the foreshock having a strike, dip, and average rake of 345??, 45??E, and 50??, and the main shock 10??, 45??E, and 80??, respectively. The foreshock initiated at a depth of 17 km and propagated updip and to the north. The main shock initiated at the southern end of the foreshock zone at a depth of 25 to 30 km, and propagated updip and unilaterally to the south. The north-south separation of the centroids of the moment release for the foreshock and main shock is about 60 km. The apparent triggering of the main shock by the foreshock is similar to other earthquakes that have involved the failure of multiple fault segments, such as the 1992 Landers, California, earthquake. Such occurrences argue against the use of individual, mapped, surface fault or fault-segment lengths in the determination of the size and frequency of future earthquakes.
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International Nuclear Information System (INIS)
Peurrung, L.M.; Caley, S.M.; Gauglitz, P.A.
1997-08-01
The Hanford Site has 149 single-shell tanks (SSTs) containing radioactive wastes that are complex mixes of radioactive and chemical products. Of these, 67 are known or suspected to have leaked liquid from the tanks into the surrounding soil. Salt-well pumping, or interim stabilization, is a well-established operation for removing drainable interstitial liquid from SSTs. The overall objective of this ongoing study is to develop a quantitative understanding of the release rates and cumulative releases of flammable gases from SSTs as a result of salt-well pumping. The current study is an extension of the previous work reported by Peurrung et al. (1996). The first objective of this current study was to conduct laboratory experiments to quantify the release of soluble and insoluble gases. The second was to determine experimentally the role of characteristic waste heterogeneities on the gas release rates. The third objective was to evaluate and validate the computer model STOMP (Subsurface Transport over Multiple Phases) used by Peurrung et al. (1996) to predict the release of both soluble (typically ammonia) and insoluble gases (typically hydrogen) during and after salt-well pumping. The fourth and final objective of the current study was to predict the gas release behavior for a range of typical tank conditions and actual tank geometry. In these models, the authors seek to include all the pertinent salt-well pumping operational parameters and a realistic range of physical properties of the SST wastes. For predicting actual tank behavior, two-dimensional (2-D) simulations were performed with a representative 2-D tank geometry
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International Nuclear Information System (INIS)
Hofmann, R.B.
1995-01-01
Analogs are used to understand complex or poorly understood phenomena for which little data may be available at the actual repository site. Earthquakes are complex phenomena, and they can have a large number of effects on the natural system, as well as on engineered structures. Instrumental data close to the source of large earthquakes are rarely obtained. The rare events for which measurements are available may be used, with modfications, as analogs for potential large earthquakes at sites where no earthquake data are available. In the following, several examples of nuclear reactor and liquified natural gas facility siting are discussed. A potential use of analog earthquakes is proposed for a high-level nuclear waste (HLW) repository
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Honda, Ryou; Yukutake, Yohei; Ito, Hiroshi; Harada, Masatake; Aketagawa, Tamotsu; Yoshida, Akio; Sakai, Shin'ichi; Nakagawa, Shigeki; Hirata, Naoshi; Obara, Kazushige; Kimura, Hisanori
2011-07-01
Strong ground motions from the 2011 off the Pacific coast of Tohoku Earthquake, the most powerful earthquake to have occurred in and around Japan after the installation of a modern seismic network, were recorded for more than 300 seconds by a dense and wide-span seismic network, the Metropolitan Seismic Observation Network (MeSO-net), installed around the Tokyo metropolitan area about 200 km away from the epicenter. We investigate the rupture process of the earthquake in space and time by performing semblance-enhanced stacking analysis of the waveforms in a frequency range of 0.05 to 0.5 Hz. By projecting the power of the stacked waveforms to an assumed fault plane, the rupture propagation image of the large and complex earthquake has been successfully obtained. The seismic energy was mainly generated from the off-shore areas of about 100 km away from the coast in Miyagi and Fukushima Prefectures. The shallow and eastern part of the fault along the Japan trench off Miyagi Prefecture released strong seismic energy which might have been related to the excitation of gigantic tsunami. In contrast, the southern shallow part of the fault plane, off Ibaraki Prefecture, released only minor seismic energy. Our analysis suggests that the focal areas combining both the officially-forecasted Miyagi-oki earthquake and those of historical earthquakes that occurred off the coast of Fukushima Prefecture in 1938 were broken, resulting in the 2011 great M 9 earthquake.
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An update on radioactive release and exposures after the Fukushima Dai-ichi nuclear disaster.
LENUS (Irish Health Repository)
McLaughlin, P D
2012-09-01
On 11 March 2011, the Richter scale 0.9-magnitude Tokohu earthquake and tsunami struck the northeast coast of Japan, resulting in widespread injury and loss of life. Compounding this tragic loss of life, a series of equipment and structural failures at the Fukushima Dai-ichi nuclear power plant (FDNP) resulted in the release of many volatile radioisotopes into the atmosphere. In this update, we detail currently available evidence about the nature of immediate radioactive exposure to FDNP workers and the general population. We contrast the nature of the radioactive exposure at FDNP with that which occurred at the Chernobyl power plant 25 years previously. Prediction of the exact health effects related to the FDNP release is difficult at present and this disaster provides the scientific community with a challenge to help those involved and to continue research that will improve our understanding of the potential complications of radionuclide fallout.
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Characterizing Aftershock Sequences of the Recent Strong Earthquakes in Central Italy
Kossobokov, Vladimir G.; Nekrasova, Anastasia K.
2017-10-01
The recent strong earthquakes in Central Italy allow for a comparative analysis of their aftershocks from the viewpoint of the Unified Scaling Law for Earthquakes, USLE, which generalizes the Gutenberg-Richter relationship making use of naturally fractal distribution of earthquake sources of different size in a seismic region. In particular, we consider aftershocks as a sequence of avalanches in self-organized system of blocks-and-faults of the Earth lithosphere, each aftershock series characterized with the distribution of the USLE control parameter, η. We found the existence, in a long-term, of different, intermittent levels of rather steady seismic activity characterized with a near constant value of η, which switch, in mid-term, at times of transition associated with catastrophic events. On such a transition, seismic activity may follow different scenarios with inter-event time scaling of different kind, including constant, logarithmic, power law, exponential rise/decay or a mixture of those as observed in the case of the ongoing one associated with the three strong earthquakes in 2016. Evidently, our results do not support the presence of universality of seismic energy release, while providing constraints on modelling seismic sequences for earthquake physicists and supplying decision makers with information for improving local seismic hazard assessments.
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Lange, Dietrich; Ruiz, Javier; Carrasco, Sebastián; Manríquez, Paula
2018-04-01
On 2016 December 25, an Mw 7.6 earthquake broke a portion of the Southern Chilean subduction zone south of Chiloé Island, located in the central part of the Mw 9.5 1960 Valdivia earthquake. This region is characterized by repeated earthquakes in 1960 and historical times with very sparse interseismic activity due to the subduction of a young (˜15 Ma), and therefore hot, oceanic plate. We estimate the coseismic slip distribution based on a kinematic finite-fault source model, and through joint inversion of teleseismic body waves and strong motion data. The coseismic slip model yields a total seismic moment of 3.94 × 1020 N.m that occurred over ˜30 s, with the rupture propagating mainly downdip, reaching a peak slip of ˜4.2 m. Regional moment tensor inversion of stronger aftershocks reveals thrust type faulting at depths of the plate interface. The fore- and aftershock seismicity is mostly related to the subduction interface with sparse seismicity in the overriding crust. The 2016 Chiloé event broke a region with increased locking and most likely broke an asperity of the 1960 earthquake. The updip limit of the main event, aftershocks, foreshocks and interseismic activity are spatially similar, located ˜15 km offshore and parallel to Chiloé Islands west coast. The coseismic slip model of the 2016 Chiloé earthquake suggests a peak slip of 4.2 m that locally exceeds the 3.38 m slip deficit that has accumulated since 1960. Therefore, the 2016 Chiloé earthquake possibly released strain that has built up prior to the 1960 Valdivia earthquake.
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Simplified design and evaluation of liquid storage tanks relative to earthquake loading
Energy Technology Data Exchange (ETDEWEB)
Poole, A.B.
1994-06-01
A summary of earthquake-induced damage in liquid storage tanks is provided. The general analysis steps for dynamic response of fluid-filled tanks subject to horizontal ground excitation are discussed. This work will provide major attention to the understanding of observed tank-failure modes. These modes are quite diverse in nature, but many of the commonly appearing patterns are believed to be shell buckling. A generalized and simple-to-apply shell loading will be developed using Fluegge shell theory. The input to this simplified analysis will be horizontal ground acceleration and tank shell form parameters. A dimensionless parameter will be developed and used in predictions of buckling resulting from earthquake-imposed loads. This prediction method will be applied to various tank designs that have failed during major earthquakes and during shaker table tests. Tanks that have not failed will also be reviewed. A simplified approach will be discussed for early design and evaluation of tank shell parameters and materials to provide a high confidence of low probability of failure during earthquakes.
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Research on Collection of Earthquake Disaster Information from the Crowd
Nian, Z.
2017-12-01
In China, the assessment of the earthquake disasters information is mainly based on the inversion of the seismic source mechanism and the pre-calculated population data model, the real information of the earthquake disaster is usually collected through the government departments, the accuracy and the speed need to be improved. And in a massive earthquake like the one in Mexico, the telecommunications infrastructure on ground were damaged , the quake zone was difficult to observe by satellites and aircraft in the bad weather. Only a bit of information was sent out through maritime satellite of other country. Thus, the timely and effective development of disaster relief was seriously affected. Now Chinese communication satellites have been orbiting, people don't only rely on the ground telecom base station to keep communication with the outside world, to open the web page,to land social networking sites, to release information, to transmit images and videoes. This paper will establish an earthquake information collection system which public can participate. Through popular social platform and other information sources, the public can participate in the collection of earthquake information, and supply quake zone information, including photos, video, etc.,especially those information made by unmanned aerial vehicle (uav) after earthqake, the public can use the computer, potable terminals, or mobile text message to participate in the earthquake information collection. In the system, the information will be divided into earthquake zone basic information, earthquake disaster reduction information, earthquake site information, post-disaster reconstruction information etc. and they will been processed and put into database. The quality of data is analyzed by multi-source information, and is controlled by local public opinion on them to supplement the data collected by government departments timely and implement the calibration of simulation results ,which will better guide
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Limiting the effects of earthquakes on gravitational-wave interferometers
Coughlin, Michael; Earle, Paul; Harms, Jan; Biscans, Sebastien; Buchanan, Christopher; Coughlin, Eric; Donovan, Fred; Fee, Jeremy; Gabbard, Hunter; Guy, Michelle; Mukund, Nikhil; Perry, Matthew
2017-01-01
Ground-based gravitational wave interferometers such as the Laser Interferometer Gravitational-wave Observatory (LIGO) are susceptible to ground shaking from high-magnitude teleseismic events, which can interrupt their operation in science mode and significantly reduce their duty cycle. It can take several hours for a detector to stabilize enough to return to its nominal state for scientific observations. The down time can be reduced if advance warning of impending shaking is received and the impact is suppressed in the isolation system with the goal of maintaining stable operation even at the expense of increased instrumental noise. Here, we describe an early warning system for modern gravitational-wave observatories. The system relies on near real-time earthquake alerts provided by the U.S. Geological Survey (USGS) and the National Oceanic and Atmospheric Administration (NOAA). Preliminary low latency hypocenter and magnitude information is generally available in 5 to 20 min of a significant earthquake depending on its magnitude and location. The alerts are used to estimate arrival times and ground velocities at the gravitational-wave detectors. In general, 90% of the predictions for ground-motion amplitude are within a factor of 5 of measured values. The error in both arrival time and ground-motion prediction introduced by using preliminary, rather than final, hypocenter and magnitude information is minimal. By using a machine learning algorithm, we develop a prediction model that calculates the probability that a given earthquake will prevent a detector from taking data. Our initial results indicate that by using detector control configuration changes, we could prevent interruption of operation from 40 to 100 earthquake events in a 6-month time-period.
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Limiting the effects of earthquakes on gravitational-wave interferometers
International Nuclear Information System (INIS)
Coughlin, Michael; Earle, Paul; Harms, Jan; Biscans, Sebastien; Donovan, Fred; Buchanan, Christopher; Coughlin, Eric; Fee, Jeremy; Guy, Michelle; Gabbard, Hunter; Mukund, Nikhil; Perry, Matthew
2017-01-01
Ground-based gravitational wave interferometers such as the Laser Interferometer Gravitational-wave Observatory (LIGO) are susceptible to ground shaking from high-magnitude teleseismic events, which can interrupt their operation in science mode and significantly reduce their duty cycle. It can take several hours for a detector to stabilize enough to return to its nominal state for scientific observations. The down time can be reduced if advance warning of impending shaking is received and the impact is suppressed in the isolation system with the goal of maintaining stable operation even at the expense of increased instrumental noise. Here, we describe an early warning system for modern gravitational-wave observatories. The system relies on near real-time earthquake alerts provided by the U.S. Geological Survey (USGS) and the National Oceanic and Atmospheric Administration (NOAA). Preliminary low latency hypocenter and magnitude information is generally available in 5 to 20 min of a significant earthquake depending on its magnitude and location. The alerts are used to estimate arrival times and ground velocities at the gravitational-wave detectors. In general, 90% of the predictions for ground-motion amplitude are within a factor of 5 of measured values. The error in both arrival time and ground-motion prediction introduced by using preliminary, rather than final, hypocenter and magnitude information is minimal. By using a machine learning algorithm, we develop a prediction model that calculates the probability that a given earthquake will prevent a detector from taking data. Our initial results indicate that by using detector control configuration changes, we could prevent interruption of operation from 40 to 100 earthquake events in a 6-month time-period. (paper)
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Lischka, Juliane A; Stressig, J; Bünzli, F
2016-01-01
News value theory aims to predict a story’s chance of being selected for publication based on news factors and ascribed news values. News values can also predict the coverage of corporate press releases. For news decisions, a newspaper’s revenue model may force editors to consider whether the source of a press release is an advertising client, despite the ‘separation of church and state’. In addition, for business journalism, corporate press releases have become an increasingly important news...
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Ionospheric anomalies detected by ionosonde and possibly related to crustal earthquakes in Greece
Perrone, Loredana; De Santis, Angelo; Abbattista, Cristoforo; Alfonsi, Lucilla; Amoruso, Leonardo; Carbone, Marianna; Cesaroni, Claudio; Cianchini, Gianfranco; De Franceschi, Giorgiana; De Santis, Anna; Di Giovambattista, Rita; Marchetti, Dedalo; Pavòn-Carrasco, Francisco J.; Piscini, Alessandro; Spogli, Luca; Santoro, Francesca
2018-03-01
Ionosonde data and crustal earthquakes with magnitude M ≥ 6.0 observed in Greece during the 2003-2015 period were examined to check if the relationships obtained earlier between precursory ionospheric anomalies and earthquakes in Japan and central Italy are also valid for Greek earthquakes. The ionospheric anomalies are identified on the observed variations of the sporadic E-layer parameters (h'Es, foEs) and foF2 at the ionospheric station of Athens. The corresponding empirical relationships between the seismo-ionospheric disturbances and the earthquake magnitude and the epicentral distance are obtained and found to be similar to those previously published for other case studies. The large lead times found for the ionospheric anomalies occurrence may confirm a rather long earthquake preparation period. The possibility of using the relationships obtained for earthquake prediction is finally discussed.
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Ionospheric anomalies detected by ionosonde and possibly related to crustal earthquakes in Greece
Directory of Open Access Journals (Sweden)
L. Perrone
2018-03-01
Full Text Available Ionosonde data and crustal earthquakes with magnitude M ≥ 6.0 observed in Greece during the 2003–2015 period were examined to check if the relationships obtained earlier between precursory ionospheric anomalies and earthquakes in Japan and central Italy are also valid for Greek earthquakes. The ionospheric anomalies are identified on the observed variations of the sporadic E-layer parameters (h′Es, foEs and foF2 at the ionospheric station of Athens. The corresponding empirical relationships between the seismo-ionospheric disturbances and the earthquake magnitude and the epicentral distance are obtained and found to be similar to those previously published for other case studies. The large lead times found for the ionospheric anomalies occurrence may confirm a rather long earthquake preparation period. The possibility of using the relationships obtained for earthquake prediction is finally discussed.
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The Manchester earthquake swarm of October 2002
Baptie, B.; Ottemoeller, L.
2003-04-01
An earthquake sequence started in the Greater Manchester area of the United Kingdom on October 19, 2002. This has continued to the time of writing and has consisted of more than 100 discrete earthquakes. Three temporary seismograph stations were installed to supplement existing permanent stations and to better understand the relationship between the seismicity and local geology. Due to the urban location, these were experienced by a large number of people. The largest event on October 21 had a magnitude ML 3.9. The activity appears to be an earthquake swarm, since there is no clear distinction between a main shock and aftershocks. However, most of the energy during the sequence was actually released in two earthquakes separated by a few seconds in time, on October 21 at 11:42. Other examples of swarm activity in the UK include Comrie (1788-1801, 1839-46), Glenalmond (1970-72), Doune (1997) and Blackford (1997-98, 2000-01) in central Scotland, Constantine (1981, 1986, 1992-4) in Cornwall, and Johnstonbridge (mid1980s) and Dumfries (1991,1999). The clustering of these events in time and space does suggest that there is a causal relationship between the events of the sequence. Joint hypocenter determination was used to simultaneously locate the swarm earthquakes, determine station corrections and improve the relative locations. It seems likely that all events in the sequence originate from a relatively small source volume. This is supported by the similarities in source mechanism and waveform signals between the various events. Focal depths were found to be very shallow and of the order of about 2-3 km. Source mechanisms determined for the largest of the events show strike-slip solutions along either northeast-southwest or northwest-southeast striking fault planes. The surface expression of faults in the epicentral area is generally northwest-southeast, suggesting that this is the more likely fault plane.
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From Data-Sharing to Model-Sharing: SCEC and the Development of Earthquake System Science (Invited)
Jordan, T. H.
2009-12-01
Earthquake system science seeks to construct system-level models of earthquake phenomena and use them to predict emergent seismic behavior—an ambitious enterprise that requires high degree of interdisciplinary, multi-institutional collaboration. This presentation will explore model-sharing structures that have been successful in promoting earthquake system science within the Southern California Earthquake Center (SCEC). These include disciplinary working groups to aggregate data into community models; numerical-simulation working groups to investigate system-specific phenomena (process modeling) and further improve the data models (inverse modeling); and interdisciplinary working groups to synthesize predictive system-level models. SCEC has developed a cyberinfrastructure, called the Community Modeling Environment, that can distribute the community models; manage large suites of numerical simulations; vertically integrate the hardware, software, and wetware needed for system-level modeling; and promote the interactions among working groups needed for model validation and refinement. Various socio-scientific structures contribute to successful model-sharing. Two of the most important are “communities of trust” and collaborations between government and academic scientists on mission-oriented objectives. The latter include improvements of earthquake forecasts and seismic hazard models and the use of earthquake scenarios in promoting public awareness and disaster management.
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Prevention of strong earthquakes: Goal or utopia?
Mukhamediev, Sh. A.
