Facts learnt from the Hanshin-Awaji disaster and consideration on design basis earthquake

Energy Technology Data Exchange (ETDEWEB)

Shibata, Heki [Yokohama National Univ. (Japan). Faculty of Engineering

1997-03-01

This paper will deal with how to establish the concept of the design basis earthquake for critical industrial facilities such as nuclear power plants in consideration of disasters induced by the 1995 Hyogoken-Nanbu Earthquake (Southern Hyogo-prefecture Earthquake-1995), so-called Kobe earthquake. The author once discussed various DBEs at 7 WCEE. At that time, the author assumed that the strongest effective PGA would be 0.7 G, and compared to the values of accelerations to a structure obtained by various codes in Japan and other countries. The maximum PGA observed by an instrument at the Southern Hyogo-pref. Earthquake-1995 exceeded the previous assumption of the author, even though the evaluation results of the previous paper had been pessimistic. According to the experience of Kobe event, the author will point out the necessity of the third earthquake S{sub s} adding to S{sub 1} and S{sub 2}, previous DBEs. (author)

Analisi teorico-sperimentale di collegamenti dissipativi a parziale ripristino di resistenza in strutture intelaiate in acciaio

OpenAIRE

Latour, Massimo

2011-01-01

2009 - 2010 Before seismic events of Northridge (Los Angeles, 17 January 1994) and Hyogoken-Nanbu (Kobe, 17 January 1995) MRFs were supposed to be the most reliable seismic resistant systems due to the high number of dissipative zones that are able to develop Before these earthquakes, especially in United States, MRFs were realized, generally, by adopting fully welded connections, which, at the time, were retained to perform better compared to other joint typologies. In a...

Erection of the stiffening girder of the Akashi Kaikyo bridge; Akashi Kaikyo Ohashi hokoketa (sono 2) koji no genchi seko

Energy Technology Data Exchange (ETDEWEB)

Otsuki, M.; Inoue, M.; Ueno, Y.; Matsumura, T.; Oe, S. [Kawasaki Heavy Industries, Ltd., Kobe (Japan)

1998-12-20

The Akashi Kaikyo Bridge is 3,911m long with a center span of 1,991m, making it the longest suspension bridge in the world. Much careful attention has been given to the erection planning details in order to construct the bridge to withstand the harsh environmental conditions of that area. This report details the characteristics of the bridge stiffening girder and erection procedure, and the effects of the Hyogoken-Nanbu Earthquake. (author)

地震時の人体被災度計測手法の開発 : 胸部圧迫実験用ダミーの作製

OpenAIRE

宮野, 道雄; 生田, 英輔; 長嶋, 文雄; 田中, 裕; 梶原, 浩一; 奥野, 倫子; Michio, MIYANO; Eisuke, IKUTA; Fumio, NAGASHIMA; Hiroshi, TANAKA; Kouichi, KAJIWARA; Michiko, OKUNO; 大阪市立大学大学院生活科学研究科; 大阪市立大学大学院生活科学研究科; 首都大学東京大学院都市環境科学研究科

2008-01-01

The immediate victims of the 1995 Hyogo-ken Nanbu Earthquake included 5,502 dead and 41,527 wounded. The death rate among victims in collapsed buildings was purported to be as high as 90%. However, we have no way to examine how the victim got dead or wounded, except for autopsy and interview with the bereaved. We need knowledge in detail about what part of building or furniture caused casualty and how it was occurred. Therfore, we aimed to make a dummy to measure human body damage due to coll...

Effect of earthquake and faulting on the hydrological environment

Energy Technology Data Exchange (ETDEWEB)

Abe, Hironobu [Japan Nuclear Cycle Development Inst., Toki, Gifu (Japan). Tono Geoscience Center; Sakai, Ryutaro

1999-12-01

The effects of earthquakes and active faults on the geological environment have been studied at the Tono Geoscience Center. The Hyogoken-Nanbu earthquake (January 17, 1995; M7.2) in Kobe and Awaji island caused significant changes in hydrology, involving a large amount of groundwater discharge in low-lying land and drastic water-table lowering (during only about 2-4 months) in elevated land near the epicenter. Simulation of the groundwater behavior in the vicinity of the Nojima fault was analysed to evaluate permeability enhancements. Calculated values such as water level changes were matched in a time series with the hydrological observed data in order to optimize this simulation model. Results indicate that the increase of hydraulic conductivity (5 x 10{sup -3} cm/s in weathered granitic rocks) and 1 x 10{sup -5} cm/s in fresh granitic rocks would produce a lowering of the water level at EL 180 m, and increase of discharge at less than EL 100 m, within four months after the earthquake. The study also suggested that the change in the hydraulic conductivity in the Nojima fault could not depend on the change in geological hydrology. (author)

Development of a new modeling technique of 3D S-wave velocity structure for strong ground motion evaluation - Integration of various geophysical and geological data using joint inversion

International Nuclear Information System (INIS)

Sugimoto, Yoshihiro

2014-01-01

A restricted stripe-like zone suffered major damage due to the 1995 Hyogo-ken Nanbu earthquake, and ground motion of the south side of the Kashiwazaki NPP site was much greater than that of the north side in the 2007 Niigata-ken Chuetsu-oki earthquake. One reason for these phenomena is thought to be the focusing effect due to irregularly shaped sedimentary basins (e.g., basin-edge structure, fold structure, etc.) This indicates that precise evaluation of S-wave velocity structure is important. A calculation program that was developed to make S-wave velocity models using the joint inversion method was presented. This program unifies various geophysical and geological data and can make a complex structure model for evaluating strong ground motion with high precision. (author)

Estimation of site effects in Higashinada Ward, Kobe City using aftershock records of the 1995 Hyogo-Ken Nanbu Earthquake; Hyogoken nanbu jishin no yoshin kiroku wo mochiita Kobeshihigashinadaku no jiban zofuku tokusei no hyoka

Energy Technology Data Exchange (ETDEWEB)

Kurita, K.; Yamanaka, H.; Seo, K. [Tokyo Inst. of Tech. (Japan)

1998-07-30

Source spectra and site effects are separated using the aftershock records, and the characteristics of short period earthquake motion in Higashinada Ward, Kobe City including the area to the south of seismic intensity 7 area are investigated placing emphasis on how far the site effects can be explained by 1-D ground structure. The shape and amplitude of the site effect of KNN and KYC located outside the seismic intensity 7 area can be explained fairly well by 1-D multiple reflection theory of S wave. However, peaks near 3 to 4Hz of KNN and UOZ in seismic intensity 7 area can not be explained. This suggests that the site effects of seismic intensity 7 area obtained by the aftershock records might include 2-D effects of underground structure. Inversion is performed using site effects as the objective functions to determine S wave velocity structure and Qs in the sedimentary layer. S wave velocity structure shows no systematical difference from those of the past models. 22 refs., 13 figs., 2 tabs.

On seismic intensities of questionnaires for 1996 earthquake near Akita-Miyagi prefecture

Energy Technology Data Exchange (ETDEWEB)

Nogoshi, M; Sasaki, N [Akita University, Akita (Japan). College of Education; Nakamura, M [Nippon Geophysical Prospecting Co. Ltd., Tokyo (Japan)

1997-05-27

The earthquake occurred in 1996 near the border of Akita and Miyagi Prefectures was a seismic activity in mountainous area with low population density. However, since a necessity was felt to make a seismic intensity survey, a questionnaire investigation was carried out. The investigation placed a focus on the following points: (1) to learn seismic intensity distribution in the vicinity of the epicenter by using replies to the questionnaire and (2) to learn what evacuation activities the residents have taken to avoid disasters from the earthquake, which is an inland local earthquake occurred first since the Hyogoken-nanbu earthquake in 1995. Because the main shock has occurred in the Akita prefecture side, the shocks were concentrated at Akinomiya, Takamatsu, Sugawa and Koyasu areas where the intensities were 4.0 to 4.5 in most cases. The largest aftershocks were concentrated to the Miyagi prefecture side, with an intensity of 6.0 felt most, followed by 5.5. The questionnaire on evacuation actions revealed a result of about 37% of the reply saying, ``I have jumped out of my house before I knew what has happened`` and ``I remember nothing about what I did because I was acting totally instinctively``. The answers show how intense the experience was. This result indicates how to make the unconscious actions turned into conscious actions is an important issue in preventing disasters. 11 figs.

Geological structure of Osaka basin and characteristic distributions of structural damage caused by earthquake; Osaka bonchi kozo to shingai tokusei

Energy Technology Data Exchange (ETDEWEB)

Nakagawa, K; Shiono, K; Inoue, N; Senda, S [Osaka City University, Osaka (JP. Faculty of Science); Ryoki, K [Osaka Polytechnic Collage, Osaka (Japan); Shichi, R [Nagoya University, Nagoya (Japan). Faculty of Science

1996-05-01

The paper investigates relations between the damage caused by the Hyogo-ken Nanbu earthquake and the deep underground structures. A characteristic of the earthquake damage distribution is that the damage concentrated near faults. Most of the damages were seen on the side of faults` relatively falling rather than right above the faults and of their slightly slanting to the seaside. Distribution like this seems to be closely related to underground structures. Therefore, a distribution map of the depth of basement granite in Osaka sedimentary basin was drawn, referring to the data on basement rock depth obtained from the distribution map of gravity anomaly and the result of the survey using the air gun reflection method. Moreover, cubic underground structures were determined by 3-D gravity analysis. The result was concluded as follows: when observing the M7 zone of the low land, in particular, where the damage was great from an aspect of gravity anomaly, the basement rock below the zone declined near the cliff toward the sea, which indicates a great possibility of its being a fault. There is a high possibility that the zone suffered mostly from the damage caused by focusing by refraction and total reflection of seismic wave rays. 3 refs., 8 figs.

Nondestructive damage detection and evaluation technique for seismically damaged structures

Science.gov (United States)

Adachi, Yukio; Unjoh, Shigeki; Kondoh, Masuo; Ohsumi, Michio

1999-02-01

The development of quantitative damage detection and evaluation technique, and damage detection technique for invisible damages of structures are required according to the lessons from the 1995 Hyogo-ken Nanbu earthquake. In this study, two quantitative damage sensing techniques for highway bridge structures are proposed. One method is to measure the change of vibration characteristics of the bridge structure. According to the damage detection test for damaged bridge column by shaking table test, this method can successfully detect the vibration characteristic change caused by damage progress due to increment excitations. The other method is to use self-diagnosis intelligent materials. According to the reinforced concrete beam specimen test, the second method can detect the damage by rupture of intelligent sensors, such as optical fiber or carbon fiber reinforced plastic rod.

Interferometric SAR and land deformation. Analysis using the dislocation model; Interferometric SAR to chikaku hendo. Dislocation model wo mochiita kaiseki

Energy Technology Data Exchange (ETDEWEB)

Matsushima, J; Otaki, T; Tanaka, A; Miyazaki, Y [Geological Survey of Japan, Tsukuba (Japan)

1996-05-01

The diastrophism by the earthquake-induced dislocation is investigated by interferometry (INSAR) which represents the diastrophism by the interference fringes of equiphase difference lines. A joint research group at Geographical Survey Institute and National Space Development Agency showed the diastrophism in the vicinity of the ground surfaces before and after the Hyogoken Nanbu Earthquake by the INSAR interference images in 1995. This paper discusses the effects of observation in the vision line direction from the satellite and dislocation parameters on the interference images. The dislocation model uses a slanted rectangular model in a semi-infinite medium, to calculate static displacements and strain distributions at the ground surface, when dislocation changes. It is found that the INSAR interference images, detecting displacements in the vision line direction from the satellite, significantly change as the vision line direction changes, and that the actual displacement cannot be given by the images alone. This paper also shows sensitivity of the interference images to the dislocation parameters. 3 refs., 9 figs., 1 tab.

SOCIETAL IMPLICATIONS OF GREAT HANSHIN-AWAJI EARTHQUAKE DISASTER OF JANUARY 17,1995

OpenAIRE

Haruo, HAYASHI; Yoshiaki, KAWATA; Associate Professor, Research Center for Disaster Reduction Systems, Disaster Prevention Research Institute, Kyoto University; Professor, Research Center for Disaster Reduction Systems, Disaster Prevention Research Institute, Kyoto University

1995-01-01

A brief overview of what happened during the first month after the Hyogoken-nambu earthquake of January 17,1995 is given in terms both of the emergency responses initiated and the societal impact. For emergency responses, formal organization responses are discussed in reference to "Saigai taisaku kihon-ho (the Fundamental Disaster Management Law)" and "Saigai kyujyo-ho (the Disaster Relief Law)". Using the Kobe Fire Department as an example, search and rescue efforts as well as fire suppressi...

Societal implications of great Hanshin-awaji earthquake disaster of January 17, 1995

OpenAIRE

KAWATA, Yoshiaki; HAYASHI, Haruo

1995-01-01

A brief overview of what happened during the first month after the Hyogoken-nambu earthquake of January 17, 1995 is given in terms both of the emergency responses initiated and the societal impact. For emergency responses, formal organization responses are discussed in reference to "Saigai taisaku kihon-ho (the Fundamental Disaster Management Law)" and "Saigai kyujyo-ho (the Disaster Relief Law)". Using the Kobe Fire Department as an example, search and rescue efforts as well as fire suppress...

The January 17, 1994 Northridge Earthquake: Effects on selected industrial facilities and lifelines

Energy Technology Data Exchange (ETDEWEB)

Eli, M.W.; Sommer, S.C. [Lawrence Livermore National Lab., CA (United States); Roche, T.R.; Merz, K.L.

1995-02-01

Revision 0 of this report is being published in February 1995 to closely mark the one-year anniversary of the Northridge Earthquake. A September 1994 Draft version of the report was reviewed by DOE and NRC, and many of the review comments are incorporated into Revision 0. While this revision of the report is not entirely complete, it is being made available for comment, review, and evaluation. Since the report was written by several authors, sections of the report have slightly different styles. Several sections of Revision 0 are not complete, but are planned to be completed in Revision 1. The primary unfinished section is Section 3.3 on Electric Power Transmission. Other sections of Revision 0, such as Section 4.5.2 on the Energy Technology Engineering Center and 3.2 on Electric Power Generation, will be enhanced with further detailed information as it becomes available. In addition, further data, including processed response spectra for investigated facilities and cataloging of relay performance, will be added to Revision 1 depending upon investigation support. While Revision 0 of this report is being published by LLNL, Revision 1 is planned to be published by EPRI. The anticipated release date for Revision 1 is December 1995. Unfortunately, the one-year anniversary of the Northridge Earthquake was also marked by the devastating Hyogo-Ken Nanbu (or Hanshin-Awaji) Earthquake in Kobe, Japan. As compared to the Northridge Earthquake, there were many more deaths, collapsed structures, destroyed lifelines, and fires following the Kobe Earthquake. Lessons from the Kobe Earthquake will both reemphasize topics discussed in this report and provide further issues to be addressed when designing and retrofitting structures, systems, and components for seismic strong motion.

Damages of industrial equipments in the 1995 Hyougoken-Nanbu Earthquake

International Nuclear Information System (INIS)

Iwatsubo, Takuzo

1997-01-01

Hanshin-Awaji area has a population of approximately 3 million and many industries, including heavy industry, harbor facilities and international trading companies. The 1995 Hyougoken-Nanbu Earthquake occurred just in this area which is 25kmx2km oblong containing Kobe city. About 5,500 people were killed and 250,000 people lost their houses. Japan society of mechanical engineers organized the investigative committee of earthquake disaster of industrial equipments after the earthquake in order to investigate the disaster damages of industrial equipments and to give data for a design manual for mechanical equipments against earthquake excitation. This is an investigation report of the disaster damages of industrial machine equipments. Damages to machine equipment of industries in the high intensity region of the earthquake are illustrated. The mechanisms of the damages and measures against earthquake and safety of nuclear power plant design are discussed. Then it is known that the design of nuclear power plant is different from the general industrial facilities and the damage which was suffered in the general industrial facilities does not occur in the nuclear power plant. (J.P.N.)

Damages of industrial equipments in the 1995 Hyougoken-Nanbu Earthquake

Energy Technology Data Exchange (ETDEWEB)

Iwatsubo, Takuzo [Kobe Univ. (Japan). Faculty of Engineering

1997-03-01

Hanshin-Awaji area has a population of approximately 3 million and many industries, including heavy industry, harbor facilities and international trading companies. The 1995 Hyougoken-Nanbu Earthquake occurred just in this area which is 25kmx2km oblong containing Kobe city. About 5,500 people were killed and 250,000 people lost their houses. Japan society of mechanical engineers organized the investigative committee of earthquake disaster of industrial equipments after the earthquake in order to investigate the disaster damages of industrial equipments and to give data for a design manual for mechanical equipments against earthquake excitation. This is an investigation report of the disaster damages of industrial machine equipments. Damages to machine equipment of industries in the high intensity region of the earthquake are illustrated. The mechanisms of the damages and measures against earthquake and safety of nuclear power plant design are discussed. Then it is known that the design of nuclear power plant is different from the general industrial facilities and the damage which was suffered in the general industrial facilities does not occur in the nuclear power plant. (J.P.N.)

Preliminary map of peak horizontal ground acceleration for the Hanshin-Awaji earthquake of January 17, 1995, Japan - Description of Mapped Data Sets

Science.gov (United States)

Borcherdt, R.D.; Mark, R.K.

1995-01-01

The Hanshin-Awaji earthquake (also known as the Hyogo-ken Nanbu and the Great Hanshin earthquake) provided an unprecedented set of measurements of strong ground shaking. The measurements constitute the most comprehensive set of strong- motion recordings yet obtained for sites underlain by soft soil deposits of Holocene age within a few kilometers of the crustal rupture zone. The recordings, obtained on or near many important structures, provide an important new empirical data set for evaluating input ground motion levels and site amplification factors for codes and site-specific design procedures world wide. This report describes the data used to prepare a preliminary map summarizing the strong motion data in relation to seismicity and underlying geology (Wentworth, Borcherdt, and Mark., 1995; Figure 1, hereafter referred to as Figure 1/I). The map shows station locations, peak acceleration values, and generalized acceleration contours superimposed on pertinent seismicity and the geologic map of Japan. The map (Figure 1/I) indicates a zone of high acceleration with ground motions throughout the zone greater than 400 gal and locally greater than 800 gal. This zone encompasses the area of most intense damage mapped as JMA intensity level 7, which extends through Kobe City. The zone of most intense damage is parallel, but displaced slightly from the surface projection of the crustal rupture zone implied by aftershock locations. The zone is underlain by soft-soil deposits of Holocene age.

Seismic Risk Assessment of Italian Seaports Using GIS

International Nuclear Information System (INIS)

Bartolomei, Anna; Corigliano, Mirko; Lai, Carlo G.

2008-01-01

Seaports are crucial elements in the export and import of goods and/or on the flow of travellers in the tourism industry of many industrialised nations included Italy. Experience gained from recent earthquakes (e.g. 1989 Loma Prieta in USA, 1995 Hyogoken-Nanbu and 2003 Tokachi-Oki in Japan) have dramatically demonstrated the seismic vulnerability of seaport structures and the severe damage that can be caused by ground shaking. In Italy, the Department of Civil Protection has funded a research project to develop a methodology for the seismic design of new marginal wharves and assessment of existing structures at seaports located in areas of medium or high seismicity. This paper shows part of the results of this research project, currently underway, with particular reference to the seismic risk assessment through an interactive, geographically referenced database (GIS). Standard risk assessment have been carried out for the Gioia Tauro port in Calabria (Italy) using the empirical curves implemented by the National Institute of Building Sciences (NIBS, 2004)

Seismic Risk Assessment of Italian Seaports Using GIS

Science.gov (United States)

Bartolomei, Anna; Corigliano, Mirko; Lai, Carlo G.

2008-07-01

Seaports are crucial elements in the export and import of goods and/or on the flow of travellers in the tourism industry of many industrialised nations included Italy. Experience gained from recent earthquakes (e.g. 1989 Loma Prieta in USA, 1995 Hyogoken-Nanbu and 2003 Tokachi-Oki in Japan) have dramatically demonstrated the seismic vulnerability of seaport structures and the severe damage that can be caused by ground shaking. In Italy, the Department of Civil Protection has funded a research project to develop a methodology for the seismic design of new marginal wharves and assessment of existing structures at seaports located in areas of medium or high seismicity. This paper shows part of the results of this research project, currently underway, with particular reference to the seismic risk assessment through an interactive, geographically referenced database (GIS). Standard risk assessment have been carried out for the Gioia Tauro port in Calabria (Italy) using the empirical curves implemented by the National Institute of Building Sciences (NIBS, 2004).

A SEISMIC DESIGN OF NUCLEAR REACTOR BUILDING STRUCTURES APPLYING SEISMIC ISOLATION SYSTEM IN A HIGH SEISMICITY REGION –A FEASIBILITY CASE STUDY IN JAPAN-

Directory of Open Access Journals (Sweden)

TETSUO KUBO

2014-10-01

Full Text Available A feasibility study on the seismic design of nuclear reactor buildings with application of a seismic isolation system is introduced. After the Hyogo-ken Nanbu earthquake in Japan of 1995, seismic isolation technologies have been widely employed for commercial buildings. Having become a mature technology, seismic isolation systems can be applied to NPP facilities in areas of high seismicity. Two reactor buildings are discussed, representing the PWR and BWR buildings in Japan, and the application of seismic isolation systems is discussed. The isolation system employing rubber bearings with a lead plug positioned (LRB is examined. Through a series of seismic response analyses using the so-named standard design earthquake motions covering the design basis earthquake motions obtained for NPP sites in Japan, the responses of the seismic isolated reactor buildings are evaluated. It is revealed that for the building structures examined herein: (1 the responses of both isolated buildings and isolating LRBs fulfill the specified design criteria; (2 the responses obtained for the isolating LRBs first reach the ultimate condition when intensity of motion is 2.0 to 2.5 times as large as that of the design-basis; and (3 the responses of isolated reactor building fall below the range of the prescribed criteria.

A seismic design of nuclear reactor building structures applying seismic isolation system in a seismicity region-a feasibility case study in Japan

Energy Technology Data Exchange (ETDEWEB)

Kubo, Tetsuo [The University of Tokyo, Tokyo (Japan); Yamamoto, Tomofumi; Sato, Kunihiko [Mitsubishi Heavy Industries, Ltd., Kobe (Japan); Jimbo, Masakazu [Toshiba Corporation, Yokohama (Japan); Imaoka, Tetsuo [Hitachi-GE Nuclear Energy, Ltd., Hitachi (Japan); Umeki, Yoshito [Chubu Electric Power Co. Inc., Nagoya (Japan)

2014-10-15

A feasibility study on the seismic design of nuclear reactor buildings with application of a seismic isolation system is introduced. After the Hyogo-ken Nanbu earthquake in Japan of 1995, seismic isolation technologies have been widely employed for commercial buildings. Having become a mature technology, seismic isolation systems can be applied to NPP facilities in areas of high seismicity. Two reactor buildings are discussed, representing the PWR and BWR buildings in Japan, and the application of seismic isolation systems is discussed. The isolation system employing rubber bearings with a lead plug positioned (LRB) is examined. Through a series of seismic response analyses using the so-named standard design earthquake motions covering the design basis earthquake motions obtained for NPP sites in Japan, the responses of the seismic isolated reactor buildings are evaluated. It is revealed that for the building structures examined herein: (1) the responses of both isolated buildings and isolating LRBs fulfill the specified design criteria; (2) the responses obtained for the isolating LRBs first reach the ultimate condition when intensity of motion is 2.0 to 2.5 times as large as that of the design-basis; and (3) the responses of isolated reactor building fall below the range of the prescribed criteria.

Large scale centrifuge test of a geomembrane-lined landfill subject to waste settlement and seismic loading.

Science.gov (United States)

Kavazanjian, Edward; Gutierrez, Angel

2017-10-01

A large scale centrifuge test of a geomembrane-lined landfill subject to waste settlement and seismic loading was conducted to help validate a numerical model for performance based design of geomembrane liner systems. The test was conducted using the 240g-ton centrifuge at the University of California at Davis under the U.S. National Science Foundation Network for Earthquake Engineering Simulation Research (NEESR) program. A 0.05mm thin film membrane was used to model the liner. The waste was modeled using a peat-sand mixture. The side slope membrane was underlain by lubricated low density polyethylene to maximize the difference between the interface shear strength on the top and bottom of the geomembrane and the induced tension in it. Instrumentation included thin film strain gages to monitor geomembrane strains and accelerometers to monitor seismic excitation. The model was subjected to an input design motion intended to simulate strong ground motion from the 1994 Hyogo-ken Nanbu earthquake. Results indicate that downdrag waste settlement and seismic loading together, and possibly each phenomenon individually, can induce potentially damaging tensile strains in geomembrane liners. The data collected from this test is publically available and can be used to validate numerical models for the performance of geomembrane liner systems. Published by Elsevier Ltd.

