Sample records for m6 wells earthquake

  1. Global Positioning System constraints on crustal deformation before and during the 21 February 2008 Wells, Nevada M6.0 earthquake (United States)

    Hammond, William C.; Blewitt, Geoffrey; Kreemer, Corné; Murray-Moraleda, Jessica R.; Svarc, Jerry L.; dePolo, Craig M.; LaPointe, Daphne D.


    Using Global Positioning System (GPS) data from permanent sites and U.S. Geological Survey (USGS) campaign data we have estimated co-seismic displacements and secular background crustal deformation patterns associated with the 21 February 2008 Wells Nevada earthquake. Estimated displacements at nearby permanent GPS sites ELKO (84 km distant) and GOSH (81 km distant) are 1.0±0.2 mm and 1.1±0.3 mm, respectively. The magnitude and direction are in agreement with those predicted from a rupture model based on InSAR measurements of the near-field co-seismic surface displacement. Analysis of long GPS time series (>10 years) from the permanent sites within 250 km of the epicenter indicate the eastern Nevada Basin and Range undergoes steady tectonic transtension with rates on the order of 1 mm/year over approximately 250 km. The azimuth of maximum horizontal crustal extension is consistent with the azimuth of the Wells earthquake co-seismic slip vector. The orientation of crustal shear is consistent with deformation associated with Pacific/North America plate boundary relative motion seen elsewhere in the Basin and Range. In response to the event, we deployed a new GPS site with the capability to telemeter high rate, low latency data that will in the future allow for rapid estimation of surface displacement should aftershocks or postseismic deformations occur. We estimated co-seismic displacements using campaign GPS data collected before and after the event, however in most cases their uncertainties were larger than the offsets. Better precision in co-seismic displacement could have been achieved for the campaign sites if they had been surveyed more times or over a longer interval to better estimate their pre-event velocity.

  2. Early aftershock decay rate of the M6 Parkfield earthquake (United States)

    Peng, Z.; Vidale, J. E.


    Mainshock rupture is typically followed by its aftershocks that diminish in rate approximately as the reciprocal of the elapse time. However, it is notoriously difficult to observe aftershock activity in the noisy aftermath of larger earthquakes. Many aftershocks were missed in the existing seismicity catalogs in the initial few minutes (Kagan, 2004). Yet this period holds valuable information about the transition from mainshock rupture to sporadic aftershocks, and the friction laws that control earthquakes. The Parkfield section of the San Andreas fault is one of most densely seismometered places in the world. Many near-fault, non-clipped and continuous recordings of the M6 Parkfield earthquake and its aftermath have been recovered, providing an excellent opportunity for us to study the aftershock decay rates in the first few hundred seconds after the mainshock. We have so far analyzed recordings from station PKD and 13 stations in the Parkfield High Resolution Seismic Network. By scrutinizing the high-frequency signal, we are able to distinguish mainshock coda from early aftershocks. We find up to 10 times more aftershocks in the first 1000 s than in the USGS NCSN catalog. More than 30 events are detected in the first 200 s after the mainshock. None of these events are in the USGS NCSN catalog. Preliminary results suggest a strong deficit of aftershocks in the first 100 s after the mainshock relative to a 1/t aftershock rate decay. This pattern is consistent with a lack of seismicity in the first 120 s following the 10/31/2001 M5.1 Anza earthquake (Kilb et al., 2004), and our study of early aftershock rates using data from HiNet array in Japan (Vidale et al., 2004). Our observations will allow us to test the prediction of such an interval in rate-and-state friction models prior to the onset of the 1/t aftershock decay rate (Dieterich, 1994).

  3. The ShakeMaps of the Amatrice, M6, earthquake

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    Licia Faenza


    Full Text Available In this paper we describe the performance of the ShakeMap software package and the fully automatic procedure, based on manually revised location and magnitude, during the main event of the Amatrice sequence with special emphasis to the M6 main shock, that struck central Italy on the 24th August 2016 at 1:36:32 UTC. Our results show that the procedure we developed in the last years, with real-time data exchange among those institutions acquiring strong motion data, allows to provide a faithful description of the ground motion experienced throughout a large region in and around the epicentral  area. The prompt availability of the rupture fault model, within three hours after the earthquake occurrence, provided a better descriptions of the level of strong ground motion throughout the affected area.  Progressive addition of  station data and  manual verification of the data insures improvements in the description of the experienced ground motions.  In particular, comparison between the MCS intensity shakemaps and preliminary field macroseismic reports show favourable similarities.  Finally the overall  spatial pattern of the ground motion of the main shock is consistent with reported rupture directivity toward NW and reduced levels of ground shaking toward SW probably linked to the peculiar source effects of the earthquake.

  4. The Characteristic Analysis and Seismic Triggering Study of the M6.2 and M6.1 Dayao Earthquake Sequences in 2003

    Institute of Scientific and Technical Information of China (English)

    Hua Wei; Liu Jie; Zheng Sihua; Chen Zhangli


    The high-resolution hypocenter locations of the mainshocks on July 21 (M6.2) and October 16, 2003 ( M6.1 ) and their aftershock sequences are determined in Dayao, Yunnan by using a double-difference earthquake location algorithm. The results show that the epicenters of the two mainshocks are very close to each other and the distribution of the aftershock sequence appears to be very linear. The distribution of the earthquake sequence is very consistent with the focal mechanism, and both malnshocks are of nearly vertical right-lateral fault. Unlike most other double earthquakes in the Yunnan area, the aftershock distribution of the M6.2 and M6.1 Dayao earthquakes does not appear to be a conjugated distribution but to be in a line, and there are some stacks in the two earthquake sequences. It can be inferred that they are all controlled by the same fault. The distribution of aftershocks is asymmetrical with respect to the mainshock location and appears to be unilateral. The aftershocks of the M6.2 mainshock centralize in the northwest of M6.2 earthquake and the aftershocks of the M6.1 earthquake are in the southeast of the mainshock, moreover, the M6.1 earthquake appears to be another rupture on the southeastern extension of the same fault as the M6.2 earthquake. The results of Coulomb failure static stress changes Aσf show that the earthquake on July 21 (M6.2) apparently triggered the earthquake on October 16 (M6.1), the two mainshocks have stress triggering to their off-fault aftershocks to different extents, and the M6.5 earthquake that occurred in Yao'an in 2000 also triggered the occurrence of the two Dayao earthquakes.

  5. Study on S wave splitting in Dayao earthquake sequence with M=6.2 and M=6.1 in Yunnan in 2003

    Institute of Scientific and Technical Information of China (English)

    HUA Wei; LIU Jie; CHEN Zhang-li; ZHENG Si-hua


    The polarization direction of fast wave and the delay time between fast and slow wave were measured for two earthquake sequences occurred continuously on 21 July (M=6.2) and 16 October (M=6.1) in Dayao, Yunnan in 2003 using cross-correlation coefficient method, after determining the high-resolution hypocentral locations of the phenomena of S wave splitting are obvious in the two earthquake sequences, and the average polarization directions of fast wave in most stations are almost consistent with regional maximum horizontal compressive stress direction except the station Santai. There are bimodal fast directions in the polarization directions at station Santai and the mean polarization direction is N80°E, indicating an inconsistent phenomenon referred to regional maxiparison of S wave splitting results in the two earthquake sequences show that the polarization direction in M=6.2earthquake sequence is more scattered and its average fast direction is 20° larger than that of M=6.1 sequence, and zation direction may be due to the stress disturbance imposed by the M=6.2 and the M=6.1 mainshocks on regional background stress field.

  6. Seismomagnetic effects from the long-awaited 28 September 2004 M 6.0 parkfield earthquake (United States)

    Johnston, M.J.S.; Sasai, Y.; Egbert, G.D.; Mueller, R.J.


    Precise measurements of local magnetic fields have been obtained with a differentially connected array of seven synchronized proton magnetometers located along 60 km of the locked-to-creeping transition region of the San Andreas fault at Parkfield, California, since 1976. The M 6.0 Parkfield earthquake on 28 September 2004, occurred within this array and generated coseismic magnetic field changes of between 0.2 and 0.5 nT at five sites in the network. No preseismic magnetic field changes exceeding background noise levels are apparent in the magnetic data during the month, week, and days before the earthquake (or expected in light of the absence of measurable precursive deformation, seismicity, or pore pressure changes). Observations of electric and magnetic fields from 0.01 to 20 Hz are also made at one site near the end of the earthquake rupture and corrected for common-mode signals from the ionosphere/magnetosphere using a second site some 115 km to the northwest along the fault. These magnetic data show no indications of unusual noise before the earthquake in the ULF band (0.01-20 Hz) as suggested may have preceded the 1989 ML 7.1 Loma Prieta earthquake. Nor do we see electric field changes similar to those suggested to occur before earthquakes of this magnitude from data in Greece. Uniform and variable slip piezomagnetic models of the earthquake, derived from strain, displacement, and seismic data, generate magnetic field perturbations that are consistent with those observed by the magnetometer array. A higher rate of longer-term magnetic field change, consistent with increased loading in the region, is apparent since 1993. This accompanied an increased rate of secular shear strain observed on a two-color EDM network and a small network of borehole tensor strainmeters and increased seismicity dominated by three M 4.5-5 earthquakes roughly a year apart in 1992, 1993, and 1994. Models incorporating all of these data indicate increased slip at depth in the region

  7. Seismomagnetic Effects from the Long-awaited September 28, 2004, M6 Parkfield Earthquake (United States)

    Johnston, M. J.; Sasai, Y.; Egbert, G. D.; Kappler, K.


    Precise measurements of local magnetic fields have been obtained with a differentially connected array of seven synchronized proton magnetometers located along 60 km of the locked-to-creeping transition region of the San Andreas Fault at Parkfield, CA. since 1984. The M6 Parkfield earthquake on September 28, 2004, occurred within this array and generated coseismic magnetic field changes of between 0.2 and 0.5 nT at five sites in the network. No preseismic magnetic field changes exceeding background noise levels are apparent in the magnetic data during the month, week and days before the earthquake (or expected in light of the absence of measurable precursive deformation, seismicity or pore pressure changes). Observations of electric and magnetic fields from 0.01 to 20 Hz are also made at one site near the end of the earthquake rupture and corrected for common-mode signals from the ionosphere/magnetosphere using a second site some 115 km to the northwest along the fault. These magnetic data show no indications of unusual noise before the earthquake in the ULF band (0.01 Hz to 20 Hz) as suggested may have preceded the 1989 Loma Prieta earthquake. Nor do we see electric field changes similar to those believed to occur before earthquakes of this magnitude from data in Greece. Uniform and variable slip piezomagnetic models of the earthquake, derived from strain, displacement and seismic data, generates magnetic field perturbations that are consistent with those observed by the magnetometer array. A higher rate of longer-term magnetic field change, consistent with increased loading in the region, is apparent since 1993. This accompanied an increased rate of secular shear strain observed on a 2-color EDM network and a small network of borehole tensor strainmeters and increased seismicity dominated by three M4.5-5 earthquakes roughly a year apart in 1992, 1993 and 1994. Models incorporating all of these data indicate increased slip at depth in the region and this may have

  8. How to predict Italy L'Aquila M6.3 earthquake (United States)

    Guo, Guangmeng


    According to the satellite cloud anomaly appeared over eastern Italy on 21-23 April 2012, we predicted the M6.0 quake occurred in north Italy successfully. Here checked the satellite images in 2011-2013 in Italy, and 21 cloud anomalies were found. Their possible correlation with earthquakes bigger than M4.7 which located in Italy main fault systems was statistically examined by assuming various lead times. The result shows that when the leading time interval is set to 23≤ΔT≤45 days, 8 of the 10 quakes were preceded by cloud anomalies. Poisson random test shows that AAR (anomaly appearance rate) and EOR (EQ occurrence rate) is much higher than the values by chance. This study proved the relation between cloud anomaly and earthquake in Italy. With this method, we found that L'Aquila earthquake can also be predicted according to cloud anomaly.

  9. Characteristics of crustal strain associated with M=6.4 Baotou earthquake in 1996

    Institute of Scientific and Technical Information of China (English)

    郭良迁; 薄万举; 胡新康; 王敏


    Based on the horizontal crustal strain derived from GPS data and the rate accumulation intensity calculated from across-fault vertical deformation, the strain characteristics in the periods of 1992~1995, 1995~1996 and 1996~1999 in Baotou-Datong area is studied in the paper. From the comparison between the crustal strains before and after the M=6.4 Baotou earthquake occurred on May 3, 1996, it is considered that the high-magnitude area with predominant compressive strain might be the seismogenic zone for a coming strong earthquake. The area with the simultaneous higher surface strain, principal compressive strain, shear strain and tendency accumulation might be the place with higher risk of strong earthquakes. Generally, the area with low strain and predominant tensile strain might have a small possibility for strong earthquake development, which belongs to a stable area. The evolution of horizontal strain obtained from GPS measurements carried out in Baotou-Datong area in the period of 1992~1999 reflects the total developing and ending processes of the seismic episode from 1996 to 1998. The area with high and predominant compressive strain and the strain gradient zone can be considered as one of the indicators for determining the strong earthquake risk area in the future.

  10. Near-Field Deformation Associated with the South Napa Earthquake (M 6.0) Using Differential Airborne LiDAR (United States)

    Hudnut, K. W.; Glennie, C. L.; Brooks, B. A.; Hauser, D. L.; Ericksen, T.; Boatwright, J.; Rosinski, A.; Dawson, T. E.; Mccrink, T. P.; Mardock, D. K.; Hoirup, D. F., Jr.; Bray, J.


    Pre-earthquake airborne LiDAR coverage exists for the area impacted by the M 6.0 South Napa earthquake. The Napa watershed data set was acquired in 2003, and data sets were acquired in other portions of the impacted area in 2007, 2010 and 2014. The pre-earthquake data are being assessed and are of variable quality and point density. Following the earthquake, a coalition was formed to enable rapid acquisition of post-earthquake LiDAR. Coordination of this coalition took place through the California Earthquake Clearinghouse; consequently, a commercial contract was organized by Department of Water Resources that allowed for the main fault rupture and damaged Browns Valley area to be covered 16 days after the earthquake at a density of 20 points per square meter over a 20 square kilometer area. Along with the airborne LiDAR, aerial imagery was acquired and will be processed to form an orthomosaic using the LiDAR-derived DEM. The 'Phase I' airborne data were acquired using an Optech Orion M300 scanner, an Applanix 200 GPS-IMU, and a DiMac ultralight medium format camera by Towill. These new data, once delivered, will be differenced against the pre-earthquake data sets using a newly developed algorithm for point cloud matching, which is improved over prior methods by accounting for scan geometry error sources. Proposed additional 'Phase II' coverage would allow repeat-pass, post-earthquake coverage of the same area of interest as in Phase I, as well as an addition of up to 4,150 square kilometers that would potentially allow for differential LiDAR assessment of levee and bridge impacts at a greater distance from the earthquake source. Levee damage was reported up to 30 km away from the epicenter, and proposed LiDAR coverage would extend up to 50 km away and cover important critical lifeline infrastructure in the western Sacramento River delta, as well as providing full post-earthquake repeat-pass coverage of the Napa watershed to study transient deformation.

  11. Apply ETAS in Earthquake Early Warning - A case study of M6.0 South Napa Earthquake (United States)

    Yin, L.; Heaton, T. H.


    Earthquake Early Warning (EEW) is a trade-off between time and accuracy. We aim to increase the alerting time without loosing its reliability. This can be achieved by using prior information to classify a pick to be a true or false event, then issue alerts immediately after the first trigger. Since earthquakes cluster in time and location, potential aftershock occurrences can be predicted using the Epidemic-Type Aftershock Sequence Model (ETAS). We show that by applying the prior information provided by ETAS in the Bayesian updating process of EEW, we can significantly improve the alerting time. As an example, the epicenter estimation for the aftershock events from the M6.0 South Napa Earthquake is performed using ETAS to illustrate the accuracy of aftershock prediction. For instance, in an aftershock sequence, the most triggers at the closest stations will turn out to be real earthquake. As a result, during the aftershock sequence of the South Napa earthquake, warnings can be issued after observations of only one or two stations.

  12. Stress-based aftershock forecasting: the 2008 M=7.9 Wenchuan, and 2013 M=6.6 Lushan earthquakes (United States)

    Parsons, T.


    Immediately after the 12 May 2008 M=7.9 Wenchuan earthquake, static stress change calculations were made on the on major faults surrounding the rupture zone. The purpose was two-fold: (1) to identify the most likely locations (stress increases) of dangerous aftershocks, and (2) to conduct a prospective test of stress mapping as a rapid-response forecast tool. The occurrence of the 20 April M=6.6 Lushan earthquake in the Longmen fault zone near Ya'an was consistent with the static stress forecast, but a formal evaluation of the post Wenchuan forecast performance was not favorable because the anticipated aftershock distribution was violated, with clear seismicity rate increases in stress shadow zones. Here I look at reconciling these results and ask the question, are static stress change calculations more applicable to larger aftershocks? A single case such as the Wenchuan-Lushan pairing could readily be a coincidence, so I look at additional large continental earthquakes and their aftershock magnitude relations. Results show (1) the most probable place that high magnitude aftershocks will occur is in areas with the highest aftershock activity, (2) high magnitude aftershocks are most likely to happen where stress change calculations are greatest, and (3) high magnitude aftershocks are most likely to happen on well developed fault zones. All three of these points are fairly obvious, but a conclusion that can be drawn from the 2008 M=7.9 Wenchuan and 2013 M=6.6 Lushon pair is that all three are necessary considerations. The location of the 2013 M=6.6 Lushon earthquake was consistent with stress change calculations, although there was virtually no precursory activity in the immediate vicinity. Therefore a forecast based only on elevated activity rates would not have anticipated its location.

  13. Jet streams anomalies as possible short-term precursors of earthquakes with M>6.0

    Directory of Open Access Journals (Sweden)

    Hong-Chun Wu


    Full Text Available Satellite data of thermal images revealed the existence of thermal fields, connected with big linear structures and systems of crust faults. The measuring height of outgoing longwave radiation is located to the range of jet stream. This work describes a possible link between strong earthquakes and jet streams in two regions. The front or tail ends of jet groups maintain their position for 6 or more hours in the vicinity of epicenters of strong (M>6.0 earthquakes in 2006-2010. The probability of observing a stationary jet stream behavior is estimated in 93.6% of the cases on one sixhour map and in 26.7% of cases - on two adjacent maps. The median of distribution of distances between epicenters and the relevant positions of jet stream corresponds to 36.5 km. Estimates of cumulative probability of realization of prediction were 24.2% for 10 days, 48.4% for 20 days, 66.1% for 30 days, 87.1% for 40 days, 93.5% for 50 days and 100% during 70 days. The observed precursory effects are of considerable interest for possible use for real short-term prediction of earthquakes.

  14. E-DECIDER Rapid Response to the M 6.0 South Napa Earthquake (United States)

    Glasscoe, M. T.; Parker, J. W.; Pierce, M. E.; Wang, J.; Eguchi, R. T.; Huyck, C. K.; Hu, Z.; Chen, Z.; Yoder, M. R.; Rundle, J. B.; Rosinski, A.


    E-DECIDER initiated rapid response mode when the California Earthquake Clearinghouse was activated the morning following the M6 Napa earthquake. Data products, including: 1) rapid damage and loss estimates, 2) deformation magnitude and slope change maps, and 3) aftershock forecasts were provided to the Clearinghouse partners within 24 hours of the event via XchangeCore Web Service Data Orchestration sharing. NASA data products were provided to end-users via XchangeCore, EERI and Clearinghouse websites, and ArcGIS online for Napa response, reaching a wide response audience. The E-DECIDER team helped facilitate rapid delivery of NASA products to stakeholders and participated in Clearinghouse Napa earthquake briefings to update stakeholders on product information. Rapid response products from E-DECIDER can be used to help prioritize response efforts shortly after the event has occurred. InLET (Internet Loss Estimation Tool) post-event damage and casualty estimates were generated quickly after the Napa earthquake. InLET provides immediate post-event estimates of casualties and building damage by performing loss/impact simulations using USGS ground motion data and FEMA HAZUS damage estimation technology. These results were provided to E-DECIDER by their collaborators, ImageCat, Inc. and the Community Stakeholder Network (CSN). Strain magnitude and slope change maps were automatically generated when the Napa earthquake appeared on the USGS feed. These maps provide an early estimate of where the deformation has occurred and where damage may be localized. Using E-DECIDER critical infrastructure overlays with damage estimates, decision makers can direct response effort that can be verified later with field reconnaissance and remote sensing-based observations. Earthquake aftershock forecast maps were produced within hours of the event. These maps highlight areas where aftershocks are likely to occur and can also be coupled with infrastructure overlays to help direct response

  15. California Earthquake Clearinghouse Activation for August 24, 2014, M6.0 South Napa Earthquake (United States)

    Rosinski, A.; Parrish, J.; Mccrink, T. P.; Tremayne, H.; Ortiz, M.; Greene, M.; Berger, J.; Blair, J. L.; Johnson, M.; Miller, K.; Seigel, J.; Long, K.; Turner, F.


    The Clearinghouse's principal functions are to 1) coordinate field investigations of earth scientists, engineers, and other participating researchers; 2) facilitate sharing of observations through regular meetings and through the Clearinghouse website; and 3) notify disaster responders of crucial observations or results. Shortly after 3:20 a.m., on August 24, 2014, Clearinghouse management committee organizations, the California Geological Survey (CGS), the Earthquake Engineering Research Institute (EERI), the United States Geological Survey (USGS), the California Office of Emergency Services (CalOES), and the California Seismic Safety Commission (CSSC), authorized activation of a virtual Clearinghouse and a physical Clearinghouse location. The California Geological Survey, which serves as the permanent, lead coordination organization for the Clearinghouse, provided all coordination with the state for all resources required for Clearinghouse activation. The Clearinghouse physical location, including mobile satellite communications truck, was opened at a Caltrans maintenance facility located at 3161 Jefferson Street, in Napa. This location remained active through August 26, 2014, during which time it drew the participation of over 100 experts from more than 40 different organizations, and over 1730 remote visitors via the Virtual Clearinghouse and online data compilation map. The Clearinghouse conducted three briefing calls each day with the State Operations Center (SOC) and Clearinghouse partners, and also conducted nightly briefings, accessible to remote participants via webex, with field personnel. Data collected by field researchers was compiled into a map through the efforts of EERI and USGS volunteers in the Napa Clearinghouse. EERI personnel continued to provide updates to the compilation map over an extended period of time following de-activation of the Clearinghouse. In addition, EERI managed the Clearinghouse website. Two overflights were conducted, for

  16. Dynamically Triggered Earthquakes in the Geysers Region following the 2014 M6.0 South Napa Earthquake (United States)

    Meng, X.; Peng, Z.; Aiken, C.; Kilb, D.


    The 08/24/2014 M6.0 South Napa earthquake is the largest seismic event to strike the San Francisco Bay Area since the 10/17/1989 M6.9 Loma Prieta earthquake. The South Napa event caused severe damage near the epicenter. Based on the Northern California Seismic Network (NCSN) catalog, we find a clear increase of seismicity near the Geysers Geothermal Field following the South Napa event, which is located along its rupture directivity path ~50 km NNW from the hypocenter. Visually inspecting 10 Hz high-pass filtered waveforms at seismic stations near Geysers, we can identify many local earthquakes during the surface waves of the mainshock event that are missing from the NCSN catalog. To obtain a more complete catalog, we apply a recently developed matched filter technique to detect new events within continuous seismic recordings from 74 seismic stations near the Geysers. We use 4000 local earthquakes listed in the NCSN catalog from 06/01/2014 to 09/10/2014 as templates and systematically scan continuous data within ±7 days from the South Napa mainshock. As a result, we detect ~10 times more earthquakes than in the NCSN catalog, and the magnitude of completeness reduces from 0.75 to -0.6. Of the 8091 new events, 28 occurred within the mainshock wavetrain. Depending on the filter used, the first triggered event has an inferred magnitude in the range 3.6-4.0. The intensive seismic activity near the Geysers gradually decays with a p-value of ~0.7 and returns to pre-shock level in about one day. We fit the seismicity rate in the week prior to the South Napa event with the Epidemic Type Aftershock Sequence (ETAS) model and extrapolate to obtain a post-mainshock rate. The observed post-mainshock seismicity rate clearly deviates from the ETAS prediction, which suggests that not all increased seismicity near the Geysers can be explained as aftershocks of the first triggered event. Instead these new events may be associated with stress transients (e.g. creep) or fluid

  17. Calculation of the Rate of M>6.5 Earthquakes for California and Adjacent Portions of Nevada and Mexico (United States)

    Frankel, Arthur; Mueller, Charles


    One of the key issues in the development of an earthquake recurrence model for California and adjacent portions of Nevada and Mexico is the comparison of the predicted rates of earthquakes with the observed rates. Therefore, it is important to make an accurate determination of the observed rate of M>6.5 earthquakes in California and the adjacent region. We have developed a procedure to calculate observed earthquake rates from an earthquake catalog, accounting for magnitude uncertainty and magnitude rounding. We present a Bayesian method that corrects for the effect of the magnitude uncertainty in calculating the observed rates. Our recommended determination of the observed rate of M>6.5 in this region is 0.246 ? 0.085 (for two sigma) per year, although this rate is likely to be underestimated because of catalog incompleteness and this uncertainty estimate does not include all sources of uncertainty.

  18. Seismo-Ionospheric Precursor in the GIM TEC of the 24 August 2014 M6 Napa Earthquake (United States)

    Wu, T. Y.; Liu, T. J. Y.; Liu, J. Y.


    This study examines seismo-ionospheric precursors (SIPs) in the global ionosphere map (GIM) of the total electron content (TEC) associated with the 24 August 2014 M6 South Napa earthquake and statistical evidence of SIPs of the GPS TEC in western USA during 2000-2014. The temporal SIP in the GIM TEC around the epicenter significantly decreasing (negative anomaly) on 22 August. To discriminate the global effect, such as solar flares, magnetic storms, etc., and the local effect, such as earthquakes, 5183 lattices on the GIM are employed to conduct a global search of the SIP distribution. Anomalies of both GIM TEC and associated gradients specifically and continuously appearing over the epicenter suggest that the SIP relate to the 2014 South Napa earthquake. A simulation is further carried out to produce the SIP in GIM TEC before the earthquake. Results indicate that the eastward electric field generated over the epicenter area during the earthquake preparation period to be essential.

  19. Near-Field Deformation Associated with the M6.0 South Napa Earthquake Surface Rupture (United States)

    Brooks, B. A.; Hudnut, K. W.; Glennie, C. L.; Ericksen, T.


    We characterize near-field deformation associated with the surface rupture of the M6.0 South Napa earthquake from repeat mobile laser scanning (MLS) surveys. Starting the day after the main shock, we operated, sometime simultaneously, short (~75 m range) and medium (~400m range) range laser scanners on a truck or backpack. We scanned most of the length of the principal and secondary surface ruptures at speeds less than 10 km/hr. Scanning occurred primarily in either suburban subdivisions or cultivated vineyards of varying varietals with differing leaf patterns and stages of maturity. Spot-spacing is dense enough (100s of points/m^2) to permit creation of 10-25cm digital elevation models of much of the surface rupture. Scanned features of the right-lateral rupture include classic mole tracks through a variety of soil types, en echelon cracks, offset vine rows, and myriad types of pavement-related deformation. We estimate coseismic surface displacements ranging from 5 to 45 cm by examining offset cultural features and vine rows and by comparing the MLS data with preexisting airborne laser scans from 2003 using point-cloud and solid-modeling methodologies. Additionally, we conducted repeat MLS scans to measure the magnitude and spatial variation of fault afterslip, exceeding 20 cm in some places, particularly in the southern portion of the rupture zone. We anticipate these data sets, in conjunction with independently collected ground-based alinement arrays and space-based geodetic data will contribute significant insight into topics of current debate including assessing the most appropriate material models for shallow fault zones and how shallow and deeper fault slip relate to one another.

  20. Ground motion observations of the South Napa earthquake (M6.0 August 24, 2014) (United States)

    Baltay, A.


    The South Napa earthquake generated peak ground motions in excess of 50%g and 50 cm/s in Napa Valley and also along strike to the south, and was recorded at 17 stations within 20 km rupture distance (Rrup) of the finite fault plane, 115 stations within 50 km, and 246 within 100 km. We compare the densely recorded ground motions to existing ground motion prediction equations (GMPEs) to understand both the spatial distribution of ground-motion amplitudes and also the relative excitation and attenuation terms from the earthquake. Using the ground-motion data as reported by ShakeMap, we examine the peak ground acceleration (PGA) and velocity, as well as the pseudo-spectral acceleration (PSA) at 0.3, 1.0 and 3.0 seconds, adjusted empirically to a single site condition of 760 m/s. Overall, the ground motions on the north-south components are larger than those on the east-west, consistent with both the generally north-south strike of the fault and the rupture directivity. At the higher frequencies (PGA and PSA of 0.3 s), the close data are very consistent with the GMPEs, implying a median stress drop near 5 MPa. For the longer period data, the GMPEs underpredict the data at close stations. At all frequencies, the distance attenuation seems to be stronger than the GMPEs would predict, which could either be a station coverage bias, given that most of the stations are to the south of the epicenter, or may indicate that the attenuation structure in the Napa and delta region is stronger than the average attenuation in California, on which the GMPEs were built. The spatial plot of the ground motion residuals is positive to the north, in both Napa and Sonoma Valley, consistent with both the directivity and basin effect. More interestingly, perhaps, is that there is strong ground motion to the south, as well, in the along-strike direction, particularly for PSA at 1.0s. These strongly positive residuals align along an older, Quaternary fault structure associated with the Franklin

  1. Heterogeneous stress field in the source area of the 2003 M6.4 Northern Miyagi Prefecture, NE Japan, earthquake (United States)

    Yoshida, Keisuke; Hasegawa, Akira; Okada, Tomomi


    We investigated a detailed spatial distribution of principal stress axis orientations in the source area of the 2003 M6.4 Northern Miyagi Prefecture earthquake that occurred in the forearc of northeastern Japan. Aftershock hypocentres were precisely relocated by applying the double difference method to arrival time data obtained at temporary stations as well as at surrounding routine stations. We picked many P-wave polarity data from seismograms at these stations, which enabled us to obtain 312 well-determined focal mechanism solutions. Stress tensor inversions were performed by using these focal mechanism data. The results show that quite a lot of focal mechanisms are difficult to explain by the uniform stress field, especially near the large slip area of the main-shock rupture. Stress tensor inversions at the location of individual earthquakes show that σ1 axes are orientated mainly to WSW-ENE in the northern part of the source area, while they are oriented to NW-SE in the southern part. This spatial pattern is roughly similar to those of the static stress change by the main shock, which suggests that the observed spatially heterogeneous stress field was formed by the static stress change. If this is the case, the deviatoric stress magnitude before the main shock was very small. Another possibility is the heterogeneous stress field observed after the main shock had existed even before the main shock, although we do not know why it was formed. Unfavourable orientation of the main shock fault with respect to this stress field suggests that the fault is not strong in this case too.

  2. GPS station short-term dynamic characteristics of micro displacement before Menyuan M6.4 earthquake

    Directory of Open Access Journals (Sweden)

    Wei Feng


    Full Text Available Continuous observation data from 24 GPS stations are selected in the area (33.0°N–41.0°N, 95.0°E–105.0°E for this study (the period is from Jan. 1, 2015 to Jan. 20, 2016. Three components, NS, EW and UD, of the daily solutions are filtered by the Hilbert–Huang transform (HHT with frequency band of 5.787 × 10−7–7.716 × 10−8 Hz (20–150 days in period. And short-term dynamic characteristics of micro displacement before Menyuan M6.4 earthquake are studied by using the temporal dependencies and cross spectrum analysis. The results show that before the earthquake the horizontal undulatory motions are higher than the average level in the series data which indicate the disturbance feature of regional stress before the earthquake. Three GPS stations on Qinghai-Tibet Plateau with their setting perpendicular to the seismogenic fault have consistent movement. The increase of amplitude of the horizontal micro motion observed before the quake is conducive to the earthquake occurrence. However, we could not be sure if the undulatory motion triggered the earthquake. It is quite necessary to build more GPS continuous observation stations and optimize the monitoring network so as to improve the understanding of the short-term dynamic crustal variation before earthquake.

  3. Geodetic constraints on the 2014 M 6.0 South Napa earthquake (United States)

    Barnhart, William D.; Murray, Jessica R.; Yun, S H; Svarc, Jerry L.; Samsonov, SV; Fielding, EJ; Brooks, Benjamin A.; Milillo, Pietro


    On 24 August 2014, the M 6.0 South Napa earthquake shook much of the San Francisco Bay area, leading to significant damage in the Napa Valley. The earthquake occurred in the vicinity of the West Napa fault (122.313° W, 38.22° N, 11.3 km), a mapped structure located between the Rodger’s Creek and Green Valley faults, with nearly pure right‐lateral strike‐slip motion (strike 157°, dip 77°, rake –169°;, last accessed December 2014) (Fig. 1). The West Napa fault previously experienced an M 5 strike‐slip event in 2000 but otherwise exhibited no previous definitive evidence of historic earthquake rupture (Rodgers et al., 2008; Wesling and Hanson, 2008). Evans et al. (2012) found slip rates of ∼9.5  mm/yr along the West Napa fault, with most slip rate models for the Bay area placing higher slip rates and greater earthquake potential on the Rodger’s Creek and Green Valley faults, respectively (e.g., Savage et al., 1999; d’Alessio et al., 2005; Funning et al., 2007).

  4. SELF and VLF electromagnetic emissions that preceded the M6.2 Central Italy earthquake occurred on August 24, 2016 (United States)

    Cataldi, Daniele; Cataldi, Gabriele; Straser, Valentino


    On August 24, 2016 at 01:36:32 UTC a destructive earthquake hit Central Italy with a magnitude of M6.2. The authors of this study have recorded some electromagnetic signals that have preceded this strong earthquake. These signals were recorded through two electromagnetic monitoring stations realized by Gabriele Cataldi and Daniele Cataldi, located near the town of Albano Laziale (Rome, Italy) and near the city of Lariano (Rome, Italy) and can monitor the radio spectrum 24h7 between 0.001 Hz and 96 kHz (SELF-LF band). The electromagnetic monitoring allowed to identify two interesting types of electromagnetic anomalies: the first electromagnetic anomaly was recorded on August 18, 2016 between 02:47 UTC and 06:21 UTC, in the VLF band prevalently between 18kHz and 26kHz; the second electromagnetic anomaly was registered between 08:00 UTC on August 23, 2016 and 05:00 UTC on August 24, 2016, prevalently between 0.01 and 0.7Hz: the most intense signals were recorded at 08:50 UTC on August 23, 2016 and approximately 1 hour before the strong earthquake. The Earth's electromagnetic background monitoring in the SELF-VLF band (0Hztechnological) have allowed us to understand that there are actually two families of pre-seismic radio emissions: 1) radio emissions identified as Earth's geomagnetic field disturbances related to "near Earth" solar wind proton density increase variations, and for this reason it can be seen from any point on the Earth (this is "no local" type emissions); 2) radio signals are not connected directly to the solar and geomagnetic activity: these radio signals are probably generated by piezoelectricity phenomena occurring near the focal area of the earthquake and are detectable near earthquake epicenter (this is a "local" type emissions). It is therefore clear that the monitoring of solar activity and Earth's geomagnetic activity is an activity of fundamental importance to be able to have a general understanding of pre-seismic radio signals nature. In fact

  5. Validation of a ground motion synthesis and prediction methodology for the 1988, M=6.0, Saguenay Earthquake

    Energy Technology Data Exchange (ETDEWEB)

    Hutchings, L.; Jarpe, S.; Kasameyer, P.; Foxall, W.


    We model the 1988, M=6.0, Saguenay earthquake. We utilize an approach that has been developed to predict strong ground motion. this approach involves developing a set of rupture scenarios based upon bounds on rupture parameters. rupture parameters include rupture geometry, hypocenter, rupture roughness, rupture velocity, healing velocity (rise times), slip distribution, asperity size and location, and slip vector. Scenario here refers to specific values of these parameters for an hypothesized earthquake. Synthetic strong ground motion are then generated for each rupture scenario. A sufficient number of scenarios are run to span the variability in strong ground motion due to the source uncertainties. By having a suite of rupture scenarios of hazardous earthquakes for a fixed magnitude and identifying the hazard to the site from the one standard deviation value of engineering parameters we have introduced a probabilistic component to the deterministic hazard calculation, For this study we developed bounds on rupture scenarios from previous research on this earthquake. The time history closest to the observed ground motion was selected as a model for the Saguenay earthquake.

  6. Soil radon and electromagnetic anomalies before the Ileia(Greece) M6.8 earthquake (United States)

    Nikolopoulos, D.; Vogiannis, E.; Louizi, A.; Zisos, A.


    Radon (222Rn) is a radioactive gas generated by the decay of the naturally occurring 238U series. It is considered very important from radiological point of view, since it accounts for more than half of the natural exposure of the general public. Radon has been used as trace gas in several studies of Earth, hydrogeology and atmosphere, due to its 3.82-day half-life (which allows migration at long distances) and its alpha decay (which enables low level of detection). It has been accounted in the search of earthquake precursors, volcanic processes, fluid circulation in karstic sources and in the study of natural ventilation of underground cavities. Radon anomalies impending great earthquakes have been observed in groundwater, thermal waters soil gas and in underground tunnels. Ileia is a very active tectonic site located in SW Greece, dominated by extensional active seismicity structures (e.g. Alfeios, Neda, Melpeia, Kiparissia-Aetos). Its instrumental and felt seismicity is very high, with more than 600 earthquakes of magnitude greater than 4.0 R in the last 100 years two of which occurred during the last 15 years and were very destructive (5.8 R on 26/3/93 and 6.8 R on 8/6/08 respectively). Hence, it is an area benefiting from the installation of a geophysical monitoring station, where radon exhalation associated with the accumulation or release of tectonic strain can be studied. In the aforementioned consensus, a station for the surveillance of soil radon has been installed in Kardamas Ileias, 3 km south from Amaliada which is the second highly populated city. The station consists of a high precision (calibration certified) active instrument (Alpha Guard-AG, Genitron Ltd.), equipped with an appropriate unit designed for pumping and measurement of radon in soil gas (Soil gas Unit, Genitron Ltd.). Soil radon is driven into AG via a 1-m probe (to minimize meteorological influences) and a 25-m radon proof 25-mm tube (to avoid simultaneous measurement of soil 220Rn

  7. Surface Fault Rupture from the M6.0 South Napa Earthquake of Aug. 24, 2014 (United States)

    Ponti, D. J.; Dawson, T. E.; Schwartz, D. P.; Brooks, B. A.; DeLong, S. B.; Hecker, S.; Hudnut, K. W.; Kelson, K. I.; Lienkaemper, J. J.; Prentice, C. S.; Rosa, C. M.; Rubin, R. S.; Seitz, G. G.; Sickler, R. R.; Wesling, J. R.


    The South Napa earthquake produced the largest and most extensive coseismic surface rupture of any documented California earthquake of similar magnitude. More than 14 km of complex surface faulting, extending from the Napa River at Cuttings Wharf northward beyond the north boundary of Alston Park in the city of Napa, occurred on two principal sub-parallel N-NW trending fault strands. Other minor sub-parallel rupture zones (≤1.5 km in length with ~1-3 cm displacements) were identified near the principal strands. The surface rupture lies primarily NW of the epicenter and W of most of the mapped traces of the West Napa fault zone, but rupture was locally coincident with portions of some mapped late Quaternary and older fault traces. Geomorphic expressions of prior faulting are observed intermittently along the main traces. Surface displacements are predominantly right lateral and typically expressed as discontinuous en echelonleft-stepping fractures within zones that range from pipelines, and residential structures produced significant damage. The ~7 km-long eastern strand had coseismic dextral offsets of 2-8 cm. Its southern end lies 7.5 km NW of the epicenter and 1.1 km E of the western strand, while its northern end approaches the western strand where the two appear to merge a few hundred meters south of Alston Park. Afterslip has been documented along the western strand but was not observed on the eastern strand. It was most rapid in the middle third of the western strand, increasing initial slip by ≥20 cm one day after the mainshock. Repeated measurements suggest total slip may reach ~40 cm along half of the western strand. The complex character and locations of surface rupture produced by this event have significant implications for current approaches to fault hazard mapping in California. Additional contributors: USGS: N. Avdievitch, M. Bennett, B. Collins, T. Holzer, A. Pickering, J. Tinsley. CGS: D. Branum, B. Bryant, C. Davenport, M. Delattre, W

  8. Offline Performance of the Filter Bank EEW Algorithm in the 2014 M6.0 South Napa Earthquake (United States)

    Meier, M. A.; Heaton, T. H.; Clinton, J. F.


    Medium size events like the M6.0 South Napa earthquake are very challenging for EEW: the damage such events produce can be severe, but it is generally confined to relatively small zones around the epicenter and the shaking duration is short. This leaves a very short window for timely EEW alerts. Algorithms that wait for several stations to trigger before sending out EEW alerts are typically not fast enough for these kind of events because their blind zone (the zone where strong ground motions start before the warnings arrive) typically covers all or most of the area that experiences strong ground motions. At the same time, single station algorithms are often too unreliable to provide useful alerts. The filter bank EEW algorithm is a new algorithm that is designed to provide maximally accurate and precise earthquake parameter estimates with minimum data input, with the goal of producing reliable EEW alerts when only a very small number of stations have been reached by the p-wave. It combines the strengths of single station and network based algorithms in that it starts parameter estimates as soon as 0.5 seconds of data are available from the first station, but then perpetually incorporates additional data from the same or from any number of other stations. The algorithm analyzes the time dependent frequency content of real time waveforms with a filter bank. It then uses an extensive training data set to find earthquake records from the past that have had similar frequency content at a given time since the p-wave onset. The source parameters of the most similar events are used to parameterize a likelihood function for the source parameters of the ongoing event, which can then be maximized to find the most likely parameter estimates. Our preliminary results show that the filter bank EEW algorithm correctly estimated the magnitude of the South Napa earthquake to be ~M6 with only 1 second worth of data at the nearest station to the epicenter. This estimate is then

  9. Brief Communication: An exclusive example of surface latent heat flux variation before Russia M6.1 earthquake

    Directory of Open Access Journals (Sweden)

    Y. Jie


    Full Text Available Recently surface latent heat flux (SLHF data is widely used to study the anomalies before earthquakes. Most researches use the daily SLHF data, here we use both daily data and high temporal resolution (four times one day SLHF data, and compare the SLHF change with satellite image at the first time. We check the data from 1 September to 30 October 2011 and the result shows that there is really a very high SLHF anomaly (bigger than 2 σ just 5 days before the M6.1 Russia earthquake which occurred on 14 October 2011. It should be considered as a preseismic precursor if judged with previously published methods. But our comparison between SLHF change and satellite image shows that the SLHF anomaly is just caused by a thick cloud. This result tells us that scientists must know the data's meaning before they use it, if not, they may get a wrong conclusion. Based on this example, we suggest that previously published SLHF anomaly before earthquake should be reanalyzed by our method to exclude the false anomaly.

  10. Seismic Documentation for Rock Damage and Heal on the San Andreas Fault Involved in the 2004 M6 Parkfield Earthquake (United States)

    Malin, P. M.; Li, Y.; Chen, P.; Cochran, E. M.; Vidale, J. E.


    After the M6 Parkfield earthquake that occurred on 28 September 2004, we deployed a dense seismic array at the same sites as used in our experiment in the fall of 2002. The measurements using moving-window cross- correlation of waveforms for the repeated explosions and microearthquakes recorded in 2002 and 2004 show a decrease in shear velocity of at least ~2.5% within a ~200-m-wide zone across the San Andreas main fault trace most likely owing to co-seismic damage of fault rocks caused by dynamic rupture in this M6 earthquake. The width of the damage zone characterized by larger velocity changes is consistent with the low-velocity waveguide model on the SAF near Parkfield derived from fault-zone trapped waves [Li et al., 2004]. The estimated ratio between the P and S wave traveltime changes is 0.57 within the rupture zone and ~0.65 in the surrounding rocks, indicating wetter cracks within the damaged fault zone, probably due to the ground water percolating into the cracks opened in the mainshock. The measurements of traveltime changes for repeated aftershocks in 21 clusters, with a total of ~130 events, located at different depths along the rupture in 2004 show that the maximum shear velocity increased by ~1.2% within the damage zone in 3.5 months starting a week after the mainshock, indicating that the fault heals in the post-seismic stage due to the closure of cracks in the damaged rock. The data recorded at a seismograph installed in the SAFOD mainhole passing the San Andreas fault zone at ~3-km depths for repeated aftershocks in December of 2004 and later show that seismic velocities within the damage zone were changed by ~0.3% in a month, but no changes were registered at seismographs installed in the vertical pilot borehole drilled ~1.8 km away from the main fault trace for the same repeated events. We find that the healing rate is logarithmically decreasing through time with greater healing rate in the earlier stage after the mainshock. The magnitude of

  11. Investigation of the M6.6 Niigata-Chuetsu Oki, Japan, earthquake of July 16, 2007 (United States)

    Kayen, Robert; Collins, Brian D.; Abrahamson, Norm; Ashford, Scott; Brandenberg, Scott J.; Cluff, Lloyd; Dickenson, Stephen; Johnson, Laurie; Tanaka, Yasuo; Tokimatsu, Kohji; Kabeyasawa, Toshimi; Kawamata, Yohsuke; Koumoto, Hidetaka; Marubashi, Nanako; Pujol, Santiago; Steele, Clint; Sun, Joseph I.; Tsai, Ben; Yanev, Peter; Yashinsky, Mark; Yousok, Kim


    The M6.6 mainshock of the Niigata Chuetsu Oki (offshore) earthquake occurred at 10:13 a.m. local time on July 16, 2007, and was followed by a sequence of aftershocks that were felt during the entire time of the reconnaissance effort. The mainshock had an estimated focal depth of 10 km and struck in the Japan Sea offshore Kariwa. Analysis of waveforms from source inversion studies indicates that the event occurred along a thrust fault with a NE trend. The fault plane is either a strike of 34 degrees with a dip of 51 degrees or a strike of 238 degrees with a dip of 41 degrees. Which of these two planes is associated with the mainshock rupture is unresolved, although attenuation relationship analysis indicates that the northwest-dipping fault is favored. The quake affected an approximately 100-km-wide area along the coastal areas of southwestern Niigata prefecture. The event triggered ground failures as far as the Unouma Hills, located in central Niigata approximately 50 km from the shore and the source area of the 2004 Niigata Chuetsu earthquake. The primary event produced tsunami run-ups that reached maximum runup heights of about 20 centimeters along the shoreline of southern Niigata Prrefecture.

  12. Seismic evidence for rock damage and healing on the San Andreas fault associated with the 2004 M 6.0 Parkfield earthquake (United States)

    Li, Y.-G.; Chen, P.; Cochran, E.S.; Vidale, J.E.; Burdette, T.


    We deployed a dense linear array of 45 seismometers across and along the San Andreas fault near Parkfield a week after the M 6.0 Parkfield earthquake on 28 September 2004 to record fault-zone seismic waves generated by aftershocks and explosions. Seismic stations and explosions were co-sited with our previous experiment conducted in 2002. The data from repeated shots detonated in the fall of 2002 and 3 months after the 2004 M 6.0 mainshock show ???1.0%-1.5% decreases in seismic-wave velocity within an ???200-m-wide zone along the fault strike and smaller changes (0.2%-0.5%) beyond this zone, most likely due to the coseismic damage of rocks during dynamic rupture in the 2004 M 6.0 earthquake. The width of the damage zone characterized by larger velocity changes is consistent with the low-velocity waveguide model on the San Andreas fault, near Parkfield, that we derived from fault-zone trapped waves (Li et al., 2004). The damage zone is not symmetric but extends farther on the southwest side of the main fault trace. Waveform cross-correlations for repeated aftershocks in 21 clusters, with a total of ???130 events, located at different depths and distances from the array site show ???0.7%-1.1% increases in S-wave velocity within the fault zone in 3 months starting a week after the earthquake. The velocity recovery indicates that the damaged rock has been healing and regaining the strength through rigidity recovery with time, most likely . due to the closure of cracks opened during the mainshock. We estimate that the net decrease in seismic velocities within the fault zone was at least ???2.5%, caused by the 2004 M 6.0 Parkfield earthquake. The healing rate was largest in the earlier stage of the postmainshock healing process. The magnitude of fault healing varies along the rupture zone, being slightly larger for the healing beneath Middle Mountain, correlating well with an area of large mapped slip. The fault healing is most prominent at depths above ???7 km.

  13. Solar wind triggering of geomagnetic disturbances and strong (M>6.8) earthquakes during the November - December 2004 period

    CERN Document Server

    Anagnostopoulos, G; Antoniou, P


    This paper brings space weather prediction close to earthquake (EQ) prediction research. The results of this paper support conclusions of previously presented statistical studies that solar activity influences the seismic activity, this influence is mediated through rapid geomagnetic disturbances and the geomagnetic disturbances are related with increases of solar wind speed. Our study concern an example of 40 days with direct response of a series of 7 strong-to-giant (M=6.8-9.3) EQs (including the Andaman-Sumatra EQ) to solar wind speed increases and subsequent geomagnetic fast disturbances. Our analysis for 10 M>6 EQs from November 23 to December 28, 2004 suggests a mean time response delay of EQs to fast geomagnetic disturbances of ~1.5 days. The two giant EQs during this period occurred after the two fastest geomagnetic variations, as revealed by the ratio of the daily Kp index variation over a day {\\Delta}Kp/{\\Delta}t (12 and 15, respectively). It suggests that the fast disturbance of the magnetosphere, ...

  14. Seismicity rate changes along the central California coast due to stress changes from the 2003 M 6.5 San Simeon and 2004 M 6.0 Parkfield earthquakes (United States)

    Aron, A.; Hardebeck, J.L.


    We investigated the relationship between seismicity rate changes and modeled Coulomb static stress changes from the 2003 M 6.5 San Simeon and the 2004 M 6.0 Parkfield earthquakes in central California. Coulomb stress modeling indicates that the San Simeon mainshock loaded parts of the Rinconada, Hosgri, and San Andreas strike-slip faults, along with the reverse faults of the southern Los Osos domain. All of these loaded faults, except for the San Andreas, experienced a seismicity rate increase at the time of the San Simeon mainshock. The Parkfield earthquake occurred 9 months later on the loaded portion of the San Andreas fault. The Parkfield earthquake unloaded the Hosgri fault and the reverse faults of the southern Los Osos domain, which both experienced seismicity rate decreases at the time of the Parkfield event, although the decreases may be related to the decay of San Simeon-triggered seismicity. Coulomb stress unloading from the Parkfield earthquake appears to have altered the aftershock decay rate of the southern cluster of San Simeon after-shocks, which is deficient compared to the expected number of aftershocks from the Omori decay parameters based on the pre-Parkfield aftershocks. Dynamic stress changes cannot explain the deficiency of aftershocks, providing evidence that static stress changes affect earthquake occurrence. However, a burst of seismicity following the Parkfield earthquake at Ragged Point, where the static stress was decreased, provides evidence for dynamic stress triggering. It therefore appears that both Coulomb static stress changes and dynamic stress changes affect the seismicity rate.

  15. Source parameters of the M 6.5 Skyros Island (North Aegean Sea earthquake of July 26, 2001

    Directory of Open Access Journals (Sweden)

    A. Kiratzi


    Full Text Available Teleseismic body wave modelling, time domain moment tensor inversion of regional waveforms and spectral analysis of the far-field P-wave pulses are used to derive the source parameters of the July 26, 2001 Skyros earthquake (M 6.5. Its epicentre is located south of the Sporades Islands in the North Aegean Sea (Greece. Previous focal mechanism solutions indicate motion on strike-slip faults. The time domain moment tensor inversion is applied for the first time to the regional waveforms of the recently established broadband network in Greece. Its application gave results which are highly consistent with teleseismic waveform modelling. The results of this study, in combination with the distribution of aftershocks, indicate left-lateral strike slip motion on a NW-SE striking fault with parameters: fault plane (strike = 151°, dip = 83°, rake = 7° and auxiliary plane (strike = 60°, dip = 84°, rake = 173°, depth 12 km and M 0 = 5.98e18 N m. Moreover, the time domain moment tensor inversion technique yielded a pure double couple source with negligible CLVD. The spectral analysis of the far-field P-wave pulses resulted in a fault length L ~ 32 km, stress drop ~ 9 bars and average displacement u ~ 30 cm.These values are in very good agreement with those estimated from empirical scaling relations applicable to the Aegean area.

  16. Preliminary simulation of a M6.5 earthquake on the Seattle Fault using 3D finite-difference modeling (United States)

    Stephenson, William J.; Frankel, Arthur D.


    A three-dimensional finite-difference simulation of a moderate-sized (M 6.5) thrust-faulting earthquake on the Seattle fault demonstrates the effects of the Seattle Basin on strong ground motion in the Puget lowland. The model area includes the cities of Seattle, Bremerton and Bellevue. We use a recently developed detailed 3D-velocity model of the Seattle Basin in these simulations. The model extended to 20-km depth and assumed rupture on a finite fault with random slip distribution. Preliminary results from simulations of frequencies 0.5 Hz and lower suggest amplification can occur at the surface of the Seattle Basin by the trapping of energy in the Quaternary sediments. Surface waves generated within the basin appear to contribute to amplification throughout the modeled region. Several factors apparently contribute to large ground motions in downtown Seattle: (1) radiation pattern and directivity from the rupture; (2) amplification and energy trapping within the Quaternary sediments; and (3) basin geometry and variation in depth of both Quaternary and Tertiary sediments

  17. Rapid Response Products of The ARIA Project for the M6.0 August 24, 2014 South Napa Earthquake (United States)

    Yun, S. H.; Owen, S. E.; Hua, H.; Milillo, P.; Fielding, E. J.; Hudnut, K. W.; Dawson, T. E.; Mccrink, T. P.; Jo, M. J.; Barnhart, W. D.; Manipon, G. J. M.; Agram, P. S.; Moore, A. W.; Jung, H. S.; Webb, F.; Milillo, G.; Rosinski, A.


    A magnitude 6.0 earthquake struck southern Napa county northeast of San Francisco, California, on Aug. 24, 2014, causing significant damage in the city of Napa and nearby areas. One day after the earthquake, the Advanced Rapid Imaging and Analysis (ARIA) team produced and released observations of coseismic ground displacement measured with continuous GPS stations of the Plate Boundary Observatory (operated by UNAVCO for the National Science Foundation) and the Bay Area Rapid Deformation network (operated by Berkeley Seismological Laboratory). Three days after the earthquake (Aug. 27), the Italian Space Agency's (ASI) COSMO-SkyMed (CSK) satellite acquired their first post-event data. On the same day, the ARIA team, in collaboration with ASI and University of Basilicata, produced and released a coseismic interferogram that revealed ground deformation and surface rupture. The depiction of the surface rupture - discontinuities of color fringes in the CSK interferogram - helped guide field geologists from the US Geological Survey and the California Geological Survey (CGS) to features that may have otherwise gone undetected. Small-scale cracks were found on a runway of the Napa County Airport, as well as bridge damage and damaged roads. ARIA's response to this event highlighted the importance of timeliness for mapping surface deformation features. ARIA's rapid response products were shared through Southern California Earthquake Center's response website and the California Earthquake Clearinghouse. A damage proxy map derived from InSAR coherence of CSK data was produced and distributed on Aug. 27. Field crews from the CGS identified true and false positives, including mobile home damage, newly planted grape vines, and a cripple wall failure of a house. Finite fault slip models constrained from CSK interferograms and continuous GPS observations reveal a north-propagating rupture with well-resolved slip from 0-10.5 km depth. We also measured along-track coseismic

  18. Coseismic deformation, field observations and seismic fault of the 17 November 2015 M = 6.5, Lefkada Island, Greece earthquake (United States)

    Ganas, Athanassios; Elias, Panagiotis; Bozionelos, George; Papathanassiou, George; Avallone, Antonio; Papastergios, Asterios; Valkaniotis, Sotirios; Parcharidis, Issaak; Briole, Pierre


    On November 17, 2015 07:10:07 UTC a strong, shallow Mw6.5 earthquake, occurred on the island of Lefkada along a strike-slip fault with right-lateral sense of slip. The event triggered widespread environmental effects at the south and western part of the island while, the intensity and severity of these earthquake-induced deformations is substantially decreased towards the eastern part of the island. Relocation of seismicity and inversion of geophysical (GPS, InSAR) data indicate that the seismic fault runs parallel to the west coast of Lefkada, along the Aegean - Apulia plate boundary. The fault plane strikes N20 ± 5°E and dips to east with an angle of about 70 ± 5°. Coseismic deformation was measured in the order of tens of centimeters of horizontal motion by continuous GPS stations of NOANET (the NOA GPS network) and by InSAR (Sentinel 1 A image pairs). A coseismic uniform-slip model was produced from inversion of InSAR data and permanent GPS stations. The earthquake measured Mw = 6.5 using both the geodetic moment produced by the slip model, as well as the PGD relation of Melgar et al. (2015, GRL). In the field we observed no significant vertical motion of the shoreline or surface expression of faulting, this is consistent with the predictions of the model. The interferograms show a large decorrelation area that extends almost along all the western coast of Lefkada. This area correlates well with the mapped landslides. The 2003-2015 pattern of seismicity in the Ionian Sea region indicates the existence of a 15-km seismic gap offshore NW Cephalonia.

  19. Building Damage Assessment Using Multisensor Dual-Polarized Synthetic Aperture Radar Data for the 2016 M 6.2 Amatrice Earthquake, Italy

    Directory of Open Access Journals (Sweden)

    Sadra Karimzadeh


    Full Text Available On 24 August 2016, the M 6.2 Amatrice earthquake struck central Italy, well-known as a seismically active region, causing considerable damage to buildings in the town of Amatrice and the surrounding area. Damage from this earthquake was assessed quantitatively by means of multitemporal synthetic aperture radar (SAR coherence and SAR intensity methods using dual-polarized SAR data obtained from the Sentinel-1 (VV, VH and ALOS-2 (HH, HV satellites. We developed linear discriminant functions based on three items: (1 the differential coherence values; (2 the differential backscattering intensity values of pre- and post-event images; and (3 a binary damage map of the optical pre- and post-event imagery. The accuracy of the proposed model was 84% for the Sentinel-1 data and 76% for the ALOS-2 data. The damage proxy maps deduced from the linear discriminant functions can be useful in the parcel-by-parcel assessment of building damage and development of spatial models for the allocation of urban search and rescue operations.

  20. Numerical Shake Prediction for Earthquake Early Warning: More Precise and Rapid Prediction even for Deviated Distribution of Ground Shaking of M6-class Earthquakes (United States)

    Hoshiba, M.; Ogiso, M.


    In many methods of the present EEW systems, hypocenter and magnitude are determined quickly, and then the strengths of ground motions are predicted using the hypocentral distance and magnitude based on a ground motion prediction equation (GMPE), which usually leads the prediction of concentric distribution. However, actual ground shaking is not always concentric, even when site amplification is corrected. At a common site, the strengths of shaking may be much different among earthquakes even when their hypocentral distances and magnitudes are almost the same. For some cases, PGA differs more than 10 times, which leads to imprecise prediction in EEW. Recently, Numerical Shake Prediction method was proposed (Hoshiba and Aoki, 2015), in which the present ongoing wavefield of ground shaking is estimated using data assimilation technique, and then future wavefield is predicted based on physics of wave propagation. Information of hypocentral location and magnitude is not required in this method. Because future is predicted from the present condition, it is possible to address the issue of the non-concentric distribution. Once the deviated distribution is actually observed in ongoing wavefield, future distribution is predicted accordingly to be non-concentric. We will indicate examples of M6-class earthquakes occurred at central Japan, in which strengths of shaking were observed to non-concentrically distribute. We will show their predictions using Numerical Shake Prediction method. The deviated distribution may be explained by inhomogeneous distribution of attenuation. Even without attenuation structure, it is possible to address the issue of non-concentric distribution to some extent once the deviated distribution is actually observed in ongoing wavefield. If attenuation structure is introduced, we can predict it before actual observation. The information of attenuation structure leads to more precise and rapid prediction in Numerical Shake Prediction method for EEW.

  1. Application of scaling-rule theory in crustal rock fracture to studying characteristics of seismological precursors associated with M=6.1 Shandan-Minle earthquake

    Institute of Scientific and Technical Information of China (English)

    RONG Dai-lu; LI Ya-rong; HAN Xiao-ming


    In the paper, we introduce Allegre's scaling-rule theory of rock fracture and the probability to develop a method for predicting earthquake occurrence time on its basis. As an example, we study the characteristics of seismological precursors (seismic spatial correlation length and coda Qc) associated with the earthquake (M=6.1) occurred in Shandan-Minle, Gansu Province. The results show an increasing trend of seismic spatial correlation length and coda Qc before the earthquake. And a power exponent relation is used to fit the increasing variation form of these two parameters. The study has provided a basis for creating a method and finding indexes to predict the earthquake occurrence time by using the monitored seismic spatial correlation length and coda Qc.

  2. Predicted liquefaction in the greater Oakland area and northern Santa Clara Valley during a repeat of the 1868 Hayward Fault (M6.7-7.0) earthquake (United States)

    Holzer, Thomas L.; Noce, Thomas E.; Bennett, Michael J.


    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 young Holocene levee deposits along major drainages where liquefaction and lateral spreading occurred during large earthquakes in 1868 and 1906.

  3. On the recent M=6.1 earthquake occurred at Kefalonia island (South-West Greece) on 26 January 2014: Manifestations of an Earth system in critical state

    CERN Document Server

    Contoyiannis, Y; Kopanas, J; Antonopoulos, G; Koulouras, G; Eftaxias, K; Nomicos, C


    In this paper we show, in terms of fracture-induced electromagnetic emissions (EME) recorded two days prior to the earthquake of Kefalonia (Cephalonia), Greece [(38.22o N, 20.53oE), 26 January 2014, M=6.1] that the Earth system around the focal area came to critical condition two days before the earthquake occurence. Specifically, the MHz EME recorded by the remote telemetric stations on the island of Kefalonia and the neighboring island of Zante came simultaneously to critical conditions. The analysis was performed by means of the method of critical fluctuations (MCF) revealing critical features.

  4. Afterslip behavior following the M6.0, 2014 South Napa earthquake with implications for afterslip forecasting on other seismogenic faults (United States)

    Lienkaemper, James J.; DeLong, Stephen B.; Domrose, Carolyn J; Rosa, Carla M.


    The M6.0, 24 Aug. 2014 South Napa, California, earthquake exhibited unusually large slip for a California strike-slip event of its size with a maximum coseismic surface slip of 40-50 cm in the north section of the 15 km-long rupture. Although only minor (Napa afterslip suggests how we might approach the scientific and engineering challenges of afterslip from a much larger M~7 earthquake anticipated on the nearby, urban Hayward Fault. However, we expect its afterslip to last much longer than one year.The M6.0, 24 Aug. 2014 South Napa, California, earthquake exhibited unusually large slip for a California strike-slip event of its size with a maximum coseismic surface slip of 40-50 cm in the north section of the 15 km-long rupture. Although only minor (Napa afterslip suggests how we might approach the scientific and engineering challenges of afterslip from a much larger M~7 earthquake anticipated on the nearby, urban Hayward Fault. However, we expect its afterslip to last much longer than one year.

  5. Total electron content variations over southern Europe before and during the M 6.3 Abruzzo earthquake of April 6, 2009

    Directory of Open Access Journals (Sweden)

    Spyrous D. Spatalas


    Full Text Available

    Total electron content (TEC data of 14 global positioning system (GPS stations of the EUREF network were provided by the IONOLAB. These were analyzed using wavelet analysis and discrete Fourier analysis to investigate the TEC variations over southern Europe in the month before the catastrophic Abruzzo earthquake of M 6.3 of April 6, 2009. The main conclusions of this analysis are: (a TEC oscillations in a broad range of frequencies occurred randomly over a broad area of several hundred kilometers from the earthquake; (b Morning and evening extensions of the day-time TEC values were seen for all of the EUREF stations of this program shortly before, during and shortly after the main earthquake period; (c High frequency oscillations (f $ 0.0003 Hz, period T $ 60 m appear to indicate the location of the earthquake, although with questionable accuracy, while the fractal characteristics of the frequency distribution indicates the locus of the earthquake with relatively greater accuracy. We conclude that the lithosphere-atmosphere-ionosphere coupling mechanism through acoustic or gravity waves might explain this phenomenology.

  6. Rupture complexity of the M6.0 Amatrice Earthquake probed by 1D and 3D velocity models (United States)

    Tinti, E.; Scognamiglio, L.; Casarotti, E.; Magnoni, F.; Quintiliani, M.; Michelini, A.; Cocco, M.


    On 24th August 2016 a ML 6.0 earthquake occurred in the Central Apennines (Italy) between Amatrice and Norcia causing heavy damages and nearly 300 fatalities. The main shock and most of the aftershocks show NNW-SSE striking focal mechanisms in agreement with the current NE-SW extensional tectonic setting of Central Apennines. To image the rupture history of the Amatrice earthquake, we invert the ground velocity time histories obtained from 26 three components strong motion accelerometers located within 45 km from the fault, filtered between 0.02 and 0.5 Hz. The inferred slip distribution is heterogeneous and characterized by two shallow slip patches located up-dip and NW from the hypocenter. The rupture history shows a bilateral propagation and a relatively high rupture velocity (3.1 km/s), producing evident directivity effects both N-NW and SE of the hypocenter and characterizing the recorded near-source peak ground motions. The retrieved rupture model provides a good fit to observed ground velocities up to 1 Hz, corroborating the contribution of rupture directivity and slip heterogeneity to ground shaking and damage pattern. We highlight that fault dimensions and peak slip values are relatively large for a moderate-magnitude earthquake. Finally, we have performed a forward modeling of seismic wave propagation in a 3D crustal model, using the imaged rupture history as the source model, to verify the effects of topography and velocity model on the calculated ground motions, and interpret the inferred source heterogeneity.

  7. Google earth mapping of damage from the Nigata-Ken-Chuetsu M6.6 earthquake of 16 July 2007 (United States)

    Kayen, Robert E.; Steele, WM. Clint; Collins, Brian; Walker, Kevin


    We describe the use of Google Earth during and after a large damaging earthquake thatstruck the central Japan coast on 16 July 2007 to collect and organize damage information and guide the reconnaissance activities. This software enabled greater real-time collaboration among scientists and engineers. After the field investigation, the Google Earth map is used as a final reporting product that was directly linked to the more traditional research report document. Finally, we analyze the use of the software within the context of a post-disaster reconnaissance investigation, and link it to student use of GoogleEarth in field situations

  8. Coseismic deformation and slip model of the 17 November 2015 M=6.5 earthquake, Lefkada Island, Greece (United States)

    Ganas, Athanassios; Melgar, Diego; Briole, Pierre; Geng, Jianghui; Papathanassiou, George; Bozionelos, George; Avallone, Antonio; Valkaniotis, Sotirios; Mendonidis, Evangelos; Argyrakis, Panagiotis; Moshou, Alexandra; Elias, Panagiotis


    On November 17, 2015 a strong, shallow earthquake, Mw 6.5, occurred on the island of Lefkada along a strike-slip fault with right-lateral sense of slip. The event triggered widespread environmental effects that were mainly reported at the south and western part of the island while moving towards the eastern part, the intensity and severity of these earthquake-induced deformations were decreased. Coseismic deformation was measured in the order of tens of centimeters of horizontal motion by continuous GPS stations of NOANET (the NOA GPS network) and by InSAR (Sentinel 1A image pairs). Released interferograms from various groups show a large decorrelation area that extends almost along all the western coast of Lefkada, observation which provides strong support of landsliding. We also found extensive landslides during field work and no surface ruptures. A coseismic slip model was produced from the ascending InSAR, which it's cleaner than the GPS only and both data sets have ~90% variance reduction. The fault dips to the east-southeast at an angle of 65-70 degrees.