2010-11-01
In the present paper, we consider ideas suggesting various kinds of industrial impact on the close-to-failure block of the Earth’s crust in order to break a pending strong earthquake (PSE) into a number of smaller quakes or aseismic slips. Among the published proposals on the prevention of a forthcoming strong earthquake, methods based on water injection and vibro influence merit greater attention as they are based on field observations and the results of laboratory tests. In spite of this, the cited proofs are, for various reasons, insufficient to acknowledge the proposed techniques as highly substantiated; in addition, the physical essence of these methods has still not been fully understood. First, the key concept of the methods, namely, the release of the accumulated stresses (or excessive elastic energy) in the source region of a forthcoming strong earthquake, is open to objection. If we treat an earthquake as a phenomenon of a loss in stability, then, the heterogeneities of the physicomechanical properties and stresses along the existing fault or its future trajectory, rather than the absolute values of stresses, play the most important role. In the present paper, this statement is illustrated by the classical examples of stable and unstable fractures and by the examples of the calculated stress fields, which were realized in the source regions of the tsunamigenic earthquakes of December 26, 2004 near the Sumatra Island and of September 29, 2009 near the Samoa Island. Here, just before the earthquakes, there were no excessive stresses in the source regions. Quite the opposite, the maximum shear stresses τmax were close to their minimum value, compared to τmax in the adjacent territory. In the present paper, we provide quantitative examples that falsify the theory of the prevention of PSE in its current form. It is shown that the measures for the prevention of PSE, even when successful for an already existing fault, can trigger or accelerate a catastrophic
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Generation of earthquake signals
International Nuclear Information System (INIS)
Kjell, G.
1994-01-01
Seismic verification can be performed either as a full scale test on a shaker table or as numerical calculations. In both cases it is necessary to have an earthquake acceleration time history. This report describes generation of such time histories by filtering white noise. Analogue and digital filtering methods are compared. Different methods of predicting the response spectrum of a white noise signal filtered by a band-pass filter are discussed. Prediction of both the average response level and the statistical variation around this level are considered. Examples with both the IEEE 301 standard response spectrum and a ground spectrum suggested for Swedish nuclear power stations are included in the report
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Direct methods of soil-structure interaction analysis for earthquake loadings (V)
Energy Technology Data Exchange (ETDEWEB)
Yoon, J. B.; Choi, J. S.; Lee, J. J.; Park, D. U. [Korea Advanced Institute of Science and Technology, Taejon (Korea, Republic of)
1997-07-15
Methodologies of SSI analysis for earthquake loadings have been reviewed. Based on the finite method incorporating infinite element technique for the unbounded exterior region, a computer program for the nonlinear seismic analysis named as 'KIESSI' has been developed. The computer program has been verified using a free-field site-response problem. Post-correlation analysis for the Hualien FVT after backfill and the blind prediction of earthquake responses have been carried out utilizing the developed computer program. The earthquake response analyses for three LSST structures (Hualien, Lotung and Tepsco structure) have also been performed and compared with the measured data.
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Direct methods of soil-structure interaction analysis for earthquake loadings (IV)
Energy Technology Data Exchange (ETDEWEB)
Yoon, J B; Kim, D S; Choi, J S; Kwon, K C; Kim, Y J; Lee, H J; Kim, S B; Kim, D K [Korea Advanced Institute of Science and Technology, Taejon (Korea, Republic of)
1996-07-15
Methodologies of SSI analysis for earthquake loadings have been reviewed. Based on the finite element method incorporating infinite element technique for the unbounded exterior region, a computer program for the nonlinear seismic analysis named as 'KIESSI-QK' has been developed. The computer program has been verified using a free-field site-response problem. The Hualien FVT stochastic finite element analysis after backfill and the blind prediction of earthquake responses have been carried out utilizing the developed computer program. The earthquake response analysis for the LSST structure has also been performed and compared with the measured data.
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Direct methods of soil-structure interaction analysis for earthquake loadings (IV)
Energy Technology Data Exchange (ETDEWEB)
Yoon, J. B.; Kim, D. S.; Choi, J. S.; Kwon, K. C.; Kim, Y. J.; Lee, H. J.; Kim, S. B.; Kim, D. K. [Korea Advanced Institute of Science and Technology, Taejon (Korea, Republic of)
1996-07-15
Methodologies of SSI analysis for earthquake loadings have been reviewed. Based on the finite element method incorporating infinite element technique for the unbounded exterior region, a computer program for the nonlinear seismic analysis named as 'KIESSI-QK' has been developed. The computer program has been verified using a free-field site-response problem. The Hualien FVT stochastic finite element analysis after backfill and the blind prediction of earthquake responses have been carried out utilizing the developed computer program. The earthquake response analysis for the LSST structure has also been performed and compared with the measured data.
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Global observation of Omori-law decay in the rate of triggered earthquakes
Parsons, T.
2001-12-01
Triggered earthquakes can be large, damaging, and lethal as evidenced by the 1999 shocks in Turkey and the 2001 events in El Salvador. In this study, earthquakes with M greater than 7.0 from the Harvard CMT catalog are modeled as dislocations to calculate shear stress changes on subsequent earthquake rupture planes near enough to be affected. About 61% of earthquakes that occurred near the main shocks are associated with calculated shear stress increases, while ~39% are associated with shear stress decreases. If earthquakes associated with calculated shear stress increases are interpreted as triggered, then such events make up at least 8% of the CMT catalog. Globally, triggered earthquakes obey an Omori-law rate decay that lasts between ~7-11 years after the main shock. Earthquakes associated with calculated shear stress increases occur at higher rates than background up to 240 km away from the main-shock centroid. Earthquakes triggered by smaller quakes (foreshocks) also obey Omori's law, which is one of the few time-predictable patterns evident in the global occurrence of earthquakes. These observations indicate that earthquake probability calculations which include interactions from previous shocks should incorporate a transient Omori-law decay with time. In addition, a very simple model using the observed global rate change with time and spatial distribution of triggered earthquakes can be applied to immediately assess the likelihood of triggered earthquakes following large events, and can be in place until more sophisticated analyses are conducted.
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REGIONAL SEISMIC AMPLITUDE MODELING AND TOMOGRAPHY FOR EARTHQUAKE-EXPLOSION DISCRIMINATION
Energy Technology Data Exchange (ETDEWEB)
Walter, W R; Pasyanos, M E; Matzel, E; Gok, R; Sweeney, J; Ford, S R; Rodgers, A J
2008-07-08
We continue exploring methodologies to improve earthquake-explosion discrimination using regional amplitude ratios such as P/S in a variety of frequency bands. Empirically we demonstrate that such ratios separate explosions from earthquakes using closely located pairs of earthquakes and explosions recorded on common, publicly available stations at test sites around the world (e.g. Nevada, Novaya Zemlya, Semipalatinsk, Lop Nor, India, Pakistan, and North Korea). We are also examining if there is any relationship between the observed P/S and the point source variability revealed by longer period full waveform modeling (e. g. Ford et al 2008). For example, regional waveform modeling shows strong tectonic release from the May 1998 India test, in contrast with very little tectonic release in the October 2006 North Korea test, but the P/S discrimination behavior appears similar in both events using the limited regional data available. While regional amplitude ratios such as P/S can separate events in close proximity, it is also empirically well known that path effects can greatly distort observed amplitudes and make earthquakes appear very explosion-like. Previously we have shown that the MDAC (Magnitude Distance Amplitude Correction, Walter and Taylor, 2001) technique can account for simple 1-D attenuation and geometrical spreading corrections, as well as magnitude and site effects. However in some regions 1-D path corrections are a poor approximation and we need to develop 2-D path corrections. Here we demonstrate a new 2-D attenuation tomography technique using the MDAC earthquake source model applied to a set of events and stations in both the Middle East and the Yellow Sea Korean Peninsula regions. We believe this new 2-D MDAC tomography has the potential to greatly improve earthquake-explosion discrimination, particularly in tectonically complex regions such as the Middle East. Monitoring the world for potential nuclear explosions requires characterizing seismic
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On the reported ionospheric precursor of the 1999 Hector Mine, California earthquake
Thomas, Jeremy N.; Love, Jeffrey J.; Komjathy, Attila; Verkhoglyadova, Olga P.; Butala, Mark; Rivera, Nicholas
2012-01-01
Using Global Positioning System (GPS) data from sites near the 16 Oct. 1999 Hector Mine, California earthquake, Pulinets et al. (2007) identified anomalous changes in the ionospheric total electron content (TEC) starting one week prior to the earthquake. Pulinets (2007) suggested that precursory phenomena of this type could be useful for predicting earthquakes. On the other hand, and in a separate analysis, Afraimovich et al. (2004) concluded that TEC variations near the epicenter were controlled by solar and geomagnetic activity that were unrelated to the earthquake. In an investigation of these very different results, we examine TEC time series of long duration from GPS stations near and far from the epicenter of the Hector Mine earthquake, and long before and long after the earthquake. While we can reproduce the essential time series results of Pulinets et al., we find that the signal they identify as anomalous is not actually anomalous. Instead, it is just part of normal global-scale TEC variation. We conclude that the TEC anomaly reported by Pulinets et al. is unrelated to the Hector Mine earthquake.
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Geirsson, Halldor; LaFemina, Peter C.; DeMets, Charles; Hernandez, Douglas Antonio; Mattioli, Glen S.; Rogers, Robert; Rodriguez, Manuel; Marroquin, Griselda; Tenorio, Virginia
2015-09-01
Subduction zones exhibit variable degrees of interseismic coupling as resolved by inversions of geodetic data and analyses of seismic energy release. The degree to which a plate boundary fault is coupled can have profound effects on its seismogenic behaviour. Here we use GPS measurements to estimate co- and post-seismic deformation from the 2012 August 27, Mw7.3 megathrust earthquake offshore El Salvador, which was a tsunami earthquake. Inversions of estimated coseismic displacements are in agreement with published seismically derived source models, which indicate shallow (earthquake exceeds the coseismic deformation. Our analysis indicates that the post-seismic deformation is dominated by afterslip, as opposed to viscous relaxation, and we estimate a post-seismic moment release one to eight times greater than the coseismic moment during the first 500 d, depending on the relative location of coseismic versus post-seismic slip on the plate interface. We suggest that the excessive post-seismic motion is characteristic for the El Salvador-Nicaragua segment of the Central American margin and may be a characteristic of margins hosting tsunami earthquakes.
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Turkish Compulsory Earthquake Insurance and "Istanbul Earthquake
Durukal, E.; Sesetyan, K.; Erdik, M.
2009-04-01
The city of Istanbul will likely experience substantial direct and indirect losses as a result of a future large (M=7+) earthquake with an annual probability of occurrence of about 2%. This paper dwells on the expected building losses in terms of probable maximum and average annualized losses and discusses the results from the perspective of the compulsory earthquake insurance scheme operational in the country. The TCIP system is essentially designed to operate in Turkey with sufficient penetration to enable the accumulation of funds in the pool. Today, with only 20% national penetration, and about approximately one-half of all policies in highly earthquake prone areas (one-third in Istanbul) the system exhibits signs of adverse selection, inadequate premium structure and insufficient funding. Our findings indicate that the national compulsory earthquake insurance pool in Turkey will face difficulties in covering incurring building losses in Istanbul in the occurrence of a large earthquake. The annualized earthquake losses in Istanbul are between 140-300 million. Even if we assume that the deductible is raised to 15%, the earthquake losses that need to be paid after a large earthquake in Istanbul will be at about 2.5 Billion, somewhat above the current capacity of the TCIP. Thus, a modification to the system for the insured in Istanbul (or Marmara region) is necessary. This may mean an increase in the premia and deductible rates, purchase of larger re-insurance covers and development of a claim processing system. Also, to avoid adverse selection, the penetration rates elsewhere in Turkey need to be increased substantially. A better model would be introduction of parametric insurance for Istanbul. By such a model the losses will not be indemnified, however will be directly calculated on the basis of indexed ground motion levels and damages. The immediate improvement of a parametric insurance model over the existing one will be the elimination of the claim processing
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Fault failure with moderate earthquakes
Johnston, M. J. S.; Linde, A. T.; Gladwin, M. T.; Borcherdt, R. D.
1987-12-01
High resolution strain and tilt recordings were made in the near-field of, and prior to, the May 1983 Coalinga earthquake ( ML = 6.7, Δ = 51 km), the August 4, 1985, Kettleman Hills earthquake ( ML = 5.5, Δ = 34 km), the April 1984 Morgan Hill earthquake ( ML = 6.1, Δ = 55 km), the November 1984 Round Valley earthquake ( ML = 5.8, Δ = 54 km), the January 14, 1978, Izu, Japan earthquake ( ML = 7.0, Δ = 28 km), and several other smaller magnitude earthquakes. These recordings were made with near-surface instruments (resolution 10 -8), with borehole dilatometers (resolution 10 -10) and a 3-component borehole strainmeter (resolution 10 -9). While observed coseismic offsets are generally in good agreement with expectations from elastic dislocation theory, and while post-seismic deformation continued, in some cases, with a moment comparable to that of the main shock, preseismic strain or tilt perturbations from hours to seconds (or less) before the main shock are not apparent above the present resolution. Precursory slip for these events, if any occurred, must have had a moment less than a few percent of that of the main event. To the extent that these records reflect general fault behavior, the strong constraint on the size and amount of slip triggering major rupture makes prediction of the onset times and final magnitudes of the rupture zones a difficult task unless the instruments are fortuitously installed near the rupture initiation point. These data are best explained by an inhomogeneous failure model for which various areas of the fault plane have either different stress-slip constitutive laws or spatially varying constitutive parameters. Other work on seismic waveform analysis and synthetic waveforms indicates that the rupturing process is inhomogeneous and controlled by points of higher strength. These models indicate that rupture initiation occurs at smaller regions of higher strength which, when broken, allow runaway catastrophic failure.
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Earthquake potential revealed by tidal influence on earthquake size-frequency statistics
Ide, Satoshi; Yabe, Suguru; Tanaka, Yoshiyuki
2016-11-01
The possibility that tidal stress can trigger earthquakes is long debated. In particular, a clear causal relationship between small earthquakes and the phase of tidal stress is elusive. However, tectonic tremors deep within subduction zones are highly sensitive to tidal stress levels, with tremor rate increasing at an exponential rate with rising tidal stress. Thus, slow deformation and the possibility of earthquakes at subduction plate boundaries may be enhanced during periods of large tidal stress. Here we calculate the tidal stress history, and specifically the amplitude of tidal stress, on a fault plane in the two weeks before large earthquakes globally, based on data from the global, Japanese, and Californian earthquake catalogues. We find that very large earthquakes, including the 2004 Sumatran, 2010 Maule earthquake in Chile and the 2011 Tohoku-Oki earthquake in Japan, tend to occur near the time of maximum tidal stress amplitude. This tendency is not obvious for small earthquakes. However, we also find that the fraction of large earthquakes increases (the b-value of the Gutenberg-Richter relation decreases) as the amplitude of tidal shear stress increases. The relationship is also reasonable, considering the well-known relationship between stress and the b-value. This suggests that the probability of a tiny rock failure expanding to a gigantic rupture increases with increasing tidal stress levels. We conclude that large earthquakes are more probable during periods of high tidal stress.
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The HayWired Earthquake Scenario
Detweiler, Shane T.; Wein, Anne M.
2017-04-24
interconnectedness of infrastructure, society, and our economy. How would this earthquake scenario, striking close to Silicon Valley, impact our interconnected world in ways and at a scale we have not experienced in any previous domestic earthquake?The area of present-day Contra Costa, Alameda, and Santa Clara Counties contended with a magnitude-6.8 earthquake in 1868 on the Hayward Fault. Although sparsely populated then, about 30 people were killed and extensive property damage resulted. The question of what an earthquake like that would do today has been examined before and is now revisited in the HayWired scenario. Scientists have documented a series of prehistoric earthquakes on the Hayward Fault and are confident that the threat of a future earthquake, like that modeled in the HayWired scenario, is real and could happen at any time. The team assembled to build this scenario has brought innovative new approaches to examining the natural hazards, impacts, and consequences of such an event. Such an earthquake would also be accompanied by widespread liquefaction and landslides, which are treated in greater detail than ever before. The team also considers how the now-prototype ShakeAlert earthquake early warning system could provide useful public alerts and automatic actions.Scientific Investigations Report 2017–5013 and accompanying data releases are the products of an effort led by the USGS, but this body of work was created through the combined efforts of a large team including partners who have come together to form the HayWired Coalition (see chapter A). Use of the HayWired scenario has already begun. More than a full year of intensive partner engagement, beginning in April 2017, is being directed toward producing the most in-depth look ever at the impacts and consequences of a large earthquake on the Hayward Fault. With the HayWired scenario, our hope is to encourage and support the active ongoing engagement of the entire community of the San Francisco Bay region by
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Earthquake Safety Tips in the Classroom
Melo, M. O.; Maciel, B. A. P. C.; Neto, R. P.; Hartmann, R. P.; Marques, G.; Gonçalves, M.; Rocha, F. L.; Silveira, G. M.
2014-12-01
The catastrophes induced by earthquakes are among the most devastating ones, causing an elevated number of human losses and economic damages. But, we have to keep in mind that earthquakes don't kill people, buildings do. Earthquakes can't be predicted and the only way of dealing with their effects is to teach the society how to be prepared for them, and how to deal with their consequences. In spite of being exposed to moderate and large earthquakes, most of the Portuguese are little aware of seismic risk, mainly due to the long recurrence intervals between strong events. The acquisition of safe and correct attitudes before, during and after an earthquake is relevant for human security. Children play a determinant role in the establishment of a real and long-lasting "culture of prevention", both through action and new attitudes. On the other hand, when children assume correct behaviors, their relatives often change their incorrect behaviors to mimic the correct behaviors of their kids. In the framework of a Parents-in-Science initiative, we started with bi-monthly sessions for children aged 5 - 6 years old and 9 - 10 years old. These sessions, in which parents, teachers and high-school students participate, became part of the school's permanent activities. We start by a short introduction to the Earth and to earthquakes by story telling and by using simple science activities to trigger children curiosity. With safety purposes, we focus on how crucial it is to know basic information about themselves and to define, with their families, an emergency communications plan, in case family members are separated. Using a shaking table we teach them how to protect themselves during an earthquake. We then finish with the preparation on an individual emergency kit. This presentation will highlight the importance of encouraging preventive actions in order to reduce the impact of earthquakes on society. This project is developed by science high-school students and teachers, in
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Earthquake forewarning — A multidisciplinary challenge from the ground up to space
Freund, Friedemann
2013-08-01
Most destructive earthquakes nucleate at between 5-7 km and about 35-40 km depth. Before earthquakes, rocks are subjected to increasing stress. Not every stress increase leads to rupture. To understand pre-earthquake phenomena we note that igneous and high-grade metamorphic rocks contain defects which, upon stressing, release defect electrons in the oxygen anion sublattice, known as positive holes. These charge carriers are highly mobile, able to flow out of stressed rocks into surrounding unstressed rocks. They form electric currents, which emit electromagnetic radiation, sometimes in pulses, sometimes sustained. The arrival of positive holes at the ground-air interface can lead to air ionization, often exclusively positive. Ionized air rising upward can lead to cloud condensation. The upward flow of positive ions can lead to instabilities in the mesosphere, to mesospheric lightning, to changes in the Total Electron Content (TEC) at the lower edge of the ionosphere, and electric field turbulences. Advances in deciphering the earthquake process can only be achieved in a broadly multidisciplinary spirit.
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Diagnosis of time of increased probability of volcanic earthquakes at Mt. Vesuvius zone
International Nuclear Information System (INIS)
Rotwain, I.; Kuznetsov, I.; De Natale, G.; Peresan, A.; Panza, G.F.