The arrangement of the seismic design method of the underground facility

International Nuclear Information System (INIS)

Tanai, Kenji; Horita, Masakuni; Dewa, Katsuyuki; Gouke, Mitsuo

2002-03-01

Earthquake resistance for the underground structure is higher than the ground structure. Therefore, the case of examining the earthquake resistance of underground structure was little. However, it carries out the research on the aseismic designing method of underground structure, since the tunnel was struck by Hyogo-ken Nanbu Earthquake, and it has obtained a much knowledge. However, an object of the most study was behavior at earthquake of the comparatively shallow underground structure in the alluvial plain board, and it not carry out the examination on behavior at earthquake of underground structure in the deep rock mass. In the meantime, underground disposal facility of the high level radioactive waste constructs in the deep underground, and it carries out the operation in these tunnels. In addition, it has made almost the general process of including from the construction start to the backfilling to be about 60 years (Japan Nuclear Fuel Cycle Development Institute, 1999). During these periods, it is necessary to also consider the earthquake resistance as underground structure from the viewpoint of the safety of facilities. Then, it extracted future problem as one of the improvement of the basis information for the decision of the safety standard and guideline of the country on earthquake-resistant design of the underground disposal facility, while it carried out investigation and arrangement of earthquake-resistant design cases, guidelines and analysis method on existing underground structure, etc. And, the research items for the earthquake resistance assessment of underground structure as case study of the underground research laboratory. (author)

Proposal of new seismic assessment and retrofit technology for existing buildings; Hyogoken nanbu jishin higai wo kyokun to shita kison kozobutsu no taishin shindan system

Energy Technology Data Exchange (ETDEWEB)

Yoshioka, K.; Takahashi, Y.; Seki, M.; Tanida, M.; Akiyama, T.; Hashimoto, Y. [Obayashi Corp., Tokyo (Japan)

1995-08-10

A devastating earthquake measuring 7.2 on the JMA (Japan Meteorological Agency) magnitude hit the southern Hyogo Prefecture on January 17, 1995. This earthquake, the worst in Japan since the Great Kanto Earthquake in 1923, brought great disaster and destruction to the Hanshin area and Awajishima Island. Most of the damage to concrete and steel structures occurred in buildings designed according to former building codes. Fewer collapses occurred in buildings designed under current building code that have more severe seismic requirements. Existing buildings should be assessed by their seismic potentiality, and retrofitted to escape damage in severe earthquakes such as the Great Hanshin Earthquake. New technology for assessing and retrofitting existing buildings was developed to improve resisting performance in response to severe earthquakes. Earthquake Load or motion exceeding current requirements can be supplied to assess and retrofit existing buildings if a client wants their buildings to exhibit much stronger seismic resistance. The retrofit technologies, such as a base isolation system for whole building, vibration control bracing system with steel damper, and base isolation floor system for computer equipments, can be applied to existing buildings. 11 refs., 9 figs., 8 tabs.

Gravitational observation in central Hokkaido; Hokkaido chuobu ni okeru juryoku sokutei ni tsuite

Energy Technology Data Exchange (ETDEWEB)

Murata, Y; Makino, M [Geological Survey of Japan, Tsukuba (Japan)

1997-10-22

To compile a base map of gravity in Hokkaido, gravity was measured in central Hokkaido where gravity data are absent. Gravity anomaly was made clear in this region. Survey area was 87 km in the east-west and 224 km in the north-south. A topographic map with a scale of 25,000:1 was initially used for determining location and altitude of gravity measuring points. Since the GPS survey was found to be very useful for gravitational observation in the region of Hyogo-ken Nanbu Earthquake in 1995, the GPS has been used in this survey from 1996. Based on new measurements at 2,148 points in addition to existing points, Bouguer anomaly map was made, and density distribution of surface layer of the crust was estimated. As a result, the gravity anomaly pattern in the north-south direction and gravity anomaly in basins and volcanoes were made clear. Quantitative analysis is to be conducted using these gravity data. Using these gravity data, the density distribution of surface layer of the crust was estimated. This distribution agreed well with the geological map in this region. 4 refs., 6 figs.

Prediction of strong acceleration motion depended on focal mechanism; Shingen mechanism wo koryoshita jishindo yosoku ni tsuite

Energy Technology Data Exchange (ETDEWEB)

Kaneda, Y; Ejiri, J [Obayashi Corp., Tokyo (Japan)

1996-10-01

This paper describes simulation results of strong acceleration motion with varying uncertain fault parameters mainly for a fault model of Hyogo-ken Nanbu earthquake. For the analysis, based on the fault parameters, the strong acceleration motion was simulated using the radiation patterns and the breaking time difference of composite faults as parameters. A statistic waveform composition method was used for the simulation. For the theoretical radiation patterns, directivity was emphasized which depended on the strike of faults, and the maximum acceleration was more than 220 gal. While, for the homogeneous radiation patterns, the maximum accelerations were isotopically distributed around the fault as a center. For variations in the maximum acceleration and the predominant frequency due to the breaking time difference of three faults, the response spectral value of maximum/minimum was about 1.7 times. From the viewpoint of seismic disaster prevention, underground structures including potential faults and non-arranging properties can be grasped using this simulation. Significance of the prediction of strong acceleration motion was also provided through this simulation using uncertain factors, such as breaking time of composite faults, as parameters. 4 refs., 4 figs., 1 tab.

High-Speed Observations of Dynamic Fracture Propagation in Solids and Their Implications in Earthquake Rupture Dynamics

Science.gov (United States)

Uenishi, Koji

2016-04-01

This contribution outlines our experimental observations of seismicity-related fast fracture (rupture) propagation in solids utilising high-speed analog and digital photography (maximum frame rate 1,000,000 frames per second) over the last two decades. Dynamic fracture may be triggered or initiated in the monolithic or layered seismic models by detonation of micro explosives, a projectile launched by a gun, laser pulses and electric discharge impulses, etc. First, we have investigated strike-slip rupture along planes of weakness in transparent photoelastic (birefringent) materials at a laboratory scale and shown (at that time) extraordinarily fast rupture propagation in a bi-material system and its possible effect on the generation of large strong motion in the limited narrow areas in the Kobe region on the occasion of the 1995 Hyogo-ken Nanbu, Japan, earthquake (Uenishi Ph.D. thesis 1997, Uenishi et al. BSSA 1999). In this series of experiments, we have also modelled shallow dip-slip earthquakes and indicated a possible origin of the asymmetric ground motion in the hanging and foot-walls. In the photoelastic photographs, we have found the unique dynamic wave interaction and generation of specific shear and interface waves numerically predicted by Uenishi and Madariaga (Eos 2005), and considered as a case study the seismic motion associated with the 2014 Nagano-ken Hokubu (Kamishiro Fault), Japan, dip-slip earthquake (Uenishi EFA 2015). Second, we have experimentally shown that even in a monolithic material, rupture speed may exceed the local shear wave speed if we employ hyperelasically behaving materials like natural rubber (balloons) (Uenishi Eos 2006, Uenishi ICF 2009, Uenishi Trans. JSME A 2012) but fracture in typical monolithic thin fluid films (e.g. soap bubbles, which may be treated as a solid material) propagates at an ordinary subsonic (sub-Rayleigh) speed (Uenishi et al. SSJ 2006). More recent investigation handling three-dimensional rupture propagation

Estimation of underground structures in the Osaka-Kobe area by array-network observations of microtremors; Bido no array kansoku ni yoru Osaka-Hyogo chiiki no chika kozo no suitei

Energy Technology Data Exchange (ETDEWEB)

Okada, H; Ishikawa, K; Ling, S [Hokkaido University, Sapporo (Japan); Sasabe, K [Ministry of Construction, Tokyo (Japan)

1997-05-27

Microtremor observations have been carried out with an objective to estimate underground structures including the foundation depth in the Osaka-Kobe area which has been greatly damaged by the Hyogoken-nanbu earthquake in 1995. Different organizations have made seismic surveys and boring investigations in this area, by which elucidation has been made on the underground structures. The present observations are intended to identify S-wave velocity distribution in a wide area from the ground surface to the foundation, which is difficult to be verified by using conventional surveys and investigations. Methods to detect surface waves which are contained in microtremors include the frequency-wave number method (the F-K method) and the spatial autocorrelation method (the SPAC method). The SPAC method can estimate phase velocities of longer waves for the size of an array than with the F-K method, and is more advantageous in estimating ground structures at greater depths. S-wave velocity structure was estimated down to the foundation rocks existing in depths of about 0.5 to 2.0 km. For estimating the phase velocities in Raleigh waves, the SPAC method and the expanded spatial autocorrelation method were used. The underground structures thus derived showed a good agreement with the results of explorations using other methods. 8 figs., 1 tab.

Experiment for deep seismic reflections in Hidaka, Hokkaido. Comparison between Vibroseis and explosive data; Hidaka chiiki ni okeru shinbu hanno data no shutoku jikken. Vibroseis to dynamite no hikaku

Energy Technology Data Exchange (ETDEWEB)

Shimizu, N; Ikawa, T [Japex Jeoscience Institute, Tokyo (Japan); Ito, T; Tsumura, N; Shinohara, M; Ikawa, T. Ikawa, H.; Asano, Y; Tanaka, Y; Miyazono, N [Chiba University, Chiba (Japan); Arita, K; Moriya, T; Otsuka, K; Omura, T [Hokkaido University, Sapporo (Japan); Kimura, M [Osaka Prefectural University, Osaka (Japan); Hirata, N [The University of Tokyo, Tokyo (Japan); Okuike, S

1997-05-27

This is a prompt report. These days the importance of acquiring knowledge about the structure from the lower crust down to the upper mantle is often discussed with reference taken to Hyogo-ken Nanbu Earthquake. The Hidaka collision belt where the lower crust is exposed on the surface is a rare phenomenon in the world and has been the subject of seismic survey. As a part of the survey, experiments are conducted by the use of vibrations produced by Vibroseis and dynamite sources. Every one of the shot records (20-second record) from the two types of vibration sources contains a clear echo in the vicinity of 16 seconds supposedly from a level deeper than 40 kilometers, not to mention reflections from shallow levels. Although some studies have to be conducted before the reflecting geological boundary (possibly the upper mantle) of the echo near the 16-second point can be identified, yet this is probably the reflection from the deepest level ever obtained in the seismic reflection survey conducted in Japan`s land area. It is proved by this experiment that vibration from a vibrator can reach as far as that from explosion if the vibrator specifications are rightly chosen. 4 refs., 3 figs.

Active fault and other geological studies for seismic assessment: present state and problems

International Nuclear Information System (INIS)

Kakimi, Toshihiro

1997-01-01

Evaluation system of earthquakes from an active fault is, in Japan, based on the characteristic earthquake model of a wide sense that postulates essentially the same (nearly the maximum) magnitude and recurrence interval during the recent geological times. Earthquake magnitude M is estimated by empirical relations among M, surface rupture length L, and surface fault displacement D per event of the earthquake faults on land in Japan. Recurrence interval R of faulting/earthquake is calculated from D and the long-term slip rate S of a fault as R=D/S. Grouping or segmentation of complicatedly distributed faults is an important, but difficult problem in order to distinguish a seismogenic fault unit corresponding to an individual characteristic earthquake. If the time t of the latest event is obtained, the 'cautiousness' of a fault can be judged from R-t or t/R. According to this idea, several faults whose t/R exceed 0.5 have been designated as the 'precaution faults' having higher probability of earthquake occurrence than the others. A part of above evaluation has been introduced at first into the seismic-safety examination system of NPPs in 1978. According to the progress of research on active faults, the weight of interest in respect to the seismic hazard assessment shifted gradually from the historic data to the fault data. Most of recent seismic hazard maps have been prepared in consideration with active faults on land in Japan. Since the occurrence of the 1995 Hyogoken-Nanbu earthquake, social attention has been concentrated upon the seismic hazard due to active faults, because this event was generated from a well-known active fault zone that had been warned as a 'precaution fault'. In this paper, a few recent topics on other geological and geotechnical researches aiming at improving the seismic safety of NPPs in Japan were also introduced. (J.P.N.)

Active fault and other geological studies for seismic assessment: present state and problems

Energy Technology Data Exchange (ETDEWEB)

Kakimi, Toshihiro [Nuclear Power Engineering Corp., Tokyo (Japan)

1997-03-01

Evaluation system of earthquakes from an active fault is, in Japan, based on the characteristic earthquake model of a wide sense that postulates essentially the same (nearly the maximum) magnitude and recurrence interval during the recent geological times. Earthquake magnitude M is estimated by empirical relations among M, surface rupture length L, and surface fault displacement D per event of the earthquake faults on land in Japan. Recurrence interval R of faulting/earthquake is calculated from D and the long-term slip rate S of a fault as R=D/S. Grouping or segmentation of complicatedly distributed faults is an important, but difficult problem in order to distinguish a seismogenic fault unit corresponding to an individual characteristic earthquake. If the time t of the latest event is obtained, the `cautiousness` of a fault can be judged from R-t or t/R. According to this idea, several faults whose t/R exceed 0.5 have been designated as the `precaution faults` having higher probability of earthquake occurrence than the others. A part of above evaluation has been introduced at first into the seismic-safety examination system of NPPs in 1978. According to the progress of research on active faults, the weight of interest in respect to the seismic hazard assessment shifted gradually from the historic data to the fault data. Most of recent seismic hazard maps have been prepared in consideration with active faults on land in Japan. Since the occurrence of the 1995 Hyogoken-Nanbu earthquake, social attention has been concentrated upon the seismic hazard due to active faults, because this event was generated from a well-known active fault zone that had been warned as a `precaution fault`. In this paper, a few recent topics on other geological and geotechnical researches aiming at improving the seismic safety of NPPs in Japan were also introduced. (J.P.N.)

Earthquake and welded structures 5: Earthquake damages and anti-earthquake measures of oil storage tanks; 5 kikenbutsu chozo tank no jishin higai to taishin taisaku

Energy Technology Data Exchange (ETDEWEB)

Kawano, K. [Chiyoda Chemical Engineering and Construction Co. Ltd., Tokyo (Japan)

1997-09-05

The result of field investigation carried out on the state of damages of 236 hazardous material storage tanks out of 687 caused by the Hyogoken Nambu Earthquake in 1995 is introduced together with the cases of damage and the description of the countermeasures. The events of inclination and settlement of tank bodies were confirmed in 44% among those investigated in particular with tanks having a capacity of less than 1000kl and as for the basement and ground settlement, the fact that sand spouted as a result of their fluidization was witnessed as much as 81% among those investigated and the area surrounding tanks was roughly agreed with the area where ground crack appeared. A great number of other damages such as cracking of preventive seals against rain water, breakdown of oil defense banks and so forth were also confirmed. In the latter half of the report, aseismatic standards of old and new regulations as well as on the new criterion concerning the outdoor storage tank body, its basement and ground are tabulated and 4 items of anti-earthquake measures such as the final structural check up with regard to an earthquake exceeding the designed permissible stress, consolidation of tank body structure on the basis of the revised seismic coefficient method, assurance of the steadfast basement, prevention of the elevated platform from falling down and strengthening of water-proof seals and oil defense banks are enumerated in accordance with the report of investigation and examination on the resistibility of hazardous material storage equipment against the earthquake. 3 refs., 5 figs., 3 tabs.

Seismic ACROSS Transmitter Installed at Morimachi above the Subducting Philippine Sea Plate for the Test Monitoring of the Seismogenic Zone of Tokai Earthquake not yet to Occur

Science.gov (United States)

Kunitomo, T.; Kumazawa, M.; Masuda, T.; Morita, N.; Torii, T.; Ishikawa, Y.; Yoshikawa, S.; Katsumata, A.; Yoshida, Y.

2008-12-01

Here we report the first seismic monitoring system in active and constant operation for the wave propagation characteristics in tectonic region just above the subducting plate driving the coming catastrophic earthquakes. Developmental works of such a system (ACROSS; acronym for Accurately Controlled, Routinely Operated, Signal System) have been started in 1994 at Nagoya University and since 1996 also at TGC (Tono Geoscience Center) of JAEA promoted by Hyogoken Nanbu Earthquakes (1995 Jan.17, Mj=7.3). The ACROSS is a technology system including theory of signal and data processing based on the brand new concept of measurement methodology of Green function between a signal source and observation site. The works done for first generation system are reported at IWAM04 and in JAEA report (Kumazawa et al.,2007). The Meteorological Research Institute of JMA has started a project of test monitoring of Tokai area in 2004 in corporation with Shizuoka University to realize the practical use of the seismic ACROSS for earthquake prediction researches. The first target was set to Tokai Earthquake not yet to take place. The seismic ACROSS transmitter was designed so as to be appropriate for the sensitive monitoring of the deep active fault zone on the basis of the previous technology elements accumulated so far. The ground coupler (antenna) is a large steel-reinforced concrete block (over 20m3) installed in the basement rocks in order to preserve the stability. Eccentric moment of the rotary transmitter is 82 kgm at maximum, 10 times larger than that of the first generation. Carrier frequency of FM signal for practical use can be from 3.5 to 15 Hz, and the signal phase is accurately controlled by a motor with vector inverter synchronized with GPS clock with a precision of 10-4 radian or better. By referring to the existing structure model in this area (Iidaka et al., 2003), the site of the transmitting station was chosen at Morimachi so as to be appropriate for detecting the

Sea bottom gravity survey of Osaka bay and its study; Osakawan kaitei juryoku chosa to sono kosatsu

Energy Technology Data Exchange (ETDEWEB)

Komazawa, M [Geological Survey of Japan, Tsukuba (Japan); Ota, Y; Shibuya, S; Kumai, M; Murakami, M [Japex Geoscience Institute, Inc., Tokyo (Japan)

1996-05-01

This paper reports a sea bottom gravity survey conducted with an objective to identify deep underground structure in the vicinity of the epicenter of the Hyogoken-Nanbu Earthquake. The surveyed areas are the whole Osaka Bay area north of the north latitude of 34 degrees and 20 minutes, and the eastern part of the Sea of Harima east of the east longitude of 134 degrees and 40 minutes, excluding the areas difficult of performing measurements. A square lattice with sides each about 2 km was arranged with 408 measurement points. The measurement was carried out by using an observation vessel mounted with a sea bottom gravimeter made by LaCoste and Romberg Corporation, which was lowered down to the sea bottom at the measurement points. Errors in positions and water depths at the gravity measuring points were suppressed to less than 0.002 minutes and 0.1 m, respectively. The measurement data were given necessary corrections by using a unified method applicable also to land areas, and a Bouguer anomaly chart was prepared. Based on the chart, this paper summarizes features in the Bouguer anomaly in the surveyed areas (such as the low-gravity anomaly band extending the central part of the Osaka bay from north-east to south-west, and the gradient structure existing on the Awaji island side). 6 refs., 1 fig.

Reduction of artificial source effect in the high-resolution aeromagnetic survey in the Hanshin region; Hanshin chiiki no komitsudo kuchu jiki tansa ni okeru jinko noise source no eikyo no jokyo

Energy Technology Data Exchange (ETDEWEB)

Nakatsuka, T; Makino, M; Morijiri, R; Okuma, S [Geological Survey of Japan, Tsukuba (Japan)

1997-05-27

A high-resolution aeromagnetic survey was carried out in December 1995 on areas from Kobe City to Kyoto City in relation to the Hyogoken-nanbu Earthquake in 1995. It was found in the survey that effects of electric trains driven by direct current and man-made structures cannot be avoided, working as a large noise factor in extraction and analysis of geological information. This paper describes a quantitative analysis on magnetic anomaly suspected to have been caused from artificial sources seen in the magnetic map of the Hanshin area obtained from the above exploration data. The paper also gives considerations on methods to remove the effects therefrom. It then describes a quantitative analysis and the result of attempts on removal of the anomaly, taking up the following factors: (1) distribution of specific and remarkable magnetic anomalies which correspond to railroad positions of the Hanshin Railways running through the Nishinomiya-Toyonaka area, (2) the magnetic anomaly trend in positive and negative pair seen in the seafront area of Kobe City, and (3) typical bipolar isolated type magnetic anomaly in the north-west part of Kobe City. The cause for (1) was loop current flown for the railway operation, that for (2) was man-made structures in the improved seafront area, and that for (3) was a provisionally built metal waste storage yard. 9 figs.

A new Azuki bean variety, Beni-Nanbu

International Nuclear Information System (INIS)

Satoh, Tadao; Takahashi, Yasutoshi; Kamata, Nobuaki

1984-01-01

In January of 1979, a new Azuki bean cultivar, which was developed by the mutation breeding, was named Beni-Nanbu and released to farmers in Iwate-prefecture. Beni-Nanbu, which was developed by Iwate Agricultural Experiment Station, was derived from seeds irradiated by gamma rays ( 60 Co), 10 kR dose, at the Institute of Radiation Breeding, NIAS, MAFF. The original cultivar, Monbetsu 26, is very late maturing with long stem which often causes lodging and yield reduction, although it is resistant to virus disease and has good grain quality. Therefore, this breeding project was set to get short statued and early maturing mutants. The number of the original Monbetsu 26 seeds given irradiation was about 2,500. Beni-Nanbu is about 13 days earlier in flowering, and about 10 days in maturing than the original Monbetsu 26, being the medium-late group in Iwate-prefecture. Stem is about 20 cm shortened, reducing excessive vine growth and lodging. Beni-nanbu has a determinate and closed plant type, with abundant branches and dark brown pods. Grain quality is excellent in seed color, luster, and grain size uniformity. Grain yield is stable, less affected by climate and farming practice. Beni-Nanbu outyields Iwate-Dainagon and Odate 2 by 18% and 9%, respectively. It has a medium resistance to virus disease, similar to the original cultivar, superior to Iwate-Dainagon. (author)

Sealing process with calcite in the Nojima active fault zone revealed from isotope analysis of calcite

International Nuclear Information System (INIS)

Arai, Takashi; Tsukahara, Hiroaki; Morikiyo, Toshiro

2003-01-01

The Nojima fault appeared on the surface in the northern part of Awaji Island, central Japan as a result of the Hyogo-ken Nanbu earthquake (1995, M=7.2). Active fault drilling was performed by the Disaster Prevention Research Institute (DPRI), Kyoto University, and core samples were retrieved from 1410 to 1710 m, which were composed of intact and fractured granodiorites. We obtained calcite samples and gas samples from the vein in marginal fracture and non-fracture zones. We analyzed the carbon and oxygen isotope ratios of calcite and carbon dioxide to investigate the characteristic isotope ratios of fluids in the active fault zone, to estimate the origins of fluids, and to determine the sealing process of fractures. The analyzed values of carbon and oxygen isotope ratios of calcite were -10.3 to -7.2 per mille, 18 to 23 per mille, respectively, and carbon isotope ratios of CO 2 were -21 to -17 per mille. If carbon isotope ratios of calcite were at equilibrium with those of CO 2 , the precipitation temperature of calcite is calculated to be 30 to 50 deg C. This temperature is consistent with the present temperature of the depth where drilling cores were retrieved. Oxygen isotope ratios of H 2 O that, precipitated calcite were calculated to be -1.8 to -5.5 per mille. These values indicate calcite were precipitated from mixed fluids of sea water and meteoric water. Therefore, the marginal fracture zone of the Nojima fault was sealed with calcite, which was generated from mixing of sea water and meteoric water in situ. (author)

Mathematical Modeling of Column-Base Connections under Monotonic Loading

Directory of Open Access Journals (Sweden)

Gholamreza Abdollahzadeh

2014-12-01

Full Text Available Some considerable damage to steel structures during the Hyogo-ken Nanbu Earthquake occurred. Among them, many exposed-type column bases failed in several consistent patterns, such as brittle base plate fracture, excessive bolt elongation, unexpected early bolt failure, and inferior construction work, etc. The lessons from these phenomena led to the need for improved understanding of column base behavior. Joint behavior must be modeled when analyzing semi-rigid frames, which is associated with a mathematical model of the moment–rotation curve. The most accurate model uses continuous nonlinear functions. This article presents three areas of steel joint research: (1 analysis methods of semi-rigid joints; (2 prediction methods for the mechanical behavior of joints; (3 mathematical representations of the moment–rotation curve. In the current study, a new exponential model to depict the moment–rotation relationship of column base connection is proposed. The proposed nonlinear model represents an approach to the prediction of M–θ curves, taking into account the possible failure modes and the deformation characteristics of the connection elements. The new model has three physical parameters, along with two curve-fitted factors. These physical parameters are generated from dimensional details of the connection, as well as the material properties. The M–θ curves obtained by the model are compared with published connection tests and 3D FEM research. The proposed mathematical model adequately comes close to characterizing M–θ behavior through the full range of loading/rotations. As a result, modeling of column base connections using the proposed mathematical model can give crucial beforehand information, and overcome the disadvantages of time consuming workmanship and cost of experimental studies.

Evaluation of earthquake vibration on aseismic design of nuclear power plant judging from recent earthquakes

International Nuclear Information System (INIS)

Dan, Kazuo

2006-01-01

The Regulatory Guide for Aseismic Design of Nuclear Reactor Facilities was revised on 19 th September, 2006. Six factors for evaluation of earthquake vibration are considered on the basis of the recent earthquakes. They are 1) evaluation of earthquake vibration by method using fault model, 2) investigation and approval of active fault, 3) direct hit earthquake, 4) assumption of the short active fault as the hypocentral fault, 5) locality of the earthquake and the earthquake vibration and 6) remaining risk. A guiding principle of revision required new evaluation method of earthquake vibration using fault model, and evaluation of probability of earthquake vibration. The remaining risk means the facilities and people get into danger when stronger earthquake than the design occurred, accordingly, the scattering has to be considered at evaluation of earthquake vibration. The earthquake belt of Hyogo-Nanbu earthquake and strong vibration pulse in 1995, relation between length of surface earthquake fault and hypocentral fault, and distribution of seismic intensity of off Kushiro in 1993 are shown. (S.Y.)