  9. Fluid‐driven seismicity response of the Rinconada fault near Paso Robles, California, to the 2003 M 6.5 San Simeon earthquake (United States)

    Hardebeck, Jeanne L.


    The 2003 M 6.5 San Simeon, California, earthquake caused significant damage in the city of Paso Robles and a persistent cluster of aftershocks close to Paso Robles near the Rinconada fault. Given the importance of secondary aftershock triggering in sequences of large events, a concern is whether this cluster of events could trigger another damaging earthquake near Paso Robles. An epidemic‐type aftershock sequence (ETAS) model is fit to the Rinconada seismicity, and multiple realizations indicate a 0.36% probability of at least one M≥6.0 earthquake during the next 30 years. However, this probability estimate is only as good as the projection into the future of the ETAS model. There is evidence that the seismicity may be influenced by fluid pressure changes, which cannot be forecasted using ETAS. The strongest evidence for fluids is the delay between the San Simeon mainshock and a high rate of seismicity in mid to late 2004. This delay can be explained as having been caused by a pore pressure decrease due to an undrained response to the coseismic dilatation, followed by increased pore pressure during the return to equilibrium. Seismicity migration along the fault also suggests fluid involvement, although the migration is too slow to be consistent with pore pressure diffusion. All other evidence, including focal mechanisms and b‐value, is consistent with tectonic earthquakes. This suggests a model where the role of fluid pressure changes is limited to the first seven months, while the fluid pressure equilibrates. The ETAS modeling adequately fits the events after July 2004 when the pore pressure stabilizes. The ETAS models imply that while the probability of a damaging earthquake on the Rinconada fault has approximately doubled due to the San Simeon earthquake, the absolute probability remains low.

  10. A Teachable Moment in Earth Deformation: An Undergraduate Strain Module Incorporating GPS Measurement of the August 24, 2014 M6.0 South Napa Earthquake (United States)

    Resor, P. G.; Cronin, V. S.; Hammond, W. C.; Pratt-Sitaula, B.; Olds, S. E.


    The August 24, 2014 M 6.0 South Napa Earthquake was the largest earthquake to occur in the San Francisco Bay Area, home to more than 7 million people, in almost 25 years. The event occurred within an area of dense GPS instrumentation including continuous stations from the EarthScope Plate Boundary Observatory, Bay Area Regional Deformation Network and other networks. Coseismic displacements of up to 3 cm were rapidly estimated within one day after the event, providing a map of Earth shape change at over one hundred stations around the epicenter. The earthquake thus presets as an excellent "teachable moment" to introduce students to basic geoscience concepts, modern geophysical methods, and the state of knowledge in earthquake science. We have developed an example exercise that uses GPS-derived interseismic velocities and coseismic offsets to explore deformation in the vicinity of the earthquake rupture. This exercise builds on the UNAVCO education resource "Infinitesimal Strain Analysis Using GPS Data" (, a module designed to introduce undergraduate geoscience majors to concepts of crustal deformation using GPS velocity data. In the module students build their intuition about infinitesimal strain through manipulation of physical models, apply this intuition to interpret maps of GPS velocity vectors, and ultimately calculate the instantaneous deformation rate of triangles on the Earth's surface defined by three GPS sites. The South Napa data sets provide an example with clear societal relevance that can be used to explore the basic concepts of deformation, but may also be extended to explore topics such as strain accumulation, release, and transfer associated with the earthquake cycle. The UNAVCO module could be similarly extended to create additional exercises in response to future events with clear geodetic signals.

  11. Investigation of post-seismic deformation resulting from the 24th August 2016 Central Italy Earthquake (M 6.2) (United States)

    McCaffrey, K. J. W.; Gregory, L. C.; Walters, R. J.; Roberts, G.; Wilkinson, M. W.; Wedmore, L. N. J.; Michetti, A.; Vittori, E.; Livio, F.; Faure Walker, J.; Mildon, Z. K.


    Our initial satellite (InSAR) observations and field studies (Walters et al in prep) following the August 24th, 2016, Mw 6.2 Central Italy earthquake revealed that co-seismic rupture occurred on two normal fault structures, the Vettore and Laga faults, which were previously thought to be separate structures. The Laga and Vettore faults cross a major inactive thrust fault, which emplaced Lower Jurassic limestone over the Miocene flysch to the south. Our preliminary InSAR analysis indicated co-seismic slip at the surface along the Vettore fault. In the field we confirmed an c. 5 km long semi-continuous surface rupture, with remarkably consistent 15-20 cm offset downthrow to the SW on an average azimuth of 235° located along the Vettore fault bedrock scarp. The rupture becomes a series of discontinuous cracks where the fault crosses from limestone bedrock along the Vettore section into underlying flysch. A continuous surface rupture was not found elsewhere in the region, and is either not present or obscured along the Laga-Amatrice fault. We present results from our field campaign and models derived from Sentinel-1 InSAR data during the post-seismic period (images collected on average every 1.5 days) to quantify the spatial distribution and temporal evolution of the post-seismic deformation on and around the causative faults. In the field, we conducted an initial survey of two sites along the surface rupture using the Structure From Motion (SfM) photogrammetric technique, and installed 6 GNSS instruments mounted in short-baseline pairs across the Vettore fault. We will show preliminary measurements of ongoing near-field post-seismic deformation and shallow afterslip from the GNSS and time-lapse TLS (Lidar) and SfM datasets, complementing the wide-area InSAR results. Our results will provide insights into the formation of bedrock scarps from repeated earthquakes and the interpretation of Holocene slip-rate data from these scarps. The coseismic and ongoing post

  12. Plate Boundary Observatory Strainmeter Recordings of The M6.0 August 24, 2014 South Napa Earthquake (United States)

    Hodgkinson, Kathleen; Mencin, David; Phillips, David; Mattioli, Glen; Meertens, Charles


    The 2014 Mw6.0 South Napa earthquake nucleated at 11 km depth near the West Napa fault, one of a complex system of sub-parallel major right lateral faults north of San Francisco that together accommodate much of the relative motion between the Pacific and North American tectonic plates. The South Napa event was the largest to have shaken the San Francisco Bay Area (SFBA) in almost 25 years. A major goal of the NSF-funded EarthScope Plate Boundary Observatory (PBO), installed and maintained by UNAVCO, was to enable researchers to study the interaction between the faults that form a plate boundary zone, and in particular, to investigate the role that aseismic transients contribute to strain accumulation and release. To realize this goal, PBO includes borehole tensor strainmeters (BSMs) installed in several targeted regions, including on to the north and east of San Francisco. Two PBO BSMs have been operating in the SFBA since 2008: B057, north of San Francisco and 30 km from the epicenter, and B054, 3 km from the Hayward Fault and 40 km from the epicenter. We find the coseismic strains recorded by B057 are close to those predicted using elastic half-space dislocation theory and the seismically determined focal mechanism, while a more complicated variable slip model may be required for observations from B054. Months after the event, B057 continued to record a significant postseismic signal. In this presentation we document the coseismic signals recorded by the PBO BSMs and characterize the temporal behavior of the postseismic signal at B057. The PBO network includes over 1100 GPS, 75 BSMs, 79 seismometers and arrays of tiltmeters, pore pressure sensors and meteorological instrumentation. UNAVCO generates an Earthscope Level 2 processed strain time-series combined into areal and shear strains for the PBO BSM network; the raw data are available from the IRIS DMC in mSEED format. For events of interest, such as the South Napa earthquake, UNAVCO generates a 1-sps

  13. Criticality features in ultra-low frequency magnetic fields prior to the 2013 M6.3 Kobe earthquake

    Directory of Open Access Journals (Sweden)

    Stelios M. Potirakis


    Full Text Available The nonlinear criticality of ultra-low frequency (ULF magnetic variations is investigated before a particular earthquake (EQ occurred in Kobe on April 12, 2013, by applying the “natural time” analysis on a few ULF parameters: Fh, Fz and Dh. The first two refer to radiation from the lithosphere, and the last parameter corresponds to depression of horizontal component as a signature of ionospheric perturbation. A recent paper of our team has indicated, using the same data as in this paper but by means of conventional statistical analysis, a clear effect of depression in the horizontal component as an ionospheric signature. But there seems to be no convincing signature of lithospheric ULF radiation according to the specific analysis, so this paper aims at extending our study on the electromagnetic data recorded prior to the specific EQ by trying to find any significant phenomenon in ULF effects (both lithospheric radiation and the depression of horizontal component using the critical, natural time analysis. The natural time analysis has yielded that criticality at Shigaraki (SGA, as the station closest to the EQ epicenter, is reached on March 27-29 for Fh and March 27 to April 1 for Fz (about two weeks before the EQ. But, the criticality for Dh was not observed at SGA probably due to high noise, on the other hand such criticality was observed at Kanoya (KNY because of its known property of a wider range of detection of ULF depression.

  14. Space conditions during a month of a sequence of six M > 6.8 earthquakes ending with the tsunami of 26 December 2004

    Directory of Open Access Journals (Sweden)

    A. Papandreou


    Full Text Available This paper examines space and seismological data for the time period about one month before the giant Sumatra-Andaman strong (9.3 earthquake (EQ. The combination of seismological and space data reveals some interesting features for this time period: (1 six successive high speed solar wind streams obviously triggering a sudden increase of geomagnetic activity were all followed by strong to giant (M > 6.8 EQs, (2 the 6 strong EQs present certain spatial-temporal constraints, with the epicentre of the EQs occuring at the edges of the Pacific Plate (the Sumatra-Andaman EQ occurred at the end of this series of EQs, eastward of the first one, in a clockwise direction, (3 the EQs occurred after a sudden increase of geomagnetic activity, as inferred from the 3 h-Kp index, following a quiet geomagnetic period and (4 the time delay of the M > 6.2 earthquakes (in the broad area examined from the last maximum sudden Kp increase was on average ~1.5 days. These findings from the study of the Earth's space environment during the month preceding the Sumatra-Andaman giant (9.3 EQ provide new information for a possible better understanding of the Sun-magnetosphere-lithosphere coupling.

  15. Numerical simulation of dynamic Coulomb stress changes induced by M6.5 earthquake in Wuding, Yunnan and its relationship with aftershocks

    Institute of Scientific and Technical Information of China (English)

    HU Xiong-lin; WU Xiao-ping; YANG Run-hai; FU Hong; HU Jia-fu; HUANG Yong


    Based on the discrete wavenumber method, we calculate the fields of dynamic Coulomb rupture stress changes and static stress changes caused by M6.5 earthquake in Wuding, and study their relationship with the subsequent aftershocks. The results show that the spatial distribution patterns of the positive region of dynamic stress peak value and static stress peak value are similarly asymmetric, which are basically identical with distribution features of aftershock. The dynamic stress peak value and the static stress in the positive region are more than 0.1 MPa and 0.01 MPa of the triggering threshold, respectively, which indicates that the dynamic and static stresses are helpful for the occurrence of aftershock. This suggests that both influences of dynamic and static stresses should be con-sidered other than only either of them when studying aftershock triggering in near field.

  16. Estimating the probability of occurrence of earthquakes (M>6) in the Western part of the Corinth rift using fault-based and classical seismotectonic approaches. (United States)

    Boiselet, Aurelien; Scotti, Oona; Lyon-Caen, Hélène


    -SISCOR Working Group. On the basis of this consensual logic tree, median probability of occurrences of M>=6 events were computed for the region of study. Time-dependent models (Brownian Passage time and Weibull probability distributions) were also explored. The probability of a M>=6.0 event is found to be greater in the western region compared to the eastern part of the Corinth rift, whether a fault-based or a classical seismotectonic approach is used. Percentile probability estimates are also provided to represent the range of uncertainties in the results. The percentile results show that, in general, probability estimates following the classical approach (based on the definition of seismotectonic source zones), cover the median values estimated following the fault-based approach. On the contrary, the fault-based approach in this region is still affected by a high degree of uncertainty, because of the poor constraints on the 3D geometries of the faults and the high uncertainties in their slip rates.

  17. Surface deformation due to the M6.5 Lefkada earthquake (17 November 2015) exploiting SENTINEL-1 and GNSS observations. Implications for seismic hazard. (United States)

    Elias, Panagiotis; Ganas, Athanassios; Briole, Pierre; Parcharidis, Isaak; Avallone, Antonio; Roukounakis, Nikos; Argyrakis, Panagiotis; Roger, Marine; Cheloni, Daniele; Tolomei, Cristiano; Mendonidis, Evangelos; Moraitini, Evelyn; Papanikolaou, Marios; Papastergios, Asterios


    The 17 November 2015 M=6.5 Lefkada earthquake in the Ionian sea, Greece, produced tens of centimetres of co-seismic motion in both Lefkada and Cephalonia islands. We present the full picture of the co-seismic displacements as mapped by space geodetic techniques, Sentinel 1A INSAR and permanent GNSS stations. We use this data together with the constraints from seismology to invert for fault localisation , size and slip distribution. We observed post-seismic displacements throughout most of southern Lefkada and northern Cephalonia islands recorded at the two NOA GNSS stations of PONT and SPAN and four additional permanent and six campaign GNSS stations established after the earthquake. Those displacements range from a few centimetres near the epicentre to a few millimetres far from the fault. We model the post-seismic displacements as due to uniform slip on the same fault plane that ruptured during the main event. The model shows a right-lateral afterslip along the fault but with slightly larger extension in comparison to the co-seismic slip, less shallow and deeper. This transient strain followed the main event during a short period of 80 days as modelled with an exponential law. Currently, the post-seismic deformation is being investigated by exploiting multi-temporal Sentinel 1A/B InSAR processed among others with ESA's Geohazards Exploitation Platform and SNAP software. The first challenging issue is the coherence which is not high in the area due to the vegetation cover. The second one is the correction of the tropospheric component. We estimate it using the tropospheric delay at the permanent GNSS stations and by using an meteorological model based on the WRF refined at the spatial resolution of 1 km. The earthquakes occurred in the Central Ionian area since 1983, studied both by seismology and space geodesy imply a seismic gap offshore NW Cephalonia that needs to be monitored.

  18. A stochastic estimate of ground motion at Oceano, California, for the M 6.5 22 December 2003 San Simeon earthquake, derived from aftershock recordings (United States)

    Di, Alessandro C.; Boatwright, J.


    The U.S. Geological Survey deployed a digital seismic station in Oceano, California, in February 2004, to investigate the cause of damage and liquefaction from the 22 December 2003 M 6.5 San Simeon earthquake. This station recorded 11 M > 2.8 aftershocks in almost 8 weeks. We analyze these recordings, together with recordings of the mainshock and the same aftershocks obtained from nearby stations in Park Hill and San Luis Obispo, to estimate the mainshock ground motion in Oceano. We estimate the Fourier amplitude spectrum using generalized spectral ratio analysis. We test a set of aftershocks as Green's functions by comparing simulated and recorded acceleration amplitude spectra for the mainshock at San Luis Obispo and Park Hill. We convolve the aftershock accelerograms with a stochastic operator to simulate the duration and phase of the mainshock accelerograms. This approximation allows us to extend the range of aftershocks that can be used as Green's functions to events nearly three magnitude units smaller than the mainshock. Our realizations for the mainshock accelerogram at Oceano yield peak ground accelerations distributed as 28% ?? 4%g. We interpret these realizations as upper bounds for the actual ground motion, because our analysis assumes a linear response, whereas the presence of liquefaction indicates that the ground behaved nonlinearly in Oceano.

  19. Afterslip-dominated surface rupture in the M6.0 South Napa Earthquake as constrained by structure-from-motion analysis and terrestrial laser scanning (United States)

    DeLong, S. B.; Pickering, A.; Scharer, K. M.; Hudnut, K. W.; Lienkaemper, J. J.


    Near-fault surface deformation associated with the August 24, 2014 M6.0 South Napa earthquake included both coseismic and post-seismic slip. Initial synthesis of field observations and initial measurement and modeling of afterslip from traditional survey methods indicate that coseismic slip was minimal (Road, on discontinuous left-stepping en echelon ruptures. By August 26, the surface rupture became nearly continuous, and cultural features extracted from the TLS point clouds indicate horizontal slip magnitudes between 15 and 27 cm, increasing northward. By September 22, slip magnitudes had increased to between 26 and 46 cm. The lower slip magnitudes are to the south at Withers Road, and the general trend is increased slip to the north, but there is more slip variability along the fault trace in the September 15 data. From August 26 to September 15, the west side of the fault trace uplifted between 0.5 and 5 cm relative to east side. Increased relief on the surface rupture itself indicated a slight compressional component of the deformation. These results confirm that post-event air photos can be useful for rapid 3D mapping, and that the unparalleled accuracy of TLS data can be used to quantify even very subtle deformation patterns in three dimensions and document changes through time.

  20. Damage Proxy Map from InSAR Coherence Applied to February 2011 M6.3 Christchurch Earthquake, 2011 M9.0 Tohoku-oki Earthquake, and 2011 Kirishima Volcano Eruption (United States)

    Yun, S.; Agram, P. S.; Fielding, E. J.; Simons, M.; Webb, F.; Tanaka, A.; Lundgren, P.; Owen, S. E.; Rosen, P. A.; Hensley, S.


    Under ARIA (Advanced Rapid Imaging and Analysis) project at JPL and Caltech, we developed a prototype algorithm to detect surface property change caused by natural or man-made damage using InSAR coherence change. The algorithm was tested on building demolition and construction sites in downtown Pasadena, California. The developed algorithm performed significantly better, producing 150 % higher signal-to-noise ratio, than a standard coherence change detection method. We applied the algorithm to February 2011 M6.3 Christchurch earthquake in New Zealand, 2011 M9.0 Tohoku-oki earthquake in Japan, and 2011 Kirishima volcano eruption in Kyushu, Japan, using ALOS PALSAR data. In Christchurch area we detected three different types of damage: liquefaction, building collapse, and landslide. The detected liquefaction damage is extensive in the eastern suburbs of Christchurch, showing Bexley as one of the most significantly affected areas as was reported in the media. Some places show sharp boundaries of liquefaction damage, indicating different type of ground materials that might have been formed by the meandering Avon River in the past. Well reported damaged buildings such as Christchurch Cathedral, Canterbury TV building, Pyne Gould building, and Cathedral of the Blessed Sacrament were detected by the algorithm. A landslide in Redcliffs was also clearly detected. These detected damage sites were confirmed with Google earth images provided by GeoEye. Larger-scale damage pattern also agrees well with the ground truth damage assessment map indicated with polygonal zones of 3 different damage levels, compiled by the government of New Zealand. The damage proxy map of Sendai area in Japan shows man-made structure damage due to the tsunami caused by the M9.0 Tohoku-oki earthquake. Long temporal baseline (~2.7 years) and volume scattering caused significant decorrelation in the farmlands and bush forest along the coastline. The 2011 Kirishima volcano eruption caused a lot of ash

  1. Tectonic Seasonal Loading Inferred from cGPS Measurements as a Potential Trigger for the M6.0 South Napa Earthquake (United States)

    Kraner, M.; Holt, W. E.; Borsa, A. A.


    Measurements from continuous global positioning system (cGPS) networks continue to unfold details about transient strain signals [Mavrommatis et al., 2014; Heki, 2003]. Linking these transient strain signals to seismic events remains elusive, as it requires detailed information about the steady-state tectonic loading sources, faulting geometries, and strain distribution with depth. Here we use cGPS measurements to uncover a regional strain transient peaking just prior to the M6.0 August 24, 2014 South Napa earthquake. This signal appears to have produced a coulomb stress increase, favoring slip on the West Napa faulting system. Analysis of cGPS time series during the interseismic period from 2006 to 2014 shows a stacked summer dilatational lobe of +142 ± 64 x 10-9 in the 100 km2 earthquake region. The Napa region is part of a broad, long wavelength, zone of positive dilatational strain and coulomb stress increase peaking each summer season. Summer transients are associated with horizontal displacements of 3-5 mm directed eastward toward the Sacramento Basin and of 1-3 mm directed southwest toward the San Francisco Bay and Pacific Ocean. Winter transients involve the opposite of these motions, causing negative dilatational strains and negative coulomb stress changes in the Napa region. We observe a significant increase in summer seismicity rates (greater than 95% confidence for a Chi-square test) within regions of positive coulomb stress change in Northern California. Large scale models of vertical hydrologic loading predict some components of the long-wavelength horizontal signal in Northern California, but this loading accounts for only 20 - 30% of the total anomalous signal. We hypothesize that the remaining signal is associated with smaller-scale seasonal groundwater fluctuations in local basins (e.g., the Sonoma and Napa sub-basins) along with thermoelastic effects. We provide details regarding the amount of thermoelastic strain from the elastic portion of the

  2. A Stochastic Estimate of Ground Motion at Oceano, California, for the M6.5 December 22, 2003, San Simeon Earthquake, Derived from Aftershock Recordings (United States)

    di Alessandro, C.; Boatwright, J.


    The U.S. Geological Survey deployed a digital seismic station in Oceano, California, in February 2004, to investigate the cause of damage and liquefaction from the 22 December 2003 M6.5 San Simeon earthquake. This station recorded 11 M\\> 2.8 aftershocks in almost eight weeks. We use these recordings, together with recordings of the main shock and the same aftershocks obtained from nearby stations in Park Hill and San Luis Obispo, to estimate the mainshock ground motion in Oceano. We estimate the Fourier amplitude spectrum using a generalized spectral ratio analysis that averages the spectral ratios from both stations for all the co-recorded aftershocks. We test three aftershocks as Green's functions by comparing simulated and recorded acceleration amplitude spectra for the main shock at Park Hill and San Luis Obispo. Instead of deconvolving the aftershock recordings from the mainshock recordings to estimate a source-time function, we convolve the aftershock accelerograms with a stochastic operator to simulate the duration and phase of the mainshock accelerograms. These stochastic operators are determined as sets of delta functions whose delays are randomly generated from a gamma distribution with a shape parameter of 1. We choose the scale parameter by fitting Husid plots of the Park Hill and San Luis Obsipo mainshock accelerograms. This stochastic approach allows us to extend the range of aftershocks that can be used as Green's functions to events nearly three magnitude units smaller than the main shock. Our realizations for the mainshock accelerogram at Oceano yield PGAs distributed as 28±4% g. We interpret these realizations as upper bounds for the actual ground motion because our analysis assumes that the ground behaved linearly, while the liquefaction and lateral spreading indicates that the ground behaved non-linearly. Geotechnical analysis of the site indicates that a PGA of 25% g would have initiated the liquefaction.

  3. Stress-based aftershock forecasts made within 24h post mainshock: Expected north San Francisco Bay area seismicity changes after the 2014M=6.0 West Napa earthquake (United States)

    Parsons, Thomas E.; Segou, Margaret; Sevilgen, Volkan; Milner, Kevin; Field, Ned; Toda, Shinji; Stein, Ross S.


    We calculate stress changes resulting from the M= 6.0 West Napa earthquake on north San Francisco Bay area faults. The earthquake ruptured within a series of long faults that pose significant hazard to the Bay area, and we are thus concerned with potential increases in the probability of a large earthquake through stress transfer. We conduct this exercise as a prospective test because the skill of stress-based aftershock forecasting methodology is inconclusive. We apply three methods: (1) generalized mapping of regional Coulomb stress change, (2) stress changes resolved on Uniform California Earthquake Rupture Forecast faults, and (3) a mapped rate/state aftershock forecast. All calculations were completed within 24 h after the main shock and were made without benefit of known aftershocks, which will be used to evaluative the prospective forecast. All methods suggest that we should expect heightened seismicity on parts of the southern Rodgers Creek, northern Hayward, and Green Valley faults.

  4. Stress-based aftershock forecasts made within 24 h postmain shock: Expected north San Francisco Bay area seismicity changes after the 2014 M = 6.0 West Napa earthquake (United States)

    Parsons, Tom; Segou, Margaret; Sevilgen, Volkan; Milner, Kevin; Field, Edward; Toda, Shinji; Stein, Ross S.


    We calculate stress changes resulting from the M = 6.0 West Napa earthquake on north San Francisco Bay area faults. The earthquake ruptured within a series of long faults that pose significant hazard to the Bay area, and we are thus concerned with potential increases in the probability of a large earthquake through stress transfer. We conduct this exercise as a prospective test because the skill of stress-based aftershock forecasting methodology is inconclusive. We apply three methods: (1) generalized mapping of regional Coulomb stress change, (2) stress changes resolved on Uniform California Earthquake Rupture Forecast faults, and (3) a mapped rate/state aftershock forecast. All calculations were completed within 24 h after the main shock and were made without benefit of known aftershocks, which will be used to evaluative the prospective forecast. All methods suggest that we should expect heightened seismicity on parts of the southern Rodgers Creek, northern Hayward, and Green Valley faults.

  5. Shallow reflection imaging by PSDM of dense, wide-aperture data: application to the causative fault of the 1980, M6.9, southern Italy earthquake (United States)

    Castiello, Antonio; Bruno, Pier Paolo; Improta, Luigi


    Shallow reflection imaging of active faults in unconsolidated deposits is a challenging task. Main factors hindering seismic imaging are the presence of steep-dipping reflectors and strong lateral velocity changes across the fault-zone, which often make standard CDP processing inappropriate. This drawback can be in principle overcome by Prestack Depth Migration (PSDM). However, performance of PSDM strongly relies on the availability of an accurate background velocity model, which is critical to account properly for the seismic wave propagation and ray-path bending in the depth domain. Such a velocity model cannot be obtained by standard seismic reflection acquisition geometries due to the small-aperture of the receiver/shot array and to the difficulty in collecting good-quality near-vertical reflection data in the very near-surface. Consequently, PSDM of shallow reflection data is very rare in the scientific literature. Recent applications of PSDM to very complex crustal structures have revealed that the use of non-conventional, dense wide-aperture acquisition geometries allows to successfully face the problem of the background velocity estimation. In this study, we investigate if the PSDM of dense, wide-aperture data can be an effective strategy for shallow imaging of complex structures, such as fault zone. We target the Irpinia Fault (IF), source of the 1980, M6.9, southern Italy normal-faulting earthquake. A 256 m long, ultrahigh resolution wide-aperture profile has been collected across the 1980 fault scarp in a small intermountain basin in the Southern Apennines range (Pantano di San Gregorio Magno). The source and receiver spacing is 3 m and 1.5 m, respectively, and the source is provided by a Buffalo gun. The survey aims at imaging the first 100 m of subsurface and at providing valuable information on the fault zone architecture below a collocated paleoseismic trench. The presence of unconsolidated deposits above a limestone basin substratum translates into

  6. The 11/25/88, M=6 Saguenay Earthquake near Chicoutimi, Quebec: Evidence for anisotropic wave propagation in northeastern North America (United States)

    Hough, S. E.; Jacob, K. H.; Friberg, P. A.


    On November 25, 1988, a magnitude 6 earthquake occurred in the province of Quebec, Canada. This earthquake triggered nine digital strong motion instruments in New York and Maine at epicentral distances of 200 to 820 km which were installed as part of an effort by the National Center for Earthquake Engineering Research (NCEER) to study ground motions and wave propagation in eastern North America. We calculate Q(f) at discrete frequencies from 0.6 to 26 Hz, assuming that geometrical spreading causes a l/r0.5 decay in spectral amplitudes. Of the nine stations, four are in the Adirondack Mountains in New York and three are in eastern Maine. If we calculate Q(f) for these two clusters of stations separately, we obtain higher values for the Adirondack stations. The Quebec-Adirondack path is along the strike of the predominant structural trends in northeastern North America, in the Grenville Province crust, while the Quebec-Maine path is at high angle to the structural grain and crosses the boundary between the Grenville and the Appalachian provinces. We thus have instrumental data in support of earlier observations based on contours of intensity from historic earthquakes: Seismic wave propagation in northeastern North America is more efficient along the predominantly NE-SW striking geological trends. We address possible biases due to site effects.

  7. Time-dependent neo-deterministic seismic hazard scenarios: Preliminary report on the M6.2 Central Italy earthquake, 24th August 2016

    CERN Document Server

    Peresan, Antonella; Romashkova, Leontina; Magrin, Andrea; Soloviev, Alexander; Panza, Giuliano F


    A scenario-based Neo-Deterministic approach to Seismic Hazard Assessment (NDSHA) is available nowadays, which permits considering a wide range of possible seismic sources as the starting point for deriving scenarios by means of full waveforms modeling. The method does not make use of attenuation relations and naturally supplies realistic time series of ground shaking, including reliable estimates of ground displacement, readily applicable to complete engineering analysis. Based on the neo-deterministic approach, an operational integrated procedure for seismic hazard assessment has been developed that allows for the definition of time dependent scenarios of ground shaking, through the routine updating of earthquake predictions, performed by means of the algorithms CN and M8S. The integrated NDSHA procedure for seismic input definition, which is currently applied to the Italian territory, combines different pattern recognition techniques, designed for the space-time identification of strong earthquakes, with al...

  8. Tearing the terroir: Details and implications of surface rupture and deformation from the 24 August 2014 M6.0 South Napa earthquake, California (United States)

    DeLong, Stephen B.; Donnellan, Andrea; Ponti, Daniel J.; Rubin, Ron S.; Lienkaemper, James J.; Prentice, Carol S.; Dawson, Timothy E.; Seitz, Gordon G.; Schwartz, David P.; Hudnut, Kenneth W.; Rosa, Carla M.; Pickering, Alexandra J; Parker, Jay W.


    The Mw 6.0 South Napa earthquake of 24 August 2014 caused slip on several active fault strands within the West Napa Fault Zone (WNFZ). Field mapping identified 12.5 km of surface rupture. These field observations, near-field geodesy and space geodesy, together provide evidence for more than ~30 km of surface deformation with a relatively complex distribution across a number of subparallel lineaments. Along a ~7 km section north of the epicenter, the surface rupture is confined to a single trace that cuts alluvial deposits, reoccupying a low-slope scarp. The rupture continued northward onto at least four other traces through subparallel ridges and valleys. Postseismic slip exceeded coseismic slip along much of the southern part of the main rupture trace with total slip 1 year postevent approaching 0.5 m at locations where only a few centimeters were measured the day of the earthquake. Analysis of airborne interferometric synthetic aperture radar data provides slip distributions along fault traces, indicates connectivity and extent of secondary traces, and confirms that postseismic slip only occurred on the main trace of the fault, perhaps indicating secondary structures ruptured as coseismic triggered slip. Previous mapping identified the WNFZ as a zone of distributed faulting, and this was generally borne out by the complex 2014 rupture pattern. Implications for hazard analysis in similar settings include the need to consider the possibility of complex surface rupture in areas of complex topography, especially where multiple potentially Quaternary-active fault strands can be mapped.

  9. Olivetti M6 640

    CERN Multimedia


    The M6-640 is the highest performance personal computer workstation in the Suprema range with multimedia, document imaging and communications capabilities. It has a 90MHz Pentium processor with 256Kb of secondary cache. It can accommodate up to 128Mb RAM and supports hard disks of up to 1Gb through an IDE interface.

  10. Local Postseismic Relaxation Observed After the 1992 Landers (M=7.3), 1999 Hector Mine (M=7.1), 2002 Denali (M=7.9), and 2003 San Simeon (M=6.5) Earthquakes (United States)

    Svarc, J. L.; Savage, J. C.


    The U. S. Geological Survey has observed the local postseismic deformation following the 1992 Landers (M=7.3), 1999 Hector Mine (M=7.1), 2002 Denali (M=7.9), and 2003 San Simeon (M=6.5) earthquakes. The observations consist of repeated campaign-style GPS surveys of geodetic arrays (aperture ˜ 50 km) in the epicentral area of each earthquake. The data span the intervals from 0.037 to 5.6, 0.0025 to 4.5, 0.022 to 1.6, and 0.005 to 0.55 yr postearthquake for the Landers, Hector Mine, Denali, and San Simeon earthquakes, respectively. We have reduced the observations to positions of the monuments measured relative to another monument within the array. The temporal dependence of the relative displacements for each monument can be approximated by a+bt+c(1-exp[-t/d]) where a, b, c, and d are constants particular to that monument and t is the time after the earthquake. The relaxation times d were found to be 0.367±0.062, 0.274±0.024, 0.145±0.017, and 0.032±0.002 yr for the Landers, Hector Mine, Denali, and San Simeon earthquakes, respectively. The observed increase in d with the duration of the time series fit suggests that the relaxation process involves more than a single relaxation time. An alternative function a'+b't+c'log(1+t/d') where a', b', c', and d' are constants particular to each monument furnishes a better fit to the data. This logarithmic form of the relaxation (Lomnitz creep function), identical to the calculated response of a simple spring-slider system subject to rate-state friction [Marone et al., 1991], contains a continuous spectrum of relaxation times. In fitting data the time constant d' is determined by observations within the first few days postseismic and consequently is poorly defined. Adequate fits to the data are found by simply setting d'=0.001 yr and determining a', b', and c' by linear least squares. That the temporal dependence is so readily fit by both exponential and logarithmic functions suggests that the temporal dependence by itself

  11. Seismological evidence of an active footwall shortcut thrust in the Northern Itoigawa-Shizuoka Tectonic Line derived by the aftershock sequence of the 2014 M 6.7 Northern Nagano earthquake (United States)

    Panayotopoulos, Yannis; Hirata, Naoshi; Hashima, Akinori; Iwasaki, Takaya; Sakai, Shin'ichi; Sato, Hiroshi


    A destructive M 6.7 earthquake struck Northern Nagano prefecture on November 22, 2014. The main shock occurred on the Kamishiro fault segment of the northern Itoigawa-Shizuoka Tectonic Line (ISTL). We used data recorded at 41 stations of the local seismographic network in order to locate 2118 earthquakes that occurred between November 18 and November 30, 2014. To estimate hypocenters, we assigned low Vp models to stations within the Northern Fossa Magna (NFM) basin thus accounting for large lateral crustal heterogeneities across the Kamishiro fault. In order to further improve accuracy, the final hypocenter locations were recalculated inside a 3D velocity model using the double-difference method. We used the aftershock activity distribution and focal mechanism solutions of major events in order to estimate the source fault area of the main shock. Our analysis suggests that the shallow part of the source fault corresponds to the surface trace of the Kamishiro fault and dips 30°-45° SE, while the deeper part of the source fault corresponds to the downdip portion of the Otari-Nakayama fault, a high angle fault dipping 50°-65° SE that formed during the opening of the NFM basin in the Miocene. Along its surface trace the Otari-Nakayama fault has been inactive during the late Quaternary. We verified the validity of our model by calculating surface deformation using a simple homogeneous elastic half-space model and comparing it to observed surface deformation from satellite interferometry, assuming large coseismic slip in the areas of low seismicity and small coseismic slip in the areas of high seismicity. Shallowing of the source fault from 50°-65° to 30°-45° in the upper 4 km, in the areas where both surface fault traces are visible, is a result of footwall shortcut thrusting by the Kamishiro fault off the Otari-Nakayama fault.

  12. Ultrashallow seismic imaging of the causative fault of the 1980, M6.9, southern Italy earthquake by pre-stack depth migration of dense wide-aperture data (United States)

    Bruno, Pier Paolo; Castiello, Antonio; Improta, Luigi


    A two-step imaging procedure, including pre-stack depth migration (PSDM) and non-linear multiscale refraction tomography, was applied to dense wide-aperture data with the aim of imaging the causative fault of the 1980, M6.9, Irpinia normal faulting earthquake in a very complex geologic environment. PSDM is often ineffective for ultrashallow imaging (100 m of depth and less) of laterally heterogeneous media because of the difficulty in estimating a correct velocity model for migration. Dense wide-aperture profiling allowed us to build accurate velocity models across the fault zone by multiscale tomography and to record wide-angle reflections from steep reflectors. PSDM provided better imaging with respect to conventional post-stack depth migration, and improved definition of fault geometry and apparent cumulative displacement. Results indicate that this imaging strategy can be very effective for near-surface fault detection and characterization. Fault location and geometry are in agreement with paleoseismic data from two nearby trenches. The estimated vertical fault throw is only 29-38 m. This value, combined with the vertical slip rate determined by trench data, suggests a young age (97-127 kyr) of fault inception.

  13. Coseismic water level changes induced by two distant earthquakes in multiple wells of the Chinese mainland (United States)

    Ma, Yuchuan; Huang, Fuqiong


    Coseismic water level oscillations, or step-like rises and step-like drops were recorded in 159 wells throughout the Chinese mainland due to the 2015 Nepal Mw 7.8 earthquake, and 184 wells for the 2011 Japan Mw 9.0 earthquake. The earthquake magnitude, and the associated dynamic stresses, has positive roles in both the sensitivity of water level to earthquake induced change, and the amplitude and duration of resulting coseismic water level changes. Wells whose water levels are sensitive to Earth tides have high potential to response to earthquakes. Polarities of step-like changes (rises or drops) are locally controlled and spatially variable, with artesian wells generally recording water-level rises. Permeability enhancement was assessed as a mechanism responsible for step-like changes by analyzing the tidal phase responses. Permeability variations are inferred for 17 out of 95 wells with step-like changes during the Nepal earthquake and for 32 out of 105 wells following the Japan earthquake; however, only 6 wells have permeability variations after both earthquakes.

  14. Ionospheric anomalies related to the (M = 7.3), August 27, 2012, Puerto earthquake, (M = 6.8), August 30, 2012 Jan Mayen Island earthquake, and (M = 7.6), August 31, 2012, Philippines earthquake: two-dimensional principal component analysis. (United States)

    Lin, Jyh-Woei


    Two-dimensional principal component analysis (2DPCA) and principal component analysis (PCA) are used to examine the ionospheric total electron content (TEC) data during the time period from 00:00 on August 21 to 12: 45 on August 31 (UT), which are 10 days before the M = 7.6 Philippines earthquake at 12:47:34 on August 31, 2012 (UT) with the depth at 34.9 km. From the results by using 2DPCA, a TEC precursor of Philippines earthquake is found during the time period from 4:25 to 4:40 on August 28, 2012 (UT) with the duration time of at least 15 minutes. Another earthquake-related TEC anomaly is detectable for the time period from 04:35 to 04:40 on August 27, 2012 (UT) with the duration time of at least 5 minutes during the Puerto earthquake at 04: 37:20 on August 27, 2012 (UT) (M(w) = 7.3) with the depth at 20.3 km. The precursor of the Puerto earthquake is not detectable. TEC anomaly is not to be found related to the Jan Mayen Island earthquake (M w = 6.8) at 13:43:24 on August 30, 2012 (UT). These earthquake-related TEC anomalies are detectable by using 2DPCA rather than PCA. They are localized nearby the epicenters of the Philippines and Puerto earthquakes.

  15. How Well Do Earthquake Hazard Maps Work and How Good Do They Have to be? (United States)

    Brooks, E.; Stein, S. A.; Spencer, B. D.


    Earthquake hazard maps seek to describe the level of earthquake hazards in a region and provide a scientific foundation for earthquake preparation and mitigation. In many cases these maps do reasonably well. However, recent large earthquakes that did great damage in areas predicted to be relatively safe illustrate the need to assess how well these maps are actually performing and how good they need to be to be useful. Economic analysis comparing the cost of mitigation to the expected reduction in loss shows that an inaccurate hazard estimate still is useful as long as it is not too much of an overestimate. Because better hazard forecasts can yield better mitigation policy, we need agreed ways of assessing how well a map performed and thus whether one map performed better than another. The metric implicit in current maps, that during the chosen time interval the predicted ground motion will be exceeded only at a specific fraction of the sites, is useful but permits maps to be nominally successful although they significantly underpredict or overpredict shaking, or to be nominally unsuccessful but do well in terms of predicting shaking. We explore some possible metrics that better measure the effects of overprediction and underprediction and can be weighted to reflect the two differently and to reflect differences in populations and property at risk. Although no single metric alone fully characterizes map behavior, using several metrics can provide useful insight for comparing and improving hazard maps.

  16. Geotechnical Extreme Events Reconnaissance Report on the Performance of Structures in Densely Urbanized Areas Affected by Surface Fault Rupture During the August 24, 2014 M6 South Napa Earthquake, California, USA. (United States)

    Cohen-Waeber, J.; Lanzafame, R.; Bray, J.; Sitar, N.


    The August 24, 2014, M­w 6.0 South Napa earthquake is the largest seismic event to have occurred in the San Francisco Bay Region, California, USA, since the Mw 6.9 1989 Loma Prieta earthquake. The event epicenter occurred at the South end of the Napa Valley, California, principally rupturing northwest along parts of the active West Napa fault zone. Bound by two major fault zones to the East and West (Calaveras and Rogers Creek, respectively), the Napa Valley is filled with up to 170 m. of alluvial deposits and is considered to be moderately to very highly susceptible to liquefaction and has the potential for violent shaking. While damage due to strong ground shaking was significant, remarkably little damage due to liquefaction or landslide induced ground deformations was observed. This may be due to recent drought in the region. Instead, the South Napa earthquake is the first to produce significant surface rupture in this area since the Mw 7.9 1906 San Andreas event, and the first in Northern California to rupture through a densely urbanized environment. Clear expressions of surface fault rupture extended approximately 12 - 15 km northward from the epicenter and approximately 1-2 km southeast with a significant impact to infrastructure, including roads, lifelines and residential structures. The National Science Foundation funded Geotechnical Extreme Events Reconnaissance (GEER) Association presents here its observations on the performance of structures affected by surface fault rupture, in a densely populated residential neighborhood located approximately 10 km north of the epicenter. Based on the detailed mapping of 27 residential structures, a preliminary assessment of the quantitative descriptions of damage shows certain characteristic interactions between surface fault rupture and the overlying infrastructure: 48% of concrete slabs cracked up to 8 cm wide, 19% of structures shifted up to 11 cm off of their foundation and 44% of foundations cracked up to 3 cm

  17. Earthquake

    Institute of Scientific and Technical Information of China (English)


    正A serious earthquake happened in Wenchuan, Sichuan. Over 60,000 people died in the earhtquake, millins of people lost their homes. After the earthquake, people showed their love in different ways. Some gave food, medicine and everything necessary, some gave money,

  18. Two-year survey comparing earthquake activity and injection-well locations in the Barnett Shale, Texas. (United States)

    Frohlich, Cliff


    Between November 2009 and September 2011, temporary seismographs deployed under the EarthScope USArray program were situated on a 70-km grid covering the Barnett Shale in Texas, recording data that allowed sensing and locating regional earthquakes with magnitudes 1.5 and larger. I analyzed these data and located 67 earthquakes, more than eight times as many as reported by the National Earthquake Information Center. All 24 of the most reliably located epicenters occurred in eight groups within 3.2 km of one or more injection wells. These included wells near Dallas-Fort Worth and Cleburne, Texas, where earthquakes near injection wells were reported by the media in 2008 and 2009, as well as wells in six other locations, including several where no earthquakes have been reported previously. This suggests injection-triggered earthquakes are more common than is generally recognized. All the wells nearest to the earthquake groups reported maximum monthly injection rates exceeding 150,000 barrels of water per month (24,000 m(3)/mo) since October 2006. However, while 9 of 27 such wells in Johnson County were near earthquakes, elsewhere no earthquakes occurred near wells with similar injection rates. A plausible hypothesis to explain these observations is that injection only triggers earthquakes if injected fluids reach and relieve friction on a suitably oriented, nearby fault that is experiencing regional tectonic stress. Testing this hypothesis would require identifying geographic regions where there is interpreted subsurface structure information available to determine whether there are faults near seismically active and seismically quiescent injection wells.

  19. 安居富民工程在地震灾害中的减灾效益初探--以2012年新疆新源、和静交界6.6级地震为例%Research on Disaster Reduction Benefit of Earthquake Resistant Project---Taking the M6.6 Earthquake in Xinyuan-Hejing Junction in 2012 for an Example

    Institute of Scientific and Technical Information of China (English)

    刘军; 宋立军; 胡伟华; 李志强; 谭明


    Earthquake damage characteristics the M6.6 Earthquake in Xinyuan-Hejing Junction on June 30, 2012 are introduced.Damage characteristics especially of the welfarehousing are studied as references.Earthquake damage cases of hazard bearing bodies before the earthquake resistant project in the same intensity of earthquake damage are derived by the seismic damage model.Parameters as damage area,number of casualties,homeless peo-ple and direct economic loss of houses of various types of housing are calculated and compared with the field data in the earthquake.The results show that,earthquake resistant project could ensure the safety of people′s lives and property in a destructive earthquake.Compared to the previous construction investment,the engineering is of obvi-ous mitigation benefits.%介绍了2012年6月30日新疆新源、和静交界6.6级地震的震害特征,并以此次地震中安居房的震害的为参照,通过模型反导出灾区在安居富民工程改造前同等强度地震破坏情形下承灾体的震害,分别计算了安居工程实施前各类房屋破坏面积、死伤人数、失去住所人数和房屋直接经济损失等参数,并与现场调查的安居房在此次地震中的震害进行对比分析。结果表明,安居富民工程在破坏性地震中为人民生命财产安全的保障及政府的救灾投入的统筹发挥着重要作用,相对于前期建设投资,安居富民工程具有显著的减灾效益。

  20. A repeating source of infrasound from the Wells, Nevada earthquake sequence

    Energy Technology Data Exchange (ETDEWEB)

    Arrowsmith, Stephen J. [Los Alamos National Laboratory; Whitaker, Rod [Los Alamos National Laboratory; Randall, George [Los Alamos National Laboratory; Burlacu, Relu [UNIV OF UTAH


    The Wells, Nevada earthquake of February 21, 2008, generated a complex seismoacoustic wakefield. In addition to epicentral infrasound, the earthquake triggered a secondary source of infrasound, which was also initiated by subsequent aftershocks. By applying simple constraints on the propagation of seismic and infrasound waves, we show that the secondary source is an isolated peak that appears to efficiently generate infrasound through the interaction with seismic surface waves. By measuring peak-to-peak amplitudes of epicentral and secondary arrivals and correcting them for the effects of distance and winds, we find that epicentral arrivals lit with empirical relationships of Mutschlecner and Whitaker (2005) and Le Pichon et al. (2006), which form the basis for a proposed infrasound discriminant (Anderson et al., Pers. Comm.). In contrast, the secondary arrivals are much higher in amplitude, highlighting the importance of being able to separate epicentral and secondary arrivals for infrasonic event discrimination.

  1. Determination of stress parameters for eight well-recorded earthquakes in eastern North America (United States)

    Boore, D.M.; Campbell, K.W.; Atkinson, G.M.


    We determined the stress parameter, Δσ, for the eight earthquakes studied by Atkinson and Boore (2006), using an updated dataset and a revised point-source stochastic model that captures the effect of a finite fault. We consider four geometrical-spreading functions, ranging from 1/R at all distances to two- or three-part functions. The Δσ values are sensitive to the rate of geometrical spreading at close distances, with 1/R1.3 spreading implying much higher Δσ than models with 1/R spreading. The important difference in ground motions of most engineering concern, however, arises not from whether the geometrical spreading is 1/R1.3 or 1/R at close distances, but from whether a region of flat or increasing geometrical spreading at intermediate distances is present, as long as Δσ is constrained by data that are largely at distances of 100 km–800 km. The simple 1/R model fits the sparse data for the eight events as well as do more complex models determined from larger datasets (where the larger datasets were used in our previous ground-motion prediction equations); this suggests that uncertainty in attenuation rates is an important component of epistemic uncertainty in ground-motion modeling. For the attenuation model used by Atkinson and Boore (2006), the average value of Δσ from the point-source model ranges from 180 bars to 250 bars, depending on whether or not the stress parameter from the 1988 Saguenay earthquake is included in the average. We also find that Δσ for a given earthquake is sensitive to its moment magnitude M, with a change of 0.1 magnitude units producing a factor of 1.3 change in the derived Δσ.

  2. The ShakeMaps of the Amatrice, M6, earthquake

    National Research Council Canada - National Science Library

    Licia Faenza; Valentino Lauciani; Alberto Michelini


    In this paper we describe the performance of the ShakeMap software package and the fully automatic procedure, based on manually revised location and magnitude, during the main event of the Amatrice...

  3. Coseismic responses of groundwater levels in the Three Gorges well-network to the Wenchuan Ms8.0 earthquake

    Institute of Scientific and Technical Information of China (English)

    Chenglong Liu; Guangcai Wang; Weihua Zhang; Jiangchang Mei


    We systematically analyze coseismic responses and post-seismic characteristics of groundwater levels in the Three Gorges well-network to the Afs8.0 Wenchuan earthquake on 12 May 2008. The results indicate that these characteristics differ among wells. On the conditions of similar borehole configurations, the differences are associated with geological structural sites of wells, burial types of aquifers monitored, and transmissivities of aquifer systems. We explored coseismic and post-seismic step-rise and step-drop mechanical mechanisms and their implication to earthquake prediction. We validated the inference that the residual step-rise zone is a possible earthquake risk zone based on recent seismic activity on the Xianniishan fault in the area.

  4. Astronomical alignments as the cause of ~M6+ seismicity

    CERN Document Server

    Omerbashich, Mensur


    I here demonstrate empirically my georesonator concept in which tidally induced magnification of Earth masses' resonance causes seismicity. To that end, I show that all strong (~M6+) earthquakes of 2010 occurred during the Earth's long (t>3 day) astronomical alignments within our solar system. I then show that the same holds true for all very strong (~M8+) earthquakes of the decade of 2000s. Finally, the strongest (M8.6+) earthquakes of the past century are shown to have occurred during the Earth's multiple long alignments, whereas half of the high-strongest (M9+) ones occurred during the Full Moon. I used the comet C/2010 X1 (Elenin), as it has been adding to robustness in terms of very strong seismicity since 2007 (in terms of strongest seismicity: since 1965). The Elenin will continue intensifying the Earth's very strong seismicity until August-October, 2011. Approximate forecast of earthquakes based on my discoveries is feasible. This demonstration proves my hyperresonator concept, arrived at earlier as a...

  5. The 2008 Wells, Nevada earthquake sequence: Source constraints using calibrated multiple event relocation and InSAR (United States)

    Nealy, Jennifer; Benz, Harley M.; Hayes, Gavin; Berman, Eric; Barnhart, William


    The 2008 Wells, NV earthquake represents the largest domestic event in the conterminous U.S. outside of California since the October 1983 Borah Peak earthquake in southern Idaho. We present an improved catalog, magnitude complete to 1.6, of the foreshock-aftershock sequence, supplementing the current U.S. Geological Survey (USGS) Preliminary Determination of Epicenters (PDE) catalog with 1,928 well-located events. In order to create this catalog, both subspace and kurtosis detectors are used to obtain an initial set of earthquakes and associated locations. The latter are then calibrated through the implementation of the hypocentroidal decomposition method and relocated using the BayesLoc relocation technique. We additionally perform a finite fault slip analysis of the mainshock using InSAR observations. By combining the relocated sequence with the finite fault analysis, we show that the aftershocks occur primarily updip and along the southwestern edge of the zone of maximum slip. The aftershock locations illuminate areas of post-mainshock strain increase; aftershock depths, ranging from 5 to 16 km, are consistent with InSAR imaging, which shows that the Wells earthquake was a buried source with no observable near-surface offset.

  6. The (Un)Productivity of the 2014 M6.0 South Napa Aftershock Sequence (United States)

    Llenos, A. L.


    The M6.0 South Napa mainshock produced fewer aftershocks than expected for a California earthquake of its magnitude, which became apparent a few days into the sequence. In the first 4.5 days, only 59 M≥1.8 aftershocks had occurred, the largest of which was a M3.9 that happened a little over two days after the mainshock. In contrast, during the same time period the 2004 M6.0 Parkfield earthquake had over 220 M≥1.8 aftershocks, 6 of which were M≥4. Here I investigate the aftershock productivity and other sequence statistics of the South Napa sequence and compare it with other M~6 California mainshock-aftershock sequences. By focusing on similar size events, they have similar finite extents within the seismotectonic environment. While the productivities of these sequences vary quite a bit, the b-values of the magnitude-frequency distributions all fall in the 0.6-0.8 range for the northern California sequences, slightly lower than the b-value of ~1 typical of southern California seismicity. Despite the relatively low productivity of the South Napa sequence, I show that the Epidemic-Type Aftershock Sequence (ETAS) model (Ogata, JASA, 1988) describes the sequence well and investigate whether the ETAS model parameters suggest that low-productivity sequences are typical for the region. I also explore how quickly after a mainshock these types of models can capture the low productivity of the sequence. The productivity of a sequence is a critical parameter in determining the aftershock probabilities reported in the days following the mainshock. Therefore, the sooner an accurate representation of the aftershock productivity can be obtained, the sooner more accurate aftershock probability reports can be produced.

  7. Determination of the relationship between radon anomalies and earthquakes in well waters on the Akşehir-Simav Fault System in Afyonkarahisar province, Turkey. (United States)

    Ali Yalım, Hüseyin; Sandıkcıoğlu, Ayla; Ertuğrul, Oğuz; Yıldız, Ahmet


    Radon concentrations were measured in water of 4 wells on the Akşehir-Simav Fault System (ASFS) in Afyonkarahisar province from August 2009 to September 2010 and the relationship between radon anomalies and earthquake magnitudes was examined. Anomalous decreases in radon concentrations in the wells were observed to precede the earthquakes of magnitudes ranging from 2.6 M to 3.9 M. The correlation coefficients (R(2)) were 0.79, 0.93, 0.98 and 0.90 for the wells from 1 to 4, respectively, indicating that radon minima and earthquake magnitude were well correlated and suggesting that the groundwater radon, when observed at suitable sites, can be a sensitive tracer for strain changes in crust associated with earthquake occurrences. The relationship between the two parameters can be further improved as additional radon anomalies precursor to possible large earthquakes are recorded in the wells located on the ASFS in the future. This study strongly suggests that the continuous observations of radon concentrations in well water, especially at well 3, should be carried forward.

  8. Spatial Evaluation and Verification of Earthquake Simulators (United States)

    Wilson, John Max; Yoder, Mark R.; Rundle, John B.; Turcotte, Donald L.; Schultz, Kasey W.


    In this paper, we address the problem of verifying earthquake simulators with observed data. Earthquake simulators are a class of computational simulations which attempt to mirror the topological complexity of fault systems on which earthquakes occur. In addition, the physics of friction and elastic interactions between fault elements are included in these simulations. Simulation parameters are adjusted so that natural earthquake sequences are matched in their scaling properties. Physically based earthquake simulators can generate many thousands of years of simulated seismicity, allowing for a robust capture of the statistical properties of large, damaging earthquakes that have long recurrence time scales. Verification of simulations against current observed earthquake seismicity is necessary, and following past simulator and forecast model verification methods, we approach the challenges in spatial forecast verification to simulators; namely, that simulator outputs are confined to the modeled faults, while observed earthquake epicenters often occur off of known faults. We present two methods for addressing this discrepancy: a simplistic approach whereby observed earthquakes are shifted to the nearest fault element and a smoothing method based on the power laws of the epidemic-type aftershock (ETAS) model, which distributes the seismicity of each simulated earthquake over the entire test region at a decaying rate with epicentral distance. To test these methods, a receiver operating characteristic plot was produced by comparing the rate maps to observed m>6.0 earthquakes in California since 1980. We found that the nearest-neighbor mapping produced poor forecasts, while the ETAS power-law method produced rate maps that agreed reasonably well with observations.

  9. Spatial Evaluation and Verification of Earthquake Simulators (United States)

    Wilson, John Max; Yoder, Mark R.; Rundle, John B.; Turcotte, Donald L.; Schultz, Kasey W.


    In this paper, we address the problem of verifying earthquake simulators with observed data. Earthquake simulators are a class of computational simulations which attempt to mirror the topological complexity of fault systems on which earthquakes occur. In addition, the physics of friction and elastic interactions between fault elements are included in these simulations. Simulation parameters are adjusted so that natural earthquake sequences are matched in their scaling properties. Physically based earthquake simulators can generate many thousands of years of simulated seismicity, allowing for a robust capture of the statistical properties of large, damaging earthquakes that have long recurrence time scales. Verification of simulations against current observed earthquake seismicity is necessary, and following past simulator and forecast model verification methods, we approach the challenges in spatial forecast verification to simulators; namely, that simulator outputs are confined to the modeled faults, while observed earthquake epicenters often occur off of known faults. We present two methods for addressing this discrepancy: a simplistic approach whereby observed earthquakes are shifted to the nearest fault element and a smoothing method based on the power laws of the epidemic-type aftershock (ETAS) model, which distributes the seismicity of each simulated earthquake over the entire test region at a decaying rate with epicentral distance. To test these methods, a receiver operating characteristic plot was produced by comparing the rate maps to observed m>6.0 earthquakes in California since 1980. We found that the nearest-neighbor mapping produced poor forecasts, while the ETAS power-law method produced rate maps that agreed reasonably well with observations.

  10. Analog earthquakes

    Energy Technology Data Exchange (ETDEWEB)

    Hofmann, R.B. [Center for Nuclear Waste Regulatory Analyses, San Antonio, TX (United States)


    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.

  11. Facts relating to Well No. 5, Lease OCS-P 0234, Pitas Point Unit area, and the earthquake of August 13, 1978, Santa Barbara Channel, California (United States)

    Wayland, Russell G.; Acuff, A. Dewey; McCulloh, Thane M.; Raleigh, C. Barry; Vedder, John G.; Yenne, Keith A.


    A build-up of pressures developed in an exploratory well being drilled in the Santa Barbara Channel during the period August 9 to 15, 1978. Nearly coincidentally, a sharp earthquake occurred 2 miles south of the city of Santa Barbara at 3:55 p.m. PDT on August 13, 1978. A task group was formed by the Director, Geological Survey, on August 14, mainly because of concern over the high down-hole pressures in the well. The charge to the task group was to study the situation fully in order that appropriate and immediate measures could be directed to protect against a fracturing of rock formations in the vicinity of the hole that might permit the escape of gas or oil to the surface. The task group was also asked to look into the possibility of any relationship between the well problems and the earthquake.

  12. Chromosomal mapping of the human M6 genes

    Energy Technology Data Exchange (ETDEWEB)

    Olinsky, S.; Loop, B.T.; DeKosky, A. [Univ. of Pittsburgh, PA (United States)] [and others


    M6 is a neuronal membrane glycoprotein that may have an important role in neural development. This molecule was initially defined by a monoclonal antibody that affected the survival of cultured cerebellar neurons and the outgrowth of neurites. The nature of the antigen was discovered by expression cDNA cloning using this monoclonal antibody. Two distinct murine M6 cDNAs (designated M6a and M6b) whose deduced amino acid sequences were remarkably similar to that of the myelin proteolipid protein human cDNA and genomic clones encoding M6a and M6b and have characterized them by restriction mapping, Southern hybridization with cDNA probes, and sequence analysis. We have localized these genes within the human genome by FISH (fluorescence in situ hybridization). The human M6a gene is located at 4q34, and the M6b gene is located at Xp22.2 A number of human neurological disorders have been mapped to the Xp22 region, including Aicardi syndrome (MIM 304050), Rett syndrome (MIM 312750), X-linked Charcot-Marie-Tooth neuropathy (MIM 302801), and X-linked mental retardation syndromes (MRX1, MIM 309530). This raises the possibility that a defect in the M6b gene is responsible for one of these neurological disorders. 8 refs., 3 figs.

  13. Strong motions and engineering structure performances in recent major earthquakes

    Institute of Scientific and Technical Information of China (English)

    Xiaojun Li


    @@ In recent years, a series of major earthquakes occurred, which resulted in considerable engineering damage and collapse, triggered heavy geological hazards, and caused extremely high casualties and huge property and economic loss. The earthquakes include the 1994 Northridge earthquake (M6.8), the 1995 Kobe earthquake (M6.8), the 1999 Izmit earthquake (M7.6), the 1999 Jiji (Chi-Chi) earthquake (M7.6), the 2005 northern Pakistan earthquake (M7.6), the 2008 Wenchuan earthquake (M8.0) and the 2010 Haiti earthquake (M7.0). Some villages, towns and even cities were devastated in the earthquakes, especially in the 2005 northern Pakistan earthquake, the 2008 Wenchuan earthquake and the 2010 Haiti earthquake.

  14. Deep postseismic viscoelastic relaxation excited by an intraslab normal fault earthquake in the Chile subduction zone (United States)

    Bie, Lidong; Ryder, Isabelle; Métois, Marianne


    The 2005 Mw 7.8 Tarapaca earthquake was the result of normal faulting on a west-dipping plane at a depth of 90 km within the subducting slab down-dip of the North Chilean gap that partially ruptured in the 2014 M 8.2 Iquique earthquake. We use Envisat observations of nearly four years of postseismic deformation following the earthquake, together with some survey GPS measurements, to investigate the viscoelastic relaxation response of the surrounding upper mantle to the coseismic stress. We constrain the rheological structure by testing various 3D models, taking into account the vertical and lateral heterogeneities in viscosity that one would expect in a subduction zone environment. A viscosity of 4-8 × 1018 Pa s for the continental mantle asthenosphere fits both InSAR line-of-sight (LOS) and GPS horizontal displacements reasonably well. In order to test whether the Tarapaca earthquake and associated postseismic relaxation could have triggered the 2014 Iquique sequence, we computed the Coulomb stress change induced by the co- and postseismic deformation following the Tarapaca earthquake on the megathrust interface and nodal planes of its M 6.7 foreshock. These static stress calculations show that the Tarapaca earthquake may have an indirect influence on the Iquique earthquake, via loading of the M 6.7 preshock positively. We demonstrate the feasibility of using deep intraslab earthquakes to constrain subduction zone rheology. Continuing geodetic observation following the 2014 Iquique earthquake may further validate the rheological parameters obtained here.

  15. Stress drops and radiated energies of aftershocks of the 1994 Northridge, California, earthquake


    Mori, Jim; Abercrombie, Rachel E.; Kanamori, Hiroo


    We study stress levels and radiated energy to infer the rupture characteristics and scaling relationships of aftershocks and other southern California earthquakes. We use empirical Green functions to obtain source time functions for 47 of the larger (M ≥ 4.0) aftershocks of the 1994 Northridge, California earthquake (M6.7). We estimate static and dynamic stress drops from the source time functions and compare them to well-calibrated estimates of the radiated energy. Our measurements of radiat...

  16. Well-being and perceived quality of life in elderly people displaced after the earthquake in L'Aquila, Italy. (United States)

    Giuliani, Anna Rita; Mattei, Antonella; Santilli, Flavio; Clori, Giovanna; Scatigna, Maria; Fabiani, Leila


    On 6 April 2009, the city of L'Aquila was hit by a violent earthquake that destroyed almost all of its medieval centre, and the surviving inhabitants were evacuated and relocated in temporary quarters or undamaged homes. The aim of this study was to investigate the perceived quality of life of the elderly population 3 years after the earthquake in relation to the social and logistic issues of new housing. The study was carried out between October 2011 and March 2012, and involved 571 subjects aged over 65 years living in the municipality of L'Aquila. The interviews took place in the surgeries of general practitioners and the city's Department of Prevention and Vaccination in the anti-influenza immunisation period. The instrument used was a 36-item questionnaire with closed, multiple choice answers divided into the following sections: demographics, everyday activities, health and perceived health, and the quality of life in the city. The results show that, 3 years after the earthquake, the elderly population living in the new towns and temporary housing of L'Aquila have a worse perception of their quality of life than the others. They feel a certain social isolation and wish to live elsewhere. Governments faced with the problems arising from a natural calamity should take into account all of the elements making up a good quality of life and, before making choices whose impact cannot be changed, consider both their immediate and long-term social consequences.

  17. Effects of sea water on elongated duration of ground motion as well as variation in its amplitude for offshore earthquakes (United States)

    Todoriki, Masaru; Furumura, Takashi; Maeda, Takuto


    We investigated the effects of sea water on the propagation of seismic waves using a 3-D finite-difference-method simulation of seismic wave propagation following offshore earthquakes. When using a 1-D layered structure, the simulation results showed strong S- to P-wave conversion at the sea bottom; accordingly, S-wave energy was dramatically decreased by the sea water layer. This sea water de-amplification effect had strong frequency dependence, therefore resembling a low-pass filter in which the cut-off frequency and damping coefficients were defined by the thickness of the sea water layer. The sea water also acted to elongate the duration of Rayleigh wave packet. The importance of the sea water layer in modelling offshore earthquakes was further demonstrated by a simulation using a realistic 3-D velocity structure model with and without sea water for a shallow (h = 14 km) outer-rise Nankai Trough event, the 2004 SE Off Kii Peninsula earthquake (Mw = 7.2). Synthetic seismograms generated by the model when sea water was included were in accordance with observed seismograms for long-term longer period motions, particularly those in the shape of Rayleigh waves.

  18. Evaluating the role of large earthquakes on aquifer dynamics using data fusion and knowledge discovery techniques (United States)

    Friedel, Michael; Cox, Simon; Williams, Charles; Holden, Caroline


    Artificial adaptive systems are evaluated for their usefulness in modeling earthquake hydrology of the Canterbury region, NZ. For example, an unsupervised machine-learning technique, self-organizing map, is used to fuse about 200 disparate and sparse data variables (such as, well pressure response, ground acceleration, intensity, shaking, stress and strain; aquifer and well characteristics) associated with the M7.1 Darfield earthquake in 2010 and the M6.3 Christchurch earthquake in 2011. The strength of correlations, determined using cross-component plots, varied between earthquakes with pressure changes more strongly related to dynamic- than static stress-related variables during the M7.1 earthquake, and vice versa during the M6.3. The method highlights the importance of data distribution and that driving mechanisms of earthquake-induced pressure change in the aquifers are not straight forward to interpret. In many cases, data mining revealed that confusion and reduction in correlations are associated with multiple trends in the same plot: one for confined and one for unconfined earthquake response. The autocontractive map and minimum spanning tree techniques are used for grouping variables of similar influence on earthquake hydrology. K-means clustering of neural information identified 5 primary regions influenced by the two earthquakes. The application of genetic doping to a genetic algorithm is used for identifying optimal subsets of variables in formulating predictions of well pressures. Predictions of well pressure changes are compared and contrasted using machine-learning network and symbolic regression models with prediction uncertainty quantified using a leave-one-out cross-validation strategy. These preliminary results provide impetus for subsequent analysis with information from another 100 earthquakes that occurred across the South Island.

  19. Variations of terrestrial geomagnetic activity correlated to M6+ global seismic activity (United States)

    Cataldi, Gabriele; Cataldi, Daniele; Straser, Valentino


    From the surface of the Sun, as a result of a solar flare, are expelled a coronal mass (CME or Coronal Mass Ejection) that can be observed from the Earth through a coronagraph in white light. This ejected material can be compared to an electrically charged cloud (plasma) mainly composed of electrons, protons and other small quantities of heavier elements such as helium, oxygen and iron that run radially from the Sun along the lines of the solar magnetic field and pushing into interplanetary space. Sometimes the CME able to reach the Earth causing major disruptions of its magnetosphere: mashed in the region illuminated by the Sun and expanding in the region not illuminated. This interaction creates extensive disruption of the Earth's geomagnetic field that can be detected by a radio receiver tuned to the ELF band (Extreme Low Frequency 0-30 Hz). The Radio Emissions Project (scientific research project founded in February 2009 by Gabriele Cataldi and Daniele Cataldi), analyzing the change in the Earth's geomagnetic field through an induction magnetometer tuned between 0.001 and 5 Hz (bandwidth in which possible to observe the geomagnetic pulsations) was able to detect the existence of a close relationship between this geomagnetic perturbations and the global seismic activity M6+. During the arrival of the CME on Earth, in the Earth's geomagnetic field are generated sudden and intensive emissions that have a bandwidth including between 0 and 15 Hz, an average duration of 2-8 hours, that preceding of 0-12 hours M6+ earthquakes. Between 1 January 2012 and 31 December 2012, all M6+ earthquakes recorded on a global scale were preceded by this type of signals which, due to their characteristics, have been called "Seismic Geomagnetic Precursors" (S.G.P.). The main feature of Seismic Geomagnetic Precursors is represented by the close relationship that they have with the solar activity. In fact, because the S.G.P. are geomagnetic emissions, their temporal modulation depends

  20. `DSF' theory on mechanism of gushing anomaly in oil and water wells before an earthquake. I. Observation of gushing and causative hypothesis (United States)

    Liu-qiao, Wang; Shan-yin, Li


    The gushing anomaly that occurs prior to an earthquake, a short-term abnormal phenomenon of common occurrence, is simply described here. It has been observed by an automatic recording float gauge that has continually operated for nine years at Wei-jiaquan No. 5 well in Miquan County of Xinjiang Province (XMW-5 well). During this period, four abnormal events have been recorded which show that the water level curve of the anomaly has a characteristic shape. By analysing the characteristic shape of the water level curve, we believed that an unknown rapidly varying stress field operated prior to an earthquake, thereby compressing the aquifer bed to cause an elastic deformation seepage-flow effect. Thus, a two-dimensional model of a radially unsteady seepage flow within a single aquifer bed, under variable tectonic stress, and with a rectangular pulse, was proposed. The abnormal water-level curve was then quantitatively synthesized on the basis of the above theory. The causative hypothesis (DSF) is based on the elastic deformation seepage-flow (DSF) theory.