2003-06-01
The possibility of intermediate-term earthquake prediction at Mt. Vesuvius by means of the algorithm CN is explored. CN was originally designed to identify the Times of Increased Probability (TIPs) for the occurrence of strong tectonic earthquakes, with magnitude M ≥ M 0 , within a region a priori delimited. Here the algorithm CN is applied, for the first time, to the analysis of volcanic seismicity. The earthquakes recorded at Mt. Vesuvius, during the period from February 1972 to October 2002, are considered and the magnitude threshold M 0 , selecting the events to be predicted, is varied within the range: 3.0 - 3.3. Satisfactory prediction results are obtained, by retrospective analysis, when a time scaling is introduced. In particular, when the length of the time windows is reduced by a factor 2.5 - 3, with respect to the standard version of CN algorithm, more than 90% of the events with M ≥ M 0 occur within the TIP intervals, with TIPs occupying about 30% of the total time considered. The control experiment 'Seismic History' demonstrates the stability of the obtained results and indicates that the algorithm CN can be applied to monitor the preparation of impending earthquakes with M ≥ 3.0 at Mt. Vesuvius. (author)
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Physics-Based Hazard Assessment for Critical Structures Near Large Earthquake Sources
Hutchings, L.; Mert, A.; Fahjan, Y.; Novikova, T.; Golara, A.; Miah, M.; Fergany, E.; Foxall, W.
2017-09-01
We argue that for critical structures near large earthquake sources: (1) the ergodic assumption, recent history, and simplified descriptions of the hazard are not appropriate to rely on for earthquake ground motion prediction and can lead to a mis-estimation of the hazard and risk to structures; (2) a physics-based approach can address these issues; (3) a physics-based source model must be provided to generate realistic phasing effects from finite rupture and model near-source ground motion correctly; (4) wave propagations and site response should be site specific; (5) a much wider search of possible sources of ground motion can be achieved computationally with a physics-based approach; (6) unless one utilizes a physics-based approach, the hazard and risk to structures has unknown uncertainties; (7) uncertainties can be reduced with a physics-based approach, but not with an ergodic approach; (8) computational power and computer codes have advanced to the point that risk to structures can be calculated directly from source and site-specific ground motions. Spanning the variability of potential ground motion in a predictive situation is especially difficult for near-source areas, but that is the distance at which the hazard is the greatest. The basis of a "physical-based" approach is ground-motion syntheses derived from physics and an understanding of the earthquake process. This is an overview paper and results from previous studies are used to make the case for these conclusions. Our premise is that 50 years of strong motion records is insufficient to capture all possible ranges of site and propagation path conditions, rupture processes, and spatial geometric relationships between source and site. Predicting future earthquake scenarios is necessary; models that have little or no physical basis but have been tested and adjusted to fit available observations can only "predict" what happened in the past, which should be considered description as opposed to prediction
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Directory of Open Access Journals (Sweden)
John Douglas
2015-06-01
Full Text Available This article is concerned with attempting to ‘predict’ (hindcast the damage caused by the L’Aquila 2009 earthquake (Mw 6.3 and, more generally, with the question of how close predicted damage can ever be to observations. Damage is hindcast using a well-established empirical-based approach based on vulnerability indices and macroseismic intensities, adjusted for local site effects. Using information that was available before the earthquake and assuming the same event characteristics as the L’Aquila mainshock, the overall damage is reasonably well predicted but there are considerable differences in the damage pattern. To understand the reasons for these differences, information that was only available after the event were include within the calculation. Despite some improvement in the predicted damage, in particularly by the modification of the vulnerability indices and the parameter influencing the width of the damage distribution, these hindcasts do not match all the details of the observations. This is because of local effects: both in terms of the ground shaking, which is only detectable by the installation of a much denser strong-motion network and a detailed microzonation, and in terms of the building vulnerability, which cannot be modeled using a statistical approach but would require detailed analytical modeling for which calibration data are likely to be lacking. Future studies should concentrate on adjusting the generic components of the approach to make them more applicable to their location of interest. To increase the number of observations available to make these adjustments, we encourage the collection of damage states (and not just habitability classes following earthquakes and also the installation of dense strong-motion networks in built-up areas.
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CSIR Research Space (South Africa)
Durrheim, RJ
2012-05-01
Full Text Available Earthquakes, and the tsunamis and landslides they trigger, pose a serious risk to people living close to plate boundaries, and a lesser but still significant risk to inhabitants of stable continental regions where destructive earthquakes are rare... of experiments that seek to identify reliable precursors of damaging seismic events. 1. Introduction Earthquakes, and the tsunamis and landslides they trigger, pose a serious risk to people living close to plate boundaries, and a lesser but still significant...
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Time Domain Feature Extraction Technique for earth's electric field signal prior to the Earthquake
International Nuclear Information System (INIS)
Astuti, W; Sediono, W; Akmeliawati, R; Salami, M J E
2013-01-01
Earthquake is one of the most destructive of natural disasters that killed many people and destroyed a lot of properties. By considering these catastrophic effects, it is highly important of knowing ahead of earthquakes in order to reduce the number of victims and material losses. Earth's electric field is one of the features that can be used to predict earthquakes (EQs), since it has significant changes in the amplitude of the signal prior to the earthquake. This paper presents a detailed analysis of the earth's electric field due to earthquakes which occurred in Greece, between January 1, 2008 and June 30, 2008. In that period of time, 13 earthquakes had occurred. 6 of them were recorded with magnitudes greater than Ms=5R (5R), while 7 of them were recorded with magnitudes greater than Ms=6R (6R). Time domain feature extraction technique is applied to analyze the 1st significant changes in the earth's electric field prior to the earthquake. Two different time domain feature extraction techniques are applied in this work, namely Simple Square Integral (SSI) and Root Mean Square (RMS). The 1st significant change of the earth's electric field signal in each of monitoring sites is extracted using those two techniques. The feature extraction result can be used as input parameter for an earthquake prediction system
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Earthquake, GIS and multimedia. The 1883 Casamicciola earthquake
Directory of Open Access Journals (Sweden)
M. Rebuffat
1995-06-01
Full Text Available A series of multimedia monographs concerning the main seismic events that have affected the Italian territory are in the process of being produced for the Documental Integrated Multimedia Project (DIMP started by the Italian National Seismic Survey (NSS. The purpose of the project is to reconstruct the historical record of earthquakes and promote an earthquake public education. Producing the monographs. developed in ARC INFO and working in UNIX. involved designing a special filing and management methodology to integrate heterogeneous information (images, papers, cartographies, etc.. This paper describes the possibilities of a GIS (Geographic Information System in the filing and management of documental information. As an example we present the first monograph on the 1883 Casamicciola earthquake. on the island of Ischia (Campania, Italy. This earthquake is particularly interesting for the following reasons: I historical-cultural context (first destructive seismic event after the unification of Italy; 2 its features (volcanic earthquake; 3 the socioeconomic consequences caused at such an important seaside resort.
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OMG Earthquake! Can Twitter improve earthquake response?
Earle, P. S.; Guy, M.; Ostrum, C.; Horvath, S.; Buckmaster, R. A.
2009-12-01
The U.S. Geological Survey (USGS) is investigating how the social networking site Twitter, a popular service for sending and receiving short, public, text messages, can augment its earthquake response products and the delivery of hazard information. The goal is to gather near real-time, earthquake-related messages (tweets) and provide geo-located earthquake detections and rough maps of the corresponding felt areas. Twitter and other social Internet technologies are providing the general public with anecdotal earthquake hazard information before scientific information has been published from authoritative sources. People local to an event often publish information within seconds via these technologies. In contrast, depending on the location of the earthquake, scientific alerts take between 2 to 20 minutes. Examining the tweets following the March 30, 2009, M4.3 Morgan Hill earthquake shows it is possible (in some cases) to rapidly detect and map the felt area of an earthquake using Twitter responses. Within a minute of the earthquake, the frequency of “earthquake” tweets rose above the background level of less than 1 per hour to about 150 per minute. Using the tweets submitted in the first minute, a rough map of the felt area can be obtained by plotting the tweet locations. Mapping the tweets from the first six minutes shows observations extending from Monterey to Sacramento, similar to the perceived shaking region mapped by the USGS “Did You Feel It” system. The tweets submitted after the earthquake also provided (very) short first-impression narratives from people who experienced the shaking. Accurately assessing the potential and robustness of a Twitter-based system is difficult because only tweets spanning the previous seven days can be searched, making a historical study impossible. We have, however, been archiving tweets for several months, and it is clear that significant limitations do exist. The main drawback is the lack of quantitative information
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Earthquake Early Warning Systems
Pei-Yang Lin
2011-01-01
Because of Taiwan’s unique geographical environment, earthquake disasters occur frequently in Taiwan. The Central Weather Bureau collated earthquake data from between 1901 and 2006 (Central Weather Bureau, 2007) and found that 97 earthquakes had occurred, of which, 52 resulted in casualties. The 921 Chichi Earthquake had the most profound impact. Because earthquakes have instant destructive power and current scientific technologies cannot provide precise early warnings in advance, earthquake ...
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Aagaard, Brad T.; Brocher, T.M.; Dolenc, D.; Dreger, D.; Graves, R.W.; Harmsen, S.; Hartzell, S.; Larsen, S.; Zoback, M.L.
2008-01-01
We compute ground motions for the Beroza (1991) and Wald et al. (1991) source models of the 1989 magnitude 6.9 Loma Prieta earthquake using four different wave-propagation codes and recently developed 3D geologic and seismic velocity models. In preparation for modeling the 1906 San Francisco earthquake, we use this well-recorded earthquake to characterize how well our ground-motion simulations reproduce the observed shaking intensities and amplitude and durations of recorded motions throughout the San Francisco Bay Area. All of the simulations generate ground motions consistent with the large-scale spatial variations in shaking associated with rupture directivity and the geologic structure. We attribute the small variations among the synthetics to the minimum shear-wave speed permitted in the simulations and how they accommodate topography. Our long-period simulations, on average, under predict shaking intensities by about one-half modified Mercalli intensity (MMI) units (25%-35% in peak velocity), while our broadband simulations, on average, under predict the shaking intensities by one-fourth MMI units (16% in peak velocity). Discrepancies with observations arise due to errors in the source models and geologic structure. The consistency in the synthetic waveforms across the wave-propagation codes for a given source model suggests the uncertainty in the source parameters tends to exceed the uncertainty in the seismic velocity structure. In agreement with earlier studies, we find that a source model with slip more evenly distributed northwest and southeast of the hypocenter would be preferable to both the Beroza and Wald source models. Although the new 3D seismic velocity model improves upon previous velocity models, we identify two areas needing improvement. Nevertheless, we find that the seismic velocity model and the wave-propagation codes are suitable for modeling the 1906 earthquake and scenario events in the San Francisco Bay Area.
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Rahman, M. Moklesur; Bai, Ling; Khan, Nangyal Ghani; Li, Guohui
2018-02-01
The Himalayan-Tibetan region has a long history of devastating earthquakes with wide-spread casualties and socio-economic damages. Here, we conduct the probabilistic seismic hazard analysis by incorporating the incomplete historical earthquake records along with the instrumental earthquake catalogs for the Himalayan-Tibetan region. Historical earthquake records back to more than 1000 years ago and an updated, homogenized and declustered instrumental earthquake catalog since 1906 are utilized. The essential seismicity parameters, namely, the mean seismicity rate γ, the Gutenberg-Richter b value, and the maximum expected magnitude M max are estimated using the maximum likelihood algorithm assuming the incompleteness of the catalog. To compute the hazard value, three seismogenic source models (smoothed gridded, linear, and areal sources) and two sets of ground motion prediction equations are combined by means of a logic tree on accounting the epistemic uncertainties. The peak ground acceleration (PGA) and spectral acceleration (SA) at 0.2 and 1.0 s are predicted for 2 and 10% probabilities of exceedance over 50 years assuming bedrock condition. The resulting PGA and SA maps show a significant spatio-temporal variation in the hazard values. In general, hazard value is found to be much higher than the previous studies for regions, where great earthquakes have actually occurred. The use of the historical and instrumental earthquake catalogs in combination of multiple seismogenic source models provides better seismic hazard constraints for the Himalayan-Tibetan region.
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Yin, Lucy; Andrews, Jennifer; Heaton, Thomas
2018-05-01
Earthquake parameter estimations using nearest neighbor searching among a large database of observations can lead to reliable prediction results. However, in the real-time application of Earthquake Early Warning (EEW) systems, the accurate prediction using a large database is penalized by a significant delay in the processing time. We propose to use a multidimensional binary search tree (KD tree) data structure to organize large seismic databases to reduce the processing time in nearest neighbor search for predictions. We evaluated the performance of KD tree on the Gutenberg Algorithm, a database-searching algorithm for EEW. We constructed an offline test to predict peak ground motions using a database with feature sets of waveform filter-bank characteristics, and compare the results with the observed seismic parameters. We concluded that large database provides more accurate predictions of the ground motion information, such as peak ground acceleration, velocity, and displacement (PGA, PGV, PGD), than source parameters, such as hypocenter distance. Application of the KD tree search to organize the database reduced the average searching process by 85% time cost of the exhaustive method, allowing the method to be feasible for real-time implementation. The algorithm is straightforward and the results will reduce the overall time of warning delivery for EEW.
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Donovan, J.; Jordan, T. H.
2012-12-01
Forecasting the rupture directivity of large earthquakes is an important problem in probabilistic seismic hazard analysis (PSHA), because directivity is known to strongly influence ground motions. We describe how rupture directivity can be forecast in terms of the "conditional hypocenter distribution" or CHD, defined to be the probability distribution of a hypocenter given the spatial distribution of moment release (fault slip). The simplest CHD is a uniform distribution, in which the hypocenter probability density equals the moment-release probability density. For rupture models in which the rupture velocity and rise time depend only on the local slip, the CHD completely specifies the distribution of the directivity parameter D, defined in terms of the degree-two polynomial moments of the source space-time function. This parameter, which is zero for a bilateral rupture and unity for a unilateral rupture, can be estimated from finite-source models or by the direct inversion of seismograms (McGuire et al., 2002). We compile D-values from published studies of 65 large earthquakes and show that these data are statistically inconsistent with the uniform CHD advocated by McGuire et al. (2002). Instead, the data indicate a "centroid biased" CHD, in which the expected distance between the hypocenter and the hypocentroid is less than that of a uniform CHD. In other words, the observed directivities appear to be closer to bilateral than predicted by this simple model. We discuss the implications of these results for rupture dynamics and fault-zone heterogeneities. We also explore their PSHA implications by modifying the CyberShake simulation-based hazard model for the Los Angeles region, which assumed a uniform CHD (Graves et al., 2011).
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Twitter earthquake detection: Earthquake monitoring in a social world
Earle, Paul S.; Bowden, Daniel C.; Guy, Michelle R.
2011-01-01
The U.S. Geological Survey (USGS) is investigating how the social networking site Twitter, a popular service for sending and receiving short, public text messages, can augment USGS earthquake response products and the delivery of hazard information. Rapid detection and qualitative assessment of shaking events are possible because people begin sending public Twitter messages (tweets) with in tens of seconds after feeling shaking. Here we present and evaluate an earthquake detection procedure that relies solely on Twitter data. A tweet-frequency time series constructed from tweets containing the word "earthquake" clearly shows large peaks correlated with the origin times of widely felt events. To identify possible earthquakes, we use a short-term-average, long-term-average algorithm. When tuned to a moderate sensitivity, the detector finds 48 globally-distributed earthquakes with only two false triggers in five months of data. The number of detections is small compared to the 5,175 earthquakes in the USGS global earthquake catalog for the same five-month time period, and no accurate location or magnitude can be assigned based on tweet data alone. However, Twitter earthquake detections are not without merit. The detections are generally caused by widely felt events that are of more immediate interest than those with no human impact. The detections are also fast; about 75% occur within two minutes of the origin time. This is considerably faster than seismographic detections in poorly instrumented regions of the world. The tweets triggering the detections also provided very short first-impression narratives from people who experienced the shaking.
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Ohta, Yusaku; Hino, Ryota; Inazu, Daisuke; Ohzono, Mako; Ito, Yoshihiro; Mishina, Masaaki; Iinuma, Takeshi; Nakajima, Junichi; Osada, Yukihito; Suzuki, Kensuke; Fujimoto, Hiromi; Tachibana, Kenji; Demachi, Tomotsugu; Miura, Satoshi
2012-08-01
A magnitude 7.3 foreshock occurred at the subducting Pacific plate interface on March 9, 2011, 51 h before the magnitude 9.0 Tohoku earthquake off the Pacific coast of Japan. We propose a coseismic and postseismic afterslip model of the magnitude 7.3 event based on a global positioning system network and ocean bottom pressure gauge sites. The estimated coseismic slip and afterslip areas show complementary spatial distributions; the afterslip distribution is located up-dip of the coseismic slip for the foreshock and northward of hypocenter of the Tohoku earthquake. The slip amount for the afterslip is roughly consistent with that determined by repeating earthquake analysis carried out in a previous study. The estimated moment release for the afterslip reached magnitude 6.8, even within a short time period of 51h. A volumetric strainmeter time series also suggests that this event advanced with a rapid decay time constant compared with other typical large earthquakes.
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Testimonies to the L'Aquila earthquake (2009) and to the L'Aquila process
Kalenda, Pavel; Nemec, Vaclav
2014-05-01
Lot of confusions, misinformation, false solidarity, efforts to misuse geoethics and other unethical activities in favour of the top Italian seismologists responsible for a bad and superficial evaluation of the situation 6 days prior to the earthquake - that is a general characteristics for the whole period of 5 years separating us from the horrible morning of April 6, 2009 in L'Aquila with 309 human victims. The first author of this presentation as a seismologist had unusual opportunity to visit the unfortunate city in April 2009. He got all "first-hand" information that a real scientifically based prediction did exist already for some shocks in the area on March 29 and 30, 2009. The author of the prediction Gianpaolo Giuliani was obliged to stop any public information diffused by means of internet. A new prediction was known to him on March 31 - in the day when the "Commission of Great Risks" offered a public assurance that any immediate earthquake can be practically excluded. In reality the members of the commission completely ignored such a prediction declaring it as a false alarm of "somebody" (even without using the name of Giuliani). The observations by Giuliani were of high quality from the scientific point of view. G. Giuliani predicted L'Aquila earthquake in the professional way - for the first time during many years of observations. The anomalies, which preceded L'Aquila earthquake were detected on many places in Europe in the same time. The question is, what locality would be signed as potential focal area, if G. Giuliani would know the other observations in Europe. The deformation (and other) anomalies are observable before almost all of global M8 earthquakes. Earthquakes are preceded by deformation and are predictable. The testimony of the second author is based on many unfortunate personal experiences with representatives of the INGV Rome and their supporters from India and even Australia. In July 2010, prosecutor Fabio Picuti charged the Commission
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Earthquake Risk Mitigation in the Tokyo Metropolitan area
Hirata, N.; Sakai, S.; Kasahara, K.; Nakagawa, S.; Nanjo, K.; Panayotopoulos, Y.; Tsuruoka, H.