1000m depth boring at Inagawa, Hyogo prefecture. 1. Overviews; Hyogoken Inagawamachi ni okeru 1000m boring chosa. 1. Gaiyo

Energy Technology Data Exchange (ETDEWEB)

Sato, T; Kusunose, K; Cho, A; Tosha, T [Geological Survey of Japan, Tsukuba (Japan); Kiyama, T; Yamada, F [Mitsui Construction Co. Ltd., Tokyo (Japan); Aizawa, T [Sancoh Consultants Co. Ltd., Tokyo (Japan)

1996-05-01

Various field experiments were carried out using a 1000m deep borehole at Inagawa town, about 10km north of the focus of the Hanshin-Awaji Great Earthquake and directly above the area where shallow earthquake activities have intermittently occurred. These experiments included stress measurement by hydraulic fracturing, hydrophone-aided VSP, permeability tests and observation of various types of logging. The laboratory experiments were also carried out, including measurement of various properties and stresses of the core samples. The stress-depth relationship, determined by the hydraulic fracturing method, shows that the stress gradient well coincides with the Western Japan standard at a depth up to 700m, whereas it is approximately twice as high as the standard at a depth of 946m, at which core disking and borehole break-out are clearly observed, and hence stresses conceivably concentrate locally. Orientation of the maximum horizontal compressive stress is E-W at a depth of around 600m, but greatly changes to NNW-SSE at a deeper position. 4 refs., 5 figs.

Geometry of the Nojima fault at Nojima-Hirabayashi, Japan - I. A simple damage structure inferred from borehole core permeability

Science.gov (United States)

Lockner, David A.; Tanaka, Hidemi; Ito, Hisao; Ikeda, Ryuji; Omura, Kentaro; Naka, Hisanobu

2009-01-01

The 1995 Kobe (Hyogo-ken Nanbu) earthquake, M = 7.2, ruptured the Nojima fault in southwest Japan. We have studied core samples taken from two scientific drillholes that crossed the fault zone SW of the epicentral region on Awaji Island. The shallower hole, drilled by the Geological Survey of Japan (GSJ), was started 75 m to the SE of the surface trace of the Nojima fault and crossed the fault at a depth of 624 m. A deeper hole, drilled by the National Research Institute for Earth Science and Disaster Prevention (NIED) was started 302 m to the SE of the fault and crossed fault strands below a depth of 1140 m. We have measured strength and matrix permeability of core samples taken from these two drillholes. We find a strong correlation between permeability and proximity to the fault zone shear axes. The half-width of the high permeability zone (approximately 15 to 25 m) is in good agreement with the fault zone width inferred from trapped seismic wave analysis and other evidence. The fault zone core or shear axis contains clays with permeabilities of approximately 0.1 to 1 microdarcy at 50 MPa effective confining pressure (10 to 30 microdarcy at in situ pressures). Within a few meters of the fault zone core, the rock is highly fractured but has sustained little net shear. Matrix permeability of this zone is approximately 30 to 60 microdarcy at 50 MPa effective confining pressure (300 to 1000 microdarcy at in situ pressures). Outside this damage zone, matrix permeability drops below 0.01 microdarcy. The clay-rich core material has the lowest strength with a coefficient of friction of approximately 0.55. Shear strength increases with distance from the shear axis. These permeability and strength observations reveal a simple fault zone structure with a relatively weak fine-grained core surrounded by a damage zone of fractured rock. In this case, the damage zone will act as a high-permeability conduit for vertical and horizontal flow in the plane of the

High stresses stored in fault zones: example of the Nojima fault (Japan)

Science.gov (United States)

Boullier, Anne-Marie; Robach, Odile; Ildefonse, Benoît; Barou, Fabrice; Mainprice, David; Ohtani, Tomoyuki; Fujimoto, Koichiro

2018-04-01

During the last decade pulverized rocks have been described on outcrops along large active faults and attributed to damage related to a propagating seismic rupture front. Questions remain concerning the maximal lateral distance from the fault plane and maximal depth for dynamic damage to be imprinted in rocks. In order to document these questions, a representative core sample of granodiorite located 51.3 m from the Nojima fault (Japan) that was drilled after the Hyogo-ken Nanbu (Kobe) earthquake is studied by using electron backscattered diffraction (EBSD) and high-resolution X-ray Laue microdiffraction. Although located outside of the Nojima damage fault zone and macroscopically undeformed, the sample shows pervasive microfractures and local fragmentation. These features are attributed to the first stage of seismic activity along the Nojima fault characterized by laumontite as the main sealing mineral. EBSD mapping was used in order to characterize the crystallographic orientation and deformation microstructures in the sample, and X-ray microdiffraction was used to measure elastic strain and residual stresses on each point of the mapped quartz grain. Both methods give consistent results on the crystallographic orientation and show small and short wavelength misorientations associated with laumontite-sealed microfractures and alignments of tiny fluid inclusions. Deformation microstructures in quartz are symptomatic of the semi-brittle faulting regime, in which low-temperature brittle plastic deformation and stress-driven dissolution-deposition processes occur conjointly. This deformation occurred at a 3.7-11.1 km depth interval as indicated by the laumontite stability domain. Residual stresses are calculated from deviatoric elastic strain tensor measured using X-ray Laue microdiffraction using the Hooke's law. The modal value of the von Mises stress distribution is at 100 MPa and the mean at 141 MPa. Such stress values are comparable to the peak strength of a

High stresses stored in fault zones: example of the Nojima fault (Japan

Directory of Open Access Journals (Sweden)

A.-M. Boullier

2018-04-01

Full Text Available During the last decade pulverized rocks have been described on outcrops along large active faults and attributed to damage related to a propagating seismic rupture front. Questions remain concerning the maximal lateral distance from the fault plane and maximal depth for dynamic damage to be imprinted in rocks. In order to document these questions, a representative core sample of granodiorite located 51.3 m from the Nojima fault (Japan that was drilled after the Hyogo-ken Nanbu (Kobe earthquake is studied by using electron backscattered diffraction (EBSD and high-resolution X-ray Laue microdiffraction. Although located outside of the Nojima damage fault zone and macroscopically undeformed, the sample shows pervasive microfractures and local fragmentation. These features are attributed to the first stage of seismic activity along the Nojima fault characterized by laumontite as the main sealing mineral. EBSD mapping was used in order to characterize the crystallographic orientation and deformation microstructures in the sample, and X-ray microdiffraction was used to measure elastic strain and residual stresses on each point of the mapped quartz grain. Both methods give consistent results on the crystallographic orientation and show small and short wavelength misorientations associated with laumontite-sealed microfractures and alignments of tiny fluid inclusions. Deformation microstructures in quartz are symptomatic of the semi-brittle faulting regime, in which low-temperature brittle plastic deformation and stress-driven dissolution-deposition processes occur conjointly. This deformation occurred at a 3.7–11.1 km depth interval as indicated by the laumontite stability domain. Residual stresses are calculated from deviatoric elastic strain tensor measured using X-ray Laue microdiffraction using the Hooke's law. The modal value of the von Mises stress distribution is at 100 MPa and the mean at 141 MPa. Such stress values are comparable to

Radon survey in outdoor workplaces of the Nanbu area

International Nuclear Information System (INIS)

Iyogi, Takashi; Hisamatsu, Shunichi; Sakurai, Naoyuki; Koyama, Kenji

1999-01-01

We previously surveyed indoor Rn concentration in homes throughout Aomori Prefecture from 1991 to 1995, and found a mean Rn concentration of 9 Bq m -3 . For accurate evaluation of radiation dose from Rn, its concentration not only in the home but also in workplaces and schools is important, since workers and students spend approximately one-third of the day in these places. Then, we obtained indoor Rn concentrations in several workplaces and schools in Aomori Prefecture. Now, measurements of outdoor Rn in workplaces have been planned for the prefecture during a two year period. The results for half the prefecture, the Nanbu area are described here. Passive Rn detectors using polycarbonate film were employed for long-term monitoring. Diurnal variations of Rn and its daughter nuclides were measured by an active Rn detector with an ionization chamber and a working level meter, respectively. The geometric mean Rn concentration obtained with the passive detectors was approximately 3 Bq m -3 in the outdoor workplaces, and lower than that in the indoor workplaces and school (14 Bq m -3 ). The Rn concentrations in fishing boats and harbors were slightly lower than typical values and some data for forests were higher than other workplaces. The diurnal variations which were higher at night and lower during the day were observed by the active detectors. (author)

Injector system design of the 8 GeV synchrotron radiation facility (SPring-8)

International Nuclear Information System (INIS)

Harami, T.; Yokomizo, H.; Ohtsuka, H.

1990-01-01

The 8 GeV synchrotron radiation facility, named SPring-8, which will be constructed at Nishi-harima in Hyogo-ken, is designed jointly by JAERI (Japan Atomic Energy Research Institute and RIKEN (Institute of Physical and Chemical Research) under the supervision of Science and Technology Agency (STA) of the Japanese government. The facility provides photon in the X-ray and hard X-ray domains with high flux and high brilliance. The major characteristics of the storage ring are the low emittance and the large number of straight sections. Combining the low emittance beam with long insertion devices, several orders of magnitude improvement in intensity and brightness are expected. The injector system of SPring-8 is composed of a linac and a synchrotron. Not only electrons but positrons can be accelerated by the linac. These particles are injected into the synchrotron and further accelerated to 8 GeV. (N.K.)

Polarimetric borehole radar measurement near Nojima fault and its application to subsurface crack characterization; Polarimetric borehole radar ni yoru Nojima danso shuhen no chika kiretsu keisoku jikken

Energy Technology Data Exchange (ETDEWEB)

Sato, M.; Taniguchi, Y.; Miwa, T.; Niitsuma, H. [Tohoku University, Sendai (Japan); Ikeda, R. [National Research Institute for Disaster Prevention, Tsukuba (Japan); Makino, K. [Geophysical Surveying and Consulting Co. Ltd., Tokyo (Japan)

1997-05-27

Practical application of subsurface crack characterization by the borehole radar measurement to which the radar polarimetric method was introduced was attempted to measuring objects for which the borehole radar has not been much used, for example, the inside of low loss rock mass or fracture zone where cracks tightly exist. A system was trially manufactured which makes the radar polarimetric measurement possible in the borehole at a 1000m depth and with a about 10cm diameter, and a field experiment was conducted for realizing the subsurface crack characterization near the Nojima fault. For the measuring experiment by the polarimetric borehole radar, used were Iwaya borehole and Hirabayashi borehole drilled in the north of Awaji-shima, Hyogo-ken. In a comparison of both polarization systems of Hirabayashi borehole, reflected waves at depths of 1038m and 1047m are relatively stronger in both polarization systems than those with the same polarization form and at different depths, whereas reflected waves around a 1017m depth are strong only as to the parallel polarization system. Characteristics of the polarization in this experiment indirectly reflect crack structures. 6 refs., 6 figs., 1 tab.

Renewal of K-NET (National Strong-motion Observation Network of Japan)

Science.gov (United States)

Kunugi, T.; Fujiwara, H.; Aoi, S.; Adachi, S.

2004-12-01

The National Research Institute for Earth Science and Disaster Prevention (NIED) operates K-NET (Kyoshin Network), the national strong-motion observation network, which evenly covers the whole of Japan at intervals of 25 km on average. K-NET was constructed after the Hyogoken-Nambu (Kobe) earthquake in January 1995, and began operation in June 1996. Thus, eight years have passed since K-NET started, and large amounts of strong-motion records have been obtained. As technology has progressed and new technologies have become available, NIED has developed a new K-NET with improved functionality. New seismographs have been installed at 443 observatories mainly in southwestern Japan where there is a risk of strong-motion due to the Nankai and Tonankai earthquakes. The new system went into operation in June 2004, although seismographs have still to be replaced in other areas. The new seismograph (K-NET02) consists of a sensor module, a measurement module and a communication module. A UPS, a GPS antenna and a dial-up router are also installed together with a K-NET02. A triaxial accelerometer, FBA-ES-DECK (Kinemetrics Inc.) is built into the sensor module. The measurement module functions as a conventional strong-motion seismograph for high-precision observation. The communication module can perform sophisticated processes, such as calculation of the Japan Meteorological Agency (JMA) seismic intensity, continuous recording of data and near real-time data transmission. It connects to the Data Management Center (DMC) using an ISDN line. In case of a power failure, the measurement module can control the power supply to the router and the communication module to conserve battery power. One of the main features of K-NET02 is a function for processing JMA seismic intensity. K-NET02 functions as a proper seismic intensity meter that complies with the official requirements of JMA, although the old strong-motion seismograph (K-NET95) does not calculate seismic intensity. Another

Connecting slow earthquakes to huge earthquakes.

Science.gov (United States)

Obara, Kazushige; Kato, Aitaro

2016-07-15

Slow earthquakes are characterized by a wide spectrum of fault slip behaviors and seismic radiation patterns that differ from those of traditional earthquakes. However, slow earthquakes and huge megathrust earthquakes can have common slip mechanisms and are located in neighboring regions of the seismogenic zone. The frequent occurrence of slow earthquakes may help to reveal the physics underlying megathrust events as useful analogs. Slow earthquakes may function as stress meters because of their high sensitivity to stress changes in the seismogenic zone. Episodic stress transfer to megathrust source faults leads to an increased probability of triggering huge earthquakes if the adjacent locked region is critically loaded. Careful and precise monitoring of slow earthquakes may provide new information on the likelihood of impending huge earthquakes. Copyright © 2016, American Association for the Advancement of Science.

Connecting slow earthquakes to huge earthquakes

OpenAIRE

Obara, Kazushige; Kato, Aitaro

2016-01-01

Slow earthquakes are characterized by a wide spectrum of fault slip behaviors and seismic radiation patterns that differ from those of traditional earthquakes. However, slow earthquakes and huge megathrust earthquakes can have common slip mechanisms and are located in neighboring regions of the seismogenic zone. The frequent occurrence of slow earthquakes may help to reveal the physics underlying megathrust events as useful analogs. Slow earthquakes may function as stress meters because of th...

The HayWired Earthquake Scenario—Earthquake Hazards

Science.gov (United States)

Detweiler, Shane T.; Wein, Anne M.

2017-04-24

The HayWired scenario is a hypothetical earthquake sequence that is being used to better understand hazards for the San Francisco Bay region during and after an earthquake of magnitude 7 on the Hayward Fault. The 2014 Working Group on California Earthquake Probabilities calculated that there is a 33-percent likelihood of a large (magnitude 6.7 or greater) earthquake occurring on the Hayward Fault within three decades. A large Hayward Fault earthquake will produce strong ground shaking, permanent displacement of the Earth’s surface, landslides, liquefaction (soils becoming liquid-like during shaking), and subsequent fault slip, known as afterslip, and earthquakes, known as aftershocks. The most recent large earthquake on the Hayward Fault occurred on October 21, 1868, and it ruptured the southern part of the fault. The 1868 magnitude-6.8 earthquake occurred when the San Francisco Bay region had far fewer people, buildings, and infrastructure (roads, communication lines, and utilities) than it does today, yet the strong ground shaking from the earthquake still caused significant building damage and loss of life. The next large Hayward Fault earthquake is anticipated to affect thousands of structures and disrupt the lives of millions of people. Earthquake risk in the San Francisco Bay region has been greatly reduced as a result of previous concerted efforts; for example, tens of billions of dollars of investment in strengthening infrastructure was motivated in large part by the 1989 magnitude 6.9 Loma Prieta earthquake. To build on efforts to reduce earthquake risk in the San Francisco Bay region, the HayWired earthquake scenario comprehensively examines the earthquake hazards to help provide the crucial scientific information that the San Francisco Bay region can use to prepare for the next large earthquake, The HayWired Earthquake Scenario—Earthquake Hazards volume describes the strong ground shaking modeled in the scenario and the hazardous movements of

Earthquakes

Science.gov (United States)

An earthquake happens when two blocks of the earth suddenly slip past one another. Earthquakes strike suddenly, violently, and without warning at any time of the day or night. If an earthquake occurs in a populated area, it may cause ...

The Challenge of Centennial Earthquakes to Improve Modern Earthquake Engineering

International Nuclear Information System (INIS)

Saragoni, G. Rodolfo

2008-01-01

The recent commemoration of the centennial of the San Francisco and Valparaiso 1906 earthquakes has given the opportunity to reanalyze their damages from modern earthquake engineering perspective. These two earthquakes plus Messina Reggio Calabria 1908 had a strong impact in the birth and developing of earthquake engineering. The study of the seismic performance of some up today existing buildings, that survive centennial earthquakes, represent a challenge to better understand the limitations of our in use earthquake design methods. Only Valparaiso 1906 earthquake, of the three considered centennial earthquakes, has been repeated again as the Central Chile, 1985, Ms = 7.8 earthquake. In this paper a comparative study of the damage produced by 1906 and 1985 Valparaiso earthquakes is done in the neighborhood of Valparaiso harbor. In this study the only three centennial buildings of 3 stories that survived both earthquakes almost undamaged were identified. Since for 1985 earthquake accelerogram at El Almendral soil conditions as well as in rock were recoded, the vulnerability analysis of these building is done considering instrumental measurements of the demand. The study concludes that good performance of these buildings in the epicentral zone of large earthquakes can not be well explained by modern earthquake engineering methods. Therefore, it is recommended to use in the future of more suitable instrumental parameters, such as the destructiveness potential factor, to describe earthquake demand

Earthquake prediction

International Nuclear Information System (INIS)

Ward, P.L.

1978-01-01

The state of the art of earthquake prediction is summarized, the possible responses to such prediction are examined, and some needs in the present prediction program and in research related to use of this new technology are reviewed. Three basic aspects of earthquake prediction are discussed: location of the areas where large earthquakes are most likely to occur, observation within these areas of measurable changes (earthquake precursors) and determination of the area and time over which the earthquake will occur, and development of models of the earthquake source in order to interpret the precursors reliably. 6 figures

Earthquake Culture: A Significant Element in Earthquake Disaster Risk Assessment and Earthquake Disaster Risk Management

OpenAIRE

Ibrion, Mihaela

2018-01-01

This book chapter brings to attention the dramatic impact of large earthquake disasters on local communities and society and highlights the necessity of building and enhancing the earthquake culture. Iran was considered as a research case study and fifteen large earthquake disasters in Iran were investigated and analyzed over more than a century-time period. It was found that the earthquake culture in Iran was and is still conditioned by many factors or parameters which are not integrated and...

Earthquakes and Earthquake Engineering. LC Science Tracer Bullet.

Science.gov (United States)

Buydos, John F., Comp.

An earthquake is a shaking of the ground resulting from a disturbance in the earth's interior. Seismology is the (1) study of earthquakes; (2) origin, propagation, and energy of seismic phenomena; (3) prediction of these phenomena; and (4) investigation of the structure of the earth. Earthquake engineering or engineering seismology includes the…

Analog earthquakes

International Nuclear Information System (INIS)

Hofmann, R.B.

1995-01-01

Analogs are used to understand complex or poorly understood phenomena for which little data may be available at the actual repository site. Earthquakes are complex phenomena, and they can have a large number of effects on the natural system, as well as on engineered structures. Instrumental data close to the source of large earthquakes are rarely obtained. The rare events for which measurements are available may be used, with modfications, as analogs for potential large earthquakes at sites where no earthquake data are available. In the following, several examples of nuclear reactor and liquified natural gas facility siting are discussed. A potential use of analog earthquakes is proposed for a high-level nuclear waste (HLW) repository

Turkish Compulsory Earthquake Insurance and "Istanbul Earthquake

Science.gov (United States)

Durukal, E.; Sesetyan, K.; Erdik, M.

2009-04-01

The city of Istanbul will likely experience substantial direct and indirect losses as a result of a future large (M=7+) earthquake with an annual probability of occurrence of about 2%. This paper dwells on the expected building losses in terms of probable maximum and average annualized losses and discusses the results from the perspective of the compulsory earthquake insurance scheme operational in the country. The TCIP system is essentially designed to operate in Turkey with sufficient penetration to enable the accumulation of funds in the pool. Today, with only 20% national penetration, and about approximately one-half of all policies in highly earthquake prone areas (one-third in Istanbul) the system exhibits signs of adverse selection, inadequate premium structure and insufficient funding. Our findings indicate that the national compulsory earthquake insurance pool in Turkey will face difficulties in covering incurring building losses in Istanbul in the occurrence of a large earthquake. The annualized earthquake losses in Istanbul are between 140-300 million. Even if we assume that the deductible is raised to 15%, the earthquake losses that need to be paid after a large earthquake in Istanbul will be at about 2.5 Billion, somewhat above the current capacity of the TCIP. Thus, a modification to the system for the insured in Istanbul (or Marmara region) is necessary. This may mean an increase in the premia and deductible rates, purchase of larger re-insurance covers and development of a claim processing system. Also, to avoid adverse selection, the penetration rates elsewhere in Turkey need to be increased substantially. A better model would be introduction of parametric insurance for Istanbul. By such a model the losses will not be indemnified, however will be directly calculated on the basis of indexed ground motion levels and damages. The immediate improvement of a parametric insurance model over the existing one will be the elimination of the claim processing

Earthquake potential revealed by tidal influence on earthquake size-frequency statistics

Science.gov (United States)

Ide, Satoshi; Yabe, Suguru; Tanaka, Yoshiyuki

2016-11-01

The possibility that tidal stress can trigger earthquakes is long debated. In particular, a clear causal relationship between small earthquakes and the phase of tidal stress is elusive. However, tectonic tremors deep within subduction zones are highly sensitive to tidal stress levels, with tremor rate increasing at an exponential rate with rising tidal stress. Thus, slow deformation and the possibility of earthquakes at subduction plate boundaries may be enhanced during periods of large tidal stress. Here we calculate the tidal stress history, and specifically the amplitude of tidal stress, on a fault plane in the two weeks before large earthquakes globally, based on data from the global, Japanese, and Californian earthquake catalogues. We find that very large earthquakes, including the 2004 Sumatran, 2010 Maule earthquake in Chile and the 2011 Tohoku-Oki earthquake in Japan, tend to occur near the time of maximum tidal stress amplitude. This tendency is not obvious for small earthquakes. However, we also find that the fraction of large earthquakes increases (the b-value of the Gutenberg-Richter relation decreases) as the amplitude of tidal shear stress increases. The relationship is also reasonable, considering the well-known relationship between stress and the b-value. This suggests that the probability of a tiny rock failure expanding to a gigantic rupture increases with increasing tidal stress levels. We conclude that large earthquakes are more probable during periods of high tidal stress.

Earthquake, GIS and multimedia. The 1883 Casamicciola earthquake

Directory of Open Access Journals (Sweden)

M. Rebuffat

1995-06-01

Full Text Available A series of multimedia monographs concerning the main seismic events that have affected the Italian territory are in the process of being produced for the Documental Integrated Multimedia Project (DIMP started by the Italian National Seismic Survey (NSS. The purpose of the project is to reconstruct the historical record of earthquakes and promote an earthquake public education. Producing the monographs. developed in ARC INFO and working in UNIX. involved designing a special filing and management methodology to integrate heterogeneous information (images, papers, cartographies, etc.. This paper describes the possibilities of a GIS (Geographic Information System in the filing and management of documental information. As an example we present the first monograph on the 1883 Casamicciola earthquake. on the island of Ischia (Campania, Italy. This earthquake is particularly interesting for the following reasons: I historical-cultural context (first destructive seismic event after the unification of Italy; 2 its features (volcanic earthquake; 3 the socioeconomic consequences caused at such an important seaside resort.

OMG Earthquake! Can Twitter improve earthquake response?

Science.gov (United States)

Earle, P. S.; Guy, M.; Ostrum, C.; Horvath, S.; Buckmaster, R. A.

2009-12-01

The U.S. Geological Survey (USGS) is investigating how the social networking site Twitter, a popular service for sending and receiving short, public, text messages, can augment its earthquake response products and the delivery of hazard information. The goal is to gather near real-time, earthquake-related messages (tweets) and provide geo-located earthquake detections and rough maps of the corresponding felt areas. Twitter and other social Internet technologies are providing the general public with anecdotal earthquake hazard information before scientific information has been published from authoritative sources. People local to an event often publish information within seconds via these technologies. In contrast, depending on the location of the earthquake, scientific alerts take between 2 to 20 minutes. Examining the tweets following the March 30, 2009, M4.3 Morgan Hill earthquake shows it is possible (in some cases) to rapidly detect and map the felt area of an earthquake using Twitter responses. Within a minute of the earthquake, the frequency of “earthquake” tweets rose above the background level of less than 1 per hour to about 150 per minute. Using the tweets submitted in the first minute, a rough map of the felt area can be obtained by plotting the tweet locations. Mapping the tweets from the first six minutes shows observations extending from Monterey to Sacramento, similar to the perceived shaking region mapped by the USGS “Did You Feel It” system. The tweets submitted after the earthquake also provided (very) short first-impression narratives from people who experienced the shaking. Accurately assessing the potential and robustness of a Twitter-based system is difficult because only tweets spanning the previous seven days can be searched, making a historical study impossible. We have, however, been archiving tweets for several months, and it is clear that significant limitations do exist. The main drawback is the lack of quantitative information

Earthquake Early Warning Systems

OpenAIRE

Pei-Yang Lin

2011-01-01

Because of Taiwan’s unique geographical environment, earthquake disasters occur frequently in Taiwan. The Central Weather Bureau collated earthquake data from between 1901 and 2006 (Central Weather Bureau, 2007) and found that 97 earthquakes had occurred, of which, 52 resulted in casualties. The 921 Chichi Earthquake had the most profound impact. Because earthquakes have instant destructive power and current scientific technologies cannot provide precise early warnings in advance, earthquake ...