  1. Study of earthquakes using a borehole seismic network at Koyna, India (United States)

    Gupta, Harsh; Satyanarayana, Hari VS; Shashidhar, Dodla; Mallika, Kothamasu; Ranjan Mahato, Chitta; Shankar Maity, Bhavani


    Koyna, located near the west coast of India, is a classical site of artificial water reservoir triggered earthquakes. Triggered earthquakes started soon after the impoundment of the Koyna Dam in 1962. The activity has continued till now including the largest triggered earthquake of M 6.3 in 1967; 22 earthquakes of M ≥ 5 and several thousands smaller earthquakes. The latest significant earthquake of ML 3.7 occurred on 24th November 2016. In spite of having a network of 23 broad band 3-component seismic stations in the near vicinity of the Koyna earthquake zone, locations of earthquakes had errors of 1 km. The main reason was the presence of 1 km thick very heterogeneous Deccan Traps cover that introduced noise and locations could not be improved. To improve the accuracy of location of earthquakes, a unique network of eight borehole seismic stations surrounding the seismicity was designed. Six of these have been installed at depths varying from 981 m to 1522 m during 2015 and 2016, well below the Deccan Traps cover. During 2016 a total of 2100 earthquakes were located. There has been a significant improvement in the location of earthquakes and the absolute errors of location have come down to ± 300 m. All earthquakes of ML ≥ 0.5 are now located, compared to ML ≥1.0 earlier. Based on seismicity and logistics, a block of 2 km x 2 km area has been chosen for the 3 km deep pilot borehole. The installation of the borehole seismic network has further elucidated the correspondence between rate of water loading/unloading the reservoir and triggered seismicity.

  2. Slip Distribution of Two Recent Large Earthquakes in the Guerrero Segment of the Mexican Subduction Zone, and Their Relation to Previous Earthquakes, Silent Slip Events and Seismic Gaps (United States)

    Hjorleifsdottir, V.; Ji, C.; Iglesias, A.; Cruz-Atienza, V. M.; Singh, S. K.


    In 2012 and 2014 mega-thrust earthquakes occurred approximately 300 km apart, in the state of Guerrero, Mexico. The westernmost half of the segment between them has not had a large earthquake in at least 100 years and most of the easternmost half last broke in 1957. However, down dip of both earthquakes, silent slip events have been reported, as well as in the gap between them (Kostoglodov et al 2003, Graham 2014). There are indications that the westernmost half has different frictional properties than the areas surrounds it. However, the two events at the edges of the zone also seem to behave in different manners, indicating a broad range of frictional properties in this area, with changes occurring over short distances. The 2012/03/20, M7.5 earthquake occurred near the Guerrero-Oaxaca border, between the towns of Ometepec (Gro.) and Pinotepa Nacional (Oax.). This earthquake is noteworthy for breaking the same asperities as two previously recorded earthquakes, the M7.2 1937 and M6.9 1982(a) earthquakes, in very large "repeating earthquakes". Furthermore, the density of repeating smaller events is larger in this zone than in other parts of the subduction zone (Dominguez et al, submitted) and this earthquake has had very many aftershocks for its size (UNAM Seis. group, 2013). The 2012 event may have broken two asperities (UNAM Seis. group, 2013). How the two asperities relate to the previous relatively smaller "large events", to the repeating earthquakes, the high number of aftershocks and to the slow slip event is not clear. The 2014/04/18 M 7.2 earthquake broke a patch on the edge of the Guerrero gap, that previously broke in the 1979 M7.4 earthquake as well as the 1943 M 7.4 earthquake. This earthquake, despite being smaller, had a much larger duration, few aftershocks and clearly ruptured two separate patches (UNAM Seis. group 2015). In this work we estimate the slip distributions for the 2012 and 2014 earthquakes, by combining the data used separately in

  3. Poroelastic properties of the Arbuckle Group in Oklahoma derived from well fluid level response to the 3 September 2016 Mw 5.8 Pawnee and 7 November 2016 Mw 5.0 Cushing earthquakes (United States)

    Kroll, Kayla A.; Cochran, Elizabeth S.; Murray, Kyle E.


    The Arbuckle Group (Arbuckle) is a basal sedimentary unit that is the primary target for saltwater disposal in Oklahoma. Thus, the reservoir characteristics of the Arbuckle, including how the poroelastic properties change laterally and over time are of significant interest. We report observations of fluid level changes in two monitoring wells in response to the 3 September 2016 Mw 5.8 Pawnee and the 7 November 2016 Mw 5.0 Cushing earthquakes. We investigate the relationship between static strain resulting from these events and the fluid level changes observed in the wells. We model the fluid level response by estimating static strains from a set of earthquake source parameters and spatiotemporal poroelastic properties of the Arbuckle in the neighborhood of the monitoring wells. Results suggest that both the direction of the observed fluid level step and the amplitude can be predicted from the computed volumetric strain change and a reasonable set of poroelastic parameters. Modeling results indicate that poroelastic parameters differ at the time of the Pawnee and Cushing earthquakes, with a moderately higher Skempton’s coefficient required to fit the response to the Cushing earthquake. This may indicate that dynamic shaking resulted in physical alteration of the Arbuckle at distances up to ∼50  km from the Pawnee earthquake.

  4. Operational earthquake forecasting can enhance earthquake preparedness (United States)

    Jordan, T.H.; Marzocchi, W.; Michael, A.J.; Gerstenberger, M.C.


    We cannot yet predict large earthquakes in the short term with much reliability and skill, but the strong clustering exhibited in seismic sequences tells us that earthquake probabilities are not constant in time; they generally rise and fall over periods of days to years in correlation with nearby seismic activity. Operational earthquake forecasting (OEF) is the dissemination of authoritative information about these time‐dependent probabilities to help communities prepare for potentially destructive earthquakes. The goal of OEF is to inform the decisions that people and organizations must continually make to mitigate seismic risk and prepare for potentially destructive earthquakes on time scales from days to decades. To fulfill this role, OEF must provide a complete description of the seismic hazard—ground‐motion exceedance probabilities as well as short‐term rupture probabilities—in concert with the long‐term forecasts of probabilistic seismic‐hazard analysis (PSHA).

  5. Research on the Accurate Location of the 2007 Ms 6. 4 Ning'er, Yunnan Earthquake

    Institute of Scientific and Technical Information of China (English)

    Lu Xian; Zhou Longquan


    Five mobile digital seismic stations were set up by the Earthquake Administration of Yunnan Province near the epicenter of the main shock after the Ning'er M6. 4 earthquake on June 3, 2007. In this paper, the aftershock sequence of the Ning'er M6. 4 earthquake is relocated by using the double difference earthquake location method. The data is from the 5 mobile digital seismic stations and the permanent Simao seismic station. The results show that the length of the aftershock sequence is 40kin and the width is 30km, concentrated obviously at the lateral displacement area between the Pu'er fault and the NNE-trending faults, with the majority occurring on the Pu'er fault around the main shock. The depths of aftershocks are from 2kin to 12km, and the predominant distribution is in the depth of 8 ~ 10km. The mean depth is 7. 9kin. The seismic fault dips to the northwest revealed from the profile parallel to this aftershock sequence, which is identical to the dip of the secondary fault of the NE-trending Menglian-Mojiang fault in the earthquake area. There are more earthquakes concentrated in the northwest segment than in the southeast segment, which is perhaps related to the underground medium and faults. The depth profile of the earthquake sequence shows that the relocated earthquakes are mainly located near the Pu'er fault and the seismic faults dip to the southwest, consistent with the dip of the west branch of the Pu'er fault. In all, the fault strike revealed by earthquake relocations matches well with the strike in the focal mechanism solutions. The main shock is in the top of the aftershock sequence and the aftershocks are symmetrically distributed, showing that faulting was complete in both the NE and SW directions.

  6. Encyclopedia of earthquake engineering

    CERN Document Server

    Kougioumtzoglou, Ioannis; Patelli, Edoardo; Au, Siu-Kui


    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...

  7. The physical nature of thermal anomalies observed before strong earthquakes (United States)

    Pulinets, S. A.; Ouzounov, D.; Karelin, A. V.; Boyarchuk, K. A.; Pokhmelnykh, L. A.

    The paper examines the effect of air ionization on the thermal balance of the boundary layer of atmosphere. In seismically active areas the increased radon emanation from active faults and cracks before earthquakes is the primary source of air ionization. The problem is analyzed both on microscopic and macroscopic levels and in both cases the significant changes of the air relative humidity and air temperature are obtained. This happens due to the water molecules attachment to the newly formed ions (or in other words, condensation) which leads to the excretion of the latent heat. Obtained results permit us to explain the changes of the surface temperature and the surface latent heat flux increase before earthquakes observed by remote sensing satellites, as well as ground based measurements of the air temperature and relative humidity variations before the Colima earthquake (M7.6) of 2003 in Mexico, Hector Mine earthquake (M7.1) of 1999 in USA and Parkfield earthquake (M6) of 2004 in USA. These findings are also supported by the results of active experiments where the installation of artificial ionization of atmosphere is used.

  8. Classification of M~7 earthquakes in Tokyo Metropolitan area since 1885 - The 1921 Ibaraki-ken Nambu and 1922 Uraga channel earthquakes (United States)

    Ishibe, T.; Satake, K.; Shimazaki, K.; Murotani, S.; Nishiyama, A.


    S-P times, focal mechanism solutions from initial motion, and seismic intensity distribution show that the 1921 Ibaraki-ken Nambu earthquake (M 7.0) and the 1922 Uraga channel earthquake (M 6.8) both occurred within the subducting Philippine Sea plate beneath the Tokyo Metropolitan area. The Tokyo Metropolitan area is situated in a tectonically complex region; The Philippine Sea plate (PHS) subducts from south, while the Pacific plate (PAC) subducts from east below PHS. As a result, various types of earthquakes occur in this region. They are classified into: shallow crustal earthquakes, intraplate (slab) earthquakes within PHS, within PAC, and interplate earthquakes between continental plate and PHS, and between PHS and PAC. The probability of the large earthquakes with magnitude (M)~7 is high; Earthquake Research Committee calculated the probability of occurrence during the next 30 years as 70 %, based on the fact that five M~7 earthquakes (the 1894 Meiji Tokyo, 1895 and 1921 Ibaraki-ken Nambu, 1922 Uraga Channel, and 1987 Chiba-ken Toho-oki earthquakes) occurred since 1885. However, types of these earthquakes except for the 1987 earthquake are not well known due to low quality of data. It is important to classify these earthquakes into above-described intraplate or interplate earthquakes. The Ibaraki-ken Nambu earthquake occurred on 8 December, 1921 and caused damage such as fissures on road, tumble of gravestones especially in the northwestern Chiba and southwestern Ibaraki prefectures. The focal depth was estimated to be around 55 km using S-P times of old seismograms or JMA reports, suggesting that this earthquake was probably a slab earthquake within PHS. Seismic intensity distribution supports this result; seismic intensity anomalies characterizing the PAC slab earthquakes are not recognized. Furthermore, initial motion focal mechanisms using HASH algorithm (Hardebeck and Shearer, 2002) are strike-slip types, even if the uncertainty of hypocenter locations

  9. Seismomagnetic models for earthquakes in the eastern part of Izu Peninsula, Central Japan

    Directory of Open Access Journals (Sweden)

    Y. Ishikawa


    Full Text Available Seismomagnetic changes accompanied by four damaging earthquakes are explained by the piezomagnetic effect observed in the eastern part of Izu Peninsula, Central Japan. Most of the data were obtained by repeat surveys. Although these data suffered electric railway noise, significant magnetic changes were detected at points close to earthquake faults. Coseismic changes can be well interpreted by piezomagnetic models in the case of the 1978 Near Izu-Oshima (M 7.0 and the 1980 East Off Izu Peninsula (M 6.7 earthquakes. A large total intensity change up to 5 nT was observed at a survey point almost above the epicenter of the 1976 Kawazu (M 5.4 earthquake. This change is not explained by a single fault model; a 2-segment fault is suggested. Remarkable precursory and coseismic changes in the total force intensity were observed at KWZ station along with the 1978 Higashi-Izu (M 4.9 earthquake. KWZ station is located very close to a buried subsidiary fault of the M 7.0 Near Izu-Oshima earthquake, which moved aseismically at the time of the M 7.0 quake. The precursory magnetic change to the M 4.9 quake is ascribed to aseismic faulting of this buried fault, while the coseismic rebound to enlargement of the slipping surface at the time of M 4.9 quake. This implies that we observed the formation process of the earthquake nucleation zone via the magnetic field.

  10. Nowcasting Earthquakes (United States)

    Rundle, J. B.; Donnellan, A.; Grant Ludwig, L.; Turcotte, D. L.; Luginbuhl, M.; Gail, G.


    Nowcasting is a term originating from economics and finance. It refers to the process of determining the uncertain state of the economy or markets at the current time by indirect means. We apply this idea to seismically active regions, where the goal is to determine the current state of the fault system, and its current level of progress through the earthquake cycle. In our implementation of this idea, we use the global catalog of earthquakes, using "small" earthquakes to determine the level of hazard from "large" earthquakes in the region. Our method does not involve any model other than the idea of an earthquake cycle. Rather, we define a specific region and a specific large earthquake magnitude of interest, ensuring that we have enough data to span at least 20 or more large earthquake cycles in the region. We then compute the earthquake potential score (EPS) which is defined as the cumulative probability distribution P(nearthquakes in the region. From the count of small earthquakes since the last large earthquake, we determine the value of EPS = P(nearthquake cycle in the defined region at the current time.

  11. Earthquake Facts (United States)

    Jump to Navigation Earthquake Facts The largest recorded earthquake in the United States was a magnitude 9.2 that struck Prince William Sound, ... we know, there is no such thing as "earthquake weather" . Statistically, there is an equal distribution of ...

  12. Nowcasting earthquakes (United States)

    Rundle, J. B.; Turcotte, D. L.; Donnellan, A.; Grant Ludwig, L.; Luginbuhl, M.; Gong, G.


    Nowcasting is a term originating from economics and finance. It refers to the process of determining the uncertain state of the economy or markets at the current time by indirect means. We apply this idea to seismically active regions, where the goal is to determine the current state of the fault system and its current level of progress through the earthquake cycle. In our implementation of this idea, we use the global catalog of earthquakes, using "small" earthquakes to determine the level of hazard from "large" earthquakes in the region. Our method does not involve any model other than the idea of an earthquake cycle. Rather, we define a specific region and a specific large earthquake magnitude of interest, ensuring that we have enough data to span at least 20 or more large earthquake cycles in the region. We then compute the earthquake potential score (EPS) which is defined as the cumulative probability distribution P(n < n(t)) for the current count n(t) for the small earthquakes in the region. From the count of small earthquakes since the last large earthquake, we determine the value of EPS = P(n < n(t)). EPS is therefore the current level of hazard and assigns a number between 0% and 100% to every region so defined, thus providing a unique measure. Physically, the EPS corresponds to an estimate of the level of progress through the earthquake cycle in the defined region at the current time.

  13. Statistical Monitoring of the Seismic Activities before and after the Kumamoto Earthquakes (United States)

    Ogata, Y.; Kumazawa, T.; Tsuruoka, H.


    It is expected that the probability gain of a large earthquake in an aftershock region or its vicinity can be elevated by the presence of the relative quiescence in seismicity sequence (Ogata 2001). We first analyzed the seismicity in the Kumamoto region since 2010 before the occurrence of the M6.5 first foreshock. Although the ETAS model well fits the seismicity in the most subregions of the Kumamoto District, anomalous swarm activities are observed in the subregions to the north of the bending part of the focal faults on which the foreshocks of M6.5, M6.4 and the main shock M7.3 successively occurred. These anomalous swarm activities are characterized by the nonstationary ETAS model. We then applied the ETAS model to the aftershock sequence of M6.5 event or of a few other major earthquakes which precedes the Kumamoto main shock, and revealed that there was relative quiescence. It is also seen that M6.5 aftershocks migrated deeper and closer to the M7.3 hypocenter. We further applied the ETAS model and non-stationary ETAS model (Kumazawa and Ogata 2013) and also model of the b-value change estimate, to the sequence throughout the M6.5 foreshock sequence and M7.3 aftershocks. Moreover, we examined regionally different aftershock activities between the main and off fault zones. In particular, the aftershock productivity parameter K0(t) is high during the foreshocks, and decreased after the M7.3 main shock, whereas the background seismicity rate μ(t) stays constant through the entire period. The b-values show stepwise increasing changes at major events of the M6.5, M6.4, and M7.3.

  14. The Need for More Earthquake Science in Southeast Asia (United States)

    Sieh, K.


    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.

  15. The 2016 Central Italy Earthquake: an Overview (United States)

    Amato, A.


    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

  16. 荣昌华江井水温震后特异变化分析%Specific water temperature changes after earthquake presented by Huajiang well in Rongchang County

    Institute of Scientific and Technical Information of China (English)

    陈敏; 董蕾; 李光科; 马伟; 张涛; 巩浩波


    重庆市荣昌华江井水温在2008年5月汶川M 8.0地震、2010年4月玉树M 7.1地震、2010年9月荣昌M 4.7地震和2011年3月日本东海M 9.0地震时均有同震上升型响应与震后持续高值异常变化。其中在汶川地震与荣昌地震震后6—72小时,记录到叠加在高值上的群集型正脉冲特异变化。变化持续53—109天,最大脉冲幅度0.038℃,为正常日变化幅度0.0055℃的7倍。初步研究结果表明,这种特殊的水温微动态现象,是在特定地质条件下,区域性强震与当地中等地震活动激发深层气体释放并侵入观测井引起。%Both ascendant rcoseismic responses and high value changes after main-shock are recorded by the specific water temperature changes of Huajiang well in Rongchang, Chongqing during WenchuanMS8.0 earthquake in May, 2008, YushuMS7.1 earthquake in April, 2010, Rongchang MS4.7 earthquake in Sep., 2010 and JapanMS9.0 earthquake in March, 2011. Among them, after 6 to 72 hours of Wenchuan earthquake and Rangchang earthquake, speciifc changes of cluster type positive pulse stacked on high value were also recorded. The duration of changes is 53 to 109 days, and maximal amplitude of pulse is 0.038℃, about 7 times of the normal amplitude, 0.000 55℃, of daily changes. The preliminary results indicate that these new micro dynamic of water temperature is probably caused by releasing of deep gas stimulated by seismic activity and invading into the observation well under certain geological conditions.

  17. Earthquake forecast enrichment scores

    Directory of Open Access Journals (Sweden)

    Christine Smyth


    Full Text Available The Collaboratory for the Study of Earthquake Predictability (CSEP is a global project aimed at testing earthquake forecast models in a fair environment. Various metrics are currently used to evaluate the submitted forecasts. However, the CSEP still lacks easily understandable metrics with which to rank the universal performance of the forecast models. In this research, we modify a well-known and respected metric from another statistical field, bioinformatics, to make it suitable for evaluating earthquake forecasts, such as those submitted to the CSEP initiative. The metric, originally called a gene-set enrichment score, is based on a Kolmogorov-Smirnov statistic. Our modified metric assesses if, over a certain time period, the forecast values at locations where earthquakes have occurred are significantly increased compared to the values for all locations where earthquakes did not occur. Permutation testing allows for a significance value to be placed upon the score. Unlike the metrics currently employed by the CSEP, the score places no assumption on the distribution of earthquake occurrence nor requires an arbitrary reference forecast. In this research, we apply the modified metric to simulated data and real forecast data to show it is a powerful and robust technique, capable of ranking competing earthquake forecasts.

  18. Development of volcano monitoring technique using repeating earthquakes observed by the Volcano Observation Network of NIED (United States)

    Kohno, Y.; Ueda, H.; Kimura, H.; Nagai, M.; Miyagi, Y.; Fujita, E.; Kozono, T.; Tanada, T.


    After the Grate East Japan Earthquake (M9.0) on March 11, 2011, the M6.4 earthquake occurred beneath Mt. Fuji on March 15, 2011. Although the hypocenter seemed to be very close to an assumed magma chamber of Fuji volcano, no anomalies in volcanic activity have been observed until August 2012. As an example, after the M6.1 earthquake occurred in 1998 at southwest of Iwate volcano, a change of seismic velocity structure (e.g. Nishimura et al., 2000) was observed as well as active seismicity and crustal deformation. It had affected waveforms of repeating earthquakes occurring at a plate subduction zone, that is, the waveform similarities were reduced just after the earthquake due to upwelling of magma. In this study, first we analyzed for Mt. Fuji where such changes are expected by the occurrence of the earthquake to try to develop a tool for monitoring active volcanoes using the Volcano Observation network (V-net) data. We used seismic waveform data of repeating earthquakes observed by short period seismometers of V-net and the High Sensitivity Seismograph Network Japan (Hi-net) stations near Fuji volcano after 2007. The seismic data were recorded with a sampling rate of 100 Hz, and we applied 4-8 Hz band pass filter to reduce noise. The repeating earthquakes occurred at the plate subduction zone and their catalog is compiled by Hi-net data (Kimura et al., 2006). We extracted repeating earthquake groups that include earthquakes before and after the M6.4 earthquake on March 15, 2011. A waveform of the first event of the group and waveforms of the other events are compared and calculated cross-correlation coefficients. We adjusted P wave arrivals of each event and calculate the coefficients and lag times of the latter part of the seismic waves with the time window of 1.25 s. We searched the best fit maximizing the cross-correlation coefficients with 0.1 s shift time at each time window. As a result we found three remarkable points at this time. [1] Comparing lag times

  19. April 25, 2015, Gorkha Earthquake, Nepal and Sequence of Aftershocks: Key Lessons (United States)

    Guragain, R.; Dixit, A. M.; Shrestha, S. N.


    The Gorkha Earthquake of M7.8 hit Nepal on April 25, 2015 at 11:56 am local time. The epicenter of this earthquake was Barpak, Gorkha, 80 km northwest of Kathmandu Valley. The main shock was followed by hundreds of aftershocks including M6.6 and M6.7 within 48 hours and M7.3 on May 12, 2015. According to the Government of Nepal, a total of 8,686 people lost their lives, 16,808 people injured, over 500,000 buildings completely collapsed and more than 250,000 building partially damaged. The National Society for Earthquake Technology - Nepal (NSET), a not-for-profit civil society organization that has been focused on earthquake risk reduction in Nepal for past 21 years, conducted various activities to support people and the government in responding to the earthquake disaster. The activities included: i) assisting people and critical facility institutions to conduct rapid visual building damage assessment including the training; ii) information campaign to provide proper information regarding earthquake safety; iii) support rescue organizations on search and rescue operations; and iv) provide technical support to common people on repair, retrofit of damaged houses. NSET is also involved in carrying out studies related to earthquake damage, geotechnical problems, and causes of building damages. Additionally, NSET has done post-earthquake detail damage assessment of buildings throughout the affected areas. Prior to the earthquake, NSET has been working with several institutions to improve seismic performance of school buildings, private residential houses, and other critical structures. Such activities implemented during the past decade have shown the effectiveness of risk reduction. Retrofitted school buildings performed very well during the earthquake. Preparedness activities implemented at community levels have helped communities to respond immediately and save lives. Higher level of earthquake awareness achieved including safe behavior, better understanding of

  20. Listening to Earthquakes with Infrasound (United States)

    Mucek, A. E.; Langston, C. A.


    A tripartite infrasound array was installed to listen to earthquakes occurring along the Guy-Greenbrier fault in Arkansas. The active earthquake swarm is believed to be caused by deep waste water injections and will allow us to explain the mechanisms causing earthquake "booms" that have been heard during an earthquake. The array has an aperture of 50 meters and is installed next to the X301 seismograph station run by the Center for Earthquake Research and Information (CERI). This arrangement allows simultaneous recording of seismic and acoustic changes from the arrival of an earthquake. Other acoustic and seismic sources that have been found include thunder from thunderstorms, gunshots, quarry explosions and hydraulic fracturing activity from the local gas wells. The duration of the experiment is from the last week of June to the last week of September 2011. During the first month and a half, seven local earthquakes were recorded, along with numerous occurrences of the other infrasound sources. Phase arrival times of the recorded waves allow us to estimate wave slowness and azimuth of infrasound events. Using these two properties, we can determine whether earthquake "booms" occur at a site from the arrival of the P-wave or whether the earthquake "booms" occur elsewhere and travel through the atmosphere. Preliminary results show that the infrasound correlates well to the ground motion during an earthquake for frequencies below 15 Hertz.

  1. Liquefaction-induced lateral spreading in Oceano, California, during the 2003 San Simeon Earthquake (United States)

    Holzer, Thomas L.; Noce, Thomas E.; Bennett, Michael J.; Di Alessandro, Carola; Boatwright, John; Tinsley, John C.; Sell, Russell W.; Rosenberg, Lewis I.


    The December 22, 2003, San Simeon, California, (M6.5) earthquake caused damage to houses, road surfaces, and underground utilities in Oceano, California. The community of Oceano is approximately 50 miles (80 km) from the earthquake epicenter. Damage at this distance from a M6.5 earthquake is unusual. To understand the causes of this damage, the U.S. Geological Survey conducted extensive subsurface exploration and monitoring of aftershocks in the months after the earthquake. The investigation included 37 seismic cone penetration tests, 5 soil borings, and aftershock monitoring from January 28 to March 7, 2004. The USGS investigation identified two earthquake hazards in Oceano that explain the San Simeon earthquake damage?site amplification and liquefaction. Site amplification is a phenomenon observed in many earthquakes where the strength of the shaking increases abnormally in areas where the seismic-wave velocity of shallow geologic layers is low. As a result, earthquake shaking is felt more strongly than in surrounding areas without similar geologic conditions. Site amplification in Oceano is indicated by the physical properties of the geologic layers beneath Oceano and was confirmed by monitoring aftershocks. Liquefaction, which is also commonly observed during earthquakes, is a phenomenon where saturated sands lose their strength during an earthquake and become fluid-like and mobile. As a result, the ground may undergo large permanent displacements that can damage underground utilities and well-built surface structures. The type of displacement of major concern associated with liquefaction is lateral spreading because it involves displacement of large blocks of ground down gentle slopes or towards stream channels. The USGS investigation indicates that the shallow geologic units beneath Oceano are very susceptible to liquefaction. They include young sand dunes and clean sandy artificial fill that was used to bury and convert marshes into developable lots. Most of

  2. Preseismic Changes of Water Temperature in the Yushu Well, Western China (United States)

    Sun, Xiaolong; Xiang, Yang; Shi, Zheming; Wang, Bo


    We observed abnormal changes of the water temperature in Yushu (YSWT) well, China, most of which were followed by earthquakes. This study statistically analyzes the correlation between the magnitude and duration of the anomalies in YSWT and earthquakes in the Tibetan block and its margins. The effectiveness of using observed YSWT data to predict earthquakes was quantitatively examined by the Molchan error diagram method. The results show that (1) the YSWT underwent several abnormal changes marked by "V"-shaped patterns, which might be related to several earthquakes that occurred in the Tibetan block and its margins. The extent and duration of the abnormal changes in the YSWT were linearly related to the magnitude of the earthquake; i.e., the higher the magnitude, the greater the change in the YSWT, and the shorter the duration. (2) Abnormal changes in the YSWT are somewhat predictive of earthquakes with magnitudes ≥5.5 (≥M5.5) within 800 km of the Yushu well and ≥M6.5 earthquakes in the Tibetan block and its margins. The prediction has a probability gain of approximately 2, and the most likely time period for an earthquake to occur is within approximately 3 months after the occurrence of an YSWT anomaly. Most of the anomalies in YSWT appeared before earthquakes in the thrust of block margins. Notably the larger strains from the earthquake did not produce any response. We speculate that the preseismic responses reflect the regional tectonics, such as the motion of the Indian plate, straining sub-blocks of the Tibetan block.

  3. The Elmore Ranch and Superstition Hills earthquakes of 24 November 1987: Introduction to the special issue


    Hanks, Thomas C.; Allen, Clarence R.


    On 24 November 1987, two significant earthquakes occurred along the southern San Jacinto fault zone and related structural elements in southern California, not far from the International Border. These two events, the Elmore Ranch earthquake (M = 6.2 at 0154 GMT) and the Superstition Hills earthquake (M = 6.6 at 1315 GMT, both moment magnitudes from Sipkin, 1989), and their aftershocks have yielded a rich harvest of geological, seismological, and engineering data pertinent to the cause and ...

  4. Study of the 11th July, 1915, Portuguese offshore earthquake, in the Atlantic from contemporary seismograms and bulletins (United States)

    Batllo-Ortiz, J.; Custodio, S.; Macia, R.; Teves-Costa, P.


    The seismicity rate in the contact of the Nubian and Euro-Asiatic plates along the Azores-Gibraltar region can be considered moderate. Nevertheless, large earthquakes do occur, as is well known from historical records. The sensibility of seismographic networks to earthquakes with oceanic origin has been extremely low until recent times. Oceanic M5 earthquakes have not been consistently recorded up to the second third of the XX century, precluding a proper knowledge of seismicity rates and other parameters of interest for earthquake hazard. Nevertheless, information for some events does exist, most of which remains to be properly studied. In this paper we analyze historical data for the 11th July, 1915 earthquake, which occurred offshore and was felt over the whole mainland Portugal. This event is one of the largest occurred during the instrumental period in the region of diffuse seismicity around the Gorringe bank. However it has been little studied, probably because it did not cause serious damage. The 11th July, 1915 earthquake is of great interest due to its size, estimated on the order of M6, and to its unique location with respect to the regions of large earthquakes in the Atlantic. In this paper, we present source parameters for this earthquake based on the analysis of the available contemporary seismograms and related documents. After throughout collection and selection, 23 seismograms obtained at 11 different European stations were digitized and processed. The event was relocated and its magnitude recalculated. Its focal mechanism has also been studied through waveform modeling and first motion polarity. We present the results of this analysis, compare the source of the 1915 earthquake with that of present earthquakes in the same region, and interpret the new results in light of the regional seismicity and seismo-tectonics.

  5. Coulomb stress evolution along Xianshuihe-Xiaojiang Fault System since 1713 and its interaction with Wenchuan earthquake, May 12, 2008 (United States)

    Shan, Bin; Xiong, Xiong; Wang, Rongjiang; Zheng, Yong; Yang, Song


    The curved left-lateral strike-slip Xianshuihe-Xiaojiang Fault System (XXFS) in southwestern China extends at least 1400 km in the eastern margin of the Tibetan Plateau. Fieldworks confirm that the XXFS is one of the longest and most seismically active faults in China. The strain released by the slip motion on the XXFS is related to the convergence between the Indian and Eurasian plates. The entire fault system has experienced at least 35 earthquakes of M>6 in the recent 300 years and almost all segments of the system have been the locus of major historical earthquakes. Since the XXFS region is heavily populated (over 50 million people), understanding the migration of the large earthquakes in space and time is of crucial importance for the seismic hazard assessment in this region. We analyze a sequence of 25 earthquakes (M⩾6.5) that occurred along the XXFS since 1713, and investigate their influence on the 2008 Mw7.9 Wenchuan earthquake occurred on the adjacent Longmenshan fault. In our analysis, the relevant parameters for the earth crust are constrained by seismic studies. The locations and geometries of the earthquake faults as well as the rupture distributions are taken from field observations and seismological studies. Results from the Coulomb failure stress modeling indicate significant interactions among the earthquakes. After the 1713 earthquake, 19 out of 24 earthquakes occurred in the positive stress zone of the preceding earthquakes. The other 5 earthquakes located in the area without significant stress changes induced by the preceding events. In particular, we can identify 4 visible earthquake gaps with increasing seismic hazard along the XXFS, consistent with the findings from the paleo-seismological studies. The seismic activity and tectonic motion on the XXFS reduced the Coulomb stress accumulation at the hypocenter of 2008 Mw7.9 Wenchuan earthquake, implying that the Wenchuan earthquake might not be triggered directly by the seismic activities on

  6. Transportations Systems Modeling and Applications in Earthquake Engineering (United States)


    earthquake (Japan) The 1995 Hanshin-Awaji earthquake ( wM 6.8) in the Osaka -Kobe area had an even greater impact on the transportation systems compared...with the Loma Prieta and Northridge earthquakes in the U.S. The span collapses of the elevated Osaka -Kobe expressway (Route 3) caused long- time...nation’s economy and society. The numerical case study focuses on the road network in the Memphis metropolitan area. The road network information

  7. A Prospect of Earthquake Prediction Research

    CERN Document Server

    Ogata, Yosihiko


    Earthquakes occur because of abrupt slips on faults due to accumulated stress in the Earth's crust. Because most of these faults and their mechanisms are not readily apparent, deterministic earthquake prediction is difficult. For effective prediction, complex conditions and uncertain elements must be considered, which necessitates stochastic prediction. In particular, a large amount of uncertainty lies in identifying whether abnormal phenomena are precursors to large earthquakes, as well as in assigning urgency to the earthquake. Any discovery of potentially useful information for earthquake prediction is incomplete unless quantitative modeling of risk is considered. Therefore, this manuscript describes the prospect of earthquake predictability research to realize practical operational forecasting in the near future.

  8. Earthquake engineering for nuclear facilities

    CERN Document Server

    Kuno, Michiya


    This book is a comprehensive compilation of earthquake- and tsunami-related technologies and knowledge for the design and construction of nuclear facilities. As such, it covers a wide range of fields including civil engineering, architecture, geotechnical engineering, mechanical engineering, and nuclear engineering, for the development of new technologies providing greater resistance against earthquakes and tsunamis. It is crucial both for students of nuclear energy courses and for young engineers in nuclear power generation industries to understand the basics and principles of earthquake- and tsunami-resistant design of nuclear facilities. In Part I, "Seismic Design of Nuclear Power Plants", the design of nuclear power plants to withstand earthquakes and tsunamis is explained, focusing on buildings, equipment's, and civil engineering structures. In Part II, "Basics of Earthquake Engineering", fundamental knowledge of earthquakes and tsunamis as well as the dynamic response of structures and foundation ground...

  9. Injection-induced earthquakes. (United States)

    Ellsworth, William L


    Earthquakes in unusual locations have become an important topic of discussion in both North America and Europe, owing to the concern that industrial activity could cause damaging earthquakes. It has long been understood that earthquakes can be induced by impoundment of reservoirs, surface and underground mining, withdrawal of fluids and gas from the subsurface, and injection of fluids into underground formations. Injection-induced earthquakes have, in particular, become a focus of discussion as the application of hydraulic fracturing to tight shale formations is enabling the production of oil and gas from previously unproductive formations. Earthquakes can be induced as part of the process to stimulate the production from tight shale formations, or by disposal of wastewater associated with stimulation and production. Here, I review recent seismic activity that may be associated with industrial activity, with a focus on the disposal of wastewater by injection in deep wells; assess the scientific understanding of induced earthquakes; and discuss the key scientific challenges to be met for assessing this hazard.

  10. Injection-induced earthquakes (United States)

    Ellsworth, William L.


    Earthquakes in unusual locations have become an important topic of discussion in both North America and Europe, owing to the concern that industrial activity could cause damaging earthquakes. It has long been understood that earthquakes can be induced by impoundment of reservoirs, surface and underground mining, withdrawal of fluids and gas from the subsurface, and injection of fluids into underground formations. Injection-induced earthquakes have, in particular, become a focus of discussion as the application of hydraulic fracturing to tight shale formations is enabling the production of oil and gas from previously unproductive formations. Earthquakes can be induced as part of the process to stimulate the production from tight shale formations, or by disposal of wastewater associated with stimulation and production. Here, I review recent seismic activity that may be associated with industrial activity, with a focus on the disposal of wastewater by injection in deep wells; assess the scientific understanding of induced earthquakes; and discuss the key scientific challenges to be met for assessing this hazard.

  11. Italian Case Studies Modelling Complex Earthquake Sources In PSHA (United States)

    Gee, Robin; Peruzza, Laura; Pagani, Marco


    This study presents two examples of modelling complex seismic sources in Italy, done in the framework of regional probabilistic seismic hazard assessment (PSHA). The first case study is for an area centred around Collalto Stoccaggio, a natural gas storage facility in Northern Italy, located within a system of potentially seismogenic thrust faults in the Venetian Plain. The storage exploits a depleted natural gas reservoir located within an actively growing anticline, which is likely driven by the Montello Fault, the underlying blind thrust. This fault has been well identified by microseismic activity (Mseismological information. We explore the sensitivity of the hazard results to various parameters affected by epistemic uncertainty, such as ground motions prediction equations with different rupture-to-site distance metrics, fault geometry, and maximum magnitude. The second case is an innovative study, where we perform aftershock probabilistic seismic hazard assessment (APSHA) in Central Italy, following the Amatrice M6.1 earthquake of August 24th, 2016 (298 casualties) and the subsequent earthquakes of Oct 26th and 30th (M6.1 and M6.6 respectively, no deaths). The aftershock hazard is modelled using a fault source with complex geometry, based on literature data and field evidence associated with the August mainshock. Earthquake activity rates during the very first weeks after the deadly earthquake were used to calibrated an Omori-Utsu decay curve, and the magnitude distribution of aftershocks is assumed to follow a Gutenberg-Richter distribution. We apply uniform and non-uniform spatial distribution of the seismicity across the fault source, by modulating the rates as a decreasing function of distance from the mainshock. The hazard results are computed for short-exposure periods (1 month, before the occurrences of October earthquakes) and compared to the background hazard given by law (MPS04), and to observations at some reference sites. We also show the results of

  12. Scaling and Stress Release in the Darfield-Christchurch, New Zealand Earthquake Sequence (United States)

    Abercrombie, R. E.; Fry, B.; Doser, D. I.


    The Canterbury earthquake sequence began with the M7.1 Darfield earthquake in 2010, and includes the devastating M6.2 Christchurch earthquake in 2011. The high ground accelerations and damage in Christchurch suggested that the larger eartthquakes may be high stress drop events. This is consistent with the hypothesis that faults in low-strain rate regions with long inter-event times rupture in higher stress drop earthquakes. The wide magnitude range of this prolific sequence, and the high-quality recording enable us to test this. The spatial migration of the sequence, from Darfield through Christchurch and then offshore, enables us to investigate whether we can resolve any spatial or temporal variation in earthquake stress drop. An independent study of 500 aftershocks (Oth & Kaiser, 2014) found no magnitude dependence, and identified spatially varying stress drop. Such patterns can be more confidently interpreted if observed by independent studies using different approaches. We use a direct wave, empirical Green's function (EGF) approach that includes measurement uncertainties, and objective criteria for assessing the quality of each spectral ratio (Abercrombie, 2013). The large number of earthquakes in the sequence enables us to apply the same approach to a wide range of magnitudes (M~2-6) recorded at the same stations, and so minimize the effects of any systematic biases in results. In our preliminary study, we include 2500 earthquakes recorded at a number of strong motion and broadband stations. We use multiple EGFs for each event, and find 300 earthquakes with well-resolved ratios at 5 or more stations. The stress drops are magnitude independent and there is broad correlation with the results of Oth & Kaiser. We apply the same approach to a much larger data set and compare our results to those of Oth & Kaiser, and also to other regions studied using our EGF method.

  13. Disaster triggers disaster: Earthquake triggering by tropical cyclones (United States)

    Wdowinski, S.; Tsukanov, I.


    Three recent devastating earthquakes, the 1999 M=7.6 Chi-Chi (Taiwan), 2010 M=7.0 Leogane (Haiti), 2010 M=6.4 Kaohsiung (Taiwan), and additional three moderate size earthquakes (6cyclones (hurricane or typhoon) hit the very same area. The most familiar example is Haiti, which was hit during the late summer of 2008 by two hurricanes and two tropical storms (Fay, Gustav, Hanna and Ike) within 25 days. A year an a half after this very wet hurricane season, the 2010 Leogane earthquake occurred in the mountainous Haiti's southern peninsula and caused the death of more than 300,000 people. The other cases are from Taiwan, which is characterized by a high seismicity level and frequent typhoon landfall. The three wettest typhoons in Taiwan's past 50 years were Morakot (in 2009, with 2885 mm or rain), Flossie (1969, 2162 mm) and Herb (1996, 1987 mm)[Lin et al., 2010]. Each of this three very wet storms was followed by one or two main-shock M>6 earthquake that occurred in the central mountainous area of Taiwan within three years after the typhoon. The 2009 Morakot typhoon was followed by 2009 M=6.2 Nantou and 2010 M=6.4 Kaohsiung earthquakes; the 1969 Flossie typhoon was followed by an M=6.3 earthquake in 1972; and the 1996 Herb typhoon by the 1998 M=6.2 Rueyli and 1999 M=7.6 Chi-Chi earthquakes. The earthquake catalog of Taiwan lists only two other M>6 main-shocks that occurred in Taiwan's central mountainous belt, one of them was in 1964 only four months after the wet Typhoon Gloria poured heavy rain in the same area. We suggest that the close proximity in time and space between wet tropical cyclones and earthquakes reflects a physical link between the two hazard types in which these earthquakes were triggered by rapid erosion induced by tropical cyclone's heavy rain. Based on remote sensing observations, meshfree finite element modeling, and Coulomb failure stress analysis, we show that the erosion induced by very wet cyclones increased the failure stresses at the

  14. Spatial Verification of Earthquake Simulators Using Self-Consistent Metrics for Off-Fault Seismicity (United States)

    Wilson, J. M.; Yoder, M. R.; Rundle, J. B.


    We address the problem of verifying the self-consistency of earthquake simulators with the data from which their parameters are drawn. Earthquake simulators are a class of computational simulations which attempt to mirror the topological complexity of the earthquake fault system on which the earthquakes occur. In addition, the physics of friction and elastic interactions between fault elements can be included in these simulations as well. In general, the parameters are adjusted so that natural earthquake sequences are matched in their scaling properties in an optimal way. Generally, these parameters choices are based on paleoseismic data extending over many hundreds and thousands of years. However, one of the problems encountered is the verification of the simulations applied to current earthquake seismicity. It is this problem, for which no currently accepted solution has been proposed, that is the objective of the present paper. Physically-based earthquake simulators allow the generation of many thousands of years of simulated seismicity, allowing for robust capture of statistical properties of large, damaging earthquakes that have long recurrence time scales for observation. Following past simulator and forecast model verification efforts, we approach the challenges in spatial forecast verification fo simulators; namely, that simulator output events are confined to the modeled faults, while observed earthquakes often occur off of known faults. We present two methods for overcoming this discrepancy: a simplistic approach whereby observed earthquakes are shifted to the nearest fault element and a variation of the Epidemic-type aftershock (ETAS) model, which smears the simulator catalog seismicity over the entire test region. To test these methods, a Receiver Operating Characteristic (ROC) plot was produced by comparing the rate maps to observed m>6.0 earthquakes since 1980. We found that the nearest-neighbor mapping produced poor forecasts, while the modified ETAS

  15. Potential for a large earthquake near Los Angeles inferred from the 2014 La Habra earthquake (United States)

    Grant Ludwig, Lisa; Parker, Jay W.; Rundle, John B.; Wang, Jun; Pierce, Marlon; Blewitt, Geoffrey; Hensley, Scott


    Abstract Tectonic motion across the Los Angeles region is distributed across an intricate network of strike‐slip and thrust faults that will be released in destructive earthquakes similar to or larger than the 1933 M6.4 Long Beach and 1994 M6.7 Northridge events. Here we show that Los Angeles regional thrust, strike‐slip, and oblique faults are connected and move concurrently with measurable surface deformation, even in moderate magnitude earthquakes, as part of a fault system that accommodates north‐south shortening and westerly tectonic escape of northern Los Angeles. The 28 March 2014 M5.1 La Habra earthquake occurred on a northeast striking, northwest dipping left‐lateral oblique thrust fault northeast of Los Angeles. We present crustal deformation observation spanning the earthquake showing that concurrent deformation occurred on several structures in the shallow crust. The seismic moment of the earthquake is 82% of the total geodetic moment released. Slip within the unconsolidated upper sedimentary layer may reflect shallow release of accumulated strain on still‐locked deeper structures. A future M6.1–6.3 earthquake would account for the accumulated strain. Such an event could occur on any one or several of these faults, which may not have been identified by geologic surface mapping. PMID:27981074


    Institute of Scientific and Technical Information of China (English)

    李玉丽; 李启雷; 杨广华; 谢庆和; 朱胜伟


    Abstract:The basic situation of Golmud fluid well and digitalization instruments are introduced, and the digi- tal data and the anomalous characteristics of three earthquakes with Ms≥6. 0 near Golmud are analyzed, the results show that the anomalies are quite different before different earthquakes, and they may be related to re- gional tectonics. The amonalies of other observation items in the well are also quite different.%介绍了格尔木流体观测井及数字化仪器的基本情况,对数字化观测资料进行了初步分析,并分析了格尔木周边3次6级以上地震前的异常特征,结果显示:同一方法提取的异常在不同地震前差别较大,且异常可能与区域构造相关。对于该观测井不同测项,震前的异常差异也较大。

  17. Are segment boundaries of subduction earthquakes structurally controlled? Evidences from the Ecuador-Colombia 20th century earthquake sequence (United States)

    Collot, J.-Y.; Marcaillou, B.; Sage, F.; Gutscher, M.-A.; Charvis, P.; Michaud, F.


    , and across a highly deformed outer ridge, indicating a relatively weak margin/strong plate inter-face. In addition to separating areas of differing long-term deformation, MF appears to serve as location for high stress concentration during the earthquake cycle as indicated by the clustering of 1958 aftershock events of M=~6.0 near the fault. These data show that the MF controls the rupture zone of subduction earthquakes of Mw 7.7 to 8.2, by decoupling the tectonic blocks of the margin from the underlying plate interface.

  18. Earthquake Hazards Program: Earthquake Scenarios (United States)

    U.S. Geological Survey, Department of the Interior — A scenario represents one realization of a potential future earthquake by assuming a particular magnitude, location, and fault-rupture geometry and estimating...

  19. Some characteristics of the complex El Mayor-Cucapah, MW7.2, April 4, 2010, Baja California, Mexico, earthquake, from well-located aftershock data from local and regional networks. (United States)

    Frez, J.; Nava Pichardo, F. A.; Acosta, J.; Munguia, L.; Carlos, J.; García, R.


    Aftershocks from the El Mayor-Cucapah (EMC), MW7.2, April 4, 2010, Baja California, Mexico, earthquake, were recorded over two months by a 31 station local array (Reftek RT130 seismographs loaned from IRIS-PASSCAL), complemented by regional data from SCSN, and CICESE. The resulting data base includes 518 aftershocks with ML ≥ 3.0, plus 181 smaller events. Reliable hypocenters were determined using HYPODD and a velocity structure determined from refraction data for a mesa located to the west of the Mexicali-Imperial Valley. Aftershock hypocenters show that the El Mayor-Cucapah earthquake was a multiple event comprising two or three different ruptures of which the last one constituted the main event. The main event rupture, which extends in a roughly N45°W direction, is complex with well-defined segments having different characteristics. The main event central segment, located close to the first event epicenter is roughly vertical, the northwest segment dips ~68°NE, while the two southeast segments dip ~60°SW and ~52°SW, respectively, which agrees with results of previous studies based on teleseismic long periods and on GPS-INSAR. All main rupture aftershock hypocenters have depths above 10-11km and, except for the central segment, they delineate the edges of zones with largest coseismic displacement. The two southern segments show seismicity concentrated below 5km and 3.5km, respectively; the paucity of shallow seismicity may be caused by the thick layer of non-consolidated sediments in this region. The ruptures delineated by aftershocks in the southern regions correspond to the Indiviso fault, unidentified until the occurrence of the EMC earthquake. The first event was relocated together with the aftershocks; the epicenter lies slightly westwards of published locations, but it definitely does not lie on, or close to, the main rupture. The focal mechanism of the first event, based on first arrival polarities, is predominantly strike-slip; the focal plane

  20. Stress drops and radiated energies of aftershocks of the 1994 Northridge, California, earthquake (United States)

    Mori, Jim; Abercrombie, Rachel E.; Kanamori, Hiroo


    We study stress levels and radiated energy to infer the rupture characteristics and scaling relationships of aftershocks and other southern California earthquakes. We use empirical Green functions to obtain source time functions for 47 of the larger (M ≥ 4.0) aftershocks of the 1994 Northridge, California earthquake (M6.7). We estimate static and dynamic stress drops from the source time functions and compare them to well-calibrated estimates of the radiated energy. Our measurements of radiated energy are relatively low compared to the static stress drops, indicating that the static and dynamic stress drops are of similar magnitude. This is confirmed by our direct estimates of the dynamic stress drops. Combining our results for the Northridge aftershocks with data from other southern California earthquakes appears to show an increase in the ratio of radiated energy to moment, with increasing moment. There is no corresponding increase in the static stress drop. This systematic change in earthquake scaling from smaller to larger (M3 to M7) earthquakes suggests differences in rupture properties that may be attributed to differences of dynamic friction or stress levels on the faults.

  1. Earthquake and Geothermal Energy

    CERN Document Server

    Kapoor, Surya Prakash


    The origin of earthquake has long been recognized as resulting from strike-slip instability of plate tectonics along the fault lines. Several events of earthquake around the globe have happened which cannot be explained by this theory. In this work we investigated the earthquake data along with other observed facts like heat flow profiles etc... of the Indian subcontinent. In our studies we found a high-quality correlation between the earthquake events, seismic prone zones, heat flow regions and the geothermal hot springs. As a consequence, we proposed a hypothesis which can adequately explain all the earthquake events around the globe as well as the overall geo-dynamics. It is basically the geothermal power, which makes the plates to stand still, strike and slip over. The plates are merely a working solid while the driving force is the geothermal energy. The violent flow and enormous pressure of this power shake the earth along the plate boundaries and also triggers the intra-plate seismicity. In the light o...

  2. Geoelectric Anomalies Preceding the Aug. 24 2016 Amatrice, Italy Earthquake (United States)

    Scoville, J.; Bobrovskiy, V.; Freund, F. T.


    We report on geoelectric measurements taken at 70 and 120 km from the epicenter of the M6.2 Amatrice Central Italy Earthquake Aug. 24, 2016. Two stations, each consisting of 12 buried electrodes at depths of 1 to 3 meters, recorded ground EMF values once per second for approximately one year prior to the earthquake. Several geoelectric anomalies suggest the incidence of seismic electric signals in the weeks leading up to the earthquake. Notably, EMF values in the DC regime deviated progressively farther from baseline levels and AC components exhibited episodes of significant nonstationarity in their frequency spectra as the earthquake approached.

  3. Sense of Community and Depressive Symptoms among Older Earthquake Survivors Following the 2008 Earthquake in Chengdu China (United States)

    Li, Yawen; Sun, Fei; He, Xusong; Chan, Kin Sun


    This study examined the impact of an earthquake as well as the role of sense of community as a protective factor against depressive symptoms among older Chinese adults who survived an 8.0 magnitude earthquake in 2008. A household survey of a random sample was conducted 3 months after the earthquake and 298 older earthquake survivors participated…

  4. Sense of Community and Depressive Symptoms among Older Earthquake Survivors Following the 2008 Earthquake in Chengdu China (United States)

    Li, Yawen; Sun, Fei; He, Xusong; Chan, Kin Sun


    This study examined the impact of an earthquake as well as the role of sense of community as a protective factor against depressive symptoms among older Chinese adults who survived an 8.0 magnitude earthquake in 2008. A household survey of a random sample was conducted 3 months after the earthquake and 298 older earthquake survivors participated…

  5. Relationship between coping style and perceived general well-being among teachers in earthquake disaster area of Sichuan province%四川震区教师应对方式与总体幸福感关系

    Institute of Scientific and Technical Information of China (English)

    梁斌; 孙建


    Objective To investigate the relationship between coping style and perceived general well-being among the teachers in earthquake disaster area of Sichuan province. Methods A sample of 741 teachers in the earthquake disaster area was investigated using Coping Style Questionnaire and General Weil-Being Scale. Results The differences in coping style between the teachers of different gender and age were statistically significant (P < 0.05) and the differences in perceived general well-being between the teachers of different age,education,and working area after the earthquake were statistically significant (P < 0.05). The correlation coefficients of coping style and perceived general well-being were between - 0.02 -0.37 (P < 0.05 or P < 0.01). The correlation between coping style (immature, mixed) and perceived general well-being was negative. The immature and mature coping style could predict perceived general well-being. Conclusion The male teachers needed more attention than the females on coping style and perceived general well-being. The coping style can predict perceived general well-being of the teachers in earthquake disaster area.%目的 了解四川震区教师应对方式与总体幸福感的现状及关系.方法 使用应对方式问卷和总体幸福感量表对四川地震灾区741名教师进行调查.结果 震区教师应对方式在性别、年龄上差异有统计学意义(P<0.05);总体幸福感在性别、学历以及灾后教学场所上差异有统计学意义(P<0.05);除对生活的满足和兴趣维度,应对方式与总体幸福感各维度呈不同程度的相关关系(r=-0.02~0.37,P<0.05或P<0.01);不成熟型和混合型的应对方式与总体幸福感各维度均呈现负相关;不成熟型、成熟型的应对方式对总体幸福感有预测效果.结论 在应付方式和总体幸福感方面,震区男教师比女教师面临更多的问题;震区教师应对方式对其总体幸福感有一定预测作用.

  6. Bounding Ground Motions for Hayward Fault Scenario Earthquakes Using Suites of Stochastic Rupture Models (United States)

    Rodgers, A. J.; Xie, X.; Petersson, A.


    The next major earthquake in the San Francisco Bay area is likely to occur on the Hayward-Rodgers Creek Fault system. Attention on the southern Hayward section is appropriate given the upcoming 140th anniversary of the 1868 M 7 rupture coinciding with the estimated recurrence interval. This presentation will describe ground motion simulations for large (M > 6.5) earthquakes on the Hayward Fault using a recently developed elastic finite difference code and high-performance computers at Lawrence Livermore National Laboratory. Our code easily reads the recent USGS 3D seismic velocity model of the Bay Area developed in 2005 and used for simulations of the 1906 San Francisco and 1989 Loma Prieta earthquakes. Previous work has shown that the USGS model performs very well when used to model intermediate period (4-33 seconds) ground motions from moderate (M ~ 4-5) earthquakes (Rodgers et al., 2008). Ground motions for large earthquakes are strongly controlled by the hypocenter location, spatial distribution of slip, rise time and directivity effects. These are factors that are impossible to predict in advance of a large earthquake and lead to large epistemic uncertainties in ground motion estimates for scenario earthquakes. To bound this uncertainty, we are performing suites of simulations of scenario events on the Hayward Fault using stochastic rupture models following the method of Liu et al. (Bull. Seism. Soc. Am., 96, 2118-2130, 2006). These rupture models have spatially variable slip, rupture velocity, rise time and rake constrained by characterization of inferred finite fault ruptures and expert opinion. Computed ground motions show variability due to the variability in rupture models and can be used to estimate the average and spread of ground motion measures at any particular site. This work was performed under the auspices of the U.S. Department of Energy by University of California Lawrence Livermore National Laboratory under contract No.W-7405-Eng-48. This is

  7. Distribution characteristics of earthquake-induced landslide with the earthquake source fault-the cases of recent strong earthquakes in eastern Japan (United States)

    Hasi, B.; Ishii, Y.; Maruyama, K.; Terada, H.


    In recent years, 3 strong earthquakes, the Mid-Niigata earthquake (M6.8, October 23, 2004), the Noto Peninsula earthquake (M6.9, March 25, 2007), the Chuetsu-offshore earthquake (M6.8, July 16, 2007), stroke eastern Japan. All of these earthquakes occurred inland by reverse fault, with depth 11-17km hypocenter, triggered a large number of landslides and caused serious damage to the involved regions due to these landslides. To clarify the distribution characteristics of landslides induced by these earthquakes, we interpreted landslides by using aerial photographs taken immediately after the earthquakes, and analyzed landslide distributions with the peak ground acceleration (PGA) and seismic intensity (in Japan Meteorological Agency intensity scale), source fault of the mainshock of each earthquake. The analyzing results revealed that: 1) Most of the landslides occurred in the area where the PGA is larger than 500 gal, and the maximum seismic intensity is larger than 5 plus ; 2) The landslides occurred in a short distance from the source fault (the shortest distance from the surface projection of top tip of the fault), about 80% occurred within the distance of 20 km; 3) More than 80% of landslides occurred on the hanging wall, and the size of landslide (length, width, area) is larger than that occurred on the footwall of the source fault; 4) The number and size of landslide tends to deceases with the distance from the source fault. Our results suggesting that the distance from the source fault of earthquake could be a parameter to analyze the landslide occurrence induce by strong earthquake.

  8. Earthquake engineering research: 1982 (United States)

    The Committee on Earthquake Engineering Research addressed two questions: What progress has research produced in earthquake engineering and which elements of the problem should future earthquake engineering pursue. It examined and reported in separate chapters of the report: Applications of Past Research, Assessment of Earthquake Hazard, Earthquake Ground Motion, Soil Mechanics and Earth Structures, Analytical and Experimental Structural Dynamics, Earthquake Design of Structures, Seismic Interaction of Structures and Fluids, Social and Economic Aspects, Earthquake Engineering Education, Research in Japan.

  9. Fractal Models of Earthquake Dynamics

    CERN Document Server

    Bhattacharya, Pathikrit; Kamal,; Samanta, Debashis


    Our understanding of earthquakes is based on the theory of plate tectonics. Earthquake dynamics is the study of the interactions of plates (solid disjoint parts of the lithosphere) which produce seismic activity. Over the last about fifty years many models have come up which try to simulate seismic activity by mimicking plate plate interactions. The validity of a given model is subject to the compliance of the synthetic seismic activity it produces to the well known empirical laws which describe the statistical features of observed seismic activity. Here we present a review of two such models of earthquake dynamics with main focus on a relatively new model namely The Two Fractal Overlap Model.

  10. Relation between the characteristics of strong earthquake activities in Chinese mainland and the Wenchuan earthquake

    Institute of Scientific and Technical Information of China (English)

    Xiaodong Zhang; Guohua Yang; Xian Lu; Mingxiao Li; Zhigao Yang


    This paper studies the relations between the great Wenchuan earthquake and the active-quiet periodic characteristics of strong earthquakes, the rhythmic feature of great earthquakes, and the grouped spatial distribution of MS8.0 earthquakes in Chinese mainland. We also studied the relation between the Wenchuan earthquake and the stepwise migration characteristics of MS≥7.0 earthquakes on the North-South seismic belt, the features of the energy releasing acceleration in the active crustal blocks related to the Wenchuan earthquake and the relation between the Wenchuan earthquake and the so called second-arc fault zone. The results can be summarized as follows: ① the occurrence of the Wenchuan earthquake was consistent with the active-quiet periodic characteristics of strong earthquakes; ② its occurrence is consistent with the features of grouped occurrence of MS8.0 earthquakes and follows the 25 years rhythm (each circulation experiences the same time) of great earthquakes; ③ the Wenchuan MS8.0 earthquake follows the well known stepwise migration feature of strong earthquakes on the North-South seismic belt; ④ the location where the Wenchuan MS8.0 earthquake took place has an obvious consistency with the temporal and spatial characteristic of grouped activity of MS≥7.0 strong earthquakes on the second-arc fault zone; ⑤ the second-arc fault zone is not only the lower boundary for earthquakes with more than 30 km focal depth, but also looks like a lower boundary for deep substance movement; and ⑥ there are obvious seismic accelerations nearby the Qaidam and Qiangtang active crustal blocks (the northern and southern neighbors of the Bayan Har active block, respectively), which agrees with the GPS observation data.

  11. Joint Inversion of Earthquake Source Parameters with local and teleseismic body waves (United States)

    Chen, W.; Ni, S.; Wang, Z.


    In the classical source parameter inversion algorithm of CAP (Cut and Paste method, by Zhao and Helmberger), waveform data at near distances (typically less than 500km) are partitioned into Pnl and surface waves to account for uncertainties in the crustal models and different amplitude weight of body and surface waves. The classical CAP algorithms have proven effective for resolving source parameters (focal mechanisms, depth and moment) for earthquakes well recorded on relatively dense seismic network. However for regions covered with sparse stations, it is challenging to achieve precise source parameters . In this case, a moderate earthquake of ~M6 is usually recorded on only one or two local stations with epicentral distances less than 500 km. Fortunately, an earthquake of ~M6 can be well recorded on global seismic networks. Since the ray paths for teleseismic and local body waves sample different portions of the focal sphere, combination of teleseismic and local body wave data helps constrain source parameters better. Here we present a new CAP mothod (CAPjoint), which emploits both teleseismic body waveforms (P and SH waves) and local waveforms (Pnl, Rayleigh and Love waves) to determine source parameters. For an earthquake in Nevada that is well recorded with dense local network (USArray stations), we compare the results from CAPjoint with those from the traditional CAP method involving only of local waveforms , and explore the efficiency with bootstraping statistics to prove the results derived by CAPjoint are stable and reliable. Even with one local station included in joint inversion, accuracy of source parameters such as moment and strike can be much better improved.

  12. Fracking, wastewater disposal, and earthquakes (United States)

    McGarr, Arthur


    In the modern oil and gas industry, fracking of low-permeability reservoirs has resulted in a considerable increase in the production of oil and natural gas, but these fluid-injection activities also can induce earthquakes. Earthquakes induced by fracking are an inevitable consequence of the injection of fluid at high pressure, where the intent is to enhance permeability by creating a system of cracks and fissures that allow hydrocarbons to flow to the borehole. The micro-earthquakes induced during these highly-controlled procedures are generally much too small to be felt at the surface; indeed, the creation or reactivation of a large fault would be contrary to the goal of enhancing permeability evenly throughout the formation. Accordingly, the few case histories for which fracking has resulted in felt earthquakes have been due to unintended fault reactivation. Of greater consequence for inducing earthquakes, modern techniques for producing hydrocarbons, including fracking, have resulted in considerable quantities of coproduced wastewater, primarily formation brines. This wastewater is commonly disposed by injection into deep aquifers having high permeability and porosity. As reported in many case histories, pore pressure increases due to wastewater injection were channeled from the target aquifers into fault zones that were, in effect, lubricated, resulting in earthquake slip. These fault zones are often located in the brittle crystalline rocks in the basement. Magnitudes of earthquakes induced by wastewater disposal often exceed 4, the threshold for structural damage. Even though only a small fraction of disposal wells induce earthquakes large enough to be of concern to the public, there are so many of these wells that this source of seismicity contributes significantly to the seismic hazard in the United States, especially east of the Rocky Mountains where standards of building construction are generally not designed to resist shaking from large earthquakes.

  13. Induced earthquake during the 2016 Kumamoto earthquake (Mw7.0): Importance of real-time shake monitoring for Earthquake Early Warning (United States)

    Hoshiba, M.; Ogiso, M.


    Sequence of the 2016 Kumamoto earthquakes (Mw6.2 on April 14, Mw7.0 on April 16, and many aftershocks) caused a devastating damage at Kumamoto and Oita prefectures, Japan. During the Mw7.0 event, just after the direct S waves passing the central Oita, another M6 class event occurred there more than 80 km apart from the Mw7.0 event. The M6 event is interpreted as an induced earthquake; but it brought stronger shaking at the central Oita than that from the Mw7.0 event. We will discuss the induced earthquake from viewpoint of Earthquake Early Warning. In terms of ground shaking such as PGA and PGV, the Mw7.0 event is much smaller than those of the M6 induced earthquake at the central Oita (for example, 1/8 smaller at OIT009 station for PGA), and then it is easy to discriminate two events. However, PGD of the Mw7.0 is larger than that of the induced earthquake, and its appearance is just before the occurrence of the induced earthquake. It is quite difficult to recognize the induced earthquake from displacement waveforms only, because the displacement is strongly contaminated by that of the preceding Mw7.0 event. In many methods of EEW (including current JMA EEW system), magnitude is used for prediction of ground shaking through Ground Motion Prediction Equation (GMPE) and the magnitude is often estimated from displacement. However, displacement magnitude does not necessarily mean the best one for prediction of ground shaking, such as PGA and PGV. In case of the induced earthquake during the Kumamoto earthquake, displacement magnitude could not be estimated because of the strong contamination. Actually JMA EEW system could not recognize the induced earthquake. One of the important lessons we learned from eight years' operation of EEW is an issue of the multiple simultaneous earthquakes, such as aftershocks of the 2011 Mw9.0 Tohoku earthquake. Based on this lesson, we have proposed enhancement of real-time monitor of ground shaking itself instead of rapid estimation of

  14. Earthquake Relief Work: Reflecting CPC' s High Care about People's Well-being%抗震救灾:彰显中国共产党对民生的高度关注

    Institute of Scientific and Technical Information of China (English)



    民生问题是当今中国社会各界共同关注的热点问题,也是中国共产党一贯致力于妥善解决的重大问题.汶川地震的抗震救灾,。民生问题”始终如一地贯穿于整个过程中,彰显了中国共产党对民生问题的高度关注,表达了党与人民群众同呼吸、共命运、共患难、心连心的情怀,同时也显示了中国共产党具有解决民生问题的非凡能力.%People's well-being, the hot issue concerned by the whole Chinese society, is an important problem that the CPC has been working on. The relief work of the Wenchuan earthquake through which this issue went indicated CPC's high care about people's well-being, expressed CPC's mind to maintain a heart-to-heart relationship with people and demonstrated that CPC has the extraordinary capacity to solve the problem of people's well-being.

  15. Connecting slow earthquakes to huge earthquakes. (United States)

    Obara, Kazushige; Kato, Aitaro


    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.

  16. Connecting slow earthquakes to huge earthquakes (United States)

    Obara, Kazushige; Kato, Aitaro


    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.

  17. Application of the M6T Tracker to Simulated and Experimental Multistatic Sonar Data

    NARCIS (Netherlands)

    Theije, P.A.M. de; Kester, L.J.H.M.; Bergmans, J.


    This paper describes the first results of applying a multi-sensor multi-hypothesis tracker, called M6T, to simulated and experimental sonar data sets. The simulated data have been generated in the context of the Multistatic Tracking Working Group (MSTWG). For a number of cases (number of sensors and

  18. Structures of the m(6)A Methyltransferase Complex: Two Subunits with Distinct but Coordinated Roles. (United States)

    Zhou, Katherine I; Pan, Tao


    In this issue of Molecular Cell, Wang et al. (2016a) report crystal structures of the core of the METTL3/METTL14 m(6)A methyltransferase complex and propose how the two subunits interact and cooperate to bind and methylate RNA.


    Directory of Open Access Journals (Sweden)

    I. I. Lipatov


    Full Text Available Introduction to the results of a numerical study buffeting on Onera M6 wing. The determination of condition to appear buffeting of the modes of oscillation of a shock when interacting with in the boundary layer at Mach numbers and angles of attack.