2010-12-01
Seismic disaster risk mitigation in urban areas constitutes a challenge through collaboration of scientific, engineering, and social-science fields. Examples of collaborative efforts include research on detailed plate structure with identification of all significant faults, developing dense seismic networks; strong ground motion prediction, which uses information on near-surface seismic site effects and fault models; earthquake resistant and proof structures; and cross-discipline infrastructure for effective risk mitigation just after catastrophic events. Risk mitigation strategy for the next greater earthquake caused by the Philippine Sea plate (PSP) subducting beneath the Tokyo metropolitan area is of major concern because it caused past mega-thrust earthquakes, such as the 1703 Genroku earthquake (magnitude M8.0) and the 1923 Kanto earthquake (M7.9) which had 105,000 fatalities. A M7 or greater (M7+) earthquake in this area at present has high potential to produce devastating loss of life and property with even greater global economic repercussions. The Central Disaster Management Council of Japan estimates that the M7+ earthquake will cause 11,000 fatalities and 112 trillion yen (about 1 trillion US$) economic loss. This earthquake is evaluated to occur with a probability of 70% in 30 years by the Earthquake Research Committee of Japan. In order to mitigate disaster for greater Tokyo, the Special Project for Earthquake Disaster Mitigation in the Tokyo Metropolitan Area (2007-2011) was launched in collaboration with scientists, engineers, and social-scientists in nationwide institutions. The results that are obtained in the respective fields will be integrated until project termination to improve information on the strategy assessment for seismic risk mitigation in the Tokyo metropolitan area. In this talk, we give an outline of our project as an example of collaborative research on earthquake risk mitigation. Discussion is extended to our effort in progress and
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Complex rupture during the 12 January 2010 Haiti earthquake
Hayes, G.P.; Briggs, R.W.; Sladen, A.; Fielding, E.J.; Prentice, C.; Hudnut, K.; Mann, P.; Taylor, F.W.; Crone, A.J.; Gold, R.; Ito, T.; Simons, M.
2010-01-01
Initially, the devastating Mw 7.0, 12 January 2010 Haiti earthquake seemed to involve straightforward accommodation of oblique relative motion between the Caribbean and North American plates along the Enriquillog-Plantain Garden fault zone. Here, we combine seismological observations, geologic field data and space geodetic measurements to show that, instead, the rupture process may have involved slip on multiple faults. Primary surface deformation was driven by rupture on blind thrust faults with only minor, deep, lateral slip along or near the main Enriquillog-Plantain Garden fault zone; thus the event only partially relieved centuries of accumulated left-lateral strain on a small part of the plate-boundary system. Together with the predominance of shallow off-fault thrusting, the lack of surface deformation implies that remaining shallow shear strain will be released in future surface-rupturing earthquakes on the Enriquillog-Plantain Garden fault zone, as occurred in inferred Holocene and probable historic events. We suggest that the geological signature of this earthquakeg-broad warping and coastal deformation rather than surface rupture along the main fault zoneg-will not be easily recognized by standard palaeoseismic studies. We conclude that similarly complex earthquakes in tectonic environments that accommodate both translation and convergenceg-such as the San Andreas fault through the Transverse Ranges of Californiag-may be missing from the prehistoric earthquake record. ?? 2010 Macmillan Publishers Limited. All rights reserved.
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Monsalve-Jaramillo, Hugo; Valencia-Mina, William; Cano-Saldaña, Leonardo; Vargas, Carlos A.
2018-05-01
Source parameters of four earthquakes located within the Wadati-Benioff zone of the Nazca plate subducting beneath the South American plate in Colombia were determined. The seismic moments for these events were recalculated and their approximate equivalent rupture area, slip distribution and stress drop were estimated. The source parameters for these earthquakes were obtained by deconvolving multiple events through teleseismic analysis of body waves recorded in long period stations and with simultaneous inversion of P and SH waves. The calculated source time functions for these events showed different stages that suggest that these earthquakes can reasonably be thought of being composed of two subevents. Even though two of the overall focal mechanisms obtained yielded similar results to those reported by the CMT catalogue, the two other mechanisms showed a clear difference compared to those officially reported. Despite this, it appropriate to mention that the mechanisms inverted in this work agree well with the expected orientation of faulting at that depth as well as with the wave forms they are expected to produce. In some of the solutions achieved, one of the two subevents exhibited a focal mechanism considerably different from the total earthquake mechanism; this could be interpreted as the result of a slight deviation from the overall motion due the complex stress field as well as the possibility of a combination of different sources of energy release analogous to the ones that may occur in deeper earthquakes. In those cases, the subevents with very different focal mechanism compared to the total earthquake mechanism had little contribution to the final solution and thus little contribution to the total amount of energy released.
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GIS Based System for Post-Earthquake Crisis Managment Using Cellular Network
Raeesi, M.; Sadeghi-Niaraki, A.
2013-09-01
Earthquakes are among the most destructive natural disasters. Earthquakes happen mainly near the edges of tectonic plates, but they may happen just about anywhere. Earthquakes cannot be predicted. Quick response after disasters, like earthquake, decreases loss of life and costs. Massive earthquakes often cause structures to collapse, trapping victims under dense rubble for long periods of time. After the earthquake and destroyed some areas, several teams are sent to find the location of the destroyed areas. The search and rescue phase usually is maintained for many days. Time reduction for surviving people is very important. A Geographical Information System (GIS) can be used for decreasing response time and management in critical situations. Position estimation in short period of time time is important. This paper proposes a GIS based system for post-earthquake disaster management solution. This system relies on several mobile positioning methods such as cell-ID and TA method, signal strength method, angel of arrival method, time of arrival method and time difference of arrival method. For quick positioning, the system can be helped by any person who has a mobile device. After positioning and specifying the critical points, the points are sent to a central site for managing the procedure of quick response for helping. This solution establishes a quick way to manage the post-earthquake crisis.
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GIS BASED SYSTEM FOR POST-EARTHQUAKE CRISIS MANAGMENT USING CELLULAR NETWORK
Directory of Open Access Journals (Sweden)
M. Raeesi
2013-09-01
Full Text Available Earthquakes are among the most destructive natural disasters. Earthquakes happen mainly near the edges of tectonic plates, but they may happen just about anywhere. Earthquakes cannot be predicted. Quick response after disasters, like earthquake, decreases loss of life and costs. Massive earthquakes often cause structures to collapse, trapping victims under dense rubble for long periods of time. After the earthquake and destroyed some areas, several teams are sent to find the location of the destroyed areas. The search and rescue phase usually is maintained for many days. Time reduction for surviving people is very important. A Geographical Information System (GIS can be used for decreasing response time and management in critical situations. Position estimation in short period of time time is important. This paper proposes a GIS based system for post–earthquake disaster management solution. This system relies on several mobile positioning methods such as cell-ID and TA method, signal strength method, angel of arrival method, time of arrival method and time difference of arrival method. For quick positioning, the system can be helped by any person who has a mobile device. After positioning and specifying the critical points, the points are sent to a central site for managing the procedure of quick response for helping. This solution establishes a quick way to manage the post–earthquake crisis.
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Variation of radon flux along active fault zones in association with earthquake occurrence
International Nuclear Information System (INIS)
Papastefanou, C.
2010-01-01
Radon flux measurements were carried out at three radon stations along an active fault zone in the Langadas basin, Northern Greece by various techniques for earthquake prediction studies. Specially made devices with alpha track-etch detectors (ATDs) were installed by using LR-115, type II, non-strippable cellulose nitrate films (integrating method of measurements). Continuous monitoring of radon gas exhaling from the ground was also performed by using silicon diode detectors, Barasol and Clipperton type, in association with various probes and sensors including simultaneously registration of the meteorological parameters, such as precipitation height (rainfall events), temperature and barometric pressure. The obtained radon data were studied in parallel with the data of seismic events, such as the magnitude, M L of earthquakes, the epicentral distance, the hypocentral distance and the energy released during the earthquake event occurred at the fault zone during the period of measurements to find out any association between the rad on flux and the meteorological and seismological parameters. Seismic events with magnitude M L ≥ 4.0 appeared to be preceded by large precursory signals produced a well-defined 'anomaly' (peak) of radon flux prior to the event. In the results, the radon peaks in the obtained spectra appeared to be sharp and narrow. The rise time of a radon peak, that is the time period from the onset of a radon peak until the time of radon flux maximum is about a week, while the after time, that is the time interval between the time of radon flux maximum and the time of a seismic event ranges from about 3 weeks or more.
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Wechsler, N.; Rockwell, T. K.; Klinger, Y.; Agnon, A.; Marco, S.
2012-12-01
Models used to forecast future seismicity make fundamental assumptions about the behavior of faults and fault systems in the long term, but in many cases this long-term behavior is assumed using short-term and perhaps non-representative observations. The question arises - how long of a record is long enough to represent actual fault behavior, both in terms of recurrence of earthquakes and of moment release (aka slip-rate). We test earthquake recurrence and slip models via high-resolution three-dimensional trenching of the Beteiha (Bet-Zayda) site on the Dead Sea Transform (DST) in northern Israel. We extend the earthquake history of this simple plate boundary fault to establish slip rate for the past 3-4kyr, to determine the amount of slip per event and to study the fundamental behavior, thereby testing competing rupture models (characteristic, slip-patch, slip-loading, and Gutenberg Richter type distribution). To this end we opened more than 900m of trenches, mapped 8 buried channels and dated more than 80 radiocarbon samples. By mapping buried channels, offset by the DST on both sides of the fault, we obtained for each an estimate of displacement. Coupled with fault crossing trenches to determine event history, we construct earthquake and slip history for the fault for the past 2kyr. We observe evidence for a total of 9-10 surface-rupturing earthquakes with varying offset amounts. 6-7 events occurred in the 1st millennium, compared to just 2-3 in the 2nd millennium CE. From our observations it is clear that the fault is not behaving in a periodic fashion. A 4kyr old buried channel yields a slip rate of 3.5-4mm/yr, consistent with GPS rates for this segment. Yet in spite of the apparent agreement between GPS, Pleistocene to present slip rate, and the lifetime rate of the DST, the past 800-1000 year period appears deficit in strain release. Thus, in terms of moment release, most of the fault has remained locked and is accumulating elastic strain. In contrast, the
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Energy Technology Data Exchange (ETDEWEB)
Kleppe, John; Norris, William; Etezadi, Mehdi
2006-07-19
This contract was awarded in response to a proposal in which a deployable plume and aerosol release prediction and tracking system would be designed, fabricated, and tested. The system would gather real time atmospheric data and input it into a real time atmospheric model that could be used for plume predition and tracking. The system would be able to be quickly deployed by aircraft to points of interest or positioned for deployment by vehicles. The system would provide three dimensional (u, v, and w) wind vector data, inversion height measurements, surface wind information, classical weather station data, and solar radiation. The on-board real time computer model would provide the prediction of the behavior of plumes and released aerosols.
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Temporal variation of gravity field prior to the Ludian Ms6.5 and Kangding Ms6.3 earthquakes
Directory of Open Access Journals (Sweden)
Hongtao Hao
2015-11-01
Full Text Available Using mobile gravity data from the central area of Sichuan and Yunnan Provinces, the relationship between gravity variation and earthquakes was studied based on the Ludian Ms6.5 earthquake that occurred on August 3rd, 2014, and the Kangding Ms6.3 earthquake that occurred on November 22nd, 2014; the mechanism of gravity variation was also explored. The results are as follows: (1 Prior to both earthquakes, gravity variation exhibited similar characteristics as those observed before both the Tangshan and Wenchuan earthquakes, in which typical precursor anomalies were positive gravity variation near the epicenter and the occurrence of a high-gravity-gradient zone across the epicenter prior to the earthquake. (2 A relatively accurate prediction of the occurrence locations of the two earthquakes was made by the Gravity Network Center of China (GNCC based on these precursor anomalies. In the gravity study report on the 2014 earthquake trends submitted at the end of 2013, the Daofu-Shimian section at the junction of the Xianshuihe and Longmenshan fault zones was noted as an earthquake-risk region with a predicted magnitude of 6.5, which covered the epicenter of the Kangding Ms6.3 earthquake. In another report on earthquake trends in southwestern China submitted in mid-2014, the Lianfeng, Zhaotong fault zone was also classified as an earthquake-risk region with a magnitude of 6.0, and the central area of this region basically overlapped with the epicenter of the Ludian Ms6.5 earthquake. (3 The gravity variation characteristics are reasonably consistent with crustal movements, and deep material migration is likely the primary cause of gravity variation.
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Initial Earthquake Centrifuge Model Experiments for the Study of Liquefaction
National Research Council Canada - National Science Library
Steedman, R
1998-01-01
.... These are intended to gather data suitable for the development of improved design approaches for the prediction of liquefaction under earthquake loading using the new centrifuge facility at the WES...
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Transpressional rupture of an unmapped fault during the 2010 Haiti earthquake
Calais, Éric
2010-10-24
On 12 January 2010, a Mw7.0 earthquake struck the Port-au-Prince region of Haiti. The disaster killed more than 200,000 people and caused an estimated $8 billion in damages, about 100% of the country?s gross domestic product. The earthquake was initially thought to have ruptured the Enriquillog-Plantain Garden fault of the southern peninsula of Haiti, which is one of two main strike-slip faults inferred to accommodate the 2cmyr -1 relative motion between the Caribbean and North American plates. Here we use global positioning system and radar interferometry measurements of ground motion to show that the earthquake involved a combination of horizontal and contractional slip, causing transpressional motion. This result is consistent with the long-term pattern of strain accumulation in Hispaniola. The unexpected contractional deformation caused by the earthquake and by the pattern of strain accumulation indicates present activity on faults other than the Enriquillog-Plantain Garden fault. We show that the earthquake instead ruptured an unmapped north-dipping fault, called the Léogâne fault. The Léogâne fault lies subparallel tog-but is different fromg-the Enriquillog-Plantain Garden fault. We suggest that the 2010 earthquake may have activated the southernmost front of the Haitian fold-and-thrust belt as it abuts against the Enriquillog-Plantain Garden fault. As the Enriquillog-Plantain Garden fault did not release any significant accumulated elastic strain, it remains a significant seismic threat for Haiti and for Port-au-Prince in particular. © 2010 Macmillan Publishers Limited. All rights reserved.
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Transpressional rupture of an unmapped fault during the 2010 Haiti earthquake
Calais, É ric; Freed, Andrew M.; Mattioli, Glen S.; Amelung, Falk; Jonsson, Sigurjon; Jansma, Pamela E.; Hong, Sanghoon; Dixon, Timothy H.; Pré petit, Claude; Momplaisir, Roberte
2010-01-01
On 12 January 2010, a Mw7.0 earthquake struck the Port-au-Prince region of Haiti. The disaster killed more than 200,000 people and caused an estimated $8 billion in damages, about 100% of the country?s gross domestic product. The earthquake was initially thought to have ruptured the Enriquillog-Plantain Garden fault of the southern peninsula of Haiti, which is one of two main strike-slip faults inferred to accommodate the 2cmyr -1 relative motion between the Caribbean and North American plates. Here we use global positioning system and radar interferometry measurements of ground motion to show that the earthquake involved a combination of horizontal and contractional slip, causing transpressional motion. This result is consistent with the long-term pattern of strain accumulation in Hispaniola. The unexpected contractional deformation caused by the earthquake and by the pattern of strain accumulation indicates present activity on faults other than the Enriquillog-Plantain Garden fault. We show that the earthquake instead ruptured an unmapped north-dipping fault, called the Léogâne fault. The Léogâne fault lies subparallel tog-but is different fromg-the Enriquillog-Plantain Garden fault. We suggest that the 2010 earthquake may have activated the southernmost front of the Haitian fold-and-thrust belt as it abuts against the Enriquillog-Plantain Garden fault. As the Enriquillog-Plantain Garden fault did not release any significant accumulated elastic strain, it remains a significant seismic threat for Haiti and for Port-au-Prince in particular. © 2010 Macmillan Publishers Limited. All rights reserved.
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Kodera, Yuki
2018-01-01
Large earthquakes with long rupture durations emit P wave energy throughout the rupture period. Incorporating late-onset P waves into earthquake early warning (EEW) algorithms could contribute to robust predictions of strong ground motion. Here I describe a technique to detect in real time P waves from growing ruptures to improve the timeliness of an EEW algorithm based on seismic wavefield estimation. The proposed P wave detector, which employs a simple polarization analysis, successfully detected P waves from strong motion generation areas of the 2011 Mw 9.0 Tohoku-oki earthquake rupture. An analysis using 23 large (M ≥ 7) events from Japan confirmed that seismic intensity predictions based on the P wave detector significantly increased lead times without appreciably decreasing the prediction accuracy. P waves from growing ruptures, being one of the fastest carriers of information on ongoing rupture development, have the potential to improve the performance of EEW systems.
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Directory of Open Access Journals (Sweden)
Anatoly V. Klyuchevskii
2013-11-01
Full Text Available The current lithospheric geodynamics and tectonophysics in the Baikal rift are discussed in terms of a nonlinear oscillator with dissipation. The nonlinear oscillator model is applicable to the area because stress change shows up as quasi-periodic inharmonic oscillations at rifting attractor structures (RAS. The model is consistent with the space-time patterns of regional seismicity in which coupled large earthquakes, proximal in time but distant in space, may be a response to bifurcations in nonlinear resonance hysteresis in a system of three oscillators corresponding to the rifting attractors. The space-time distribution of coupled MLH > 5.5 events has been stable for the period of instrumental seismicity, with the largest events occurring in pairs, one shortly after another, on two ends of the rift system and with couples of smaller events in the central part of the rift. The event couples appear as peaks of earthquake ‘migration’ rate with an approximately decadal periodicity. Thus the energy accumulated at RAS is released in coupled large events by the mechanism of nonlinear oscillators with dissipation. The new knowledge, with special focus on space-time rifting attractors and bifurcations in a system of nonlinear resonance hysteresis, may be of theoretical and practical value for earthquake prediction issues. Extrapolation of the results into the nearest future indicates the probability of such a bifurcation in the region, i.e., there is growing risk of a pending M ≈ 7 coupled event to happen within a few years.
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International Nuclear Information System (INIS)
Kobayashi, T.; Yoshikawa, K.; Takaoka, E.; Nakazawa, M.; Shikama, Y.
2002-01-01
A time history nonlinear earthquake response analysis method was proposed and applied to earthquake response prediction analysis for a Large Scale Seismic Test (LSST) Program in Hualien, Taiwan, in which a 1/4 scale model of a nuclear reactor containment structure was constructed on sandy gravel layer. In the analysis both of strain-dependent material nonlinearity, and geometrical nonlinearity by base mat uplift, were considered. The 'Lattice Model' for the soil-structure interaction model was employed. An earthquake record on soil surface at the site was used as control motion, and deconvoluted to the input motion of the analysis model at GL-52 m with 300 Gal of maximum acceleration. The following two analyses were considered: (A) time history nonlinear, (B) equivalent linear, and the advantage of time history nonlinear earthquake response analysis method is discussed
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Rethinking earthquake-related DC-ULF electromagnetic phenomena: towards a physics-based approach
Directory of Open Access Journals (Sweden)
Q. Huang
2011-11-01
Full Text Available Numerous electromagnetic changes possibly related with earthquakes have been independently reported and have even been attempted to apply to short-term prediction of earthquakes. However, there are active debates on the above issue because the seismogenic process is rather complicated and the studies have been mainly empirical (i.e. a kind of experience-based approach. Thus, a physics-based study would be helpful for understanding earthquake-related electromagnetic phenomena and strengthening their applications. As a potential physics-based approach, I present an integrated research scheme, taking into account the interaction among observation, methodology, and physical model. For simplicity, this work focuses only on the earthquake-related DC-ULF electromagnetic phenomena. The main approach includes the following key problems: (1 how to perform a reliable and appropriate observation with some clear physical quantities; (2 how to develop a robust methodology to reveal weak earthquake-related electromagnetic signals from noisy background; and (3 how to develop plausible physical models based on theoretical analyses and/or laboratory experiments for the explanation of the earthquake-related electromagnetic signals observed in the field conditions.