Twitter earthquake detection: Earthquake monitoring in a social world

Science.gov (United States)

Earle, Paul S.; Bowden, Daniel C.; Guy, Michelle R.

2011-01-01

The U.S. Geological Survey (USGS) is investigating how the social networking site Twitter, a popular service for sending and receiving short, public text messages, can augment USGS earthquake response products and the delivery of hazard information. Rapid detection and qualitative assessment of shaking events are possible because people begin sending public Twitter messages (tweets) with in tens of seconds after feeling shaking. Here we present and evaluate an earthquake detection procedure that relies solely on Twitter data. A tweet-frequency time series constructed from tweets containing the word "earthquake" clearly shows large peaks correlated with the origin times of widely felt events. To identify possible earthquakes, we use a short-term-average, long-term-average algorithm. When tuned to a moderate sensitivity, the detector finds 48 globally-distributed earthquakes with only two false triggers in five months of data. The number of detections is small compared to the 5,175 earthquakes in the USGS global earthquake catalog for the same five-month time period, and no accurate location or magnitude can be assigned based on tweet data alone. However, Twitter earthquake detections are not without merit. The detections are generally caused by widely felt events that are of more immediate interest than those with no human impact. The detections are also fast; about 75% occur within two minutes of the origin time. This is considerably faster than seismographic detections in poorly instrumented regions of the world. The tweets triggering the detections also provided very short first-impression narratives from people who experienced the shaking.

Ground water and earthquakes

Energy Technology Data Exchange (ETDEWEB)

Ts' ai, T H

1977-11-01

Chinese folk wisdom has long seen a relationship between ground water and earthquakes. Before an earthquake there is often an unusual change in the ground water level and volume of flow. Changes in the amount of particulate matter in ground water as well as changes in color, bubbling, gas emission, and noises and geysers are also often observed before earthquakes. Analysis of these features can help predict earthquakes. Other factors unrelated to earthquakes can cause some of these changes, too. As a first step it is necessary to find sites which are sensitive to changes in ground stress to be used as sensor points for predicting earthquakes. The necessary features are described. Recording of seismic waves of earthquake aftershocks is also an important part of earthquake predictions.

Foreshocks, aftershocks, and earthquake probabilities: Accounting for the landers earthquake

Science.gov (United States)

Jones, Lucile M.

1994-01-01

The equation to determine the probability that an earthquake occurring near a major fault will be a foreshock to a mainshock on that fault is modified to include the case of aftershocks to a previous earthquake occurring near the fault. The addition of aftershocks to the background seismicity makes its less probable that an earthquake will be a foreshock, because nonforeshocks have become more common. As the aftershocks decay with time, the probability that an earthquake will be a foreshock increases. However, fault interactions between the first mainshock and the major fault can increase the long-term probability of a characteristic earthquake on that fault, which will, in turn, increase the probability that an event is a foreshock, compensating for the decrease caused by the aftershocks.

Earthquake forecasting and warning

Energy Technology Data Exchange (ETDEWEB)

Rikitake, T.

1983-01-01

This review briefly describes two other books on the same subject either written or partially written by Rikitake. In this book, the status of earthquake prediction efforts in Japan, China, the Soviet Union, and the United States are updated. An overview of some of the organizational, legal, and societal aspects of earthquake prediction in these countries is presented, and scientific findings of precursory phenomena are included. A summary of circumstances surrounding the 1975 Haicheng earthquake, the 1978 Tangshan earthquake, and the 1976 Songpan-Pingwu earthquake (all magnitudes = 7.0) in China and the 1978 Izu-Oshima earthquake in Japan is presented. This book fails to comprehensively summarize recent advances in earthquake prediction research.

Ionospheric earthquake precursors

International Nuclear Information System (INIS)

Bulachenko, A.L.; Oraevskij, V.N.; Pokhotelov, O.A.; Sorokin, V.N.; Strakhov, V.N.; Chmyrev, V.M.

1996-01-01

Results of experimental study on ionospheric earthquake precursors, program development on processes in the earthquake focus and physical mechanisms of formation of various type precursors are considered. Composition of experimental cosmic system for earthquake precursors monitoring is determined. 36 refs., 5 figs

Comparison of two large earthquakes: the 2008 Sichuan Earthquake and the 2011 East Japan Earthquake.

Science.gov (United States)

Otani, Yuki; Ando, Takayuki; Atobe, Kaori; Haiden, Akina; Kao, Sheng-Yuan; Saito, Kohei; Shimanuki, Marie; Yoshimoto, Norifumi; Fukunaga, Koichi

2012-01-01

Between August 15th and 19th, 2011, eight 5th-year medical students from the Keio University School of Medicine had the opportunity to visit the Peking University School of Medicine and hold a discussion session titled "What is the most effective way to educate people for survival in an acute disaster situation (before the mental health care stage)?" During the session, we discussed the following six points: basic information regarding the Sichuan Earthquake and the East Japan Earthquake, differences in preparedness for earthquakes, government actions, acceptance of medical rescue teams, earthquake-induced secondary effects, and media restrictions. Although comparison of the two earthquakes was not simple, we concluded that three major points should be emphasized to facilitate the most effective course of disaster planning and action. First, all relevant agencies should formulate emergency plans and should supply information regarding the emergency to the general public and health professionals on a normal basis. Second, each citizen should be educated and trained in how to minimize the risks from earthquake-induced secondary effects. Finally, the central government should establish a single headquarters responsible for command, control, and coordination during a natural disaster emergency and should centralize all powers in this single authority. We hope this discussion may be of some use in future natural disasters in China, Japan, and worldwide.

Twitter earthquake detection: earthquake monitoring in a social world

Directory of Open Access Journals (Sweden)

Daniel C. Bowden

2011-06-01

Full Text Available The U.S. Geological Survey (USGS is investigating how the social networking site Twitter, a popular service for sending and receiving short, public text messages, can augment USGS earthquake response products and the delivery of hazard information. Rapid detection and qualitative assessment of shaking events are possible because people begin sending public Twitter messages (tweets with in tens of seconds after feeling shaking. Here we present and evaluate an earthquake detection procedure that relies solely on Twitter data. A tweet-frequency time series constructed from tweets containing the word “earthquake” clearly shows large peaks correlated with the origin times of widely felt events. To identify possible earthquakes, we use a short-term-average, long-term-average algorithm. When tuned to a moderate sensitivity, the detector finds 48 globally-distributed earthquakes with only two false triggers in five months of data. The number of detections is small compared to the 5,175 earthquakes in the USGS global earthquake catalog for the same five-month time period, and no accurate location or magnitude can be assigned based on tweet data alone. However, Twitter earthquake detections are not without merit. The detections are generally caused by widely felt events that are of more immediate interest than those with no human impact. The detections are also fast; about 75% occur within two minutes of the origin time. This is considerably faster than seismographic detections in poorly instrumented regions of the world. The tweets triggering the detections also provided very short first-impression narratives from people who experienced the shaking.

Results of the Regional Earthquake Likelihood Models (RELM) test of earthquake forecasts in California.

Science.gov (United States)

Lee, Ya-Ting; Turcotte, Donald L; Holliday, James R; Sachs, Michael K; Rundle, John B; Chen, Chien-Chih; Tiampo, Kristy F

2011-10-04

The Regional Earthquake Likelihood Models (RELM) test of earthquake forecasts in California was the first competitive evaluation of forecasts of future earthquake occurrence. Participants submitted expected probabilities of occurrence of M ≥ 4.95 earthquakes in 0.1° × 0.1° cells for the period 1 January 1, 2006, to December 31, 2010. Probabilities were submitted for 7,682 cells in California and adjacent regions. During this period, 31 M ≥ 4.95 earthquakes occurred in the test region. These earthquakes occurred in 22 test cells. This seismic activity was dominated by earthquakes associated with the M = 7.2, April 4, 2010, El Mayor-Cucapah earthquake in northern Mexico. This earthquake occurred in the test region, and 16 of the other 30 earthquakes in the test region could be associated with it. Nine complete forecasts were submitted by six participants. In this paper, we present the forecasts in a way that allows the reader to evaluate which forecast is the most "successful" in terms of the locations of future earthquakes. We conclude that the RELM test was a success and suggest ways in which the results can be used to improve future forecasts.

Earthquakes, September-October 1986

Science.gov (United States)

Person, W.J.

1987-01-01

There was one great earthquake (8.0 and above) during this reporting period in the South Pacific in the Kermadec Islands. There were no major earthquakes (7.0-7.9) but earthquake-related deaths were reported in Greece and in El Salvador. There were no destrcutive earthquakes in the United States.

EARTHQUAKE-INDUCED DEFORMATION STRUCTURES AND RELATED TO EARTHQUAKE MAGNITUDES

Directory of Open Access Journals (Sweden)

Savaş TOPAL

2003-02-01

Full Text Available Earthquake-induced deformation structures which are called seismites may helpful to clasify the paleoseismic history of a location and to estimate the magnitudes of the potention earthquakes in the future. In this paper, seismites were investigated according to the types formed in deep and shallow lake sediments. Seismites are observed forms of sand dikes, introduced and fractured gravels and pillow structures in shallow lakes and pseudonodules, mushroom-like silts protruding laminites, mixed layers, disturbed varved lamination and loop bedding in deep lake sediments. Earthquake-induced deformation structures, by benefiting from previous studies, were ordered according to their formations and earthquake magnitudes. In this order, the lowest eartquake's record is loop bedding and the highest one is introduced and fractured gravels in lacustrine deposits.

Megathrust earthquakes in Central Chile: What is next after the Maule 2010 earthquake?

Science.gov (United States)

Madariaga, R.

2013-05-01

The 27 February 2010 Maule earthquake occurred in a well identified gap in the Chilean subduction zone. The event has now been studied in detail using both far-field, near field seismic and geodetic data, we will review this information gathered so far. The event broke a region that was much longer along strike than the gap left over from the 1835 Concepcion earthquake, sometimes called the Darwin earthquake because he was in the area when the earthquake occurred and made many observations. Recent studies of contemporary documents by Udias et al indicate that the area broken by the Maule earthquake in 2010 had previously broken by a similar earthquake in 1751, but several events in the magnitude 8 range occurred in the area principally in 1835 already mentioned and, more recently on 1 December 1928 to the North and on 21 May 1960 (1 1/2 days before the big Chilean earthquake of 1960). Currently the area of the 2010 earthquake and the region immediately to the North is undergoing a very large increase in seismicity with numerous clusters of seismicity that move along the plate interface. Examination of the seismicity of Chile of the 18th and 19th century show that the region immediately to the North of the 2010 earthquake broke in a very large megathrust event in July 1730. this is the largest known earthquake in central Chile. The region where this event occurred has broken in many occasions with M 8 range earthquakes in 1822, 1880, 1906, 1971 and 1985. Is it preparing for a new very large megathrust event? The 1906 earthquake of Mw 8.3 filled the central part of the gap but it has broken again on several occasions in 1971, 1973 and 1985. The main question is whether the 1906 earthquake relieved enough stresses from the 1730 rupture zone. Geodetic data shows that most of the region that broke in 1730 is currently almost fully locked from the northern end of the Maule earthquake at 34.5°S to 30°S, near the southern end of the of the Mw 8.5 Atacama earthquake of 11

Extreme value statistics and thermodynamics of earthquakes. Large earthquakes

Energy Technology Data Exchange (ETDEWEB)

Lavenda, B. [Camerino Univ., Camerino, MC (Italy); Cipollone, E. [ENEA, Centro Ricerche Casaccia, S. Maria di Galeria, RM (Italy). National Centre for Research on Thermodynamics

2000-06-01

A compound Poisson process is used to derive a new shape parameter which can be used to discriminate between large earthquakes and aftershocks sequences. Sample exceedance distributions of large earthquakes are fitted to the Pareto tail and the actual distribution of the maximum to the Frechet distribution, while the sample distribution of aftershocks are fitted to a Beta distribution and the distribution of the minimum to the Weibull distribution for the smallest value. The transition between initial sample distributions and asymptotic extreme value distributions show that self-similar power laws are transformed into non scaling exponential distributions so that neither self-similarity nor the Gutenberg-Richter law can be considered universal. The energy-magnitude transformation converts the Frechet distribution into the Gumbel distribution, originally proposed by Epstein and Lomnitz, and not the Gompertz distribution as in the Lomnitz-Adler and Lomnitz generalization of the Gutenberg-Richter law. Numerical comparison is made with the Lomnitz-Adler and Lomnitz analysis using the same catalogue of Chinese earthquakes. An analogy is drawn between large earthquakes and high energy particle physics. A generalized equation of state is used to transform the Gamma density into the order-statistic Frechet distribution. Earthquake temperature and volume are determined as functions of the energy. Large insurance claims based on the Pareto distribution, which does not have a right endpoint, show why there cannot be a maximum earthquake energy.

The GIS and analysis of earthquake damage distribution of the 1303 Hongtong M=8 earthquake

Science.gov (United States)

Gao, Meng-Tan; Jin, Xue-Shen; An, Wei-Ping; Lü, Xiao-Jian

2004-07-01

The geography information system of the 1303 Hongton M=8 earthquake has been established. Using the spatial analysis function of GIS, the spatial distribution characteristics of damage and isoseismal of the earthquake are studies. By comparing with the standard earthquake intensity attenuation relationship, the abnormal damage distribution of the earthquake is found, so the relationship of the abnormal distribution with tectonics, site condition and basin are analyzed. In this paper, the influence on the ground motion generated by earthquake source and the underground structures near source also are studied. The influence on seismic zonation, anti-earthquake design, earthquake prediction and earthquake emergency responding produced by the abnormal density distribution are discussed.

Earthquakes, November-December 1977

Science.gov (United States)

Person, W.J.

1978-01-01

Two major earthquakes occurred in the last 2 months of the year. A magnitude 7.0 earthquake struck San Juan Province, Argentina, on November 23, causing fatalities and damage. The second major earthquake was a magnitude 7.0 in the Bonin Islands region, an unpopulated area. On December 19, Iran experienced a destructive earthquake, which killed over 500.

Protecting your family from earthquakes: The seven steps to earthquake safety

Science.gov (United States)

Developed by American Red Cross, Asian Pacific Fund

2007-01-01

This book is provided here because of the importance of preparing for earthquakes before they happen. Experts say it is very likely there will be a damaging San Francisco Bay Area earthquake in the next 30 years and that it will strike without warning. It may be hard to find the supplies and services we need after this earthquake. For example, hospitals may have more patients than they can treat, and grocery stores may be closed for weeks. You will need to provide for your family until help arrives. To keep our loved ones and our community safe, we must prepare now. Some of us come from places where earthquakes are also common. However, the dangers of earthquakes in our homelands may be very different than in the Bay Area. For example, many people in Asian countries die in major earthquakes when buildings collapse or from big sea waves called tsunami. In the Bay Area, the main danger is from objects inside buildings falling on people. Take action now to make sure your family will be safe in an earthquake. The first step is to read this book carefully and follow its advice. By making your home safer, you help make our community safer. Preparing for earthquakes is important, and together we can make sure our families and community are ready. English version p. 3-13 Chinese version p. 14-24 Vietnamese version p. 25-36 Korean version p. 37-48

Earthquake Triggering in the September 2017 Mexican Earthquake Sequence

Science.gov (United States)

Fielding, E. J.; Gombert, B.; Duputel, Z.; Huang, M. H.; Liang, C.; Bekaert, D. P.; Moore, A. W.; Liu, Z.; Ampuero, J. P.

2017-12-01

Southern Mexico was struck by four earthquakes with Mw > 6 and numerous smaller earthquakes in September 2017, starting with the 8 September Mw 8.2 Tehuantepec earthquake beneath the Gulf of Tehuantepec offshore Chiapas and Oaxaca. We study whether this M8.2 earthquake triggered the three subsequent large M>6 quakes in southern Mexico to improve understanding of earthquake interactions and time-dependent risk. All four large earthquakes were extensional despite the the subduction of the Cocos plate. The traditional definition of aftershocks: likely an aftershock if it occurs within two rupture lengths of the main shock soon afterwards. Two Mw 6.1 earthquakes, one half an hour after the M8.2 beneath the Tehuantepec gulf and one on 23 September near Ixtepec in Oaxaca, both fit as traditional aftershocks, within 200 km of the main rupture. The 19 September Mw 7.1 Puebla earthquake was 600 km away from the M8.2 shock, outside the standard aftershock zone. Geodetic measurements from interferometric analysis of synthetic aperture radar (InSAR) and time-series analysis of GPS station data constrain finite fault total slip models for the M8.2, M7.1, and M6.1 Ixtepec earthquakes. The early M6.1 aftershock was too close in time and space to the M8.2 to measure with InSAR or GPS. We analyzed InSAR data from Copernicus Sentinel-1A and -1B satellites and JAXA ALOS-2 satellite. Our preliminary geodetic slip model for the M8.2 quake shows significant slip extended > 150 km NW from the hypocenter, longer than slip in the v1 finite-fault model (FFM) from teleseismic waveforms posted by G. Hayes at USGS NEIC. Our slip model for the M7.1 earthquake is similar to the v2 NEIC FFM. Interferograms for the M6.1 Ixtepec quake confirm the shallow depth in the upper-plate crust and show centroid is about 30 km SW of the NEIC epicenter, a significant NEIC location bias, but consistent with cluster relocations (E. Bergman, pers. comm.) and with Mexican SSN location. Coulomb static stress

Evidence for strong Holocene earthquake(s) in the Wabash Valley seismic zone

International Nuclear Information System (INIS)

Obermeier, S.

1991-01-01

Many small and slightly damaging earthquakes have taken place in the region of the lower Wabash River Valley of Indiana and Illinois during the 200 years of historic record. Seismologists have long suspected the Wabash Valley seismic zone to be capable of producing earthquakes much stronger than the largest of record (m b 5.8). The seismic zone contains the poorly defined Wabash Valley fault zone and also appears to contain other vaguely defined faults at depths from which the strongest earthquakes presently originate. Faults near the surface are generally covered with thick alluvium in lowlands and a veneer of loess in uplands, which make direct observations of faults difficult. Partly because of this difficulty, a search for paleoliquefaction features was begun in 1990. Conclusions of the study are as follows: (1) an earthquake much stronger than any historic earthquake struck the lower Wabash Valley between 1,500 and 7,500 years ago; (2) the epicentral region of the prehistoric strong earthquake was the Wabash Valley seismic zone; (3) apparent sites have been located where 1811-12 earthquake accelerations can be bracketed

The 1985 central chile earthquake: a repeat of previous great earthquakes in the region?

Science.gov (United States)

Comte, D; Eisenberg, A; Lorca, E; Pardo, M; Ponce, L; Saragoni, R; Singh, S K; Suárez, G

1986-07-25

A great earthquake (surface-wave magnitude, 7.8) occurred along the coast of central Chile on 3 March 1985, causing heavy damage to coastal towns. Intense foreshock activity near the epicenter of the main shock occurred for 11 days before the earthquake. The aftershocks of the 1985 earthquake define a rupture area of 170 by 110 square kilometers. The earthquake was forecast on the basis of the nearly constant repeat time (83 +/- 9 years) of great earthquakes in this region. An analysis of previous earthquakes suggests that the rupture lengths of great shocks in the region vary by a factor of about 3. The nearly constant repeat time and variable rupture lengths cannot be reconciled with time- or slip-predictable models of earthquake recurrence. The great earthquakes in the region seem to involve a variable rupture mode and yet, for unknown reasons, remain periodic. Historical data suggest that the region south of the 1985 rupture zone should now be considered a gap of high seismic potential that may rupture in a great earthquake in the next few tens of years.

The relationship between earthquake exposure and posttraumatic stress disorder in 2013 Lushan earthquake

Science.gov (United States)

Wang, Yan; Lu, Yi

2018-01-01

The objective of this study is to explore the relationship between earthquake exposure and the incidence of PTSD. A stratification random sample survey was conducted to collect data in the Longmenshan thrust fault after Lushan earthquake three years. We used the Children's Revised Impact of Event Scale (CRIES-13) and the Earthquake Experience Scale. Subjects in this study included 3944 school student survivors in local eleven schools. The prevalence of probable PTSD is relatively higher, when the people was trapped in the earthquake, was injured in the earthquake or have relatives who died in the earthquake. It concluded that researchers need to pay more attention to the children and adolescents. The government should pay more attention to these people and provide more economic support.

Crowdsourced earthquake early warning

Science.gov (United States)

Minson, Sarah E.; Brooks, Benjamin A.; Glennie, Craig L.; Murray, Jessica R.; Langbein, John O.; Owen, Susan E.; Heaton, Thomas H.; Iannucci, Robert A.; Hauser, Darren L.

2015-01-01

Earthquake early warning (EEW) can reduce harm to people and infrastructure from earthquakes and tsunamis, but it has not been implemented in most high earthquake-risk regions because of prohibitive cost. Common consumer devices such as smartphones contain low-cost versions of the sensors used in EEW. Although less accurate than scientific-grade instruments, these sensors are globally ubiquitous. Through controlled tests of consumer devices, simulation of an Mw (moment magnitude) 7 earthquake on California’s Hayward fault, and real data from the Mw 9 Tohoku-oki earthquake, we demonstrate that EEW could be achieved via crowdsourcing.

Encyclopedia of earthquake engineering

CERN Document Server

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

2015-01-01

The Encyclopedia of Earthquake Engineering is designed to be the authoritative and comprehensive reference covering all major aspects of the science of earthquake engineering, specifically focusing on the interaction between earthquakes and infrastructure. The encyclopedia comprises approximately 265 contributions. Since earthquake engineering deals with the interaction between earthquake disturbances and the built infrastructure, the emphasis is on basic design processes important to both non-specialists and engineers so that readers become suitably well-informed without needing to deal with the details of specialist understanding. The content of this encyclopedia provides technically inclined and informed readers about the ways in which earthquakes can affect our infrastructure and how engineers would go about designing against, mitigating and remediating these effects. The coverage ranges from buildings, foundations, underground construction, lifelines and bridges, roads, embankments and slopes. The encycl...

Earthquake hazard evaluation for Switzerland

International Nuclear Information System (INIS)

Ruettener, E.

1995-01-01

Earthquake hazard analysis is of considerable importance for Switzerland, a country with moderate seismic activity but high economic values at risk. The evaluation of earthquake hazard, i.e. the determination of return periods versus ground motion parameters, requires a description of earthquake occurrences in space and time. In this study the seismic hazard for major cities in Switzerland is determined. The seismic hazard analysis is based on historic earthquake records as well as instrumental data. The historic earthquake data show considerable uncertainties concerning epicenter location and epicentral intensity. A specific concept is required, therefore, which permits the description of the uncertainties of each individual earthquake. This is achieved by probability distributions for earthquake size and location. Historical considerations, which indicate changes in public earthquake awareness at various times (mainly due to large historical earthquakes), as well as statistical tests have been used to identify time periods of complete earthquake reporting as a function of intensity. As a result, the catalog is judged to be complete since 1878 for all earthquakes with epicentral intensities greater than IV, since 1750 for intensities greater than VI, since 1600 for intensities greater than VIII, and since 1300 for intensities greater than IX. Instrumental data provide accurate information about the depth distribution of earthquakes in Switzerland. In the Alps, focal depths are restricted to the uppermost 15 km of the crust, whereas below the northern Alpine foreland earthquakes are distributed throughout the entire crust (30 km). This depth distribution is considered in the final hazard analysis by probability distributions. (author) figs., tabs., refs

Earthquake Clusters and Spatio-temporal Migration of earthquakes in Northeastern Tibetan Plateau: a Finite Element Modeling

Science.gov (United States)

Sun, Y.; Luo, G.

2017-12-01

Seismicity in a region is usually characterized by earthquake clusters and earthquake migration along its major fault zones. However, we do not fully understand why and how earthquake clusters and spatio-temporal migration of earthquakes occur. The northeastern Tibetan Plateau is a good example for us to investigate these problems. In this study, we construct and use a three-dimensional viscoelastoplastic finite-element model to simulate earthquake cycles and spatio-temporal migration of earthquakes along major fault zones in northeastern Tibetan Plateau. We calculate stress evolution and fault interactions, and explore effects of topographic loading and viscosity of middle-lower crust and upper mantle on model results. Model results show that earthquakes and fault interactions increase Coulomb stress on the neighboring faults or segments, accelerating the future earthquakes in this region. Thus, earthquakes occur sequentially in a short time, leading to regional earthquake clusters. Through long-term evolution, stresses on some seismogenic faults, which are far apart, may almost simultaneously reach the critical state of fault failure, probably also leading to regional earthquake clusters and earthquake migration. Based on our model synthetic seismic catalog and paleoseismic data, we analyze probability of earthquake migration between major faults in northeastern Tibetan Plateau. We find that following the 1920 M 8.5 Haiyuan earthquake and the 1927 M 8.0 Gulang earthquake, the next big event (M≥7) in northeastern Tibetan Plateau would be most likely to occur on the Haiyuan fault.