  20. Genome Sequence of Selenium-Solubilizing Bacterium Caulobacter vibrioides T5M6

    DEFF Research Database (Denmark)

    Wang, Yihua; Qin, Yanan; Kot, Witold


    Caulobacter vibrioides T5M6 is a Gram-negative strain that strongly solubilizes selenium (Se) mineral into Se(IV) and was isolated from a selenium mining area in Enshi, southwest China. This strain produces the phytohormone IAA and promotes plant growth. Here we present the genome of this strain ...

  1. A Preliminary Study on the Medium Term Anomalies of Groundwater Level of Luzhou Well and the Tentative Index for Earthquake Prediction%泸州井地下水位中期异常特征和试用性预测指标的初步研究

    Institute of Scientific and Technical Information of China (English)

    李雅蓉; 杨贤和


    The seismic behavior monitoring of groundwater in China has over 40 years history .Co‐operated with other precursor means ,it has become one important means of all means for earth‐quake prediction .But the earthquake‐reflecting condition of each well and the evaluation of them is different .People have different views on the revocation of Luzhou well in recent years .This pa‐per selects historical target earthquakes based on the earthquake cycle and magnitude in Sichuan and Yunnnan area .We use the method combining qualitative (monthly average method) and quantitative (23 points smoothing method and subordinate function method) approaches to make a systematic analysis on monthly observation data of Luzhou well groundwater level from 1982 to 2014 .We found 6 middle‐term anomalistic changes ,respectively ,corresponding to one M S 6 .6 earthquake occurred at Batang in 1989 and five strong earthquakes including Wenchuan M S 8 .0 earthquake .Among these 6 middle‐term anomalies ,2 anomalies belong in the Wenchuan M S 8 .0 earthquake .Also ,these anomalies were tested by R value .Compared with other wells in Sichuan and Yunnan Province ,facts have proved that the middle‐term anomalies of Luzhou well water level are obvious ,and are not unique case .In addition ,the particularity of anomaly before the Wenchuan earthquake and post the Wenchuan earthquake is discussed .That is ,second anomaly ,and post the Wenchuan earthquake effect is remarkable and lasting .We use the statistical data and the subordinate function of the water level of Luzhou well to calculate the tentative index for middle‐term prediction on the occurrence of earthquake .The index can be used to predict the peri‐od when a strong earthquake can most likely occur in Sichuan and Yunnan area .Finally ,we come up a conclusion that Luzhou well can be used to perform a study on middle‐term anomaly and pre‐diction on strong earthquakes while there need to strengthen the management and study

  2. Is Earthquake Triggering Driven by Small Earthquakes?

    CERN Document Server

    Helmstetter, A


    Using a catalog of seismicity for Southern California, we measure how the number of triggered earthquakes increases with the earthquake magnitude. The trade-off between this scaling and the distribution of earthquake magnitudes controls the relative role of small compared to large earthquakes. We show that seismicity triggering is driven by the smallest earthquakes, which trigger fewer aftershocks than larger earthquakes, but which are much more numerous. We propose that the non-trivial scaling of the number of aftershocks emerges from the fractal spatial distribution of aftershocks.

  3. Earthquake Hazard Mitigation Strategy in Indonesia (United States)

    Karnawati, D.; Anderson, R.; Pramumijoyo, S.


    Because of the active tectonic setting of the region, the risks of geological hazards inevitably increase in Indonesian Archipelagoes and other ASIAN countries. Encouraging community living in the vulnerable area to adapt with the nature of geology will be the most appropriate strategy for earthquake risk reduction. Updating the Earthquake Hazard Maps, enhancement ofthe existing landuse management , establishment of public education strategy and method, strengthening linkages among stake holders of disaster mitigation institutions as well as establishement of continues public consultation are the main strategic programs for community resilience in earthquake vulnerable areas. This paper highlights some important achievements of Earthquake Hazard Mitigation Programs in Indonesia, together with the difficulties in implementing such programs. Case examples of Yogyakarta and Bengkulu Earthquake Mitigation efforts will also be discussed as the lesson learned. The new approach for developing earthquake hazard map which is innitiating by mapping the psychological aspect of the people living in vulnerable area will be addressed as well.

  4. 2010 Chile Earthquake Aftershock Response (United States)

    Barientos, Sergio


    1906? Since the number of M>7.0 aftershocks has been low, does the distribution of large-magnitude aftershocks differ from previous events of this size? What is the origin of the extensional-type aftershocks at shallow depths within the upper plate? The international seismological community (France, Germany, U.K., U.S.A.) in collaboration with the Chilean seismological community responded with a total of 140 portable seismic stations to deploy in order to record aftershocks. This combined with the Chilean permanent seismic network, in the area results in 180 stations now in operation recording continuous at 100 cps. The seismic equipment is a mix of accelerometers, short -period and broadband seismic sensors deployed along the entire length of the aftershock zone that will record the aftershock sequence for three to six months. The collected seismic data will be merged and archived to produce an international data set open to the entire seismological community immediately after archiving. Each international group will submit their data as soon as possible in standard (mini seed) format with accompanying meta data to the IRIS DMC where the data will be merged into a combined data set and available to individuals and other data centers. This will be by far the best-recorded aftershock sequence of a large megathrust earthquake. This outstanding international collaboration will provide an open data set for this important earthquake as well as provide a model for future aftershock deployments around the world.

  5. Predictable earthquakes? (United States)

    Martini, D.


    acceleration) and global number of earthquake for this period from published literature which give us a great picture about the dynamical geophysical phenomena. Methodology: The computing of linear correlation coefficients gives us a chance to quantitatively characterise the relation among the data series, if we suppose a linear dependence in the first step. The correlation coefficients among the Earth's rotational acceleration and Z-orbit acceleration (perpendicular to the ecliptic plane) and the global number of the earthquakes were compared. The results clearly demonstrate the common feature of both the Earth's rotation and Earth's Z-acceleration around the Sun and also between the Earth's rotational acceleration and the earthquake number. This fact might means a strong relation among these phenomena. The mentioned rather strong correlation (r = 0.75) and the 29 year period (Saturn's synodic period) was clearly shown in the counted cross correlation function, which gives the dynamical characteristic of correlation, of Earth's orbital- (Z-direction) and rotational acceleration. This basic period (29 year) was also obvious in the earthquake number data sets with clear common features in time. Conclusion: The Core, which involves the secular variation of the Earth's magnetic field, is the only sufficiently mobile part of the Earth with a sufficient mass to modify the rotation which probably effects on the global time distribution of the earthquakes. Therefore it might means that the secular variation of the earthquakes is inseparable from the changes in Earth's magnetic field, i.e. the interior process of the Earth's core belongs to the dynamical state of the solar system. Therefore if the described idea is real the global distribution of the earthquakes in time is predictable.

  6. Defeating Earthquakes (United States)

    Stein, R. S.


    The 2004 M=9.2 Sumatra earthquake claimed what seemed an unfathomable 228,000 lives, although because of its size, we could at least assure ourselves that it was an extremely rare event. But in the short space of 8 years, the Sumatra quake no longer looks like an anomaly, and it is no longer even the worst disaster of the Century: 80,000 deaths in the 2005 M=7.6 Pakistan quake; 88,000 deaths in the 2008 M=7.9 Wenchuan, China quake; 316,000 deaths in the M=7.0 Haiti, quake. In each case, poor design and construction were unable to withstand the ferocity of the shaken earth. And this was compounded by inadequate rescue, medical care, and shelter. How could the toll continue to mount despite the advances in our understanding of quake risk? The world's population is flowing into megacities, and many of these migration magnets lie astride the plate boundaries. Caught between these opposing demographic and seismic forces are 50 cities of at least 3 million people threatened by large earthquakes, the targets of chance. What we know for certain is that no one will take protective measures unless they are convinced they are at risk. Furnishing that knowledge is the animating principle of the Global Earthquake Model, launched in 2009. At the very least, everyone should be able to learn what his or her risk is. At the very least, our community owes the world an estimate of that risk. So, first and foremost, GEM seeks to raise quake risk awareness. We have no illusions that maps or models raise awareness; instead, earthquakes do. But when a quake strikes, people need a credible place to go to answer the question, how vulnerable am I, and what can I do about it? The Global Earthquake Model is being built with GEM's new open source engine, OpenQuake. GEM is also assembling the global data sets without which we will never improve our understanding of where, how large, and how frequently earthquakes will strike, what impacts they will have, and how those impacts can be lessened by

  7. Earthquake Risk Management of Underground Lifelines in the Urban Area of Catania (United States)

    Grasso, S.; Maugeri, M.


    Lifelines typically include the following five utility networks: potable water, sewage natural gas, electric power, telecommunication and transportation system. The response of lifeline systems, like gas and water networks, during a strong earthquake, can be conveniently evaluated with the estimated average number of ruptures per km of pipe. These ruptures may be caused either by fault ruptures crossing, or by permanent deformations of the soil mass (landslides, liquefaction), or by transient soil deformations caused by seismic wave propagation. The possible consequences of damaging earthquakes on transportation systems may be the reduction or the interruption of traffic flow, as well as the impact on the emergency response and on the recovery assistance. A critical element in the emergency management is the closure of roads due to fallen obstacles and debris of collapsed buildings. The earthquake-induced damage to buried pipes is expressed in terms of repair rate (RR), defined as the number of repairs divided by the pipe length (km) exposed to a particular level of seismic demand; this number is a function of the pipe material (and joint type), of the pipe diameter and of the ground shaking level, measured in terms of peak horizontal ground velocity (PGV) or permanent ground displacement (PGD). The development of damage algorithms for buried pipelines is primarily based on empirical evidence, tempered with engineering judgment and sometimes by analytical formulations. For the city of Catania, in the present work use has been made of the correlation between RR and peak horizontal ground velocity by American Lifelines Alliance (ALA, 2001), for the verifications of main buried pipelines. The performance of the main buried distribution networks has been evaluated for the Level I earthquake scenario (January 11, 1693 event I = XI, M 7.3) and for the Level II earthquake scenario (February 20, 1818 event I = IX, M 6.2). Seismic damage scenario of main gas pipelines and

  8. Using a physics-based earthquake simulator to evaluate seismic hazard in NW Iran (United States)

    Khodaverdian, A.; Zafarani, H.; Rahimian, M.


    NW Iran is a region of active deformation in the Eurasia-Arabia collision zone. This high strain field has caused intensive faulting accompanied by several major (M > 6.5) earthquakes as it is evident from historical records. Whereas seismic data (i.e. instrumental and historical catalogues) are either short, or inaccurate and inhomogeneous, physics-based long-term simulations are beneficial to better assess seismic hazard. In this study, a deterministic seismicity model, which consists of major active faults, is first constructed, and used to generate a synthetic catalogue of large-magnitude (M > 5.5) earthquakes. The frequency-magnitude distribution of the synthetic earthquake catalogue, which is based on the physical characteristic and slip rate of the mapped faults, is consistent with the empirical distribution evaluated using record of instrumental and historical events. The obtained results are also in accordance with palaeoseismic studies and other independent kinematic deformation models of the Iranian Plateau. Using the synthetic catalogue, characteristic magnitude for all 16 active faults in the study area is determined. Magnitude and epicentre of these earthquakes are comparable with the historical records. Large earthquake recurrence times and their variations are evaluated, either for an individual fault or for the region as a whole. Goodness-of-fitness tests revealed that recurrence times can be well described by the Weibull distribution. Time-dependent conditional probabilities for large earthquakes in the study area are also estimated for different time intervals. The resulting synthetic catalogue can be utilized as a useful data set for hazard and risk assessment instead of short, incomplete and inhomogeneous available catalogues.

  9. Evidence for a twelfth large earthquake on the southern hayward fault in the past 1900 years (United States)

    Lienkaemper, J.J.; Williams, P.L.; Guilderson, T.P.


    We present age and stratigraphic evidence for an additional paleoearthquake at the Tyson Lagoon site. The acquisition of 19 additional radiocarbon dates and the inclusion of this additional event has resolved a large age discrepancy in our earlier earthquake chronology. The age of event E10 was previously poorly constrained, thus increasing the uncertainty in the mean recurrence interval (RI), a critical factor in seismic hazard evaluation. Reinspection of many trench logs revealed substantial evidence suggesting that an additional earthquake occurred between E10 and E9 within unit u45. Strata in older u45 are faulted in the main fault zone and overlain by scarp colluviums in two locations.We conclude that an additional surfacerupturing event (E9.5) occurred between E9 and E10. Since 91 A.D. (??40 yr, 1??), 11 paleoearthquakes preceded the M 6:8 earthquake in 1868, yielding a mean RI of 161 ?? 65 yr (1??, standard deviation of recurrence intervals). However, the standard error of the mean (SEM) is well determined at ??10 yr. Since ~1300 A.D., the mean rate has increased slightly, but is indistinguishable from the overall rate within the uncertainties. Recurrence for the 12-event sequence seems fairly regular: the coefficient of variation is 0.40, and it yields a 30-yr earthquake probability of 29%. The apparent regularity in timing implied by this earthquake chronology lends support for the use of time-dependent renewal models rather than assuming a random process to forecast earthquakes, at least for the southern Hayward fault.

  10. Comment on "Astronomical alignments as the cause of ~M6+ seismicity"

    CERN Document Server

    Zanette, Damian H


    It is shown that, according to the criteria used by M. Omerbashich (arXiv:1104.2036v4 [physics.gen-ph]), during 2010 the Earth was aligned with at least one pair of planets some 98.6% of the time. This firmly supports Omerbashich's claim that 2010 strongest earthquakes occurred during such astronomical alignments. On this basis, we argue that seismicity is, generally, a phenomenon of astrological origin.

  11. Earthquake damage to underground facilities

    Energy Technology Data Exchange (ETDEWEB)

    Pratt, H.R.; Hustrulid, W.A. Stephenson, D.E.


    The potential seismic risk for an underground nuclear waste repository will be one of the considerations in evaluating its ultimate location. However, the risk to subsurface facilities cannot be judged by applying intensity ratings derived from the surface effects of an earthquake. A literature review and analysis were performed to document the damage and non-damage due to earthquakes to underground facilities. Damage from earthquakes to tunnels, s, and wells and damage (rock bursts) from mining operations were investigated. Damage from documented nuclear events was also included in the study where applicable. There are very few data on damage in the subsurface due to earthquakes. This fact itself attests to the lessened effect of earthquakes in the subsurface because mines exist in areas where strong earthquakes have done extensive surface damage. More damage is reported in shallow tunnels near the surface than in deep mines. In mines and tunnels, large displacements occur primarily along pre-existing faults and fractures or at the surface entrance to these facilities.Data indicate vertical structures such as wells and shafts are less susceptible to damage than surface facilities. More analysis is required before seismic criteria can be formulated for the siting of a nuclear waste repository.

  12. Large earthquakes and creeping faults (United States)

    Harris, Ruth A.


    Faults are ubiquitous throughout the Earth's crust. The majority are silent for decades to centuries, until they suddenly rupture and produce earthquakes. With a focus on shallow continental active-tectonic regions, this paper reviews a subset of faults that have a different behavior. These unusual faults slowly creep for long periods of time and produce many small earthquakes. The presence of fault creep and the related microseismicity helps illuminate faults that might not otherwise be located in fine detail, but there is also the question of how creeping faults contribute to seismic hazard. It appears that well-recorded creeping fault earthquakes of up to magnitude 6.6 that have occurred in shallow continental regions produce similar fault-surface rupture areas and similar peak ground shaking as their locked fault counterparts of the same earthquake magnitude. The behavior of much larger earthquakes on shallow creeping continental faults is less well known, because there is a dearth of comprehensive observations. Computational simulations provide an opportunity to fill the gaps in our understanding, particularly of the dynamic processes that occur during large earthquake rupture and arrest.

  13. Locations and magnitudes of earthquakes in Central Asia from seismic intensity data (United States)

    Bindi, D.; Parolai, S.; Gómez-Capera, A.; Locati, M.; Kalmetyeva, Z.; Mikhailova, N.


    .e. the Aksu and Chon-Aksu segments), where most of the seismic moment was released (Arrowsmith et al. in Eos Trans Am Geophys Union 86(52), 2005). The second location is located on the westernmost sub-faults (i.e. the Dzhil'-Aryk segment), close to the intensity centre location obtained for the 1938, M 6.9 Chu-Kemin earthquake (MILH = 6.9 and MIW = 6.8).

  14. Seismic databases and earthquake catalogue of the Caucasus (United States)

    Godoladze, Tea; Javakhishvili, Zurab; Tvaradze, Nino; Tumanova, Nino; Jorjiashvili, Nato; Gok, Rengen


    The Caucasus has a documented historical catalog stretching back to the beginning of the Christian era. Most of the largest historical earthquakes prior to the 19th century are assumed to have occurred on active faults of the Greater Caucasus. Important earthquakes include the Samtskhe earthquake of 1283, Ms~7.0, Io=9; Lechkhumi-Svaneti earthquake of 1350, Ms~7.0, Io=9; and the Alaverdi(earthquake of 1742, Ms~6.8, Io=9. Two significant historical earthquakes that may have occurred within the Javakheti plateau in the Lesser Caucasus are the Tmogvi earthquake of 1088, Ms~6.5, Io=9 and the Akhalkalaki earthquake of 1899, Ms~6.3, Io =8-9. Large earthquakes that occurred in the Caucasus within the period of instrumental observation are: Gori 1920; Tabatskuri 1940; Chkhalta 1963; 1991 Ms=7.0 Racha earthquake, the largest event ever recorded in the region; the 1992 M=6.5 Barisakho earthquake; Ms=6.9 Spitak, Armenia earthquake (100 km south of Tbilisi), which killed over 50,000 people in Armenia. Recently, permanent broadband stations have been deployed across the region as part of various national networks (Georgia (~25 stations), Azerbaijan (~35 stations), Armenia (~14 stations)). The data from the last 10 years of observation provides an opportunity to perform modern, fundamental scientific investigations. A catalog of all instrumentally recorded earthquakes has been compiled by the IES (Institute of Earth Sciences, Ilia State University). The catalog consists of more then 80,000 events. Together with our colleagues from Armenia, Azerbaijan and Turkey the database for the Caucasus seismic events was compiled. We tried to improve locations of the events and calculate Moment magnitudes for the events more than magnitude 4 estimate in order to obtain unified magnitude catalogue of the region. The results will serve as the input for the Seismic hazard assessment for the region.

  15. Two models for earthquake forerunners (United States)

    Mjachkin, V.I.; Brace, W.F.; Sobolev, G.A.; Dieterich, J.H.


    Similar precursory phenomena have been observed before earthquakes in the United States, the Soviet Union, Japan, and China. Two quite different physical models are used to explain these phenomena. According to a model developed by US seismologists, the so-called dilatancy diffusion model, the earthquake occurs near maximum stress, following a period of dilatant crack expansion. Diffusion of water in and out of the dilatant volume is required to explain the recovery of seismic velocity before the earthquake. According to a model developed by Soviet scientists growth of cracks is also involved but diffusion of water in and out of the focal region is not required. With this model, the earthquake is assumed to occur during a period of falling stress and recovery of velocity here is due to crack closure as stress relaxes. In general, the dilatancy diffusion model gives a peaked precursor form, whereas the dry model gives a bay form, in which recovery is well under way before the earthquake. A number of field observations should help to distinguish between the two models: study of post-earthquake recovery, time variation of stress and pore pressure in the focal region, the occurrence of pre-existing faults, and any changes in direction of precursory phenomena during the anomalous period. ?? 1975 Birkha??user Verlag.

  16. Earthquake potential revealed by tidal influence on earthquake size-frequency statistics (United States)

    Ide, Satoshi; Yabe, Suguru; Tanaka, Yoshiyuki


    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.

  17. Hurricane Sandy and earthquakes




    Submit for consideration the connection between formation of a hurricane Sandy and earthquakes. As a rule, weather anomalies precede and accompany earthquakes. The hurricane Sandy emerged 2 days prior to strong earthquakes that occurred in the area. And the trajectory of the hurricane Sandy matched the epicenter of the earthquakes. Possibility of early prediction of natural disasters will minimize the moral and material damage.

  18. Observations of large earthquakes in the Mexican subduction zone over 110 years (United States)

    Hjörleifsdóttir, Vala; Krishna Singh, Shri; Martínez-Peláez, Liliana; Garza-Girón, Ricardo; Lund, Björn; Ji, Chen


    , without changes in the instrument response. Furthermore, it has a relatively short natural period and is at a 90 degree angle from the Mesoamerican trench, making it highly sensitive to lateral variations in location. In total we have registers from more than 20, M>6.9 earthquakes in seven along trench segments. Events in this region are known to have a relatively short and simple rupture history, which has been interpreted as compact isolated asperities breaking in each event (Stewart et al 1982). Due to their short duration we assume that in the period range of the Wiechert instrument they are practically point sources, and any differences in waveforms are due to differences in location. This is not true for the largest events, as well a small number of the intermediate sized earthquakes, but these events can be identified by their complex P-waves. Of the seven different along trench segments, the Ometepec segment, on the border between the states of Guerrero and Oaxaca, has the largest number of earthquakes during the time period, or a total of five. Of those, three have near-identical waveforms, which we interpret as a repeatedly breaking asperity. The central Oaxaca segment also has had two earthquakes with highly similar waveforms, indicating comparable rupture areas in the two events. In other areas we find that subsequent earthquakes breaking the same segment do not have similar waveforms, indicating that different areas of the fault surface break in each event, or in a few cases, a more complex rupture history. Our observations therefore indicate that both processes are important, perhaps with varying relative importance depending on the region. In other words, some asperities are persistent over time, whereas others are not.

  19. Correlation between subjective well-being and personality of patients with paraplegia caused by Tangshan Earthquake%唐山地震所致截瘫患者主观幸福感与人格特征相关研究

    Institute of Scientific and Technical Information of China (English)

    陈昕; 李亚军; 赵鹤亮; 赵轶


    Objective To investigate the subjective well-being (SWB) among the patients of paraplegia caused by Tangshan Earthquake and the relationship between the SWB and personality characteristics of the paraplegics. Methods The General Well-Being Schedule (GWB) and Eysenck Personality Questionnaire were used to survey 119 patients of paraplegia caused by Tangshan Earthquake, 52 males and 59 females, aged 48~89(61.14±8.34)], 35 years after the Tangshan Earthquake. Three months later they were surveyed once more with the same scales. Results ① The test-retest consistency was 0.85. ② The paraplegics showed significantly lower scores of health concern(t=-23.270,P <0.01)and emotion and behavior control(t=-13.166,P <0.01) , and significantly higher scores of depression or happy mood(t=3.678,P <0.001), and relaxation and tension (anxiety) (t=10.367,P <0.01). ③ Those with hobbies showed significantly higher scores in overall SWB sense, depression or happy mood, and relaxation and tension (anxiety) (P <0.05,P <0.01,and P <0.05). ④ The higher the income the paraplegics obtained the more sense of SWB (F=3.677,P <0.05). ⑤ The SWB of the paraplegics was negatively correlated with the extroversion(r=-0.230,P <0.05), neuroticism (r=-0.308,P <0.01), and psychoticism (r=-0.373,P <0.001) of the paraplegics. Conclusion Compared with the norms, the patients of paraplegia caused by earthquake show more anxiety and less concern about their health condition, and are more difficult to control their behavior and emotion. The higher the income the paraplegics obtain the more sense of SWB, and the higher the psychoticism and neuroticism scores the lower the sense of SWB.%目的:探讨唐山地震所致截瘫患者的主观幸福感及其与人格特征的关系。方法唐山地震35年后,采用主观幸福感量表(GWB)与艾森克人格问卷(EPQ)对111名唐山地震所致截瘫患者[男52人,女59人,48~89((61.14±8.34)岁]进行调查。3个月后出重新

  20. Investigations on Real-time GPS for Earthquake Early Warning (United States)

    Grapenthin, R.; Aranha, M. A.; Melgar, D.; Allen, R. M.


    The Geodetic Alarm System (G-larmS) is a software system developed in a collaboration between the Berkeley Seismological Laboratory (BSL) and New Mexico Tech (NMT) primarily for real-time Earthquake Early Warning (EEW). It currently uses high rate (1Hz), low latency (inversion on these offsets to determine slip on a finite fault, which we use to estimate moment magnitude. These computations are repeated every second for the duration of the event. G-larmS has been in continuous operation at the BSL for over a year using event triggers from the California Integrated Seismic Network (CISN) ShakeAlert system and real-time position time series from a fully triangulated network consisting of BARD, PBO and USGS stations across northern California. Pairs of stations are processed as baselines using trackRT (MIT software package). G-larmS produced good results in real-time during the South Napa (M 6.0, August 2014) earthquake as well as on several replayed and simulated test cases. We evaluate the performance of G-larmS for EEW by analysing the results using a set of well defined test cases to investigate the following: (1) using multiple fault regimes and concurrent processing with the ultimate goal of achieving model generation (slip and magnitude computations) within each 1 second GPS epoch on very large magnitude earthquakes (up to M 9.0), (2) the use of Precise Point Positioning (PPP) real-time data streams of various operators, accuracies, latencies and formats along with baseline data streams, (3) collaboratively expanding EEW coverage along the U.S. West Coast on a regional network basis for Northern California, Southern California and Cascadia.

  1. Study on Stress Triggering During the Activity Process of the Jiashi Strong Earthquake Swarm

    Institute of Scientific and Technical Information of China (English)


    The Bachu-Jiashi earthquake of Ms6.8 occurred on February 24, 2003, about 20km from the southeast of the 1997 ~ 1998 Jiashi seismic region in Xinjiang, and its aftershocks are rich and strong. Did the 1997 ~ 1998 Jiashi strong earthquake swarm trigger the Bachu-Jiashi Ms6.8earthquake? The Atushi earthquake of Ms6.7 occurred in 1996, and the 1997 ~ 1998 Jiashi strong earthquake swarm occurred about 70km from the Atushi earthquake 10 months later.Did the Atushi earthquake of Ms6.7 encourage the 1997 ~ 1998 Jiashi strong earthquake swarm? There were 9 earthquakes with Ms6.0 from 1996 to 1997 in the Jiashi seismic region,how did they act on each other? To answer the above questions, the article studies the triggering effect of the activity process of the whole Jiashi earthquake swarm from the 1996 Atushi earthquake of Ms6.7, the 1997 ~ 1998 Jiashi strong swarm to the 2003 Bachu-Jiashi earthquake of Ms6.8, and analyzes the seismicity characteristics around the Jiashi region. The results show that the 1996 Atushi earthquake of Ms6.7 encouraged the 1997 ~ 1998 Jiashi strong swarm to some extent, the accumulative Coulomb stress change from the previous M6.0earthquakes of the Jiashi strong swarm had certain triggering effects on the following M6.0 events, and the Coulomb stress change converted from the Jiashi strong swarm strongly encouraged the 2003 Bachu-Jiashi earthquake with Ms6.8.

  2. 感官释放 全新BMW M6

    Institute of Scientific and Technical Information of China (English)



    对于极致驾乘乐趣无止尽的热情与追求,一直是BMW集团最感荣耀的信念与使命。全新BMW M6的诞生,不仅传承BMW M1和635CSi的经典性能表现,并成功演绎大型豪华双门跑车6系列的优异设计,成为BMW当代M系列中最疾速的旗舰车款!

  3. Quantifying slip balance in the earthquake cycle: Coseismic slip model constrained by interseismic coupling

    KAUST Repository

    Wang, Lifeng


    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.

  4. Dynamics of liquefaction during the 1987 Superstition Hills, California, earthquake (United States)

    Holzer, T.L.; Youd, T.L.; Hanks, T.C.


    Simultaneous measurements of seismically induced pore-water pressure changes and surface and subsurface accelerations at a site undergoing liquefaction caused by the Superstition Hills, California, earthquake (24 November 1987; M = 6.6) reveal that total pore pressures approached lithostatic conditions, but, unexpectedly, after most of the strong motion ceased. Excess pore pressures were generated once horizontal acceleration exceeded a threshold value.


    Energy Technology Data Exchange (ETDEWEB)

    CHOU,W.; WEI,J.


    The M6 working group had more than 40 active participants (listed in Section 4). During the three weeks at Snowmass, there were about 50 presentations, covering a wide range of topics associated with high intensity proton sources. The talks are listed in Section 5. This group also had joint sessions with a number of other working groups, including E1 (Neutrino Factories and Muon Colliders), E5 (Fixed-Target Experiments), M1 (Muon Based Systems), T4 (Particle Sources), T5 (Beam dynamics), T7 (High Performance Computing) and T9 (Diagnostics). The M6 group performed a survey of the beam parameters of existing and proposed high intensity proton sources, in particular, of the proton drivers. The results are listed in Table 1. These parameters are compared with the requirements of high-energy physics users of secondary beams in Working Groups E1 and E5. According to the consensus reached in the E1 and E5 groups, the U.S. HEP program requires an intense proton source, a 1-4 MW Proton Driver, by the end of this decade.

  6. Re-examination of the original questionnaire documents for the 1944 Tonankai, 1945 Mikawa, and 1946 Nanaki earthquakes (United States)

    Harada, Tomoya; Satake, Kenji; Furumura, Takashi


    With the object of estimating seismic intensity, the Earthquakes Research Institute (ERI) of the University of Tokyo performed questionnaire surveys for the significant (destructive or large/great) earthquakes from 1943 to 1988 (Kayano, 1990, BERI). In these surveys, Kawasumi (1943)'s 12-class seismic intensity scale similar to the Modified Mercalli scale (MM-scale) was used. Survey results for earthquakes after 1950 were well investigated and published (e.g. Kayano and Komaki, 1977, BERI; Kayano and Sato, 1975, BERI), but the survey results for earthquakes in the 1940s have not been published and original documents of the surveys was missing. Recently, the original sheets of the surveys for the five earthquakes in the 1940s with more than 1,000 casualties were discovered in the ERI warehouse, although they are incomplete (Tsumura et al, 2010). They are from the 1943 Tottori (M 7.2), 1944 Tonankai (M 7.9), 1945 Mikawa (M 6.8), 1946 Nankai (M 8.0), and 1948 Fukui (M 7.1) earthquakes. In this study, we examined original questionnaire and summary sheets for the 1944 Tonankai, 1945 Mikawa, and 1946 Nanaki earthquakes, and estimated the distributions of seismic intensity, various kinds of damage, and human behaviors in detail. Numbers of the survey points for the 1944, 1945, and 1946 event are 287, 145, and 1,014, respectively. The numbers for the 1944 and 1945 earthquakes are much fewer than that of the 1946 event, because they occurred during the last years of World War II. The 1944 seismic intensities in the prefectures near the source region (Aichi, Mie, Shizuoka, and Gifu Pref.) tend to be high. However, the 1944 intensities are also high and damage is serious at the Suwa Lake shore in Nagano Pref. which is about 240 km far from the source region because seismic waves are amplified dramatically in the thick sediment in the Suwa Basin. Seismic intensities of the 1945 Mikawa earthquake near the source region in Aichi Pref. were very high (X-XI). However, the

  7. Tohoku earthquake: a surprise?

    CERN Document Server

    Kagan, Yan Y


    We consider three issues related to the 2011 Tohoku mega-earthquake: (1) how to evaluate the earthquake maximum size in subduction zones, (2) what is the repeat time for the largest earthquakes in Tohoku area, and (3) what are the possibilities of short-term forecasts during the 2011 sequence. There are two quantitative methods which can be applied to estimate the maximum earthquake size: a statistical analysis of the available earthquake record and the moment conservation principle. The latter technique studies how much of the tectonic deformation rate is released by earthquakes. For the subduction zones, the seismic or historical record is not sufficient to provide a reliable statistical measure of the maximum earthquake. The moment conservation principle yields consistent estimates of maximum earthquake size: for all the subduction zones the magnitude is of the order 9.0--9.7, and for major subduction zones the maximum earthquake size is statistically indistinguishable. Starting in 1999 we have carried out...

  8. Earthquake Source and Ground Motion Characteristics of Great Kanto Earthquakes (United States)

    Somerville, P. G.; Sato, T.; Wald, D. J.; Graves, R. W.; Dan, K.


    This paper describes the derivation of a rupture model of the 1923 Kanto earthquake, and the estimation of ground motions that occurred during that earthquake and that might occur during future great Kanto earthquakes. The rupture model was derived from the joint inversion of geodetic and teleseismic data. The leveling and triangulation data place strong constraints on the distribution and orientation of slip on the fault. The most concentrated slip is in the shallow central and western part of the fault. The location of the hypocenter on the western part of the fault gives rise to strong near fault rupture directivity effects, which are largest toward the east in the Boso Peninsula. To estimate the ground motions caused by this earthquake, we first calibrated 1D and 3D wave propagation path effects using the Odawara earthquake of 5 August 1990 (M 5.1), the first earthquake larger than M 5 in the last 60 years near the hypocenter of the 1923 Kanto earthquake. The simulation of the moderate-sized Odawara earthquake demonstrates that the 3D velocity model works quite well at reproducing the recorded long-period (T > 3.33 sec) strong motions, including basin-generated surface waves, for a number of sites located throughout the Kanto basin region. Using this validated 3D model along with the rupture model described above, we simulated the long-period (T > 4 sec) ground motions in this region for the 1923 Kanto earthquake. The largest ground motions occur east of the epicenter along the central and southern part of the Boso Peninsula. These large motions arise from strong rupture directivity effects and are comprised of relatively simple, source-controlled pulses with a dominant period of about 10 sec. Other rupture models and hypocenter locations generally produce smaller long period ground motion levels in this region that those of the 1923 event. North of the epicentral region, in the Tokyo area, 3D basin-generated phases are quite significant, and these phases

  9. Earthquake Potential in the Zagros Region, Iran

    Directory of Open Access Journals (Sweden)

    Madahizadeh Rohollah


    Full Text Available Seismic strain and b value are used to quantify seismic potential in the Zagros region (Iran. Small b values (0.69 and 0.69 are related to large seismic moment rates (9.96×1017 and 4.12×1017 in southern zones of the Zagros, indicating more frequent large earthquakes. Medium to large b values (0.72 and 0.92 are related to small seismic moment rates (2.94×1016 and 6.80×1016 in middle zones of the Zagros, indicating less frequent large earthquakes. Small b value (0.64 is related to medium seismic moment rate (1.38×1017 in middle to northern zone of the Zagros, indicating frequent large earthquakes. Large b value (0.87 is related to large seismic moment rate (2.29×1017 in northwestern zone, indicating more frequent large earthquakes. Recurrence intervals of large earthquakes (M > 6 are short in southern (10 and 14 years and northwestern (13 years zones, while the recurrence intervals are long in the middle (46 and 114 years and middle to northern (25 years zones.

  10. Receptor-mediated hepatic uptake of M6P-BSA-conjugated triplex-forming oligonucleotides in rats. (United States)

    Ye, Zhaoyang; Cheng, Kun; Guntaka, Ramareddy V; Mahato, Ram I


    Excessive production of extracellular matrix, predominantly type I collagen, results in liver fibrosis. Earlier we synthesized mannose 6-phosphate-bovine serum albumin (M6P-BSA) and conjugated to the type I collagen specific triplex-forming oligonucleotide (TFO) for its enhanced delivery to hepatic stellate cells (HSCs), which is the principal liver fibrogenic cell. In this report, we demonstrate a time-dependent cellular uptake of M6P-BSA-33P-TFO by HSC-T6 cells. Both cellular uptake and nuclear deposition of M6P-BSA-33P-TFO were significantly higher than those of 33P-TFO, leading to enhanced inhibition of type I collagen transcription. Following systemic administration into rats, hepatic accumulation of M6P-BSA-33P-TFO increased from 55% to 68% with the number of M6P per BSA from 14 to 27. Unlike 33P-TFO, there was no significant decrease in the hepatic uptake of (M6P)20-BSA-33P-TFO in fibrotic rats. Prior administration of excess M6P-BSA decreased the hepatic uptake of (M6P)20-BSA-33P-TFO from 66% to 40% in normal rats, and from 60% to 15% in fibrotic rats, suggesting M6P/insulin-like growth factor II (M6P/IGF II) receptor-mediated endocytosis of M6P-BSA-33P-TFO by HSCs. Almost 82% of the total liver uptake in fibrotic rats was contributed by HSCs. In conclusion, by conjugation with M6P-BSA, the TFO could be potentially used for the treatment of liver fibrosis.

  11. Characteristic earthquake model, 1884 -- 2011, R.I.P

    CERN Document Server

    Kagan, Yan Y; Geller, Robert J


    Unfortunately, working scientists sometimes reflexively continue to use "buzz phrases" grounded in once prevalent paradigms that have been subsequently refuted. This can impede both earthquake research and hazard mitigation. Well-worn seismological buzz phrases include "earthquake cycle," "seismic cycle," "seismic gap," and "characteristic earthquake." They all assume that there are sequences of earthquakes that are nearly identical except for the times of their occurrence. If so, the complex process of earthquake occurrence could be reduced to a description of one "characteristic" earthquake plus the times of the others in the sequence. A common additional assumption is that characteristic earthquakes dominate the displacement on fault or plate boundary "segments." The "seismic gap" (or the effectively equivalent "seismic cycle") model depends entirely on the "characteristic" assumption, with the added assumption that characteristic earthquakes are quasi-periodic. However, since the 1990s numerous statistica...

  12. Field reconnaissance of the 2007 Niigata-Chuetsu Oki earthquake

    Institute of Scientific and Technical Information of China (English)

    Georgios Apostolakis; Bing Qu; Nurhan Ecemis; Seda Dogruel


    As part of the 2007 Yri-Center Field Mission to Japan,a reconnaissance team comprised of fourteen graduate students and three faculty members from three U.S. earthquake engineering research centers,namely,Multidisciplinary Center for Earthquake Engineering Research (MCEER),Mid-America Earthquake Center(MAE),and Pacific Earthquake Engineering Research Center (PEER),undertook a reconnaissance visit to the affected area shortly after the 2007 NiigataChuetsu Oki earthquake.This mission provided an opportunity to review the nature of the earthquake damage that occurred,as well as to assess the significance of the damage from an educational perspective.This paper reports on the seismological characteristics of the earthquake,preliminary findings of geotechnical and structural damage,and the causes of the observed failures or collapses.In addition,economic and socio-economic considerations and experiences to enhance earthquake resilience are presented.

  13. Field reconnaissance of the 2007 Niigata-Chuetsu Oki earthquake (United States)

    Apostolakis, Georgios; Qu, Bing; Ecemis, Nurhan; Dogruel, Seda


    As part of the 2007 Tri-Center Field Mission to Japan, a reconnaissance team comprised of fourteen graduate students and three faculty members from three U.S. earthquake engineering research centers, namely, Multidisciplinary Center for Earthquake Engineering Research (MCEER), Mid-America Earthquake Center (MAE), and Pacific Earthquake Engineering Research Center (PEER), undertook a reconnaissance visit to the affected area shortly after the 2007 Niigata-Chuetsu Oki earthquake. This mission provided an opportunity to review the nature of the earthquake damage that occurred, as well as to assess the significance of the damage from an educational perspective. This paper reports on the seismological characteristics of the earthquake, preliminary findings of geotechnical and structural damage, and the causes of the observed failures or collapses. In addition, economic and socio-economic considerations and experiences to enhance earthquake resilience are presented.

  14. 3D Dynamic Rupture Simulations Across Interacting Faults: the Mw7.0, 2010, Haiti Earthquake (United States)

    Douilly, R.; Aochi, H.; Calais, E.; Freed, A. M.; Aagaard, B.


    The mechanisms controlling rupture propagation between fault segments during an earthquake are key to the hazard posed by fault systems. Rupture initiation on a fault segment sometimes transfers to a larger fault, resulting in a significant event (e.g.i, 2002 M7.9Denali and 2010 M7.1 Darfield earthquakes). In other cases rupture is constrained to the initial segment and does not transfer to nearby faults, resulting in events of moderate magnitude. This is the case of the 1989 M6.9 Loma Prieta and 2010 M7.0 Haiti earthquakes which initiated on reverse faults abutting against a major strike-slip plate boundary fault but did not propagate onto it. Here we investigatethe rupture dynamics of the Haiti earthquake, seeking to understand why rupture propagated across two segments of the Léogâne fault but did not propagate to the adjacenent Enriquillo Plantain Garden Fault, the major 200 km long plate boundary fault cutting through southern Haiti. We use a Finite Element Model to simulate the nucleation and propagation of rupture on the Léogâne fault, varying friction and background stress to determine the parameter set that best explains the observed earthquake sequence. The best-fit simulation is in remarkable agreement with several finite fault inversions and predicts ground displacement in very good agreement with geodetic and geological observations. The two slip patches inferred from finite-fault inversions are explained by the successive rupture of two fault segments oriented favorably with respect to the rupture propagation, while the geometry of the Enriquillo fault did not allow shear stress to reach failure. Although our simulation results replicate well the ground deformation consistent with the geodetic surface observation but convolving the ground motion with the soil amplification from the microzonation study will correctly account for the heterogeneity of the PGA throughout the rupture area.

  15. Acute guttate psoriasis patients have positive streptococcus hemolyticus throat cultures and elevated antistreptococcal M6 protein titers. (United States)

    Zhao, Guang; Feng, Xiaoling; Na, Aihua; Yongqiang, Jiang; Cai, Qing; Kong, Jian; Ma, Huijun


    To further study the role of Streptococci hemolyticus infection and streptococcal M6 protein in the pathogenesis of acute guttate psoriasis, streptococcal cultures were taken from the throats of 68 patients with acute guttate psoriasis. PCR technique was applied to detect M6 protein encoding DNA from those cultured streptococci. Pure M6 protein was obtained by Sephacry/S-200HR and Mono-Q chromatography from proliferated Streptococcus hemolyticus. Antistreptococcal M6 protein titers were measured in the serum of patients with acute guttate psoriasis, plaque psoriasis and healthy controls by ELISA. A high incidence of Streptococcus hemolyticus culture was observed in the guttate psoriatic group compared with the plaque psoriasis and control groups. Fourteen strains of Streptococcus hemolyticus were cultured from the throats of 68 acute guttate psoriasis patients. Of these, 5 strains contain DNA encoding the M6 protein gene as confirmed by PCR technique. More than 85% purification of M6 protein was obtained from Streptococcus pyogenes. Applying our pure M6 protein with the ELISA methods, we found that the titer of antistreptococcal M6 protein was significantly higher in the serum of guttate psoriasis patients than in the control or plaque psoriasis groups (P psoriasis have a high incidence of Streptococcus hemolyticus in their throats and raised titers of antistreptococcal M6 protein in their sera.

  16. Using earthquake intensities to forecast earthquake occurrence times

    Directory of Open Access Journals (Sweden)

    J. R. Holliday


    Full Text Available It is well known that earthquakes do not occur randomly in space and time. Foreshocks, aftershocks, precursory activation, and quiescence are just some of the patterns recognized by seismologists. Using the Pattern Informatics technique along with relative intensity analysis, we create a scoring method based on time dependent relative operating characteristic diagrams and show that the occurrences of large earthquakes in California correlate with time intervals where fluctuations in small earthquakes are suppressed relative to the long term average. We estimate a probability of less than 1% that this coincidence is due to random clustering. Furthermore, we show that the methods used to obtain these results may be applicable to other parts of the world.

  17. Uniform California earthquake rupture forecast, version 2 (UCERF 2) (United States)

    Field, E.H.; Dawson, T.E.; Felzer, K.R.; Frankel, A.D.; Gupta, V.; Jordan, T.H.; Parsons, T.; Petersen, M.D.; Stein, R.S.; Weldon, R.J.; Wills, C.J.


    The 2007 Working Group on California Earthquake Probabilities (WGCEP, 2007) presents the Uniform California Earthquake Rupture Forecast, Version 2 (UCERF 2). This model comprises a time-independent (Poisson-process) earthquake rate model, developed jointly with the National Seismic Hazard Mapping Program and a time-dependent earthquake-probability model, based on recent earthquake rates and stress-renewal statistics conditioned on the date of last event. The models were developed from updated statewide earthquake catalogs and fault deformation databases using a uniform methodology across all regions and implemented in the modular, extensible Open Seismic Hazard Analysis framework. The rate model satisfies integrating measures of deformation across the plate-boundary zone and is consistent with historical seismicity data. An overprediction of earthquake rates found at intermediate magnitudes (6.5 ??? M ???7.0) in previous models has been reduced to within the 95% confidence bounds of the historical earthquake catalog. A logic tree with 480 branches represents the epistemic uncertainties of the full time-dependent model. The mean UCERF 2 time-dependent probability of one or more M ???6.7 earthquakes in the California region during the next 30 yr is 99.7%; this probability decreases to 46% for M ???7.5 and to 4.5% for M ???8.0. These probabilities do not include the Cascadia subduction zone, largely north of California, for which the estimated 30 yr, M ???8.0 time-dependent probability is 10%. The M ???6.7 probabilities on major strike-slip faults are consistent with the WGCEP (2003) study in the San Francisco Bay Area and the WGCEP (1995) study in southern California, except for significantly lower estimates along the San Jacinto and Elsinore faults, owing to provisions for larger multisegment ruptures. Important model limitations are discussed.

  18. Scaling relation for earthquake networks

    CERN Document Server

    Abe, Sumiyoshi


    The scaling relation derived by Dorogovtsev, Goltsev, Mendes and Samukhin [Phys. Rev. E, 68 (2003) 046109] states that the exponents of the power-law connectivity distribution, gamma, and the power-law eigenvalue distribution of the adjacency matrix, delta, of a locally treelike scale-free network satisfy 2*gamma - delta = 1 in the mean field approximation. Here, it is shown that this relation holds well for the reduced simple earthquake networks (without tadpole-loops and multiple edges) constructed from the seismic data taken from California and Japan. The result is interpreted from the viewpoint of the hierarchical organization of the earthquake networks.

  19. Integrated Seismicity Model to Detect Pairs of Possible Interdependent Earthquakes and Its Application to Aftershocks of the 2011 Tohoku-Oki Earthquake and Sequence of the 2014 Kermadec and Rat Islands Earthquakes (United States)

    Miyazawa, M.; Tamura, R.


    We introduce an integrated seismicity model to stochastically evaluate the time intervals of consecutive earthquakes at global scales, making it possible to detect a pair of earthquakes that are remotely located and possibly related to each other. The model includes seismicity in non-overlapping areas and comprehensively explains the seismicity on the basis of point process models, which include the stationary Poisson model, the aftershock decay model following Omori-Utsu's law, and/or the epidemic-type aftershock sequence (ETAS) model. By use of this model, we examine the possibility of remote triggering of the 2011 M6.4 eastern Shizuoka earthquake in the vicinity of Mt. Fuji that occurred 4 days after the Mw9.0 Tohoku-Oki earthquake and 4 minutes after the M6.2 off-Fukushima earthquake that located about 400 km away, and that of the 2014 Mw7.9 Rat Islands earthquake that occurred within one hour after the Mw6.7 Kermadec earthquake that located about 9,000 km away and followed two large (Mw6.9, 6.5) earthquakes in the region. Both target earthquakes occurred during the passage of surface waves propagating from the previous large events. We estimated probability that the time interval is shorter than that between consecutive events and obtained dynamic stress changes on the faults. The results indicate that the M6.4 eastern Shizuoka event may be rather triggered by the static stress changes from the Tohoku-Oki earthquake and that the Mw7.9 Rat Islands event may have been remotely triggered by the Kermadec events possibly via cyclic fatigue.

  20. Earthquake rate and magnitude distributions of great earthquakes for use in global forecasts (United States)

    Kagan, Yan Y.; Jackson, David D.


    We have obtained new results in the statistical analysis of global earthquake catalogues with special attention to the largest earthquakes, and we examined the statistical behaviour of earthquake rate variations. These results can serve as an input for updating our recent earthquake forecast, known as the `Global Earthquake Activity Rate 1' model (GEAR1), which is based on past earthquakes and geodetic strain rates. The GEAR1 forecast is expressed as the rate density of all earthquakes above magnitude 5.8 within 70 km of sea level everywhere on earth at 0.1 × 0.1 degree resolution, and it is currently being tested by the Collaboratory for Study of Earthquake Predictability. The seismic component of the present model is based on a smoothed version of the Global Centroid Moment Tensor (GCMT) catalogue from 1977 through 2013. The tectonic component is based on the Global Strain Rate Map, a `General Earthquake Model' (GEM) product. The forecast was optimized to fit the GCMT data from 2005 through 2012, but it also fit well the earthquake locations from 1918 to 1976 reported in the International Seismological Centre-Global Earthquake Model (ISC-GEM) global catalogue of instrumental and pre-instrumental magnitude determinations. We have improved the recent forecast by optimizing the treatment of larger magnitudes and including a longer duration (1918-2011) ISC-GEM catalogue of large earthquakes to estimate smoothed seismicity. We revised our estimates of upper magnitude limits, described as corner magnitudes, based on the massive earthquakes since 2004 and the seismic moment conservation principle. The new corner magnitude estimates are somewhat larger than but consistent with our previous estimates. For major subduction zones we find the best estimates of corner magnitude to be in the range 8.9 to 9.6 and consistent with a uniform average of 9.35. Statistical estimates tend to grow with time as larger earthquakes occur. However, by using the moment conservation

  1. Membrane glycoprotein M6A promotes μ-opioid receptor endocytosis and facilitates receptor sorting into the recycling pathway

    Institute of Scientific and Technical Information of China (English)

    Ying-Jian Liang; Dai-Fei Wu; Ralf Stumm; Volker H(o)llt; Thomas Koch


    The interaction of μ-opioid receptor (MOPr) with the neuronal membrane glycoprotein M6a is known to facilitate MOPr endocytosis in human embryonic kidney 293 (HEK293) cells. To further study the role of M6a in the post-endocytotic sorting of MOPr, we investigated the agonist-induced co-internalization of MOPr and M6a and protein targeting after internalization in HEK293 cells that co-expressed HA-tagged MOPr and Myc-tagged M6a. We found that M6a, MOPr, and Rab 11, a marker for recycling endosomes, co-localized in endocytotic vesicles, indicating that MOPr and M6a are primarily targeted to recycling endosomes after endocytosis. Furthermore, co-expression of M6a augmented the post-endocytotic sorting of δ-opioid receptors into the recycling pathway, indicating that M6a might have a more general role in opioid receptor post-ndocytotic sorting. The enhanced post-endocytotic sorting of MOPr into the recycling pathway was accompanied by a decrease in agonist-induced receptor down-regulation of M6a in co-expressing cells. We tested the physiological relevance of these findings in primary cultures of cortical neurons and found that co-expression of M6a markedly increased the translocation of MOPrs from the plasma membrane to intracellular vesicles at steady state and significantly enhanced both constitutive and agonist-induced receptor endocytosis. In conclusion, our results strongly indicate that M6a modulates MOPr endocytosis and post-endocytotic sorting and has an important role in receptor regulation.

  2. Remotely triggered earthquakes following moderate main shocks (United States)

    Hough, S.E.


    Since 1992, remotely triggered earthquakes have been identified following large (M > 7) earthquakes in California as well as in other regions. These events, which occur at much greater distances than classic aftershocks, occur predominantly in active geothermal or volcanic regions, leading to theories that the earthquakes are triggered when passing seismic waves cause disruptions in magmatic or other fluid systems. In this paper, I focus on observations of remotely triggered earthquakes following moderate main shocks in diverse tectonic settings. I summarize evidence that remotely triggered earthquakes occur commonly in mid-continent and collisional zones. This evidence is derived from analysis of both historic earthquake sequences and from instrumentally recorded M5-6 earthquakes in eastern Canada. The latter analysis suggests that, while remotely triggered earthquakes do not occur pervasively following moderate earthquakes in eastern North America, a low level of triggering often does occur at distances beyond conventional aftershock zones. The inferred triggered events occur at the distances at which SmS waves are known to significantly increase ground motions. A similar result was found for 28 recent M5.3-7.1 earthquakes in California. In California, seismicity is found to increase on average to a distance of at least 200 km following moderate main shocks. This supports the conclusion that, even at distances of ???100 km, dynamic stress changes control the occurrence of triggered events. There are two explanations that can account for the occurrence of remotely triggered earthquakes in intraplate settings: (1) they occur at local zones of weakness, or (2) they occur in zones of local stress concentration. ?? 2007 The Geological Society of America.

  3. ElarmS Earthquake Early Warning System Updates and Performance (United States)

    Chung, A. I.; Allen, R. M.; Hellweg, M.; Henson, I. H.; Neuhauser, D. S.


    The ElarmS earthquake early warning algorithm has been detecting earthquakes throughout California since 2007. It is one of the algorithms that contributes to CISN's ShakeAlert, a prototype earthquake early warning system being developed for California. Overall, ElarmS performance has been excellent. Over the past year (July 1, 2014 - July 1, 2015), ElarmS successfully detected all but three of the significant earthquakes (M4+) that occurred within California. Of the 24 events that were detected, the most notable was the M6.0 South Napa earthquake that occurred on August 24, 2014. The first alert for this event was sent in 5.1 seconds with an initial magnitude estimate of M5.7. This alert provided approximately 8 seconds of warning of the impending S-wave arrival to the city of San Francisco. The magnitude estimate increased to the final value of M6.0 within 15 seconds of the initial alert. One of the two events that were not detected by ElarmS occurred within 30 seconds of the M6.0 Napa mainshock. The two other missed events occurred offshore in a region with sparse station coverage in the Eureka area. Since its inception, ElarmS has evolved and adapted to meet new challenges. On May 30, 2015, an extraordinarily deep (678km) M7.8 teleseism in Japan generated 5 false event detections for earthquakes greater than M4 within a minute due to the simultaneous arrival of the P-waves at stations throughout California. In order to improve the speed and accuracy of the ElarmS detections, we are currently exploring new methodologies to quickly evaluate incoming triggers from individual stations. Rapidly determining whether or not a trigger at a given station is due to a local earthquake or some other source (such as a distant teleseism) could dramatically increase the confidence in individual triggers and reduce false alerts.

  4. Earthquake Damage - General (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — An earthquake is the motion or trembling of the ground produced by sudden displacement of rock in the Earth's crust. Earthquakes result from crustal strain,...

  5. Earthquake Notification Service (United States)

    U.S. Geological Survey, Department of the Interior — The Earthquake Notification Service (ENS) is a free service that sends you automated notifications to your email or cell phone when earthquakes happen.

  6. Earthquakes: hydrogeochemical precursors (United States)

    Ingebritsen, Steven E.; Manga, Michael


    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.

  7. Earthquakes in Southern California (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — There have been many earthquake occurrences in Southern California. This set of slides shows earthquake damage from the following events: Imperial Valley, 1979,...

  8. Parallelization of the Coupled Earthquake Model (United States)

    Block, Gary; Li, P. Peggy; Song, Yuhe T.


    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.


    Institute of Scientific and Technical Information of China (English)



    Two measures of earthquakes, the seismic moment and the broadband radiated energy, show completely different scaling relations. For shallow earthquakes worldwide from January 1987 to December 1998, the frequency distribution of the seismic moment shows a clear kink between moderate and large earthquakes, as revealed by previous works. But the frequency distribution of the broadband radiated energy shows a single power law, a classical Gutenberg-Richter relation. This inconsistency raises a paradox in the self-organized criticality model of earthquakes.

  10. Triggering of repeating earthquakes in central California (United States)

    Wu, Chunquan; Gomberg, Joan; Ben-Naim, Eli; Johnson, Paul


    Dynamic stresses carried by transient seismic waves have been found capable of triggering earthquakes instantly in various tectonic settings. Delayed triggering may be even more common, but the mechanisms are not well understood. Catalogs of repeating earthquakes, earthquakes that recur repeatedly at the same location, provide ideal data sets to test the effects of transient dynamic perturbations on the timing of earthquake occurrence. Here we employ a catalog of 165 families containing ~2500 total repeating earthquakes to test whether dynamic perturbations from local, regional, and teleseismic earthquakes change recurrence intervals. The distance to the earthquake generating the perturbing waves is a proxy for the relative potential contributions of static and dynamic deformations, because static deformations decay more rapidly with distance. Clear changes followed the nearby 2004 Mw6 Parkfield earthquake, so we study only repeaters prior to its origin time. We apply a Monte Carlo approach to compare the observed number of shortened recurrence intervals following dynamic perturbations with the distribution of this number estimated for randomized perturbation times. We examine the comparison for a series of dynamic stress peak amplitude and distance thresholds. The results suggest a weak correlation between dynamic perturbations in excess of ~20 kPa and shortened recurrence intervals, for both nearby and remote perturbations.

  11. Napa Earthquake impact on water systems (United States)

    Wang, J.


    South Napa earthquake occurred in Napa, California on August 24 at 3am, local time, and the magnitude is 6.0. The earthquake was the largest in SF Bay Area since the 1989 Loma Prieta earthquake. Economic loss topped $ 1 billion. Wine makers cleaning up and estimated the damage on tourism. Around 15,000 cases of lovely cabernet were pouring into the garden at the Hess Collection. Earthquake potentially raise water pollution risks, could cause water crisis. CA suffered water shortage recent years, and it could be helpful on how to prevent underground/surface water pollution from earthquake. This research gives a clear view on drinking water system in CA, pollution on river systems, as well as estimation on earthquake impact on water supply. The Sacramento-San Joaquin River delta (close to Napa), is the center of the state's water distribution system, delivering fresh water to more than 25 million residents and 3 million acres of farmland. Delta water conveyed through a network of levees is crucial to Southern California. The drought has significantly curtailed water export, and salt water intrusion reduced fresh water outflows. Strong shaking from a nearby earthquake can cause saturated, loose, sandy soils liquefaction, and could potentially damage major delta levee systems near Napa. Napa earthquake is a wake-up call for Southern California. It could potentially damage freshwater supply system.

  12. Deformation in the central Gulf of California from the August 2009 M 6.9 event (United States)

    Plattner, C.; Amelung, F.; Malservisi, R.; Hackl, M.; Gonzalez-Garcia, J. J.


    The Gulf of California (GOC) hosts 90% of the Pacific - North America plate motion (thus about 45 mm/yr) along a transtensional fault system. In the central GOC, the major part of this deformation is localized at the Ballenas Transform fault segment, which is located at a narrow (~ 20 km wide) oceanic channel between the Baja California peninsula and Isla Angel de la Guarda. In August 2009 a Mw 6.9 earthquake occurred at this fault and lead to significant surface deformation that can be quantified from space geodetic data at Baja California peninsula and Isla Angel de la Guarda. Here we use a combination of Interferometric Satellite Aperture Radar (InSAR) data acquired by Envisat (May - November 2009) and campaign Global Positioning System (GPS) data (with data in May and December 2009). At the location of three of our five GPS sites we find excellent agreement between the InSAR and GPS data. At Isla Angel de la Guarda we test for phase ambiguity from unwrapping errors in the InSAR data, however these cannot explain the misfit between the InSAR and GPS data. We include the phase ambiguity testing into the elastic halfspace coseismic displacement modeling and invert for the fault parameters.

  13. Children's Ideas about Earthquakes (United States)

    Simsek, Canan Lacin


    Earthquake, a natural disaster, is among the fundamental problems of many countries. If people know how to protect themselves from earthquake and arrange their life styles in compliance with this, damage they will suffer will reduce to that extent. In particular, a good training regarding earthquake to be received in primary schools is considered…

  14. Earthquake and Schools. [Videotape]. (United States)

    Federal Emergency Management Agency, Washington, DC.

    Designing schools to make them more earthquake resistant and protect children from the catastrophic collapse of the school building is discussed in this videotape. It reveals that 44 of the 50 U.S. states are vulnerable to earthquake, but most schools are structurally unprepared to take on the stresses that earthquakes exert. The cost to the…

  15. School Safety and Earthquakes. (United States)

    Dwelley, Laura; Tucker, Brian; Fernandez, Jeanette


    A recent assessment of earthquake risk to Quito, Ecuador, concluded that many of its public schools are vulnerable to collapse during major earthquakes. A subsequent examination of 60 buildings identified 15 high-risk buildings. These schools were retrofitted to meet standards that would prevent injury even during Quito's largest earthquakes. US…

  16. Redefining Earthquakes and the Earthquake Machine (United States)

    Hubenthal, Michael; Braile, Larry; Taber, John


    The Earthquake Machine (EML), a mechanical model of stick-slip fault systems, can increase student engagement and facilitate opportunities to participate in the scientific process. This article introduces the EML model and an activity that challenges ninth-grade students' misconceptions about earthquakes. The activity emphasizes the role of models…

  17. Redefining Earthquakes and the Earthquake Machine (United States)

    Hubenthal, Michael; Braile, Larry; Taber, John


    The Earthquake Machine (EML), a mechanical model of stick-slip fault systems, can increase student engagement and facilitate opportunities to participate in the scientific process. This article introduces the EML model and an activity that challenges ninth-grade students' misconceptions about earthquakes. The activity emphasizes the role of models…

  18. Space Geodetic Imaging of Earthquake Potential in the San Francisco Bay Area (United States)

    Bürgmann, R.; Funning, G. J.; Ferretti, A.; Novali, F.


    Active crustal deformation in the San Francisco Bay Area includes contributions from elastic strain buildup across major faults and aseismic fault creep relieving a small portion of the plate tectonic fault slip budget. Increasingly precise and dense measurements of surface motions using GPS and InSAR satellite data provide valuable information on the distribution and rates of surface deformation. In the Eastern Bay Area, the Hayward, Calaveras and Concord faults are known to be source areas of moderate to large earthquakes, but also exhibit significant aseismic fault creep. Modeling of space geodetic data collected along the Hayward fault over > 10-year period allows for the determination of the distribution of currently locked asperities and creeping portions of the fault zone. Inversions of these data reveal a locked zone at depth which has built up a slip deficit since the 1868 Hayward fault rupture that is large enough to produce a M > 6.7 earthquake. The inferred slip rates along the creeping portions of the Hayward fault are significantly less than the long-term slip rate, and thus a substantial slip deficit is accumulating there as well. However, it is possible that the creeping portions of the East Bay faults will catch up most of their slip deficit by accelerated postseismic creep following large ruptures of the currently locked asperities. The kinematic locking models help inform dynamic rupture scenarios and ground motion simulations of major earthquakes along the Hayward fault (Aagaard et al., 2008 Fall AGU).

  19. Are "uncharacteristic" earthquakes spatially linked to strike-slip restraining bends? (United States)

    Mann, P.


    On the basis of a compilation of paleoseismological data from the Wasatch and San Andreas faults, Schwartz and Coppersmith (1984) proposed that both plate boundary and intraplate faults tend to generate essentially same size earthquakes having a relatively narrow range of magnitudes near the maximum. They referred to these earthquakes as "characteristic earthquakes". Their hypothesis suggests that the historical record of earthquakes documented for periods of time ranging from centuries to millennia in different parts of the world that could allow predictions of future ruptures. The characteristic earthquake model works surprisingly well for major strike-slip faults like the North Anatolian fault of Turkey and the North Tabriz strike-slip fault in Iran which both show a progressive, uni-direction pattern of rupture starting at one point and "unzippering" over a distance of hundreds of kilometers in a series of earthquakes. This regular periodicity has been attributed to systematic changes in Coulomb failure stress on individual faults or interconnected fault networks defined by distinctive changes in fault strike, or stepover faults, or by the intersection of a neighboring fault. However, studies of the San Andreas, Wasatch, and Dead Sea faults show that earthquake ruptures are not periodic and instead form clusters of events with no obvious "recurrence interval" as predicted by the characteristic earthquake model. Some of these hard-to-forecast "uncharacteristic" earthquakes initiate as blind thrust faults formed at deeper levels in the crust near the brittle-plastic transition zone as illustrated by the 1989 M 6.9 Loma Prieta earthquake of California. Such events would produce little or no surface rupture of the main fault plane so the effects of this type of earthquake would remain impossible for future paleoseismologists to discern (other than from shaking effects and the broad vertical uplift related to vertical motions on deeply buried faults). More recently

  20. Earthquake mechanism and seafloor deformation for tsunami generation (United States)

    Geist, Eric L.; Oglesby, David D.; Beer, Michael; Kougioumtzoglou, Ioannis A.; Patelli, Edoardo; Siu-Kui Au, Ivan


    Tsunamis are generated in the ocean by rapidly displacing the entire water column over a significant area. The potential energy resulting from this disturbance is balanced with the kinetic energy of the waves during propagation. Only a handful of submarine geologic phenomena can generate tsunamis: large-magnitude earthquakes, large landslides, and volcanic processes. Asteroid and subaerial landslide impacts can generate tsunami waves from above the water. Earthquakes are by far the most common generator of tsunamis. Generally, earthquakes greater than magnitude (M) 6.5–7 can generate tsunamis if they occur beneath an ocean and if they result in predominantly vertical displacement. One of the greatest uncertainties in both deterministic and probabilistic hazard assessments of tsunamis is computing seafloor deformation for earthquakes of a given magnitude.

  1. He I D3 Observation of the 1984 May 22 M6.3 Solar Flare

    CERN Document Server

    Liu, Chang; Deng, Na; Lee, Jeongwoo; Zhang, Jifeng; Choudhary, Debi Prasad; Wang, Haimin


    He I D3 line has a unique response to the flare impact on the low solar atmosphere and can be a powerful diagnostic tool for energy transport processes. Using images obtained from the recently digitized films of Big Bear Solar Observatory, we report D3 observation of the M6.3 flare on 1984 May 22, which occurred in an active region with a circular magnetic polarity inversion line (PIL). The impulsive phase of the flare starts with a main elongated source that darkens in D3, inside of which bright emission kernels appear at the time of the initial small peak in hard X-rays (HXRs). These flare cores subsequently evolve into a sharp emission strand lying within the dark halo simultaneously with the main peak in HXRs, reversing the overall source contrast from -5% to 5%. The radiated energy in D3 during the main peak is estimated to be about 10^30 ergs, which is comparable to that carried by nonthermal electrons above 20 keV. Afterwards the flare proceeds along the circular PIL in the counterclockwise direction t...

  2. Accuracy of an unstructured-grid upwind-Euler algorithm for the ONERA M6 wing (United States)

    Batina, John T.


    Improved algorithms for the solution of the three-dimensional, time-dependent Euler equations are presented for aerodynamic analysis involving unstructured dynamic meshes. The improvements have been developed recently to the spatial and temporal discretizations used by unstructured-grid flow solvers. The spatial discretization involves a flux-split approach that is naturally dissipative and captures shock waves sharply with at most one grid point within the shock structure. The temporal discretization involves either an explicit time-integration scheme using a multistage Runge-Kutta procedure or an implicit time-integration scheme using a Gauss-Seidel relaxation procedure, which is computationally efficient for either steady or unsteady flow problems. With the implicit Gauss-Seidel procedure, very large time steps may be used for rapid convergence to steady state, and the step size for unsteady cases may be selected for temporal accuracy rather than for numerical stability. Steady flow results are presented for both the NACA 0012 airfoil and the Office National d'Etudes et de Recherches Aerospatiales M6 wing to demonstrate applications of the new Euler solvers. The paper presents a description of the Euler solvers along with results and comparisons that assess the capability.

  3. Chemical composition of intermediate mass stars members of the M6 (NGC 6405) open cluster

    CERN Document Server

    Kılıçoğlu, Tolgahan; Richer, Jacques; Fossati, Luca; Albayrak, Berahitdin


    We present here the first abundance analysis of 44 late B, A and F-type members of the young open cluster M6 (NGC 6405, age about 75 Myrs). Spectra, covering the 4500 to 5800 \\AA{} wavelength range, were obtained using the FLAMES/GIRAFFE spectrograph attached to the ESO Very Large Telescopes (VLT). We determined the atmospheric parameters using calibrations of the Geneva photometry and by adjusting the $H_{\\beta}$ profiles to synthetic ones. The abundances of up to 20 chemical elements, were derived for 19 late B, 16 A and 9 F stars by iteratively adjusting synthetic spectra to the observations. We also derived a mean cluster metallicity of $\\mathrm{[Fe/H]=0.07\\pm0.03}$ dex from the iron abundances of the F-type stars. We find that, for most chemical elements, the normal late B and A-type stars exhibit larger star-to-star abundance variations than the F-type stars do probably because of the faster rotation of the B and A stars. The abundances of C, O, Mg, Si and Sc appear to be anticorrelated to that of Fe, w...