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Emergency feature. Great east Japan earthquake disaster Fukushima Daiichi accident
International Nuclear Information System (INIS)
Kawata, Tomio; Tsujikura, Yonezo; Kitamura, Toshiro
2011-01-01
The Tohoku Pacific Ocean earthquake occurred in March 11, 2011. The disastrous tsunami attacked Fukushima Daiichi nuclear power plants after automatically shutdown by the earthquake and all motor operated pumps became inoperable due to station black out. Despite the strenuous efforts of operators, if caused serious accident such as loss of cooling function, hydrogen explosion and release of large amount of radioactive materials into the environment, leading to nuclear power emergency that ordered resident to evacuate or remain indoors. This emergency feature consisted of four articles. The first was the interview with the president of JAIF (Japan Atomic Industrial Forum) on how to identify the cause of the accident completely, intensify safety assurance measures and promote discussions on a role of nuclear power in the nation's entire energy policy toward the reconstruction. Others were reactor states and events sequence after the accident with trend data of radiation in the reactor site, statement of president of AESJ (Atomic Energy Society of Japan) on nuclear crisis following Tohoku Pacific Ocean earthquake our response and my experience in evacuation life. (T. Tanaka)
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Foreshocks, aftershocks, and earthquake probabilities: Accounting for the landers earthquake
Jones, Lucile M.
1994-01-01
The equation to determine the probability that an earthquake occurring near a major fault will be a foreshock to a mainshock on that fault is modified to include the case of aftershocks to a previous earthquake occurring near the fault. The addition of aftershocks to the background seismicity makes its less probable that an earthquake will be a foreshock, because nonforeshocks have become more common. As the aftershocks decay with time, the probability that an earthquake will be a foreshock increases. However, fault interactions between the first mainshock and the major fault can increase the long-term probability of a characteristic earthquake on that fault, which will, in turn, increase the probability that an event is a foreshock, compensating for the decrease caused by the aftershocks.
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Diagnosis of time of increased probability of volcanic earthquakes at Mt. Vesuvius zone
Rotwain, I; Kuznetsov, I V; Panza, G F; Peresan, A
2003-01-01
The possibility of intermediate-term earthquake prediction at Mt. Vesuvius by means of the algorithm CN is explored. CN was originally designed to identify the Times of Increased Probability (TIPs) for the occurrence of strong tectonic earthquakes, with magnitude M >= M sub 0 , within a region a priori delimited. Here the algorithm CN is applied, for the first time, to the analysis of volcanic seismicity. The earthquakes recorded at Mt. Vesuvius, during the period from February 1972 to October 2002, are considered and the magnitude threshold M sub 0 , selecting the events to be predicted, is varied within the range: 3.0 - 3.3. Satisfactory prediction results are obtained, by retrospective analysis, when a time scaling is introduced. In particular, when the length of the time windows is reduced by a factor 2.5 - 3, with respect to the standard version of CN algorithm, more than 90% of the events with M >= M sub 0 occur within the TIP intervals, with TIPs occupying about 30% of the total time considered. The co...
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Vaca, Sandro; Vallée, Martin; Nocquet, Jean-Mathieu; Battaglia, Jean; Régnier, Marc
2018-01-01
The northern Ecuador segment of the Nazca/South America subduction zone shows spatially heterogeneous interseismic coupling. Two highly coupled zones (0.4° S-0.35° N and 0.8° N-4.0° N) are separated by a low coupled area, hereafter referred to as the Punta Galera-Mompiche Zone (PGMZ). Large interplate earthquakes repeatedly occurred within the coupled zones in 1958 (Mw 7.7) and 1979 (Mw 8.1) for the northern patch and in 1942 (Mw 7.8) and 2016 (Mw 7.8) for the southern patch, while the whole segment is thought to have rupture during the 1906 Mw 8.4-8.8 great earthquake. We find that during the last decade, the PGMZ has experienced regular and frequent seismic swarms. For the best documented sequence (December 2013-January 2014), a joint seismological and geodetic analysis reveals a six-week-long Slow Slip Event (SSE) associated with a seismic swarm. During this period, the microseismicity is organized into families of similar earthquakes spatially and temporally correlated with the evolution of the aseismic slip. The moment release (3.4 × 1018 Nm, Mw 6.3), over a 60 × 40 km area, is considerably larger than the moment released by earthquakes (5.8 × 1015 Nm, Mw 4.4) during the same time period. In 2007-2008, a similar seismic-aseismic episode occurred, with higher magnitudes both for the seismic and aseismic processes. Cross-correlation analyses of the seismic waveforms over a 15 years-long period further suggest a 2-year repeat time for seismic swarms, which also implies that SSEs recurrently affect this area. Such SSEs contribute to release the accumulated stress, likely explaining why the 2016 Pedernales earthquake did not propagate northward into the PGMZ.
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Energy budgets of mining-induced earthquakes and their interactions with nearby stopes
McGarr, A.
2000-01-01
In the early 1960's, N.G.W. Cook, using an underground network of geophones, demonstrated that most Witwatersrand tremors are closely associated with deep level gold mining operations. He also showed that the energy released by the closure of the tabular stopes at depths of the order of 2 km was more than sufficient to account for the mining-induced earthquakes. I report here updated versions of these two results based on more modern underground data acquired in the Witwatersrand gold fields. Firstly, an extensive suite of in situ stress data indicate that the ambient state of crustal stress here is close to the failure state in the absence of mining even though the tectonic setting is thoroughly stable. Mining initially stabilizes the rock mass by reducing the pore fluid pressure from its initial hydrostatic state to nearly zero. The extensive mine excavations, as Cook showed, concentrate the deviatoric stresses, in localized regions of the abutments, back into a failure state resulting in seismicity. Secondly, there appears to be two distinct types of mining-induced earthquakes: the first is strongly coupled to the mining and involves shear failure plus a coseismic volume reduction; the second type is not evidently coupled to any particular mine face, shows purely deviatoric failure, and is presumably caused by more regional changes in the state of stress due to mining. Thirdly, energy budgets for mining induced earthquakes of both types indicate that, of the available released energy, only a few per cent is radiated by the seismic waves with the majority being consumed in overcoming fault friction. Published by Elsevier Science Ltd.In the early 1960's, N.G.W. Cook, using an underground network of geophones, demonstrated that most Witwatersrand tremors are closely associated with deep level gold mining operations. He also showed that the energy released by the closure of the tabular stopes at depths of the order of 2 km was more than sufficient to account for the
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Recent applications for rapid estimation of earthquake shaking and losses with ELER Software
International Nuclear Information System (INIS)
Demircioglu, M.B.; Erdik, M.; Kamer, Y.; Sesetyan, K.; Tuzun, C.
2012-01-01
A methodology and software package entitled Earthquake Loss Estimation Routine (ELER) was developed for rapid estimation of earthquake shaking and losses throughout the Euro-Mediterranean region. The work was carried out under the Joint Research Activity-3 (JRA3) of the EC FP6 project entitled Network of Research Infrastructures for European Seismology (NERIES). The ELER methodology anticipates: 1) finding of the most likely location of the source of the earthquake using regional seismo-tectonic data base; 2) estimation of the spatial distribution of selected ground motion parameters at engineering bedrock through region specific ground motion prediction models, bias-correcting the ground motion estimations with strong ground motion data, if available; 3) estimation of the spatial distribution of site-corrected ground motion parameters using regional geology database using appropriate amplification models; and 4) estimation of the losses and uncertainties at various orders of sophistication (buildings, casualties). The multi-level methodology developed for real time estimation of losses is capable of incorporating regional variability and sources of uncertainty stemming from ground motion predictions, fault finiteness, site modifications, inventory of physical and social elements subjected to earthquake hazard and the associated vulnerability relationships which are coded into ELER. The present paper provides brief information on the methodology of ELER and provides an example application with the recent major earthquake that hit the Van province in the east of Turkey on 23 October 2011 with moment magnitude (Mw) of 7.2. For this earthquake, Kandilli Observatory and Earthquake Research Institute (KOERI) provided almost real time estimations in terms of building damage and casualty distribution using ELER. (author)
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Adibkia, K; Ghanbarzadeh, S; Mohammadi, G; Khiavi, H Z; Sabzevari, A; Barzegar-Jalali, M
2014-03-01
This study was conducted to investigate the effects of HPMC (K4M and K100M) as well as tragacanth on the drug release rate of diltiazem (DLTZ) from matrix tablets prepared by direct compression method.Mechanism of drug transport through the matrices was studied by fitting the release data to the 10 kinetic models. 3 model independent parameters; i. e., mean dissolution time (MDT), mean release rate (MRR) and release rate efficacy (RE) as well as 5 time point approaches were established to compare the dissolution profiles. To find correlation between fraction of drug released and polymer's molecular weight, dissolution data were fitted into two proposed equations.All polymers could sustain drug release up to 10 h. The release data were fitted best to Peppas and Higuchi square root kinetic models considering squared correlation coefficient and mean percent error (MPE). RE and MRR were decreased when polymer to drug ratio was increased. Conversely, t60% was increased with raising polymer /drug ratio. The fractions of drug released from the formulations prepared with tragacanth were more than those formulated using the same amount of HPMC K4M and HPMC K100M.Preparation of DLTZ matrices applying HPMCK4M, HPMC K100M and tragacanth could effectively extend the drug release. © Georg Thieme Verlag KG Stuttgart · New York.
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Rapid earthquake hazard and loss assessment for Euro-Mediterranean region
Erdik, Mustafa; Sesetyan, Karin; Demircioglu, Mine; Hancilar, Ufuk; Zulfikar, Can; Cakti, Eser; Kamer, Yaver; Yenidogan, Cem; Tuzun, Cuneyt; Cagnan, Zehra; Harmandar, Ebru
2010-10-01
The almost-real time estimation of ground shaking and losses after a major earthquake in the Euro-Mediterranean region was performed in the framework of the Joint Research Activity 3 (JRA-3) component of the EU FP6 Project entitled "Network of Research Infra-structures for European Seismology, NERIES". This project consists of finding the most likely location of the earthquake source by estimating the fault rupture parameters on the basis of rapid inversion of data from on-line regional broadband stations. It also includes an estimation of the spatial distribution of selected site-specific ground motion parameters at engineering bedrock through region-specific ground motion prediction equations (GMPEs) or physical simulation of ground motion. By using the Earthquake Loss Estimation Routine (ELER) software, the multi-level methodology developed for real time estimation of losses is capable of incorporating regional variability and sources of uncertainty stemming from GMPEs, fault finiteness, site modifications, inventory of physical and social elements subjected to earthquake hazard and the associated vulnerability relationships.
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Trendafiloski, G.; Gaspa Rebull, O.; Ewing, C.; Podlaha, A.; Magee, B.
2012-04-01
Calibration and validation are crucial steps in the production of the catastrophe models for the insurance industry in order to assure the model's reliability and to quantify its uncertainty. Calibration is needed in all components of model development including hazard and vulnerability. Validation is required to ensure that the losses calculated by the model match those observed in past events and which could happen in future. Impact Forecasting, the catastrophe modelling development centre of excellence within Aon Benfield, has recently launched its earthquake model for Algeria as a part of the earthquake model for the Maghreb region. The earthquake model went through a detailed calibration process including: (1) the seismic intensity attenuation model by use of macroseismic observations and maps from past earthquakes in Algeria; (2) calculation of the country-specific vulnerability modifiers by use of past damage observations in the country. The use of Benouar, 1994 ground motion prediction relationship was proven as the most appropriate for our model. Calculation of the regional vulnerability modifiers for the country led to 10% to 40% larger vulnerability indexes for different building types compared to average European indexes. The country specific damage models also included aggregate damage models for residential, commercial and industrial properties considering the description of the buildings stock given by World Housing Encyclopaedia and the local rebuilding cost factors equal to 10% for damage grade 1, 20% for damage grade 2, 35% for damage grade 3, 75% for damage grade 4 and 100% for damage grade 5. The damage grades comply with the European Macroseismic Scale (EMS-1998). The model was validated by use of "as-if" historical scenario simulations of three past earthquake events in Algeria M6.8 2003 Boumerdes, M7.3 1980 El-Asnam and M7.3 1856 Djidjelli earthquake. The calculated return periods of the losses for client market portfolio align with the
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Ionospheric earthquake precursors
International Nuclear Information System (INIS)
Bulachenko, A.L.; Oraevskij, V.N.; Pokhotelov, O.A.; Sorokin, V.N.; Strakhov, V.N.; Chmyrev, V.M.
1996-01-01
Results of experimental study on ionospheric earthquake precursors, program development on processes in the earthquake focus and physical mechanisms of formation of various type precursors are considered. Composition of experimental cosmic system for earthquake precursors monitoring is determined. 36 refs., 5 figs
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Electrical streaming potential precursors to catastrophic earthquakes in China
Directory of Open Access Journals (Sweden)
F. Qian
1997-06-01
Full Text Available The majority of anomalies in self-potential at 7 stations within 160 km from the epicentre showed a similar pattern of rapid onset and slow decay during and before the M 7.8 Tangshan earthquake of 1976. Considering that some of these anomalies associated with episodical spouting from boreholes or the increase in pore pressure in wells, observed anomalies are streaming potential generated by local events of sudden movements and diffusion process of high-pressure fluid in parallel faults. These transient events triggered by tidal forces exhibited a periodic nature and the statistical phenomenon to migrate towards the epicentre about one month before the earthquake. As a result of events, the pore pressure reached its final equilibrium state and was higher than that in the initial state in a large enough section of the fault region. Consequently, local effective shear strength of the material in the fault zone decreased and finally the catastrophic earthquake was induced. Similar phenomena also occurred one month before the M 7.3 Haichen earthquake of 1975. Therefore, a short term earthquake prediction can be made by electrical measurements, which are the kind of geophysical measurements most closely related to pore fluid behaviors of the deep crust.
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Long-term impact of earthquakes on sleep quality.
Tempesta, Daniela; Curcio, Giuseppe; De Gennaro, Luigi; Ferrara, Michele
2013-01-01
We investigated the impact of the 6.3 magnitude 2009 L'Aquila (Italy) earthquake on standardized self-report measures of sleep quality (Pittsburgh Sleep Quality Index, PSQI) and frequency of disruptive nocturnal behaviours (Pittsburgh Sleep Quality Index-Addendum, PSQI-A) two years after the natural disaster. Self-reported sleep quality was assessed in 665 L'Aquila citizens exposed to the earthquake compared with a different sample (n = 754) of L'Aquila citizens tested 24 months before the earthquake. In addition, sleep quality and disruptive nocturnal behaviours (DNB) of people exposed to the traumatic experience were compared with people that in the same period lived in different areas ranging between 40 and 115 km from the earthquake epicenter (n = 3574). The comparison between L'Aquila citizens before and after the earthquake showed a significant deterioration of sleep quality after the exposure to the trauma. In addition, two years after the earthquake L'Aquila citizens showed the highest PSQI scores and the highest incidence of DNB compared to subjects living in the surroundings. Interestingly, above-the-threshold PSQI scores were found in the participants living within 70 km from the epicenter, while trauma-related DNBs were found in people living in a range of 40 km. Multiple regressions confirmed that proximity to the epicenter is predictive of sleep disturbances and DNB, also suggesting a possible mediating effect of depression on PSQI scores. The psychological effects of an earthquake may be much more pervasive and long-lasting of its building destruction, lasting for years and involving a much larger population. A reduced sleep quality and an increased frequency of DNB after two years may be a risk factor for the development of depression and posttraumatic stress disorder.
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International Nuclear Information System (INIS)
Dan, Kazuo
2006-01-01
The Regulatory Guide for Aseismic Design of Nuclear Reactor Facilities was revised on 19 th September, 2006. Six factors for evaluation of earthquake vibration are considered on the basis of the recent earthquakes. They are 1) evaluation of earthquake vibration by method using fault model, 2) investigation and approval of active fault, 3) direct hit earthquake, 4) assumption of the short active fault as the hypocentral fault, 5) locality of the earthquake and the earthquake vibration and 6) remaining risk. A guiding principle of revision required new evaluation method of earthquake vibration using fault model, and evaluation of probability of earthquake vibration. The remaining risk means the facilities and people get into danger when stronger earthquake than the design occurred, accordingly, the scattering has to be considered at evaluation of earthquake vibration. The earthquake belt of Hyogo-Nanbu earthquake and strong vibration pulse in 1995, relation between length of surface earthquake fault and hypocentral fault, and distribution of seismic intensity of off Kushiro in 1993 are shown. (S.Y.)
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Comparison of two large earthquakes: the 2008 Sichuan Earthquake and the 2011 East Japan Earthquake.
Otani, Yuki; Ando, Takayuki; Atobe, Kaori; Haiden, Akina; Kao, Sheng-Yuan; Saito, Kohei; Shimanuki, Marie; Yoshimoto, Norifumi; Fukunaga, Koichi
2012-01-01
Between August 15th and 19th, 2011, eight 5th-year medical students from the Keio University School of Medicine had the opportunity to visit the Peking University School of Medicine and hold a discussion session titled "What is the most effective way to educate people for survival in an acute disaster situation (before the mental health care stage)?" During the session, we discussed the following six points: basic information regarding the Sichuan Earthquake and the East Japan Earthquake, differences in preparedness for earthquakes, government actions, acceptance of medical rescue teams, earthquake-induced secondary effects, and media restrictions. Although comparison of the two earthquakes was not simple, we concluded that three major points should be emphasized to facilitate the most effective course of disaster planning and action. First, all relevant agencies should formulate emergency plans and should supply information regarding the emergency to the general public and health professionals on a normal basis. Second, each citizen should be educated and trained in how to minimize the risks from earthquake-induced secondary effects. Finally, the central government should establish a single headquarters responsible for command, control, and coordination during a natural disaster emergency and should centralize all powers in this single authority. We hope this discussion may be of some use in future natural disasters in China, Japan, and worldwide.
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Energy Technology Data Exchange (ETDEWEB)
Kopytenko, Y.; Ismagilov, V. [SPbF Izmiran, St. Petersbourg (Russian Federation); Hayakawa, M [The University of Electro-Communications, Chofu, Tokyo (Japan); Smirnova, N.; Troyan, V. [St. Petersbourg Univ., St Petersbourg (Russian Federation). Inst. of Physics; Peterson, T. [TFPLAB, Cleveland, OH (United States)
2001-04-01
The results of ULF electromagnetic signal observations in seismoactive regions prior to earthquakes are presented and discussed. The new differential measurement technique developed in SPbF IZMIRAN for location of the ULF emission sources of space and lithosphere origin is described. The MVC-2DS geohphysical instrumentation is introduced as a promising tool for registration of ULF signals related to earthquakes (both seismic and electromagnetic ones). Methods are proposed for ULF data processing to investigate the preparation processes in the earthquake source regions and to distinguish seismogenic signals. on the background of space pulsations. Some examples of application of those methods for study of the earthquake precursory signatures are presented. Perspectives of seismo-electromagnetic tomography experiments in seismoactive regions, using MVC-2DS technique, are discussed in relation to the development of earthquake prediction methods.
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Changes in groundwater chemistry before two consecutive earthquakes in Iceland
Skelton, Alasdair
2014-09-21
Groundwater chemistry has been observed to change before earthquakes and is proposed as a precursor signal. Such changes include variations in radon count rates1, 2, concentrations of dissolved elements3, 4, 5 and stable isotope ratios4, 5. Changes in seismic wave velocities6, water levels in boreholes7, micro-seismicity8 and shear wave splitting9 are also thought to precede earthquakes. Precursor activity has been attributed to expansion of rock volume7, 10, 11. However, most studies of precursory phenomena lack sufficient data to rule out other explanations unrelated to earthquakes12. For example, reproducibility of a precursor signal has seldom been shown and few precursors have been evaluated statistically. Here we analyse the stable isotope ratios and dissolved element concentrations of groundwater taken from a borehole in northern Iceland between 2008 and 2013. We find that the chemistry of the groundwater changed four to six months before two greater than magnitude 5 earthquakes that occurred in October 2012 and April 2013. Statistical analyses indicate that the changes in groundwater chemistry were associated with the earthquakes. We suggest that the changes were caused by crustal dilation associated with stress build-up before each earthquake, which caused different groundwater components to mix. Although the changes we detect are specific for the site in Iceland, we infer that similar processes may be active elsewhere, and that groundwater chemistry is a promising target for future studies on the predictability of earthquakes.