Perception of earthquake risk in Taiwan: effects of gender and past earthquake experience.

Science.gov (United States)

Kung, Yi-Wen; Chen, Sue-Huei

2012-09-01

This study explored how individuals in Taiwan perceive the risk of earthquake and the relationship of past earthquake experience and gender to risk perception. Participants (n= 1,405), including earthquake survivors and those in the general population without prior direct earthquake exposure, were selected and interviewed through a computer-assisted telephone interviewing procedure using a random sampling and stratification method covering all 24 regions of Taiwan. A factor analysis of the interview data yielded a two-factor structure of risk perception in regard to earthquake. The first factor, "personal impact," encompassed perception of threat and fear related to earthquakes. The second factor, "controllability," encompassed a sense of efficacy of self-protection in regard to earthquakes. The findings indicated prior earthquake survivors and females reported higher scores on the personal impact factor than males and those with no prior direct earthquake experience, although there were no group differences on the controllability factor. The findings support that risk perception has multiple components, and suggest that past experience (survivor status) and gender (female) affect the perception of risk. Exploration of potential contributions of other demographic factors such as age, education, and marital status to personal impact, especially for females and survivors, is discussed. Future research on and intervention program with regard to risk perception are suggested accordingly. © 2012 Society for Risk Analysis.

The earthquake problem in engineering design: generating earthquake design basis information

International Nuclear Information System (INIS)

Sharma, R.D.

1987-01-01

Designing earthquake resistant structures requires certain design inputs specific to the seismotectonic status of the region, in which a critical facility is to be located. Generating these inputs requires collection of earthquake related information using present day techniques in seismology and geology, and processing the collected information to integrate it to arrive at a consolidated picture of the seismotectonics of the region. The earthquake problem in engineering design has been outlined in the context of a seismic design of nuclear power plants vis a vis current state of the art techniques. The extent to which the accepted procedures of assessing seismic risk in the region and generating the design inputs have been adherred to determine to a great extent the safety of the structures against future earthquakes. The document is a step towards developing an aproach for generating these inputs, which form the earthquake design basis. (author)

Limitation of the Predominant-Period Estimator for Earthquake Early Warning and the Initial Rupture of Earthquakes

Science.gov (United States)

Yamada, T.; Ide, S.

2007-12-01

Earthquake early warning is an important and challenging issue for the reduction of the seismic damage, especially for the mitigation of human suffering. One of the most important problems in earthquake early warning systems is how immediately we can estimate the final size of an earthquake after we observe the ground motion. It is relevant to the problem whether the initial rupture of an earthquake has some information associated with its final size. Nakamura (1988) developed the Urgent Earthquake Detection and Alarm System (UrEDAS). It calculates the predominant period of the P wave (τp) and estimates the magnitude of an earthquake immediately after the P wave arrival from the value of τpmax, or the maximum value of τp. The similar approach has been adapted by other earthquake alarm systems (e.g., Allen and Kanamori (2003)). To investigate the characteristic of the parameter τp and the effect of the length of the time window (TW) in the τpmax calculation, we analyze the high-frequency recordings of earthquakes at very close distances in the Mponeng mine in South Africa. We find that values of τpmax have upper and lower limits. For larger earthquakes whose source durations are longer than TW, the values of τpmax have an upper limit which depends on TW. On the other hand, the values for smaller earthquakes have a lower limit which is proportional to the sampling interval. For intermediate earthquakes, the values of τpmax are close to their typical source durations. These two limits and the slope for intermediate earthquakes yield an artificial final size dependence of τpmax in a wide size range. The parameter τpmax is useful for detecting large earthquakes and broadcasting earthquake early warnings. However, its dependence on the final size of earthquakes does not suggest that the earthquake rupture is deterministic. This is because τpmax does not always have a direct relation to the physical quantities of an earthquake.

Sun, Moon and Earthquakes

Science.gov (United States)

Kolvankar, V. G.

2013-12-01

During a study conducted to find the effect of Earth tides on the occurrence of earthquakes, for small areas [typically 1000km X1000km] of high-seismicity regions, it was noticed that the Sun's position in terms of universal time [GMT] shows links to the sum of EMD [longitude of earthquake location - longitude of Moon's foot print on earth] and SEM [Sun-Earth-Moon angle]. This paper provides the details of this relationship after studying earthquake data for over forty high-seismicity regions of the world. It was found that over 98% of the earthquakes for these different regions, examined for the period 1973-2008, show a direct relationship between the Sun's position [GMT] and [EMD+SEM]. As the time changes from 00-24 hours, the factor [EMD+SEM] changes through 360 degree, and plotting these two variables for earthquakes from different small regions reveals a simple 45 degree straight-line relationship between them. This relationship was tested for all earthquakes and earthquake sequences for magnitude 2.0 and above. This study conclusively proves how Sun and the Moon govern all earthquakes. Fig. 12 [A+B]. The left-hand figure provides a 24-hour plot for forty consecutive days including the main event (00:58:23 on 26.12.2004, Lat.+3.30, Long+95.980, Mb 9.0, EQ count 376). The right-hand figure provides an earthquake plot for (EMD+SEM) vs GMT timings for the same data. All the 376 events including the main event faithfully follow the straight-line curve.

Earthquake engineering development before and after the March 4, 1977, Vrancea, Romania earthquake

International Nuclear Information System (INIS)

Georgescu, E.-S.

2002-01-01

At 25 years since the of the Vrancea earthquake of March, 4th 1977, we can analyze in an open and critical way its impact on the evolution of earthquake engineering codes and protection policies in Romania. The earthquake (M G-R = 7.2; M w = 7.5), produced 1,570 casualties and more than 11,300 injured persons (90% of the victims in Bucharest), seismic losses were estimated at more then USD 2 billions. The 1977 earthquake represented a significant episode of XXth century in seismic zones of Romania and neighboring countries. The INCERC seismic record of March 4, 1977 put, for the first time, in evidence the spectral content of long period seismic motions of Vrancea earthquakes, the duration, the number of cycles and values of actual accelerations, with important effects of overloading upon flexible structures. The seismic coefficients k s , the spectral curve (the dynamic coefficient β r ) and the seismic zonation map, the requirements in the antiseismic design norms were drastically, changed while the microzonation maps of the time ceased to be used, and the specific Vrancea earthquake recurrence was reconsidered based on hazard studies Thus, the paper emphasises: - the existing engineering knowledge, earthquake code and zoning maps requirements until 1977 as well as seismology and structural lessons since 1977; - recent aspects of implementing of the Earthquake Code P.100/1992 and harmonization with Eurocodes, in conjunction with the specific of urban and rural seismic risk and enforcing policies on strengthening of existing buildings; - a strategic view of disaster prevention, using earthquake scenarios and loss assessments, insurance, earthquake education and training; - the need of a closer transfer of knowledge between seismologists, engineers and officials in charge with disaster prevention public policies. (author)

The music of earthquakes and Earthquake Quartet #1

Science.gov (United States)

Michael, Andrew J.

2013-01-01

Earthquake Quartet #1, my composition for voice, trombone, cello, and seismograms, is the intersection of listening to earthquakes as a seismologist and performing music as a trombonist. Along the way, I realized there is a close relationship between what I do as a scientist and what I do as a musician. A musician controls the source of the sound and the path it travels through their instrument in order to make sound waves that we hear as music. An earthquake is the source of waves that travel along a path through the earth until reaching us as shaking. It is almost as if the earth is a musician and people, including seismologists, are metaphorically listening and trying to understand what the music means.

Toward real-time regional earthquake simulation of Taiwan earthquakes

Science.gov (United States)

Lee, S.; Liu, Q.; Tromp, J.; Komatitsch, D.; Liang, W.; Huang, B.

2013-12-01

We developed a Real-time Online earthquake Simulation system (ROS) to simulate regional earthquakes in Taiwan. The ROS uses a centroid moment tensor solution of seismic events from a Real-time Moment Tensor monitoring system (RMT), which provides all the point source parameters including the event origin time, hypocentral location, moment magnitude and focal mechanism within 2 minutes after the occurrence of an earthquake. Then, all of the source parameters are automatically forwarded to the ROS to perform an earthquake simulation, which is based on a spectral-element method (SEM). We have improved SEM mesh quality by introducing a thin high-resolution mesh layer near the surface to accommodate steep and rapidly varying topography. The mesh for the shallow sedimentary basin is adjusted to reflect its complex geometry and sharp lateral velocity contrasts. The grid resolution at the surface is about 545 m, which is sufficient to resolve topography and tomography data for simulations accurate up to 1.0 Hz. The ROS is also an infrastructural service, making online earthquake simulation feasible. Users can conduct their own earthquake simulation by providing a set of source parameters through the ROS webpage. For visualization, a ShakeMovie and ShakeMap are produced during the simulation. The time needed for one event is roughly 3 minutes for a 70 sec ground motion simulation. The ROS is operated online at the Institute of Earth Sciences, Academia Sinica (http://ros.earth.sinica.edu.tw/). Our long-term goal for the ROS system is to contribute to public earth science outreach and to realize seismic ground motion prediction in real-time.

Geophysical Anomalies and Earthquake Prediction

Science.gov (United States)

Jackson, D. D.

2008-12-01

Finding anomalies is easy. Predicting earthquakes convincingly from such anomalies is far from easy. Why? Why have so many beautiful geophysical abnormalities not led to successful prediction strategies? What is earthquake prediction? By my definition it is convincing information that an earthquake of specified size is temporarily much more likely than usual in a specific region for a specified time interval. We know a lot about normal earthquake behavior, including locations where earthquake rates are higher than elsewhere, with estimable rates and size distributions. We know that earthquakes have power law size distributions over large areas, that they cluster in time and space, and that aftershocks follow with power-law dependence on time. These relationships justify prudent protective measures and scientific investigation. Earthquake prediction would justify exceptional temporary measures well beyond those normal prudent actions. Convincing earthquake prediction would result from methods that have demonstrated many successes with few false alarms. Predicting earthquakes convincingly is difficult for several profound reasons. First, earthquakes start in tiny volumes at inaccessible depth. The power law size dependence means that tiny unobservable ones are frequent almost everywhere and occasionally grow to larger size. Thus prediction of important earthquakes is not about nucleation, but about identifying the conditions for growth. Second, earthquakes are complex. They derive their energy from stress, which is perniciously hard to estimate or model because it is nearly singular at the margins of cracks and faults. Physical properties vary from place to place, so the preparatory processes certainly vary as well. Thus establishing the needed track record for validation is very difficult, especially for large events with immense interval times in any one location. Third, the anomalies are generally complex as well. Electromagnetic anomalies in particular require

Historical earthquake research in Austria

Science.gov (United States)

Hammerl, Christa

2017-12-01

Austria has a moderate seismicity, and on average the population feels 40 earthquakes per year or approximately three earthquakes per month. A severe earthquake with light building damage is expected roughly every 2 to 3 years in Austria. Severe damage to buildings ( I 0 > 8° EMS) occurs significantly less frequently, the average period of recurrence is about 75 years. For this reason the historical earthquake research has been of special importance in Austria. The interest in historical earthquakes in the past in the Austro-Hungarian Empire is outlined, beginning with an initiative of the Austrian Academy of Sciences and the development of historical earthquake research as an independent research field after the 1978 "Zwentendorf plebiscite" on whether the nuclear power plant will start up. The applied methods are introduced briefly along with the most important studies and last but not least as an example of a recently carried out case study, one of the strongest past earthquakes in Austria, the earthquake of 17 July 1670, is presented. The research into historical earthquakes in Austria concentrates on seismic events of the pre-instrumental period. The investigations are not only of historical interest, but also contribute to the completeness and correctness of the Austrian earthquake catalogue, which is the basis for seismic hazard analysis and as such benefits the public, communities, civil engineers, architects, civil protection, and many others.

Where was the 1898 Mare Island Earthquake? Insights from the 2014 South Napa Earthquake

Science.gov (United States)

Hough, S. E.

2014-12-01

The 2014 South Napa earthquake provides an opportunity to reconsider the Mare Island earthquake of 31 March 1898, which caused severe damage to buildings at a Navy yard on the island. Revising archival accounts of the 1898 earthquake, I estimate a lower intensity magnitude, 5.8, than the value in the current Uniform California Earthquake Rupture Forecast (UCERF) catalog (6.4). However, I note that intensity magnitude can differ from Mw by upwards of half a unit depending on stress drop, which for a historical earthquake is unknowable. In the aftermath of the 2014 earthquake, there has been speculation that apparently severe effects on Mare Island in 1898 were due to the vulnerability of local structures. No surface rupture has ever been identified from the 1898 event, which is commonly associated with the Hayward-Rodgers Creek fault system, some 10 km west of Mare Island (e.g., Parsons et al., 2003). Reconsideration of detailed archival accounts of the 1898 earthquake, together with a comparison of the intensity distributions for the two earthquakes, points to genuinely severe, likely near-field ground motions on Mare Island. The 2014 earthquake did cause significant damage to older brick buildings on Mare Island, but the level of damage does not match the severity of documented damage in 1898. The high intensity files for the two earthquakes are more over spatially shifted, with the centroid of the 2014 distribution near the town of Napa and that of the 1898 distribution near Mare Island, east of the Hayward-Rodgers Creek system. I conclude that the 1898 Mare Island earthquake was centered on or near Mare Island, possibly involving rupture of one or both strands of the Franklin fault, a low-slip-rate fault sub-parallel to the Rodgers Creek fault to the west and the West Napa fault to the east. I estimate Mw5.8 assuming an average stress drop; data are also consistent with Mw6.4 if stress drop was a factor of ≈3 lower than average for California earthquakes. I

Earthquakes, May-June 1991

Science.gov (United States)

Person, W.J.

1992-01-01

One major earthquake occurred during this reporting period. This was a magntidue 7.1 in Indonesia (Minahassa Peninsula) on June 20. Earthquake-related deaths were reported in the Western Caucasus (Georgia, USSR) on May 3 and June 15. One earthquake-related death was also reported El Salvador on June 21. 

Modeling, Forecasting and Mitigating Extreme Earthquakes

Science.gov (United States)

Ismail-Zadeh, A.; Le Mouel, J.; Soloviev, A.

2012-12-01

Recent earthquake disasters highlighted the importance of multi- and trans-disciplinary studies of earthquake risk. A major component of earthquake disaster risk analysis is hazards research, which should cover not only a traditional assessment of ground shaking, but also studies of geodetic, paleoseismic, geomagnetic, hydrological, deep drilling and other geophysical and geological observations together with comprehensive modeling of earthquakes and forecasting extreme events. Extreme earthquakes (large magnitude and rare events) are manifestations of complex behavior of the lithosphere structured as a hierarchical system of blocks of different sizes. Understanding of physics and dynamics of the extreme events comes from observations, measurements and modeling. A quantitative approach to simulate earthquakes in models of fault dynamics will be presented. The models reproduce basic features of the observed seismicity (e.g., the frequency-magnitude relationship, clustering of earthquakes, occurrence of extreme seismic events). They provide a link between geodynamic processes and seismicity, allow studying extreme events, influence of fault network properties on seismic patterns and seismic cycles, and assist, in a broader sense, in earthquake forecast modeling. Some aspects of predictability of large earthquakes (how well can large earthquakes be predicted today?) will be also discussed along with possibilities in mitigation of earthquake disasters (e.g., on 'inverse' forensic investigations of earthquake disasters).

Earthquake Catalogue of the Caucasus

Science.gov (United States)

Godoladze, T.; Gok, R.; Tvaradze, N.; Tumanova, N.; Gunia, I.; Onur, T.

2016-12-01

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; Racha earthquake of 1991 (Ms=7.0), is the largest event ever recorded in the region; Barisakho earthquake of 1992 (M=6.5); Spitak earthquake of 1988 (Ms=6.9, 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 the 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. In order to improve seismic data quality a catalog of all instrumentally recorded earthquakes has been compiled by the IES (Institute of Earth Sciences/NSMC, Ilia State University) in the framework of regional joint project (Armenia, Azerbaijan, Georgia, Turkey, USA) "Probabilistic Seismic Hazard Assessment (PSHA) in the Caucasus. The catalogue consists of more then 80,000 events. First arrivals of each earthquake of Mw>=4.0 have been carefully examined. To reduce calculation errors, we corrected arrivals from the seismic records. We improved locations of the events and recalculate Moment magnitudes in order to obtain unified magnitude

Natural Time and Nowcasting Earthquakes: Are Large Global Earthquakes Temporally Clustered?

Science.gov (United States)

Luginbuhl, Molly; Rundle, John B.; Turcotte, Donald L.

2018-02-01

The objective of this paper is to analyze the temporal clustering of large global earthquakes with respect to natural time, or interevent count, as opposed to regular clock time. To do this, we use two techniques: (1) nowcasting, a new method of statistically classifying seismicity and seismic risk, and (2) time series analysis of interevent counts. We chose the sequences of M_{λ } ≥ 7.0 and M_{λ } ≥ 8.0 earthquakes from the global centroid moment tensor (CMT) catalog from 2004 to 2016 for analysis. A significant number of these earthquakes will be aftershocks of the largest events, but no satisfactory method of declustering the aftershocks in clock time is available. A major advantage of using natural time is that it eliminates the need for declustering aftershocks. The event count we utilize is the number of small earthquakes that occur between large earthquakes. The small earthquake magnitude is chosen to be as small as possible, such that the catalog is still complete based on the Gutenberg-Richter statistics. For the CMT catalog, starting in 2004, we found the completeness magnitude to be M_{σ } ≥ 5.1. For the nowcasting method, the cumulative probability distribution of these interevent counts is obtained. We quantify the distribution using the exponent, β, of the best fitting Weibull distribution; β = 1 for a random (exponential) distribution. We considered 197 earthquakes with M_{λ } ≥ 7.0 and found β = 0.83 ± 0.08. We considered 15 earthquakes with M_{λ } ≥ 8.0, but this number was considered too small to generate a meaningful distribution. For comparison, we generated synthetic catalogs of earthquakes that occur randomly with the Gutenberg-Richter frequency-magnitude statistics. We considered a synthetic catalog of 1.97 × 10^5 M_{λ } ≥ 7.0 earthquakes and found β = 0.99 ± 0.01. The random catalog converted to natural time was also random. We then generated 1.5 × 10^4 synthetic catalogs with 197 M_{λ } ≥ 7.0 in each catalog and

Earthquake hazard assessment and small earthquakes

International Nuclear Information System (INIS)

Reiter, L.

1987-01-01

The significance of small earthquakes and their treatment in nuclear power plant seismic hazard assessment is an issue which has received increased attention over the past few years. In probabilistic studies, sensitivity studies showed that the choice of the lower bound magnitude used in hazard calculations can have a larger than expected effect on the calculated hazard. Of particular interest is the fact that some of the difference in seismic hazard calculations between the Lawrence Livermore National Laboratory (LLNL) and Electric Power Research Institute (EPRI) studies can be attributed to this choice. The LLNL study assumed a lower bound magnitude of 3.75 while the EPRI study assumed a lower bound magnitude of 5.0. The magnitudes used were assumed to be body wave magnitudes or their equivalents. In deterministic studies recent ground motion recordings of small to moderate earthquakes at or near nuclear power plants have shown that the high frequencies of design response spectra may be exceeded. These exceedances became important issues in the licensing of the Summer and Perry nuclear power plants. At various times in the past particular concerns have been raised with respect to the hazard and damage potential of small to moderate earthquakes occurring at very shallow depths. In this paper a closer look is taken at these issues. Emphasis is given to the impact of lower bound magnitude on probabilistic hazard calculations and the historical record of damage from small to moderate earthquakes. Limited recommendations are made as to how these issues should be viewed

Extreme value distribution of earthquake magnitude

Science.gov (United States)

Zi, Jun Gan; Tung, C. C.

1983-07-01

Probability distribution of maximum earthquake magnitude is first derived for an unspecified probability distribution of earthquake magnitude. A model for energy release of large earthquakes, similar to that of Adler-Lomnitz and Lomnitz, is introduced from which the probability distribution of earthquake magnitude is obtained. An extensive set of world data for shallow earthquakes, covering the period from 1904 to 1980, is used to determine the parameters of the probability distribution of maximum earthquake magnitude. Because of the special form of probability distribution of earthquake magnitude, a simple iterative scheme is devised to facilitate the estimation of these parameters by the method of least-squares. The agreement between the empirical and derived probability distributions of maximum earthquake magnitude is excellent.

Historic Eastern Canadian earthquakes

International Nuclear Information System (INIS)

Asmis, G.J.K.; Atchinson, R.J.

1981-01-01

Nuclear power plants licensed in Canada have been designed to resist earthquakes: not all plants, however, have been explicitly designed to the same level of earthquake induced forces. Understanding the nature of strong ground motion near the source of the earthquake is still very tentative. This paper reviews historical and scientific accounts of the three strongest earthquakes - St. Lawrence (1925), Temiskaming (1935), Cornwall (1944) - that have occurred in Canada in 'modern' times, field studies of near-field strong ground motion records and their resultant damage or non-damage to industrial facilities, and numerical modelling of earthquake sources and resultant wave propagation to produce accelerograms consistent with the above historical record and field studies. It is concluded that for future construction of NPP's near-field strong motion must be explicitly considered in design

Earthquakes: hydrogeochemical precursors

Science.gov (United States)

Ingebritsen, Steven E.; Manga, Michael

2014-01-01

Earthquake prediction is a long-sought goal. Changes in groundwater chemistry before earthquakes in Iceland highlight a potential hydrogeochemical precursor, but such signals must be evaluated in the context of long-term, multiparametric data sets.

Children's Ideas about Earthquakes

Science.gov (United States)

Simsek, Canan Lacin

2007-01-01

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…

Excel, Earthquakes, and Moneyball: exploring Cascadia earthquake probabilities using spreadsheets and baseball analogies

Science.gov (United States)

Campbell, M. R.; Salditch, L.; Brooks, E. M.; Stein, S.; Spencer, B. D.

2017-12-01

Much recent media attention focuses on Cascadia's earthquake hazard. A widely cited magazine article starts "An earthquake will destroy a sizable portion of the coastal Northwest. The question is when." Stories include statements like "a massive earthquake is overdue", "in the next 50 years, there is a 1-in-10 chance a "really big one" will erupt," or "the odds of the big Cascadia earthquake happening in the next fifty years are roughly one in three." These lead students to ask where the quoted probabilities come from and what they mean. These probability estimates involve two primary choices: what data are used to describe when past earthquakes happened and what models are used to forecast when future earthquakes will happen. The data come from a 10,000-year record of large paleoearthquakes compiled from subsidence data on land and turbidites, offshore deposits recording submarine slope failure. Earthquakes seem to have happened in clusters of four or five events, separated by gaps. Earthquakes within a cluster occur more frequently and regularly than in the full record. Hence the next earthquake is more likely if we assume that we are in the recent cluster that started about 1700 years ago, than if we assume the cluster is over. Students can explore how changing assumptions drastically changes probability estimates using easy-to-write and display spreadsheets, like those shown below. Insight can also come from baseball analogies. The cluster issue is like deciding whether to assume that a hitter's performance in the next game is better described by his lifetime record, or by the past few games, since he may be hitting unusually well or in a slump. The other big choice is whether to assume that the probability of an earthquake is constant with time, or is small immediately after one occurs and then grows with time. This is like whether to assume that a player's performance is the same from year to year, or changes over their career. Thus saying "the chance of

Do Earthquakes Shake Stock Markets?

Science.gov (United States)

Ferreira, Susana; Karali, Berna

2015-01-01

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.

Report `A field test project for the disaster prevention type photovoltaic power generation (Kobe city, Hyogo prefecture)`; `Bosaigata taiyoko hatsuden field test jigyo (Hyogoken Kobeshi)` hokokusho

Energy Technology Data Exchange (ETDEWEB)

NONE

1996-09-12

An experiment was conducted on the introduction of the disaster prevention type photovoltaic power system provided with storage batteries to public facilities, etc., considering not only the use of new energy from the environmental aspect, but the emergency use. In fiscal 1995, 5kW-output photovoltaic power systems were installed on the rooftop of Hiyodori and Takamaru regional welfare centers and a 30kW photovoltaic power system on the rooftop of the Hyogo Ward Office. Demonstrative tests of these systems started for collection of various data. Now that the systems were installed at the regional welfare center managed mostly by regional citizens and the ward office which is an administrative office familiar with regional residents, the understanding of and familiarity with the photovoltaic power system were obtained from regional residents, and also people were enlightened on the use of solar energy in such a point as economization of power rates using the interconnected power system. Further, for life supports, it was made possible to secure minimum electric power in emergency and to secure functions of disaster prevention spots. 3 figs.