  4. Source Parameters for Repeating Earthquakes along the Middle America Trench (United States)

    Bilek, S. L.; Phillips, W. S.; Walter, J. I.; Peng, Z.; Schwartz, S. Y.; Brudzinski, M. R.; Yao, D.


    Repeating earthquakes, with their similar locations and similar waveforms, are often thought to represent slip along the same patch of fault. Analysis of these earthquake clusters can provide useful information about the nature of the fault and earthquake interaction. Here we focus on sequences of repeating earthquakes along both the Nicoya Peninsula, Costa Rica and along the Oaxaca segment of Mexico, as both megathrust faults have been well instrumented in recent years with local seismic networks able to record the small magnitude earthquakes. These regions have also experienced large megathrust earthquakes as well as non-volcanic tremor and slow slip, suggesting a complex fault system that allows a wide spectrum of slip. We can use source characteristics of the repeating earthquakes to probe this fault complexity. Along the Nicoya Peninsula, there are over 370 repeating earthquakes (M 0.5-3.3) in the 3 months following the 2012 Mw 7.6 megathrust earthquake grouped into 55 distinct clusters. Along Oaxaca, the earthquake clusters or swarms (M 1.5-5.5) span a wider spatial and temporal range. For our source parameter calculations, we form narrow-frequency band envelopes for pairs of earthquakes within the earthquake clusters to compute spectral ratios for each pair. We determine seismic moment, corner frequency, and earthquake stress drop for each earthquake from these spectral ratios. We compare the source parameters for events within the clusters to examine temporal variations and compare between clusters to explore spatial variations that could be linked to other slip heterogeneity. Preliminary results for the Nicoya region suggest nearly identical stress drop for repeating events within clusters located near the 2012 mainshock, and more variability in stress drops for earthquakes in clusters located updip and to the northwest of the mainshock.

  5. Earthquake outlook for the San Francisco Bay region 2014–2043 (United States)

    Aagaard, Brad T.; Blair, James Luke; Boatwright, John; Garcia, Susan H.; Harris, Ruth A.; Michael, Andrew J.; Schwartz, David P.; DiLeo, Jeanne S.; Jacques, Kate; Donlin, Carolyn


    Using information from recent earthquakes, improved mapping of active faults, and a new model for estimating earthquake probabilities, the 2014 Working Group on California Earthquake Probabilities updated the 30-year earthquake forecast for California. They concluded that there is a 72 percent probability (or likelihood) of at least one earthquake of magnitude 6.7 or greater striking somewhere in the San Francisco Bay region before 2043. Earthquakes this large are capable of causing widespread damage; therefore, communities in the region should take simple steps to help reduce injuries, damage, and disruption, as well as accelerate recovery from these earthquakes.

  6. Earthquake Loss Estimation Uncertainties (United States)

    Frolova, Nina; Bonnin, Jean; Larionov, Valery; Ugarov, Aleksander


    The paper addresses the reliability issues of strong earthquakes loss assessment following strong earthquakes with worldwide Systems' application in emergency mode. Timely and correct action just after an event can result in significant benefits in saving lives. In this case the information about possible damage and expected number of casualties is very critical for taking decision about search, rescue operations and offering humanitarian assistance. Such rough information may be provided by, first of all, global systems, in emergency mode. The experience of earthquakes disasters in different earthquake-prone countries shows that the officials who are in charge of emergency response at national and international levels are often lacking prompt and reliable information on the disaster scope. Uncertainties on the parameters used in the estimation process are numerous and large: knowledge about physical phenomena and uncertainties on the parameters used to describe them; global adequacy of modeling techniques to the actual physical phenomena; actual distribution of population at risk at the very time of the shaking (with respect to immediate threat: buildings or the like); knowledge about the source of shaking, etc. Needless to be a sharp specialist to understand, for example, that the way a given building responds to a given shaking obeys mechanical laws which are poorly known (if not out of the reach of engineers for a large portion of the building stock); if a carefully engineered modern building is approximately predictable, this is far not the case for older buildings which make up the bulk of inhabited buildings. The way population, inside the buildings at the time of shaking, is affected by the physical damage caused to the buildings is not precisely known, by far. The paper analyzes the influence of uncertainties in strong event parameters determination by Alert Seismological Surveys, of simulation models used at all stages from, estimating shaking intensity

  7. Earth's rotation variations and earthquakes 2010–2011

    Directory of Open Access Journals (Sweden)

    L. Ostřihanský


    Full Text Available In contrast to unsuccessful searching (lasting over 150 years for correlation of earthquakes with biweekly tides, the author found correlation of earthquakes with sidereal 13.66 days Earth's rotation variations expressed as length of a day (LOD measured daily by International Earth's Rotation Service. After short mention about earthquakes M 8.8 Denali Fault Alaska 3 November 2002 triggered on LOD maximum and M 9.1 Great Sumatra earthquake 26 December 2004 triggered on LOD minimum and the full Moon, the main object of this paper are earthquakes of period 2010–June 2011: M 7.0 Haiti (12 January 2010 on LOD minimum, M 8.8 Maule Chile 12 February 2010 on LOD maximum, map constructed on the Indian plate revealing 6 earthquakes from 7 on LOD minimum in Sumatra and Andaman Sea region, M 7.1 New Zealand Christchurch 9 September 2010 on LOD minimum and M 6.3 Christchurch 21 February 2011 on LOD maximum, and M 9.1 Japan near coast of Honshu 11 March 2011 on LOD minimum. It was found that LOD minimums coincide with full or new Moon only twice in a year in solstices. To prove that determined coincidences of earthquakes and LOD extremes stated above are not accidental events, histograms were constructed of earthquake occurrences and their position on LOD graph deeply in the past, in some cases from the time the IERS (International Earth's Rotation Service started to measure the Earth's rotation variations in 1962. Evaluations of histograms and the Schuster's test have proven that majority of earthquakes are triggered in both Earth's rotation deceleration and acceleration. Because during these coincidences evident movements of lithosphere occur, among others measured by GPS, it is concluded that Earth's rotation variations effectively contribute to the lithospheric plates movement. Retrospective overview of past earthquakes revealed that the Great Sumatra earthquake 26 December 2004 had its equivalent in the shape of LOD graph, full Moon position, and

  8. P wave crustal velocity structure in the greater Mount Rainier area from local earthquake tomography (United States)

    Moran, Seth C.; Lees, Jonathan M.; Malone, Stephen D.


    We present results from a local earthquake tomographic imaging experiment in the greater Mount Rainier area. We inverted P wave arrival times from local earthquakes recorded at permanent and temporary Pacific Northwest Seismograph Network seismographs between 1980 and 1996. We used a method similar to that described by Lees and Crosson [1989], modified to incorporate the parameter separation method for decoupling the hypocenter and velocity problems. In the upper 7 km of the resulting model there is good correlation between velocity anomalies and surface geology. Many focal mechanisms within the St. Helens seismic zone have nodal planes parallel to the epicentral trend as well as to a north-south trending low-velocity trough, leading us to speculate that the trough represents a zone of structural weakness in which a moderate (M 6.5-7.0) earthquake could occur. In contrast, the western Rainier seismic zone does not correlate in any simple way with anomaly patterns or focal mechanism fault planes, leading us to infer that it is less likely to experience a moderate earthquake. A ˜10 km-wide low-velocity anomaly occurs 5 to 18 km beneath the summit of Mount Rainier, which we interpret to be a signal of a region composed of hot, fractured rock with possible small amounts of melt or fluid. No systematic velocity pattern is observed in association with the southern Washington Cascades conductor. A midcrustal anomaly parallels the Olympic-Wallowa lineament as well as several other geophysical trends, indicating that it may play an important role in regional tectonics.

  9. Losses Associated with Secondary Effects in Earthquakes

    Directory of Open Access Journals (Sweden)

    James E. Daniell


    Full Text Available The number of earthquakes with high damage and high losses has been limited to around 100 events since 1900. Looking at historical losses from 1900 onward, we see that around 100 key earthquakes (or around 1% of damaging earthquakes have caused around 93% of fatalities globally. What is indeed interesting about this statistic is that within these events, secondary effects have played a major role, causing around 40% of economic losses and fatalities as compared to shaking effects. Disaggregation of secondary effect economic losses and fatalities demonstrating the relative influence of historical losses from direct earthquake shaking in comparison to tsunami, fire, landslides, liquefaction, fault rupture, and other type losses is important if we are to understand the key causes post-earthquake. The trends and major event impacts of secondary effects are explored in terms of their historic impact as well as looking to improved ways to disaggregate them through two case studies of the Tohoku 2011 event for earthquake, tsunami, liquefaction, fire, and the nuclear impact; as well as the Chilean 1960 earthquake and tsunami event.

  10. Uranium concentrations and 234U/238U activity ratios in fault-associated groundwater as possible earthquake precursors (United States)

    Finkel, R. C.

    In order to assess the utility of uranium isotopes as fluid phase earthquake precursors, uranium concentrations and 234U/238U activity ratios have been monitored on a monthly or bimonthly basis in water from 24 wells and springs associated with Southern California fault zones. Uranium concentrations vary from 0.002 ppb at Indian Canyon Springs on the San Jacinto fault to 8.3 ppb at Lake Hughes well on the San Andreas fault in the Palmdale area. 234U/238U activity ratios vary from 0.88 at Agua Caliente Springs on the Elsinore fault to 5.4 at Niland Slab well on the San Andreas fault in the Imperial Valley. There was one large earthquake in the study area during 1979, the 15 October 1979 M=6.6 Imperial Valley earthquake. Correlated with this event, uranium concentrations varied by a factor of more than 60 and activity ratios by a factor of 3 at the Niland Slab site, about 70 km from the epicenter. At the other sites monitored, uranium concentrations varied in time, but with no apparent pattern, while uranium activity ratios remained essentially constant throughout the monitoring period.

  11. The key role of eyewitnesses in rapid earthquake impact assessment (United States)

    Bossu, Rémy; Steed, Robert; Mazet-Roux, Gilles; Roussel, Frédéric; Etivant, Caroline


    Uncertainties in rapid earthquake impact models are intrinsically large even when excluding potential indirect losses (fires, landslides, tsunami…). The reason is that they are based on several factors which are themselves difficult to constrain, such as the geographical distribution of shaking intensity, building type inventory and vulnerability functions. The difficulties can be illustrated by two boundary cases. For moderate (around M6) earthquakes, the size of potential damage zone and the epicentral location uncertainty share comparable dimension of about 10-15km. When such an earthquake strikes close to an urban area, like in 1999, in Athens (M5.9), earthquake location uncertainties alone can lead to dramatically different impact scenario. Furthermore, for moderate magnitude, the overall impact is often controlled by individual accidents, like in 2002 in Molise, Italy (M5.7), in Bingol, Turkey (M6.4) in 2003 or in Christchurch, New Zealand (M6.3) where respectively 23 out of 30, 84 out of 176 and 115 out of 185 of the causalities perished in a single building failure. Contrastingly, for major earthquakes (M>7), the point source approximation is not valid anymore, and impact assessment requires knowing exactly where the seismic rupture took place, whether it was unilateral, bilateral etc.… and this information is not readily available directly after the earthquake's occurrence. In-situ observations of actual impact provided by eyewitnesses can dramatically reduce impact models uncertainties. We will present the overall strategy developed at the EMSC which comprises of crowdsourcing and flashsourcing techniques, the development of citizen operated seismic networks, and the use of social networks to engage with eyewitnesses within minutes of an earthquake occurrence. For instance, testimonies are collected through online questionnaires available in 32 languages and automatically processed in maps of effects. Geo-located pictures are collected and then

  12. Improved stress release model: Application to the study of earthquake prediction in Taiwan area

    Institute of Scientific and Technical Information of China (English)

    朱守彪; 石耀霖


    tress release model used to be applied to seismicity study of large historical earthquakes in a space of large scale. In this paper, we improve the stress release model, and discuss whether the stress release model is still applicable or not in the case of smaller spatio-temporal scale and weaker earthquakes. As an example of testing the model, we have analyzed the M(6 earthquakes in recent about 100 years. The result shows that the stress release model is still applicable. The earthquake conditional probability intensity in Taiwan area is calculated with the improved stress release model. We see that accuracy of earthquake occurrence time predicted by the improved stress release model is higher than that by Poisson model in the test of retrospect earthquake prediction.

  13. Time-Dependent Earthquake Forecasts on a Global Scale (United States)

    Rundle, J. B.; Holliday, J. R.; Turcotte, D. L.; Graves, W. R.


    We develop and implement a new type of global earthquake forecast. Our forecast is a perturbation on a smoothed seismicity (Relative Intensity) spatial forecast combined with a temporal time-averaged ("Poisson") forecast. A variety of statistical and fault-system models have been discussed for use in computing forecast probabilities. An example is the Working Group on California Earthquake Probabilities, which has been using fault-based models to compute conditional probabilities in California since 1988. An example of a forecast is the Epidemic-Type Aftershock Sequence (ETAS), which is based on the Gutenberg-Richter (GR) magnitude-frequency law, the Omori aftershock law, and Poisson statistics. The method discussed in this talk is based on the observation that GR statistics characterize seismicity for all space and time. Small magnitude event counts (quake counts) are used as "markers" for the approach of large events. More specifically, if the GR b-value = 1, then for every 1000 M>3 earthquakes, one expects 1 M>6 earthquake. So if ~1000 M>3 events have occurred in a spatial region since the last M>6 earthquake, another M>6 earthquake should be expected soon. In physics, event count models have been called natural time models, since counts of small events represent a physical or natural time scale characterizing the system dynamics. In a previous research, we used conditional Weibull statistics to convert event counts into a temporal probability for a given fixed region. In the present paper, we move belyond a fixed region, and develop a method to compute these Natural Time Weibull (NTW) forecasts on a global scale, using an internally consistent method, in regions of arbitrary shape and size. We develop and implement these methods on a modern web-service computing platform, which can be found at and We also discuss constraints on the User Interface (UI) that follow from practical considerations of site usability.

  14. Earthquake Science: a New Start

    Institute of Scientific and Technical Information of China (English)

    Chen Yun-tai


    @@ Understanding the mechanisms which cause earthquakes and thus earthquake prediction, is inher-ently difficult in comparison to other physical phenom-ena. This is due to the inaccessibility of the Earth's inte-rior, the infrequency of large earthquakes, and the com-plexities of the physical processes involved. Conse-quently, in its broadest sense, earthquake science--the science of studying earthquake phenomena, is a com-prehensive and inter-disciplinary field. The disciplines involved in earthquake science include: traditional seismology, earthquake geodesy, earthquake geology, rock mechanics, complex system theory, and informa-tion and communication technologies related to earth-quake studies.

  15. Long-Term Earthquake Forecasts in the San Francisco Bay Area: A Contrarian Perspective (United States)

    Lindh, A. G.


    In historic time the San Francisco Bay Area (SFBA) has been the site of four large earthquakes, including the M7.8 1906 San Francisco earthquake, and most recently, the M6.9 1989 Loma Prieta earthquake. Of the eight major fault segments considered here, two have not experienced large earthquakes in about 200 years, and the SF Peninsula segment of the 1906 rupture on the San Andreas appears from my calculations to be close to fully reloaded as well. I have used simple geophysical and statistical models (elastic rebound model and Weibull distribution) to estimate the probability of large earthquakes (M7 or larger) in the SFBA in the coming decades. I have used seismicity, geology, and geodesy to estimate segment boundaries, recurrence intervals, and the associated uncertainties. The results indicate that the SFBA has an approximately 80% chance of a large earthquake in the next 30 years, with four segments dominating the 30 yr probabilities; San Francisco Peninsula (32%), Southern Hayward (39%), Northern Hayward (28%) and Rodgers Cr (30%). Because of the proximity of these four segments to the urban portions of San Francisco and Oakland, the probability of these most vulnerable areas experiencing strong ground motion (an M7 within 25 km or less) one or more times within the next 30 years is about 70%. Because of the breadth and quality of our understanding of the earthquake machine in the SFBA, these probabilities depend in large part on the intrinsic variance in the earthquake recurrence process itself -- most conveniently expressed as the ratio of the standard deviation to the mean recurrence time, or intrinsic coefficient of variation (CVI). I have applied a new approach to estimating CVI, using the time since the last characteristic event (the "open-interval") on well characterized segments. Combined with an estimate of the mean recurrence time on each segment, an estimate of the likelihood of each open interval can be computed, and a simple maximum likelihood

  16. Inside a Crustal Earthquake - the Rock Evidence (United States)

    Sibson, R. H.


    Exhumed fault rock assemblages provide insights into fault zone structure, rupture processes and physical conditions of seismogenesis which can be melded with high-resolution geophysical information on modern earthquakes. The transition from dominantly cataclasite-series to mylonite-series fault rocks at greenschist and greater grades of metamorphism is the basis of fault zone models and rheological strength profiles defining the FR-VS (frictional-viscous) transition which governs the base of the microseismically defined seismogenic zone, within which larger ruptures are mostly contained. In areas of crust deforming under moderate-to-high heat flow (e.g. Japan, California) there is good correlation between geothermal gradient and the base of microseismic activity in the crust. However, compositional variations (e.g. quartz- vs. feldspar-dominant rheology) plus other factors such as water content locally perturb the base of the seismogenic zone, creating strength asperities which may affect the nucleation of large ruptures (e.g.1989 M6.9 Loma Prieta earthquake). The level of shear stress driving rupturing within the seismogenic zone remains problematic. While some estimates (e.g. those inferred from pseudotachylyte friction-melts) are broadly consistent with expectations for the frictional strength of optimally oriented faults with 'Byerlee friction' (τ ~ 80-240 MPa at 10 km depth, depending on faulting mode), others (e.g. faults with associated hydrothermal extension veins) appear to slip at much lower levels of shear stress (max. τ 90% of global seismic moment release) and areas of active compressional inversion (e.g. NE Honshu). However, while fault overpressuring is more easily generated and sustained in compressional regimes, it may be more widespread than once thought. The presence of incrementally deposited hydrothermal veins along fault slip surfaces (often associated with subsidiary extension vein arrays) is not uncommon in fault assemblages exhumed from


    Energy Technology Data Exchange (ETDEWEB)

    Kılıçoğlu, T.; Albayrak, B. [Ankara University, Faculty of Science, Department of Astronomy and Space Sciences, 06100, Tandoğan, Ankara (Turkey); Monier, R. [LESIA, UMR 8109, Observatoire de Paris Meudon, Place J. Janssen, Meudon (France); Richer, J. [Département de physique, Université de Montréal, 2900, Boulevard Edouard-Montpetit, Montréal QC, H3C 3J7 (Canada); Fossati, L., E-mail:, E-mail:, E-mail:, E-mail:, E-mail: [Argelander-Institut für Astronomie der Universität Bonn, Auf dem Hügel 71, D-53121, Bonn (Germany)


    We present here the first abundance analysis of 44 late B-, A-, and F-type members of the young open cluster M6 (NGC 6405, age about 75 Myr). Low- and medium-resolution spectra, covering the 4500–5840 Å wavelength range, were obtained using the FLAMES/GIRAFFE spectrograph attached to the ESO Very Large Telescopes. We determined the atmospheric parameters using calibrations of the Geneva photometry and by adjusting the H{sub β} profiles to synthetic ones. The abundances of up to 20 chemical elements, from helium to mercury, were derived for 19 late B, 16 A, and 9 F stars by iteratively adjusting synthetic spectra to the observations. We also derived a mean cluster metallicity of [Fe/H] = 0.07 ± 0.03 dex from the iron abundances of the F-type stars. We find that for most chemical elements, the normal late B- and A-type stars exhibit larger star-to-star abundance variations than the F-type stars probably because of the faster rotation of the B and A stars. The abundances of C, O, Mg, Si, and Sc appear to be anticorrelated with that of Fe, while the opposite holds for the abundances of Ca, Ti, Cr, Mn, Ni, Y, and Ba as expected if radiative diffusion is efficient in the envelopes of these stars. In the course of this analysis, we discovered five new peculiar stars: one mild Am, one Am, and one Fm star (HD 318091, CD-32 13109, GSC 07380-01211, CP1), one HgMn star (HD 318126, CP3), and one He-weak P-rich (HD 318101, CP4) star. We also discovered a new spectroscopic binary, most likely a SB2. We performed a detailed modeling of HD 318101, the new He-weak P-rich CP star, using the Montréal stellar evolution code XEVOL which self-consistently treats all particle transport processes. Although the overall abundance pattern of this star is properly reproduced, we find that detailed abundances (in particular the high P excess) resisted modeling attempts even when a range of turbulence profiles and mass-loss rates were considered. Solutions are proposed which are

  18. Brief communication "A pre seismic radio anomaly revealed in the area where the Abruzzo earthquake (M=6.3 occurred on 6 April 2009"

    Directory of Open Access Journals (Sweden)

    T. Ligonzo


    Full Text Available We report the information that in the days of the radio anomaly presented in the paper Biagi et al. (2009 an interruption of the broadcasting from the transmitter (RMC, France happened. It remains unclear if the action resulted in a complete power off of the system, or in a reduction in the radiated power, and if this has affected France only, or every direction. Should a complete power off have occurred, the proposed pre-seismic defocusing is inexistent. Our doubts on this action are reported.

  19. Using Smartphones to Detect Earthquakes (United States)

    Kong, Q.; Allen, R. M.


    We are using the accelerometers in smartphones to record earthquakes. In the future, these smartphones may work as a supplement network to the current traditional network for scientific research and real-time applications. Given the potential number of smartphones, and small separation of sensors, this new type of seismic dataset has significant potential provides that the signal can be separated from the noise. We developed an application for android phones to record the acceleration in real time. These records can be saved on the local phone or transmitted back to a server in real time. The accelerometers in the phones were evaluated by comparing performance with a high quality accelerometer while located on controlled shake tables for a variety of tests. The results show that the accelerometer in the smartphone can reproduce the characteristic of the shaking very well, even the phone left freely on the shake table. The nature of these datasets is also quite different from traditional networks due to the fact that smartphones are moving around with their owners. Therefore, we must distinguish earthquake signals from other daily use. In addition to the shake table tests that accumulated earthquake records, we also recorded different human activities such as running, walking, driving etc. An artificial neural network based approach was developed to distinguish these different records. It shows a 99.7% successful rate of distinguishing earthquakes from the other typical human activities in our database. We are now at the stage ready to develop the basic infrastructure for a smartphone seismic network.

  20. New geological perspectives on earthquake recurrence models

    Energy Technology Data Exchange (ETDEWEB)

    Schwartz, D.P. [Geological Survey, Menlo Park, CA (United States)


    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.

  1. Mapping of earthquakes vulnerability area in Papua (United States)

    Muhammad Fawzy Ismullah, M.; Massinai, Muh. Altin


    Geohazard is a geological occurrence which may lead to a huge loss for human. A mitigation of these natural disasters is one important thing to be done properly in order to reduce the risks. One of the natural disasters that frequently occurs in the Papua Province is the earthquake. This study applies the principle of Geospatial and its application for mapping the earthquake-prone area in the Papua region. It uses earthquake data, which is recorded for 36 years (1973-2009), fault location map, and ground acceleration map of the area. The earthquakes and fault map are rearranged into an earthquake density map, as well as an earthquake depth density map and fault density map. The overlaid data of these three maps onto ground acceleration map are then (compiled) to obtain an earthquake unit map. Some districts area, such as Sarmi, Nabire, and Dogiyai, are identified by a high vulnerability index. In the other hand, Waropen, Puncak, Merauke, Asmat, Mappi, and Bouven Digoel area shows lower index. Finally, the vulnerability index in other places is detected as moderate.

  2. 10th World Earthquake Engineering Conference (United States)

    Ranguelov, Boyko; Housner, George

    The 10th World Conference on Earthquake Engineering (10WCEE) took place from July 19 to 24 in Madrid, Spain. More than 1500 participants from 51 countries attended the conference. All aspects of earthquake engineering were covered and a worldwide update of modern research and practice, as well as future directions in the field, was provided through reports, papers, posters, two keynote lectures, ten state-ofthe-art reports, and eleven special theme sessions.

  3. Seismic energy trapped in a low velocity zone: the effects of the Yogyakarta earthquake at LUSI, Indonesia (United States)

    Lupi, Matteo; Saenger, Erik H.; Fuchs, Florian; Miller, Stephen A.


    On May 27, 2006, a M6.3 strike slip earthquake shook Yogyakarta, Java. Forty-seven hours later, hot mud reached the surface near Surabaya, 250 km far from the epicenter, creating several mud vents aligned along a NW-SE direction. The mud eruption reached a peak of 180.000 km3 of erupted material per day and it is still ongoing. The mud flooded several villages and caused a loss of approximately 4 billions to Indonesia. Geochemical analysis, geological data, and numerical simulations suggest that the earthquake may have initiated the liquefaction of the mud that then injected and reactivated a fault plane. However, the trigger mechanism of the eruption is still debated because a second hypothesis suggests that Lusi may have been triggered by a blowout following drilling problems in the nearby Banjar Panji-1 well. The earthquake-triggering hypothesis is supported by the evidence immediately after the main shock ongoing drilling operations experienced a loss of the drilling mud downhole. In addition, the eruption of the mud began only 47 hours after the Yogyakarta earthquake and the mud reached the surface at different locations aligned along the Watukosek fault, a strike-slip fault system that bridges LUSI with the nearby volcanic complex. Moreover, the Yogyakarta earthquake also affected the volcanic activity of Mt. Semeru, located even further than Lusi from the epicenter of the earthquake. However, the drilling-triggering hypothesis points out that the earthquake was too far from LUSI for inducing relevant stress changes at depth and highlights how upwelling fluids that reached the surface first emerged only 200 m far from the drilling rig that was operative at the time. Hence, was LUSI triggered by the earthquake or by drilling operations? We conducted a seismic wave propagation study on a geological model based on vp, vs, and density values for the different lithologies and seismic profiles of the crust beneath LUSI. Our analysis shows compelling evidence for

  4. The 1997 Kagoshima (Japan) Earthquake Doublet: A Quantitative Analysis of Stress Interaction (United States)

    Woessner, J.; Hauksson, E.; Wiemer, S.; Neukomm, S.


    Understanding how the nucleation of earthquakes is affected by sudden changes in the state of stress in their immediate vicinity may provide insight into the elusive relationship between static stress changes and earthquake occurrence. As working hypothesis, we assume that if aftershocks are in part caused by stress changes from their mainshock, changes in their decay rate may reflect changes in the state of stress induced by nearby large earthquakes. The 1997 Kagoshima (Japan) earthquake doublet provides a unique opportunity to analyze this hypothesis for two moderate M6 events that occurred on adjacent faults with the epicenters located in a distance of about 5 km from each other. We map the Omori law parameters on an equally spaced grid for the time period between the two mainshocks (the learning period of 47.8 days) using four Omori law type models with increasing complexity. The best fitting model is found using the corrected Akaike Criterion Information. We then forecast the number of aftershocks for the next 50 days and compare it to the actual observed number. Uncertainties in the rate forecasts are obtained by a bootstrap approach, allowing us to compute a detailed map of the significance of the relative rate changes. We find four regions with highly significant relative rate changes, three negative and one positive, which are a consequence of the activation and deactivation of aftershock activity due to the second mainshock, respectively. While our results confirm a relative rate drop in the Western part of the aftershock sequence that is in agreement with the stress triggering hypothesis (Stein, 2003), the other changes cannot be readily explained. Because of the importance of rate changes for the evaluation of the stress triggering hypothesis as well as for rate and state friction models, we consider our quantitative analysis technique introduced here important and a step forward in the process of understanding the behavior of aftershocks.

  5. Reduction of earthquake disasters

    Institute of Scientific and Technical Information of China (English)

    陈顒; 陈祺福; 黄静; 徐文立


    The article summarizes the researches on mitigating earthquake disasters of the past four years in China. The studyof earthquake disasters′ quantification shows that the losses increase remarkably when population concentrates inurban area and social wealth increase. The article also summarizes some new trends of studying earthquake disas-ters′ mitigation, which are from seismic hazard to seismic risk, from engineering disaster to social disaster andintroduces the community-centered approach.

  6. POST Earthquake Debris Management - AN Overview (United States)

    Sarkar, Raju

    Every year natural disasters, such as fires, floods, earthquakes, hurricanes, landslides, tsunami, and tornadoes, challenge various communities of the world. Earthquakes strike with varying degrees of severity and pose both short- and long-term challenges to public service providers. Earthquakes generate shock waves and displace the ground along fault lines. These seismic forces can bring down buildings and bridges in a localized area and damage buildings and other structures in a far wider area. Secondary damage from fires, explosions, and localized flooding from broken water pipes can increase the amount of debris. Earthquake debris includes building materials, personal property, and sediment from landslides. The management of this debris, as well as the waste generated during the reconstruction works, can place significant challenges on the national and local capacities. Debris removal is a major component of every post earthquake recovery operation. Much of the debris generated from earthquake is not hazardous. Soil, building material, and green waste, such as trees and shrubs, make up most of the volume of earthquake debris. These wastes not only create significant health problems and a very unpleasant living environment if not disposed of safely and appropriately, but also can subsequently impose economical burdens on the reconstruction phase. In practice, most of the debris may be either disposed of at landfill sites, reused as materials for construction or recycled into useful commodities Therefore, the debris clearance operation should focus on the geotechnical engineering approach as an important post earthquake issue to control the quality of the incoming flow of potential soil materials. In this paper, the importance of an emergency management perspective in this geotechnical approach that takes into account the different criteria related to the operation execution is proposed by highlighting the key issues concerning the handling of the construction

  7. Atmospheric Signals Associated with Major Earthquakes. A Multi-Sensor Approach. Chapter 9 (United States)

    Ouzounov, Dimitar; Pulinets, Sergey; Hattori, Katsumi; Kafatos, Menas; Taylor, Patrick


    We are studying the possibility of a connection between atmospheric observation recorded by several ground and satellites as earthquakes precursors. Our main goal is to search for the existence and cause of physical phenomenon related to prior earthquake activity and to gain a better understanding of the physics of earthquake and earthquake cycles. The recent catastrophic earthquake in Japan in March 2011 has provided a renewed interest in the important question of the existence of precursory signals preceding strong earthquakes. We will demonstrate our approach based on integration and analysis of several atmospheric and environmental parameters that were found associated with earthquakes. These observations include: thermal infrared radiation, radon! ion activities; air temperature and humidity and a concentration of electrons in the ionosphere. We describe a possible physical link between atmospheric observations with earthquake precursors using the latest Lithosphere-Atmosphere-Ionosphere Coupling model, one of several paradigms used to explain our observations. Initial results for the period of2003-2009 are presented from our systematic hind-cast validation studies. We present our findings of multi-sensor atmospheric precursory signals for two major earthquakes in Japan, M6.7 Niigata-ken Chuetsu-oki of July16, 2007 and the latest M9.0 great Tohoku earthquakes of March 11,2011

  8. Disturbances in equilibrium function after major earthquake (United States)

    Honma, Motoyasu; Endo, Nobutaka; Osada, Yoshihisa; Kim, Yoshiharu; Kuriyama, Kenichi


    Major earthquakes were followed by a large number of aftershocks and significant outbreaks of dizziness occurred over a large area. However it is unclear why major earthquake causes dizziness. We conducted an intergroup trial on equilibrium dysfunction and psychological states associated with equilibrium dysfunction in individuals exposed to repetitive aftershocks versus those who were rarely exposed. Greater equilibrium dysfunction was observed in the aftershock-exposed group under conditions without visual compensation. Equilibrium dysfunction in the aftershock-exposed group appears to have arisen from disturbance of the inner ear, as well as individual vulnerability to state anxiety enhanced by repetitive exposure to aftershocks. We indicate potential effects of autonomic stress on equilibrium function after major earthquake. Our findings may contribute to risk management of psychological and physical health after major earthquakes with aftershocks, and allow development of a new empirical approach to disaster care after such events.

  9. Hard X-ray and Microwave Simulation of 2015-06-22 M6.6 flare (United States)

    Kuroda, Natsuha; Wang, Haimin; Gary, Dale E.; Fleishman, Gregory D.; Nita, Gelu M.; Chen, Bin; Xu, Yan; Jing, Ju


    It is well known that the time profiles of the hard X-ray (HXR) emission and the microwave (MW) emission during the impulsive phase of the solar flare are well correlated, and this has led to the expectation that these emissions come from a common population of flare-accelerated electrons. However, the energy ranges of the electrons producing two emissions are believed to be different (below and above several hundred keV for HXR-producing and MW-producing electrons, respectively), and some studies have shown that the indices of their energy spectra may differ as well. To better understand the energy distributions of the electrons producing these emissions, we present realistic forward-fit simulations of the HXR and the MW emissions of 2015 June 22, M6.6 flare using the newly developed, IDL-based platform GX simulator. We use the 3D magnetic field model extrapolated from magnetogram data from the Helioseismic and Magnetic Imager (HMI) on board the Solar Dynamics Observatory (SDO), the images and the electron energy distribution parameters deduced from the photon spectrum from the Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI), and the spatially integrated MW spectrum and the cross-correlated amplitude data from the Expanded Owens Valley Solar Array (EOVSA) to guide the modeling. We have observed a possible above the-loop-top HXR source in 20-25 keV image, well separated from the source seen in 6-12 keV that is typically interpreted as a thermal loop-top source. Therefore, we simulate the HXR emissions by combining two flux tubes at different heights: the lower loop dominated by thermal electrons and the higher loop dominated by nonthermal electrons. The MW and HXR emissions produced from the forward-fit model are compared with observations to investigate possible differences in the energy spectra of the HXR-producing and the MW-producing electrons and what they can tell us about particle acceleration.

  10. Wave-equation Based Earthquake Location (United States)

    Tong, P.; Yang, D.; Yang, X.; Chen, J.; Harris, J.


    -equation earthquake location method. It is expected that this newly developed method can accurately obtain the origin time and hypocenter location of an earthquake (e.g., microseismic earthquake) in a complex structure. Moreover, the approach is suitable for estimating velocity structure as well as event location.

  11. An updated global earthquake catalogue for stable continental regions: Reassessing the correlation with ancient rifts (United States)

    Schulte, S.M.; Mooney, W.D.


    We present an updated global earthquake catalogue for stable continental regions (SCRs; i.e. intraplate earthquakes) that is available on the Internet. Our database contains information on location, magnitude, seismic moment and focal mechanisms for over 1300 M (moment magnitude) ??? 4.5 historic and instrumentally recorded crustal events. Using this updated earthquake database in combination with a recently published global catalogue of rifts, we assess the correlation of intraplate seismicity with ancient rifts on a global scale. Each tectonic event is put into one of five categories based on location: (i) interior rifts/taphrogens, (ii) rifted continental margins, (iii) non-rifted crust, (iv) possible interior rifts and (v) possible rifted margins. We find that approximately 27 per cent of all events are classified as interior rifts (i), 25 per cent are rifted continental margins (ii), 36 per cent are within non-rifted crust (iii) and 12 per cent (iv and v) remain uncertain. Thus, over half (52 per cent) of all events are associated with rifted crust, although within the continental interiors (i.e. away from continental margins), non-rifted crust has experienced more earthquakes than interior rifts. No major change in distribution is found if only large (M ??? 6.0) earthquakes are considered. The largest events (M ??? 7.0) however, have occurred predominantly within rifts (50 per cent) and continental margins (43 per cent). Intraplate seismicity is not distributed evenly. Instead several zones of concentrated seismicity seem to exist. This is especially true for interior rifts/taphrogens, where a total of only 12 regions are responsible for 74 per cent of all events and as much as 98 per cent of all seismic moment released in that category. Of the four rifts/taphrogens that have experienced the largest earthquakes, seismicity within the Kutch rift, India, and the East China rift system, may be controlled by diffuse plate boundary deformation more than by the

  12. Stem cells. m6A mRNA methylation facilitates resolution of naïve pluripotency toward differentiation. (United States)

    Geula, Shay; Moshitch-Moshkovitz, Sharon; Dominissini, Dan; Mansour, Abed AlFatah; Kol, Nitzan; Salmon-Divon, Mali; Hershkovitz, Vera; Peer, Eyal; Mor, Nofar; Manor, Yair S; Ben-Haim, Moshe Shay; Eyal, Eran; Yunger, Sharon; Pinto, Yishay; Jaitin, Diego Adhemar; Viukov, Sergey; Rais, Yoach; Krupalnik, Vladislav; Chomsky, Elad; Zerbib, Mirie; Maza, Itay; Rechavi, Yoav; Massarwa, Rada; Hanna, Suhair; Amit, Ido; Levanon, Erez Y; Amariglio, Ninette; Stern-Ginossar, Noam; Novershtern, Noa; Rechavi, Gideon; Hanna, Jacob H


    Naïve and primed pluripotent states retain distinct molecular properties, yet limited knowledge exists on how their state transitions are regulated. Here, we identify Mettl3, an N(6)-methyladenosine (m(6)A) transferase, as a regulator for terminating murine naïve pluripotency. Mettl3 knockout preimplantation epiblasts and naïve embryonic stem cells are depleted for m(6)A in mRNAs, yet are viable. However, they fail to adequately terminate their naïve state and, subsequently, undergo aberrant and restricted lineage priming at the postimplantation stage, which leads to early embryonic lethality. m(6)A predominantly and directly reduces mRNA stability, including that of key naïve pluripotency-promoting transcripts. This study highlights a critical role for an mRNA epigenetic modification in vivo and identifies regulatory modules that functionally influence naïve and primed pluripotency in an opposing manner.

  13. Sichuan Earthquake in China (United States)


    The Sichuan earthquake in China occurred on May 12, 2008, along faults within the mountains, but near and almost parallel the mountain front, northwest of the city of Chengdu. This major quake caused immediate and severe damage to many villages and cities in the area. Aftershocks pose a continuing danger, but another continuing hazard is the widespread occurrence of landslides that have formed new natural dams and consequently new lakes. These lakes are submerging roads and flooding previously developed lands. But an even greater concern is the possible rapid release of water as the lakes eventually overflow the new dams. The dams are generally composed of disintegrated rock debris that may easily erode, leading to greater release of water, which may then cause faster erosion and an even greater release of water. This possible 'positive feedback' between increasing erosion and increasing water release could result in catastrophic debris flows and/or flooding. The danger is well known to the Chinese earthquake response teams, which have been building spillways over some of the new natural dams. This ASTER image, acquired on June 1, 2008, shows two of the new large landslide dams and lakes upstream from the town of Chi-Kua-Kan at 32o12'N latitude and 104o50'E longitude. Vegetation is green, water is blue, and soil is grayish brown in this enhanced color view. New landslides appear bright off-white. The northern (top) lake is upstream from the southern lake. Close inspection shows a series of much smaller lakes in an elongated 'S' pattern along the original stream path. Note especially the large landslides that created the dams. Some other landslides in this area, such as the large one in the northeast corner of the image, occur only on the mountain slopes, so do not block streams, and do not form lakes.

  14. Sichuan Earthquake in China (United States)


    The Sichuan earthquake in China occurred on May 12, 2008, along faults within the mountains, but near and almost parallel the mountain front, northwest of the city of Chengdu. This major quake caused immediate and severe damage to many villages and cities in the area. Aftershocks pose a continuing danger, but another continuing hazard is the widespread occurrence of landslides that have formed new natural dams and consequently new lakes. These lakes are submerging roads and flooding previously developed lands. But an even greater concern is the possible rapid release of water as the lakes eventually overflow the new dams. The dams are generally composed of disintegrated rock debris that may easily erode, leading to greater release of water, which may then cause faster erosion and an even greater release of water. This possible 'positive feedback' between increasing erosion and increasing water release could result in catastrophic debris flows and/or flooding. The danger is well known to the Chinese earthquake response teams, which have been building spillways over some of the new natural dams. This ASTER image, acquired on June 1, 2008, shows two of the new large landslide dams and lakes upstream from the town of Chi-Kua-Kan at 32o12'N latitude and 104o50'E longitude. Vegetation is green, water is blue, and soil is grayish brown in this enhanced color view. New landslides appear bright off-white. The northern (top) lake is upstream from the southern lake. Close inspection shows a series of much smaller lakes in an elongated 'S' pattern along the original stream path. Note especially the large landslides that created the dams. Some other landslides in this area, such as the large one in the northeast corner of the image, occur only on the mountain slopes, so do not block streams, and do not form lakes.

  15. Earthquakes and Schools (United States)

    National Clearinghouse for Educational Facilities, 2008


    Earthquakes are low-probability, high-consequence events. Though they may occur only once in the life of a school, they can have devastating, irreversible consequences. Moderate earthquakes can cause serious damage to building contents and non-structural building systems, serious injury to students and staff, and disruption of building operations.…

  16. More Earthquake Misery

    Institute of Scientific and Technical Information of China (English)


    Less than four months after the devastation of the Wenchuan earthquake on May 12, another quake brings further death and destruction to southwest China on August 30, a 6.1-magnitude earthquake hit southwest China, the border of Sichuan Province and Yunnan Province. Panzhihua City, Huili County in Sichuan and Yuanmou County and Yongren County in Yunnan were worst hit.

  17. Bam Earthquake in Iran

    CERN Multimedia


    Following their request for help from members of international organisations, the permanent Mission of the Islamic Republic of Iran has given the following bank account number, where you can donate money to help the victims of the Bam earthquake. Re: Bam earthquake 235 - UBS 311264.35L Bubenberg Platz 3001 BERN

  18. A physically-based earthquake recurrence model for estimation of long-term earthquake probabilities (United States)

    Ellsworth, William L.; Matthews, Mark V.; Nadeau, Robert M.; Nishenko, Stuart P.; Reasenberg, Paul A.; Simpson, Robert W.


    A physically-motivated model for earthquake recurrence based on the Brownian relaxation oscillator is introduced. The renewal process defining this point process model can be described by the steady rise of a state variable from the ground state to failure threshold as modulated by Brownian motion. Failure times in this model follow the Brownian passage time (BPT) distribution, which is specified by the mean time to failure, μ, and the aperiodicity of the mean, α (equivalent to the familiar coefficient of variation). Analysis of 37 series of recurrent earthquakes, M -0.7 to 9.2, suggests a provisional generic value of α = 0.5. For this value of α, the hazard function (instantaneous failure rate of survivors) exceeds the mean rate for times > μ⁄2, and is ~ ~ 2 ⁄ μ for all times > μ. Application of this model to the next M 6 earthquake on the San Andreas fault at Parkfield, California suggests that the annual probability of the earthquake is between 1:10 and 1:13.

  19. Earthquake-induced Landslidingand Ground Damage In New Zealand (United States)

    Hancox, G. T.; Perrin, N. D.; Dellow, G. D.

    A study of landsliding caused by 22 historical earthquakes in New Zealand was completed at the end of 1997 (Hancox et al., 1997). The main aims of that study were to determine: (a) the nature and extent of landsliding and other ground damage (sand boils, subsidence and lateral spreading due to soil liquefaction) caused by historical earthquakes; (b) relationships between landsliding and earthquake magnitude, epicentre, faulting, geology and topography; (c) improved environmental criteria and ground classes for assigning MM intensities and seismic hazard assessments in N.Z. The data and results of the 1997 study have recently been summarised and expanded (Hancox et al., in press), and are described in this paper. Relationships developed from these studies indicate that the minimum magnitude for earthquake-induced landsliding (EIL) in N.Z. is about M 5, with significant landsliding occurring at M 6 or greater. The minimum MM intensity for landsliding is MM6, while the most common intensities for significant landsliding are MM7-8. The intensity threshold for soil liquefaction in New Zealand was found to be MM7 for sand boils, and MM8 for lateral spreading, although such effects may also occur at one intensity level lower in highly susceptible materials. The minimum magnitude for liquefaction phenomena in N.Z. is about M 6, compared to M 5 overseas where highly susceptible soils are probably more widespread. Revised environmental response criteria (landsliding, subsidence, liquefaction-induced sand boils and lateral spreading) have also been established for the New Zealand MM Intensity Scale, and provisional landslide susceptibility Ground Classes developed for assigning MM intensities in areas where there are few buildings. Other new data presented include a size/frequency distribution model for earthquake-induced landslides over the last 150 years and a preliminary EIL Opportunity model for N.Z. The application of EIL data and relationships for seismic hazard

  20. Demand surge following earthquakes (United States)

    Olsen, Anna H.


    Demand surge is understood to be a socio-economic phenomenon where repair costs for the same damage are higher after large- versus small-scale natural disasters. It has reportedly increased monetary losses by 20 to 50%. In previous work, a model for the increased costs of reconstruction labor and materials was developed for hurricanes in the Southeast United States. The model showed that labor cost increases, rather than the material component, drove the total repair cost increases, and this finding could be extended to earthquakes. A study of past large-scale disasters suggested that there may be additional explanations for demand surge. Two such explanations specific to earthquakes are the exclusion of insurance coverage for earthquake damage and possible concurrent causation of damage from an earthquake followed by fire or tsunami. Additional research into these aspects might provide a better explanation for increased monetary losses after large- vs. small-scale earthquakes.

  1. Modeling earthquake dynamics (United States)

    Charpentier, Arthur; Durand, Marilou


    In this paper, we investigate questions arising in Parsons and Geist (Bull Seismol Soc Am 102:1-11, 2012). Pseudo causal models connecting magnitudes and waiting times are considered, through generalized regression. We do use conditional model (magnitude given previous waiting time, and conversely) as an extension to joint distribution model described in Nikoloulopoulos and Karlis (Environmetrics 19: 251-269, 2008). On the one hand, we fit a Pareto distribution for earthquake magnitudes, where the tail index is a function of waiting time following previous earthquake; on the other hand, waiting times are modeled using a Gamma or a Weibull distribution, where parameters are functions of the magnitude of the previous earthquake. We use those two models, alternatively, to generate the dynamics of earthquake occurrence, and to estimate the probability of occurrence of several earthquakes within a year or a decade.

  2. PolyNano M.6.1.1 Process validation state-of-the-art

    DEFF Research Database (Denmark)

    Tosello, Guido; Hansen, Hans Nørgaard; Calaon, Matteo


    of experiment and uncertainty analysis. The focus is on polymeric materials and deposited metals; for completeness glass and bulk metallic glasses (BMG) are briefly described as well as they are also employed for surface micro/nano replication. As a mean of replication assessment, simulation for surface......An extensive state‐of‐the‐art research has been conducted in the field of replication of micro/nano geometries in order to assess the currently available capability both at research and application level. As it emerged from the investigation, polymers for devices and deposited metals for tool...

  3. Characteristics and Implication of the Earthquake Swarm Occurred in Fuzhou in September 1999

    Institute of Scientific and Technical Information of China (English)

    Yuan Dingqiang; Wang Jian


    On September 23, 1999, an earthquake swarm occurred in Fuzhou. Because the swarm occurred in the region where earthquakes occurred scarcely before and very close to the center of the city as well as shortly after the Jiji earthquake with Ms7.6 in Taiwan, September 21, 1999, has aroused interest broadly. In this paper, we analyzed the characteristics of spatial and temporal distribution of the earthquake swarm and validated magnitude-number constituent of the swarm is special. In present theory, the earthquake swarm means that a small scale macro original rupture has formed in the layer of the crust in Fuzhou region where moderately strong earthquake risk exists.

  4. Tsunami earthquake can occur elsewhere along the Japan Trench—Historical and geological evidence for the 1677 earthquake and tsunami (United States)

    Yanagisawa, H.; Goto, K.; Sugawara, D.; Kanamaru, K.; Iwamoto, N.; Takamori, Y.


    Since the 11 March 2011 Tohoku earthquake, the mechanisms of large earthquakes along the Japan Trench have been intensely investigated. However, characteristics of tsunami earthquakes, which trigger unusually large tsunami, remain unknown. The earthquake of 4 November 1677 was a tsunami earthquake striking the southern part of the Japan Trench. Its source mechanism remains unclear. This study elucidates the fault slip and moment magnitude of the 1677 earthquake and tsunami based on integrated analyses of historical documents, tsunami deposits, and numerical simulation. Geological survey results, the analytical results of thickness and grain size distributions and diatoms, revealed that tsunami deposits in a small pond at 11 m elevation were probably formed by the 1677 event. This finding and historical descriptions are useful as important constraint conditions to estimate unusually large fault slips and moment magnitude of the 1677 earthquake. Numerical simulation results reveal that 8.34-8.63 moment magnitude with the large 11-16 m slip area is necessary to satisfy the constraint conditions. This fault slip and magnitude are equivalent to those of the 1896 Sanriku earthquake: a well-known tsunami earthquake in the northern part of the Japan Trench. We therefore conclude that a tsunami earthquake of moment magnitude 8.3-8.6 with unusually large slip can occur elsewhere along the Japan Trench. This point should be considered for future tsunami risk assessment along the Japan Trench and along any trench having similar tectonic settings to those of the Japan Trench.

  5. Prediction of earthquake-triggered landslide event sizes (United States)

    Braun, Anika; Havenith, Hans-Balder; Schlögel, Romy


    Seismically induced landslides are a major environmental effect of earthquakes, which may significantly contribute to related losses. Moreover, in paleoseismology landslide event sizes are an important proxy for the estimation of the intensity and magnitude of past earthquakes and thus allowing us to improve seismic hazard assessment over longer terms. Not only earthquake intensity, but also factors such as the fault characteristics, topography, climatic conditions and the geological environment have a major impact on the intensity and spatial distribution of earthquake induced landslides. We present here a review of factors contributing to earthquake triggered slope failures based on an "event-by-event" classification approach. The objective of this analysis is to enable the short-term prediction of earthquake triggered landslide event sizes in terms of numbers and size of the affected area right after an earthquake event occurred. Five main factors, 'Intensity', 'Fault', 'Topographic energy', 'Climatic conditions' and 'Surface geology' were used to establish a relationship to the number and spatial extend of landslides triggered by an earthquake. The relative weight of these factors was extracted from published data for numerous past earthquakes; topographic inputs were checked in Google Earth and through geographic information systems. Based on well-documented recent earthquakes (e.g. Haiti 2010, Wenchuan 2008) and on older events for which reliable extensive information was available (e.g. Northridge 1994, Loma Prieta 1989, Guatemala 1976, Peru 1970) the combination and relative weight of the factors was calibrated. The calibrated factor combination was then applied to more than 20 earthquake events for which landslide distribution characteristics could be cross-checked. One of our main findings is that the 'Fault' factor, which is based on characteristics of the fault, the surface rupture and its location with respect to mountain areas, has the most important

  6. Impact of the Wenchuan Earthquake on Tourism in Sichuan, China

    Institute of Scientific and Technical Information of China (English)

    YANG Weiqiong; CHEN Guojie; WANG Daojie


    An intensive earthquake, the Wenchuan Earthquake of 8.0 on the Richter scale, struck western Sichuan, China on May 12, 2008. The earthquake has tremendously affected all industries in the quake-hit areas, with no exception :of the local tourism. The study of the effect of the earthquake on tourism enriches the theory of tourism, and more importantly,it well serves as the foundation for policy making. The objective of this study is to outline for readers the empirical findings on the various ways that the earthquake affected the operations and viability of tourism in the quake-hit areas. This paper is mainly divided into 3 parts. The first part is to discuss the importance of tourism in the quake-hit areas. The second is to analyze the influencing factors of tourism.The third is to assess the impact of the earthquake on tourism in Sichuan in different seasons.

  7. Bayesian kinematic earthquake source models (United States)

    Minson, S. E.; Simons, M.; Beck, J. L.; Genrich, J. F.; Galetzka, J. E.; Chowdhury, F.; Owen, S. E.; Webb, F.; Comte, D.; Glass, B.; Leiva, C.; Ortega, F. H.


    Most coseismic, postseismic, and interseismic slip models are based on highly regularized optimizations which yield one solution which satisfies the data given a particular set of regularizing constraints. This regularization hampers our ability to answer basic questions such as whether seismic and aseismic slip overlap or instead rupture separate portions of the fault zone. We present a Bayesian methodology for generating kinematic earthquake source models with a focus on large subduction zone earthquakes. Unlike classical optimization approaches, Bayesian techniques sample the ensemble of all acceptable models presented as an a posteriori probability density function (PDF), and thus we can explore the entire solution space to determine, for example, which model parameters are well determined and which are not, or what is the likelihood that two slip distributions overlap in space. Bayesian sampling also has the advantage that all a priori knowledge of the source process can be used to mold the a posteriori ensemble of models. Although very powerful, Bayesian methods have up to now been of limited use in geophysical modeling because they are only computationally feasible for problems with a small number of free parameters due to what is called the "curse of dimensionality." However, our methodology can successfully sample solution spaces of many hundreds of parameters, which is sufficient to produce finite fault kinematic earthquake models. Our algorithm is a modification of the tempered Markov chain Monte Carlo (tempered MCMC or TMCMC) method. In our algorithm, we sample a "tempered" a posteriori PDF using many MCMC simulations running in parallel and evolutionary computation in which models which fit the data poorly are preferentially eliminated in favor of models which better predict the data. We present results for both synthetic test problems as well as for the 2007 Mw 7.8 Tocopilla, Chile earthquake, the latter of which is constrained by InSAR, local high

  8. Multiplicative earthquake likelihood models incorporating strain rates (United States)

    Rhoades, D. A.; Christophersen, A.; Gerstenberger, M. C.


    SUMMARYWe examine the potential for strain-rate variables to improve long-term earthquake likelihood models. We derive a set of multiplicative hybrid earthquake likelihood models in which cell rates in a spatially uniform baseline model are scaled using combinations of covariates derived from earthquake catalogue data, fault data, and strain-rates for the New Zealand region. Three components of the strain rate estimated from GPS data over the period 1991-2011 are considered: the shear, rotational and dilatational strain rates. The hybrid model parameters are optimised for earthquakes of M 5 and greater over the period 1987-2006 and tested on earthquakes from the period 2012-2015, which is independent of the strain rate estimates. The shear strain rate is overall the most informative individual covariate, as indicated by Molchan error diagrams as well as multiplicative modelling. Most models including strain rates are significantly more informative than the best models excluding strain rates in both the fitting and testing period. A hybrid that combines the shear and dilatational strain rates with a smoothed seismicity covariate is the most informative model in the fitting period, and a simpler model without the dilatational strain rate is the most informative in the testing period. These results have implications for probabilistic seismic hazard analysis and can be used to improve the background model component of medium-term and short-term earthquake forecasting models.

  9. Differential energy radiation from two earthquakes in Japan with identical Mw: The Kyushu 1996 and Tottori 2000 earthquakes (United States)

    Choy, G.L.; Boatwright, J.


    We examine two closely located earthquakes in Japan that had identical moment magnitudes Mw but significantly different energy magnitudes Me. We use teleseismic data from the Global Seismograph Network and strong-motion data from the National Research Institute for Earth Science and Disaster Prevention's K-Net to analyze the 19 October 1996 Kyushu earthquake (Mw 6.7, Me 6.6) and the 6 October 2000 Tottori earthquake (Mw 6.7, Me 7.4). To obtain regional estimates of radiated energy ES we apply a spectral technique to regional (earthquake, we estimate an average regional attenuation Q(f) 230f0:65. For the strike-slip Tottori earthquake, the average regional attenuation is Q(f) 180f0:6. These attenuation functions are similar to those derived from studies of both California and Japan earthquakes. The regional estimate of ES for the Kyushu earthquake, 3:8 ?? 1014 J, is significantly smaller than that for the Tottori earthquake, ES 1:3 ?? 1015 J. These estimates correspond well with the teleseismic estimates of 3:9 ?? 1014 J and 1:8 ?? 1015 J, respectively. The apparent stress (Ta = ??Es/M0 with ?? equal to rigidity) for the Kyushu earthquake is 4 times smaller than the apparent stress for the Tottori earthquake. In terms of the fault maturity model, the significantly greater release of energy by the strike-slip Tottori earthquake can be related to strong deformation in an immature intraplate setting. The relatively lower energy release of the thrust-fault Kyushu earthquake can be related to rupture on mature faults at a subduction environment. The consistence between teleseismic and regional estimates of ES is particularly significant as teleseismic data for computing ES are routinely available for all large earthquakes whereas often there are no near-field data.

  10. Aerodynamics configuration conceptual design for ATLLAS-M6 analog transport aircraft%类 ATLLAS-M6运输机气动布局分析与设计

    Institute of Scientific and Technical Information of China (English)

    肖光明; 冯毅; 唐伟; 桂业伟


    根据德国宇航中心设计的ATLLAS-M6运输机的气动布局特点,利用基于类型函数和形状函数的CST方法对其进行了参数化建模,并初步计算分析了该外形的主要气动特性,包括配平特性、静/动稳定性以及控制面的控制效率等.研究结果表明,类ATLLAS-M6的气动性能基本满足高超声速运输机的设计要求,其气动布局方案是可以借鉴的.在此基础上,将进一步考虑运输机结构重量、热防护性能等对布局的约束,对其外形进行多学科优化设计.%The aerodynamic configuration study of ATLLAS-M6 transport aircraft proposed by the German Aerospace Center (DLR) is presented and discussed. The ATLLAS-M6 has a turbine-based combined cycle (TBCC) propulsion system, and it's aerodynamic configuration has the following characteristics: double delta-wing with low-aspect ratio, axial vertical tail, high-set horizontal tail and lifting body with high-fineness ratio. In this paper, a parameterized configuration is proposed via the "class function and shape function transformation technique" (CST) method. The aerodynamic characteristics are investigated, such as the trim characteristic, static/dynamic stability and control efficiency of control surfaces. The detail research indicated that the ATLLAS-M6 analog has a high hypersonic lift to drag ratio at the cruise state of low trimming angle of attack. The hypersonic stability derivatives predicted by the " dahlem-buck" method and the "prandtl-meyer" method shown that the transporter is static and dynamic stable in both lateral and directional directions and the proposed configuration is one of the feasible transporter choices. Yet, the aerodynamic configuration conceptual design of the hypersonic transport aircraft is a highly integrated project, several disciplines involved must be considered farther, such as structured materials and thermal protection system. Therefore, the "multidisciplinary design optimization" (MDO) method

  11. Phase Transformations and Earthquakes (United States)

    Green, H. W.


    Phase transformations have been cited as responsible for, or at least involved in, "deep" earthquakes for many decades (although the concept of "deep" has varied). In 1945, PW Bridgman laid out in detail the string of events/conditions that would have to be achieved for a solid/solid transformation to lead to a faulting instability, although he expressed pessimism that the full set of requirements would be simultaneously achieved in nature. Raleigh and Paterson (1965) demonstrated faulting during dehydration of serpentine under stress and suggested dehydration embrittlement as the cause of intermediate depth earthquakes. Griggs and Baker (1969) produced a thermal runaway model of a shear zone under constant stress, culminating in melting, and proposed such a runaway as the origin of deep earthquakes. The discovery of Plate Tectonics in the late 1960s established the conditions (subduction) under which Bridgman's requirements for earthquake runaway in a polymorphic transformation could be possible in nature and Green and Burnley (1989) found that instability during the transformation of metastable olivine to spinel. Recent seismic correlation of intermediate-depth-earthquake hypocenters with predicted conditions of dehydration of antigorite serpentine and discovery of metastable olivine in 4 subduction zones, suggests strongly that dehydration embrittlement and transformation-induced faulting are the underlying mechanisms of intermediate and deep earthquakes, respectively. The results of recent high-speed friction experiments and analysis of natural fault zones suggest that it is likely that similar processes occur commonly during many shallow earthquakes after initiation by frictional failure.

  12. Advanced Detection of Earthquake Wave for the Faults Concealed in Working Face of Mining Well%工作面隐伏断层矿井地震波超前探测

    Institute of Scientific and Technical Information of China (English)



    为防止生产过程中竞水事故的发生,保证掘进工作面的安全施工,根据矿井巷道地震波超前探测方法的特点和使用方法,对开滦唐山矿岳胥区掘进工作面中DF11断层及其伴生小断层、裂隙发育区的构造位置和富水性进行超前探测研究,并对水文地质情况进行分析探讨,为巷道设计.支护及矿井防治水提供依据,对岳胥区工程安全施工具有重要指导意义.%To prevent water inrush incidents in the production process and ensure the safety of heading face construction, according to the characteriRtics of and (he using methods of the advanced detection methods of earthquake wave of mine tunnel, the paper made advanced detection to the DF11 fault in the raining face of Kailuan Tangshan mine Yuexu zone, structural position and watery of associated small faults and fractured w>ne, analyzed the hydrogeological conditions, which provided basis for roadway design, support and control of water and had important guidance significance for the safety construction.

  13. Earthquake Disaster Management and Insurance

    Institute of Scientific and Technical Information of China (English)


    As one of the most powerful tools to reduce the earthquake loss, the Earthquake Disaster Management [EDM] and Insurance [EI] have been highlighted and have had a great progress in many countries in recent years. Earthquake disaster management includes a series of contents, such as earthquake hazard and risk analysis, vulnerability analysis of building and infrastructure, earthquake aware training, and building the emergency response system. EI, which has been included in EDM after this practice has been...

  14. 抗震救灾官兵生活质量和心理健康状况及影响因素研究%Study on the quality of life and mental health as well as their influence factors in armed officers and soldiers from earthquake relief work

    Institute of Scientific and Technical Information of China (English)

    夜晓亮; 张步振


    目的 了解抗震救灾官兵生活质量和心理健康状况及影响因素.方法 采用随机整群抽样法,应用WHOQOL-BREF和SCL-90量表,对驻昆明某部280名抗震救灾官兵和330名非抗震救灾官兵进行问卷调查.结果 (1)抗震救灾官兵生活质量的生理、心理、社会及环境各领域百分制得分分别为(58.65±15.02)分、(56.88±14.66)分、(63.01±17.92)分、(50.73±15.16)分.除社会领域外,其余三个领域与非抗震救灾官兵之间的差异有统计学意义(P<0.01或P< 0.05).(2)在SCL-90评分中,除躯体化因子分外,抗震救灾官兵在其余各因子分均高于非抗震救灾官兵,且在强迫、抑郁、焦虑、恐怖、偏执和总均分两组之间的差异有统计学意义(P<0.01).(3)民族、籍贯、学历、职别、婚姻状况和是否为独生子女对抗震救灾官兵生活质量和SCL-90评分有不同程度的影响和相关性(P<0.01或P< 0.05).结论 抗震救灾官兵生活质量和心理健康水平均比非抗震救灾官兵差,其影响因素主要有民族、籍贯、学历、职别、婚姻状况和是否为独生子女等.%Objective To understand the quality of life and mental health status and influence factors on armed officers and soldiers from earthquake relief work. Methods sing cluster sampling and WHOQOL-BREF as well as the SCL-90 scale, a questionnaire survey was conducted in 280 officers and soldiers from earthquake relief work and 330 officers and soldiers not from earthquake relief work in Kunming. Results The scores of physiological, psychological, social and environmental domains of QOL among officers and soldiers from earthquake relief work were (58.65±15.02), (56.88±14.66), (63.01±l7.92), and (50.73±15.16), respectively. Statistically significant difference was found in the physiological, psychological, and environmental domains between officers and soldiers from earthquake relief work and those not from earthquake relief work (P<0.01 or P<0

  15. Earthquakes and emergence (United States)

    Earthquakes and emerging infections may not have a direct cause and effect relationship like tax evasion and jail, but new evidence suggests that there may be a link between the two human health hazards. Various media accounts have cited a massive 1993 earthquake in Maharashtra as a potential catalyst of the recent outbreak of plague in India that has claimed more than 50 lives and alarmed the world. The hypothesis is that the earthquake may have uprooted underground rat populations that carry the fleas infected with the bacterium that causes bubonic plague and can lead to the pneumonic form of the disease that is spread through the air.

  16. Earthquake engineering in Peru (United States)

    Vargas, N.J


    During the last decade, earthquake engineering research in Peru has been carried out at the Catholic University of Peru and at the Universidad Nacional de Ingeniera (UNI). The Geophysical Institute (IGP) under the auspices of the Organization of American States (OAS) has initiated in Peru other efforts in regional seismic hazard assessment programs with direct impact to the earthquake engineering program. Further details on these programs have been reported by L. Ocola in the Earthquake Information Bulletin, January-February 1982, vol. 14, no. 1, pp. 33-38. 

  17. Coseismic and postseismic deformation due to the 2007 M5.5 Ghazaband fault earthquake, Balochistan, Pakistan (United States)

    Fattahi, H.; Amelung, F.; Chaussard, E.; Wdowinski, S.


    Time series analysis of interferometric synthetic aperture radar data reveals coseismic and postseismic surface displacements associated with the 2007 M5.5 earthquake along the southern Ghazaband fault, a major but little studied fault in Pakistan. Modeling indicates that the coseismic surface deformation was caused by ~9 cm of strike-slip displacement along a shallow subvertical fault. The earthquake was followed by at least 1 year of afterslip, releasing ~70% of the moment of the main event, equivalent to a M5.4 earthquake. This high aseismic relative to the seismic moment release is consistent with previous observations for moderate earthquakes (M < 6) and suggests that smaller earthquakes are associated with a higher aseismic relative to seismic moment release than larger earthquakes.

  18. A statistical feature of anomalous seismic activities prior to large shallow earthquakes in Japan revealed by the Pattern Informatics method

    Directory of Open Access Journals (Sweden)

    M. Kawamura


    Full Text Available For revealing the preparatory processes of large inland earthquakes, we systematically applied the Pattern Informatics method (PI method to the earthquake data of Japan. We focused on 12 large earthquakes with magnitudes larger than M = 6.4 (an official magnitude of the Japan Meteorological Agency that occurred at depths shallower than 30 km between 2000 and 2010. We examined the relation between the spatiotemporal locations of such large shallow earthquakes and those of PI hotspots, which correspond to the grid cells of anomalous seismic activities in a designated time span. Based on a statistical test using Molchan's error diagram, we inquired into the existence of precursory anomalous seismic activities of the large earthquakes and, if any, their characteristic time span. The test indicated that the Japanese M ≧ 6.4 inland earthquakes tend to be preceded by anomalous seismic activities of 8-to-10-yr time scales.