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Changes in groundwater chemistry before two consecutive earthquakes in Iceland
Skelton, Alasdair; André n, Margareta; Kristmannsdó ttir, Hrefna; Stockmann, Gabrielle; Mö rth, Carl-Magnus; Sveinbjö rnsdó ttir, Á rny; Jonsson, Sigurjon; Sturkell, Erik; Guð rú nardó ttir, Helga Rakel; Hjartarson, Hreinn; Siegmund, Heike; Kockum, Ingrid
2014-01-01
Groundwater chemistry has been observed to change before earthquakes and is proposed as a precursor signal. Such changes include variations in radon count rates1, 2, concentrations of dissolved elements3, 4, 5 and stable isotope ratios4, 5. Changes in seismic wave velocities6, water levels in boreholes7, micro-seismicity8 and shear wave splitting9 are also thought to precede earthquakes. Precursor activity has been attributed to expansion of rock volume7, 10, 11. However, most studies of precursory phenomena lack sufficient data to rule out other explanations unrelated to earthquakes12. For example, reproducibility of a precursor signal has seldom been shown and few precursors have been evaluated statistically. Here we analyse the stable isotope ratios and dissolved element concentrations of groundwater taken from a borehole in northern Iceland between 2008 and 2013. We find that the chemistry of the groundwater changed four to six months before two greater than magnitude 5 earthquakes that occurred in October 2012 and April 2013. Statistical analyses indicate that the changes in groundwater chemistry were associated with the earthquakes. We suggest that the changes were caused by crustal dilation associated with stress build-up before each earthquake, which caused different groundwater components to mix. Although the changes we detect are specific for the site in Iceland, we infer that similar processes may be active elsewhere, and that groundwater chemistry is a promising target for future studies on the predictability of earthquakes.
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Scenario-based earthquake hazard and risk assessment for Baku (Azerbaijan
Directory of Open Access Journals (Sweden)
G. Babayev
2010-12-01
Full Text Available A rapid growth of population, intensive civil and industrial building, land and water instabilities (e.g. landslides, significant underground water level fluctuations, and the lack of public awareness regarding seismic hazard contribute to the increase of vulnerability of Baku (the capital city of the Republic of Azerbaijan to earthquakes. In this study, we assess an earthquake risk in the city determined as a convolution of seismic hazard (in terms of the surface peak ground acceleration, PGA, vulnerability (due to building construction fragility, population features, the gross domestic product per capita, and landslide's occurrence, and exposure of infrastructure and critical facilities. The earthquake risk assessment provides useful information to identify the factors influencing the risk. A deterministic seismic hazard for Baku is analysed for four earthquake scenarios: near, far, local, and extreme events. The seismic hazard models demonstrate the level of ground shaking in the city: PGA high values are predicted in the southern coastal and north-eastern parts of the city and in some parts of the downtown. The PGA attains its maximal values for the local and extreme earthquake scenarios. We show that the quality of buildings and the probability of their damage, the distribution of urban population, exposure, and the pattern of peak ground acceleration contribute to the seismic risk, meanwhile the vulnerability factors play a more prominent role for all earthquake scenarios. Our results can allow elaborating strategic countermeasure plans for the earthquake risk mitigation in the Baku city.
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Seismogeodesy for rapid earthquake and tsunami characterization
Bock, Y.
2016-12-01
Rapid estimation of earthquake magnitude and fault mechanism is critical for earthquake and tsunami warning systems. Traditionally, the monitoring of earthquakes and tsunamis has been based on seismic networks for estimating earthquake magnitude and slip, and tide gauges and deep-ocean buoys for direct measurement of tsunami waves. These methods are well developed for ocean basin-wide warnings but are not timely enough to protect vulnerable populations and infrastructure from the effects of local tsunamis, where waves may arrive within 15-30 minutes of earthquake onset time. Direct measurements of displacements by GPS networks at subduction zones allow for rapid magnitude and slip estimation in the near-source region, that are not affected by instrumental limitations and magnitude saturation experienced by local seismic networks. However, GPS displacements by themselves are too noisy for strict earthquake early warning (P-wave detection). Optimally combining high-rate GPS and seismic data (in particular, accelerometers that do not clip), referred to as seismogeodesy, provides a broadband instrument that does not clip in the near field, is impervious to magnitude saturation, and provides accurate real-time static and dynamic displacements and velocities in real time. Here we describe a NASA-funded effort to integrate GPS and seismogeodetic observations as part of NOAA's Tsunami Warning Centers in Alaska and Hawaii. It consists of a series of plug-in modules that allow for a hierarchy of rapid seismogeodetic products, including automatic P-wave picking, hypocenter estimation, S-wave prediction, magnitude scaling relationships based on P-wave amplitude (Pd) and peak ground displacement (PGD), finite-source CMT solutions and fault slip models as input for tsunami warnings and models. For the NOAA/NASA project, the modules are being integrated into an existing USGS Earthworm environment, currently limited to traditional seismic data. We are focused on a network of
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Ergodicity and Phase Transitions and Their Implications for Earthquake Forecasting.
Klein, W.
2017-12-01
Forecasting earthquakes or even predicting the statistical distribution of events on a given fault is extremely difficult. One reason for this difficulty is the large number of fault characteristics that can affect the distribution and timing of events. The range of stress transfer, the level of noise, and the nature of the friction force all influence the type of the events and the values of these parameters can vary from fault to fault and also vary with time. In addition, the geometrical structure of the faults and the correlation of events on different faults plays an important role in determining the event size and their distribution. Another reason for the difficulty is that the important fault characteristics are not easily measured. The noise level, fault structure, stress transfer range, and the nature of the friction force are extremely difficult, if not impossible to ascertain. Given this lack of information, one of the most useful approaches to understanding the effect of fault characteristics and the way they interact is to develop and investigate models of faults and fault systems.In this talk I will present results obtained from a series of models of varying abstraction and compare them with data from actual faults. We are able to provide a physical basis for several observed phenomena such as the earthquake cycle, thefact that some faults display Gutenburg-Richter scaling and others do not, and that some faults exhibit quasi-periodic characteristic events and others do not. I will also discuss some surprising results such as the fact that some faults are in thermodynamic equilibrium depending on the stress transfer range and the noise level. An example of an important conclusion that can be drawn from this work is that the statistical distribution of earthquake events can vary from fault to fault and that an indication of an impending large event such as accelerating moment release may be relevant on some faults but not on others.
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Twitter earthquake detection: earthquake monitoring in a social world
Directory of Open Access Journals (Sweden)
Daniel C. Bowden
2011-06-01
Full Text Available The U.S. Geological Survey (USGS is investigating how the social networking site Twitter, a popular service for sending and receiving short, public text messages, can augment USGS earthquake response products and the delivery of hazard information. Rapid detection and qualitative assessment of shaking events are possible because people begin sending public Twitter messages (tweets with in tens of seconds after feeling shaking. Here we present and evaluate an earthquake detection procedure that relies solely on Twitter data. A tweet-frequency time series constructed from tweets containing the word “earthquake” clearly shows large peaks correlated with the origin times of widely felt events. To identify possible earthquakes, we use a short-term-average, long-term-average algorithm. When tuned to a moderate sensitivity, the detector finds 48 globally-distributed earthquakes with only two false triggers in five months of data. The number of detections is small compared to the 5,175 earthquakes in the USGS global earthquake catalog for the same five-month time period, and no accurate location or magnitude can be assigned based on tweet data alone. However, Twitter earthquake detections are not without merit. The detections are generally caused by widely felt events that are of more immediate interest than those with no human impact. The detections are also fast; about 75% occur within two minutes of the origin time. This is considerably faster than seismographic detections in poorly instrumented regions of the world. The tweets triggering the detections also provided very short first-impression narratives from people who experienced the shaking.
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Li, J.; Wang, Y.; Chen, H.; Lin, L.
2013-04-01
After an earthquake, the fire risk of petrochemistry enterprises is higher than that of other enterprises as it involves production processes with inflammable and explosive characteristics. Using Chinese petrochemical enterprises as the research object, this paper uses a literature review and case summaries to study, amongst others, the classification of petrochemical enterprises, the proportion of daily fires, and fire loss ratio. This paper builds a fire following earthquake risk assessment model of petrochemical enterprises based on a previous earthquake fire hazard model, and the earthquake loss prediction assessment method, calculates the expected loss of the fire following earthquake in various counties and draws a risk map. Moreover, this research identifies high-risk areas, concentrating on the Beijing-Tianjin-Tangshan region, and Shandong, Jiangsu, and Zhejiang provinces. Differences in enterprise type produce different levels and distribution of petrochemical enterprises earthquake fire risk. Furthermore, areas at high risk of post-earthquake fires and with low levels of seismic fortification require extra attention to ensure appropriate mechanisms are in place.
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Impact of the Northridge earthquake on the mental health of veterans: results from a panel study.
Dobalian, Aram; Stein, Judith A; Heslin, Kevin C; Riopelle, Deborah; Venkatesh, Brinda; Lanto, Andrew B; Simon, Barbara; Yano, Elizabeth M; Rubenstein, Lisa V
2011-09-01
The 1994 earthquake that struck Northridge, California, led to the closure of the Veterans Health Administration Medical Center at Sepulveda. This article examines the earthquake's impact on the mental health of an existing cohort of veterans who had previously used the Sepulveda Veterans Health Administration Medical Center. From 1 to 3 months after the disaster, trained interviewers made repeated attempts to contact participants by telephone to administer a repeated measures follow-up design survey based on a survey that had been done preearthquake. Postearthquake data were obtained on 1144 of 1800 (64%) male veterans for whom there were previous data. We tested a predictive latent variable path model of the relations between sociodemographic characteristics, predisaster physical and emotional health measures, and postdisaster emotional health and perceived earthquake impact. Perceived earthquake impact was predicted by predisaster emotional distress, functional limitations, and number of health conditions. Postdisaster emotional distress was predicted by preexisting emotional distress and earthquake impact. The regression coefficient from earthquake impact to postearthquake emotional distress was larger than that of the stability coefficient from preearthquake emotional distress. Postearthquake emotional distress also was affected indirectly by preearthquake emotional distress, health conditions, younger age, and lower socioeconomic status. The postdisaster emotional health of veterans who experienced greater earthquake impact would have likely benefited from postdisaster intervention, regardless of their predisaster emotional health. Younger veterans and veterans with generally poor physical and emotional health were more vulnerable to greater postearthquake emotional distress. Veterans of lower socioeconomic status were disproportionately likely to experience more effects of the disaster because they had more predisaster emotional distress, more functional
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Paluska, A.; Pavoni, N.
1983-01-01
Research conducted for determining the location of stations for measuring crustal dynamics and predicting earthquakes is discussed. Procedural aspects, the extraregional kinematic tendencies, and regional tectonic deformation mechanisms are described.
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Lee, Ya-Ting; Turcotte, Donald L; Holliday, James R; Sachs, Michael K; Rundle, John B; Chen, Chien-Chih; Tiampo, Kristy F
2011-10-04
The Regional Earthquake Likelihood Models (RELM) test of earthquake forecasts in California was the first competitive evaluation of forecasts of future earthquake occurrence. Participants submitted expected probabilities of occurrence of M ≥ 4.95 earthquakes in 0.1° × 0.1° cells for the period 1 January 1, 2006, to December 31, 2010. Probabilities were submitted for 7,682 cells in California and adjacent regions. During this period, 31 M ≥ 4.95 earthquakes occurred in the test region. These earthquakes occurred in 22 test cells. This seismic activity was dominated by earthquakes associated with the M = 7.2, April 4, 2010, El Mayor-Cucapah earthquake in northern Mexico. This earthquake occurred in the test region, and 16 of the other 30 earthquakes in the test region could be associated with it. Nine complete forecasts were submitted by six participants. In this paper, we present the forecasts in a way that allows the reader to evaluate which forecast is the most "successful" in terms of the locations of future earthquakes. We conclude that the RELM test was a success and suggest ways in which the results can be used to improve future forecasts.
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Analysis of Earthquake Catalogs for CSEP Testing Region Italy
International Nuclear Information System (INIS)
Peresan, A.; Romashkova, L.; Nekrasova, A.; Kossobokov, V.; Panza, G.F.
2010-07-01
A comprehensive analysis shows that the set of catalogs provided by the Istituto Nazionale di Geofisica e Vulcanologia (INGV, Italy) as the authoritative database for the Collaboratory for the Study of Earthquake Predictability - Testing Region Italy (CSEP-TRI), is hardly a unified one acceptable for the necessary tuning of models/algorithms, as well as for running rigorous prospective predictability tests at intermediate- or long-term scale. (author)
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Earthquakes, September-October 1986
Person, W.J.
1987-01-01
There was one great earthquake (8.0 and above) during this reporting period in the South Pacific in the Kermadec Islands. There were no major earthquakes (7.0-7.9) but earthquake-related deaths were reported in Greece and in El Salvador. There were no destrcutive earthquakes in the United States.
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EARTHQUAKE-INDUCED DEFORMATION STRUCTURES AND RELATED TO EARTHQUAKE MAGNITUDES
Directory of Open Access Journals (Sweden)
Savaş TOPAL
2003-02-01
Full Text Available Earthquake-induced deformation structures which are called seismites may helpful to clasify the paleoseismic history of a location and to estimate the magnitudes of the potention earthquakes in the future. In this paper, seismites were investigated according to the types formed in deep and shallow lake sediments. Seismites are observed forms of sand dikes, introduced and fractured gravels and pillow structures in shallow lakes and pseudonodules, mushroom-like silts protruding laminites, mixed layers, disturbed varved lamination and loop bedding in deep lake sediments. Earthquake-induced deformation structures, by benefiting from previous studies, were ordered according to their formations and earthquake magnitudes. In this order, the lowest eartquake's record is loop bedding and the highest one is introduced and fractured gravels in lacustrine deposits.
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THE RESPONSE OF MONTEREY BAY TO THE 2010 CHILEAN EARTHQUAKE
Directory of Open Access Journals (Sweden)
Laurence C. Breaker
2011-01-01
Full Text Available The primary frequencies contained in the arrival sequence produced by the tsunami from the Chilean earthquake of 2010 in Monterey Bay were extracted to determine the seiche modes that were produced. Singular Spectrum Analysis (SSA and Ensemble Empirical Mode Decomposition (EEMD were employed to extract the primary frequencies of interest. The wave train from the Chilean tsunami lasted for at least four days due to multipath arrivals that may not have included reflections from outside the bay but most likely did include secondary undulations, and energy trapping in the form of edge waves, inside the bay. The SSA decomposition resolved oscillations with periods of 52-57, 34-35, 26-27, and 21-22 minutes, all frequencies that have been predicted and/or observed in previous studies. The EEMD decomposition detected oscillations with periods of 50-55 and 21-22 minutes. Periods in the range of 50-57 minutes varied due to measurement uncertainties but almost certainly correspond to the first longitudinal mode of oscillation for Monterey Bay, periods of 34-35 minutes correspond to the first transverse mode of oscillation that assumes a nodal line across the entrance of the bay, a period of 26- 27 minutes, although previously observed, may not represent a fundamental oscillation, and a period of 21-22 minutes has been predicted and observed previously. A period of ~37 minutes, close to the period of 34-35 minutes, was generated by the Great Alaskan Earthquake of 1964 in Monterey Bay and most likely represents the same mode of oscillation. The tsunamis associated with the Great Alaskan Earthquake and the Chilean Earthquake both entered Monterey Bay but initially arrived outside the bay from opposite directions. Unlike the Great Alaskan Earthquake, however, which excited only one resonant mode inside the bay, the Chilean Earthquake excited several modes suggesting that the asymmetric shape of the entrance to Monterey Bay was an important factor and that the
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Short-term and long-term earthquake occurrence models for Italy: ETES, ERS and LTST
Directory of Open Access Journals (Sweden)
Maura Murru
2010-11-01
Full Text Available This study describes three earthquake occurrence models as applied to the whole Italian territory, to assess the occurrence probabilities of future (M ≥5.0 earthquakes: two as short-term (24 hour models, and one as long-term (5 and 10 years. The first model for short-term forecasts is a purely stochastic epidemic type earthquake sequence (ETES model. The second short-term model is an epidemic rate-state (ERS forecast based on a model that is physically constrained by the application to the earthquake clustering of the Dieterich rate-state constitutive law. The third forecast is based on a long-term stress transfer (LTST model that considers the perturbations of earthquake probability for interacting faults by static Coulomb stress changes. These models have been submitted to the Collaboratory for the Study of Earthquake Predictability (CSEP for forecast testing for Italy (ETH-Zurich, and they were locked down to test their validity on real data in a future setting starting from August 1, 2009.
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The debate on the prognostic value of earthquake foreshocks: a meta-analysis.
Mignan, Arnaud
2014-02-14
The hypothesis that earthquake foreshocks have a prognostic value is challenged by simulations of the normal behaviour of seismicity, where no distinction between foreshocks, mainshocks and aftershocks can be made. In the former view, foreshocks are passive tracers of a tectonic preparatory process that yields the mainshock (i.e., loading by aseismic slip) while in the latter, a foreshock is any earthquake that triggers a larger one. Although both processes can coexist, earthquake prediction is plausible in the first case while virtually impossible in the second. Here I present a meta-analysis of 37 foreshock studies published between 1982 and 2013 to show that the justification of one hypothesis or the other depends on the selected magnitude interval between minimum foreshock magnitude m(min) and mainshock magnitude M. From this literature survey, anomalous foreshocks are found to emerge when m(min) < M - 3.0. These results suggest that a deviation from the normal behaviour of seismicity may be observed only when microseismicity is considered. These results are to be taken with caution since the 37 studies do not all show the same level of reliability. These observations should nonetheless encourage new research in earthquake predictability with focus on the potential role of microseismicity.
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Seismic activity prediction using computational intelligence techniques in northern Pakistan
Asim, Khawaja M.; Awais, Muhammad; Martínez-Álvarez, F.; Iqbal, Talat
2017-10-01
Earthquake prediction study is carried out for the region of northern Pakistan. The prediction methodology includes interdisciplinary interaction of seismology and computational intelligence. Eight seismic parameters are computed based upon the past earthquakes. Predictive ability of these eight seismic parameters is evaluated in terms of information gain, which leads to the selection of six parameters to be used in prediction. Multiple computationally intelligent models have been developed for earthquake prediction using selected seismic parameters. These models include feed-forward neural network, recurrent neural network, random forest, multi layer perceptron, radial basis neural network, and support vector machine. The performance of every prediction model is evaluated and McNemar's statistical test is applied to observe the statistical significance of computational methodologies. Feed-forward neural network shows statistically significant predictions along with accuracy of 75% and positive predictive value of 78% in context of northern Pakistan.
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Megathrust earthquakes in Central Chile: What is next after the Maule 2010 earthquake?
Madariaga, R.