Toward real-time regional earthquake simulation II: Real-time Online earthquake Simulation (ROS) of Taiwan earthquakes

Science.gov (United States)

Lee, Shiann-Jong; Liu, Qinya; Tromp, Jeroen; Komatitsch, Dimitri; Liang, Wen-Tzong; Huang, Bor-Shouh

2014-06-01

We developed a Real-time Online earthquake Simulation system (ROS) to simulate regional earthquakes in Taiwan. The ROS uses a centroid moment tensor solution of seismic events from a Real-time Moment Tensor monitoring system (RMT), which provides all the point source parameters including the event origin time, hypocentral location, moment magnitude and focal mechanism within 2 min after the occurrence of an earthquake. Then, all of the source parameters are automatically forwarded to the ROS to perform an earthquake simulation, which is based on a spectral-element method (SEM). A new island-wide, high resolution SEM mesh model is developed for the whole Taiwan in this study. We have improved SEM mesh quality by introducing a thin high-resolution mesh layer near the surface to accommodate steep and rapidly varying topography. The mesh for the shallow sedimentary basin is adjusted to reflect its complex geometry and sharp lateral velocity contrasts. The grid resolution at the surface is about 545 m, which is sufficient to resolve topography and tomography data for simulations accurate up to 1.0 Hz. The ROS is also an infrastructural service, making online earthquake simulation feasible. Users can conduct their own earthquake simulation by providing a set of source parameters through the ROS webpage. For visualization, a ShakeMovie and ShakeMap are produced during the simulation. The time needed for one event is roughly 3 min for a 70 s ground motion simulation. The ROS is operated online at the Institute of Earth Sciences, Academia Sinica (http://ros.earth.sinica.edu.tw/). Our long-term goal for the ROS system is to contribute to public earth science outreach and to realize seismic ground motion prediction in real-time.

Sedimentary Signatures of Submarine Earthquakes: Deciphering the Extent of Sediment Remobilization from the 2011 Tohoku Earthquake and Tsunami and 2010 Haiti Earthquake

Science.gov (United States)

McHugh, C. M.; Seeber, L.; Moernaut, J.; Strasser, M.; Kanamatsu, T.; Ikehara, K.; Bopp, R.; Mustaque, S.; Usami, K.; Schwestermann, T.; Kioka, A.; Moore, L. M.

2017-12-01

The 2004 Sumatra-Andaman Mw9.3 and the 2011 Tohoku (Japan) Mw9.0 earthquakes and tsunamis were huge geological events with major societal consequences. Both were along subduction boundaries and ruptured portions of these boundaries that had been deemed incapable of such events. Submarine strike-slip earthquakes, such as the 2010 Mw7.0 in Haiti, are smaller but may be closer to population centers and can be similarly catastrophic. Both classes of earthquakes remobilize sediment and leave distinct signatures in the geologic record by a wide range of processes that depends on both environment and earthquake characteristics. Understanding them has the potential of greatly expanding the record of past earthquakes, which is critical for geohazard analysis. Recent events offer precious ground truth about the earthquakes and short-lived radioisotopes offer invaluable tools to identify sediments they remobilized. In the 2011 Mw9 Japan earthquake they document the spatial extent of remobilized sediment from water depths of 626m in the forearc slope to trench depths of 8000m. Subbottom profiles, multibeam bathymetry and 40 piston cores collected by the R/V Natsushima and R/V Sonne expeditions to the Japan Trench document multiple turbidites and high-density flows. Core tops enriched in xs210Pb,137Cs and 134Cs reveal sediment deposited by the 2011 Tohoku earthquake and tsunami. The thickest deposits (2m) were documented on a mid-slope terrace and trench (4000-8000m). Sediment was deposited on some terraces (600-3000m), but shed from the steep forearc slope (3000-4000m). The 2010 Haiti mainshock ruptured along the southern flank of Canal du Sud and triggered multiple nearshore sediment failures, generated turbidity currents and stirred fine sediment into suspension throughout this basin. A tsunami was modeled to stem from both sediment failures and tectonics. Remobilized sediment was tracked with short-lived radioisotopes from the nearshore, slope, in fault basins including the

Analysis of pre-earthquake ionospheric anomalies before the global M = 7.0+ earthquakes in 2010

Directory of Open Access Journals (Sweden)

W. F. Peng

2012-03-01

Full Text Available The pre-earthquake ionospheric anomalies that occurred before the global M = 7.0+ earthquakes in 2010 are investigated using the total electron content (TEC from the global ionosphere map (GIM. We analyze the possible causes of the ionospheric anomalies based on the space environment and magnetic field status. Results show that some anomalies are related to the earthquakes. By analyzing the time of occurrence, duration, and spatial distribution of these ionospheric anomalies, a number of new conclusions are drawn, as follows: earthquake-related ionospheric anomalies are not bound to appear; both positive and negative anomalies are likely to occur; and the earthquake-related ionospheric anomalies discussed in the current study occurred 0–2 days before the associated earthquakes and in the afternoon to sunset (i.e. between 12:00 and 20:00 local time. Pre-earthquake ionospheric anomalies occur mainly in areas near the epicenter. However, the maximum affected area in the ionosphere does not coincide with the vertical projection of the epicenter of the subsequent earthquake. The directions deviating from the epicenters do not follow a fixed rule. The corresponding ionospheric effects can also be observed in the magnetically conjugated region. However, the probability of the anomalies appearance and extent of the anomalies in the magnetically conjugated region are smaller than the anomalies near the epicenter. Deep-focus earthquakes may also exhibit very significant pre-earthquake ionospheric anomalies.

The 2008 Wenchuan Earthquake and the Rise and Fall of Earthquake Prediction in China

Science.gov (United States)

Chen, Q.; Wang, K.

2009-12-01

Regardless of the future potential of earthquake prediction, it is presently impractical to rely on it to mitigate earthquake disasters. The practical approach is to strengthen the resilience of our built environment to earthquakes based on hazard assessment. But this was not common understanding in China when the M 7.9 Wenchuan earthquake struck the Sichuan Province on 12 May 2008, claiming over 80,000 lives. In China, earthquake prediction is a government-sanctioned and law-regulated measure of disaster prevention. A sudden boom of the earthquake prediction program in 1966-1976 coincided with a succession of nine M > 7 damaging earthquakes in the densely populated region of the country and the political chaos of the Cultural Revolution. It climaxed with the prediction of the 1975 Haicheng earthquake, which was due mainly to an unusually pronounced foreshock sequence and the extraordinary readiness of some local officials to issue imminent warning and evacuation order. The Haicheng prediction was a success in practice and yielded useful lessons, but the experience cannot be applied to most other earthquakes and cultural environments. Since the disastrous Tangshan earthquake in 1976 that killed over 240,000 people, there have been two opposite trends in China: decreasing confidence in prediction and increasing emphasis on regulating construction design for earthquake resilience. In 1976, most of the seismic intensity XI areas of Tangshan were literally razed to the ground, but in 2008, many buildings in the intensity XI areas of Wenchuan did not collapse. Prediction did not save life in either of these events; the difference was made by construction standards. For regular buildings, there was no seismic design in Tangshan to resist any earthquake shaking in 1976, but limited seismic design was required for the Wenchuan area in 2008. Although the construction standards were later recognized to be too low, those buildings that met the standards suffered much less

1/f and the Earthquake Problem: Scaling constraints that facilitate operational earthquake forecasting

Science.gov (United States)

yoder, M. R.; Rundle, J. B.; Turcotte, D. L.

2012-12-01

The difficulty of forecasting earthquakes can fundamentally be attributed to the self-similar, or "1/f", nature of seismic sequences. Specifically, the rate of occurrence of earthquakes is inversely proportional to their magnitude m, or more accurately to their scalar moment M. With respect to this "1/f problem," it can be argued that catalog selection (or equivalently, determining catalog constraints) constitutes the most significant challenge to seismicity based earthquake forecasting. Here, we address and introduce a potential solution to this most daunting problem. Specifically, we introduce a framework to constrain, or partition, an earthquake catalog (a study region) in order to resolve local seismicity. In particular, we combine Gutenberg-Richter (GR), rupture length, and Omori scaling with various empirical measurements to relate the size (spatial and temporal extents) of a study area (or bins within a study area) to the local earthquake magnitude potential - the magnitude of earthquake the region is expected to experience. From this, we introduce a new type of time dependent hazard map for which the tuning parameter space is nearly fully constrained. In a similar fashion, by combining various scaling relations and also by incorporating finite extents (rupture length, area, and duration) as constraints, we develop a method to estimate the Omori (temporal) and spatial aftershock decay parameters as a function of the parent earthquake's magnitude m. From this formulation, we develop an ETAS type model that overcomes many point-source limitations of contemporary ETAS. These models demonstrate promise with respect to earthquake forecasting applications. Moreover, the methods employed suggest a general framework whereby earthquake and other complex-system, 1/f type, problems can be constrained from scaling relations and finite extents.; Record-breaking hazard map of southern California, 2012-08-06. "Warm" colors indicate local acceleration (elevated hazard

Post-earthquake building safety inspection: Lessons from the Canterbury, New Zealand, earthquakes

Science.gov (United States)

Marshall, J.; Jaiswal, Kishor; Gould, N.; Turner, F.; Lizundia, B.; Barnes, J.

2013-01-01

The authors discuss some of the unique aspects and lessons of the New Zealand post-earthquake building safety inspection program that was implemented following the Canterbury earthquake sequence of 2010–2011. The post-event safety assessment program was one of the largest and longest programs undertaken in recent times anywhere in the world. The effort engaged hundreds of engineering professionals throughout the country, and also sought expertise from outside, to perform post-earthquake structural safety inspections of more than 100,000 buildings in the city of Christchurch and the surrounding suburbs. While the building safety inspection procedure implemented was analogous to the ATC 20 program in the United States, many modifications were proposed and implemented in order to assess the large number of buildings that were subjected to strong and variable shaking during a period of two years. This note discusses some of the key aspects of the post-earthquake building safety inspection program and summarizes important lessons that can improve future earthquake response.

Extreme value statistics and thermodynamics of earthquakes: large earthquakes

Directory of Open Access Journals (Sweden)

B. H. Lavenda

2000-06-01

Full Text Available A compound Poisson process is used to derive a new shape parameter which can be used to discriminate between large earthquakes and aftershock sequences. Sample exceedance distributions of large earthquakes are fitted to the Pareto tail and the actual distribution of the maximum to the Fréchet distribution, while the sample distribution of aftershocks are fitted to a Beta distribution and the distribution of the minimum to the Weibull distribution for the smallest value. The transition between initial sample distributions and asymptotic extreme value distributions shows that self-similar power laws are transformed into nonscaling exponential distributions so that neither self-similarity nor the Gutenberg-Richter law can be considered universal. The energy-magnitude transformation converts the Fréchet distribution into the Gumbel distribution, originally proposed by Epstein and Lomnitz, and not the Gompertz distribution as in the Lomnitz-Adler and Lomnitz generalization of the Gutenberg-Richter law. Numerical comparison is made with the Lomnitz-Adler and Lomnitz analysis using the same Catalogue of Chinese Earthquakes. An analogy is drawn between large earthquakes and high energy particle physics. A generalized equation of state is used to transform the Gamma density into the order-statistic Fréchet distribution. Earthquaketemperature and volume are determined as functions of the energy. Large insurance claims based on the Pareto distribution, which does not have a right endpoint, show why there cannot be a maximum earthquake energy.

Countermeasures to earthquakes in nuclear plants

International Nuclear Information System (INIS)

Sato, Kazuhide

1979-01-01

The contribution of atomic energy to mankind is unmeasured, but the danger of radioactivity is a special thing. Therefore in the design of nuclear power plants, the safety has been regarded as important, and in Japan where earthquakes occur frequently, the countermeasures to earthquakes have been incorporated in the examination of safety naturally. The radioactive substances handled in nuclear power stations and spent fuel reprocessing plants are briefly explained. The occurrence of earthquakes cannot be predicted effectively, and the disaster due to earthquakes is apt to be remarkably large. In nuclear plants, the prevention of damage in the facilities and the maintenance of the functions are required at the time of earthquakes. Regarding the location of nuclear plants, the history of earthquakes, the possible magnitude of earthquakes, the properties of ground and the position of nuclear plants should be examined. After the place of installation has been decided, the earthquake used for design is selected, evaluating live faults and determining the standard earthquakes. As the fundamentals of aseismatic design, the classification according to importance, the earthquakes for design corresponding to the classes of importance, the combination of loads and allowable stress are explained. (Kako, I.)

Do earthquakes exhibit self-organized criticality?

International Nuclear Information System (INIS)

Yang Xiaosong; Ma Jin; Du Shuming

2004-01-01

If earthquakes are phenomena of self-organized criticality (SOC), statistical characteristics of the earthquake time series should be invariant after the sequence of events in an earthquake catalog are randomly rearranged. In this Letter we argue that earthquakes are unlikely phenomena of SOC because our analysis of the Southern California Earthquake Catalog shows that the first-return-time probability P M (T) is apparently changed after the time series is rearranged. This suggests that the SOC theory should not be used to oppose the efforts of earthquake prediction

Earthquake precursors: spatial-temporal gravity changes before the great earthquakes in the Sichuan-Yunnan area

Science.gov (United States)

Zhu, Yi-Qing; Liang, Wei-Feng; Zhang, Song

2018-01-01

Using multiple-scale mobile gravity data in the Sichuan-Yunnan area, we systematically analyzed the relationships between spatial-temporal gravity changes and the 2014 Ludian, Yunnan Province Ms6.5 earthquake and the 2014 Kangding Ms6.3, 2013 Lushan Ms7.0, and 2008 Wenchuan Ms8.0 earthquakes in Sichuan Province. Our main results are as follows. (1) Before the occurrence of large earthquakes, gravity anomalies occur in a large area around the epicenters. The directions of gravity change gradient belts usually agree roughly with the directions of the main fault zones of the study area. Such gravity changes might reflect the increase of crustal stress, as well as the significant active tectonic movements and surface deformations along fault zones, during the period of gestation of great earthquakes. (2) Continuous significant changes of the multiple-scale gravity fields, as well as greater gravity changes with larger time scales, can be regarded as medium-range precursors of large earthquakes. The subsequent large earthquakes always occur in the area where the gravity changes greatly. (3) The spatial-temporal gravity changes are very useful in determining the epicenter of coming large earthquakes. The large gravity networks are useful to determine the general areas of coming large earthquakes. However, the local gravity networks with high spatial-temporal resolution are suitable for determining the location of epicenters. Therefore, denser gravity observation networks are necessary for better forecasts of the epicenters of large earthquakes. (4) Using gravity changes from mobile observation data, we made medium-range forecasts of the Kangding, Ludian, Lushan, and Wenchuan earthquakes, with especially successful forecasts of the location of their epicenters. Based on the above discussions, we emphasize that medium-/long-term potential for large earthquakes might exist nowadays in some areas with significant gravity anomalies in the study region. Thus, the monitoring

Overestimation of the earthquake hazard along the Himalaya: constraints in bracketing of medieval earthquakes from paleoseismic studies

Science.gov (United States)

Arora, Shreya; Malik, Javed N.

2017-12-01

The Himalaya is one of the most seismically active regions of the world. The occurrence of several large magnitude earthquakes viz. 1905 Kangra earthquake (Mw 7.8), 1934 Bihar-Nepal earthquake (Mw 8.2), 1950 Assam earthquake (Mw 8.4), 2005 Kashmir (Mw 7.6), and 2015 Gorkha (Mw 7.8) are the testimony to ongoing tectonic activity. In the last few decades, tremendous efforts have been made along the Himalayan arc to understand the patterns of earthquake occurrences, size, extent, and return periods. Some of the large magnitude earthquakes produced surface rupture, while some remained blind. Furthermore, due to the incompleteness of the earthquake catalogue, a very few events can be correlated with medieval earthquakes. Based on the existing paleoseismic data certainly, there exists a complexity to precisely determine the extent of surface rupture of these earthquakes and also for those events, which occurred during historic times. In this paper, we have compiled the paleo-seismological data and recalibrated the radiocarbon ages from the trenches excavated by previous workers along the entire Himalaya and compared earthquake scenario with the past. Our studies suggest that there were multiple earthquake events with overlapping surface ruptures in small patches with an average rupture length of 300 km limiting Mw 7.8-8.0 for the Himalayan arc, rather than two or three giant earthquakes rupturing the whole front. It has been identified that the large magnitude Himalayan earthquakes, such as 1905 Kangra, 1934 Bihar-Nepal, and 1950 Assam, that have occurred within a time frame of 45 years. Now, if these events are dated, there is a high possibility that within the range of ±50 years, they may be considered as the remnant of one giant earthquake rupturing the entire Himalayan arc. Therefore, leading to an overestimation of seismic hazard scenario in Himalaya.

Stress triggering of the Lushan M7. 0 earthquake by the Wenchuan Ms8. 0 earthquake

Directory of Open Access Journals (Sweden)

Wu Jianchao

2013-08-01

Full Text Available The Wenchuan Ms8. 0 earthquake and the Lushan M7. 0 earthquake occurred in the north and south segments of the Longmenshan nappe tectonic belt, respectively. Based on the focal mechanism and finite fault model of the Wenchuan Ms8. 0 earthquake, we calculated the coulomb failure stress change. The inverted coulomb stress changes based on the Nishimura and Chenji models both show that the Lushan M7. 0 earthquake occurred in the increased area of coulomb failure stress induced by the Wenchuan Ms8. 0 earthquake. The coulomb failure stress increased by approximately 0. 135 – 0. 152 bar in the source of the Lushan M7. 0 earthquake, which is far more than the stress triggering threshold. Therefore, the Lushan M7. 0 earthquake was most likely triggered by the coulomb failure stress change.

Earthquake engineering for nuclear facilities

CERN Document Server

Kuno, Michiya

2017-01-01

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...

Sensing the earthquake

Science.gov (United States)

Bichisao, Marta; Stallone, Angela

2017-04-01

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.

Thoracic Injuries in earthquake-related versus non-earthquake-related trauma patients: differentiation via Multi-detector Computed Tomography

Science.gov (United States)

Dong, Zhi-hui; Yang, Zhi-gang; Chen, Tian-wu; Chu, Zhi-gang; Deng, Wen; Shao, Heng

2011-01-01

PURPOSE: Massive earthquakes are harmful to humankind. This study of a historical cohort aimed to investigate the difference between earthquake-related crush thoracic traumas and thoracic traumas unrelated to earthquakes using a multi-detector Computed Tomography (CT). METHODS: We retrospectively compared an earthquake-exposed cohort of 215 thoracic trauma crush victims of the Sichuan earthquake to a cohort of 215 non-earthquake-related thoracic trauma patients, focusing on the lesions and coexisting injuries to the thoracic cage and the pulmonary parenchyma and pleura using a multi-detector CT. RESULTS: The incidence of rib fracture was elevated in the earthquake-exposed cohort (143 vs. 66 patients in the non-earthquake-exposed cohort, Risk Ratio (RR) = 2.2; pchest (45/143 vs. 11/66 patients, RR = 1.9; ptraumas resulting from the earthquake were life threatening with a high incidence of bony thoracic fractures. The ribs were frequently involved in bilateral and severe types of fractures, which were accompanied by non-rib fractures, pulmonary parenchymal and pleural injuries. PMID:21789386

Consideration for standard earthquake vibration (1). The Niigataken Chuetsu-oki Earthquake in 2007

International Nuclear Information System (INIS)

Ishibashi, Katsuhiko

2007-01-01

Outline of new guideline of quakeproof design standard of nuclear power plant and the standard earthquake vibration are explained. The improvement points of new guideline are discussed on the basis of Kashiwazaki-Kariwa Nuclear Power Plant incidents. The fundamental limits of new guideline are pointed. Placement of the quakeproof design standard of nuclear power plant, JEAG4601 of Japan Electric Association, new guideline, standard earthquake vibration of new guideline, the Niigataken Chuetsu-oki Earthquake in 2007 and damage of Kashiwazaki-Kariwa Nuclear Power Plant are discussed. The safety criteria of safety review system, organization, standard and guideline should be improved on the basis of this earthquake and nuclear plant accident. The general knowledge, 'a nuclear power plant is not constructed in the area expected large earthquake', has to be realized. Preconditions of all nuclear power plants should not cause damage to anything. (S.Y.)

Earthquake Emergency Education in Dushanbe, Tajikistan

Science.gov (United States)

Mohadjer, Solmaz; Bendick, Rebecca; Halvorson, Sarah J.; Saydullaev, Umed; Hojiboev, Orifjon; Stickler, Christine; Adam, Zachary R.

2010-01-01

We developed a middle school earthquake science and hazards curriculum to promote earthquake awareness to students in the Central Asian country of Tajikistan. These materials include pre- and post-assessment activities, six science activities describing physical processes related to earthquakes, five activities on earthquake hazards and mitigation…

Intensity earthquake scenario (scenario event - a damaging earthquake with higher probability of occurrence) for the city of Sofia

Science.gov (United States)

Aleksandrova, Irena; Simeonova, Stela; Solakov, Dimcho; Popova, Maria

2014-05-01

Among the many kinds of natural and man-made disasters, earthquakes dominate with regard to their social and economical impact on the urban environment. Global seismic risk to earthquakes are increasing steadily as urbanization and development occupy more areas that a prone to effects of strong earthquakes. Additionally, the uncontrolled growth of mega cities in highly seismic areas around the world is often associated with the construction of seismically unsafe buildings and infrastructures, and undertaken with an insufficient knowledge of the regional seismicity peculiarities and seismic hazard. The assessment of seismic hazard and generation of earthquake scenarios is the first link in the prevention chain and the first step in the evaluation of the seismic risk. The earthquake scenarios are intended as a basic input for developing detailed earthquake damage scenarios for the cities and can be used in earthquake-safe town and infrastructure planning. The city of Sofia is the capital of Bulgaria. It is situated in the centre of the Sofia area that is the most populated (the population is of more than 1.2 mil. inhabitants), industrial and cultural region of Bulgaria that faces considerable earthquake risk. 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=9-10 MSK. During the 20th century the strongest event occurred in the vicinity of the city of Sofia is the 1917 earthquake with MS=5.3 (I0=7-8 MSK). Almost a century later (95 years) an earthquake of moment magnitude 5.6 (I0=7-8 MSK) hit the city of Sofia, on May 22nd, 2012. In the present study as a deterministic scenario event is considered a damaging earthquake with higher probability of occurrence that could affect the city with intensity less than or equal to VIII

Earthquake recurrence models fail when earthquakes fail to reset the stress field

Science.gov (United States)

Tormann, Thessa; Wiemer, Stefan; Hardebeck, Jeanne L.

2012-01-01

Parkfield's regularly occurring M6 mainshocks, about every 25 years, have over two decades stoked seismologists' hopes to successfully predict an earthquake of significant size. However, with the longest known inter-event time of 38 years, the latest M6 in the series (28 Sep 2004) did not conform to any of the applied forecast models, questioning once more the predictability of earthquakes in general. Our study investigates the spatial pattern of b-values along the Parkfield segment through the seismic cycle and documents a stably stressed structure. The forecasted rate of M6 earthquakes based on Parkfield's microseismicity b-values corresponds well to observed rates. We interpret the observed b-value stability in terms of the evolution of the stress field in that area: the M6 Parkfield earthquakes do not fully unload the stress on the fault, explaining why time recurrent models fail. We present the 1989 M6.9 Loma Prieta earthquake as counter example, which did release a significant portion of the stress along its fault segment and yields a substantial change in b-values.

Earthquake Damage Assessment Using Objective Image Segmentation: A Case Study of 2010 Haiti Earthquake

Science.gov (United States)

Oommen, Thomas; Rebbapragada, Umaa; Cerminaro, Daniel

2012-01-01

In this study, we perform a case study on imagery from the Haiti earthquake that evaluates a novel object-based approach for characterizing earthquake induced surface effects of liquefaction against a traditional pixel based change technique. Our technique, which combines object-oriented change detection with discriminant/categorical functions, shows the power of distinguishing earthquake-induced surface effects from changes in buildings using the object properties concavity, convexity, orthogonality and rectangularity. Our results suggest that object-based analysis holds promise in automatically extracting earthquake-induced damages from high-resolution aerial/satellite imagery.

The CATDAT damaging earthquakes database

Science.gov (United States)

Daniell, J. E.; Khazai, B.; Wenzel, F.; Vervaeck, A.

2011-08-01

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 reinsurance field.

The CATDAT damaging earthquakes database

Directory of Open Access Journals (Sweden)

J. E. Daniell

2011-08-01

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

Comparison of aftershock sequences between 1975 Haicheng earthquake and 1976 Tangshan earthquake

Science.gov (United States)

Liu, B.

2017-12-01

The 1975 ML 7.3 Haicheng earthquake and the 1976 ML 7.8 Tangshan earthquake occurred in the same tectonic unit. There are significant differences in spatial-temporal distribution, number of aftershocks and time duration for the aftershock sequence followed by these two main shocks. As we all know, aftershocks could be triggered by the regional seismicity change derived from the main shock, which was caused by the Coulomb stress perturbation. Based on the rate- and state- dependent friction law, we quantitative estimated the possible aftershock time duration with a combination of seismicity data, and compared the results from different approaches. The results indicate that, aftershock time durations from the Tangshan main shock is several times of that form the Haicheng main shock. This can be explained by the significant relationship between aftershock time duration and earthquake nucleation history, normal stressand shear stress loading rateon the fault. In fact the obvious difference of earthquake nucleation history from these two main shocks is the foreshocks. 1975 Haicheng earthquake has clear and long foreshocks, while 1976 Tangshan earthquake did not have clear foreshocks. In that case, abundant foreshocks may mean a long and active nucleation process that may have changed (weakened) the rocks in the source regions, so they should have a shorter aftershock sequences for the reason that stress in weak rocks decay faster.