  19. Investigating the mechanics of earthquakes using macroscopic seismic parameters (United States)

    Venkataraman, Anupama


    To understand the physics of earthquake rupture mechanics, we have to relate seismologically observable parameters to the dynamics of faulting. One of the key seismological parameters that will help us achieve this objective is the energy radiated by seismic waves. In this work, we develop a new method of estimating radiated energy from regional data using an empirical Green's function method; we also modify existing methods of estimating radiated energy from teleseismic data by improving the corrections applied to the observed seismic data for attenuation and directivity effects. We compute teleseismic estimates of radiated energy for 23 large subduction zone earthquakes recorded between 1992 and 2001; most of these earthquakes have a magnitude Mw > 7.5, but we also include some smaller (Mw ˜ 6.7) well-studied subduction zone earthquakes and 6 crustal earthquakes. We compile the static stress drop estimates for these 29 earthquakes from published literature. We then determine radiation efficiency of these earthquakes using a stress relaxation model that relates measurable and macroscopic seismological parameters to the physical processes on the fault zone via fracture energy. We also determine the rupture velocity of these earthquakes from published literature. A comparison of radiation efficiencies and rupture velocities of these earthquakes with the expected theoretical values for different modes crack propagation validates the use of the stress relaxation model to understand earthquake rupture mechanics. From our calculations, we observe that most earthquakes have radiation efficiencies between 0.25 and 1 and are hence efficient in generating seismic waves, but tsunami earthquakes and two deep earthquakes, the 1994 deep earthquake that occurred in Bolivia and the 1999 Russia-China border earthquake, have very small radiation efficiencies (<0.25) and hence dissipate a large amount of energy on the fault plane. We suggest that the difference in the radiation

  20. Earthquake probabilities in the San Francisco Bay Region: 2000 to 2030 - a summary of findings (United States)



    The San Francisco Bay region sits astride a dangerous “earthquake machine,” the tectonic boundary between the Pacific and North American Plates. The region has experienced major and destructive earthquakes in 1838, 1868, 1906, and 1989, and future large earthquakes are a certainty. The ability to prepare for large earthquakes is critical to saving lives and reducing damage to property and infrastructure. An increased understanding of the timing, size, location, and effects of these likely earthquakes is a necessary component in any effective program of preparedness. This study reports on the probabilities of occurrence of major earthquakes in the San Francisco Bay region (SFBR) for the three decades 2000 to 2030. The SFBR extends from Healdsberg on the northwest to Salinas on the southeast and encloses the entire metropolitan area, including its most rapidly expanding urban and suburban areas. In this study a “major” earthquake is defined as one with M≥6.7 (where M is moment magnitude). As experience from the Northridge, California (M6.7, 1994) and Kobe, Japan (M6.9, 1995) earthquakes has shown us, earthquakes of this size can have a disastrous impact on the social and economic fabric of densely urbanized areas. To reevaluate the probability of large earthquakes striking the SFBR, the U.S. Geological Survey solicited data, interpretations, and analyses from dozens of scientists representing a wide crosssection of the Earth-science community (Appendix A). The primary approach of this new Working Group (WG99) was to develop a comprehensive, regional model for the long-term occurrence of earthquakes, founded on geologic and geophysical observations and constrained by plate tectonics. The model considers a broad range of observations and their possible interpretations. Using this model, we estimate the rates of occurrence of earthquakes and 30-year earthquake probabilities. Our study considers a range of magnitudes for earthquakes on the major faults in the

  1. The Characteristics of Earthquake Disasters and Countermeasures for Their Mitigation in Metropolitans

    Institute of Scientific and Technical Information of China (English)

    Gao Mengtan


    Metropolitans are a result of fast economic development in China. Many metropolitans have emerged in the eastern part of China. Earthquake disasters in metropolitans are more complicated and serious than those in a smaller city, and the impact of earthquake disaster on the economy and society is large. The characteristics of earthquake disasters and countermeasures to protect against and mitigate disaster in the metropolitan, as well as some key research fields in the earthquake disaster protection and mitigation, are discussed.

  2. Clustered and transient earthquake sequences in mid-continents (United States)

    Liu, M.; Stein, S. A.; Wang, H.; Luo, G.


    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.

  3. Post-Earthquake Reconstruction — in Context of Housing (United States)

    Sarkar, Raju

    Comprehensive rescue and relief operations are always launched with no loss of time with active participation of the Army, Governmental agencies, Donor agencies, NGOs, and other Voluntary organizations after each Natural Disaster. There are several natural disasters occurring throughout the world round the year and one of them is Earthquake. More than any other natural catastrophe, an earthquake represents the undoing of our most basic pre-conceptions of the earth as the source of stability or the first distressing factor due to earthquake is the collapse of our dwelling units. Earthquake has affected buildings since people began constructing them. So after each earthquake a reconstruction of housing program is very much essential since housing is referred to as shelter satisfying one of the so-called basic needs next to food and clothing. It is a well-known fact that resettlement (after an earthquake) is often accompanied by the creation of ghettos and ensuing problems in the provision of infrastructure and employment. In fact a housing project after Bhuj earthquake in Gujarat, India, illustrates all the negative aspects of resettlement in the context of reconstruction. The main theme of this paper is to consider few issues associated with post-earthquake reconstruction in context of housing, all of which are significant to communities that have had to rebuild after catastrophe or that will face such a need in the future. Few of them are as follows: (1) Why rebuilding opportunities are time consuming? (2) What are the causes of failure in post-earthquake resettlement? (3) How can holistic planning after an earthquake be planned? (4) What are the criteria to be checked for sustainable building materials? (5) What are the criteria for success in post-earthquake resettlement? (6) How mitigation in post-earthquake housing can be made using appropriate repair, restoration, and strengthening concepts?

  4. Characterization of the radiation environment at the UNLV accelerator facility during operation of the Varian M6 linac (United States)

    Hodges, M.; Barzilov, A.; Chen, Y.; Lowe, D.


    The bremsstrahlung photon flux from the UNLV particle accelerator (Varian M6 model) was determined using MCNP5 code for 3 MeV and 6 MeV incident electrons. Human biological equivalent dose rates due to accelerator operation were evaluated using the photon flux with the flux-to-dose conversion factors. Dose rates were computed for the accelerator facility for M6 linac use under different operating conditions. The results showed that the use of collimators and linac internal shielding significantly reduced the dose rates throughout the facility. It was shown that the walls of the facility, in addition to the earthen berm enveloping the building, provide equivalent shielding to reduce dose rates outside to below the 2 mrem/h limit.

  5. Earthquake Counting Method for Spatially Localized Probabilities: Challenges in Real-Time Information Delivery

    CERN Document Server

    Holliday, James R; Rundle, John B; Turcotte, Donald L


    We develop and implement a new type of global earthquake forecast. Our forecast is a perturbation on a smoothed seismicity (Relative Intensity) spatial forecast combined with a temporal time-averaged (Poisson) forecast. A variety of statistical and fault-system models have been discussed for use in computing forecast probabilities. Our paper takes a new approach. The idea is based on the observation that GR statistics characterize seismicity for all space and time. Small magnitude event counts (quake counts) are used as markers for the approach of large events. More specifically, if the GR b-value = 1, then for every 1000 M>3 earthquakes, one expects 1 M>6 earthquake. So if ~1000 M>3 events have occurred in a spatial region since the last M>6 earthquake, another M>6 earthquake should be expected soon. In physics, event count models have been called natural time models, since counts of small events represent a physical or natural time scale characterizing the system dynamics. In a previous paper, we used condi...

  6. Tweet Earthquake Dispatch (TED) (United States)

    U.S. Geological Survey, Department of the Interior — The USGS is offering earthquake alerts via two twitter accounts: @USGSted and @USGSBigQuakes. On average, @USGSted and @USGSBigQuakes will produce about one tweet...

  7. 1988 Spitak Earthquake Database (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The 1988 Spitak Earthquake database is an extensive collection of geophysical and geological data, maps, charts, images and descriptive text pertaining to the...

  8. Earthquake Damage to Schools (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This set of slides graphically illustrates the potential danger that major earthquakes pose to school structures and to the children and adults who happen to be...

  9. Bayesian historical earthquake relocation: an example from the 1909 Taipei earthquake (United States)

    Minson, Sarah E.; Lee, William H.K.


    Locating earthquakes from the beginning of the modern instrumental period is complicated by the fact that there are few good-quality seismograms and what traveltimes do exist may be corrupted by both large phase-pick errors and clock errors. Here, we outline a Bayesian approach to simultaneous inference of not only the hypocentre location but also the clock errors at each station and the origin time of the earthquake. This methodology improves the solution for the source location and also provides an uncertainty analysis on all of the parameters included in the inversion. As an example, we applied this Bayesian approach to the well-studied 1909 Mw 7 Taipei earthquake. While our epicentre location and origin time for the 1909 Taipei earthquake are consistent with earlier studies, our focal depth is significantly shallower suggesting a higher seismic hazard to the populous Taipei metropolitan area than previously supposed.

  10. Thermal Runaway during Intermediate-Depth Earthquake Rupture (United States)

    Prieto, German; Florez, Manuel; Barrett, Sarah; Beroza, Gregory; Pedraza, Patricia; Blanco, Jose; Poveda, Esteban


    Intermediate-depth earthquakes occur at depths of 50 to 300 km in subducting lithosphere. Despite their ubiquity in earthquake catalogs, their physical mechanism remains unclear because ambient temperatures and pressures are expected to lead to ductile, rather than brittle deformation. There are two leading explanations for the physical mechanism that enables these earthquakes. In the first, high pore pressure from metamorphic dehydration reactions in the subducting slab reduces the effective normal stress sufficiently to enable frictional failure. In the second, slow deformation generates heat, which leads to weakening, further deformation, and a self-localizing thermal shear runaway. We use the nest of intermediate-depth earthquakes under Bucaramanga, Colombia as recorded by the digital RSNC (Red Sísmica Nacional de Colombia) regional seismic network to explore these two possibilities. We observe a combination of high stress drop and low radiation efficiency for Mw 4-5 earthquakes in the Bucaramanga Nest that points to the importance of thermal effects. If we assume a cm-scale fault-zone width, this combination implies a temperature increase of 600-1,000ºC during earthquake failure, which suggests that substantial shear heating, and possibly partial melting, occurs during intermediate-depth earthquake failure. Our observations support thermal shear runaway as the mechanism for intermediate-depth earthquakes. This mechanism could help explain differences in their behavior, such as the paucity of aftershocks, compared to shallow earthquakes. Although we have inferred these mechanisms for intermediate depth earthquakes, it's likely that they would apply for rapid deformation on the deep extensions of fault zones as well - particularly during large earthquakes, such as the 2012 Mw 8.6 strike-slip event off Sumatra, which is inferred to have ruptured well into the oceanic mantle.

  11. Charles Darwin's earthquake reports (United States)

    Galiev, Shamil


    As it is the 200th anniversary of Darwin's birth, 2009 has also been marked as 170 years since the publication of his book Journal of Researches. During the voyage Darwin landed at Valdivia and Concepcion, Chile, just before, during, and after a great earthquake, which demolished hundreds of buildings, killing and injuring many people. Land was waved, lifted, and cracked, volcanoes awoke and giant ocean waves attacked the coast. Darwin was the first geologist to observe and describe the effects of the great earthquake during and immediately after. These effects sometimes repeated during severe earthquakes; but great earthquakes, like Chile 1835, and giant earthquakes, like Chile 1960, are rare and remain completely unpredictable. This is one of the few areas of science, where experts remain largely in the dark. Darwin suggested that the effects were a result of ‘ …the rending of strata, at a point not very deep below the surface of the earth…' and ‘…when the crust yields to the tension, caused by its gradual elevation, there is a jar at the moment of rupture, and a greater movement...'. Darwin formulated big ideas about the earth evolution and its dynamics. These ideas set the tone for the tectonic plate theory to come. However, the plate tectonics does not completely explain why earthquakes occur within plates. Darwin emphasised that there are different kinds of earthquakes ‘...I confine the foregoing observations to the earthquakes on the coast of South America, or to similar ones, which seem generally to have been accompanied by elevation of the land. But, as we know that subsidence has gone on in other quarters of the world, fissures must there have been formed, and therefore earthquakes...' (we cite the Darwin's sentences following researchspace. auckland. ac. nz/handle/2292/4474). These thoughts agree with results of the last publications (see Nature 461, 870-872; 636-639 and 462, 42-43; 87-89). About 200 years ago Darwin gave oneself airs by the

  12. Recent damaging earthquakes in Japan, 2003-2008 (United States)

    Kayen, Robert E


    During the last six years, from 2003-2008, Japan has been struck by three significant and damaging earthquakes: The most recent M6.6 Niigata Chuetsu Oki earthquake of July 16, 2007 off the coast of Kashiwazaki City, Japan; The M6.6 Niigata Chuetsu earthquake of October 23, 2004, located in Niigata Prefecture in the central Uonuma Hills; and the M8.0 Tokachi Oki Earthquake of September 26, 2003 effecting southeastern Hokkaido Prefecture. These earthquakes stand out among many in a very active period of seismicity in Japan. Within the upper 100 km of the crust during this period, Japan experienced 472 earthquakes of magnitude 6, or greater. Both Niigata events affected the south-central region of Tohoku Japan, and the Tokachi-Oki earthquake affected a broad region of the continental shelf and slope southeast of the Island of Hokkaido. This report is synthesized from the work of scores of Japanese and US researchers who led and participated in post-earthquake reconnaissance of these earthquakes: their noteworthy and valuable contributions are listed in an extended acknowledgements section at the end of the paper. During the Niigata Chuetsu Oki event of 2007, damage to the Kashiwazaki-Kariwa nuclear power plant, structures, infrastructure, and ground were primarily the product of two factors: (1) high intensity motions from this moderate-sized shallow event, and (2) soft, poor performing, or liquefiable soils in the coastal region of southwestern Niigata Prefecture. Structural and geotechnical damage along the slopes of dunes was ubiquitous in the Kashiwazaki-Kariwa region. The 2004 Niigata Chuetsu Earthquake was the most significant to affect Japan since the 1995 Kobe earthquake. Forty people were killed, almost 3,000 were injured, and many hundreds of landslides destroyed entire upland villages. Landslides were of all types; some dammed streams, temporarily creating lakes threatening to overtop their new embankments and cause flash floods and mudslides. The numerous

  13. The role of INGVterremoti blog in information management during the earthquake sequence in central Italy

    Directory of Open Access Journals (Sweden)

    Maurizio Pignone


    Full Text Available In this paper, we describe the role the INGVterremoti blog in information management during the first part of the earthquake sequence in central Italy (August 24 to September 30. In the last four years, we have been working on the INGVterremoti blog in order to provide quick updates on the ongoing seismic activity in Italy and in-depth scientific information. These include articles on specific historical earthquakes, seismic hazard, geological interpretations, source models from different type of data, effects at the surface, and so on. We have delivered information in quasi-real-time also about all the recent magnitude M≥4.0 earthquakes in Italy, the strongest events in the Mediterranean and in the world. During the 2016 central Italy, the INGVterremoti blog has continuously released information about seismic sequences with three types of posts: i updates on the ongoing seismic activity; ii reports on the activities carried out by the INGV teams in the field and any other working groups; iii in-depth scientific articles describing some specific analysis and results. All the blog posts have been shared automatically and in real time on the other social media of the INGVterremoti platform, also to counter the bad information and to fight rumors. These include Facebook, Twitter and INGVterremoti App on IOS and Android. As well, both the main INGV home page ( and the INGV earthquake portal ( have published the contents of the blog on dedicated pages that were fed automatically. The work done day by day on the INGVterremoti blog has been coordinated with the INGV Press Office that has written several press releases based on the contents of the blog. Since August 24, 53 articles were published on the blog they have had more than 1.9 million views and 1 million visitors. The peak in the number of views, which was more than 800,000 in a single day, was registered on August 24, 2016, following the M 6

  14. Variability of earthquake stress drop in a subduction setting, the Hikurangi Margin, New Zealand (United States)

    Abercrombie, Rachel E.; Bannister, Stephen; Ristau, John; Doser, Diane


    We calculate stress drops for 176 earthquakes (M2.6-M6.6) from four sequences of earthquakes in New Zealand. Two sequences are within the subducting Pacific plate (2014 Eketahuna and 2005 Upper Hutt), one in the over-riding plate (2013 Cook Strait) and one involved reverse faulting at the subduction interface (2015 Pongaroa). We focus on obtaining precise and accurate measurements of corner frequency and stress drop for the best-recorded earthquakes. We use an empirical Green's function (EGF) approach, and require the EGF earthquakes to be highly correlated (cross-correlation ≥ 0.8) to their respective main shocks. In order to improve the quality, we also stack the spectral ratios and source time functions obtained from the best EGF. We perform a grid search for each individual ratio, and each stacked ratio to obtain quantitative uncertainty measurements, and restrict our analysis to the well-constrained corner frequency measurements. We are able to analyse both P and S waves independently and the high correlation between these measurements strengthens the reliability of our results. We find that there is significant real variability in corner frequency, and hence stress drop, within each sequence; the range of almost 2 orders of magnitude is larger than the uncertainties. The four sequences have overlapping stress drop ranges, and the variability within a sequence is larger than any between different sequences. There is no clear systematic difference in the populations analysed here with tectonic setting. We see no dependence of the stress drop values on depth, time, or magnitude after taking the frequency bandwidth limitations into consideration. Small-scale heterogeneity must therefore exert a more primary influence on earthquake stress drop than these larger scale factors. We confirm that when fitting individual spectral ratios, a corner frequency within a factor of three of the maximum signal frequency is likely to be underestimated. Stacked ratios are

  15. Lessons Learned from Eight Years' Experience of Actual Operation, and Future Prospects of JMA Earthquake Early Warning System (United States)

    Hoshiba, M.; Nishimae, Y.


    Since 2007, experiences of actual operation of EEW have been gained by the Japan Meteorological Agency (JMA). During this period, we have learned lessons from many M6- and M7-class earthquakes, and the Mw9.0 Tohoku earthquake. During the Mw9.0 Tohoku earthquake, JMA system functioned well: it issued a warning message more than 15 s before strong ground shaking in the Tohoku district (relatively near distance from the epicenter). However, it was not perfect: in addition to the problem of large extent of fault rupture, some false warning messages were issued due to the confusion of the system because of simultaneous multiple aftershocks which occurred at the wide rupture area. To address the problems, JMA will introduce two new methods into the operational system this year to start their tests, aiming at practical operation within a couple of years. One is Integrated Particle Filter (IPF) method, which is an integrated algorithm of multiple hypocenter determination techniques with Bayesian estimation, in which amplitude information is also used for hypocenter determination. The other is Propagation of Local Undamped Motion (PLUM) method, in which warning message is issued when strong ground shaking is detected at nearby stations around the target site (e.g., within 30 km). Here, hypocenter and magnitude are not required in PLUM. Aiming at application for several years later, we are investigating a new approach, in which current wavefield is estimated in real time, and then future wavefield is predicted time evolutionally from the current situation using physics of wave propagation. Here, hypocenter and magnitude are not necessarily required, but real-time observation of ground shaking is necessary. JMA also plans to predict long period ground motion (up to 8 s) with the EEW system for earthquake damage mitigation in high-rise buildings. Its test will start using the operational system in the near future.

  16. Development of an Earthquake Impact Scale (United States)

    Wald, D. J.; Marano, K. D.; Jaiswal, K. S.


    With the advent of the USGS Prompt Assessment of Global Earthquakes for Response (PAGER) system, domestic (U.S.) and international earthquake responders are reconsidering their automatic alert and activation levels as well as their response procedures. To help facilitate rapid and proportionate earthquake response, we propose and describe an Earthquake Impact Scale (EIS) founded on two alerting criteria. One, based on the estimated cost of damage, is most suitable for domestic events; the other, based on estimated ranges of fatalities, is more appropriate for most global events. Simple thresholds, derived from the systematic analysis of past earthquake impact and response levels, turn out to be quite effective in communicating predicted impact and response level of an event, characterized by alerts of green (little or no impact), yellow (regional impact and response), orange (national-scale impact and response), and red (major disaster, necessitating international response). Corresponding fatality thresholds for yellow, orange, and red alert levels are 1, 100, and 1000, respectively. For damage impact, yellow, orange, and red thresholds are triggered by estimated losses exceeding 1M, 10M, and $1B, respectively. The rationale for a dual approach to earthquake alerting stems from the recognition that relatively high fatalities, injuries, and homelessness dominate in countries where vernacular building practices typically lend themselves to high collapse and casualty rates, and it is these impacts that set prioritization for international response. In contrast, it is often financial and overall societal impacts that trigger the level of response in regions or countries where prevalent earthquake resistant construction practices greatly reduce building collapse and associated fatalities. Any newly devised alert protocols, whether financial or casualty based, must be intuitive and consistent with established lexicons and procedures. In this analysis, we make an attempt

  17. A New Tomato Hybrid 'Jinpeng M6' with Resistance to Meloidogyne incognita%抗南方根结线虫番茄新品种‘金棚M6

    Institute of Scientific and Technical Information of China (English)

    李晓东; 郑丽芳; 王建人; 巩振辉; 蔡义勇; 李永宁; 任向辉


    ‘金棚M6’番茄是以‘M6’为母本,‘13B’为父本杂交培育的无限生长类型一代杂种。植株生长势较强,叶片较稀。果实高圆形,幼果无绿肩。成熟果粉红色,无棱沟,着色均匀一致,光泽度好。果肉厚,果实硬度好,耐贮耐运,货架期长。高抗南方根结线虫,高抗番茄花叶病毒(ToMV),中抗黄瓜花叶病毒(CMV),抗枯萎病和叶霉病。适宜日光温室、大棚等保护地春提早、越冬及秋冬春一大茬栽培。早熟,春提早种植前期产量可达52500kg·hm-2,春季栽培总产量一般为127500-150000kg·hm-2。%'Jinpeng M6' is a new indeterminate growth type and pink tomato hybrid, which is developed by crossing 'M6' x ' 13B' . The hybrid grows strongly and has spare foliage. Fruits are highly round in shape, and young fruits have no green shoulder. Its matured fruit is pink, has a smooth peel, uniform colour and high glossiness. The fruit has thick pulp, big fruit core, long storability and shelf-life. The hybrid is highly resistant to Meloidogyne incognita and ToMV, moderately resistant to CMV, fusarium wilt and leaf mould. It is suitable for cultivation in early spring, overwinter and one big crop of autumn-winter-spring under greenhouse conditions. It is early ripening, the early yield is 52 500 kg · hm-2 in early spring, the total yield is about 127 500 - 150 000 kg·hm-2 in spring.

  18. Calibration and validation of earthquake catastrophe models. Case study: Impact Forecasting Earthquake Model for Algeria (United States)

    Trendafiloski, G.; Gaspa Rebull, O.; Ewing, C.; Podlaha, A.; Magee, B.


    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

  19. Estimates of aseismic slip associated with small earthquakes near San Juan Bautista, CA (United States)

    Hawthorne, J. C.; Simons, M.; Ampuero, J.-P.


    Postseismic slip observed after large (M > 6) earthquakes typically has an equivalent moment of a few tens of percent of the coseismic moment. Some observations of the recurrence intervals of repeating earthquakes suggest that postseismic slip following small (M≲4) earthquakes could be much larger—up to 10 or 100 times the coseismic moment. We use borehole strain data from U.S. Geological Survey strainmeter SJT to analyze deformation in the days before and after 1000 1.9 < M < 5 earthquakes near San Juan Bautista, CA. We find that on average, postseismic strain is roughly equal in magnitude to coseismic strain for the magnitude range considered, suggesting that postseismic moment following these small earthquakes is roughly equal to coseismic moment. This postseismic to coseismic moment ratio is larger than typically observed in earthquakes that rupture through the seismogenic zone but is much smaller than was hypothesized from modeling repeating earthquakes. Our results are consistent with a simple, self-similar model of earthquakes.

  20. Computing Earthquake Probabilities on Global Scales (United States)

    Holliday, James R.; Graves, William R.; Rundle, John B.; Turcotte, Donald L.


    Large devastating events in systems such as earthquakes, typhoons, market crashes, electricity grid blackouts, floods, droughts, wars and conflicts, and landslides can be unexpected and devastating. Events in many of these systems display frequency-size statistics that are power laws. Previously, we presented a new method for calculating probabilities for large events in systems such as these. This method counts the number of small events since the last large event and then converts this count into a probability by using a Weibull probability law. We applied this method to the calculation of large earthquake probabilities in California-Nevada, USA. In that study, we considered a fixed geographic region and assumed that all earthquakes within that region, large magnitudes as well as small, were perfectly correlated. In the present article, we extend this model to systems in which the events have a finite correlation length. We modify our previous results by employing the correlation function for near mean field systems having long-range interactions, an example of which is earthquakes and elastic interactions. We then construct an application of the method and show examples of computed earthquake probabilities.

  1. The M7 October 21, 1868 Hayward Earthquake, Northern California-140 Years Later (United States)

    Brocher, T. M.; Boatwright, J.; Lienkaemper, J. J.; Schwartz, D. P.; Garcia, S.


    October 21, 2008 marks the 140th anniversary of the M7 1868 Hayward earthquake. This large earthquake, which occurred slightly before 8 AM, caused extensive damage to San Francisco Bay Area and remains the nation's 12th most lethal earthquake. Property loss was extensive and about 30 people were killed. This earthquake culminated a decade-long series of earthquakes in the Bay Area which started with an M~6 earthquake in the southern Peninsula in 1856, followed by a series of four M5.8 to M6.1 sized earthquakes along the northern Calaveras fault, and ended with a M~6.5 earthquake in the Santa Cruz Mountains in 1865. Despite this flurry of quakes, the shaking from the 1868 earthquake was the strongest that the new towns and growing cities of the Bay Area had ever experienced. The effect on the brick buildings of the time was devastating: walls collapsed in San Francisco, Oakland, and San Jose, and buildings cracked as far away as Napa, Santa Rosa, and Hollister. The area that was strongly shaken (at Modified Mercalli Intensity VII or higher) encompassed about 2,300 km2. Aftershocks continued into November 1868. Surface cracking of the ground along the southern end of the Hayward Fault was traced from Warm Springs in Fremont northward 32 km to San Leandro. As Lawson (1908) reports, "the evidence to the northward of San Leandro is not very satisfactory. The country was then unsettled, and the information consisted of reports of cow- boys riding on the range". Analysis of historical triangulation data suggest that the fault moved as far north as Berkeley, and from these data the average slip along the fault is inferred to be about 1.9 ± 0.4 meters. The paleoseismic record from the southern end of the Hayward Fault provides evidence for 10 earthquakes before 1868. The average interval between these earthquakes is 170 ± 80 years, but the last five earthquakes have had an average interval of only 140 ± 50 years. The 1868 Hayward earthquake and more recent analogs such

  2. Inter-Disciplinary Validation of Pre Earthquake Signals. Case Study for Major Earthquakes in Asia (2004-2010) and for 2011 Tohoku Earthquake (United States)

    Ouzounov, D.; Pulinets, S.; Hattori, K.; Liu, J.-Y.; Yang. T. Y.; Parrot, M.; Kafatos, M.; Taylor, P.


    We carried out multi-sensors observations in our investigation of phenomena preceding major earthquakes. Our approach is based on a systematic analysis of several physical and environmental parameters, which we found, associated with the earthquake processes: thermal infrared radiation, temperature and concentration of electrons in the ionosphere, radon/ion activities, and air temperature/humidity in the atmosphere. We used satellite and ground observations and interpreted them with the Lithosphere-Atmosphere- Ionosphere Coupling (LAIC) model, one of possible paradigms we study and support. We made two independent continues hind-cast investigations in Taiwan and Japan for total of 102 earthquakes (M>6) occurring from 2004-2011. We analyzed: (1) ionospheric electromagnetic radiation, plasma and energetic electron measurements from DEMETER (2) emitted long-wavelength radiation (OLR) from NOAA/AVHRR and NASA/EOS; (3) radon/ion variations (in situ data); and 4) GPS Total Electron Content (TEC) measurements collected from space and ground based observations. This joint analysis of ground and satellite data has shown that one to six (or more) days prior to the largest earthquakes there were anomalies in all of the analyzed physical observations. For the latest March 11 , 2011 Tohoku earthquake, our analysis shows again the same relationship between several independent observations characterizing the lithosphere /atmosphere coupling. On March 7th we found a rapid increase of emitted infrared radiation observed from satellite data and subsequently an anomaly developed near the epicenter. The GPS/TEC data indicated an increase and variation in electron density reaching a maximum value on March 8. Beginning from this day we confirmed an abnormal TEC variation over the epicenter in the lower ionosphere. These findings revealed the existence of atmospheric and ionospheric phenomena occurring prior to the 2011 Tohoku earthquake, which indicated new evidence of a distinct

  3. An Atlas of ShakeMaps for Selected Global Earthquakes (United States)

    Allen, Trevor I.; Wald, David J.; Hotovec, Alicia J.; Lin, Kuo-Wan; Earle, Paul S.; Marano, Kristin D.


    An atlas of maps of peak ground motions and intensity 'ShakeMaps' has been developed for almost 5,000 recent and historical global earthquakes. These maps are produced using established ShakeMap methodology (Wald and others, 1999c; Wald and others, 2005) and constraints from macroseismic intensity data, instrumental ground motions, regional topographically-based site amplifications, and published earthquake-rupture models. Applying the ShakeMap methodology allows a consistent approach to combine point observations with ground-motion predictions to produce descriptions of peak ground motions and intensity for each event. We also calculate an estimated ground-motion uncertainty grid for each earthquake. The Atlas of ShakeMaps provides a consistent and quantitative description of the distribution and intensity of shaking for recent global earthquakes (1973-2007) as well as selected historic events. As such, the Atlas was developed specifically for calibrating global earthquake loss estimation methodologies to be used in the U.S. Geological Survey Prompt Assessment of Global Earthquakes for Response (PAGER) Project. PAGER will employ these loss models to rapidly estimate the impact of global earthquakes as part of the USGS National Earthquake Information Center's earthquake-response protocol. The development of the Atlas of ShakeMaps has also led to several key improvements to the Global ShakeMap system. The key upgrades include: addition of uncertainties in the ground motion mapping, introduction of modern ground-motion prediction equations, improved estimates of global seismic-site conditions (VS30), and improved definition of stable continental region polygons. Finally, we have merged all of the ShakeMaps in the Atlas to provide a global perspective of earthquake ground shaking for the past 35 years, allowing comparison with probabilistic hazard maps. The online Atlas and supporting databases can be found at

  4. From Multi-Sensors Observations Towards Cross-Disciplinary Study of Pre-Earthquake Signals. What have We Learned from the Tohoku Earthquake? (United States)

    Ouzounov, D.; Pulinets, S.; Papadopoulos, G.; Kunitsyn, V.; Nesterov, I.; Hayakawa, M.; Mogi, K.; Hattori, K.; Kafatos, M.; Taylor, P.


    The lessons we have learned from the Great Tohoku EQ (Japan, 2011) how this knowledge will affect our future observation and analysis is the main focus of this presentation.We present multi-sensors observations and multidisciplinary research in our investigation of phenomena preceding major earthquakes. These observations revealed the existence of atmospheric and ionospheric phenomena occurring prior to theM9.0 Tohoku earthquake of March 11, 2011, which indicates s new evidence of a distinct coupling between the lithosphere and atmosphere/ionosphere, as related to underlying tectonic activity. Similar results have been reported before the catastrophic events in Chile (M8.8, 2010), Italy (M6.3, 2009) and Sumatra (M9.3, 2004). For the Tohoku earthquake, our analysis shows a synergy between several independent observations characterizing the state of the lithosphere /atmosphere coupling several days before the onset of the earthquakes, namely: (i) Foreshock sequence change (rate, space and time); (ii) Outgoing Long wave Radiation (OLR) measured at the top of the atmosphere; and (iii) Anomalous variations of ionospheric parameters revealed by multi-sensors observations. We are presenting a cross-disciplinary analysis of the observed pre-earthquake anomalies and will discuss current research in the detection of these signals in Japan. We expect that our analysis will shed light on the underlying physics of pre-earthquake signals associated with some of the largest earthquake events

  5. High Performance Liquid Chromatography of Propellants. Part 1. Analysis of M1, M6, and M10 Propellants (United States)


    High performance liquid chromatography permits the differentation among the stabilizers and their degradation products together with accurate quantitation. This progress report describes work carried out in the analysis of single base propellants containing diphenylamine (DPA) as the stabilizer. Several degradation products have been identified and the routine determination of these compounds is feasible. The degradation of DPA seems to follow a pattern that is unique for M1 and M6’s as compared to the pattern for M10’s. It is postulated

  6. The 2010 Canterbury Earthquake: Curriculum Shockwaves (United States)

    Taylor, Mike; Moeed, Azra


    This paper reports data from an exploratory questionnaire designed to capture "curriculum P-waves"--those curriculum responses that were the fastest and therefore measured first--following a significant earthquake in New Zealand. As well as taking a professional interest in a major disaster in their backyard, it is assumed that social science and…

  7. The 2010 Canterbury Earthquake: Curriculum Shockwaves (United States)

    Taylor, Mike; Moeed, Azra


    This paper reports data from an exploratory questionnaire designed to capture "curriculum P-waves"--those curriculum responses that were the fastest and therefore measured first--following a significant earthquake in New Zealand. As well as taking a professional interest in a major disaster in their backyard, it is assumed that social…

  8. The 2010 Canterbury Earthquake: Curriculum Shockwaves (United States)

    Taylor, Mike; Moeed, Azra


    This paper reports data from an exploratory questionnaire designed to capture "curriculum P-waves"--those curriculum responses that were the fastest and therefore measured first--following a significant earthquake in New Zealand. As well as taking a professional interest in a major disaster in their backyard, it is assumed that social…

  9. Earthquake number forecasts testing (United States)

    Kagan, Yan Y.


    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

  10. Earthquake impact scale (United States)

    Wald, D.J.; Jaiswal, K.S.; Marano, K.D.; Bausch, D.


    With the advent of the USGS prompt assessment of global earthquakes for response (PAGER) system, which rapidly assesses earthquake impacts, U.S. and international earthquake responders are reconsidering their automatic alert and activation levels and response procedures. To help facilitate rapid and appropriate earthquake response, an Earthquake Impact Scale (EIS) is proposed on the basis of two complementary criteria. On the basis of the estimated cost of damage, one is most suitable for domestic events; the other, on the basis of estimated ranges of fatalities, is generally more appropriate for global events, particularly in developing countries. Simple thresholds, derived from the systematic analysis of past earthquake impact and associated response levels, are quite effective in communicating predicted impact and response needed after an event through alerts of green (little or no impact), yellow (regional impact and response), orange (national-scale impact and response), and red (international response). Corresponding fatality thresholds for yellow, orange, and red alert levels are 1, 100, and 1,000, respectively. For damage impact, yellow, orange, and red thresholds are triggered by estimated losses reaching $1M, $100M, and $1B, respectively. The rationale for a dual approach to earthquake alerting stems from the recognition that relatively high fatalities, injuries, and homelessness predominate in countries in which local building practices typically lend themselves to high collapse and casualty rates, and these impacts lend to prioritization for international response. In contrast, financial and overall societal impacts often trigger the level of response in regions or countries in which prevalent earthquake resistant construction practices greatly reduce building collapse and resulting fatalities. Any newly devised alert, whether economic- or casualty-based, should be intuitive and consistent with established lexicons and procedures. Useful alerts should

  11. Near-shore Evaluation of Holocene Faulting and Earthquake Hazard in the New York City Metropolitan Region (United States)

    Cormier, M. H.; King, J. W.; Seeber, L.; Heil, C. W., Jr.; Caccioppoli, B.


    During its relatively short historic period, the Atlantic Seaboard of North America has experienced a few M6+ earthquakes. These events raise the specter of a similar earthquake occurring anywhere along the eastern seaboard, including in the greater New York City (NYC) metropolitan area. Indeed, the NYC Seismic Zone is one of several concentrations of earthquake activity that stand out in the field of epicenters over eastern North America. Various lines of evidence point to a maximum magnitude in the M7 range for metropolitan NYC - a dramatic scenario that is counterbalanced by the low probability of such an event. Several faults mapped near NYC strike NW, sub-normal to the NE-striking structural trends of the Appalachians, and all earthquake sequences with well-established fault sources in the NYC seismic zone originate from NW-striking faults. With funding from the USGS Earthquake Hazard Program, we recently (July 2016) collected 85 km of high-resolution sub-bottom (CHIRP) profiles along the north shore of western Long Island Sound, immediately adjacent to metropolitan NYC. This survey area is characterized by a smooth, 15.5 kyr-old erosional surface and overlying strata with small original relief. CHIRP sonar profiles of these reflectors are expected to resolve fault or fold-related vertical relief (if present) greater than 50 cm. They would also resolve horizontal fault displacements with similar resolution, as may be expressed by offsets of either sedimentary or geomorphic features. No sedimentary cover on the land portion of the metro area offers such ideal reference surfaces, which are continuous in both time and space. Seismic profiles have a spacing of 200 m and have been acquired mostly perpendicular to the NW-striking faults mapped on land. These new data will be analyzed systematically for all resolvable features and then interpreted, distinguishing sedimentary, geomorphic, and tectonic features. The absence of evidence of post-glacial tectonic

  12. The 2014 Mw6.2 Eketahuna earthquake, Hikurangi subduction zone - normal faulting in the subducted Pacific Plate crust (United States)

    Abercrombie, R. E.; Bannister, S. C.; Francois-Holden, C.; Hamling, I. J.; Ristau, J. P.


    The 2014 January 20th M6.2 Eketahuna earthquake occurred in the subducted crust of the Pacific plate at the Hikurangi subduction zone, beneath North Island, New Zealand. Moment tensor analysis together with aftershock relocations show that this event was an oblique-normal faulting intraplate event, with hypocentre depth ca.30 km, and with rupture on a northwest-dipping fault extending through the subducted crust up to the subduction megathrust at ca.18-20 km depth. More than 3500 aftershocks were subsequently recorded by the New Zealand GeoNet network, with only minor migration of the aftershocks away from the inferred mainshock rupture, and with very few aftershocks within +/- 1 km of the subduction megathrust. The megathrust in this particular region is inferred to be interseismically locked with no seismic or aseismic slip, although slow slip is occurring ca.15-30 km down-dip (Wallace et al, 2013). Similar oblique-normal faulting events have previously occurred along the Hikurangi subduction margin, including in 1985 (ML5.7) and 1990 (Mw6.2). Earlier earthquakes in 1942 (Mw6.8) and 1921 (Mw6.8) are also inferred to have occurred at a similar depth within the subducted crust. The 1990 earthquake sequence occurred ~40 km along-strike from the 2014 Eketahuna event, and involved a Mw6.2 oblique-normal faulting event in the subducted crust, which was quickly followed by a Mw6.4 event in the overlying crust, with both thrust and dextral strike-slip components, possibly responding to deeper aseismic slip. Deeper earthquakes of similar type at other subduction margins are thought to be high stress drop. We calculate the stress drops of the mainshock and larger aftershocks, using a direct wave, empirical Green's function (EGF) approach that includes measurement uncertainties and objective criteria for assessing the quality of each spectral ratio (Abercrombie, 2013). We compare the results to those for earthquakes in other tectonic regions of New Zealand, calculated using

  13. Rupture, waves and earthquakes (United States)

    UENISHI, Koji


    Normally, an earthquake is considered as a phenomenon of wave energy radiation by rupture (fracture) of solid Earth. However, the physics of dynamic process around seismic sources, which may play a crucial role in the occurrence of earthquakes and generation of strong waves, has not been fully understood yet. Instead, much of former investigation in seismology evaluated earthquake characteristics in terms of kinematics that does not directly treat such dynamic aspects and usually excludes the influence of high-frequency wave components over 1 Hz. There are countless valuable research outcomes obtained through this kinematics-based approach, but “extraordinary” phenomena that are difficult to be explained by this conventional description have been found, for instance, on the occasion of the 1995 Hyogo-ken Nanbu, Japan, earthquake, and more detailed study on rupture and wave dynamics, namely, possible mechanical characteristics of (1) rupture development around seismic sources, (2) earthquake-induced structural failures and (3) wave interaction that connects rupture (1) and failures (2), would be indispensable. PMID:28077808

  14. Earthquake engineering in China

    Institute of Scientific and Technical Information of China (English)



    The development of earthquake engineering in China is described into three stages.The initial stage in 1950's -1960's was marked with the initiation of this branch of science from its creation in the first national 12-year plan of science andtechnology by specifying earthquake engineering as a branch item and IEM was one participant. The first earthquake zonationmap and the first seismic design code were soon completed and used in engineering design. Site effect on structural design andsite selection were seriously studied. The second stage marked with the occurrence of quite a few strong earthquakes in China,from which many lessons were learned and corresponding considerations were specified in our design codes and followed inconstruction practice. The third stage is a stage of disaster management, which is marked by a series of governmentdocumentations, leading by a national law of the People's Republic of China on the protecting against and mitigating earthquakedisasters adopted at the meeting of the Standing Committee of the National People's Congress of the People's Republic of Chinain 1997, and then followed by some provincial and municipal laws to force the actions outlined in the national law. It may beexpected that our society will be much more safer to resist the attack of future strong earthquakes with less losses. Lastly,possible future developments are also discussed.

  15. Rupture, waves and earthquakes. (United States)

    Uenishi, Koji


    Normally, an earthquake is considered as a phenomenon of wave energy radiation by rupture (fracture) of solid Earth. However, the physics of dynamic process around seismic sources, which may play a crucial role in the occurrence of earthquakes and generation of strong waves, has not been fully understood yet. Instead, much of former investigation in seismology evaluated earthquake characteristics in terms of kinematics that does not directly treat such dynamic aspects and usually excludes the influence of high-frequency wave components over 1 Hz. There are countless valuable research outcomes obtained through this kinematics-based approach, but "extraordinary" phenomena that are difficult to be explained by this conventional description have been found, for instance, on the occasion of the 1995 Hyogo-ken Nanbu, Japan, earthquake, and more detailed study on rupture and wave dynamics, namely, possible mechanical characteristics of (1) rupture development around seismic sources, (2) earthquake-induced structural failures and (3) wave interaction that connects rupture (1) and failures (2), would be indispensable.

  16. Recurrence Statistics of Great Earthquakes

    CERN Document Server

    Ben-Naim, E; Johnson, P A


    We investigate the sequence of great earthquakes over the past century. To examine whether the earthquake record includes temporal clustering, we identify aftershocks and remove those from the record. We focus on the recurrence time, defined as the time between two consecutive earthquakes. We study the variance in the recurrence time and the maximal recurrence time. Using these quantities, we compare the earthquake record with sequences of random events, generated by numerical simulations, while systematically varying the minimal earthquake magnitude Mmin. Our analysis shows that the earthquake record is consistent with a random process for magnitude thresholds 7.0<=Mmin<=8.3, where the number of events is larger. Interestingly, the earthquake record deviates from a random process at magnitude threshold 8.4<=Mmin<= 8.5, where the number of events is smaller; however, this deviation is not strong enough to conclude that great earthquakes are clustered. Overall, the findings are robust both qualitat...

  17. Earthquake Damage to Transportation Systems (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Earthquakes represent one of the most destructive natural hazards known to man. A serious result of large-magnitude earthquakes is the disruption of transportation...

  18. Earthquakes, March-April 1989 (United States)

    Person, W.J.


    The first major earthquake (7.0-7.9) of the year hit Mexico on April 25, killing three people and causing some damage. Earthquake-related deaths were also reported from Malawi, China, and New Britain. 

  19. Early earthquakes of the Americas

    Institute of Scientific and Technical Information of China (English)

    Niu Zhijun


    @@ In recent decades the science of seismology,in particular the study of individual earthquakes, has expanded dramatically. A seismologist can look for evidence of past earthquakes in the material remains that have been excavated by archaeologists.

  20. Relationship between marine mammal stranding events and offshore earthquakes (United States)

    Grant, Rachel; Savirina, Anna; Hoppit, Will


    The causes of marine mammal stranding events are largely unknown, but may relate to ocean currents, severe weather, anthropogenic noise pollution, and other factors. Large stranding events have been suggested to occur as a result of offshore earthquakes but there is little evidence as yet to support this hypothesis. Stranding events occur in hotspots, which are sometimes areas of high seismic activity, such as Taiwan, and other times, in areas that are removed from seismic zones, such as Cape Cod. We analyse a large and robust dataset of marine mammal stranding data collected off the coast of Washington and Oregon from 1999 to 2010, to look for statistical connections to offshore earthquakes. We looked forward, as well as backward in time from significant seismic events, to ascertain whether stranding occurrences, if connected to earthquakes, are a result of the earthquake preparation period or the earthquake itself. Possible mechanisms are discussed.

  1. AthMethPre: a web server for the prediction and query of mRNA m(6)A sites in Arabidopsis thaliana. (United States)

    Xiang, Shunian; Yan, Zhangming; Liu, Ke; Zhang, Yaou; Sun, Zhirong


    N(6)-Methyladenosine (m(6)A) is the most prevalent and abundant modification in mRNA that has been linked to many key biological processes. High-throughput experiments have generated m(6)A-peaks across the transcriptome of A. thaliana, but the specific methylated sites were not assigned, which impedes the understanding of m(6)A functions in plants. Therefore, computational prediction of mRNA m(6)A sites becomes emergently important. Here, we present a method to predict the m(6)A sites for A. thaliana mRNA sequence(s). To predict the m(6)A sites of an mRNA sequence, we employed the support vector machine to build a classifier using the features of the positional flanking nucleotide sequence and position-independent k-mer nucleotide spectrum. Our method achieved good performance and was applied to a web server to provide service for the prediction of A. thaliana m(6)A sites. The server also provides a comprehensive database of predicted transcriptome-wide m(6)A sites and curated m(6)A-seq peaks from the literature for query and visualization. The AthMethPre web server is the first web server that provides a user-friendly tool for the prediction and query of A. thaliana mRNA m(6)A sites, which is freely accessible for public use at .

  2. Understanding Earthquake Hazard & Disaster in Himalaya - A Perspective on Earthquake Forecast in Himalayan Region of South Central Tibet (United States)

    Shanker, D.; Paudyal, ,; Singh, H.


    characterized by an extremely high annual earthquake frequency as compared to the preceding normal and the following gap episodes, and is the characteristics of the events in such an episode is causally related with the magnitude and the time of occurrence of the forthcoming earthquake. It is observed here that for the shorter duration of the preparatory time period, there will be the smaller mainshock, and vice-versa. The Western Nepal and the adjoining Tibet region are potential for the future medium size earthquakes. Accordingly, it has been estimated here that an earthquake with M 6.5 ± 0.5 may occur at any time from now onwards till December 2011 in the Western Nepal within an area bounded by 29.3°-30.5° N and 81.2°-81.9° E, in the focal depth range 10 -30 km.

  3. Correlating precursory declines in groundwater radon with earthquake magnitude. (United States)

    Kuo, T


    Both studies at the Antung hot spring in eastern Taiwan and at the Paihe spring in southern Taiwan confirm that groundwater radon can be a consistent tracer for strain changes in the crust preceding an earthquake when observed in a low-porosity fractured aquifer surrounded by a ductile formation. Recurrent anomalous declines in groundwater radon were observed at the Antung D1 monitoring well in eastern Taiwan prior to the five earthquakes of magnitude (Mw ): 6.8, 6.1, 5.9, 5.4, and 5.0 that occurred on December 10, 2003; April 1, 2006; April 15, 2006; February 17, 2008; and July 12, 2011, respectively. For earthquakes occurring on the longitudinal valley fault in eastern Taiwan, the observed radon minima decrease as the earthquake magnitude increases. The above correlation has been proven to be useful for early warning local large earthquakes. In southern Taiwan, radon anomalous declines prior to the 2010 Mw 6.3 Jiasian, 2012 Mw 5.9 Wutai, and 2012 ML 5.4 Kaohsiung earthquakes were also recorded at the Paihe spring. For earthquakes occurring on different faults in southern Taiwan, the correlation between the observed radon minima and the earthquake magnitude is not yet possible. © 2013, National Ground Water Association.

  4. An efficient repeating signal detector to investigate earthquake swarms (United States)

    Skoumal, Robert J.; Brudzinski, Michael R.; Currie, Brian S.


    Repetitive earthquake swarms have been recognized as key signatures in fluid injection induced seismicity, precursors to volcanic eruptions, and slow slip events preceding megathrust earthquakes. We investigate earthquake swarms by developing a Repeating Signal Detector (RSD), a computationally efficient algorithm utilizing agglomerative clustering to identify similar waveforms buried in years of seismic recordings using a single seismometer. Instead of relying on existing earthquake catalogs of larger earthquakes, RSD identifies characteristic repetitive waveforms by rapidly identifying signals of interest above a low signal-to-noise ratio and then grouping based on spectral and time domain characteristics, resulting in dramatically shorter processing time than more exhaustive autocorrelation approaches. We investigate seismicity in four regions using RSD: (1) volcanic seismicity at Mammoth Mountain, California, (2) subduction-related seismicity in Oaxaca, Mexico, (3) induced seismicity in Central Alberta, Canada, and (4) induced seismicity in Harrison County, Ohio. In each case, RSD detects a similar or larger number of earthquakes than existing catalogs created using more time intensive methods. In Harrison County, RSD identifies 18 seismic sequences that correlate temporally and spatially to separate hydraulic fracturing operations, 15 of which were previously unreported. RSD utilizes a single seismometer for earthquake detection which enables seismicity to be quickly identified in poorly instrumented regions at the expense of relying on another method to locate the new detections. Due to the smaller computation overhead and success at distances up to ~50 km, RSD is well suited for real-time detection of low-magnitude earthquake swarms with permanent regional networks.

  5. Australia: historical earthquake studies

    Directory of Open Access Journals (Sweden)

    K. McCue


    Full Text Available Historical studies of earthquakes in Australia using information dating back to 1788 have been comprehensive, if not exhaustive. Newspapers have been the main source of historical earthquake studies. A brief review is given here with an introduction to the pre-European aboriginal dreamtime information. Some of the anecdotal information of the last two centuries has been compiled as isoseismal maps. Relationships between isoseismal radii and magnitude have been established using post-instrumental data allowing magnitudes to be assigned to the pre-instrumental data, which can then be incorporated into the national earthquake database. The studies have contributed to hazard analyses for the building codes and stimulated research into microzonation and paleo-seismology.

  6. Unusual geologic evidence of coeval seismic shaking and tsunamis shows variability in earthquake size and recurrence in the area of the giant 1960 Chile earthquake (United States)

    Cisternas, M; Garrett, E; Wesson, Robert L.; Dura, T.; Ely, L. L


    An uncommon coastal sedimentary record combines evidence for seismic shaking and coincident tsunami inundation since AD 1000 in the region of the largest earthquake recorded instrumentally: the giant 1960 southern Chile earthquake (Mw 9.5). The record reveals significant variability in the size and recurrence of megathrust earthquakes and ensuing tsunamis along this part of the Nazca-South American plate boundary. A 500-m long coastal outcrop on Isla Chiloé, midway along the 1960 rupture, provides continuous exposure of soil horizons buried locally by debris-flow diamicts and extensively by tsunami sand sheets. The diamicts flattened plants that yield geologically precise ages to correlate with well-dated evidence elsewhere. The 1960 event was preceded by three earthquakes that probably resembled it in their effects, in AD 898 - 1128, 1300 - 1398 and 1575, and by five relatively smaller intervening earthquakes. Earthquakes and tsunamis recurred exceptionally often between AD 1300 and 1575. Their average recurrence interval of 85 years only slightly exceeds the time already elapsed since 1960. This inference is of serious concern because no earthquake has been anticipated in the region so soon after the 1960 event, and current plate locking suggests that some segments of the boundary are already capable of producing large earthquakes. This long-term earthquake and tsunami history of one of the world's most seismically active subduction zones provides an example of variable rupture mode, in which earthquake size and recurrence interval vary from one earthquake to the next.

  7. Anomalies in Water Level Records in Yunnan Caused by the Great Indonesian Earthquakes and Their Significance

    Institute of Scientific and Technical Information of China (English)

    Fu Hong; Wu Chengdong; Liu Qiang; Wang Shiqin; Chen Yan


    Two great earthquakes occurred in the sea northwest of Sumatra,Indonesia,on December 26,2004 and March 29,2005.The observation of water levels in Yunnan yielded abundant information about the two earthquakes.This paper presents the water level response to the two earthquakes in Yunnan and makes a preliminary analysis.It is observed that the large earthquake-induced abnormal water level change could be better recorded by analog recording than by digital recording.The large earthquake-caused water level rise or decline may be attributed to the effect of seismic waves that change the stress in tectonic units,and is correlated with the geological structure where the well is located.The water level response mode in a well is totally the same for earthquakes occurring on the same fault and with the same fracture mode.The only difference is that the response amplitude increases with the growth of the earthquake magnitude.

  8. Organizational changes at Earthquakes & Volcanoes (United States)

    Gordon, David W.


    Primary responsibility for the preparation of Earthquakes & Volcanoes within the Geological Survey has shifted from the Office of Scientific Publications to the Office of Earthquakes, Volcanoes, and Engineering (OEVE). As a consequence of this reorganization, Henry Spall has stepepd down as Science Editor for Earthquakes & Volcanoes(E&V).

  9. Sensing the earthquake (United States)

    Bichisao, Marta; Stallone, Angela


    Making science visual plays a crucial role in the process of building knowledge. In this view, art can considerably facilitate the representation of the scientific content, by offering a different perspective on how a specific problem could be approached. Here we explore the possibility of presenting the earthquake process through visual dance. From a choreographer's point of view, the focus is always on the dynamic relationships between moving objects. The observed spatial patterns (coincidences, repetitions, double and rhythmic configurations) suggest how objects organize themselves in the environment and what are the principles underlying that organization. The identified set of rules is then implemented as a basis for the creation of a complex rhythmic and visual dance system. Recently, scientists have turned seismic waves into sound and animations, introducing the possibility of "feeling" the earthquakes. We try to implement these results into a choreographic model with the aim to convert earthquake sound to a visual dance system, which could return a transmedia representation of the earthquake process. In particular, we focus on a possible method to translate and transfer the metric language of seismic sound and animations into body language. The objective is to involve the audience into a multisensory exploration of the earthquake phenomenon, through the stimulation of the hearing, eyesight and perception of the movements (neuromotor system). In essence, the main goal of this work is to develop a method for a simultaneous visual and auditory representation of a seismic event by means of a structured choreographic model. This artistic representation could provide an original entryway into the physics of earthquakes.

  10. Incorporating human-triggered earthquake risks into energy and water policies (United States)

    Klose, C. D.; Seeber, L.; Jacob, K. H.


    A comprehensive understanding of earthquake risks in urbanized regions requires an accurate assessment of both urban vulnerabilities and hazards from earthquakes, including ones whose timing might be affected by human activities. Socioeconomic risks associated with human-triggered earthquakes are often misconstrued and receive little scientific, legal, and public attention. Worldwide, more than 200 damaging earthquakes, associated with industrialization and urbanization, were documented since the 20th century. Geomechanical pollution due to large-scale geoengineering activities can advance the clock of earthquakes, trigger new seismic events or even shot down natural background seismicity. Activities include mining, hydrocarbon production, fluid injections, water reservoir impoundments and deep-well geothermal energy production. This type of geohazard has impacts on human security on a regional and national level. Some planned or considered future engineering projects raise particularly strong concerns about triggered earthquakes, such as for instance, sequestration of carbon dioxide by injecting it deep underground and large-scale natural gas production in the Marcellus shale in the Appalacian basin. Worldwide examples of earthquakes are discussed, including their associated losses of human life and monetary losses (e.g., 1989 Newcastle and Volkershausen earthquakes, 2001 Killari earthquake, 2006 Basel earthquake, 2010 Wenchuan earthquake). An overview is given on global statistics of human-triggered earthquakes, including depths and time delay of triggering. Lastly, strategies are described, including risk mitigation measures such as urban planning adaptations and seismic hazard mapping.

  11. Impending HRT wave precursors to the Wenchuan M_s8.0 earthquake and methods of earthquake impending prediction by using HRT wave

    Institute of Scientific and Technical Information of China (English)


    . Thereafter, we have captured HRT waves from more than twenty strong earthquakes, which are well-matched and show repeatability, consistency and regularity. All our observation with the HRT waves demonstrate that HRT wave precursors to earthquakes indeed exist. Strong earthquakes can be predicted and short-term and impending earthquake prediction is achievable in the very near future. From all the observations, including the ones at HG station from Wenchuan Ms8.0 earthquake, we conclude that using HRT wave to predict earthquakes is feasible.

  12. Synchronization of atmospheric indicators at the last stage of earthquake preparation cycle

    Directory of Open Access Journals (Sweden)

    Sergey A. Pulinets


    Full Text Available We consider the dynamics of different parameters in the boundary layer of atmosphere and low level cloud structure around the time of three recent moderate and strong earthquakes: Virginia M 5.8 earthquake on August 23 2011 in USA, Van M 7.1 earthquake on October 23 2011 in Turkey, and Northwestern Iran M 6.4 earthquake on August 11, 2012, Iran. Using as indicators the water vapor chemical potential correction value, aerosol optical thickness, and linear cloud structures appearance we discovered their coherence in space and time within the time interval 3-5 days before the seismic shock. Obtained results are interpreted as synergetic result of the lithosphere-atmosphere-ionosphere coupling process.

  13. Marcellus Shale fracking waste caused earthquakes in Ohio (United States)

    Schultz, Colin


    Before January 2011, Youngstown, Ohio, had never had an earthquake since observations began in 1776. In December 2010 the Northstar 1 injection well came online; this well was built to pump wastewater produced by hydraulic fracturing projects in Pennsylvania into storage deep underground. In the year that followed, seismometers in and around Youngstown recorded 109 earthquakes—the strongest of the set being a magnitude 3.9 earthquake on 31 December 2011.

  14. Method to Determine Appropriate Source Models of Large Earthquakes Including Tsunami Earthquakes for Tsunami Early Warning in Central America (United States)

    Tanioka, Yuichiro; Miranda, Greyving Jose Arguello; Gusman, Aditya Riadi; Fujii, Yushiro


    Large earthquakes, such as the Mw 7.7 1992 Nicaragua earthquake, have occurred off the Pacific coasts of El Salvador and Nicaragua in Central America and have generated distractive tsunamis along these coasts. It is necessary to determine appropriate fault models before large tsunamis hit the coast. In this study, first, fault parameters were estimated from the W-phase inversion, and then an appropriate fault model was determined from the fault parameters and scaling relationships with a depth dependent rigidity. The method was tested for four large earthquakes, the 1992 Nicaragua tsunami earthquake (Mw7.7), the 2001 El Salvador earthquake (Mw7.7), the 2004 El Astillero earthquake (Mw7.0), and the 2012 El Salvador-Nicaragua earthquake (Mw7.3), which occurred off El Salvador and Nicaragua in Central America. The tsunami numerical simulations were carried out from the determined fault models. We found that the observed tsunami heights, run-up heights, and inundation areas were reasonably well explained by the computed ones. Therefore, our method for tsunami early warning purpose should work to estimate a fault model which reproduces tsunami heights near the coast of El Salvador and Nicaragua due to large earthquakes in the subduction zone.

  15. Daily earthquake forecasts during the May-June 2012 Emilia earthquake sequence (northern Italy

    Directory of Open Access Journals (Sweden)

    Warner Marzocchi


    Full Text Available On May 20, 2012, at 02:03 UTC, a magnitude Ml 5.9 earthquake hit part of the Po Plain area (latitude, 44.89 ˚N; longitude, 11.23 ˚E close to the village of Finale-Emilia in the Emilia-Romagna region (northern Italy. This caused a number of human losses and significant economic damage to buildings, and to local farms and industry. This earthquake was preceded by an increase in the seismicity the day before, with the largest shock of Ml 4.1 at 23:13 UTC (latitude, 44.90 ˚N; longitude, 11.26 ˚E. It was then followed by six other Ml 5.0 or greater events in the following weeks. The largest of these six earthquakes occurred on May 29, 2012, at 07:00 UTC (Ml 5.8, and was located 12 km southwest of the May 20, 2012, main event (latitude, 44.85 ˚N; longitude, 11.09 ˚E, resulting in the collapse of many buildings that had already been weakened, a greater number of victims, and most of the economic damage (see Figure 1. This sequence took place in one of the Italian regions that is considered to be at small-to-moderate seismic hazard [Gruppo di Lavoro MPS 2004]. Earthquakes of the M6 class have occurred in the past in this zone [Gruppo di Lavoro CPTI 2004], but with a much smaller time frequency with respect to the most seismically hazardous parts of Italy. […

  16. Seismic hazard and risks based on the Unified Scaling Law for Earthquakes (United States)

    Kossobokov, Vladimir; Nekrasova, Anastasia


    Losses from natural disasters continue to increase mainly due to poor understanding by majority of scientific community, decision makers and public, the three components of Risk, i.e., Hazard, Exposure, and Vulnerability. Contemporary Science is responsible for not coping with challenging changes of Exposures and their Vulnerability inflicted by growing population, its concentration, etc., which result in a steady increase of Losses from Natural Hazards. Scientists owe to Society for lack of knowledge, education, and communication. In fact, Contemporary Science can do a better job in disclosing Natural Hazards, assessing Risks, and delivering such knowledge in advance catastrophic events. Any kind of risk estimates R(g) at location g results from a convolution of the natural hazard H(g) with the exposed object under consideration O(g) along with its vulnerability V(O(g)). Note that g could be a point, or a line, or a cell on or under the Earth surface and that distribution of hazards, as well as objects of concern and their vulnerability, could be time-dependent. There exist many different risk estimates even if the same object of risk and the same hazard are involved. It may result from the different laws of convolution, as well as from different kinds of vulnerability of an object of risk under specific environments and conditions. Both conceptual issues must be resolved in a multidisciplinary problem oriented research performed by specialists in the fields of hazard, objects of risk, and object vulnerability, i.e. specialists in earthquake engineering, social sciences and economics. To illustrate this general concept, we first construct seismic hazard assessment maps based on the Unified Scaling Law for Earthquakes (USLE). The parameters A, B, and C of USLE, i.e. log N(M,L) = A - B•(M-6) + C•log L, where N(M,L) is the expected annual number of earthquakes of a certain magnitude M within an area of linear size L, are used to estimate the expected maximum

  17. Gas and Dust Phenomena of Mega-earthquakes and the Cause (United States)

    Yue, Z.


    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

  18. Historical Earthquakes and Active Structure for Georgia (United States)

    Tsereteli, Nino; Varazanashivli, Otar


    Long-term seismic history is an important foundation for reliable assessment of seismic hazard and risk. Therefore, completeness of earthquake catalogues in the longest historical part is very important. Survived historical sources, as well as special researches from the institutes, museums, libraries and archives in Georgia, the Caucasus and the Middle East indicate to high level of seismicity which entailed numerous human casualties and destruction on the territory of Georgia during the historical period. The study and detailed analysis of these original documents and researches have allowed us to create a new catalogue of historical earthquakes of Georgia from 1250 BC to 1900 AD. The method of the study is based on a multidisciplinary approach, i.e. on the joint use of methods of history and paleoseismology, archeoseismology, seismotectonics, geomorphology, etc. We present here a new parametric catalogue of 44 historic earthquakes of Georgia and a full "descriptor" of all the phenomena described in it. Constructed on its basis, the summarized map of the distribution of maximum damage in the historical period (before 1900) on the territory of Georgia clearly shows the main features of the seismic field during this period. In particular, in the axial part and the southern slope of the Greater Caucasus there is a seismic gap, which was filled in 1991 by the strongest earthquake and its aftershocks in Racha. In addition, it is also obvious that very high seismic activity in the central and eastern parts of the Javakheti highland is not described in historical materials and this fact requires further searches of various kinds of sources that contain data about historical earthquakes. We hope that this catalogue will enable to create a new joint (instrumental and historical) parametric earthquake catalogue of Georgia and will serve to assess the real seismic hazard and risk in the country.

  19. Photodynamic activities of silicon phthalocyanines against achromic M6 melanoma cells and healthy human melanocytes and keratinocytes. (United States)

    Decreau, R; Richard, M J; Verrando, P; Chanon, M; Julliard, M


    Dichlorosilicon phthalocyanine (Cl2SiPc) and bis(tri-n-hexylsiloxy) silicon phthalocyanine (HexSiPc) have been evaluated in vitro as potential photosensitizers for photodynamic therapy (PDT) against the human amelanotic melanoma cell line M6. Each photosensitizer is dissolved in a solvent-PBS mixture, or entrapped in egg-yolk lecithin liposomes or in Cremophor EL micelles. The cells are incubated for 1 h with the sensitizer and then irradiated for 20 min, 1 h or 2 h (lambda > 480 nm, 10 mW cm-2). The photocytotoxic effect is dependent on the photosensitizer concentration and the light dose. Higher phototoxicity is observed after an irradiation of 2 h: treatment with a solution of photosensitizer (2 x 10(-9) M) leads to 10% (HexSiPc in egg-yolk lecithin liposomes) or 20% (Cl2SiPc in DMF-PBS solution) cell viability. After 1 h incubation and 20 min of light exposure, the photodynamic effect is connected with the type of delivery system used. For HexSiPc, lower cell viability is found when this photosensitizer is entrapped in egg-yolk lecithin instead of solvent-PBS or for Cremophor EL micelles with Cl2SiPc. Liposome-delivered HexSiPc leads to lipid damage in M6 cells, illustrated by an increase of thiobarbituric acid-reacting substances (TBARs), but the change is not significant with Cremophor EL. The same is observed for the antioxidative defences after photodynamic stress. The cells irradiated with HexSiPc entrapped in liposomes display an increase of superoxide dismutase (SOD) activity and a decrease of glutathione (GSH) level, glutathione peroxidase (GSHPx) and catalase (Cat) activities.

  20. How did the earthquake early warning perform for the 2016 Kumamoto earthquakes? (United States)

    Yamada, M.; Nishimae, Y.


    The 2016 Kumamoto earthquakes are the sequence of two major earthquakes occurred in the Kumamoto, South part of Japan, in April 2016. The first earthquake occurred on April, 14 9:26pm with Mj6.5. The second and larger earthquake occurred 27 hours later, on April 16 1:25am with Mj 7.3. About 50 people were killed due to the collapse of housings and landslides. The Japan Meteorological Agency (JMA) properly provided earthquake early warnings (EEW) for both earthquakes: the warning for the April 14 earthquake was issued at 4 seconds after the first P-wave detection, which is 8 seconds after the origin time. The warning for the April 16 earthquake was issued at 4 seconds after the first P-arrival, and 8.5 seconds after the origin time. The blind zone where EEW was not provided before S-wave arrival is about 25km from the epicenter. This range of blind zone is expected for inland earthquakes whose S-P time is relatively short, so the EEW system worked properly as it was designed. The estimated magnitude was 6.5 and 6.9, respectively, when the warning was reported to public, so the performance of the accuracy and speed was satisfactory. The EEW provided other 17 warnings for smaller earthquakes in Kumamoto prefecture in April 2016. 80% of the warnings (14/17) predicted the seismic intensity within plus-minus 1. However, three events overestimated the seismic intensity by more than 1 unit, and two events underestimated the intensity by more than 1 unit. For the underestimated cases, the magnitude was estimated reasonably well with the error less than 0.3, which suggests this underestimation was due to the error in either attenuation relationship or subsurface soil amplification. For the overestimated cases, the magnitude was also overestimated, which suggests the source estimation had a significant error due to multiple aftershocks. We try to improve this performance to the aftershocks by applying the integrated particle filter approach to the JMA strong motion and Hi

  1. The 4 January 2016 Manipur earthquake in the Indo-Burmese wedge, an intra-slab event

    Directory of Open Access Journals (Sweden)

    V. K. Gahalaut


    Full Text Available Earthquakes in the Indo-Burmese wedge occur due to India-Sunda plate motion. These earthquakes generally occur at depth between 25 and 150 km and define an eastward gently dipping seismicity trend surface that coincides with the Indian slab. Although this feature mimics the subduction zone, the relative motion of Indian plate predominantly towards north, earthquake focal mechanisms suggest that these earthquakes are of intra-slab type which occur on steep plane within the Indian plate. The relative motion between the India and Sunda plates is accommodated at the Churachandpur-Mao fault (CMF and Sagaing Fault. The 4 January 2016 Manipur earthquake (M 6.7 is one such earthquake which occurred 20 km west of the CMF at ∼60 km depth. Fortunately, this earthquake occurred in a very sparse population region with very traditional wooden frame houses and hence, the damage caused by the earthquake in the source region was very minimal. However, in the neighbouring Imphal valley, it caused some damage to the buildings and loss of eight lives. The damage in Imphal valley due to this and historical earthquakes in the region emphasizes the role of local site effect in the Imphal valley.

  2. Indonesian Earthquake Decision Support System

    CERN Document Server

    Warnars, Spits


    Earthquake DSS is an information technology environment which can be used by government to sharpen, make faster and better the earthquake mitigation decision. Earthquake DSS can be delivered as E-government which is not only for government itself but in order to guarantee each citizen's rights for education, training and information about earthquake and how to overcome the earthquake. Knowledge can be managed for future use and would become mining by saving and maintain all the data and information about earthquake and earthquake mitigation in Indonesia. Using Web technology will enhance global access and easy to use. Datawarehouse as unNormalized database for multidimensional analysis will speed the query process and increase reports variation. Link with other Disaster DSS in one national disaster DSS, link with other government information system and international will enhance the knowledge and sharpen the reports.