2013-05-01
The 27 February 2010 Maule earthquake occurred in a well identified gap in the Chilean subduction zone. The event has now been studied in detail using both far-field, near field seismic and geodetic data, we will review this information gathered so far. The event broke a region that was much longer along strike than the gap left over from the 1835 Concepcion earthquake, sometimes called the Darwin earthquake because he was in the area when the earthquake occurred and made many observations. Recent studies of contemporary documents by Udias et al indicate that the area broken by the Maule earthquake in 2010 had previously broken by a similar earthquake in 1751, but several events in the magnitude 8 range occurred in the area principally in 1835 already mentioned and, more recently on 1 December 1928 to the North and on 21 May 1960 (1 1/2 days before the big Chilean earthquake of 1960). Currently the area of the 2010 earthquake and the region immediately to the North is undergoing a very large increase in seismicity with numerous clusters of seismicity that move along the plate interface. Examination of the seismicity of Chile of the 18th and 19th century show that the region immediately to the North of the 2010 earthquake broke in a very large megathrust event in July 1730. this is the largest known earthquake in central Chile. The region where this event occurred has broken in many occasions with M 8 range earthquakes in 1822, 1880, 1906, 1971 and 1985. Is it preparing for a new very large megathrust event? The 1906 earthquake of Mw 8.3 filled the central part of the gap but it has broken again on several occasions in 1971, 1973 and 1985. The main question is whether the 1906 earthquake relieved enough stresses from the 1730 rupture zone. Geodetic data shows that most of the region that broke in 1730 is currently almost fully locked from the northern end of the Maule earthquake at 34.5°S to 30°S, near the southern end of the of the Mw 8.5 Atacama earthquake of 11
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One feature of the activated southern Ordos block: the Ziwuling small earthquake cluster
Directory of Open Access Journals (Sweden)
Li Yuhang
2014-08-01
Full Text Available Small earthquakes (Ms > 2.0 have been recorded from 1970 to the present day and reveal a significant difference in seismicity between the stable Ordos block and its active surrounding area. The southern Ordos block is a conspicuous small earthquake belt clustered and isolated along the NNW direction and extends to the inner stable Ordos block; no active fault can match this small earthquake cluster. In this paper, we analyze the dynamic mechanism of this small earthquake cluster based on the GPS velocity field (from 1999 to 2007, which are mainly from Crustal Movement Observation Network of China (CMONOC with respect to the north and south China blocks. The principal direction of strain rate field, the expansion ratefield, the maximum shear strain rate, and the rotation rate were constrained using the GPS velocity field. The results show that the velocity field, which is bounded by the small earthquake cluster from Tongchuan to Weinan, differs from the strain rate field, and the crustal deformation is left-lateral shear. This left-lateral shear belt not only spatially coincides with the Neo-tectonic belt in the Weihe Basin but also with the NNW small earthquake cluster (the Ziwuling small earthquake cluster. Based on these studies, we speculate that the NNW small earthquake cluster is caused by left-lateral shear slip, which is prone to strain accumulation. When the strain releases along the weak zone of structure, small earthquakes diffuse within its upper crust. The maximum principal compression strees direction changed from NE-SW to NEE-SWW, and the former reverse faults in the southwestern margin of the Ordos block became a left-lateral strike slip due to readjustment of the tectonic strees field after the middle Pleistocene. The NNW Neo-tectonic belt in the Weihe Basin, the different movement character of the inner Weihe Basin (which was demonstrated through GPS measurements and the small earthquake cluster belt reflect the activated
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Directory of Open Access Journals (Sweden)
Muhammad Auchar Zardari
2017-01-01
Full Text Available Much of the seismic activity of northern Sweden consists of micro-earthquakes occurring near postglacial faults. However, larger magnitude earthquakes do occur in Sweden, and earthquake statistics indicate that a magnitude 5 event is likely to occur once every century. This paper presents dynamic analyses of the effects of larger earthquakes on an upstream tailings dam at the Aitik copper mine in northern Sweden. The analyses were performed to evaluate the potential for liquefaction and to assess stability of the dam under two specific earthquakes: a commonly occurring magnitude 3.6 event and a more extreme earthquake of magnitude 5.8. The dynamic analyses were carried out with the finite element program PLAXIS using a recently implemented constitutive model called UBCSAND. The results indicate that the magnitude 5.8 earthquake would likely induce liquefaction in a limited zone located below the ground surface near the embankment dikes. It is interpreted that stability of the dam may not be affected due to the limited extent of the liquefied zone. Both types of earthquakes are predicted to induce tolerable magnitudes of displacements. The results of the postseismic slope stability analysis, performed for a state after a seismic event, suggest that the dam is stable during both the earthquakes.
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Wu, Stephen; Beck, James L.
2012-04-01
Earthquake early warning (EEW) systems are currently operating nationwide in Japan and are in beta-testing in California. Such a system detects an earthquake initiation using online signals from a seismic sensor network and broadcasts a warning of the predicted location and magnitude a few seconds to a minute or so before an earthquake hits a site. Such a system can be used synergistically with installed structural health monitoring (SHM) systems to enhance pre-event prognosis and post-event diagnosis of structural health. For pre-event prognosis, the EEW system information can be used to make probabilistic predictions of the anticipated damage to a structure using seismic loss estimation methodologies from performance-based earthquake engineering. These predictions can support decision-making regarding the activation of appropriate mitigation systems, such as stopping traffic from entering a bridge that has a predicted high probability of damage. Since the time between warning and arrival of the strong shaking is very short, probabilistic predictions must be rapidly calculated and the decision making automated for the mitigation actions. For post-event diagnosis, the SHM sensor data can be used in Bayesian updating of the probabilistic damage predictions with the EEW predictions as a prior. Appropriate Bayesian methods for SHM have been published. In this paper, we use pre-trained surrogate models (or emulators) based on machine learning methods to make fast damage and loss predictions that are then used in a cost-benefit decision framework for activation of a mitigation measure. A simple illustrative example of an infrastructure application is presented.
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Sugimoto, M.
2016-12-01
Risk communication is a big issues among seismologists after the 2009 L'Aquila earthquake all over the world. A lot of people remember 7 researchers as "L'Aquila 7" were accused in Italy. Seismologists said it is impossible to predict an earthquake by science technology today and join more outreach activities. "In a subsequent inquiry of the handling of the disaster, seven members of the Italian National Commission for the Forecast and Prevention of Major Risks were accused of giving "inexact, incomplete and contradictory" information about the danger of the tremors prior to the main quake. On 22 October 2012, six scientists and one ex-government official were convicted of multiple manslaughter for downplaying the likelihood of a major earthquake six days before it took place. They were each sentenced to six years' imprisonment (Wikipedia)". Finally 6 scientists are not guilty. The 2016 Kumamoto earthquake hit Kyushu, Japan in April. They are very similar seismological situations between the 2016 Kumamoto earthquake and the 2009 L'Aquila earthquake. The foreshock was Mj6.5 and Mw6.2 in 14 April 2016. The main shock was Mj7.3 and Mw7.0. Japan Metrological Agency (JMA) misleaded foreshock as mainshock before main shock occured. 41 people died by the main shock in Japan. However local people did not accused scientists in Japan. It has been less big earhquakes around 100 years in Kumamoto. Poeple was not so matured that they treated earthquake information in Kyushu, Japan. How are there differences between Japan and Italy? We learn about outreach activities for sciencits from this case.
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Extreme value statistics and thermodynamics of earthquakes. Large earthquakes
Energy Technology Data Exchange (ETDEWEB)
Lavenda, B. [Camerino Univ., Camerino, MC (Italy); Cipollone, E. [ENEA, Centro Ricerche Casaccia, S. Maria di Galeria, RM (Italy). National Centre for Research on Thermodynamics
2000-06-01
A compound Poisson process is used to derive a new shape parameter which can be used to discriminate between large earthquakes and aftershocks sequences. Sample exceedance distributions of large earthquakes are fitted to the Pareto tail and the actual distribution of the maximum to the Frechet distribution, while the sample distribution of aftershocks are fitted to a Beta distribution and the distribution of the minimum to the Weibull distribution for the smallest value. The transition between initial sample distributions and asymptotic extreme value distributions show that self-similar power laws are transformed into non scaling exponential distributions so that neither self-similarity nor the Gutenberg-Richter law can be considered universal. The energy-magnitude transformation converts the Frechet distribution into the Gumbel distribution, originally proposed by Epstein and Lomnitz, and not the Gompertz distribution as in the Lomnitz-Adler and Lomnitz generalization of the Gutenberg-Richter law. Numerical comparison is made with the Lomnitz-Adler and Lomnitz analysis using the same catalogue of Chinese earthquakes. An analogy is drawn between large earthquakes and high energy particle physics. A generalized equation of state is used to transform the Gamma density into the order-statistic Frechet distribution. Earthquake temperature and volume are determined as functions of the energy. Large insurance claims based on the Pareto distribution, which does not have a right endpoint, show why there cannot be a maximum earthquake energy.
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Precursory changes in seismic velocity for the spectrum of earthquake failure modes
Scuderi, M.M.; Marone, C.; Tinti, E.; Di Stefano, G.; Collettini, C.
2016-01-01
Temporal changes in seismic velocity during the earthquake cycle have the potential to illuminate physical processes associated with fault weakening and connections between the range of fault slip behaviors including slow earthquakes, tremor and low frequency earthquakes1. Laboratory and theoretical studies predict changes in seismic velocity prior to earthquake failure2, however tectonic faults fail in a spectrum of modes and little is known about precursors for those modes3. Here we show that precursory changes of wave speed occur in laboratory faults for the complete spectrum of failure modes observed for tectonic faults. We systematically altered the stiffness of the loading system to reproduce the transition from slow to fast stick-slip and monitored ultrasonic wave speed during frictional sliding. We find systematic variations of elastic properties during the seismic cycle for both slow and fast earthquakes indicating similar physical mechanisms during rupture nucleation. Our data show that accelerated fault creep causes reduction of seismic velocity and elastic moduli during the preparatory phase preceding failure, which suggests that real time monitoring of active faults may be a means to detect earthquake precursors. PMID:27597879
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Activated Very Low Frequency Earthquakes By the Slow Slip Events in the Ryukyu Subduction Zone
Nakamura, M.; Sunagawa, N.
2014-12-01
The Ryukyu Trench (RT), where the Philippine Sea plate is subducting, has had no known thrust earthquakes with a Mw>8.0 in the last 300 years. However, the rupture source of the 1771 tsunami has been proposed as an Mw > 8.0 earthquake in the south RT. Based on the dating of tsunami boulders, it has been estimated that large tsunamis occur at intervals of 150-400 years in the south Ryukyu arc (RA) (Araoka et al., 2013), although they have not occurred for several thousand years in the central and northern Ryukyu areas (Goto et al., 2014). To address the discrepancy between recent low moment releases by earthquakes and occurrence of paleo-tsunamis in the RT, we focus on the long-term activity of the very low frequency earthquakes (VLFEs), which are good indicators of the stress release in the shallow plate interface. VLFEs have been detected along the RT (Ando et al., 2012), which occur on the plate interface or at the accretionary prism. We used broadband data from the F-net of NIED along the RT and from the IRIS network. We applied two filters to all the raw broadband seismograms: a 0.02-0.05 Hz band-pass filter and a 1 Hz high-pass filter. After identification of the low-frequency events from the band-pass-filtered seismograms, the local and teleseismic events were removed. Then we picked the arrival time of the maximum amplitude of the surface wave of the VLFEs and determined the epicenters. VLFEs occurred on the RA side within 100 km from the trench axis along the RT. Distribution of the 6670 VLFEs from 2002 to 2013 could be divided to several clusters. Principal large clusters were located at 27.1°-29.0°N, 25.5°-26.6°N, and 122.1°-122.4°E (YA). We found that the VLFEs of the YA are modulated by repeating slow slip events (SSEs) which occur beneath south RA. The activity of the VLFEs increased to two times of its ordinary rate in 15 days after the onset of the SSEs. Activation of the VLFEs could be generated by low stress change of 0.02-20 kPa increase in
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Earthquakes, November-December 1977
Person, W.J.
1978-01-01
Two major earthquakes occurred in the last 2 months of the year. A magnitude 7.0 earthquake struck San Juan Province, Argentina, on November 23, causing fatalities and damage. The second major earthquake was a magnitude 7.0 in the Bonin Islands region, an unpopulated area. On December 19, Iran experienced a destructive earthquake, which killed over 500.
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Attention bias in earthquake-exposed survivors: an event-related potential study.
Zhang, Yan; Kong, Fanchang; Han, Li; Najam Ul Hasan, Abbasi; Chen, Hong
2014-12-01
The Chinese Wenchuan earthquake, which happened on the 28th of May in 2008, may leave deep invisible scars in individuals. China has a large number of children and adolescents, who tend to be most vulnerable because they are in an early stage of human development and possible post-traumatic psychological distress may have a life-long consequence. Trauma survivors without post-traumatic stress disorder (PTSD) have received little attention in previous studies, especially in event-related potential (ERP) studies. We compared the attention bias to threat stimuli between the earthquake-exposed group and the control group in a masked version of the dot probe task. The target probe presented at the same space location consistent with earthquake-related words was the congruent trial, while in the space location of neutral words was the incongruent trial. Thirteen earthquake-exposed middle school students without PTSD and 13 matched controls were included in this investigation. The earthquake-exposed group showed significantly faster RTs to congruent trials than to incongruent trials. The earthquake-exposed group produced significantly shorter C1 and P1 latencies and larger C1, P1 and P2 amplitudes than the control group. In particular, enhanced P1 amplitude to threat stimuli was observed in the earthquake-exposed group. These findings are in agreement with the prediction that earthquake-exposed survivors have an attention bias to threat stimuli. The traumatic event had a much greater effect on earthquake-exposed survivors even if they showed no PTSD symptoms than individuals in the controls. These results will provide neurobiological evidences for effective intervention and prevention to post-traumatic mental problems. Copyright © 2014 Elsevier B.V. All rights reserved.
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Protecting your family from earthquakes: The seven steps to earthquake safety
Developed by American Red Cross, Asian Pacific Fund
2007-01-01
This book is provided here because of the importance of preparing for earthquakes before they happen. Experts say it is very likely there will be a damaging San Francisco Bay Area earthquake in the next 30 years and that it will strike without warning. It may be hard to find the supplies and services we need after this earthquake. For example, hospitals may have more patients than they can treat, and grocery stores may be closed for weeks. You will need to provide for your family until help arrives. To keep our loved ones and our community safe, we must prepare now. Some of us come from places where earthquakes are also common. However, the dangers of earthquakes in our homelands may be very different than in the Bay Area. For example, many people in Asian countries die in major earthquakes when buildings collapse or from big sea waves called tsunami. In the Bay Area, the main danger is from objects inside buildings falling on people. Take action now to make sure your family will be safe in an earthquake. The first step is to read this book carefully and follow its advice. By making your home safer, you help make our community safer. Preparing for earthquakes is important, and together we can make sure our families and community are ready. English version p. 3-13 Chinese version p. 14-24 Vietnamese version p. 25-36 Korean version p. 37-48
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Earthquake Triggering in the September 2017 Mexican Earthquake Sequence
Fielding, E. J.; Gombert, B.; Duputel, Z.; Huang, M. H.; Liang, C.; Bekaert, D. P.; Moore, A. W.; Liu, Z.; Ampuero, J. P.
2017-12-01
Southern Mexico was struck by four earthquakes with Mw > 6 and numerous smaller earthquakes in September 2017, starting with the 8 September Mw 8.2 Tehuantepec earthquake beneath the Gulf of Tehuantepec offshore Chiapas and Oaxaca. We study whether this M8.2 earthquake triggered the three subsequent large M>6 quakes in southern Mexico to improve understanding of earthquake interactions and time-dependent risk. All four large earthquakes were extensional despite the the subduction of the Cocos plate. The traditional definition of aftershocks: likely an aftershock if it occurs within two rupture lengths of the main shock soon afterwards. Two Mw 6.1 earthquakes, one half an hour after the M8.2 beneath the Tehuantepec gulf and one on 23 September near Ixtepec in Oaxaca, both fit as traditional aftershocks, within 200 km of the main rupture. The 19 September Mw 7.1 Puebla earthquake was 600 km away from the M8.2 shock, outside the standard aftershock zone. Geodetic measurements from interferometric analysis of synthetic aperture radar (InSAR) and time-series analysis of GPS station data constrain finite fault total slip models for the M8.2, M7.1, and M6.1 Ixtepec earthquakes. The early M6.1 aftershock was too close in time and space to the M8.2 to measure with InSAR or GPS. We analyzed InSAR data from Copernicus Sentinel-1A and -1B satellites and JAXA ALOS-2 satellite. Our preliminary geodetic slip model for the M8.2 quake shows significant slip extended > 150 km NW from the hypocenter, longer than slip in the v1 finite-fault model (FFM) from teleseismic waveforms posted by G. Hayes at USGS NEIC. Our slip model for the M7.1 earthquake is similar to the v2 NEIC FFM. Interferograms for the M6.1 Ixtepec quake confirm the shallow depth in the upper-plate crust and show centroid is about 30 km SW of the NEIC epicenter, a significant NEIC location bias, but consistent with cluster relocations (E. Bergman, pers. comm.) and with Mexican SSN location. Coulomb static stress
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Energy Technology Data Exchange (ETDEWEB)
Shi, H. (Seismological Brigade of Beijing, China); Cai, Z.; Gao, M.
1980-02-01
The character and cause of blowing out of gases and emission of sound from dry wells and of water becoming muddy and changing of level in water wells of the Beijing region immediately before the 1976 Tangshan earthquake and its strong aftershocks are investigated. These phenomena, taken as possible precursors of the earthquakes as well as the motivating force, mechanism, geological background and material sources of the anomalous migration are discussed. Besides, the paper also deals with the relation between these anomalies and the Tangshan earthquake and the significance of the study of groundwater as far as earthquake prediction is concerned. No gaseous gushing from great depth in considerable quantities appeared so that migration should be regarded only as the migration of shallow groundwater and gases. This is referred to the consequence of the action on certain hydrogeological structures of an impulse-like extra tectonic stress field on the active faults in the Beijing region under a unified regional stress field. The present authors suppose that further studies of the anomalous migration of groundwater and gases possibly may be fruitful to earthquake prediction work.
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Energy Technology Data Exchange (ETDEWEB)
Shi, H.; Cai, Z.; Gao, M.
1980-02-01
The character and cause of blowing out of gases and emission of sound from dry wells and of water becoming muddy and changing of level in water wells of the Beijing region immediately before the 1976 Tangshan earthquake and its strong aftershocks are investigated. These phenomena, taken as possible precursors of the earthquakes as well as the motivating force, mechanism, geological background and material sources of the anomalous migration, are discussed. In addition, the paper also deals with the relation between these anomalies and the Tangshan earthquake and the significance of the study of groundwater as far as earthquake prediction is concerned. No gaseous gushing from great depth in considerable quantities appeared so that migration should be regarded only as the migration of shallow groundwater and gases. This is referred to as the consequence of the action on certain hydrogeological structures of an impulse-like extra tectonic stress field on the active faults in the Beijing region under a unified regional stress field. The present authors suppose that further studies of the anomalous migration of groundwater and gases possibly may be fruitful to earthquake prediction work.
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Evidence for strong Holocene earthquake(s) in the Wabash Valley seismic zone
International Nuclear Information System (INIS)
Obermeier, S.