Ionospheric phenomena before strong earthquakes

Directory of Open Access Journals (Sweden)

A. S. Silina

2001-01-01

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.

Tradable Earthquake Certificates

NARCIS (Netherlands)

Woerdman, Edwin; Dulleman, Minne

2018-01-01

This article presents a market-based idea to compensate for earthquake damage caused by the extraction of natural gas and applies it to the case of Groningen in the Netherlands. Earthquake certificates give homeowners a right to yearly compensation for both property damage and degradation of living

What Can Sounds Tell Us About Earthquake Interactions?

Science.gov (United States)

Aiken, C.; Peng, Z.

2012-12-01

It is important not only for seismologists but also for educators to effectively convey information about earthquakes and the influences earthquakes can have on each other. Recent studies using auditory display [e.g. Kilb et al., 2012; Peng et al. 2012] have depicted catastrophic earthquakes and the effects large earthquakes can have on other parts of the world. Auditory display of earthquakes, which combines static images with time-compressed sound of recorded seismic data, is a new approach to disseminating information to a general audience about earthquakes and earthquake interactions. Earthquake interactions are influential to understanding the underlying physics of earthquakes and other seismic phenomena such as tremors in addition to their source characteristics (e.g. frequency contents, amplitudes). Earthquake interactions can include, for example, a large, shallow earthquake followed by increased seismicity around the mainshock rupture (i.e. aftershocks) or even a large earthquake triggering earthquakes or tremors several hundreds to thousands of kilometers away [Hill and Prejean, 2007; Peng and Gomberg, 2010]. We use standard tools like MATLAB, QuickTime Pro, and Python to produce animations that illustrate earthquake interactions. Our efforts are focused on producing animations that depict cross-section (side) views of tremors triggered along the San Andreas Fault by distant earthquakes, as well as map (bird's eye) views of mainshock-aftershock sequences such as the 2011/08/23 Mw5.8 Virginia earthquake sequence. These examples of earthquake interactions include sonifying earthquake and tremor catalogs as musical notes (e.g. piano keys) as well as audifying seismic data using time-compression. Our overall goal is to use auditory display to invigorate a general interest in earthquake seismology that leads to the understanding of how earthquakes occur, how earthquakes influence one another as well as tremors, and what the musical properties of these

A smartphone application for earthquakes that matter!

Science.gov (United States)

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

2014-05-01

Smartphone applications have swiftly become one of the most popular tools for rapid reception of earthquake information for the public, some of them having been downloaded more than 1 million times! The advantages are obvious: wherever someone's own location is, they can be automatically informed when an earthquake has struck. Just by setting a magnitude threshold and an area of interest, there is no longer the need to browse the internet as the information reaches you automatically and instantaneously! One question remains: are the provided earthquake notifications always relevant for the public? What are the earthquakes that really matters to laypeople? One clue may be derived from some newspaper reports that show that a while after damaging earthquakes many eyewitnesses scrap the application they installed just after the mainshock. Why? Because either the magnitude threshold is set too high and many felt earthquakes are missed, or it is set too low and the majority of the notifications are related to unfelt earthquakes thereby only increasing anxiety among the population at each new update. Felt and damaging earthquakes are the ones that matter the most for the public (and authorities). They are the ones of societal importance even when of small magnitude. A smartphone application developed by EMSC (Euro-Med Seismological Centre) with the financial support of the Fondation MAIF aims at providing suitable notifications for earthquakes by collating different information threads covering tsunamigenic, potentially damaging and felt earthquakes. Tsunamigenic earthquakes are considered here to be those ones that are the subject of alert or information messages from the PTWC (Pacific Tsunami Warning Centre). While potentially damaging earthquakes are identified through an automated system called EQIA (Earthquake Qualitative Impact Assessment) developed and operated at EMSC. This rapidly assesses earthquake impact by comparing the population exposed to each expected

Nowcasting Earthquakes and Tsunamis

Science.gov (United States)

Rundle, J. B.; Turcotte, D. L.

2017-12-01

The term "nowcasting" refers to the estimation of the current uncertain state of a dynamical system, whereas "forecasting" is a calculation of probabilities of future state(s). Nowcasting is a term that originated in economics and finance, referring to the process of determining the uncertain state of the economy or market indicators such as GDP at the current time by indirect means. We have applied this idea to seismically active regions, where the goal is to determine the current state of a system of faults, and its current level of progress through the earthquake cycle (http://onlinelibrary.wiley.com/doi/10.1002/2016EA000185/full). Advantages of our nowcasting method over forecasting models include: 1) Nowcasting is simply data analysis and does not involve a model having parameters that must be fit to data; 2) We use only earthquake catalog data which generally has known errors and characteristics; and 3) We use area-based analysis rather than fault-based analysis, meaning that the methods work equally well on land and in subduction zones. To use the nowcast method to estimate how far the fault system has progressed through the "cycle" of large recurring earthquakes, we use the global catalog of earthquakes, using "small" earthquakes to determine the level of hazard from "large" earthquakes in the region. We select a "small" region in which the nowcast is to be made, and compute the statistics of a much larger region around the small region. The statistics of the large region are then applied to the small region. For an application, we can define a small region around major global cities, for example a "small" circle of radius 150 km and a depth of 100 km, as well as a "large" earthquake magnitude, for example M6.0. The region of influence of such earthquakes is roughly 150 km radius x 100 km depth, which is the reason these values were selected. We can then compute and rank the seismic risk of the world's major cities in terms of their relative seismic risk

Seismicity map tools for earthquake studies

Science.gov (United States)

Boucouvalas, Anthony; Kaskebes, Athanasios; Tselikas, Nikos

2014-05-01

We report on the development of new and online set of tools for use within Google Maps, for earthquake research. We demonstrate this server based and online platform (developped with PHP, Javascript, MySQL) with the new tools using a database system with earthquake data. The platform allows us to carry out statistical and deterministic analysis on earthquake data use of Google Maps and plot various seismicity graphs. The tool box has been extended to draw on the map line segments, multiple straight lines horizontally and vertically as well as multiple circles, including geodesic lines. The application is demonstrated using localized seismic data from the geographic region of Greece as well as other global earthquake data. The application also offers regional segmentation (NxN) which allows the studying earthquake clustering, and earthquake cluster shift within the segments in space. The platform offers many filters such for plotting selected magnitude ranges or time periods. The plotting facility allows statistically based plots such as cumulative earthquake magnitude plots and earthquake magnitude histograms, calculation of 'b' etc. What is novel for the platform is the additional deterministic tools. Using the newly developed horizontal and vertical line and circle tools we have studied the spatial distribution trends of many earthquakes and we here show for the first time the link between Fibonacci Numbers and spatiotemporal location of some earthquakes. The new tools are valuable for examining visualizing trends in earthquake research as it allows calculation of statistics as well as deterministic precursors. We plan to show many new results based on our newly developed platform.

Earthquake at 40 feet

Science.gov (United States)

Miller, G. J.

1976-01-01

The earthquake that struck the island of Guam on November 1, 1975, at 11:17 a.m had many unique aspects-not the least of which was the experience of an earthquake of 6.25 Richter magnitude while at 40 feet. My wife Bonnie, a fellow diver, Greg Guzman, and I were diving at Gabgab Beach in teh outer harbor of Apra Harbor, engaged in underwater phoyography when the earthquake struck. 

Earthquakes and economic growth

OpenAIRE

Fisker, Peter Simonsen

2012-01-01

This study explores the economic consequences of earthquakes. In particular, it is investigated how exposure to earthquakes affects economic growth both across and within countries. The key result of the empirical analysis is that while there are no observable effects at the country level, earthquake exposure significantly decreases 5-year economic growth at the local level. Areas at lower stages of economic development suffer harder in terms of economic growth than richer areas. In addition,...

Retrospective stress-forecasting of earthquakes

Science.gov (United States)

Gao, Yuan; Crampin, Stuart

2015-04-01

Observations of changes in azimuthally varying shear-wave splitting (SWS) above swarms of small earthquakes monitor stress-induced changes to the stress-aligned vertical microcracks pervading the upper crust, lower crust, and uppermost ~400km of the mantle. (The microcracks are intergranular films of hydrolysed melt in the mantle.) Earthquakes release stress, and an appropriate amount of stress for the relevant magnitude must accumulate before each event. Iceland is on an extension of the Mid-Atlantic Ridge, where two transform zones, uniquely run onshore. These onshore transform zones provide semi-continuous swarms of small earthquakes, which are the only place worldwide where SWS can be routinely monitored. Elsewhere SWS must be monitored above temporally-active occasional swarms of small earthquakes, or in infrequent SKS and other teleseismic reflections from the mantle. Observations of changes in SWS time-delays are attributed to stress-induced changes in crack aspect-ratios allowing stress-accumulation and stress-relaxation to be identified. Monitoring SWS in SW Iceland in 1988, stress-accumulation before an impending earthquake was recognised and emails were exchanged between the University of Edinburgh (EU) and the Iceland Meteorological Office (IMO). On 10th November 1988, EU emailed IMO that a M5 earthquake could occur soon on a seismically-active fault plane where seismicity was still continuing following a M5.1 earthquake six-months earlier. Three-days later, IMO emailed EU that a M5 earthquake had just occurred on the specified fault-plane. We suggest this is a successful earthquake stress-forecast, where we refer to the procedure as stress-forecasting earthquakes as opposed to predicting or forecasting to emphasise the different formalism. Lack of funds has prevented us monitoring SWS on Iceland seismograms, however, we have identified similar characteristic behaviour of SWS time-delays above swarms of small earthquakes which have enabled us to

Charles Darwin's earthquake reports

Science.gov (United States)

Galiev, Shamil

2010-05-01

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

Organizational changes at Earthquakes & Volcanoes

Science.gov (United States)

Gordon, David W.

1992-01-01

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).

Earthquake effect on the geological environment

International Nuclear Information System (INIS)

Kawamura, Makoto

1999-01-01

Acceleration caused by the earthquake, changes in the water pressure, and the rock-mass strain were monitored for a series of 344 earthquakes from 1990 to 1998 at Kamaishi In Situ Test Site. The largest acceleration was registered to be 57.14 gal with the earthquake named 'North coast of Iwate Earthquake' (M4.4) occurred in June, 1996. Changes of the water pressure were recorded with 27 earthquakes; the largest change was -0.35 Kgt/cm 2 . The water-pressure change by earthquake was, however, usually smaller than that caused by rainfall in this area. No change in the electric conductivity or pH of ground water was detected before and after the earthquake throughout the entire period of monitoring. The rock-mass strain was measured with a extensometer whose detection limit was of the order of 10 -8 to 10 -9 degrees and the remaining strain of about 2.5x10 -9 degrees was detected following the 'Offshore Miyagi Earthquake' (M5.1) in October, 1997. (H. Baba)

Earthquake predictions using seismic velocity ratios

Science.gov (United States)

Sherburne, R. W.

1979-01-01

Since the beginning of modern seismology, seismologists have contemplated predicting earthquakes. The usefulness of earthquake predictions to the reduction of human and economic losses and the value of long-range earthquake prediction to planning is obvious. Not as clear are the long-range economic and social impacts of earthquake prediction to a speicifc area. The general consensus of opinion among scientists and government officials, however, is that the quest of earthquake prediction is a worthwhile goal and should be prusued with a sense of urgency. 

Earthquakes and Schools

Science.gov (United States)

National Clearinghouse for Educational Facilities, 2008

2008-01-01

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.…

Smoking prevalence increases following Canterbury earthquakes.

Science.gov (United States)

Erskine, Nick; Daley, Vivien; Stevenson, Sue; Rhodes, Bronwen; Beckert, Lutz

2013-01-01

A magnitude 7.1 earthquake hit Canterbury in September 2010. This earthquake and associated aftershocks took the lives of 185 people and drastically changed residents' living, working, and social conditions. To explore the impact of the earthquakes on smoking status and levels of tobacco consumption in the residents of Christchurch. Semistructured interviews were carried out in two city malls and the central bus exchange 15 months after the first earthquake. A total of 1001 people were interviewed. In August 2010, prior to any earthquake, 409 (41%) participants had never smoked, 273 (27%) were currently smoking, and 316 (32%) were ex-smokers. Since the September 2010 earthquake, 76 (24%) of the 316 ex-smokers had smoked at least one cigarette and 29 (38.2%) had smoked more than 100 cigarettes. Of the 273 participants who were current smokers in August 2010, 93 (34.1%) had increased consumption following the earthquake, 94 (34.4%) had not changed, and 86 (31.5%) had decreased their consumption. 53 (57%) of the 93 people whose consumption increased reported that the earthquake and subsequent lifestyle changes as a reason to increase smoking. 24% of ex-smokers resumed smoking following the earthquake, resulting in increased smoking prevalence. Tobacco consumption levels increased in around one-third of current smokers.

Cyclic migration of weak earthquakes between Lunigiana earthquake of October 10, 1995 and Reggio Emilia earthquake of October 15, 1996 (Northern Italy)

Science.gov (United States)

di Giovambattista, R.; Tyupkin, Yu

The cyclic migration of weak earthquakes (M 2.2) which occurred during the yearprior to the October 15, 1996 (M = 4.9) Reggio Emilia earthquake isdiscussed in this paper. The onset of this migration was associated with theoccurrence of the October 10, 1995 (M = 4.8) Lunigiana earthquakeabout 90 km southwest from the epicenter of the Reggio Emiliaearthquake. At least three series of earthquakes migrating from theepicentral area of the Lunigiana earthquake in the northeast direction wereobserved. The migration of earthquakes of the first series terminated at adistance of about 30 km from the epicenter of the Reggio Emiliaearthquake. The earthquake migration of the other two series halted atabout 10 km from the Reggio Emilia epicenter. The average rate ofearthquake migration was about 200-300 km/year, while the time ofrecurrence of the observed cycles varied from 68 to 178 days. Weakearthquakes migrated along the transversal fault zones and sometimesjumped from one fault to another. A correlation between the migratingearthquakes and tidal variations is analysed. We discuss the hypothesis thatthe analyzed area is in a state of stress approaching the limit of thelong-term durability of crustal rocks and that the observed cyclic migrationis a result of a combination of a more or less regular evolution of tectonicand tidal variations.

The 2012 Mw5.6 earthquake in Sofia seismogenic zone - is it a slow earthquake

Science.gov (United States)

Raykova, Plamena; Solakov, Dimcho; Slavcheva, Krasimira; Simeonova, Stela; Aleksandrova, Irena

2017-04-01

Recently our understanding of tectonic faulting has been shaken by the discoveries of seismic tremor, low frequency earthquakes, slow slip events, and other models of fault slip. These phenomenas represent models of failure that were thought to be non-existent and theoretically impossible only a few years ago. Slow earthquakes are seismic phenomena in which the rupture of geological faults in the earth's crust occurs gradually without creating strong tremors. Despite the growing number of observations of slow earthquakes their origin remains unresolved. Studies show that the duration of slow earthquakes ranges from a few seconds to a few hundred seconds. The regular earthquakes with which most people are familiar release a burst of built-up stress in seconds, slow earthquakes release energy in ways that do little damage. This study focus on the characteristics of the Mw5.6 earthquake occurred in Sofia seismic zone on May 22nd, 2012. The Sofia area is the most populated, industrial and cultural region of Bulgaria that faces considerable earthquake risk. The Sofia seismic zone is located in South-western Bulgaria - the area with pronounce tectonic activity and proved crustal movement. In 19th century the city of Sofia (situated in the centre of the Sofia seismic zone) has experienced two strong earthquakes with epicentral intensity of 10 MSK. During the 20th century the strongest event occurred in the vicinity of the city of Sofia is the 1917 earthquake with MS=5.3 (I0=7-8 MSK64).The 2012 quake occurs in an area characterized by a long quiescence (of 95 years) for moderate events. Moreover, a reduced number of small earthquakes have also been registered in the recent past. The Mw5.6 earthquake is largely felt on the territory of Bulgaria and neighbouring countries. No casualties and severe injuries have been reported. Mostly moderate damages were observed in the cities of Pernik and Sofia and their surroundings. These observations could be assumed indicative for a

The severity of an earthquake

Science.gov (United States)

,

1997-01-01

The severity of an earthquake can be expressed in terms of both intensity and magnitude. However, the two terms are quite different, and they are often confused. Intensity is based on the observed effects of ground shaking on people, buildings, and natural features. It varies from place to place within the disturbed region depending on the location of the observer with respect to the earthquake epicenter. Magnitude is related to the amount of seismic energy released at the hypocenter of the earthquake. It is based on the amplitude of the earthquake waves recorded on instruments

Thoracic Injuries in earthquake-related versus non-earthquake-related trauma patients: differentiation via Multi-detector Computed Tomography

Directory of Open Access Journals (Sweden)

Zhi-hui Dong

2011-01-01

Full Text Available PURPOSE: Massive earthquakes are harmful to humankind. This study of a historical cohort aimed to investigate the difference between earthquake-related crush thoracic traumas and thoracic traumas unrelated to earthquakes using a multi-detector Computed Tomography (CT. METHODS: We retrospectively compared an earthquake-exposed cohort of 215 thoracic trauma crush victims of the Sichuan earthquake to a cohort of 215 non-earthquake-related thoracic trauma patients, focusing on the lesions and coexisting injuries to the thoracic cage and the pulmonary parenchyma and pleura using a multi-detector CT. RESULTS: The incidence of rib fracture was elevated in the earthquake-exposed cohort (143 vs. 66 patients in the non-earthquake-exposed cohort, Risk Ratio (RR = 2.2; p<0.001. Among these patients, those with more than 3 fractured ribs (106/143 vs. 41/66 patients, RR=1.2; p<0.05 or flail chest (45/143 vs. 11/66 patients, RR=1.9; p<0.05 were more frequently seen in the earthquake cohort. Earthquake-related crush injuries more frequently resulted in bilateral rib fractures (66/143 vs. 18/66 patients, RR= 1.7; p<0.01. Additionally, the incidence of non-rib fracture was higher in the earthquake cohort (85 vs. 60 patients, RR= 1.4; p<0.01. Pulmonary parenchymal and pleural injuries were more frequently seen in earthquake-related crush injuries (117 vs. 80 patients, RR=1.5 for parenchymal and 146 vs. 74 patients, RR = 2.0 for pleural injuries; p<0.001. Non-rib fractures, pulmonary parenchymal and pleural injuries had significant positive correlation with rib fractures in these two cohorts. CONCLUSIONS: Thoracic crush traumas resulting from the earthquake were life threatening with a high incidence of bony thoracic fractures. The ribs were frequently involved in bilateral and severe types of fractures, which were accompanied by non-rib fractures, pulmonary parenchymal and pleural injuries.

Earthquake prediction by Kina Method

International Nuclear Information System (INIS)

Kianoosh, H.; Keypour, H.; Naderzadeh, A.; Motlagh, H.F.

2005-01-01

Earthquake prediction has been one of the earliest desires of the man. Scientists have worked hard to predict earthquakes for a long time. The results of these efforts can generally be divided into two methods of prediction: 1) Statistical Method, and 2) Empirical Method. In the first method, earthquakes are predicted using statistics and probabilities, while the second method utilizes variety of precursors for earthquake prediction. The latter method is time consuming and more costly. However, the result of neither method has fully satisfied the man up to now. In this paper a new method entitled 'Kiana Method' is introduced for earthquake prediction. This method offers more accurate results yet lower cost comparing to other conventional methods. In Kiana method the electrical and magnetic precursors are measured in an area. Then, the time and the magnitude of an earthquake in the future is calculated using electrical, and in particular, electrical capacitors formulas. In this method, by daily measurement of electrical resistance in an area we make clear that the area is capable of earthquake occurrence in the future or not. If the result shows a positive sign, then the occurrence time and the magnitude can be estimated by the measured quantities. This paper explains the procedure and details of this prediction method. (authors)

Sense of Community and Depressive Symptoms among Older Earthquake Survivors Following the 2008 Earthquake in Chengdu China

Science.gov (United States)

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

2011-01-01

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…

Precisely locating the Klamath Falls, Oregon, earthquakes

Science.gov (United States)

Qamar, A.; Meagher, K.L.

1993-01-01

The Klamath Falls earthquakes on September 20, 1993, were the largest earthquakes centered in Oregon in more than 50 yrs. Only the magnitude 5.75 Milton-Freewater earthquake in 1936, which was centered near the Oregon-Washington border and felt in an area of about 190,000 sq km, compares in size with the recent Klamath Falls earthquakes. Although the 1993 earthquakes surprised many local residents, geologists have long recognized that strong earthquakes may occur along potentially active faults that pass through the Klamath Falls area. These faults are geologically related to similar faults in Oregon, Idaho, and Nevada that occasionally spawn strong earthquakes. 

The mechanism of earthquake

Science.gov (United States)

Lu, Kunquan; Cao, Zexian; Hou, Meiying; Jiang, Zehui; Shen, Rong; Wang, Qiang; Sun, Gang; Liu, Jixing

2018-03-01

The physical mechanism of earthquake remains a challenging issue to be clarified. Seismologists used to attribute shallow earthquake to the elastic rebound of crustal rocks. The seismic energy calculated following the elastic rebound theory and with the data of experimental results upon rocks, however, shows a large discrepancy with measurement — a fact that has been dubbed as “the heat flow paradox”. For the intermediate-focus and deep-focus earthquakes, both occurring in the region of the mantle, there is not reasonable explanation either. This paper will discuss the physical mechanism of earthquake from a new perspective, starting from the fact that both the crust and the mantle are discrete collective system of matters with slow dynamics, as well as from the basic principles of physics, especially some new concepts of condensed matter physics emerged in the recent years. (1) Stress distribution in earth’s crust: Without taking the tectonic force into account, according to the rheological principle of “everything flows”, the normal stress and transverse stress must be balanced due to the effect of gravitational pressure over a long period of time, thus no differential stress in the original crustal rocks is to be expected. The tectonic force is successively transferred and accumulated via stick-slip motions of rock blocks to squeeze the fault gouge and then exerted upon other rock blocks. The superposition of such additional lateral tectonic force and the original stress gives rise to the real-time stress in crustal rocks. The mechanical characteristics of fault gouge are different from rocks as it consists of granular matters. The elastic moduli of the fault gouges are much less than those of rocks, and they become larger with increasing pressure. This peculiarity of the fault gouge leads to a tectonic force increasing with depth in a nonlinear fashion. The distribution and variation of the tectonic stress in the crust are specified. (2) The

Turkish Children's Ideas about Earthquakes

Science.gov (United States)

Simsek, Canan Lacin

2007-01-01

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…

Large earthquakes and creeping faults

Science.gov (United States)

Harris, Ruth A.

2017-01-01

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.

Global earthquake fatalities and population

Science.gov (United States)

Holzer, Thomas L.; Savage, James C.

2013-01-01

Modern global earthquake fatalities can be separated into two components: (1) fatalities from an approximately constant annual background rate that is independent of world population growth and (2) fatalities caused by earthquakes with large human death tolls, the frequency of which is dependent on world population. Earthquakes with death tolls greater than 100,000 (and 50,000) have increased with world population and obey a nonstationary Poisson distribution with rate proportional to population. We predict that the number of earthquakes with death tolls greater than 100,000 (50,000) will increase in the 21st century to 8.7±3.3 (20.5±4.3) from 4 (7) observed in the 20th century if world population reaches 10.1 billion in 2100. Combining fatalities caused by the background rate with fatalities caused by catastrophic earthquakes (>100,000 fatalities) indicates global fatalities in the 21st century will be 2.57±0.64 million if the average post-1900 death toll for catastrophic earthquakes (193,000) is assumed.

Instruction system upon occurrence of earthquakes

International Nuclear Information System (INIS)

Inagaki, Masakatsu; Morikawa, Matsuo; Suzuki, Satoshi; Fukushi, Naomi.

1987-01-01

Purpose: To enable rapid re-starting of a nuclear reactor after earthquakes by informing various properties of encountered earthquake to operators and properly displaying the state of damages in comparison with designed standard values of facilities. Constitution: Even in a case where the maximum accelerations due to the movements of earthquakes encountered exceed designed standard values, it may be considered such a case that equipments still remain intact depending on the wave components of the seismic movements and the vibration properties inherent to the equipments. Taking notice of the fact, the instruction device comprises a system that indicates the relationship between the seismic waveforms of earthquakes being encountered and the scram setting values, a system for indicating the comparison between the floor response spectrum of the seismic waveforms of the encountered earthquakes and the designed floor response spectrum used for the design of the equipments and a system for indicating those equipments requiring inspection after the earthquakes. Accordingly, it is possible to improve the operationability upon scram of a nuclear power plant undergoing earthquakes and improve the power saving and safety by clearly defining the inspection portion after the earthquakes. (Kawakami, Y.)

How fault geometry controls earthquake magnitude

Science.gov (United States)

Bletery, Q.; Thomas, A.; Karlstrom, L.; Rempel, A. W.; Sladen, A.; De Barros, L.