  3. Episodic tremor triggers small earthquakes (United States)

    Balcerak, Ernie


    It has been suggested that episodic tremor and slip (ETS), the weak shaking not associated with measurable earthquakes, could trigger nearby earthquakes. However, this had not been confirmed until recently. Vidale et al. monitored seismicity in the 4-month period around a 16-day episode of episodic tremor and slip in March 2010 in the Cascadia region. They observed five small earthquakes within the subducting slab during the ETS episode. They found that the timing and locations of earthquakes near the tremor suggest that the tremor and earthquakes are related. Furthermore, they observed that the rate of earthquakes across the area was several times higher within 2 days of tremor activity than at other times, adding to evidence of a connection between tremor and earthquakes. (Geochemistry, Geophysics, Geosystems, doi:10.1029/2011GC003559, 2011)

  4. ALMA measures Calama earthquake (United States)

    Brito, R.; Shillue, B.


    On 4 March 2010, the ALMA system response to an extraordinarily large disturbance was measured when a magnitude 6.3 earthquake struck near Calama, Chile, relatively close to the ALMA site. Figures 1 through 4 demonstrate the remarkable performance of the ALMA system to a huge disturbance that was more than 100 times the specification for correction accuracy.

  5. Road Damage Following Earthquake (United States)


    Ground shaking triggered liquefaction in a subsurface layer of water-saturated sand, producing differential lateral and vertical movement in a overlying carapace of unliquified sand and slit, which moved from right to left towards the Pajaro River. This mode of ground failure, termed lateral spreading, is a principal cause of liquefaction-related earthquake damage caused by the Oct. 17, 1989, Loma Prieta earthquake. Sand and soil grains have faces that can cause friction as they roll and slide against each other, or even cause sticking and form small voids between grains. This complex behavior can cause soil to behave like a liquid under certain conditions such as earthquakes or when powders are handled in industrial processes. Mechanics of Granular Materials (MGM) experiments aboard the Space Shuttle use the microgravity of space to simulate this behavior under conditons that carnot be achieved in laboratory tests on Earth. MGM is shedding light on the behavior of fine-grain materials under low effective stresses. Applications include earthquake engineering, granular flow technologies (such as powder feed systems for pharmaceuticals and fertilizers), and terrestrial and planetary geology. Nine MGM specimens have flown on two Space Shuttle flights. Another three are scheduled to fly on STS-107. The principal investigator is Stein Sture of the University of Colorado at Boulder. Credit: S.D. Ellen, U.S. Geological Survey

  6. Dynamic Source Inversion of Intermediate Depth Earthquakes in Mexico (United States)

    Yuto Sho Mirwald, Aron; Cruz-Atienza, Victor Manuel; Krishna Singh-Singh, Shri


    The source mechanisms of earthquakes at intermediate depth (50-300 km) are still under debate. Due to the high confining pressure at depths below 50 km, rocks ought to deform by ductile flow rather than brittle failure, which is the mechanism originating most earthquakes. Several source mechanisms have been proposed, but for neither of them conclusive evidence has been found. One of two viable mechanisms is Dehydration Embrittlement, where liberation of water lowers the effective pressure and enables brittle fracture. The other is Thermal Runaway, a highly localized ductile deformation (Prieto et. al., Tecto., 2012). In the Mexican subduction zone, intermediate depth earthquakes represent a real hazard in central Mexico due to their proximity to highly populated areas and the large accelerations induced on ground motion (Iglesias et. al., BSSA, 2002). To improve our understanding of these rupture processes, we use a recently introduced inversion method (Diaz-Mojica et. al., JGR, 2014) to analyze several intermediate depth earthquakes in Mexico. The method inverts strong motion seismograms to determine the dynamic source parameters based on a genetic algorithm. It has been successfully used for the M6.5 Zumpango earthquake that occurred at a depth of 62 km in the state of Guerrero, Mexico. For this event, high radiated energy, low radiation efficiency and low rupture velocity were determined. This indicates a highly dissipative rupture process, suggesting that Thermal Runaway could probably be the dominant source process. In this work we improved the inversion method by introducing a theoretical consideration for the nucleation process that minimizes the effects of rupture initiation and guarantees self-sustained rupture propagation (Galis et. al., GJInt., 2014). Preliminary results indicate that intermediate depth earthquakes in central Mexico may vary in their rupture process. For instance, for a M5.9 normal-faulting earthquake at 55 km depth that produced very

  7. The HayWired earthquake scenario—Earthquake hazards (United States)

    Detweiler, Shane T.; Wein, Anne M.


    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

  8. Hazus® estimated annualized earthquake losses for the United States (United States)

    Jaiswal, Kishor; Bausch, Doug; Rozelle, Jesse; Holub, John; McGowan, Sean


    Large earthquakes can cause social and economic disruption that can be unprecedented to any given community, and the full recovery from these impacts may or may not always be achievable. In the United States (U.S.), the 1994 M6.7 Northridge earthquake in California remains the third costliest disaster in U.S. history; and it was one of the most expensive disasters for the federal government. Internationally, earthquakes in the last decade alone have claimed tens of thousands of lives and caused hundreds of billions of dollars of economic impact throughout the globe (~90 billion U.S. dollars (USD) from 2008 M7.9 Wenchuan China, ~20 billion USD from 2010 M8.8 Maule earthquake in Chile, ~220 billion USD from 2011 M9.0 Tohoku Japan earthquake, ~25 billion USD from 2011 M6.3 Christchurch New Zealand, and ~22 billion USD from 2016 M7.0 Kumamoto Japan). Recent earthquakes show a pattern of steadily increasing damages and losses that are primarily due to three key factors: (1) significant growth in earthquake-prone urban areas, (2) vulnerability of the older building stock, including poorly engineered non-ductile concrete buildings, and (3) an increased interdependency in terms of supply and demand for the businesses that operate among different parts of the world. In the United States, earthquake risk continues to grow with increased exposure of population and development even though the earthquake hazard has remained relatively stable except for the regions of induced seismic activity. Understanding the seismic hazard requires studying earthquake characteristics and locales in which they occur, while understanding the risk requires an assessment of the potential damage from earthquake shaking to the built environment and to the welfare of people—especially in high-risk areas. Estimating the varying degree of earthquake risk throughout the United States is critical for informed decision-making on mitigation policies, priorities, strategies, and funding levels in the

  9. a Collaborative Cyberinfrastructure for Earthquake Seismology (United States)

    Bossu, R.; Roussel, F.; Mazet-Roux, G.; Lefebvre, S.; Steed, R.


    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 (, 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

  10. Fault-based Earthquake Rupture Forecasts for Western Gulf of Corinth, Greece (United States)

    Ganas, A.; Parsons, T.; Segkou, M.


    The western Gulf of Corinth has not experienced a strong earthquake since 1995 (the Ms=6.2 event of Aigion on 15 June 1995; Bernard et al., 1997), although the Gulf is extending fast (over 12 mm/yr of N-S extension from continuous GPS data spanning a period of 9+ years) and its seismic history since 1769 exhibits twelve (12) shallow events with M>6.0. We undertook an analysis of rupture forecasts along the active faults in this area of central Greece, using most updated datasets (active fault maps, fault geometry, fault slip rates, trenching data on past earthquakes, historical and instrumental seismicity, strain) and models for earthquake budget extrapolated from observed seismicity, magnitude-frequency distributions and calculated earthquake rates vs. magnitude for individual faults. We present a unified rupture forecast model that comprises a time-independent (Poisson-process) earthquake rate model, and a time-dependent earthquake-probability model, based on recent earthquake rates and stress-renewal statistics conditioned on the date of last event. The resulting rupture rate maps may be used to update building codes and promote mitigation efforts.

  11. San Andreas Fault, California, M 5.5 or greater Earthquakes 1800-2000 (United States)

    Toppozada, T.; Branum, D.; Reichle, M.; Hallstrom, C.


    The San Andreas fault has been the most significant source of major California earthquakes since 1800. From 1812 to 1906 it generated four major earthquakes of M 7.2 or greater in two pairs on two major regions of the fault. A pair of major earthquakes occurred on the Central to Southern region, where the 1857 faulting overlapped the 1812 earthquake faulting. And a pair of major earthquakes occurred on the Northern region, where the 1906 faulting overlapped the 1838 earthquake faulting. The 1812 earthquake resulted from a rupture of up to about 200 km, from the region of Cajon Pass to as far as about 50 km west of Fort Tejon (Sieh and others, 1989). This rupture is the probable source of both the destructive 1812.12.8 "San Juan Capistrano" and the 1812.12.21 "Santa Barbara Channel" earthquakes. The 1838 earthquake's damage effects throughout the Bay area, from San Francisco to Santa Clara Valley and Monterey, were unequalled by any Bay area earthquake other than the 1906 event. The mainshock's effects, and numerous strong probable aftershocks in the San Juan Bautista vicinity in the following three years, suggest 1838 faulting from San Francisco to San Juan Bautista, and M about 7.4. The 630 km length of the San Andreas fault between San Francisco and Cajon Pass ruptured in the 1838 and 1857 earthquakes, except for about 75 km between Bitterwater and San Juan Bautista. The 1840-1841 probable aftershocks of the 1838 event occurred near San Juan Bautista, and the foreshocks and aftershocks of the 1857 event occurred near Bitterwater. In the Bitterwater area, strong earthquakes continued to occur until the 1885 earthquake of M 6.5. Near Parkfield, 40 to 70 km southeast of Bitterwater, M 5.5 or greater earthquakes have occurred from the 1870s to the 1960s. In the total Bitterwater to Parkfield zone bracketing the northern end of the 1857 rupture, the seismicity and moment release has decreased steadily since 1857, and has tended to migrate southeastward with time. The

  12. Except in Highly Idealized Cases, Repeating Earthquakes and Laboratory Earthquakes are Neither Time- nor Slip-Predictable (United States)

    Rubinstein, J. L.; Ellsworth, W. L.; Beeler, N. M.; Chen, K. H.; Lockner, D. A.; Uchida, N.


    Sequences of repeating earthquakes in California, Taiwan and Japan are characterized by interevent times that are more regular than expected from a Poisson process, and are better described by a 2-parameter renewal model (mean rate and variability) of independent and identically distributed intervals that only depends on the time of the last event. Using precise measurements of the relative size of earthquakes in each repeating earthquake family we examine the additional predictive power of the time- and slip-predictable models. We find that neither model offers statistically significant predictive power over a renewal model. In a highly idealized laboratory system, we find that earthquakes are both time- and slip-predictable, but with the addition of a small amount of the complexity (e.g., an uneven fault surface) the time- and slip-predictable models offer little or no advantage over a much simpler renewal model that has constant slip or constant recurrence intervals. Given that repeating natural and laboratory earthquakes are not well explained by either time- or slip-predictability, we conclude that these models are too idealized to explain the recurrence behavior of natural earthquakes. These models likely fail because their key assumptions (1 -- constant loading rate, 2 -- constant failure threshold OR constant final stress, and 3 - the fault is locked throughout the loading cycle) are too idealized to apply in a complex, natural system. While the time- and slip-predictable models do not appear to work for natural earthquakes, we do note that moment (slip) scales with recurrence time according to the mean magnitude of each repeating earthquake family in Parkfield, CA, but not in the other locations. While earthquake size and recurrence time are related in Parkfield, the simplest slip-predictable model still doesn’t work because fitting a linear trend to the data predicts a non-zero earthquake size at instantaneous recurrence time. This scaling, its presence

  13. Increase in Ozone hole and hence UV-B Preceding Earthquakes (United States)

    Mukherjee, A.; Mukherjee, S.


    Before the occurrence of earthquake, the change has been observed in ozone hole as well as UV-B flux in the atmosphere of the earth. After earthquake the UV-B flux reduces, which is correlated with the fluctuation in atmospheric temperature as well as Electron flux in Sun-Earth environment. Actual measurement show a linear relationship in between Coronal Mass Ejection and increase in Solar UV- B before the earthquakes in various parts of India.

  14. Lithospheric flexure under the Hawaiian volcanic load: Internal stresses and a broken plate revealed by earthquakes (United States)

    Klein, Fred W.


    Several lines of earthquake evidence indicate that the lithospheric plate is broken under the load of the island of Hawai`i, where the geometry of the lithosphere is circular with a central depression. The plate bends concave downward surrounding a stress-free hole, rather than bending concave upward as with past assumptions. Earthquake focal mechanisms show that the center of load stress and the weak hole is between the summits of Mauna Loa and Mauna Kea where the load is greatest. The earthquake gap at 21 km depth coincides with the predicted neutral plane of flexure where horizontal stress changes sign. Focal mechanism P axes below the neutral plane display a striking radial pattern pointing to the stress center. Earthquakes above the neutral plane in the north part of the island have opposite stress patterns; T axes tend to be radial. The M6.2 Honomu and M6.7 Kiholo main shocks (both at 39 km depth) are below the neutral plane and show radial compression, and the M6.0 Kiholo aftershock above the neutral plane has tangential compression. Earthquakes deeper than 20 km define a donut of seismicity around the stress center where flexural bending is a maximum. The hole is interpreted as the soft center where the lithospheric plate is broken. Kilauea's deep conduit is seismically active because it is in the ring of maximum bending. A simplified two-dimensional stress model for a bending slab with a load at one end yields stress orientations that agree with earthquake stress axes and radial P axes below the neutral plane. A previous inversion of deep Hawaiian focal mechanisms found a circular solution around the stress center that agrees with the model. For horizontal faults, the shear stress within the bending slab matches the slip in the deep Kilauea seismic zone and enhances outward slip of active flanks.

  15. Geomorphic legacy of medieval Himalayan earthquakes in the Pokhara Valley (United States)

    Schwanghart, Wolfgang; Bernhardt, Anne; Stolle, Amelie; Hoelzmann, Philipp; Adhikari, Basanta R.; Andermann, Christoff; Tofelde, Stefanie; Merchel, Silke; Rugel, Georg; Fort, Monique; Korup, Oliver


    The Himalayas and their foreland belong to the world's most earthquake-prone regions. With millions of people at risk from severe ground shaking and associated damages, reliable data on the spatial and temporal occurrence of past major earthquakes is urgently needed to inform seismic risk analysis. Beyond the instrumental record such information has been largely based on historical accounts and trench studies. Written records provide evidence for damages and fatalities, yet are difficult to interpret when derived from the far-field. Trench studies, in turn, offer information on rupture histories, lengths and displacements along faults but involve high chronological uncertainties and fail to record earthquakes that do not rupture the surface. Thus, additional and independent information is required for developing reliable earthquake histories. Here, we present exceptionally well-dated evidence of catastrophic valley infill in the Pokhara Valley, Nepal. Bayesian calibration of radiocarbon dates from peat beds, plant macrofossils, and humic silts in fine-grained tributary sediments yields a robust age distribution that matches the timing of nearby M>8 earthquakes in ~1100, 1255, and 1344 AD. The upstream dip of tributary valley fills and X-ray fluorescence spectrometry of their provenance rule out local sediment sources. Instead, geomorphic and sedimentary evidence is consistent with catastrophic fluvial aggradation and debris flows that had plugged several tributaries with tens of meters of calcareous sediment from the Annapurna Massif >60 km away. The landscape-changing consequences of past large Himalayan earthquakes have so far been elusive. Catastrophic aggradation in the wake of two historically documented medieval earthquakes and one inferred from trench studies underscores that Himalayan valley fills should be considered as potential archives of past earthquakes. Such valley fills are pervasive in the Lesser Himalaya though high erosion rates reduce

  16. Analysis of rupture area of aftershocks caused by twin earthquakes (Case study: 11 April 2012 earthquakes of Aceh-North Sumatra)

    Energy Technology Data Exchange (ETDEWEB)

    Diansari, Angga Vertika, E-mail:; Purwana, Ibnu; Subakti, Hendri [Academy of Meteorology and Geophysics, Jalan Perhubungan I no.5 Tangerang 15221 (Indonesia)


    The 11 April 2012 earthquakes off-shore Aceh-North Sumatra are unique events for the history of Indonesian earthquake. It is unique because that they have similar magnitude, 8.5 Mw and 8.1 Mw; close to epicenter distance, similar strike-slip focal mechanism, and occuring in outer rise area. The purposes of this research are: (1) comparing area of earthquakes base on models and that of calculation, (2) fitting the shape and the area of earthquake rupture zones, (3) analyzing the relationship between rupture area and magnitude of the earthquakes. Rupture area of the earthquake fault are determined by using 4 different formulas, i.e. Utsu and Seki (1954), Wells and Coppersmith (1994), Ellsworth (2003), and Christophersen and Smith (2000). The earthquakes aftershock parameters are taken from PGN (PusatGempabumiNasional or National Earthquake Information Center) of BMKG (Indonesia Agency Meteorology Climatology and Geophysics). The aftershock epicenters are plotted by GMT’s software. After that, ellipse and rectangular models of aftershock spreading are made. The results show that: (1) rupture areas were calculated using magnitude relationship which are larger than the the aftershock distributions model, (2) the best fitting model for that earthquake aftershock distribution is rectangular associated with Utsu and Seki (1954) formula, (3) the larger the magnitude of the earthquake, the larger area of the fault.

  17. Modern earthquake engineering offshore and land-based structures

    CERN Document Server

    Jia, Junbo


    This book addresses applications of earthquake engineering for both offshore and land-based structures. It is self-contained as a reference work and covers a wide range of topics, including topics related to engineering seismology, geotechnical earthquake engineering, structural engineering, as well as special contents dedicated to design philosophy, determination of ground motions, shock waves, tsunamis, earthquake damage, seismic response of offshore and arctic structures, spatial varied ground motions, simplified and advanced seismic analysis methods, sudden subsidence of offshore platforms, tank liquid impacts during earthquakes, seismic resistance of non-structural elements, and various types of mitigation measures, etc. The target readership includes professionals in offshore and civil engineering, officials and regulators, as well as researchers and students in this field.

  18. Geoengineering and seismological aspects of the Niigata-Ken Chuetsu-Oki earthquake of 16 July 2007 (United States)

    Kayen, R.; Brandenberg, S.J.; CoIlins, B.D.; Dickenson, S.; Ashford, S.; Kawamata, Y.; Tanaka, Y.; Koumoto, H.; Abrahamson, N.; Cluff, L.; Tokimatsu, K.


    The M6.6 Niigata-Ken Chuetsu-Oki earthquake of 16 July 2007 occurred off the west coast of Japan with a focal depth of 10 km, immediately west of Kashiwazaki City and Kariwa Village in southern Niigata Prefecture. Peak horizontal ground accelerations of 0.68 g were measured in Kashiwazaki City, as well as at the reactor floor level of the world's largest nuclear reactor, located on the coast at Kariwa Village. Liquefaction of historic and modern river deposits, aeolian dune sand, and manmade fill was widespread in the coastal region nearest the epicenter and caused ground deformations that damaged bridges, embankments, roadways, buildings, ports, railways and utilities. Landslides along the coast of southern Niigata Prefecture and in mountainous regions inland of Kashiwazaki were also widespread affecting transportation infrastructure. Liquefaction and a landslide also damaged the nuclear power plant sites. This paper, along with a companion digital map database available at http://walrus.wr.usgs.gOv/infobank/n/nii07jp/html/n-ii-07-jp.sites.kmz, describes the seismological and geo-engineering aspects of the event. ?? 2009, Earthquake Engineering Research Institute.

  19. Quantification of social contributions to earthquake mortality (United States)

    Main, I. G.; NicBhloscaidh, M.; McCloskey, J.; Pelling, M.; Naylor, M.


    Death tolls in earthquakes, which continue to grow rapidly, are the result of complex interactions between physical effects, such as strong shaking, and the resilience of exposed populations and supporting critical infrastructures and institutions. While it is clear that the social context in which the earthquake occurs has a strong effect on the outcome, the influence of this context can only be exposed if we first decouple, as much as we can, the physical causes of mortality from our consideration. (Our modelling assumes that building resilience to shaking is a social factor governed by national wealth, legislation and enforcement and governance leading to reduced levels of corruption.) Here we attempt to remove these causes by statistically modelling published mortality, shaking intensity and population exposure data; unexplained variance from this physical model illuminates the contribution of socio-economic factors to increasing earthquake mortality. We find that this variance partitions countries in terms of basic socio-economic measures and allows the definition of a national vulnerability index identifying both anomalously resilient and anomalously vulnerable countries. In many cases resilience is well correlated with GDP; people in the richest countries are unsurprisingly safe from even the worst shaking. However some low-GDP countries rival even the richest in resilience, showing that relatively low cost interventions can have a positive impact on earthquake resilience and that social learning between these countries might facilitate resilience building in the absence of expensive engineering interventions.

  20. Detailed source process of the 2007 Tocopilla earthquake. (United States)

    Peyrat, S.; Madariaga, R.; Campos, J.; Asch, G.; Favreau, P.; Bernard, P.; Vilotte, J.


    We investigated the detail rupture process of the Tocopilla earthquake (Mw 7.7) of the 14 November 2007 and of the main aftershocks that occurred in the southern part of the North Chile seismic gap using strong motion data. The earthquake happen in the middle of the permanent broad band and strong motion network IPOC newly installed by GFZ and IPGP, and of a digital strong-motion network operated by the University of Chile. The Tocopilla earthquake is the last large thrust subduction earthquake that occurred since the major Iquique 1877 earthquake which produced a destructive tsunami. The Arequipa (2001) and Antofagasta (1995) earthquakes already ruptured the northern and southern parts of the gap, and the intraplate intermediate depth Tarapaca earthquake (2005) may have changed the tectonic loading of this part of the Peru-Chile subduction zone. For large earthquakes, the depth of the seismic rupture is bounded by the depth of the seismogenic zone. What controls the horizontal extent of the rupture for large earthquakes is less clear. Factors that influence the extent of the rupture include fault geometry, variations of material properties and stress heterogeneities inherited from the previous ruptures history. For subduction zones where structures are not well known, what may have stopped the rupture is not obvious. One crucial problem raised by the Tocopilla earthquake is to understand why this earthquake didn't extent further north, and at south, what is the role of the Mejillones peninsula that seems to act as a barrier. The focal mechanism was determined using teleseismic waveforms inversion and with a geodetic analysis (cf. Campos et al.; Bejarpi et al., in the same session). We studied the detailed source process using the strong motion data available. This earthquake ruptured the interplate seismic zone over more than 150 km and generated several large aftershocks, mainly located south of the rupture area. The strong-motion data show clearly two S

  1. The Global Earthquake Model - Past, Present, Future (United States)

    Smolka, Anselm; Schneider, John; Stein, Ross


    The Global Earthquake Model (GEM) is a unique collaborative effort that aims to provide organizations and individuals with tools and resources for transparent assessment of earthquake risk anywhere in the world. By pooling data, knowledge and people, GEM acts as an international forum for collaboration and exchange. Sharing of data and risk information, best practices, and approaches across the globe are key to assessing risk more effectively. Through consortium driven global projects, open-source IT development and collaborations with more than 10 regions, leading experts are developing unique global datasets, best practice, open tools and models for seismic hazard and risk assessment. The year 2013 has seen the completion of ten global data sets or components addressing various aspects of earthquake hazard and risk, as well as two GEM-related, but independently managed regional projects SHARE and EMME. Notably, the International Seismological Centre (ISC) led the development of a new ISC-GEM global instrumental earthquake catalogue, which was made publicly available in early 2013. It has set a new standard for global earthquake catalogues and has found widespread acceptance and application in the global earthquake community. By the end of 2014, GEM's OpenQuake computational platform will provide the OpenQuake hazard/risk assessment software and integrate all GEM data and information products. The public release of OpenQuake is planned for the end of this 2014, and will comprise the following datasets and models: • ISC-GEM Instrumental Earthquake Catalogue (released January 2013) • Global Earthquake History Catalogue [1000-1903] • Global Geodetic Strain Rate Database and Model • Global Active Fault Database • Tectonic Regionalisation Model • Global Exposure Database • Buildings and Population Database • Earthquake Consequences Database • Physical Vulnerabilities Database • Socio-Economic Vulnerability and Resilience Indicators • Seismic

  2. Long-term predictability of regions and dates of strong earthquakes (United States)

    Kubyshen, Alexander; Doda, Leonid; Shopin, Sergey


    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

  3. Investigation of the Three-Dimensional Hinge Moment Characteristics Generated by the ONERA-M6 Wing with an Aileron

    Directory of Open Access Journals (Sweden)

    G. Q. Zhang


    Full Text Available The hinge moment characteristics for ONERA-M6 wing with aileron configuration have been investigated numerically based on the different gaps and deflecting angles. The results show that the effects on the wing made by the deflecting aileron are notable. Comparing with the nonaileron case, the chordwise pressure coefficient distribution for the wing with aileron has shown the totally different trends. The small gap can force the air flow through and form the extremely strong spraying flow. It can directly destroy the previously formed leading edge vortex (LEV. Due to the presence of the positive deflecting angle, the trailing edge vortex (TEV will begin to generate at the trailing edge of the aileron. The induced secondary LEV will be mixed with the developing TEVs and form the stronger TEVs at the downstream position. Comparing with the subsonic flow, the curve for the supersonic flow has shown a good linear. The corresponding hinge moments are also extremely sensitive to the changing angle of attack, and the slope of curves is also bigger than that of the subsonic flow. The bigger gap and deflecting angle can result in the curve of hinge moment bending upward at high angle of attack. The corresponding pressure cloud and streamlines have also been obtained computationally and analyzed in detail.

  4. Sequence of deep-focus earthquakes beneath the Bonin Islands identified by the NIED nationwide dense seismic networks Hi-net and F-net (United States)

    Takemura, Shunsuke; Saito, Tatsuhiko; Shiomi, Katsuhiko


    An M 6.8 ( Mw 6.5) deep-focus earthquake occurred beneath the Bonin Islands at 21:18 (JST) on June 23, 2015. Observed high-frequency (>1 Hz) seismograms across Japan, which contain several sets of P- and S-wave arrivals for the 10 min after the origin time, indicate that moderate-to-large earthquakes occurred sequentially around Japan. Snapshots of the seismic energy propagation illustrate that after one deep-focus earthquake occurred beneath the Sea of Japan, two deep-focus earthquakes occurred sequentially after the first ( Mw 6.5) event beneath the Bonin Islands in the next 4 min. The United States Geological Survey catalog includes three Bonin deep-focus earthquakes with similar hypocenter locations, but their estimated magnitudes are inconsistent with seismograms from across Japan. The maximum-amplitude patterns of the latter two earthquakes were similar to that of the first Bonin earthquake, which indicates similar locations and mechanisms. Furthermore, based on the ratios of the S-wave amplitudes to that of the first event, the magnitudes of the latter events are estimated as M 6.5 ± 0.02 and M 5.8 ± 0.02, respectively. Three magnitude-6-class earthquakes occurred sequentially within 4 min in the Pacific slab at 480 km depth, where complex heterogeneities exist within the slab.[Figure not available: see fulltext.

  5. Solar activity and earthquake

    Energy Technology Data Exchange (ETDEWEB)

    Yuan, J.


    Prolonged astronomical observations have discovered that the Sun, which is the nearest star to the Earth, is not calm and serene. On the solar surface, there are often windstorms, electrical lights, and sometimes large flame eruptions; and there are regularly black spots in patches which are also active. The Sun not only disperses light and heat, but also throws out large quantities of currents of charged particles to be scattered in space and to reach the Earth, sometimes, which are called by some solar winds. These activities in the Sun can induce many physical phenomena on earth, including magnetic storms, polar light, sudden disruption or attenuation of medium- and short-wave radio, and many atmospheric changes. Some scientists believe they are perhaps also related to the occurrence of earthquakes. This paper explains these solar activities and their possible relationship to earthquakes.

  6. Uncertainty Analysis of Static Coulomb Stress Change Induced by Earthquake A Case Study on the 2008 Ms 8.0 Wenchuan Earthquake

    Institute of Scientific and Technical Information of China (English)

    Wang Liwei; Chen Qifu


    Static Coulomb stress change induced by earthquake slip is frequently used to explain earthquake activities and aftershock distribution. However, some parameters for the Coulomb stress calculation are unable to be well constrained from laboratory experiments and field observations. Different parameters may directly affect the pattern of static Coulomb stress. The static Coulomb stress changes induced by the Wenchuan earthquake calculated by six research groups are not consistent with each other. To investigate how the parameters affect the calculation results, we change the parameters in turn through modeling and compare the results of different calculation parameters. We find that gravity, position and strike of receiver faults have little influence on coseismic Coulomb stress calculations, but other parameters can change the value and sign of the results in various degrees especially around the earthquake rupture plane. Therefore the uncertainty analysis of static Coulomb stress change induced by earthquake should be taken into consideration in the earthquake hazard analysis.

  7. Do Earthquakes Shake Stock Markets? (United States)

    Ferreira, Susana; Karali, Berna


    This paper examines how major earthquakes affected the returns and volatility of aggregate stock market indices in thirty-five financial markets over the last twenty years. Results show that global financial markets are resilient to shocks caused by earthquakes even if these are domestic. Our analysis reveals that, in a few instances, some macroeconomic variables and earthquake characteristics (gross domestic product per capita, trade openness, bilateral trade flows, earthquake magnitude, a tsunami indicator, distance to the epicenter, and number of fatalities) mediate the impact of earthquakes on stock market returns, resulting in a zero net effect. However, the influence of these variables is market-specific, indicating no systematic pattern across global capital markets. Results also demonstrate that stock market volatility is unaffected by earthquakes, except for Japan.

  8. Pain after earthquake

    Directory of Open Access Journals (Sweden)

    Angeletti Chiara


    Full Text Available Abstract Introduction On 6 April 2009, at 03:32 local time, an Mw 6.3 earthquake hit the Abruzzi region of central Italy causing widespread damage in the City of L Aquila and its nearby villages. The earthquake caused 308 casualties and over 1,500 injuries, displaced more than 25,000 people and induced significant damage to more than 10,000 buildings in the L'Aquila region. Objectives This observational retrospective study evaluated the prevalence and drug treatment of pain in the five weeks following the L'Aquila earthquake (April 6, 2009. Methods 958 triage documents were analysed for patients pain severity, pain type, and treatment efficacy. Results A third of pain patients reported pain with a prevalence of 34.6%. More than half of pain patients reported severe pain (58.8%. Analgesic agents were limited to available drugs: anti-inflammatory agents, paracetamol, and weak opioids. Reduction in verbal numerical pain scores within the first 24 hours after treatment was achieved with the medications at hand. Pain prevalence and characterization exhibited a biphasic pattern with acute pain syndromes owing to trauma occurring in the first 15 days after the earthquake; traumatic pain then decreased and re-surged at around week five, owing to rebuilding efforts. In the second through fourth week, reports of pain occurred mainly owing to relapses of chronic conditions. Conclusions This study indicates that pain is prevalent during natural disasters, may exhibit a discernible pattern over the weeks following the event, and current drug treatments in this region may be adequate for emergency situations.

  9. The ethics of earthquake prediction. (United States)

    Sol, Ayhan; Turan, Halil


    Scientists' responsibility to inform the public about their results may conflict with their responsibility not to cause social disturbance by the communication of these results. A study of the well-known Brady-Spence and Iben Browning earthquake predictions illustrates this conflict in the publication of scientifically unwarranted predictions. Furthermore, a public policy that considers public sensitivity caused by such publications as an opportunity to promote public awareness is ethically problematic from (i) a refined consequentialist point of view that any means cannot be justified by any ends, and (ii) a rights view according to which individuals should never be treated as a mere means to ends. The Parkfield experiment, the so-called paradigm case of cooperation between natural and social scientists and the political authorities in hazard management and risk communication, is also open to similar ethical criticism. For the people in the Parkfield area were not informed that the whole experiment was based on a contested seismological paradigm.

  10. New characteristics of intensity assessment of Sichuan Lushan "4.20" M s7.0 earthquake (United States)

    Sun, Baitao; Yan, Peilei; Chen, Xiangzhao


    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.

  11. Large earthquakes create vertical permeability by breaching aquitards (United States)

    Wang, Chi-Yuen; Liao, Xin; Wang, Lee-Ping; Wang, Chung-Ho; Manga, Michael


    Hydrologic responses to earthquakes and their mechanisms have been widely studied. Some responses have been attributed to increases in the vertical permeability. However, basic questions remain: How do increases in the vertical permeability occur? How frequently do they occur? Is there a quantitative measure for detecting the occurrence of aquitard breaching? We try to answer these questions by examining data from a dense network of ˜50 monitoring stations of clustered wells in a sedimentary basin near the epicenter of the 1999 M7.6 Chi-Chi earthquake in western Taiwan. While most stations show evidence that confined aquifers remained confined after the earthquake, about 10% of the stations show evidence of coseismic breaching of aquitards, creating vertical permeability as high as that of aquifers. The water levels in wells without evidence of coseismic breaching of aquitards show tidal responses similar to that of a confined aquifer before and after the earthquake. Those wells with evidence of coseismic breaching of aquitards, on the other hand, show distinctly different postseismic tidal response. Furthermore, the postseismic tidal response of different aquifers became strikingly similar, suggesting that the aquifers became hydraulically connected and the connection was maintained many months thereafter. Breaching of aquitards by large earthquakes has significant implications for a number of societal issues such as the safety of water resources, the security of underground waste repositories, and the production of oil and gas. The method demonstrated here may be used for detecting the occurrence of aquitard breaching by large earthquakes in other seismically active areas.

  12. LIDAR Helps Identify Source of 1872 Earthquake Near Chelan, Washington (United States)

    Sherrod, B. L.; Blakely, R. J.; Weaver, C. S.


    One of the largest historic earthquakes in the Pacific Northwest occurred on 15 December 1872 (M6.5-7) near the south end of Lake Chelan in north-central Washington State. Lack of recognized surface deformation suggested that the earthquake occurred on a blind, perhaps deep, fault. New LiDAR data show landslides and a ~6 km long, NW-side-up scarp in Spencer Canyon, ~30 km south of Lake Chelan. Two landslides in Spencer Canyon impounded small ponds. An historical account indicated that dead trees were visible in one pond in AD1884. Wood from a snag in the pond yielded a calibrated age of AD1670-1940. Tree ring counts show that the oldest living trees on each landslide are 130 and 128 years old. The larger of the two landslides obliterated the scarp and thus, post-dates the last scarp-forming event. Two trenches across the scarp exposed a NW-dipping thrust fault. One trench exposed alluvial fan deposits, Mazama ash, and scarp colluvium cut by a single thrust fault. Three charcoal samples from a colluvium buried during the last fault displacement had calibrated ages between AD1680 and AD1940. The second trench exposed gneiss thrust over colluvium during at least two, and possibly three fault displacements. The younger of two charcoal samples collected from a colluvium below gneiss had a calibrated age of AD1665- AD1905. For an historical constraint, we assume that the lack of felt reports for large earthquakes in the period between 1872 and today indicates that no large earthquakes capable of rupturing the ground surface occurred in the region after the 1872 earthquake; thus the last displacement on the Spencer Canyon scarp cannot post-date the 1872 earthquake. Modeling of the age data suggests that the last displacement occurred between AD1840 and AD1890. These data, combined with the historical record, indicate that this fault is the source of the 1872 earthquake. Analyses of aeromagnetic data reveal lithologic contacts beneath the scarp that form an ENE

  13. Foreshocks of strong earthquakes (United States)

    Guglielmi, A. V.; Sobisevich, L. E.; Sobisevich, A. L.; Lavrov, I. P.


    The specific enhancement of ultra-low-frequency (ULF) electromagnetic oscillations a few hours prior to the strong earthquakes, which was previously mentioned in the literature, motivated us to search for the distinctive features of the mechanical (foreshock) activity of the Earth's crust in the epicentral zones of the future earthquakes. Activation of the foreshocks three hours before the main shock is revealed, which is roughly similar to the enhancement of the specific electromagnetic ULF emission. It is hypothesized that the round-the-world seismic echo signals from the earthquakes, which form the peak of energy release 2 h 50 min before the main events, act as the triggers of the main shocks due to the cumulative action of the surface waves converging to the epicenter. It is established that the frequency of the fluctuations in the foreshock activity decreases at the final stages of the preparation of the main shocks, which probably testifies to the so-called mode softening at the approach of the failure point according to the catastrophe theory.

  14. Hotspots, Lifelines, and the Safrr Haywired Earthquake Sequence (United States)

    Ratliff, J. L.; Porter, K.


    Though California has experienced many large earthquakes (San Francisco, 1906; Loma Prieta, 1989; Northridge, 1994), the San Francisco Bay Area has not had a damaging earthquake for 25 years. Earthquake risk and surging reliance on smartphones and the Internet to handle everyday tasks raise the question: is an increasingly technology-reliant Bay Area prepared for potential infrastructure impacts caused by a major earthquake? How will a major earthquake on the Hayward Fault affect lifelines (roads, power, water, communication, etc.)? The U.S. Geological Survey Science Application for Risk Reduction (SAFRR) program's Haywired disaster scenario, a hypothetical two-year earthquake sequence triggered by a M7.05 mainshock on the Hayward Fault, addresses these and other questions. We explore four geographic aspects of lifeline damage from earthquakes: (1) geographic lifeline concentrations, (2) areas where lifelines pass through high shaking or potential ground-failure zones, (3) areas with diminished lifeline service demand due to severe building damage, and (4) areas with increased lifeline service demand due to displaced residents and businesses. Potential mainshock lifeline vulnerability and spatial demand changes will be discerned by superimposing earthquake shaking, liquefaction probability, and landslide probability damage thresholds with lifeline concentrations and with large-capacity shelters. Intersecting high hazard levels and lifeline clusters represent potential lifeline susceptibility hotspots. We will also analyze possible temporal vulnerability and demand changes using an aftershock shaking threshold. The results of this analysis will inform regional lifeline resilience initiatives and response and recovery planning, as well as reveal potential redundancies and weaknesses for Bay Area lifelines. Identified spatial and temporal hotspots can provide stakeholders with a reference for possible systemic vulnerability resulting from an earthquake sequence.

  15. Measures for groundwater security during and after the Hanshin-Awaji earthquake (1995) and the Great East Japan earthquake (2011), Japan (United States)

    Tanaka, Tadashi


    Many big earthquakes have occurred in the tectonic regions of the world, especially in Japan. Earthquakes often cause damage to crucial life services such as water, gas and electricity supply systems and even the sewage system in urban and rural areas. The most severe problem for people affected by earthquakes is access to water for their drinking/cooking and toilet flushing. Securing safe water for daily life in an earthquake emergency requires the establishment of countermeasures, especially in a mega city like Tokyo. This paper described some examples of groundwater use in earthquake emergencies, with reference to reports, books and newspapers published in Japan. The consensus is that groundwater, as a source of water, plays a major role in earthquake emergencies, especially where the accessibility of wells coincides with the emergency need. It is also important to introduce a registration system for citizen-owned and company wells that can form the basis of a cooperative during a disaster; such a registration system was implemented by many Japanese local governments after the Hanshin-Awaji Earthquake in 1995 and the Great East Japan Earthquake in 2011, and is one of the most effective countermeasures for groundwater use in an earthquake emergency. Emphasis is also placed the importance of establishing of a continuous monitoring system of groundwater conditions for both quantity and quality during non-emergency periods.

  16. Structure of the Koyna-Warna Seismic Zone, Maharashtra, India: A possible model for large induced earthquakes elsewhere (United States)

    Catchings, Rufus D.; Dixit, M.M.; Goldman, Mark R.; Kumar, S.


    The Koyna-Warna area of India is one of the best worldwide examples of reservoir-induced seismicity, with the distinction of having generated the largest known induced earthquake (M6.3 on 10 December 1967) and persistent moderate-magnitude (>M5) events for nearly 50 years. Yet, the fault structure and tectonic setting that has accommodated the induced seismicity is poorly known, in part because the seismic events occur beneath a thick sequence of basalt layers. On the basis of the alignment of earthquake epicenters over an ~50 year period, lateral variations in focal mechanisms, upper-crustal tomographic velocity images, geophysical data (aeromagnetic, gravity, and magnetotelluric), geomorphic data, and correlation with similar structures elsewhere, we suggest that the Koyna-Warna area lies within a right step between northwest trending, right-lateral faults. The sub-basalt basement may form a local structural depression (pull-apart basin) caused by extension within the step-over zone between the right-lateral faults. Our postulated model accounts for the observed pattern of normal faulting in a region that is dominated by north-south directed compression. The right-lateral faults extend well beyond the immediate Koyna-Warna area, possibly suggesting a more extensive zone of seismic hazards for the central India area. Induced seismic events have been observed many places worldwide, but relatively large-magnitude induced events are less common because critically stressed, preexisting structures are a necessary component. We suggest that releasing bends and fault step-overs like those we postulate for the Koyna-Warna area may serve as an ideal tectonic environment for generating moderate- to large- magnitude induced (reservoir, injection, etc.) earthquakes.

  17. Earthquake forecasting: Statistics and Information

    CERN Document Server

    Gertsik, V; Krichevets, A


    We present an axiomatic approach to earthquake forecasting in terms of multi-component random fields on a lattice. This approach provides a method for constructing point estimates and confidence intervals for conditional probabilities of strong earthquakes under conditions on the levels of precursors. Also, it provides an approach for setting multilevel alarm system and hypothesis testing for binary alarms. We use a method of comparison for different earthquake forecasts in terms of the increase of Shannon information. 'Forecasting' and 'prediction' of earthquakes are equivalent in this approach.

  18. Earthquake forecasting and its verification

    Directory of Open Access Journals (Sweden)

    J. R. Holliday


    Full Text Available No proven method is currently available for the reliable short time prediction of earthquakes (minutes to months. However, it is possible to make probabilistic hazard assessments for earthquake risk. In this paper we discuss a new approach to earthquake forecasting based on a pattern informatics (PI method which quantifies temporal variations in seismicity. The output, which is based on an association of small earthquakes with future large earthquakes, is a map of areas in a seismogenic region ('hotspots'' where earthquakes are forecast to occur in a future 10-year time span. This approach has been successfully applied to California, to Japan, and on a worldwide basis. Because a sharp decision threshold is used, these forecasts are binary--an earthquake is forecast either to occur or to not occur. The standard approach to the evaluation of a binary forecast is the use of the relative (or receiver operating characteristic (ROC diagram, which is a more restrictive test and less subject to bias than maximum likelihood tests. To test our PI method, we made two types of retrospective forecasts for California. The first is the PI method and the second is a relative intensity (RI forecast based on the hypothesis that future large earthquakes will occur where most smaller earthquakes have occurred in the recent past. While both retrospective forecasts are for the ten year period 1 January 2000 to 31 December 2009, we performed an interim analysis 5 years into the forecast. The PI method out performs the RI method under most circumstances.

  19. Groundwater Eruption in China Triggered By the 2004 Sumatra Earthquake (United States)

    Shi, Z.; Wang, D.; Manga, M.; Wang, C. Y.; Wang, G.


    The 2004 Mw9.3 Sumatra earthquake initiated a large, sustained groundwater eruption in Guangdong, China, 3200 km away from the epicenter. The erupted water column reached a height of ~60 m above the ground surface when it was first sighted and the eruption lasted about 10 days. Estimated seismic energy density at the eruption site is only 0.046 J.m-3; thus it is surprising that the earthquake caused such an intense response. A field survey showed that a large amount of gaseous CO2 was released from groundwater during the eruption and suggested that the eruption was caused by the exsolution of CO2 from groundwater. In this study, we use numerical simulation to explore the mechanism of the well eruption. We apply tidal analysis to water level data from 2003 to 2006 to estimate the aquifer parameters before and after the earthquake; the hydraulic diffusivity inferred this way is 0.423 m2/s and 1.371 m2/s before and after the earthquake, respectively. Based on these parameters, we use TOUGH2, a widely used numerical program for simulating two-phase hydrothermal processes, to simulate the evolution of CO2 saturation, the velocity of erupted groundwater and pressure in the well-aquifer system after Sumatra earthquake. The simulations show that the earthquake may have triggered bubbles to nucleate from the CO2-rich groundwater and enhanced the aquifer permeability, leading to increased groundwater discharge to the well. Decreased pore-pressure in the aquifer caused greater exsolution of CO2 and greater discharge, leading to groundwater eruption. Exsolution of CO2 extends radially away from the wellbore as a function of time and the continued exsolution of CO2 sustained the eruption until pressure in the aquifer drops below hydrostatic, which is marked by a ~9 m drop in groundwater level from that before the earthquake. That earthquake trigger eruption and CO2 exsolution has implications for CO2 sequestration.

  20. Changing M3G/M6G ratios and pharmacodynamics in a cancer patient during long-term morphine treatment

    DEFF Research Database (Denmark)

    Andersen, Gertrud; Christrup, Lona Louring; Sjøgren, Per;


    A cancer patient receiving long-term oral sustained-release morphine treatment and periodically presenting with unusually high plasma M3G/M6G ratios is described. We found the patient's formation of M6G more unstable and perhaps delayed compared to the formation of M3G. There is no apparent...... explanation for this phenomenon and the high M3G/M6G ratios had no implications for the patient's pain experience or side effects from the morphine treatment....

  1. Evolution of Photospheric Flow and Magnetic Fields Associated with the 2015 June 22 M6.5 Flare (United States)

    Wang, Jiasheng; Liu, Chang; Deng, Na; Wang, Haimin


    The evolution of photospheric flow and magnetic fields before and after flares can provide important information regarding the flare triggering and back reaction processes. However, such studies on the flow field are rare due to the paucity of high-resolution observations covering the entire flaring period. Here we study the structural evolution of penumbra and shear flows associated with the 2015 June 22 M6.5 flare in NOAA AR 12371, using high-resolution imaging observation in the TiO band taken by the 1.6 m New Solar Telescope at Big Bear Solar Observatory, with the aid of the differential affine velocity estimator(DAVE) method for flow tracking. The accompanied photospheric vector magnetic field changes are also analyzed using data from the Helioseismic and Magnetic Imager. As a result, we found, for a penumbral segment in the negative field adjacent to the magnetic polarity inversion line (PIL), an enhancement of penumbral flows (up to ~2 km s-1) and extension of penumbral fibrils after the first peak of the flare hard X-ray (HXR) emission. We also found a shear flow region at the PIL, which is co-spatial with a precursor brightening kernel and exhibits a gradual increase of shear flow velocity (up to ~0.9 km s-1) after the flare. The enhancing penumbral and shear flow regions are also accompanied by an increase of horizontal field and decrease of magnetic inclination angle. These results are discussed in the context of the theory of back reaction of coronal restructuring on the photosphere as a result of flare energy release.

  2. Induced Seismicity: What is the Size of the Largest Expected Earthquake? (United States)

    Zoeller, G.; Holschneider, M.


    The injections of fluids is a well-known origin for the triggering of earthquake sequences. The growing number of projects related to enhanced geothermal systems, fracking and others has led to the question, which maximum earthquake magnitude can be expected as a consequence of fluid injection. This question is addressed from the perspective of statistical analysis. Using basic empirical laws of earthquake statistics, we estimate the magnitude MT of the maximum expected earthquake in a pre-defined future time window T. A case study of the fluid injection site at Paradox Valley, Colorado, USA, demonstrates that the magnitude m=4.3 of the largest observed earthquake on 27 May 2000 is lying very well within the expectation from past seismicity without adjusting any parameters. Vice versa, for a given maximum tolerable earthquake at an injection site, we can constrain the corresponding amount of injected fluids that must not be exceeded within pre-defined confidence bounds.

  3. Raising the science awareness of first year undergraduate students via an earthquake prediction seminar (United States)

    Gilstrap, T. D.


    post surveys are administered to measure students' understanding of and attitude towards earthquake prediction. End of class evaluations are administered as well and show positive attitudes of students towards earthquake research.

  4. Aquifers switched from confined to semiconfined by earthquakes (United States)

    Shi, Zheming; Wang, Guangcai


    Earthquake-induced aquifer parameter changes (e.g., permeability and hydraulic diffusivity) have been documented in many studies. However, changes in the confinement of an aquifer from confined to semiconfined following an earthquake have not been reported. Here we focus on the tidal response of the water level in four wells following the 2008 Wenchuan Mw 7.9 and 2013 Lushan Mw 6.6 earthquakes to show that earthquakes can change confined aquifers to semiconfined aquifers by reopening of preexisting vertical fractures (and later healing). This study has important implications because a switch from confined to semiconfined means a change of vertical hydraulic connection, which may affect the vulnerability of an aquifer, the integrity of underground waste repositories, and the safety of groundwater supplies.

  5. Mental health in L'Aquila after the earthquake

    Directory of Open Access Journals (Sweden)

    Paolo Stratta


    Full Text Available INTRODUCTION: In the present work we describe the mental health condition of L'Aquila population in the aftermath of the earthquake in terms of structural, process and outcome perspectives. METHOD: Literature revision of the published reports on the L'Aquila earthquake has been performed. RESULTS: Although important psychological distress has been reported by the population, capacity of resilience can be observed. However if resilient mechanisms intervened in immediate aftermath of the earthquake, important dangers are conceivable in the current medium-long-term perspective due to the long-lasting alterations of day-to-day life and the disruption of social networks that can be well associated with mental health problems. CONCLUSIONS: In a condition such as an earthquake, the immediate physical, medical, and emergency rescue needs must be addressed initially. However training first responders to identify psychological distress symptoms would be important for mental health triage in the field.

  6. Classification of Earthquake-triggered Landslide Events - Review of Classical and Particular Cases (United States)

    Braun, A.; Havenith, H. B.; Schlögel, R.


    Seismically induced landslides often contribute to a significant degree to the losses related to earthquakes. The identification of possible extends of landslide affected areas can help to target emergency measures when an earthquake occurs or improve the resilience of inhabited areas and critical infrastructure in zones of high seismic hazard. Moreover, landslide event sizes are an important proxy for the estimation of the intensity and magnitude of past earthquakes in paleoseismic studies, allowing us to improve seismic hazard assessment over longer terms. Not only earthquake intensity, but also factors such as the fault characteristics, topography, climatic conditions and the geological environment have a major impact on the intensity and spatial distribution of earthquake induced landslides. Inspired by classical reviews of earthquake induced landslides, e.g. by Keefer or Jibson, we present here a review of factors contributing to earthquake triggered slope failures based on an `event-by-event' classification approach. The objective of this analysis is to enable the short-term prediction of earthquake triggered landslide event sizes in terms of numbers and size of the affected area right after an earthquake event occurred. Five main factors, `Intensity', `Fault', `Topographic energy', `Climatic conditions' and `Surface geology' were used to establish a relationship to the number and spatial extend of landslides triggered by an earthquake. Based on well-documented recent earthquakes (e.g. Haiti 2010, Wenchuan 2008) and on older events for which reliable extensive information was available (e.g. Northridge 1994, Loma Prieta 1989, Guatemala 1976, Peru 1970) the combination and relative weight of the factors was calibrated. The calibrated factor combination was then applied to more than 20 earthquake events for which landslide distribution characteristics could be crosschecked. We present cases where our prediction model performs well and discuss particular cases

  7. A 'new generation' earthquake catalogue

    Directory of Open Access Journals (Sweden)

    E. Boschi


    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

  8. Earthquakes in Oita triggered by the 2016 M7.3 Kumamoto earthquake (United States)

    Yoshida, Shingo


    During the passage of the seismic waves from the M7.3 Kumamoto, Kyushu, earthquake on April 16, 2016, a M5.7 [semiofficial value estimated by the Japan Meteorological Agency (JMA)] event occurred in the central part of Oita prefecture, approximately 80 km far away from the mainshock. Although there have been a number of reports that M 5 triggered events. In this paper, we firstly confirm that this event is a M6-class event by re-estimating the magnitude using the strong-motion records of K-NET and KiK-net, and crustal deformation data at the Yufuin station observed by the Geospatial Information Authority of Japan. Next, by investigating the aftershocks of 45 mainshocks which occurred over the past 20 years based on the JMA earthquake catalog (JMAEC), we found that the delay time of the 2016 M5.7 event in Oita was the shortest. Therefore, the M5.7 event could be regarded as an exceptional M > 5 event that was triggered by passing seismic waves, unlike the usual triggered events and aftershocks. Moreover, a search of the JMAEC shows that in the 2016 Oita aftershock area, swarm earthquake activity was low over the past 30 years compared with neighboring areas. We also found that in the past, probably or possibly triggered events frequently occurred in the 2016 Oita aftershock area. The Oita area readily responds to remote triggering because of high geothermal activity and young volcanism in the area. The M5.7 Oita event was triggered by passing seismic waves, probably because large dynamic stress change was generated by the mainshock at a short distance and because the Oita area was already loaded to a critical stress state without a recent energy release as suggested by the past low swarm activity.[Figure not available: see fulltext.

  9. Evidence for external forcing temporal clustering of great earthquakes (United States)

    Khachikyan, Galina; Zhumabayev, Beibit; Toyshiev, Nursultan; Kairatkyzy, Dina; Kaldybayev, Azamat; Nurakynov, Serik


    It is shown by Bufe and Perkins [2005, BSSA, doi:10.1785/0120040110] and Shearera and Stark [2012, PNAS, doi: 10.1073/pnas.1118525109] that clustering of great earthquakes in 1950-1965 and 2004-2011 years is highly significant, with a 0.5% probability of random occurrence. Lutikov and Rogozhin [2014, Physics of the Solid Earth] reported on a similar clustering in the end of 19th - beginning of 20ty centuries as well, when strongest earthquakes occurred in Tien Shan (1889, M=8.3; and 1911, M=8.2); Alaska (1899, M=8.0); Kashgaria (1902, M=8.2); Mongolia (1905, M=8.2); San Francisco (1906, M=8.3), China(1906, M=8.3); Columbia (1906, M=8.6). Shearera and Stark [2012] have found that clustering of great earthquakes is analogous to seismic swarms that occur for a limited time. Simultaneously, they mentioned that at present no physical mechanism has been proposed to explain possible global seismicity swarms. Our results suggest that a mechanism responsible for temporal clustering of great earthquakes could be an external one related to the processes in the whole solar system including the Sun. We pay attention that the three marked periods of great earthquake clustering are related closely to the extreme phases of the recent Solar Centennial Gleissberg Cycle, which minimums occurred around of 1913 and 2008 years, and maximum - around of 1960 year. In particular, the great earthquake clustering in 1950-1965 coincides closely with the extremely high 19th eleven year solar cycle lasting from February 1954 to October 1964, while a great earthquake clustering after 2004 year coincides closely with the recent prolonged solar minimum developing after 2000 year. Also, we demonstrate that depending on the structure and composition of the lithosphere, strongest earthquakes may prefer to occur either in high or low solar activity. In particular, data analysis for 32 strongest (M=>7.0) earthquakes occurred in 1973-2014 years in the orogeny region of Eurasia, restricted by coordinates

  10. The Bay Area Earthquake Cycle:A Paleoseismic Perspective (United States)

    Schwartz, D. P.; Seitz, G.; Lienkaemper, J. J.; Dawson, T. E.; Hecker, S.; William, L.; Kelson, K.


    /SH/RC/NC/(SG?) sequence likely occurred subsequent to the penultimate San Andreas event. Although offset data, which reflect M, are limited, observations indicate that the penultimate SA event ruptured essentially the same fault length as 1906 (Schwartz et al, 1998). In addition, measured point-specific slip (RC, 1.8-2.3m; SG, 3.5-5m) and modeled average slip (SH, 1.9m) for the MREs indicate large magnitude earthquakes on the other regional faults. The major observation from the new paleoseismic data is that during a maximum interval of 176 years (1600 to 1776), significant seismic moment was released in the SFBR by large (M*6.7) surface-faulting earthquakes on the SA, RC, SH, NH, NC and possibly SG faults. This places an upper limit on the duration of San Andreas interaction effects (stress shadow) on the regional fault system. In fact, the interval between the penultimate San Andreas rupture and large earthquakes on other SFBR faults could have been considerably shorter. We are now 95 years out from the 1906 and the SFBR Working Group 99 probability time window extends to 2030, an interval of 124 years. The paleoearthquake data allow that within this amount of time following the penultimate San Andreas event one or more large earthquakes may have occurred on Bay Area faults. Longer paleoearthquake chronologies with more precise event dating in the SFBR and other locales provide the exciting potential for defining regional earthquake cycles and modeling long-term fault interactions.

  11. The Gibraltar Arc seismogenic zone (part 2): Constraints on a shallow east dipping fault plane source for the 1755 Lisbon earthquake provided by tsunami modeling and seismic intensity (United States)

    Gutscher, M.-A.; Baptista, M. A.; Miranda, J. M.


    The Great Lisbon earthquake has the largest documented felt area of any shallow earthquake and an estimated magnitude of 8.5-9.0. The associated tsunami ravaged the coast of SW Portugal and the Gulf of Cadiz, with run-up heights reported to have reached 5-15 m. While several source regions offshore SW Portugal have been proposed (e.g.— Gorringe Bank, Marquis de Pombal fault), no single source appears to be able to account for the great seismic moment as well as all the historical tsunami amplitude and travel time observations. A shallow east dipping fault plane beneath the Gulf of Cadiz associated with active subduction beneath Gibraltar, represents a candidate source for the Lisbon earthquake of 1755. Here we consider the fault parameters implied by this hypothesis, with respect to total slip, seismic moment, and recurrence interval to test the viability of this source. The geometry of the seismogenic zone is obtained from deep crustal studies and can be represented by an east dipping fault plane with mean dimensions of 180 km (N-S) × 210 km (E-W). For 10 m of co-seismic slip an Mw 8.64 event results and for 20 m of slip an Mw 8.8 earthquake is generated. Thus, for convergence rates of about 1 cm/yr, an event of this magnitude could occur every 1000-2000 years. Available kinematic and sedimentological data are in general agreement with such a recurrence interval. Tsunami wave form modeling indicates a subduction source in the Gulf of Cadiz can partly satisfy the historical observations with respect to wave amplitudes and arrival times, though discrepancies remain for some stations. A macroseismic analysis is performed using site effect functions calculated from isoseismals observed during instrumentally recorded strong earthquakes in the region (M7.9 1969 and M6.8 1964). The resulting synthetic isoseismals for the 1755 event suggest a subduction source, possibly in combination with an additional source at the NW corner of the Gulf of Cadiz can satisfactorily

  12. Photodynamic therapy: anti-tumour potentialities of bis (tri {pi}-hexyl-siloxy) silicon phthalocyanine against malignant achromic M6 melanocytes. EPR study of the photo-toxic mechanism; Phototherapie dynamique: etude des potentialites anti-tumorales de la bis (tri {pi}-hexylsiloxy) phtalocyanine de silicium sur melanocytes malins achromiques M6. Etude RPE desmecanismes phototoxiques

    Energy Technology Data Exchange (ETDEWEB)

    Decreau, R.; Viola, A.; Julliard, M. [Faculte des Sciences Saint-Jerome, 13 - Marseille (France). Laboratoire AM3-ESA CNRS; Hadjur, Ch.; Richard, M.J.; Favier, A. [Hopital Michallon, 38 - Grenoble (France). Laboratoire de Biochimie C; Jeunet, A. [Grenoble Universite, 38 - Saint-Martin-d' Heres (France). LEDSS-UMR CNRS


    Photodynamic therapy of cancerous cells is a technique relying upon the irradiation of tumorous cells after selective incorporation of a photo-sensitizer. The bis (tri n-hexyl-siloxy) silicon phthalocyanine is a second generation photo-sensitizer. Anti-cancerous potentialities of this molecule have been evaluated against the melanotic M6 cell line. Results have evidenced a high phototoxicity at low concentration and no dark toxicity under the same conditions. EPR studies on the photochemical pathways involved in phototoxicity processes have been realised in solvent and model membranes (liposomes). Results provide evidences for the production of singlet oxygen ({sup 1}O{sub 2}) as well as superoxide (O{sub 2}{sup 0-}) and hydroxyl radical ({sup 0}OH). (authors)

  13. Using Groundwater physiochemical properties for assessing potential earthquake precursor (United States)

    Inbar, Nimrod; Reuveni, Yuval; Anker, Yaakov; Guttman, Joseph


    Worldwide studies reports pre-seismic, co-seismic and post-seismic reaction of groundwater to earthquakes. The unique hydrological and geological situation in Israel resulted in relatively deep water wells which are located close to seismically active tectonic plate boundary. Moreover, the Israeli experience show that anomalies may occurs 60-90 minutes prior to the seismic event (Guttman et al., 2005; Anker et al., 2016). Here, we try to assess the possible connection between changes in physiochemical parameters of groundwater and earthquakes along the Dead Sea Transform (DST) region. A designated network of monitoring stations was installed in MEKOROT abandoned deep water wells, continuously measuring water table, conductivity and temperature at a sampling rate of 1 minute. Preliminary analysis compares changes in the measured parameters with rain events, tidal effects and earthquake occurrences of all measured magnitudes (>2.5Md) at monitoring area surroundings. The acquired data set over one year recorded simultaneous abrupt changes in several wells which seems disconnected from standard hydrological occurrences such as precipitation, abstraction or tidal effects. At this stage, our research aims to determine and rationalize a baseline for "normal response" of the measured parameters to external occurrences while isolating those cases in which "deviations" from that base line is recorded. We apply several analysis techniques both in time and frequency domain with the measured signal as well as statistical analysis of several measured earthquake parameters, which indicate potential correlations between earthquakes occurrences and the measured signal. We show that at least in one seismic event (5.1 Md) a potential precursor may have been recorded. Reference: Anker, Y., N. Inbar, A. Y. Dror, Y. Reuveni, J. Guttman, A. Flexer, (2016). Groundwater response to ground movements, as a tool for earthquakes monitoring and a possible precursor. 8th International Conference

  14. The 1992 Flores Earthquake Revisited: From Earthquake Source to Tsunami Inundation (United States)

    Latief, H.; Cummins, P. R.; Griffin, J.; Hossen, J.; Horspool, N.; Maher, N.; Fountain, L.; Hanung, R.; Rojali, A.; Kongko, W.


    The 1992 Flores earthquake (Mw=7.8) occurred on a back arc thrust near the island of Flores, Indonesia, causing widespread coastal uplift and subsidence, and generating a local tsunami with maximum runup height of over 25 meters that killed over 2,000 people. The event has been the subject of numerous publications on its various aspects, including the earthquake source mechanism determined from seismic data, and modelling of inundaiotn and tide gauge study data to study generation of the tsunami. To date, however, no studies have quantitatively assessed the constraints placed on the source mechanism by all the different types of data - seismic, geodetic and tsunami tide gauge waveforms and inundation. The opportunity to greatly improve the latter has presented itself recently through the availability of a high-resolution LiDAR data set for the topography along coastal strip near the earthquake. In this study we have undertaken a joint inversion of seismic and geodetic data available from this earthquake, and compared the results obtained to tsunami inundation and tide gauge data. We will present an assessment of what constraints the different data types place on the source mechanism, and how well these are compatible with the observed tsunami inundation results. Preliminary results suggest that the roughly 2 m inundation near Maumere is well explained, but the extreme tsunami run-up at Riang Kroko is not

  15. Stduy on White rot fungi (m-6) lignin enzyme activity in the W/O microemlsion%油包水(W/O)型微乳液中m-6菌木质素降解酶的研究

    Institute of Scientific and Technical Information of China (English)

    李娜; 冯贵颖; 刘晓风; 袁月祥; 闫志英; 贺蓉娜; 廖银章


    [目的]研究W/O十六烷基三甲基溴化铵(CTAB)微乳液体系和HAc-NaAc缓冲液体系中,m-6菌株固态发酵后产生的胞外木质素降解酶漆酶(Lac)、木质素过氧化物酶(Lip)、锰过氧化物酶(Mnp)酶促反应的最佳反应条件.[方法]通过分别对Lip(以2,2′-连氮-二(3-乙苯基并噻唑-磺酸)为底物)、Mnp(以MnSO4>为底物)和Lac(以藜芦醇为底物)3种木质素降解酶在W/O型CTAB微乳液体系和HAc-NaAc缓冲液体系中的酶活测定,研究不同温度、pH和底物浓度对酶促反应的影响,探讨最佳反应条件,并比较两种反应体系下的酶活.[结果]在W/O型CTAB微乳液体系中,Lip、Mnp和Lac 3种酶酶促反应的最佳条件为:温度37℃、pH分别为4.5,4.5和3.5;在HAc-NaAc缓冲液体系中,3种酶酶促反应的最佳反应条件为:温度37℃,pH分别为5.0,5.0和4.0;在两种反应体系中的最佳反应底物浓度相同,即藜芦醇、MnSO4>、2,2′-连氮-二(3-乙苯基并噻唑-磺酸)浓度分别为0.053,0.116,0.492 mmol/L.在W/O型CTAB微乳液中,Lip和Mnp酶活比其在HAc-NaAc缓冲液体系中分别提高了81.45%和36.75%,但Lac酶活却减少了2.914倍.[结论]得到了Lac、Lip和Mnp酶3种木质素降解酶在W/O型CTAB微乳液体系和HAc-NaAc缓冲液体系中的最佳反应条件,为木质纤维素的生物降解奠定了基础.

  16. Food, water, and fault lines: Remote sensing opportunities for earthquake-response management of agricultural water

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez, Jenna, E-mail:; Ustin, Susan; Sandoval-Solis, Samuel; O' Geen, Anthony Toby


    Earthquakes often cause destructive and unpredictable changes that can affect local hydrology (e.g. groundwater elevation or reduction) and thus disrupt land uses and human activities. Prolific agricultural regions overlie seismically active areas, emphasizing the importance to improve our understanding and monitoring of hydrologic and agricultural systems following a seismic event. A thorough data collection is necessary for adequate post-earthquake crop management response; however, the large spatial extent of earthquake's impact makes challenging the collection of robust data sets for identifying locations and magnitude of these impacts. Observing hydrologic responses to earthquakes is not a novel concept, yet there is a lack of methods and tools for assessing earthquake's impacts upon the regional hydrology and agricultural systems. The objective of this paper is to describe how remote sensing imagery, methods and tools allow detecting crop responses and damage incurred after earthquakes because a change in the regional hydrology. Many remote sensing datasets are long archived with extensive coverage and with well-documented methods to assess plant-water relations. We thus connect remote sensing of plant water relations to its utility in agriculture using a post-earthquake agrohydrologic remote sensing (PEARS) framework; specifically in agro-hydrologic relationships associated with recent earthquake events that will lead to improved water management. - Highlights: • Remote sensing to improve agricultural disaster management • Introduce post-earthquake agrohydrologic remote sensing (PEARS) framework • Apply PEARS framework to 2010 Maule Earthquake in Central Chile.

  17. Distribution characteristics of historical earthquake classes in Jiangsu Province and South Huanghai Sea region

    Institute of Scientific and Technical Information of China (English)

    田建明; 徐徐; 谢华章; 杨云; 丁政


    According to the analysis on the characteristics of historic earthquakes in Jiangsu Province and South Huanghai Sea region, the historical earthquakes in the studied area are divided into two kinds of"comparatively safe class"and"comparatively dangerous class". Then the statistical result of earthquake class, the characteristics of geographical distribution and geological structures are studied. The study shows: a) In Jiangsu Province and South Huanghai Sea region, the majority of historical strong earthquakes belong to"comparatively safe class", only 13.8% belong to"comparatively dangerous class"; b) Most historical earthquakes belong to"comparatively safe class" in the land area of Jiangsu, eastern sea area of Yangtze River mouth and northern depression of South Huanghai Sea region. However, along the coast of middle Jiangsu Province and in the sea area of South Huanghai Sea, the distribution of historical earthquake classes is complex and the earthquake series of"comparatively dangerous class"and"comparatively safe class"are equivalent in number; c) In the studied area, the statistical results of historical earthquake classes and the characteristics of spatial distribution accord very well with the real case of present-day earthquake series. It shows that the seismic activity in the region has the characteristic of succession, and the result from this study can be used as a reference for early postseismic judgment in the earthquake emergency work in Jiangsu Province.

  18. Possible cause for an improbable earthquake: The 1997 MW 4.9 southern Alabama earthquake and hydrocarbon recovery (United States)

    Gomberg, J.; Wolf, L.