1991-01-01
Many small and slightly damaging earthquakes have taken place in the region of the lower Wabash River Valley of Indiana and Illinois during the 200 years of historic record. Seismologists have long suspected the Wabash Valley seismic zone to be capable of producing earthquakes much stronger than the largest of record (m b 5.8). The seismic zone contains the poorly defined Wabash Valley fault zone and also appears to contain other vaguely defined faults at depths from which the strongest earthquakes presently originate. Faults near the surface are generally covered with thick alluvium in lowlands and a veneer of loess in uplands, which make direct observations of faults difficult. Partly because of this difficulty, a search for paleoliquefaction features was begun in 1990. Conclusions of the study are as follows: (1) an earthquake much stronger than any historic earthquake struck the lower Wabash Valley between 1,500 and 7,500 years ago; (2) the epicentral region of the prehistoric strong earthquake was the Wabash Valley seismic zone; (3) apparent sites have been located where 1811-12 earthquake accelerations can be bracketed
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Leveraging geodetic data to reduce losses from earthquakes
Murray, Jessica R.; Roeloffs, Evelyn A.; Brooks, Benjamin A.; Langbein, John O.; Leith, William S.; Minson, Sarah E.; Svarc, Jerry L.; Thatcher, Wayne R.
2018-04-23
event response products and by expanded use of geodetic imaging data to assess fault rupture and source parameters.Uncertainties in the NSHM, and in regional earthquake models, are reduced by fully incorporating geodetic data into earthquake probability calculations.Geodetic networks and data are integrated into the operations and earthquake information products of the Advanced National Seismic System (ANSS).Earthquake early warnings are improved by more rapidly assessing ground displacement and the dynamic faulting process for the largest earthquakes using real-time geodetic data.Methodology for probabilistic earthquake forecasting is refined by including geodetic data when calculating evolving moment release during aftershock sequences and by better understanding the implications of transient deformation for earthquake likelihood.A geodesy program that encompasses a balanced mix of activities to sustain missioncritical capabilities, grows new competencies through the continuum of fundamental to applied research, and ensures sufficient resources for these endeavors provides a foundation by which the EHP can be a leader in the application of geodesy to earthquake science. With this in mind the following objectives provide a framework to guide EHP efforts:Fully utilize geodetic information to improve key products, such as the NSHM and EEW, and to address new ventures like the USGS Subduction Zone Science Plan.Expand the variety, accuracy, and timeliness of post-earthquake information products, such as PAGER (Prompt Assessment of Global Earthquakes for Response), through incorporation of geodetic observations.Determine if geodetic measurements of transient deformation can significantly improve estimates of earthquake probability.Maintain an observational strategy aligned with the target outcomes of this document that includes continuous monitoring, recording of ephemeral observations, focused data collection for use in research, and application-driven data processing and
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Hough, S.E.; Page, M.
2011-01-01
At the heart of the conundrum of seismogenesis in the New Madrid Seismic Zone is the apparently substantial discrepancy between low strain rate and high recent seismic moment release. In this study we revisit the magnitudes of the four principal 1811–1812 earthquakes using intensity values determined from individual assessments from four experts. Using these values and the grid search method of Bakun and Wentworth (1997), we estimate magnitudes around 7.0 for all four events, values that are significantly lower than previously published magnitude estimates based on macroseismic intensities. We further show that the strain rate predicted from postglacial rebound is sufficient to produce a sequence with the moment release of one Mmax6.8 every 500 years, a rate that is much lower than previous estimates of late Holocene moment release. However, Mw6.8 is at the low end of the uncertainty range inferred from analysis of intensities for the largest 1811–1812 event. We show that Mw6.8 is also a reasonable value for the largest main shock given a plausible rupture scenario. One can also construct a range of consistent models that permit a somewhat higher Mmax, with a longer average recurrence rate. It is thus possible to reconcile predicted strain and seismic moment release rates with alternative models: one in which 1811–1812 sequences occur every 500 years, with the largest events being Mmax∼6.8, or one in which sequences occur, on average, less frequently, with Mmax of ∼7.0. Both models predict that the late Holocene rate of activity will continue for the next few to 10 thousand years.
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Earthquake likelihood model testing
Schorlemmer, D.; Gerstenberger, M.C.; Wiemer, S.; Jackson, D.D.; Rhoades, D.A.
2007-01-01
INTRODUCTIONThe Regional Earthquake Likelihood Models (RELM) project aims to produce and evaluate alternate models of earthquake potential (probability per unit volume, magnitude, and time) for California. Based on differing assumptions, these models are produced to test the validity of their assumptions and to explore which models should be incorporated in seismic hazard and risk evaluation. Tests based on physical and geological criteria are useful but we focus on statistical methods using future earthquake catalog data only. We envision two evaluations: a test of consistency with observed data and a comparison of all pairs of models for relative consistency. Both tests are based on the likelihood method, and both are fully prospective (i.e., the models are not adjusted to fit the test data). To be tested, each model must assign a probability to any possible event within a specified region of space, time, and magnitude. For our tests the models must use a common format: earthquake rates in specified “bins” with location, magnitude, time, and focal mechanism limits.Seismology cannot yet deterministically predict individual earthquakes; however, it should seek the best possible models for forecasting earthquake occurrence. This paper describes the statistical rules of an experiment to examine and test earthquake forecasts. The primary purposes of the tests described below are to evaluate physical models for earthquakes, assure that source models used in seismic hazard and risk studies are consistent with earthquake data, and provide quantitative measures by which models can be assigned weights in a consensus model or be judged as suitable for particular regions.In this paper we develop a statistical method for testing earthquake likelihood models. A companion paper (Schorlemmer and Gerstenberger 2007, this issue) discusses the actual implementation of these tests in the framework of the RELM initiative.Statistical testing of hypotheses is a common task and a
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Prevalence and predictors of stress disorders following two earthquakes.
Yuan, Kang Chuan; Ruo Yao, Zhao; Zhen Yu, Shi; Xu Dong, Zhao; Jian Zhong, Yang; Edwards, Jason Glen; Edwards, Glen David
2013-09-01
Studies about stress disorders following a disaster have mainly been based on single-event trauma with little emphasis on multiple traumas. This study investigated the prevalence and predictors of stress disorders following two earthquakes in China. Subjects were randomly sampled from 11 villages in rural China. A total of 624 subjects were administered with the 12-item General Health Questionnaire (GHQ-12), Symptom Checklist -90-R (SCL-90-R), Coping Style Scale and Social Support Rating Scale. This was followed by a structural clinical interview using the Chinese translation of the Structured Clinical Interview for Diagnostic and Statistical Manual (DSM)-IV-TR axis 1 disorders (SCID-I-P) for acute stress disorder (ASD) and post-traumatic stress disorder (PTSD). The prevalence of ASD and PTSD was 15% and 29%, respectively. Regression analysis indicated that high intensity of trauma exposure, lower educational level, subjective feeling of economic status and psychological stress after the first earthquake significantly predicted the outcome of PTSD. The study suggested that the prevalence of stress disorders in two earthquakes were higher than that experienced in a single disaster. The intensity of trauma exposure, low educational level, bad subjective feeling of economic status, and psychological stress after the first earthquake could be used to identify survivors at risk of developing PTSD in two earthquakes.
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Strong motion modeling at the Paducah Diffusion Facility for a large New Madrid earthquake
International Nuclear Information System (INIS)
Herrmann, R.B.
1991-01-01
The Paducah Diffusion Facility is within 80 kilometers of the location of the very large New Madrid earthquakes which occurred during the winter of 1811-1812. Because of their size, seismic moment of 2.0 x 10 27 dyne-cm or moment magnitude M w = 7.5, the possible recurrence of these earthquakes is a major element in the assessment of seismic hazard at the facility. Probabilistic hazard analysis can provide uniform hazard response spectra estimates for structure evaluation, but a deterministic modeling of a such a large earthquake can provide strong constraints on the expected duration of motion. The large earthquake is modeled by specifying the earthquake fault and its orientation with respect to the site, and by specifying the rupture process. Synthetic time histories, based on forward modeling of the wavefield, from each subelement are combined to yield a three component time history at the site. Various simulations are performed to sufficiently exercise possible spatial and temporal distributions of energy release on the fault. Preliminary results demonstrate the sensitivity of the method to various assumptions, and also indicate strongly that the total duration of ground motion at the site is controlled primarily by the length of the rupture process on the fault
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How complete is the ISC-GEM Global Earthquake Catalog?
Michael, Andrew J.
2014-01-01
The International Seismological Centre, in collaboration with the Global Earthquake Model effort, has released a new global earthquake catalog, covering the time period from 1900 through the end of 2009. In order to use this catalog for global earthquake studies, I determined the magnitude of completeness (Mc) as a function of time by dividing the earthquakes shallower than 60 km into 7 time periods based on major changes in catalog processing and data availability and applying 4 objective methods to determine Mc, with uncertainties determined by non-parametric bootstrapping. Deeper events were divided into 2 time periods. Due to differences between the 4 methods, the final Mc was determined subjectively by examining the features that each method focused on in both the cumulative and binned magnitude frequency distributions. The time periods and Mc values for shallow events are: 1900-1917, Mc=7.7; 1918-1939, Mc=7.0; 1940-1954, Mc=6.8; 1955-1963, Mc=6.5; 1964-1975, Mc=6.0; 1976-2003, Mc=5.8; and 2004-2009, Mc=5.7. Using these Mc values for the longest time periods they are valid for (e.g. 1918-2009, 1940-2009,…) the shallow data fits a Gutenberg-Richter distribution with b=1.05 and a=8.3, within 1 standard deviation, with no declustering. The exception is for time periods that include 1900-1917 in which there are only 33 events with M≥ Mc and for those few data b=2.15±0.46. That result calls for further investigations for this time period, ideally having a larger number of earthquakes. For deep events, the results are Mc=7.1 for 1900-1963, although the early data are problematic; and Mc=5.7 for 1964-2009. For that later time period, b=0.99 and a=7.3.
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The Need for More Earthquake Science in Southeast Asia
Sieh, K.
2015-12-01
Many regions within SE Asia have as great a density of active seismic structures as does the western US - Sumatra, Myanmar, Bangladesh, New Guinea and the Philippines come first to mind. Much of Earth's release of seismic energy in the current millennium has, in fact, come from these regions, with great losses of life and livelihoods. Unfortunately, the scientific progress upon which seismic-risk reduction in SE Asia ultimately depends has been and continues to be slow. Last year at AGU, for example, I counted 57 talks about the M6 Napa earthquake. In contrast, I can't recall hearing any talk on a SE Asian M6 earthquake at any venue in the past many years. In fact, even M7+ earthquakes often go unstudied. Not uncommonly, the region's earthquake scientists face high financial and political impediments to conducting earthquake research. Their slow speed in the development of scientific knowledge doesn't bode well for speedy progress in the science of seismic hazards, the sine qua non for substantially reducing seismic risk. There are two basic necessities for the region to evolve significantly from the current state of affairs. Both involve the development of regional infrastructure: 1) Data: Robust and accessible geophysical monitoring systems would need to be installed, maintained and utilized by the region's earth scientists and their results shared internationally. Concomitantly, geological mapping (sensu lato) would need to be undertaken. 2) People: The training, employment, and enduring support of a new, young, international corps of earth scientists would need to accelerate markedly. The United States could play an important role in achieving the goal of significant seismic risk reduction in the most seismically active countries of SE Asia by taking the lead in establishing a coalition to robustly fund a multi-decadal program that supports scientists and their research institutions to work alongside local expertise.
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Geochemical variation of groundwater in the Abruzzi region: earthquakes related signals?
Cardellini, C.; Chiodini, G.; Caliro, S.; Frondini, F.; Avino, R.; Minopoli, C.; Morgantini, N.
2009-12-01
The presence of a deep and inorganic source of CO2 has been recently recognized in Italy on the basis of the deeply derived carbon dissolved in the groundwater. In particular, the regional map of CO2 Earth degassing shows that two large degassing structures affect the Tyrrhenian side of the Italian peninsula. The northern degassing structure (TRDS, Tuscan Roman degassing structure) includes Tuscany, Latium and part of Umbria regions (~30000 km2) and releases > 6.1 Mt/y of deeply derived CO2. The southern degassing structure (CDS, Campanian degassing structure) affects the Campania region (~10000 km2) and releases > 3.1 Mt/y of deeply derived CO2. The total CO2 released by TRDS and CDS (> 9.2 Mt/y) is globally significant, being ~10% of the estimated present-day total CO2 discharge from sub aerial volcanoes of the Earth. The comparison between the map of CO2 Earth degassing and of the location of the Italian earthquakes highlights that the anomalous CO2 flux suddenly disappears in the Apennine in correspondence of a narrow band where most of the seismicity concentrates. A previous conceptual model proposed that in this area, at the eastern borders of TRDS and CDS plumes, the CO2 from the mantle wedge intrudes the crust and accumulate in structural traps generating over-pressurized reservoirs. These CO2 over-pressurized levels can play a major role in triggering the Apennine earthquakes, by reducing fault strength and potentially controlling the nucleation, arrest, and recurrence of both micro and major (M>5) earthquakes. The 2009 Abruzzo earthquakes, like previous seismic crises in the Northern Apennine, occurred at the border of the TRDS, suggesting also in this case a possible role played by deeply derived fluids in the earthquake generation. In order to investigate this process, detailed hydro-geochemical campaigns started immediately after the main shock of the 6th of April 2009. The surveys include the main springs of the area which were previously studied in
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Predicting speech release from masking through spatial separation in distance
DEFF Research Database (Denmark)
Chabot-Leclerc, Alexandre; Dau, Torsten
2014-01-01
of spatial release from masking (SRM) where the masker is moved, on-axis, away from the target. Two binaural models, which use the conventional audio signal-to-noise ratio (SNR) in the decision metric, and two monaural models, using a decision metric based on the SNR in the envelope domain (SNRenv), were...... considered. The predictions were compared to data from Westermann et al. [2013, POMA, 19, 050156] in condi- tions where the target was located 0.5 m in front of the listener and the masker was presented at a distance of 0.5, 2, 5 or 10 m in front of the listener. The data showed an SRM of 10 dB when moving...... the masker from a distance of 0.5 m to a distance of 10 m. The long-term monaural model based on the SNRenv metric was able to account for most of the SRM data, whereas the models that used the audio SNR did not predict any SRM, even when they included an equalizationcancellation-like process. The short...
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Wang, Yan; Lu, Yi
2018-01-01
The objective of this study is to explore the relationship between earthquake exposure and the incidence of PTSD. A stratification random sample survey was conducted to collect data in the Longmenshan thrust fault after Lushan earthquake three years. We used the Children's Revised Impact of Event Scale (CRIES-13) and the Earthquake Experience Scale. Subjects in this study included 3944 school student survivors in local eleven schools. The prevalence of probable PTSD is relatively higher, when the people was trapped in the earthquake, was injured in the earthquake or have relatives who died in the earthquake. It concluded that researchers need to pay more attention to the children and adolescents. The government should pay more attention to these people and provide more economic support.
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Salditch, L.; Brooks, E. M.; Stein, S.; Spencer, B. D.; Campbell, M. R.
2017-12-01
A challenge for earthquake hazard assessment is that geologic records often show large earthquakes occurring in temporal clusters separated by periods of quiescence. For example, in Cascadia, a paleoseismic record going back 10,000 years shows four to five clusters separated by approximately 1,000 year gaps. If we are still in the cluster that began 1700 years ago, a large earthquake is likely to happen soon. If the cluster has ended, a great earthquake is less likely. For a Gaussian distribution of recurrence times, the probability of an earthquake in the next 50 years is six times larger if we are still in the most recent cluster. Earthquake hazard assessments typically employ one of two recurrence models, neither of which directly incorporate clustering. In one, earthquake probability is time-independent and modeled as Poissonian, so an earthquake is equally likely at any time. The fault has no "memory" because when a prior earthquake occurred has no bearing on when the next will occur. The other common model is a time-dependent earthquake cycle in which the probability of an earthquake increases with time until one happens, after which the probability resets to zero. Because the probability is reset after each earthquake, the fault "remembers" only the last earthquake. This approach can be used with any assumed probability density function for recurrence times. We propose an alternative, Long-Term Fault Memory (LTFM), a modified earthquake cycle model where the probability of an earthquake increases with time until one happens, after which it decreases, but not necessarily to zero. Hence the probability of the next earthquake depends on the fault's history over multiple cycles, giving "long-term memory". Physically, this reflects an earthquake releasing only part of the elastic strain stored on the fault. We use the LTFM to simulate earthquake clustering along the San Andreas Fault and Cascadia. In some portions of the simulated earthquake history, events would
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Crowdsourced earthquake early warning
Minson, Sarah E.; Brooks, Benjamin A.; Glennie, Craig L.; Murray, Jessica R.; Langbein, John O.; Owen, Susan E.; Heaton, Thomas H.; Iannucci, Robert A.; Hauser, Darren L.
2015-01-01
Earthquake early warning (EEW) can reduce harm to people and infrastructure from earthquakes and tsunamis, but it has not been implemented in most high earthquake-risk regions because of prohibitive cost. Common consumer devices such as smartphones contain low-cost versions of the sensors used in EEW. Although less accurate than scientific-grade instruments, these sensors are globally ubiquitous. Through controlled tests of consumer devices, simulation of an Mw (moment magnitude) 7 earthquake on California’s Hayward fault, and real data from the Mw 9 Tohoku-oki earthquake, we demonstrate that EEW could be achieved via crowdsourcing.
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Revisiting the November 27, 1945 Makran (Mw=8.2) interplate earthquake
Zarifi, Z.; Raeesi, M.
2012-04-01
Makran Subduction Zone (MSZ) in southern Iran and southwestern Pakistan is a zone of convergence, where the remnant oceanic crust of Arabian plate is subducting beneath the Eurasian plate with a rate of less than 30 mm/yr. The November 27, 1945 earthquake (Mw=8.2) in eastern section of Makran followed by a tsunami, at some points 15 meters high. More than 4000 victims and widespread devastation along the coastal area of Pakistan, Iran, Oman and India are reported for this earthquake. We have collected the old seismograms of the 1945 earthquake and its largest following earthquake (August 5, 1947, Mw=7.3) from a number of stations around the globe. Using ISS data, we relocated these two events. We used the teleseismic body-waveform inversion code of Kikuchi and Kanamori to determine the slip distribution of these two earthquakes for the first time. The results show that the extent of rupture of the 1945 earthquake is larger than what previously had been approximated in other studies. The slip distribution suggests two distinct sets of asperities with different behavior in the west close to Pasni and in the east close to Ormara. The highest slip was obtained for an area between these two cities which shows geological evidence of rapid uplift. To associate this behavior with the structure of slab interface we studied the TPGA (Trench Parallel Free-air Gravity Anomaly) and TPBA (Trench Parallel Bouguer Anomaly) in MSZ. The results of TPGA does not show the expected phenomenon, which is the correlation of asperities with the area of highly negative TPGA. However, TPBA can make correlation between the observed slip distribution and the structure of slab interface. Using the topography and gravity profiles perpendicular to trench and along the MSZ, we could observe the segmentation in the slab interface. This confirms that we barely expect that the whole interface releases energy in one single megathrust earthquake. Current seismicity in MSZ, although sparse, can fairly
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Encyclopedia of earthquake engineering
Kougioumtzoglou, Ioannis; Patelli, Edoardo; Au, Siu-Kui
2015-01-01
The Encyclopedia of Earthquake Engineering is designed to be the authoritative and comprehensive reference covering all major aspects of the science of earthquake engineering, specifically focusing on the interaction between earthquakes and infrastructure. The encyclopedia comprises approximately 265 contributions. Since earthquake engineering deals with the interaction between earthquake disturbances and the built infrastructure, the emphasis is on basic design processes important to both non-specialists and engineers so that readers become suitably well-informed without needing to deal with the details of specialist understanding. The content of this encyclopedia provides technically inclined and informed readers about the ways in which earthquakes can affect our infrastructure and how engineers would go about designing against, mitigating and remediating these effects. The coverage ranges from buildings, foundations, underground construction, lifelines and bridges, roads, embankments and slopes. The encycl...