    Circumstantial and physical evidence indicates that the 1997 MW 4.9 earthquake in southern Alabama may have been related to hydrocarbon recovery. Epicenters of this earthquake and its aftershocks were located within a few kilometers of active oil and gas extraction wells and two pressurized injection wells. Main shock and aftershock focal depths (2-6 km) are within a few kilometers of the injection and withdrawal depths. Strain accumulation at geologic rates sufficient to cause rupture at these shallow focal depths is not likely. A paucity of prior seismicity is difficult to reconcile with the occurrence of an earthquake of MW 4.9 and a magnitude-frequency relationship usually assumed for natural earthquakes. The normal-fault main-shock mechanism is consistent with reactivation of preexisting faults in the regional tectonic stress field. If the earthquake were purely tectonic, however, the question arises as to why it occurred on only the small fraction of a large, regional fault system coinciding with active hydrocarbon recovery. No obvious temporal correlation is apparent between the earthquakes and recovery activities. Although thus far little can be said quantitatively about the physical processes that may have caused the 1997 sequence, a plausible explanation involves the poroelastic response of the crust to extraction of hydrocarbons.

  19. Possible cause for an improbable earthquake: The 1997 Mw 4.9 southern Alabama earthquake and hydrocarbon recovery (United States)

    Gomberg, Joan; Wolf, Lorraine


    Circumstantial and physical evidence indicates that the 1997 Mw 4.9 earthquake in southern Alabama may have been related to hydrocarbon recovery. Epicenters of this earthquake and its aftershocks were located within a few kilometers of active oil and gas extraction wells and two pressurized injection wells. Main shock and aftershock focal depths (2 6 km) are within a few kilometers of the injection and withdrawal depths. Strain accumulation at geologic rates sufficient to cause rupture at these shallow focal depths is not likely. A paucity of prior seismicity is difficult to reconcile with the occurrence of an earthquake of Mw 4.9 and a magnitude-frequency relationship usually assumed for natural earthquakes. The normal-fault main-shock mechanism is consistent with reactivation of preexisting faults in the regional tectonic stress field. If the earthquake were purely tectonic, however, the question arises as to why it occurred on only the small fraction of a large, regional fault system coinciding with active hydrocarbon recovery. No obvious temporal correlation is apparent between the earthquakes and recovery activities. Although thus far little can be said quantitatively about the physical processes that may have caused the 1997 sequence, a plausible explanation involves the poroelastic response of the crust to extraction of hydrocarbons.

  20. Hanford wells

    Energy Technology Data Exchange (ETDEWEB)

    McGhan, V.L.; Damschen, D.W.


    The Hanford Site contains about 2200 wells constructed from pre-Hanford Works days to the present. As of June 1977, about 1900 wells still exist, and about 850 of these existing wells were drilled to the ground-water table. About 700 of these wells (including about 24 farm wells) still contain water. The others have become dry through infiltration of sediments or a general lowering of the water table in their vicinity. This report, providing the most complete documentation of wells in and adjacent to the Hanford Site, supersedes all previous compilations of Hanford wells.

  1. Earthquakes Threaten Many American Schools (United States)

    Bailey, Nancy E.


    Millions of U.S. children attend schools that are not safe from earthquakes, even though they are in earthquake-prone zones. Several cities and states have worked to identify and repair unsafe buildings, but many others have done little or nothing to fix the problem. The reasons for ignoring the problem include political and financial ones, but…

  2. Make an Earthquake: Ground Shaking! (United States)

    Savasci, Funda


    The main purposes of this activity are to help students explore possible factors affecting the extent of the damage of earthquakes and learn the ways to reduce earthquake damages. In these inquiry-based activities, students have opportunities to develop science process skills and to build an understanding of the relationship among science,…

  3. Make an Earthquake: Ground Shaking! (United States)

    Savasci, Funda


    The main purposes of this activity are to help students explore possible factors affecting the extent of the damage of earthquakes and learn the ways to reduce earthquake damages. In these inquiry-based activities, students have opportunities to develop science process skills and to build an understanding of the relationship among science,…

  4. Anthropogenic triggering of large earthquakes. (United States)

    Mulargia, Francesco; Bizzarri, Andrea


    The physical mechanism of the anthropogenic triggering of large earthquakes on active faults is studied on the basis of experimental phenomenology, i.e., that earthquakes occur on active tectonic faults, that crustal stress values are those measured in situ and, on active faults, comply to the values of the stress drop measured for real earthquakes, that the static friction coefficients are those inferred on faults, and that the effective triggering stresses are those inferred for real earthquakes. Deriving the conditions for earthquake nucleation as a time-dependent solution of the Tresca-Von Mises criterion applied in the framework of poroelasticity yields that active faults can be triggered by fluid overpressures oil and gas production and storage may trigger destructive earthquakes on active faults at a few tens of kilometers. Fluid pressure propagates as slow stress waves along geometric paths operating in a drained condition and can advance the natural occurrence of earthquakes by a substantial amount of time. Furthermore, it is illusory to control earthquake triggering by close monitoring of minor "foreshocks", since the induction may occur with a delay up to several years.

  5. Heavy tails and earthquake probabilities (United States)

    Ellsworth, William L.


    The 21st century has already seen its share of devastating earthquakes, some of which have been labeled as “unexpected,” at least in the eyes of some seismologists and more than a few journalists. A list of seismological surprises could include the 2004 Sumatra-Andaman Islands; 2008 Wenchuan, China; 2009 Haiti; 2011 Christchurch, New Zealand; and 2011 Tohoku, Japan, earthquakes

  6. Earthquakes Threaten Many American Schools (United States)

    Bailey, Nancy E.


    Millions of U.S. children attend schools that are not safe from earthquakes, even though they are in earthquake-prone zones. Several cities and states have worked to identify and repair unsafe buildings, but many others have done little or nothing to fix the problem. The reasons for ignoring the problem include political and financial ones, but…

  7. Can Satellites Aid Earthquake Predictions?

    Institute of Scientific and Technical Information of China (English)

    John Roach; 李晓辉


    @@ Earthquake prediction is an imprecise science, and to illustrate the point,many experts point to the story of Tangshen①, China. On July 28, 1976, a magnitude② 7. 6 earthquake struck the city of Tangshen, China, without warning. None of the signs of the successful prediction from a year and half earlier were present. An estimated 250,000 people died.

  8. Anomalous decrease in relatively large shocks and increase in the p and b values preceding the April 16, 2016, M7.3 earthquake in Kumamoto, Japan (United States)

    Nanjo, K. Z.; Yoshida, A.


    The 2016 Kumamoto earthquakes in Kyushu, Japan, started with a magnitude ( M) 6.5 quake on April 14 on the Hinagu fault zone (FZ), followed by active seismicity including an M6.4 quake. Eventually, an M7.3 quake occurred on April 16 on the Futagawa FZ. We investigated if any sign indicative of the M7.3 quake could be found in the space-time changes in seismicity after the M6.5 quake. As a quality control, we determined in advance the threshold magnitude, above which all earthquakes are completely recorded. We then showed that the occurrence rate of relatively large ( M ≥ 3) earthquakes significantly decreased 1 day before the M7.3 quake. Significance of this decrease was evaluated by one standard deviation of sampled changes in the rate of occurrence. We next confirmed that seismicity with M ≥ 3 was well modeled by the Omori-Utsu law with p 1.5 ± 0.3, which indicates that the temporal decay of seismicity was significantly faster than a typical decay with p = 1. The larger p value was obtained when we used data of the longer time period in the analysis. This significance was confirmed by a bootstrapping approach. Our detailed analysis shows that the large p value was caused by the rapid decay of the seismicity in the northern area around the Futagawa FZ. Application of the slope (the b value) of the Gutenberg-Richter frequency-magnitude distribution to the spatiotemporal change in the seismicity revealed that the b value in the northern area increased significantly, the increase being Δ b = 0.3-0.5. Significance was verified by a statistical test of Δ b and a test using bootstrapping errors. Based on our findings, combined with the results obtained by a stress inversion analysis performed by the National Research Institute for Earth Science and Disaster Resilience, we suggested that stress near the Futagawa FZ had reduced just prior to the occurrence of the M7.3 quake. We proposed, with some other observations, that a reduction in stress might have been

  9. Well Spacing for Horizontal Wells

    Directory of Open Access Journals (Sweden)

    C.D.S. Keuengoua


    Full Text Available In the developing phase of a hydrocarbon reservoir and planning for drilling the production wells, it is necessary to drill the wells in an appropriate spacing to achieve maximum economic revenues during the reservoir life span. Well spacing which is the real location and interrelationship between producing oil or gas wells in an oil field is an important parameter. It is determined for the maximum ultimate production of a given reservoir and should be taken in consideration during well planning to avoid drilling of unnecessary wells. This study presents the concept of drainage area on horizontal well and horizontal productivity indices with different equations and their applications. A user friendly Excel Spreadsheet program was developed to calculate the productivity values of horizontal wells using three major available productivity equations. Also, the developed spreadsheet program was used to evaluate the effect of well spacing on the productivities of horizontal wells using productivity index approach and drainage area concept. It also helps to review the comparison between vertical and horizontal wells spacing based on drainage area concept. This program was validated, and then was used to study the effect of horizontal well length on the ratio of horizontal well productivity to vertical well productivity. The results show that higher ratio of horizontal well productivity to vertical well productivity values are obtained with increase length of the horizontal well. It is a very useful tool for making decision about the application of well spacing for horizontal wells.

  10. Testing earthquake source inversion methodologies

    KAUST Repository

    Page, Morgan T.


    Source Inversion Validation Workshop; Palm Springs, California, 11-12 September 2010; Nowadays earthquake source inversions are routinely performed after large earthquakes and represent a key connection between recorded seismic and geodetic data and the complex rupture process at depth. The resulting earthquake source models quantify the spatiotemporal evolution of ruptures. They are also used to provide a rapid assessment of the severity of an earthquake and to estimate losses. However, because of uncertainties in the data, assumed fault geometry and velocity structure, and chosen rupture parameterization, it is not clear which features of these source models are robust. Improved understanding of the uncertainty and reliability of earthquake source inversions will allow the scientific community to use the robust features of kinematic inversions to more thoroughly investigate the complexity of the rupture process and to better constrain other earthquakerelated computations, such as ground motion simulations and static stress change calculations.

  11. Earthquake forecasting: statistics and information

    Directory of Open Access Journals (Sweden)

    Vladimir Gertsik


    Full Text Available The paper presents a decision rule forming a mathematical basis of earthquake forecasting problem. We develop an axiomatic approach to earthquake forecasting in terms of multicomponent random fields on a lattice. This approach provides a method for constructing point estimates and confidence intervals for conditional probabilities of strong earthquakes under conditions on the levels of precursors. Also, it provides an approach for setting a multilevel alarm system and hypothesis testing for binary alarms. We use a method of comparison for different algorithms of earthquake forecasts in terms of the increase of Shannon information. ‘Forecasting’ (the calculation of the probabilities and ‘prediction’ (the alarm declaring of earthquakes are equivalent in this approach.

  12. Are Earthquakes a Critical Phenomenon? (United States)

    Ramos, O.


    Earthquakes, granular avalanches, superconducting vortices, solar flares, and even stock markets are known to evolve through power-law distributed events. During decades, the formalism of equilibrium phase transition has coined these phenomena as critical, which implies that they are also unpredictable. This work revises these ideas and uses earthquakes as the paradigm to demonstrate that slowly driven systems evolving through uncorrelated and power-law distributed avalanches (UPLA) are not necessarily critical systems, and therefore not necessarily unpredictable. By linking the correlation length to the pdf of the distribution, and comparing it with the one obtained at a critical point, a condition of criticality is introduced. Simulations in the classical Olami-Feder-Christensen (OFC) earthquake model confirm the findings, showing that earthquakes are not a critical phenomenon. However, one single catastrophic earthquake may show critical properties and, paradoxically, the emergence of this temporal critical behaviour may eventually carry precursory signs of catastrophic events.

  13. Earthquake Activity in the North Greenland Region (United States)

    Larsen, Tine B.; Dahl-Jensen, Trine; Voss, Peter H.


    Many local and regional earthquakes are recorded on a daily basis in northern Greenland. The majority of the earthquakes originate at the Arctic plate boundary between the Eurasian and the North American plates. Particularly active regions away from the plate boundary are found in NE Greenland and in northern Baffin Bay. The seismograph coverage in the region is sparse with the main seismograph stations located at the military outpost, Stations Nord (NOR), the weather station outpost Danmarkshavn (DAG), Thule Airbase (TULEG), and the former ice core drilling camp (NEEM) in the middle of the Greenland ice sheet. Furthermore, data is available from Alert (ALE), Resolute (RES), and other seismographs in northern Canada as well as from a temporary deployment of BroadBand seismographs along the north coast of Greenland from 2004 to 2007. The recorded earthquakes range in magnitude from less than 2 to a 4.8 event, the largest in NE Greenland, and a 5.7 event, the largest recorded in northern Baffin Bay. The larger events are recorded widely in the region allowing for focal mechanisms to be calculated. Only a few existing focal mechanisms for the region can be found in the ISC bulletin. Two in NE Greenland representing primarily normal faulting and one in Baffin Bay resulting from reverse faulting. New calculations of focal mechanisms for the region will be presented as well as improved hypocenters resulting from analysis involving temporary stations and regional stations that are not included in routine processing.

  14. Christchurch earthquakes: how did former refugees cope? (United States)

    Osman, Mohamud; Hornblow, Andrew; Macleod, Sandy; Coope, Pat


    This study investigated how former refugees now living in Christchurch (Canterbury Province, New Zealand) communities coped after the 4 September 2010 and subsequent earthquakes. A systematic sample of one in three former refugees from five ethnic groupings (Afghanistan, Kurdistan, Ethiopia, Somalia and Bhutan) was selected from a list of 317 refugees provided by the Canterbury Refugee Council and invited to participate in the study. Seventy-two out of 105 potential participants completed a 26 item questionnaire regarding the impact of the quakes, their concerns and anxieties, coping strategies and social supports. The methodology was complicated by ongoing aftershocks, particularly that of 22 February 2011. Three-quarters of participants reported that they had coped well, spirituality and religious practice being an important support for many, despite less then 20% receiving support from mainstream agencies. Most participants (72%) had not experienced a traumatic event or natural disaster before. Older participants and married couples with children were more likely to worry about the earthquakes and their impact than single individuals. There was a significant difference in the level of anxiety between males and females. Those who completed the questionnaire after the 22 February 2011 quake were more worried overall than those interviewed before this. Overall, the former refugees reported they had coped well despite most of them not experiencing an earthquake before and few receiving support from statutory relief agencies. More engagement from local services is needed in order to build trust and cooperation between the refugee and local communities.

  15. Gamra: Simple Meshes for Complex Earthquakes

    CERN Document Server

    Landry, Walter


    The static offsets caused by earthquakes are well described by elastostatic models with a discontinuity in the displacement along the fault. A traditional approach to model this discontinuity is to align the numerical mesh with the fault and solve the equations using finite elements. However, this distorted mesh can be difficult to generate and update. We present a new numerical method, inspired by the Immersed Interface Method, for solving the elastostatic equations with embedded discontinuities. This method has been carefully designed so that it can be used on parallel machines on an adapted finite difference grid. We have implemented this method in Gamra, a new code for earth modelling. We demonstrate the correctness of the method with analytic tests, and we demonstrate its practical performance by solving a realistic earthquake model to extremely high precision.

  16. The CATDAT damaging earthquakes database

    Directory of Open Access Journals (Sweden)

    J. E. Daniell


    Full Text Available The global CATDAT damaging earthquakes and secondary effects (tsunami, fire, landslides, liquefaction and fault rupture database was developed to validate, remove discrepancies, and expand greatly upon existing global databases; and to better understand the trends in vulnerability, exposure, and possible future impacts of such historic earthquakes.

    Lack of consistency and errors in other earthquake loss databases frequently cited and used in analyses was a major shortcoming in the view of the authors which needed to be improved upon.

    Over 17 000 sources of information have been utilised, primarily in the last few years, to present data from over 12 200 damaging earthquakes historically, with over 7000 earthquakes since 1900 examined and validated before insertion into the database. Each validated earthquake includes seismological information, building damage, ranges of social losses to account for varying sources (deaths, injuries, homeless, and affected, and economic losses (direct, indirect, aid, and insured.

    Globally, a slightly increasing trend in economic damage due to earthquakes is not consistent with the greatly increasing exposure. The 1923 Great Kanto ($214 billion USD damage; 2011 HNDECI-adjusted dollars compared to the 2011 Tohoku (>$300 billion USD at time of writing, 2008 Sichuan and 1995 Kobe earthquakes show the increasing concern for economic loss in urban areas as the trend should be expected to increase. Many economic and social loss values not reported in existing databases have been collected. Historical GDP (Gross Domestic Product, exchange rate, wage information, population, HDI (Human Development Index, and insurance information have been collected globally to form comparisons.

    This catalogue is the largest known cross-checked global historic damaging earthquake database and should have far-reaching consequences for earthquake loss estimation, socio-economic analysis, and the global

  17. Breaking the oceanic lithosphere of a subducting slab: the 2013 Khash, Iran earthquake (United States)

    Barnhart, William D.; Hayes, Gavin P.; Samsonov, S.; Fielding, E.; Seidman, L.


    [1] Large intermediate depth, intraslab normal faulting earthquakes are a common, dangerous, but poorly understood phenomenon in subduction zones owing to a paucity of near field geophysical observations. Seismological and high quality geodetic observations of the 2013 Mw7.7 Khash, Iran earthquake reveal that at least half of the oceanic lithosphere, including the mantle and entire crust, ruptured in a single earthquake, confirming with unprecedented resolution that large earthquakes can nucleate in and rupture through the oceanic mantle. A rupture width of at least 55 km is required to explain both InSAR observations and teleseismic waveforms, with the majority of slip occurring in the oceanic mantle. Combining our well-constrained earthquake slip distributions with the causative fault orientation and geometry of the local subduction zone, we hypothesize that the Khash earthquake likely occurred as the combined result of slab bending forces and dehydration of hydrous minerals along a preexisting fault formed prior to subduction.

  18. Short-Term Forecasting of Taiwanese Earthquakes Using a Universal Model of Fusion-Fission Processes (United States)

    Cheong, Siew Ann; Tan, Teck Liang; Chen, Chien-Chih; Chang, Wu-Lung; Liu, Zheng; Chew, Lock Yue; Sloot, Peter M. A.; Johnson, Neil F.


    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

  19. Short-term forecasting of Taiwanese earthquakes using a universal model of fusion-fission processes. (United States)

    Cheong, Siew Ann; Tan, Teck Liang; Chen, Chien-Chih; Chang, Wu-Lung; Liu, Zheng; Chew, Lock Yue; Sloot, Peter M A; Johnson, Neil F


    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.

  20. The HayWired earthquake scenario (United States)

    Detweiler, Shane T.; Wein, Anne M.


    ForewordThe 1906 Great San Francisco earthquake (magnitude 7.8) and the 1989 Loma Prieta earthquake (magnitude 6.9) each motivated residents of the San Francisco Bay region to build countermeasures to earthquakes into the fabric of the region. Since Loma Prieta, bay-region communities, governments, and utilities have invested tens of billions of dollars in seismic upgrades and retrofits and replacements of older buildings and infrastructure. Innovation and state-of-the-art engineering, informed by science, including novel seismic-hazard assessments, have been applied to the challenge of increasing seismic resilience throughout the bay region. However, as long as people live and work in seismically vulnerable buildings or rely on seismically vulnerable transportation and utilities, more work remains to be done.With that in mind, the U.S. Geological Survey (USGS) and its partners developed the HayWired scenario as a tool to enable further actions that can change the outcome when the next major earthquake strikes. By illuminating the likely impacts to the present-day built environment, well-constructed scenarios can and have spurred officials and citizens to take steps that change the outcomes the scenario describes, whether used to guide more realistic response and recovery exercises or to launch mitigation measures that will reduce future risk.The HayWired scenario is the latest in a series of like-minded efforts to bring a special focus onto the impacts that could occur when the Hayward Fault again ruptures through the east side of the San Francisco Bay region as it last did in 1868. Cities in the east bay along the Richmond, Oakland, and Fremont corridor would be hit hardest by earthquake ground shaking, surface fault rupture, aftershocks, and fault afterslip, but the impacts would reach throughout the bay region and far beyond. The HayWired scenario name reflects our increased reliance on the Internet and telecommunications and also alludes to the

  1. Testing for Changes in Crustal Velocity at the Tocopilla Earthquake, Northern Chile (United States)

    Richter, T.; Asch, G.; Kind, R.


    We use two different techniques to investigate the region between Antofagasta and Arica in northern Chile for crustal velocity changes. Data are taken from the 19 broadband stations of the IPOC project (Integrated Plate Boundary Observatory Chile) operating partly since 2006 by GFZ and Institut de Physique du Globe de Paris (IPGP). In the neighborhood of the seismic stations an M7.0 earthquake occurred near Tocopilla on 14 November 2007. Other studies have shown that in the course of such earthquakes seismic velocities may be changing (e.g. Brenguier et al. 2008). The first method is testing for phase shifts in receiver functions. To avoid varying travel paths of different events we compare events located in small source regions. Although temporal variations have been found in receiver functions for the Parkfield M6.0 and San Simeon M6.5 earthquakes (Audet 2006) we cannot find any variations exceeding the noise level of our dataset at the time of the M7.0 earthquake near Tocopilla. Therefore the data is analyzed with the help of cross-correlation technique of ambient seismic noise (Bensen et al. 2007). Compared to the first method it has the advantage of regularly available correlation functions (e.g. 1 per day). We report on first results.

  2. The 2015 Gorkha Nepal Earthquake: Insights from Earthquake Damage Survey

    Directory of Open Access Journals (Sweden)

    Katsuichiro eGoda


    Full Text Available The 2015 Gorkha Nepal earthquake caused tremendous damage and loss. To gain valuable lessons from this tragic event, an earthquake damage investigation team was dispatched to Nepal from 1 May 2015 to 7 May 2015. A unique aspect of the earthquake damage investigation is that first-hand earthquake damage data were obtained 6 to 11 days after the mainshock. To gain deeper understanding of the observed earthquake damage in Nepal, the paper reviews the seismotectonic setting and regional seismicity in Nepal and analyzes available aftershock data and ground motion data. The earthquake damage observations indicate that the majority of the damaged buildings were stone/brick masonry structures with no seismic detailing, whereas the most of RC buildings were undamaged. This indicates that adequate structural design is the key to reduce the earthquake risk in Nepal. To share the gathered damage data widely, the collected damage data (geo-tagged photos and observation comments are organized using Google Earth and the kmz file is made publicly available.

  3. Simulation Based Earthquake Forecasting with RSQSim (United States)

    Gilchrist, J. J.; Jordan, T. H.; Dieterich, J. H.; Richards-Dinger, K. B.


    We are developing a physics-based forecasting model for earthquake ruptures in California. We employ the 3D boundary element code RSQSim to generate synthetic catalogs with millions of events that span up to a million years. The simulations incorporate rate-state fault constitutive properties in complex, fully interacting fault systems. The Unified California Earthquake Rupture Forecast Version 3 (UCERF3) model and data sets are used for calibration of the catalogs and specification of fault geometry. Fault slip rates match the UCERF3 geologic slip rates and catalogs are tuned such that earthquake recurrence matches the UCERF3 model. Utilizing the Blue Waters Supercomputer, we produce a suite of million-year catalogs to investigate the epistemic uncertainty in the physical parameters used in the simulations. In particular, values of the rate- and state-friction parameters a and b, the initial shear and normal stress, as well as the earthquake slip speed, are varied over several simulations. In addition to testing multiple models with homogeneous values of the physical parameters, the parameters a, b, and the normal stress are varied with depth as well as in heterogeneous patterns across the faults. Cross validation of UCERF3 and RSQSim is performed within the SCEC Collaboratory for Interseismic Simulation and Modeling (CISM) to determine the affect of the uncertainties in physical parameters observed in the field and measured in the lab, on the uncertainties in probabilistic forecasting. We are particularly interested in the short-term hazards of multi-event sequences due to complex faulting and multi-fault ruptures.

  4. Biological Anomalies around the 2009 L'Aquila Earthquake. (United States)

    Fidani, Cristiano


    The April 6, 2009 L'Aquila earthquake was the strongest seismic event to occur in Italy over the last thirty years with a magnitude of M = 6.3. Around the time of the seismic swarm many instruments were operating in Central Italy, even if not dedicated to biological effects associated with the stress field variations, including seismicity. Testimonies were collected using a specific questionnaire immediately after the main shock, including data on earthquake lights, gas leaks, human diseases, and irregular animal behavior. The questionnaire was made up of a sequence of arguments, based upon past historical earthquake observations and compiled over seven months after the main shock. Data on animal behavior, before, during and after the main shocks, were analyzed in space/time distributions with respect to the epicenter area, evidencing the specific responses of different animals. Several instances of strange animal behavior were observed which could causally support the hypotheses that they were induced by the physical presence of gas, electric charges and electromagnetic waves in atmosphere. The aim of this study was to order the biological observations and thereby allow future work to determine whether these observations were influenced by geophysical parameters.

  5. Rapid GNSS and Data Communication System Deployments In Chile and Argentina Following the M8.8 Maule Earthquake (United States)

    Blume, F.; Meertens, C. M.; Brooks, B. A.; Bevis, M. G.; Smalley, R.; Parra, H.; Baez, J.


    in the epicentral area. UNAVCO has developed and deplyed standalone data communications systems at 25 of the stations: (1) the satellite-based Inmarsat Broad Global Area Service (BGAN), (2) ground based cellular internet services provided by a number of telecom companies in Chile and Argentina. Cellular service is economical but prone to disruptions following earthquakes and coverage is limited. BGAN is expensive but robust and globally available. This communication plan has allowed for daily downloads of 15 sec. data and of 1 sec. data recorded during aftershocks of M6.5 and greater. RINEX files from these stations are publicly available at the UNAVCO Facility Archive immediately after data are downloaded, a first for Event Response GPS data. This effort will serve as the type example in the geodetic community for rapid CGPS data communications following a destructive earthquake. The communications system hardware purchased during this response will become part of the UNAVCO pool after one year and will be available for future PI projects and event responses.

  6. The Alaska earthquake, March 27, 1964: lessons and conclusions (United States)

    Eckel, Edwin B.


    subsidence was superimposed on regional tectonic subsidence to heighten the flooding damage. Ground and surface waters were measurably affected by the earthquake, not only in Alaska but throughout the world. Expectably, local geologic conditions largely controlled the extent of structural damage, whether caused directly by seismic vibrations or by secondary effects such as those just described. Intensity was greatest in areas underlain by thick saturated unconsolidated deposits, least on indurated bedrock or permanently frozen ground, and intermediate on coarse well-drained gravel, on morainal deposits, or on moderately indurated sedimentary rocks. Local and even regional geology also controlled the distribution and extent of the earthquake's effects on hydrologic systems. In the conterminous United States, for example, seiches in wells and bodies of surface water were controlled by geologic structures of regional dimension. Devastating as the earthquake was, it had many long-term beneficial effects. Many of these were socioeconomic or engineering in nature; others were of scientific value. Much new and corroborative basic geologic and hydrologic information was accumulated in the course of the earthquake studies, and many new or improved investigative techniques were developed. Chief among these, perhaps, were the recognition that lakes can be used as giant tiltmeters, the refinement of methods for measuring land-level changes by observing displacements of barnacles and other sessile organisms, and the relating of hydrology to seismology by worldwide study of hydroseisms in surface-water bodies and in wells. The geologic and hydrologic lessons learned from studies of the Alaska earthquake also lead directly to better definition of the research needed to further our understanding of earthquakes and of how to avoid or lessen the effects of future ones. Research is needed on the origins and mechanisms of earthquakes, on crustal structure, and on the generation of tsunamis and

  7. Subdiffusion of volcanic earthquakes

    CERN Document Server

    Abe, Sumiyoshi


    A comparative study is performed on volcanic seismicities at Mt.Eyjafjallajokull in Iceland and Mt. Etna in Sicily, Italy, from the viewpoint of science of complex systems, and the discovery of remarkable similarities between them regarding their exotic spatio-temporal properties is reported. In both of the volcanic seismicities as point processes, the jump probability distributions of earthquakes are found to obey the exponential law, whereas the waiting-time distributions follow the power law. In particular, a careful analysis is made about the finite size effects on the waiting-time distributions, and accordingly, the previously reported results for Mt. Etna [S. Abe and N. Suzuki, EPL 110, 59001 (2015)] are reinterpreted. It is shown that spreads of the volcanic earthquakes are subdiffusive at both of the volcanoes. The aging phenomenon is observed in the "event-time-averaged" mean-squared displacements of the hypocenters. A comment is also made on presence/absence of long term memories in the context of t...

  8. Improving Earthquake Stress Drop Measurements - What can we Really Resolve? (United States)

    Abercrombie, R. E.; Bannister, S. C.; Fry, B.; Ruhl, C. J.; Kozlowska, M.


    Earthquake stress drop is fundamental to understanding the physics of the rupture process. Although it is superficially simple to calculate an estimate of stress drop from the corner frequency of the radiated spectrum, it is much harder to be certain that measurements are reliable and accurate. The same is true of other measurements of stress drop and radiated energy. The large number of studies of earthquake stress drop, the high variability in results (~0.1-100 MPa), the large uncertainties, and the ongoing scaling controversy are evidence for this. We investigate the resolution and uncertainties of stress drops calculated using an empirical Green's function (EGF) approach. Earthquakes in 3 sequences at Parkfield, California are recorded by multiple borehole stations and have abundant smaller earthquakes to use as EGFs (Abercrombie, 2014). The earthquakes in the largest magnitude cluster (M~2.1) exhibit clear temporal variation of stress drop. Independent studies obtained a similar pattern implying that it is resolvable for these well-recorded, simple sources. The borehole data reveal a similar temporal pattern for another sequence, not resolvable in an earlier study using surface recordings. The earthquakes in the third sequence have complex sources; corner frequency measurements for this sequence are highly variable and poorly resolved. We use the earthquakes in the first cluster to quantify the uncertainties likely to arise in less optimal settings. The limited signal bandwidth and the quality of the EGF assumption are major sources of error. Averaging across multiple stations improves the resolution, as does using multiple good EGFs (Abercrombie, 2015). We adapt the approach to apply to larger data sets. We focus on New Zealand, with the aim of resolving stress drop variability in a variety of tectonic settings. We investigate stacking over stations and multiple EGFs, and compare earthquakes (M~3-6) from both the overlying and the subducting plates.

  9. Statistical validation of earthquake related observations (United States)

    Kossobokov, V. G.


    optional "antipodal strategy", one can make the predictions efficient, so that the wins will systematically outscore the losses. Sounds easy, however, many precursor phenomena are lacking info on a rigorous control and, in many cases, even the necessary precondition of any scientific study, i.e., an unambiguous definition of "precursor/signal". On the other hand, understanding the complexity of seismic process along with its non-stationary hierarchically organized behaviors, has led already to reproducible intermediate-term middle-range earthquake prediction technique that has passed control test in forward real-time applications during at least the last two decades. In particular, place and time of each of the mega earthquakes of 27 February 2010 in Chile and 11 March 2011 in Japan were recognized as in state of increased probability of such events in advance their occurrences in the ongoing since 1992 Global Test of the algorithms M8 and MSc. These evidences, in conjunction with a retrospective analysis of seismic activity preceding 26 December 2004 in the Indian Ocean and other mega earthquakes of the 20th century, give grounds for assuming that the algorithms of validated effectiveness in magnitude ranges M7.5+ and M8.0+ are applicable to predict the mega-earthquakes as well.

  10. A Multi-parametric Climatological Approach to Study the 2016 Amatrice-Norcia (Central Italy) Earthquake Preparatory Phase (United States)

    Piscini, Alessandro; De Santis, Angelo; Marchetti, Dedalo; Cianchini, Gianfranco


    Based on observations prior to earthquakes, recent theoretical considerations suggest that some geophysical quantities reveal abnormal changes that anticipate moderate and strong earthquakes, within a defined spatial area (the so-called Dobrovolsky area) according to a lithosphere-atmosphere-ionosphere coupling model. One of the possible pre-earthquake effects could be the appearance of some climatological anomalies in the epicentral region, weeks/months before the major earthquakes. In this paper, the period of 2 months preceding the Amatrice-Norcia (Central Italy) earthquake sequence, that started on 24 August 2016 with an M6 earthquake and a few months later produced other two major shocks (i.e. an M5.9 on 26 October and then an M6.5 on 30 October), was analyzed in terms of skin temperature, total column water vapour and total column of ozone, compared with the past 37-year trend. The novelty of the method stands in the way the complete time series is reduced, where also the possible effect of global warming is properly removed. The simultaneous analysis showed the presence of persistent contemporary anomalies in all of the analysed parameters. To validate the technique, a confutation/confirmation analysis was undertaken where these parameters were successfully analyzed in the same months but considering a seismically "calm" year, when significant seismicity was not present. We also extended the analysis to all available years to construct a confusion matrix comparing the occurrence of climatological data anomalies with real seismicity. This work confirms the potentiality of multi parameters in anticipating the occurrence of large earthquakes in Central Italy, thus reinforcing the idea of considering such behaviour an effective tool for an integrated system of future earthquake prediction.

  11. From earthquake intensities to earthquake sources: extending the contribution of historical seismology to seismotectonic studies

    Directory of Open Access Journals (Sweden)

    G. Valensise


    Full Text Available The epicentral locations and magnitudes of the events reported in the Catalogue of Strong Italian Earthquakes are obtained from intensity data through a standardized and established algorithm. However, we contend that the dense and homogeneously collected data sets presented in this catalogue can also be used to assess the location, physical dimensions and orientation of the earthquake source on purely historical grounds. The method we describe is of special value for older earthquakes and for all events that fall in areas where the understanding of faulting and tectonics is limited. At the end of the calculations the seismic source is represented as an oriented "rectangle", the length and width of which are obtained from moment magnitude through empirical relationships. This rectangle is meant to represent the actual surface projection of the seismogenic fault or, at least, the projection of the portion of the Earth crust where a given seismic source is likely to be located. Sources derived through this procedure can then be juxtaposed to sources derived from instrumental and geological data for constructing fault segmentation and earthquake recurrence models and for highlighting linear gaps in the global seismic release. To test the method we applied it systematically to all M > 5.5 earthquakes that occurred in the Central and Southern Apennines in the past four centuries. The results are encouraging and compare well with existing instrumental, direct geological and geodynamic evidence. The method is quite stable for different choices of the algorithm parameters and provides elongation directions which in most cases can be shown to be statistically significant. The resulting pattern of source locations and orientations is homogeneous, showing a consistent Apennines-parallel trend that agrees well with the NE-SW tectonic extension style of the central and southern portions of the Italian peninsula.

  12. Determination of Design Basis Earthquake ground motion

    Energy Technology Data Exchange (ETDEWEB)

    Kato, Muneaki [Japan Atomic Power Co., Tokyo (Japan)


    This paper describes principle of determining of Design Basis Earthquake following the Examination Guide, some examples on actual sites including earthquake sources to be considered, earthquake response spectrum and simulated seismic waves. In sppendix of this paper, furthermore, seismic safety review for N.P.P designed before publication of the Examination Guide was summarized with Check Basis Earthquake. (J.P.N.)

  13. Earthquakes: Risk, Monitoring, Notification, and Research (United States)


    far away as Bangladesh , Taiwan, Thailand, and Vietnam. Several large aftershocks have occurred since the main seismic event. The May 12 earthquake...motion of tectonic plates; ! Earthquake geology and paleoseismology: studies of the history, effects, and mechanics of earthquakes; ! Earthquake hazards

  14. The 11 April 2012 east Indian Ocean earthquake triggered large aftershocks worldwide (United States)

    Pollitz, Fred F.; Stein, Ross S.; Sevilgen, Volkan; Burgmann, Roland


    Large earthquakes trigger very small earthquakes globally during passage of the seismic waves and during the following several hours to days1, 2, 3, 4, 5, 6, 7, 8, 9, 10, but so far remote aftershocks of moment magnitude M≥5.5 have not been identified11, with the lone exception of an M=6.9 quake remotely triggered by the surface waves from an M=6.6 quake 4,800 kilometres away12. The 2012 east Indian Ocean earthquake that had a moment magnitude of 8.6 is the largest strike-slip event ever recorded. Here we show that the rate of occurrence of remote M≥5.5 earthquakes (>1,500 kilometres from the epicentre) increased nearly fivefold for six days after the 2012 event, and extended in magnitude to M≥7. These global aftershocks were located along the four lobes of Love-wave radiation; all struck where the dynamic shear strain is calculated to exceed 10-7 for at least 100 seconds during dynamic-wave passage. The other M≥8.5 mainshocks during the past decade are thrusts; after these events, the global rate of occurrence of remote M≥5.5 events increased by about one-third the rate following the 2012 shock and lasted for only two days, a weaker but possibly real increase. We suggest that the unprecedented delayed triggering power of the 2012 earthquake may have arisen because of its strike-slip source geometry or because the event struck at a time of an unusually low global earthquake rate, perhaps increasing the number of nucleation sites that were very close to failure.

  15. Sun-earth environment study to understand earthquake prediction (United States)

    Mukherjee, S.


    Earthquake prediction is possible by looking into the location of active sunspots before it harbours energy towards earth. Earth is a restless planet the restlessness turns deadly occasionally. Of all natural hazards, earthquakes are the most feared. For centuries scientists working in seismically active regions have noted premonitory signals. Changes in thermosphere, Ionosphere, atmosphere and hydrosphere are noted before the changes in geosphere. The historical records talk of changes of the water level in wells, of strange weather, of ground-hugging fog, of unusual behaviour of animals (due to change in magnetic field of the earth) that seem to feel the approach of a major earthquake. With the advent of modern science and technology the understanding of these pre-earthquake signals has become stronger enough to develop a methodology of earthquake prediction. A correlation of earth directed coronal mass ejection (CME) from the active sunspots has been possible to develop as a precursor of the earthquake. Occasional local magnetic field and planetary indices (Kp values) changes in the lower atmosphere that is accompanied by the formation of haze and a reduction of moisture in the air. Large patches, often tens to hundreds of thousands of square kilometres in size, seen in night-time infrared satellite images where the land surface temperature seems to fluctuate rapidly. Perturbations in the ionosphere at 90 - 120 km altitude have been observed before the occurrence of earthquakes. These changes affect the transmission of radio waves and a radio black out has been observed due to CME. Another heliophysical parameter Electron flux (Eflux) has been monitored before the occurrence of the earthquakes. More than hundreds of case studies show that before the occurrence of the earthquakes the atmospheric temperature increases and suddenly drops before the occurrence of the earthquakes. These changes are being monitored by using Sun Observatory Heliospheric observatory

  16. 1964 Great Alaska Earthquake: a photographic tour of Anchorage, Alaska (United States)

    Thoms, Evan E.; Haeussler, Peter J.; Anderson, Rebecca D.; McGimsey, Robert G.


    , and small-scale maps, as well as links to slideshows of additional photographs and Google Street View™ scenes. Buildings in Anchorage that were severely damaged, sites of major landslides, and locations of post-earthquake engineering responses are highlighted. The web map can be used online as a virtual tour or in a physical self-guided tour using a web-enabled Global Positioning System (GPS) device. This publication serves the purpose of committing most of the content of the web map to a single distributable document. As such, some of the content differs from the online version.

  17. The 2012 MW5.6 earthquake in the vicinity of the city of Sofia (United States)

    Simeonova, Stela; Solakov, Dimcho; Aleksandrova, Irena; Dimitrova, Liliya; Popova, Iliana; Raykova, Plamena


    The territory of Bulgaria represents a typical example of high seismic risk area in the eastern part of the Balkan Peninsula. The neotectonic movements on the Balkan Peninsula were controlled by extensional collapse of the Late Alpin orogen, and were influenced by extension behind the Aegean arc and by the complicated vertical and horizontal movements in the Pannonian region. The city of Sofia is the capital of Bulgaria. It is situated in the centre of the Sofia seismic zone that is the most populated (more than 1.2 mil. inhabitants), industrial and cultural region of Bulgaria that faces considerable earthquake risk. Seismicity in the zone is related mainly to the marginal neotectonic faults of Sofia graben. The available historical documents prove the occurrence of destructive earthquakes during the 15th-18th centuries in the Sofia zone. In 19th century the city of Sofia has experienced two strong earthquakes: the 1818 earthquake with epicentral intensity I0=8-9 MSK and the 1858 earthquake with I0=IX-X MSK64. The 1858 earthquake caused heavy destruction in the town of Sofia and the appearance of thermal springs in the western part of the town. After a quiescence of about 50 years a strong event with M=6.5 occurred in 1905 near the western marginal part of the Sofia zone. 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 earthquake caused a lot of damages in the town and changed the capacity of the thermal mineral springs in Sofia and the surrounding villages. The earthquake was felt in an area of 50000 km2 and followed by aftershocks, which lasted more than one year. Almost a century later (95 years) an earthquake of moment magnitude 5.6 hit Sofia seismic zone, on May 22nd, 2012, at 25 km south west of the city of Sofia. This shallow earthquake was largely felt in the region and up to Greece, FYROM, Serbia and Romania. No severe injuries have been reported so far, though

  18. Hanford wells

    Energy Technology Data Exchange (ETDEWEB)

    McGhan, V.L.


    The Site Characterization and Assessment Section of the Geosciences Department at Pacific Northwest Laboratory (PNL) has compiled a list of wells located on or near the Hanford Site. Information has been updated on wells existing from the days before construction of the Hanford Works to the present. This work was funded by the US Department of Energy (DOE). The list of wells will be used by DOE contractors who need condensed, tabular information on well location, construction, and completion dates. This report does not include data on lithologic logs and ground-water contamination. Moreover, the completeness of this list is limited because of new well construction and existing well modifications, which are continually under way. Despite these limitations, this list represents the most complete description possible of data pertaining to wells on or adjacent to the Hanford Site. 7 refs., 1 fig., 2 tabs.

  19. <> earthquakes: a growing contribution to the Catalogue of Strong Italian Earthquakes

    Directory of Open Access Journals (Sweden)

    E. Guidoboni


    Full Text Available The particular structure of the research into historical seismology found in this catalogue has allowed a lot of information about unknown seismic events to be traced. This new contribution to seismologic knowledge mainly consists in: i the retrieval and organisation within a coherent framework of documentary evidence of earthquakes that took place between the Middle Ages and the sixteenth century; ii the improved knowledge of seismic events, even destructive events, which in the past had been "obscured" by large earthquakes; iii the identification of earthquakes in "silent" seismic areas. The complex elements to be taken into account when dealing with unknown seismic events have been outlined; much "new" information often falls into one of the following categories: simple chronological errors relative to other well-known events; descriptions of other natural phenomena, though defined in texts as "earthquakes" (landslides, hurricanes, tornadoes, etc.; unknown tremors belonging to known seismic periods; tremors that may be connected with events which have been catalogued under incorrect dates and with very approximate estimates of location and intensity. This proves that this was not a real seismic "silence" but a research vacuum.

  20. Operational Earthquake Forecasting and Earthquake Early Warning: The Challenges of Introducing Scientific Innovations for Public Safety (United States)

    Goltz, J. D.


    Although variants of both earthquake early warning and short-term operational earthquake forecasting systems have been implemented or are now being implemented in some regions and nations, they have been slow to gain acceptance within the disciplines that produced them as well as among those for whom they were intended to assist. To accelerate the development and implementation of these technologies will require the cooperation and collaboration of multiple disciplines, some inside and others outside of academia. Seismologists, social scientists, emergency managers, elected officials and key opinion leaders from the media and public must be the participants in this process. Representatives of these groups come from both inside and outside of academia and represent very different organizational cultures, backgrounds and expectations for these systems, sometimes leading to serious disagreements and impediments to further development and implementation. This presentation will focus on examples of the emergence of earthquake early warning and operational earthquake forecasting systems in California, Japan and other regions and document the challenges confronted in the ongoing effort to improve seismic safety.

  1. Earthquakes Induced by Hydraulic Fracturing in Poland Township, Ohio (United States)

    Skoumal, R.; Brudzinski, M. R.; Currie, B. S.


    Felt seismicity induced by hydraulic fracturing is very rare with only a handful of reported cases worldwide. Using an optimized multi-station cross-correlation template matching routine, 77 earthquakes were identified in Poland Township, Mahoning County, Ohio that were closely related spatially and temporally to active hydraulic fracturing operations. We identified earthquakes as small as M ~1 up to M 3, one of the largest earthquakes induced by hydraulic fracturing in the United States. These events all occurred 4-12 March 2014 and the rate decayed once the Ohio Department of Natural Resources issued a shutdown of hydraulic fracturing at a nearby well on 10 March. Using a locally derived velocity model and double difference relocation, the earthquake epicenters occurred during six stimulation stages along two horizontal well legs that were located ~0.8 km away. Nearly 100 stages in nearby wells at greater distances from the earthquake source region did not coincide with detected seismicity. During the sequence, hypocenters migrated ~600 m along an azimuth of 083 degrees defining a vertically oriented plane of seismicity close to the top of the Precambrian basement. The focal mechanism determined for the M 3 event had a vertically oriented left-lateral fault plane consistent with the earthquake distribution and the regional stress field. The focal mechanism, orientation, and depth of hypocenters were similar to that of the 2011 Youngstown earthquake sequence that occurred ~20 km away, but was correlated with wastewater injection instead of hydraulic fracturing. Considering the relatively large magnitude of these events and the b-value of 0.85, it appears the hydraulic fracturing induced slip along a pre-existing fault/fracture zone optimally oriented in the regional stress field.

  2. Assessment of earthquake-induced landslides hazard in El Salvador after the 2001 earthquakes using macroseismic analysis (United States)

    Esposito, Eliana; Violante, Crescenzo; Giunta, Giuseppe; Ángel Hernández, Miguel


    Two strong earthquakes and a number of smaller aftershocks struck El Salvador in the year 2001. The January 13 2001 earthquake, Mw 7.7, occurred along the Cocos plate, 40 km off El Salvador southern coast. It resulted in about 1300 deaths and widespread damage, mainly due to massive landsliding. Two of the largest earthquake-induced landslides, Las Barioleras and Las Colinas (about 2x105 m3) produced major damage to buildings and infrastructures and 500 fatalities. A neighborhood in Santa Tecla, west of San Salvador, was destroyed. The February 13 2001 earthquake, Mw 6.5, occurred 40 km east-southeast of San Salvador. This earthquake caused over 300 fatalities and triggered several landslides over an area of 2,500 km2 mostly in poorly consolidated volcaniclastic deposits. The La Leona landslide (5-7x105 m3) caused 12 fatalities and extensive damage to the Panamerican Highway. Two very large landslides of 1.5 km3 and 12 km3 produced hazardous barrier lakes at Rio El Desague and Rio Jiboa, respectively. More than 16.000 landslides occurred throughout the country after both quakes; most of them occurred in pyroclastic deposits, with a volume less than 1x103m3. The present work aims to define the relationship between the above described earthquake intensity, size and areal distribution of induced landslides, as well as to refine the earthquake intensity in sparsely populated zones by using landslide effects. Landslides triggered by the 2001 seismic sequences provided useful indication for a realistic seismic hazard assessment, providing a basis for understanding, evaluating, and mapping the hazard and risk associated with earthquake-induced landslides.

  3. An application of earthquake prediction algorithm M8 in eastern Anatolia at the approach of the 2011 Van earthquake

    Indian Academy of Sciences (India)

    Masoud Mojarab; Vladimir Kossobokov; Hossein Memarian; Mehdi Zare


    On 23rd October 2011, an M7.3 earthquake near the Turkish city of Van, killed more than 600 people, injured over 4000, and left about 60,000 homeless. It demolished hundreds of buildings and caused great damages to thousand others in Van, Ercis, Muradiye, and Çaldıran. The earthquake’s epicenter is located about 70 km from a preceding M7.3 earthquake that occurred in November 1976 and destroyed several villages near the Turkey–Iran border and killed thousands of people. This study, by means of retrospective application of the M8 algorithm, checks to see if the 2011 Van earthquake could have been predicted. The algorithm is based on pattern recognition of Times of Increased Probability (TIP) of a target earthquake from the transient seismic sequence at lower magnitude ranges in a Circle of Investigation (CI). Specifically, we applied a modified M8 algorithm adjusted to a rather low level of earthquake detection in the region following three different approaches to determine seismic transients. In the first approach, CI centers are distributed on intersections of morphostructural lineaments recognized as prone to magnitude 7+ earthquakes. In the second approach, centers of CIs are distributed on local extremes of the seismic density distribution, and in the third approach, CI centers were distributed uniformly on the nodes of a 1°×1° grid. According to the results of the M8 algorithm application, the 2011 Van earthquake could have been predicted in any of the three approaches. We noted that it is possible to consider the intersection of TIPs instead of their union to improve the certainty of the prediction results. Our study confirms the applicability of a modified version of the M8 algorithm for predicting earthquakes at the Iranian–Turkish plateau, as well as for mitigation of damages in seismic events in which pattern recognition algorithms may play an important role.

  4. The physics of an earthquake (United States)

    McCloskey, John


    The Sumatra-Andaman earthquake of 26 December 2004 (Boxing Day 2004) and its tsunami will endure in our memories as one of the worst natural disasters of our time. For geophysicists, the scale of the devastation and the likelihood of another equally destructive earthquake set out a series of challenges of how we might use science not only to understand the earthquake and its aftermath but also to help in planning for future earthquakes in the region. In this article a brief account of these efforts is presented. Earthquake prediction is probably impossible, but earth scientists are now able to identify particularly dangerous places for future events by developing an understanding of the physics of stress interaction. Having identified such a dangerous area, a series of numerical Monte Carlo simulations is described which allow us to get an idea of what the most likely consequences of a future earthquake are by modelling the tsunami generated by lots of possible, individually unpredictable, future events. As this article was being written, another earthquake occurred in the region, which had many expected characteristics but was enigmatic in other ways. This has spawned a series of further theories which will contribute to our understanding of this extremely complex problem.

  5. Ionospheric phenomena before strong earthquakes

    Directory of Open Access Journals (Sweden)

    A. S. Silina


    Full Text Available A statistical analysis of several ionospheric parameters before earthquakes with magnitude M > 5.5 located less than 500 km from an ionospheric vertical sounding station is performed. Ionospheric effects preceding "deep" (depth h > 33 km and "crust" (h 33 km earthquakes were analysed separately. Data of nighttime measurements of the critical frequencies foF2 and foEs, the frequency fbEs and Es-spread at the middle latitude station Dushanbe were used. The frequencies foF2 and fbEs are proportional to the square root of the ionization density at heights of 300 km and 100 km, respectively. It is shown that two days before the earthquakes the values of foF2 averaged over the morning hours (00:00 LT–06:00 LT and of fbEs averaged over the nighttime hours (18:00 LT–06:00 LT decrease; the effect is stronger for the "deep" earthquakes. Analysing the coefficient of semitransparency which characterizes the degree of small-scale turbulence, it was shown that this value increases 1–4 days before "crust" earthquakes, and it does not change before "deep" earthquakes. Studying Es-spread which manifests itself as diffuse Es track on ionograms and characterizes the degree of large-scale turbulence, it was found that the number of Es-spread observations increases 1–3 days before the earthquakes; for "deep" earthquakes the effect is more intensive. Thus it may be concluded that different mechanisms of energy transfer from the region of earthquake preparation to the ionosphere occur for "deep" and "crust" events.

  6. 重组人CREG蛋白与溶酶体组织蛋白酶和M6P/IGFⅡR的相互作用%Interactions between the recombinant human CREG protein and cathepsins and M6P/IGFIIR

    Institute of Scientific and Technical Information of China (English)

    孙鸣宇; 闫承慧; 田孝祥; 李洋; 韩雅玲


    BACKGROUND:It has been found that cel ular repressor of E1A-stimulated genes (CREG) is a lysosomal protein binding directly to the mannose-6-phosphate (M6P)/insulin-like growth factor II receptor (IGFIIR) and depends on the interaction with M6P receptors for efficient delivery to lysosomes OBJECTIVE:To study the interactions between the exogenous CREG protein and cathepsins and M6P/IGFIIR and to confirm the effect of CREG protein on expression and distribution of M6P/IGFIIR. METHODS:Double-stained immunofluorescence and coimmunoprecipitation were applied to observe the interactions between the exogenous CREG protein and cathepsin B, cathepsin L and M6P/IGFIIR. Using gain-of-function and loss-of-function approaches, the effect of CREG on expression and distribution of M6P/IGFIIR were studied by western blot assay and immunofluorescence staining. RESULTS AND CONCLUSION:Double-stained immunofluorescence and coimmunoprecipitation analyses confirmed the direct interactions between the exogenous CREG protein and cathepsin B, cathepsin L and M6P/IGFIIR. It was verified that CREG plays a critical role not in the expression but in the distribution of M6P/IGFIIR using gain-of-function and loss-of-function approaches. These findings provide evidence that exogenous CREG protein is located in lysosomes and has interactions with cathepsins and M6P/IGFIIR, also CREG plays a critical role in the distribution of M6P/IGFIIR.%背景:以往研究证实,CREG是一种与M6P/IGFⅡR直接结合的溶酶体蛋白,并依赖于与M6P受体的相互作用有效转运至溶酶体。  目的:分析外源性CREG蛋白与溶酶体组织蛋白酶和M6P/IGFⅡR的相互作用关系及其对M6P/IGFⅡR表达变化及细胞内定位的影响。  方法:应用细胞免疫荧光双染和免疫共沉淀方法,观察外源性 CREG 蛋白与溶酶体组织蛋白酶和 M6P/IGFⅡR的相互作用关系,并应用gain-of-function和loss-of-function模型,通过Western blot和细胞

  7. Tien Shan Geohazards Database: Earthquakes and landslides (United States)

    Havenith, H. B.; Strom, A.; Torgoev, I.; Torgoev, A.; Lamair, L.; Ischuk, A.; Abdrakhmatov, K.


    In this paper we present new and review already existing landslide and earthquake data for a large part of the Tien Shan, Central Asia. For the same area, only partial databases for sub-regions have been presented previously. They were compiled and new data were added to fill the gaps between the databases. Major new inputs are products of the Central Asia Seismic Risk Initiative (CASRI): a tentative digital map of active faults (even with indication of characteristic or possible maximum magnitude) and the earthquake catalogue of Central Asia until 2009 that was now updated with USGS data (to May 2014). The new compiled landslide inventory contains existing records of 1600 previously mapped mass movements and more than 1800 new landslide data. Considering presently available seismo-tectonic and landslide data, a target region of 1200 km (E-W) by 600 km (N-S) was defined for the production of more or less continuous geohazards information. This target region includes the entire Kyrgyz Tien Shan, the South-Western Tien Shan in Tajikistan, the Fergana Basin (Kyrgyzstan, Tajikistan and Uzbekistan) as well as the Western part in Uzbekistan, the North-Easternmost part in Kazakhstan and a small part of the Eastern Chinese Tien Shan (for the zones outside Kyrgyzstan and Tajikistan, only limited information was available and compiled). On the basis of the new landslide inventory and the updated earthquake catalogue, the link between landslide and earthquake activity is analysed. First, size-frequency relationships are studied for both types of geohazards, in terms of Gutenberg-Richter Law for the earthquakes and in terms of probability density function for the landslides. For several regions and major earthquake events, case histories are presented to outline further the close connection between earthquake and landslide hazards in the Tien Shan. From this study, we concluded first that a major hazard component is still now insufficiently known for both types of geohazards

  8. Earthquakes and depleted gas reservoirs: which comes first?

    Directory of Open Access Journals (Sweden)

    M. Mucciarelli


    Full Text Available While scientists are paying increasing attention to the seismicity potentially induced by hydrocarbon exploitation, little is known about the reverse problem, i.e. the impact of active faulting and earthquakes on hydrocarbon reservoirs. The recent 2012 earthquakes in Emilia, Italy, raised concerns among the public for being possibly human-induced, but also shed light on the possible use of gas wells as a marker of the seismogenic potential of an active fold-and-thrust belt. Based on the analysis of over 400 borehole datasets from wells drilled along the Ferrara-Romagna Arc, a large oil and gas reserve in the southeastern Po Plain, we found that the 2012 earthquakes occurred within a cluster of sterile wells surrounded by productive ones. Since the geology of the productive and sterile areas is quite similar, we suggest that past earthquakes caused the loss of all natural gas from the potential reservoirs lying above their causative faults. Our findings have two important practical implications: (1 they may allow major seismogenic zones to be identified in areas of sparse seismicity, and (2 suggest that gas should be stored in exploited reservoirs rather than in sterile hydrocarbon traps or aquifers as this is likely to reduce the hazard of triggering significant earthquakes.

  9. Psychological Morbidity in Children 18 Months after Kashmir Earthquake of 2005 (United States)

    Ayub, Muhammad; Poongan, Ishwari; Masood, Khadija; Gul, Huma; Ali, Mahwish; Farrukh, Ammara; Shaheen, Aisha; Chaudhry, Haroon Rasheed; Naeem, Farooq


    A severe earthquake occurred in Kashmir in 2005. The epicentre was close to Muzzafarabad. We collected data on over 1,100 children 18 months after the earthquake to look at symptoms of PTSD and behavioural and emotional problems using well established questionnaires. We found that 64.8% of children had significant symptoms of PTSD. Girls were more…

  10. Psychological Morbidity in Children 18 Months after Kashmir Earthquake of 2005 (United States)

    Ayub, Muhammad; Poongan, Ishwari; Masood, Khadija; Gul, Huma; Ali, Mahwish; Farrukh, Ammara; Shaheen, Aisha; Chaudhry, Haroon Rasheed; Naeem, Farooq


    A severe earthquake occurred in Kashmir in 2005. The epicentre was close to Muzzafarabad. We collected data on over 1,100 children 18 months after the earthquake to look at symptoms of PTSD and behavioural and emotional problems using well established questionnaires. We found that 64.8% of children had significant symptoms of PTSD. Girls were more…

  11. OPERATIONAL EARTHQUAKE FORECASTING. State of Knowledge and Guidelines for Utilization

    Directory of Open Access Journals (Sweden)

    Koshun Yamaoka


    , which may also be useful in other countries. The public should be provided with open sources of information about the short-term probabilities of future earthquakes that are authoritative, scientific, consistent, and timely. Advisories should be based on operationally qualified, regularly updated seismicity forecasting systems that have been rigorously reviewed and updated by experts in the creation, delivery, and utility of earthquake information. The quality of all operational models should be evaluated for reliability and skill by retrospective testing, and they should be under continuous prospective testing against established long-term forecasts and alternative time-dependent models. Alert procedures should be standardized to facilitate decisions at different levels of government and among the public. Earthquake probability thresholds should be established to guide alert levels based on objective analysis of costs and benefits, as well as the less tangible aspects of value-of-information, such as gains in psychological preparedness and resilience. The principles of effective public communication established by social science research should be applied to the delivery of seismic hazard information.

  12. The threat of silent earthquakes (United States)

    Cervelli, Peter


    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.

  13. Earthquakes: Thinking about the unpredictable (United States)

    Geller, Robert J.

    The possibility of predicting earthquakes has been investigated by professionals and amateurs, seismologists and nonseismologists, for over 100 years. More than once, hopes of a workable earthquake prediction scheme have been raised only to be dashed. Such schemes—on some occasions accompanied by claims of an established track record—continue to be proposed, not only by Earth scientists, but also by workers in other fields. The assessment of these claims is not just a scientific or technical question. Public administrators and policy makers must make decisions regarding appropriate action in response to claims that some scheme has a predictive capability, or to specific predictions of imminent earthquakes.

  14. Multidimensional scaling visualization of earthquake phenomena (United States)

    Lopes, António M.; Machado, J. A. Tenreiro; Pinto, C. M. A.; Galhano, A. M. S. F.


    Earthquakes are associated with negative events, such as large number of casualties, destruction of buildings and infrastructures, or emergence of tsunamis. In this paper, we apply the Multidimensional Scaling (MDS) analysis to earthquake data. MDS is a set of techniques that produce spatial or geometric representations of complex objects, such that, objects perceived to be similar/distinct in some sense are placed nearby/distant on the MDS maps. The interpretation of the charts is based on the resulting clusters since MDS produces a different locus for each similarity measure. In this study, over three million seismic occurrences, covering the period from January 1, 1904 up to March 14, 2012 are analyzed. The events, characterized by their magnitude and spatiotemporal distributions, are divided into groups, either according to the Flinn-Engdahl seismic regions of Earth or using a rectangular grid based in latitude and longitude coordinates. Space-time and Space-frequency correlation indices are proposed to quantify the similarities among events. MDS has the advantage of avoiding sensitivity to the non-uniform spatial distribution of seismic data, resulting from poorly instrumented areas, and is well suited for accessing dynamics of complex systems. MDS maps are proven as an intuitive and useful visual representation of the complex relationships that are present among seismic events, which may not be perceived on traditional geographic maps. Therefore, MDS constitutes a valid alternative to classic visualization tools, for understanding the global behavior of earthquakes.

  15. Management of limb fractures in a teaching hospital: comparison between Wenchuan and Yushu earthquakes

    Institute of Scientific and Technical Information of China (English)

    MIN Li; TU Chong-qi; LIU Lei; ZHANG Wen-li; YI Min; SONG Yue-ming; HUANG Fu-guo; YANG Tian-fu; PEI Fu-xing


    Objective:To comparatively analyze the medical records of patients with limb fractures as well as rescue strategy in Wenchuan and Yushu earthquakes so as to provide references for post-earthquake rescue.Methods:We retrospectively investigated 944 patients sustaining limb fractures,including 891 in Wenchuan earthquake and 53 in Yushu earthquake,who were admitted to West China Hospital (WCH) of Sichuan University.Results:In Wenchuan earthquake,WCH met its three peaks of limb fracture patients influx,on post-earthquake day (PED) 2,8 and 14 respectively.Between PED 3-14,585 patients were transferred from WCH to other hospitals outside the Sichuan Province.In Yushu earthquake,the maximum influx of limb fracture patients happened on PED 3,and no one was shifted to other hospitals.Both in Wenchuan and Yushu earthquakes,most limb fractures were caused by blunt strike and crash/burying.In Wenchuan earthquake,there were 396 (396/942,42.0%) open limb fractures,including 28 Gustilo Ⅰ,201 Gustilo Ⅱ and 167 Gustilo Ⅲ injuries.But in Yushu earthquake,the incidence of open limb fracture was much lower (6/61,9.8%).The percent of patients with acute complications in Wenchuan earthquake (167/891,18.7%) was much higher than that in Yushu earthquake (5/53,3.8%).In Wenchuan earthquake rescue,1 018 surgeries were done,composed of debridement in 376,internal fixation in 283,external fixation in 119,and vacuum sealing drainage in 117,etc.While among the 64 surgeries in Yushu earthquake rescue,the internal fixation for limb fracture was mostly adopted.All patients received proper treatment and survived except one who died due to multiple organs failure in Wenchuan earthquake.Conclusion:Provision of suitable and sufficient medical care in a catastrophe can only be achieved by construction of sophisticated national disaster medical system,prediction of the injury types and number of injuries,and confirmation of participating hospitals' exact role.Based on the valuable rescue

  16. Management of limb fractures in a teaching hospital: comparison between Wenchuan and Yushu earthquakes. (United States)

    Min, Li; Tu, Chong-qi; Liu, Lei; Zhang, Wen-li; Yi, Min; Song, Yue-ming; Huang, Fu-guo; Yang, Tian-fu; Pei, Fu-xing


    To comparatively analyze the medical records of patients with limb fractures as well as rescue strategy in Wenchuan and Yushu earthquakes so as to provide references for post-earthquake rescue. We retrospectively investigated 944 patients sustaining limb fractures, including 891 in Wenchuan earthquake and 53 in Yushu earthquake, who were admitted to West China Hospital (WCH) of Sichuan University. In Wenchuan earthquake, WCH met its three peaks of limb fracture patients influx, on post-earthquake day (PED) 2, 8 and 14 respectively. Between PED 3-14, 585 patients were transferred from WCH to other hospitals outside the Sichuan Province. In Yushu earthquake, the maximum influx of limb fracture patients happened on PED 3, and no one was shifted to other hospitals. Both in Wenchuan and Yushu earthquakes, most limb fractures were caused by blunt strike and crush/burying. In Wenchuan earthquake, there were 396 (396/942, 42.0%) open limb fractures, including 28 Gustilo I, 201 Gustilo II and 167 Gustilo III injuries. But in Yushu earthquake, the incidence of open limb fracture was much lower (6/61, 9.8%). The percent of patients with acute complications in Wenchuan earthquake (167/891, 18.7%) was much higher than that in Yushu earthquake (5/53, 3.8%). In Wenchuan earthquake rescue, 1 018 surgeries were done, composed of debridement in 376, internal fixation in 283, external fixation in 119, and vacuum sealing drainage in 117, etc. While among the 64 surgeries in Yushu earthquake rescue, the internal fixation for limb fracture was mostly adopted. All patients received proper treatment and survived except one who died due to multiple organs failure in Wenchuan earthquake. Provision of suitable and sufficient medical care in a catastrophe can only be achieved by construction of sophisticated national disaster medical system, prediction of the injury types and number of injuries, and confirmation of participating hospitals?exact role. Based on the valuable rescue experiences


    Directory of Open Access Journals (Sweden)

    Savaş TOPAL


    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.

  18. Constraints on the Size of the Smallest Triggering Earthquake from the ETAS Model, Baath's Law, and Observed Aftershock Sequences

    CERN Document Server

    Sornette, D


    The physics of earthquake triggering together with simple assumptions of self-similarity impose the existence of a minimum magnitude m0 below which earthquakes do not trigger other earthquakes. Noting that the magnitude md of completeness of seismic catalogs has no reason to be the same as the magnitude m0 of the smallest triggering earthquake, we use quantitative fits and maximum likelihood inversions of observed aftershock sequences as well as Baath's law, compare with ETAS model predictions and thereby constrain the value of m0. We show that the branching ratio $n$ (average number of triggered earthquake per earthquake also equal to the fraction of aftershocks in seismic catalogs) is the key parameter controlling the minimum triggering magnitude m0. Conversely, physical upper bounds for m0 derived from state- and velocity-weakening friction indicate that at least 60 to 70 percent of all earthquakes are aftershocks.

  19. Microearthquake detection at 2012 M4.9 Qiaojia earthquake source area , the north of the Xiaojiang Fault in Yunnan, China (United States)

    Li, Y.; Yang, H.; Zhou, S.; Yan, C.


    We perform a comprehensive analysis in Yunnan area based on continuous seismic data of 38 stations of Qiaojia Network in Xiaojiang Fault from 2012.3 to 2015.2. We use an effective method: Match and Locate (M&L, Zhang&Wen, 2015) to detect and locate microearthquakes to conduct our research. We first study dynamic triggering around the Xiaojiang Fault in Yunnan. The triggered earthquakes are identified as two impulsive seismic arrivals in 2Hz-highpass-filtered velocity seismograms during the passage of surface waves of large teleseismic earthquakes. We only find two earthquakes that may have triggered regional earthquakes through inspecting their spectrograms: Mexico Mw7.4 earthquake in 03/20/2012 and El Salvador Mw7.3 earthquake in 10/14/2014. To confirm the two earthquakes are triggered instead of coincidence, we use M&L to search if there are any repeating earthquakes. The result of the coefficients shows that it is a coincidence during the surface waves of El Salvador earthquake and whether 2012 Mexico have triggered earthquake is under discussion. We then visually inspect the 2-8Hz-bandpass-filterd velocity envelopes of these years to search for non-volcanic tremor. We haven't detected any signals similar to non-volcanic tremors yet. In the following months, we are going to study the 2012 M4.9 Qiaojia earthquake. It occurred only 30km west of the epicenter of the 2014 M6.5 Ludian earthquake. We use Match and Locate (M&L) technique to detect and relocate microearthquakes that occurred 2 days before and 3 days after the mainshock. Through this, we could obtain several times more events than listed in the catalogs provided by NEIC and reduce the magnitude of completeness Mc. We will also detect microearthquakes along Xiaojiang Fault using template earthquakes list