2016-12-01

Recent large megathrust earthquakes, such as the Mw9.3 Sumatra-Andaman earthquake in 2004 and the Mw9.0 Tohoku-Oki earthquake in 2011, astonished the scientific community. The first event occurred in a relatively low-convergence-rate subduction zone where events of its size were unexpected. The second event involved 60 m of shallow slip in a region thought to be aseismicaly creeping and hence incapable of hosting very large magnitude earthquakes. These earthquakes highlight gaps in our understanding of mega-earthquake rupture processes and the factors controlling their global distribution. Here we show that gradients in dip angle exert a primary control on mega-earthquake occurrence. We calculate the curvature along the major subduction zones of the world and show that past mega-earthquakes occurred on flat (low-curvature) interfaces. A simplified analytic model demonstrates that shear strength heterogeneity increases with curvature. Stress loading on flat megathrusts is more homogeneous and hence more likely to be released simultaneously over large areas than on highly-curved faults. Therefore, the absence of asperities on large faults might counter-intuitively be a source of higher hazard.

Earthquake casualty models within the USGS Prompt Assessment of Global Earthquakes for Response (PAGER) system

Science.gov (United States)

Jaiswal, Kishor; Wald, David J.; Earle, Paul S.; Porter, Keith A.; Hearne, Mike

2011-01-01

Since the launch of the USGS’s Prompt Assessment of Global Earthquakes for Response (PAGER) system in fall of 2007, the time needed for the U.S. Geological Survey (USGS) to determine and comprehend the scope of any major earthquake disaster anywhere in the world has been dramatically reduced to less than 30 min. PAGER alerts consist of estimated shaking hazard from the ShakeMap system, estimates of population exposure at various shaking intensities, and a list of the most severely shaken cities in the epicentral area. These estimates help government, scientific, and relief agencies to guide their responses in the immediate aftermath of a significant earthquake. To account for wide variability and uncertainty associated with inventory, structural vulnerability and casualty data, PAGER employs three different global earthquake fatality/loss computation models. This article describes the development of the models and demonstrates the loss estimation capability for earthquakes that have occurred since 2007. The empirical model relies on country-specific earthquake loss data from past earthquakes and makes use of calibrated casualty rates for future prediction. The semi-empirical and analytical models are engineering-based and rely on complex datasets including building inventories, time-dependent population distributions within different occupancies, the vulnerability of regional building stocks, and casualty rates given structural collapse.

Measuring the size of an earthquake

Science.gov (United States)

Spence, W.; Sipkin, S.A.; Choy, G.L.

1989-01-01

Earthquakes range broadly in size. A rock-burst in an Idaho silver mine may involve the fracture of 1 meter of rock; the 1965 Rat Island earthquake in the Aleutian arc involved a 650-kilometer length of the Earth's crust. Earthquakes can be even smaller and even larger. If an earthquake is felt or causes perceptible surface damage, then its intensity of shaking can be subjectively estimated. But many large earthquakes occur in oceanic areas or at great focal depths and are either simply not felt or their felt pattern does not really indicate their true size.

Earthquakes-Rattling the Earth's Plumbing System

Science.gov (United States)

Sneed, Michelle; Galloway, Devin L.; Cunningham, William L.

2003-01-01

Hydrogeologic responses to earthquakes have been known for decades, and have occurred both close to, and thousands of miles from earthquake epicenters. Water wells have become turbid, dry or begun flowing, discharge of springs and ground water to streams has increased and new springs have formed, and well and surface-water quality have become degraded as a result of earthquakes. Earthquakes affect our Earth’s intricate plumbing system—whether you live near the notoriously active San Andreas Fault in California, or far from active faults in Florida, an earthquake near or far can affect you and the water resources you depend on.

Real-time earthquake source imaging: An offline test for the 2011 Tohoku earthquake

Science.gov (United States)

Zhang, Yong; Wang, Rongjiang; Zschau, Jochen; Parolai, Stefano; Dahm, Torsten

2014-05-01

In recent decades, great efforts have been expended in real-time seismology aiming at earthquake and tsunami early warning. One of the most important issues is the real-time assessment of earthquake rupture processes using near-field seismogeodetic networks. Currently, earthquake early warning systems are mostly based on the rapid estimate of P-wave magnitude, which contains generally large uncertainties and the known saturation problem. In the case of the 2011 Mw9.0 Tohoku earthquake, JMA (Japan Meteorological Agency) released the first warning of the event with M7.2 after 25 s. The following updates of the magnitude even decreased to M6.3-6.6. Finally, the magnitude estimate stabilized at M8.1 after about two minutes. This led consequently to the underestimated tsunami heights. By using the newly developed Iterative Deconvolution and Stacking (IDS) method for automatic source imaging, we demonstrate an offline test for the real-time analysis of the strong-motion and GPS seismograms of the 2011 Tohoku earthquake. The results show that we had been theoretically able to image the complex rupture process of the 2011 Tohoku earthquake automatically soon after or even during the rupture process. In general, what had happened on the fault could be robustly imaged with a time delay of about 30 s by using either the strong-motion (KiK-net) or the GPS (GEONET) real-time data. This implies that the new real-time source imaging technique is helpful to reduce false and missing warnings, and therefore should play an important role in future tsunami early warning and earthquake rapid response systems.

Earthquake forewarning in the Cascadia region

Science.gov (United States)

Gomberg, Joan S.; Atwater, Brian F.; Beeler, Nicholas M.; Bodin, Paul; Davis, Earl; Frankel, Arthur; Hayes, Gavin P.; McConnell, Laura; Melbourne, Tim; Oppenheimer, David H.; Parrish, John G.; Roeloffs, Evelyn A.; Rogers, Gary D.; Sherrod, Brian; Vidale, John; Walsh, Timothy J.; Weaver, Craig S.; Whitmore, Paul M.

2015-08-10

This report, prepared for the National Earthquake Prediction Evaluation Council (NEPEC), is intended as a step toward improving communications about earthquake hazards between information providers and users who coordinate emergency-response activities in the Cascadia region of the Pacific Northwest. NEPEC charged a subcommittee of scientists with writing this report about forewarnings of increased probabilities of a damaging earthquake. We begin by clarifying some terminology; a “prediction” refers to a deterministic statement that a particular future earthquake will or will not occur. In contrast to the 0- or 100-percent likelihood of a deterministic prediction, a “forecast” describes the probability of an earthquake occurring, which may range from >0 to processes or conditions, which may include Increased rates of M>4 earthquakes on the plate interface north of the Mendocino region 

Links Between Earthquake Characteristics and Subducting Plate Heterogeneity in the 2016 Pedernales Ecuador Earthquake Rupture Zone

Science.gov (United States)

Bai, L.; Mori, J. J.

2016-12-01

The collision between the Indian and Eurasian plates formed the Himalayas, the largest orogenic belt on the Earth. The entire region accommodates shallow earthquakes, while intermediate-depth earthquakes are concentrated at the eastern and western Himalayan syntaxis. Here we investigate the focal depths, fault plane solutions, and source rupture process for three earthquake sequences, which are located at the western, central and eastern regions of the Himalayan orogenic belt. The Pamir-Hindu Kush region is located at the western Himalayan syntaxis and is characterized by extreme shortening of the upper crust and strong interaction of various layers of the lithosphere. Many shallow earthquakes occur on the Main Pamir Thrust at focal depths shallower than 20 km, while intermediate-deep earthquakes are mostly located below 75 km. Large intermediate-depth earthquakes occur frequently at the western Himalayan syntaxis about every 10 years on average. The 2015 Nepal earthquake is located in the central Himalayas. It is a typical megathrust earthquake that occurred on the shallow portion of the Main Himalayan Thrust (MHT). Many of the aftershocks are located above the MHT and illuminate faulting structures in the hanging wall with dip angles that are steeper than the MHT. These observations provide new constraints on the collision and uplift processes for the Himalaya orogenic belt. The Indo-Burma region is located south of the eastern Himalayan syntaxis, where the strike of the plate boundary suddenly changes from nearly east-west at the Himalayas to nearly north-south at the Burma Arc. The Burma arc subduction zone is a typical oblique plate convergence zone. The eastern boundary is the north-south striking dextral Sagaing fault, which hosts many shallow earthquakes with focal depth less than 25 km. In contrast, intermediate-depth earthquakes along the subduction zone reflect east-west trending reverse faulting.

Earthquakes; May-June 1982

Science.gov (United States)

Person, W.J.

1982-01-01

There were four major earthquakes (7.0-7.9) during this reporting period: two struck in Mexico, one in El Salvador, and one in teh Kuril Islands. Mexico, El Salvador, and China experienced fatalities from earthquakes.

Radon observation for earthquake prediction

Energy Technology Data Exchange (ETDEWEB)

Wakita, Hiroshi [Tokyo Univ. (Japan)

1998-12-31

Systematic observation of groundwater radon for the purpose of earthquake prediction began in Japan in late 1973. Continuous observations are conducted at fixed stations using deep wells and springs. During the observation period, significant precursory changes including the 1978 Izu-Oshima-kinkai (M7.0) earthquake as well as numerous coseismic changes were observed. At the time of the 1995 Kobe (M7.2) earthquake, significant changes in chemical components, including radon dissolved in groundwater, were observed near the epicentral region. Precursory changes are presumably caused by permeability changes due to micro-fracturing in basement rock or migration of water from different sources during the preparation stage of earthquakes. Coseismic changes may be caused by seismic shaking and by changes in regional stress. Significant drops of radon concentration in groundwater have been observed after earthquakes at the KSM site. The occurrence of such drops appears to be time-dependent, and possibly reflects changes in the regional stress state of the observation area. The absence of radon drops seems to be correlated with periods of reduced regional seismic activity. Experience accumulated over the two past decades allows us to reach some conclusions: 1) changes in groundwater radon do occur prior to large earthquakes; 2) some sites are particularly sensitive to earthquake occurrence; and 3) the sensitivity changes over time. (author)

Earthquake number forecasts testing

Science.gov (United States)

Kagan, Yan Y.

2017-10-01

We study the distributions of earthquake numbers in two global earthquake catalogues: Global Centroid-Moment Tensor and Preliminary Determinations of Epicenters. The properties of these distributions are especially required to develop the number test for our forecasts of future seismic activity rate, tested by the Collaboratory for Study of Earthquake Predictability (CSEP). A common assumption, as used in the CSEP tests, is that the numbers are described by the Poisson distribution. It is clear, however, that the Poisson assumption for the earthquake number distribution is incorrect, especially for the catalogues with a lower magnitude threshold. In contrast to the one-parameter Poisson distribution so widely used to describe earthquake occurrences, the negative-binomial distribution (NBD) has two parameters. The second parameter can be used to characterize the clustering or overdispersion of a process. We also introduce and study a more complex three-parameter beta negative-binomial distribution. We investigate the dependence of parameters for both Poisson and NBD distributions on the catalogue magnitude threshold and on temporal subdivision of catalogue duration. First, we study whether the Poisson law can be statistically rejected for various catalogue subdivisions. We find that for most cases of interest, the Poisson distribution can be shown to be rejected statistically at a high significance level in favour of the NBD. Thereafter, we investigate whether these distributions fit the observed distributions of seismicity. For this purpose, we study upper statistical moments of earthquake numbers (skewness and kurtosis) and compare them to the theoretical values for both distributions. Empirical values for the skewness and the kurtosis increase for the smaller magnitude threshold and increase with even greater intensity for small temporal subdivision of catalogues. The Poisson distribution for large rate values approaches the Gaussian law, therefore its skewness

33 CFR 222.4 - Reporting earthquake effects.

Science.gov (United States)

2010-07-01

... 33 Navigation and Navigable Waters 3 2010-07-01 2010-07-01 false Reporting earthquake effects. 222..., DEPARTMENT OF DEFENSE ENGINEERING AND DESIGN § 222.4 Reporting earthquake effects. (a) Purpose. This... significant earthquakes. It primarily concerns damage surveys following the occurrences of earthquakes. (b...

Earthquakes - a danger to deep-lying repositories?

International Nuclear Information System (INIS)

2012-03-01

This booklet issued by the Swiss National Cooperative for the Disposal of Radioactive Waste NAGRA takes a look at geological factors concerning earthquakes and the safety of deep-lying repositories for nuclear waste. The geological processes involved in the occurrence of earthquakes are briefly looked at and the definitions for magnitude and intensity of earthquakes are discussed. Examples of damage caused by earthquakes are given. The earthquake situation in Switzerland is looked at and the effects of earthquakes on sub-surface structures and deep-lying repositories are discussed. Finally, the ideas proposed for deep-lying geological repositories for nuclear wastes are discussed

Evidence for Ancient Mesoamerican Earthquakes

Science.gov (United States)

Kovach, R. L.; Garcia, B.

2001-12-01

Evidence for past earthquake damage at Mesoamerican ruins is often overlooked because of the invasive effects of tropical vegetation and is usually not considered as a casual factor when restoration and reconstruction of many archaeological sites are undertaken. Yet the proximity of many ruins to zones of seismic activity would argue otherwise. Clues as to the types of damage which should be soughtwere offered in September 1999 when the M = 7.5 Oaxaca earthquake struck the ruins of Monte Alban, Mexico, where archaeological renovations were underway. More than 20 structures were damaged, 5 of them seriously. Damage features noted were walls out of plumb, fractures in walls, floors, basal platforms and tableros, toppling of columns, and deformation, settling and tumbling of walls. A Modified Mercalli Intensity of VII (ground accelerations 18-34 %b) occurred at the site. Within the diffuse landward extension of the Caribbean plate boundary zone M = 7+ earthquakes occur with repeat times of hundreds of years arguing that many Maya sites were subjected to earthquakes. Damage to re-erected and reinforced stelae, walls, and buildings were witnessed at Quirigua, Guatemala, during an expedition underway when then 1976 M = 7.5 Guatemala earthquake on the Motagua fault struck. Excavations also revealed evidence (domestic pttery vessels and skeleton of a child crushed under fallen walls) of an ancient earthquake occurring about the teim of the demise and abandonment of Quirigua in the late 9th century. Striking evidence for sudden earthquake building collapse at the end of the Mayan Classic Period ~A.D. 889 was found at Benque Viejo (Xunantunich), Belize, located 210 north of Quirigua. It is argued that a M = 7.5 to 7.9 earthquake at the end of the Maya Classic period centered in the vicinity of the Chixoy-Polochic and Motagua fault zones cound have produced the contemporaneous earthquake damage to the above sites. As a consequences this earthquake may have accelerated the

Earthquake data base for Romania

International Nuclear Information System (INIS)

Rizescu, M.; Ghica, D.; Grecu, B.; Popa, M.; Borcia, I. S.

2002-01-01

A new earthquake database for Romania is being constructed, comprising complete earthquake information and being up-to-date, user-friendly and rapidly accessible. One main component of the database consists from the catalog of earthquakes occurred in Romania since 984 up to present. The catalog contains information related to locations and other source parameters, when available, and links to waveforms of important earthquakes. The other very important component is the 'strong motion database', developed for strong intermediate-depth Vrancea earthquakes where instrumental data were recorded. Different parameters to characterize strong motion properties as: effective peak acceleration, effective peak velocity, corner periods T c and T d , global response spectrum based intensities were computed and recorded into this database. Also, information on the recording seismic stations as: maps giving their positioning, photographs of the instruments and site conditions ('free-field or on buildings) are included. By the huge volume and quality of gathered data, also by its friendly user interface, the Romania earthquake data base provides a very useful tool for geosciences and civil engineering in their effort towards reducing seismic risk in Romania. (authors)

Mapping Tectonic Stress Using Earthquakes

International Nuclear Information System (INIS)

Arnold, Richard; Townend, John; Vignaux, Tony

2005-01-01

An earthquakes occurs when the forces acting on a fault overcome its intrinsic strength and cause it to slip abruptly. Understanding more specifically why earthquakes occur at particular locations and times is complicated because in many cases we do not know what these forces actually are, or indeed what processes ultimately trigger slip. The goal of this study is to develop, test, and implement a Bayesian method of reliably determining tectonic stresses using the most abundant stress gauges available - earthquakes themselves.Existing algorithms produce reasonable estimates of the principal stress directions, but yield unreliable error bounds as a consequence of the generally weak constraint on stress imposed by any single earthquake, observational errors, and an unavoidable ambiguity between the fault normal and the slip vector.A statistical treatment of the problem can take into account observational errors, combine data from multiple earthquakes in a consistent manner, and provide realistic error bounds on the estimated principal stress directions.We have developed a realistic physical framework for modelling multiple earthquakes and show how the strong physical and geometrical constraints present in this problem allow inference to be made about the orientation of the principal axes of stress in the earth's crust

Testing earthquake source inversion methodologies

KAUST Repository

Page, Morgan T.

2011-01-01

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.

Earthquake cycles and physical modeling of the process leading up to a large earthquake

Science.gov (United States)

Ohnaka, Mitiyasu

2004-08-01

A thorough discussion is made on what the rational constitutive law for earthquake ruptures ought to be from the standpoint of the physics of rock friction and fracture on the basis of solid facts observed in the laboratory. From this standpoint, it is concluded that the constitutive law should be a slip-dependent law with parameters that may depend on slip rate or time. With the long-term goal of establishing a rational methodology of forecasting large earthquakes, the entire process of one cycle for a typical, large earthquake is modeled, and a comprehensive scenario that unifies individual models for intermediate-and short-term (immediate) forecasts is presented within the framework based on the slip-dependent constitutive law and the earthquake cycle model. The earthquake cycle includes the phase of accumulation of elastic strain energy with tectonic loading (phase II), and the phase of rupture nucleation at the critical stage where an adequate amount of the elastic strain energy has been stored (phase III). Phase II plays a critical role in physical modeling of intermediate-term forecasting, and phase III in physical modeling of short-term (immediate) forecasting. The seismogenic layer and individual faults therein are inhomogeneous, and some of the physical quantities inherent in earthquake ruptures exhibit scale-dependence. It is therefore critically important to incorporate the properties of inhomogeneity and physical scaling, in order to construct realistic, unified scenarios with predictive capability. The scenario presented may be significant and useful as a necessary first step for establishing the methodology for forecasting large earthquakes.

The USGS Earthquake Notification Service (ENS): Customizable notifications of earthquakes around the globe

Science.gov (United States)

Wald, Lisa A.; Wald, David J.; Schwarz, Stan; Presgrave, Bruce; Earle, Paul S.; Martinez, Eric; Oppenheimer, David

2008-01-01

At the beginning of 2006, the U.S. Geological Survey (USGS) Earthquake Hazards Program (EHP) introduced a new automated Earthquake Notification Service (ENS) to take the place of the National Earthquake Information Center (NEIC) "Bigquake" system and the various other individual EHP e-mail list-servers for separate regions in the United States. These included northern California, southern California, and the central and eastern United States. ENS is a "one-stop shopping" system that allows Internet users to subscribe to flexible and customizable notifications for earthquakes anywhere in the world. The customization capability allows users to define the what (magnitude threshold), the when (day and night thresholds), and the where (specific regions) for their notifications. Customization is achieved by employing a per-user based request profile, allowing the notifications to be tailored for each individual's requirements. Such earthquake-parameter-specific custom delivery was not possible with simple e-mail list-servers. Now that event and user profiles are in a structured query language (SQL) database, additional flexibility is possible. At the time of this writing, ENS had more than 114,000 subscribers, with more than 200,000 separate user profiles. On a typical day, more than 188,000 messages get sent to a variety of widely distributed users for a wide range of earthquake locations and magnitudes. The purpose of this article is to describe how ENS works, highlight the features it offers, and summarize plans for future developments.

Stigma in science: the case of earthquake prediction.

Science.gov (United States)

Joffe, Helene; Rossetto, Tiziana; Bradley, Caroline; O'Connor, Cliodhna

2018-01-01

This paper explores how earthquake scientists conceptualise earthquake prediction, particularly given the conviction of six earthquake scientists for manslaughter (subsequently overturned) on 22 October 2012 for having given inappropriate advice to the public prior to the L'Aquila earthquake of 6 April 2009. In the first study of its kind, semi-structured interviews were conducted with 17 earthquake scientists and the transcribed interviews were analysed thematically. The scientists primarily denigrated earthquake prediction, showing strong emotive responses and distancing themselves from earthquake 'prediction' in favour of 'forecasting'. Earthquake prediction was regarded as impossible and harmful. The stigmatisation of the subject is discussed in the light of research on boundary work and stigma in science. The evaluation reveals how mitigation becomes the more favoured endeavour, creating a normative environment that disadvantages those who continue to pursue earthquake prediction research. Recommendations are made for communication with the public on earthquake risk, with a focus on how scientists portray uncertainty. © 2018 The Author(s). Disasters © Overseas Development Institute, 2018.

Impact of the Christchurch earthquakes on hospital staff.

Science.gov (United States)

Tovaranonte, Pleayo; Cawood, Tom J

2013-06-01

On September 4, 2010 a major earthquake caused widespread damage, but no loss of life, to Christchurch city and surrounding areas. There were numerous aftershocks, including on February 22, 2011 which, in contrast, caused substantial loss of life and major damage to the city. The research aim was to assess how these two earthquakes affected the staff in the General Medicine Department at Christchurch Hospital. Problem To date there have been no published data assessing the impact of this type of natural disaster on hospital staff in Australasia. A questionnaire that examined seven domains (demographics, personal impact, psychological impact, emotional impact, impact on care for patients, work impact, and coping strategies) was handed out to General Medicine staff and students nine days after the September 2010 earthquake and 14 days after the February 2011 earthquake. Response rates were ≥ 99%. Sixty percent of responders were earthquakes, respectively. A fifth to a third of people had to find an alternative route of transport to get to work but only eight percent to 18% took time off work. Financial impact was more severe following the February earthquake, with 46% reporting damage of >NZ $1,000, compared with 15% following the September earthquake (P earthquake than the September earthquake (42% vs 69%, P earthquake but this rose to 53% after the February earthquake (12/53 vs 45/85, P earthquake but this dropped significantly to 15% following the February earthquake (27/53 vs 13/62, P earthquakes upon General Medicine hospital staff. The effect was widespread with minor financial impact during the first but much more during the second earthquake. Moderate psychological impact was experienced in both earthquakes. This data may be useful to help prepare plans for future natural disasters. .

Physics of Earthquake Rupture Propagation

Science.gov (United States)

Xu, Shiqing; Fukuyama, Eiichi; Sagy, Amir; Doan, Mai-Linh

2018-05-01

A comprehensive understanding of earthquake rupture propagation requires the study of not only the sudden release of elastic strain energy during co-seismic slip, but also of other processes that operate at a variety of spatiotemporal scales. For example, the accumulation of the elastic strain energy usually takes decades to hundreds of years, and rupture propagation and termination modify the bulk properties of the surrounding medium that can influence the behavior of future earthquakes. To share recent findings in the multiscale investigation of earthquake rupture propagation, we held a session entitled "Physics of Earthquake Rupture Propagation" during the 2016 American Geophysical Union (AGU) Fall Meeting in San Francisco. The session included 46 poster and 32 oral presentations, reporting observations of natural earthquakes, numerical and experimental simulations of earthquake ruptures, and studies of earthquake fault friction. These presentations and discussions during and after the session suggested a need to document more formally the research findings, particularly new observations and views different from conventional ones, complexities in fault zone properties and loading conditions, the diversity of fault slip modes and their interactions, the evaluation of observational and model uncertainties, and comparison between empirical and physics-based models. Therefore, we organize this Special Issue (SI) of Tectonophysics under the same title as our AGU session, hoping to inspire future investigations. Eighteen articles (marked with "this issue") are included in this SI and grouped into the following six categories.

Real Time Earthquake Information System in Japan

Science.gov (United States)

Doi, K.; Kato, T.

2003-12-01

An early earthquake notification system in Japan had been developed by the Japan Meteorological Agency (JMA) as a governmental organization responsible for issuing earthquake information and tsunami forecasts. The system was primarily developed for prompt provision of a tsunami forecast to the public with locating an earthquake and estimating its magnitude as quickly as possible. Years after, a system for a prompt provision of seismic intensity information as indices of degrees of disasters caused by strong ground motion was also developed so that concerned governmental organizations can decide whether it was necessary for them to launch emergency response or not. At present, JMA issues the following kinds of information successively when a large earthquake occurs. 1) Prompt report of occurrence of a large earthquake and major seismic intensities caused by the earthquake in about two minutes after the earthquake occurrence. 2) Tsunami forecast in around three minutes. 3) Information on expected arrival times and maximum heights of tsunami waves in around five minutes. 4) Information on a hypocenter and a magnitude of the earthquake, the seismic intensity at each observation station, the times of high tides in addition to the expected tsunami arrival times in 5-7 minutes. To issue information above, JMA has established; - An advanced nationwide seismic network with about 180 stations for seismic wave observation and about 3,400 stations for instrumental seismic intensity observation including about 2,800 seismic intensity stations maintained by local governments, - Data telemetry networks via landlines and partly via a satellite communication link, - Real-time data processing techniques, for example, the automatic calculation of earthquake location and magnitude, the database driven method for quantitative tsunami estimation, and - Dissemination networks, via computer-to-computer communications and facsimile through dedicated telephone lines. JMA operationally

Earthquake precursory events around epicenters and local active faults; the cases of two inland earthquakes in Iran

Science.gov (United States)

Valizadeh Alvan, H.; Mansor, S.; Haydari Azad, F.

2012-12-01

The possibility of earthquake prediction in the frame of several days to few minutes before its occurrence has stirred interest among researchers, recently. Scientists believe that the new theories and explanations of the mechanism of this natural phenomenon are trustable and can be the basis of future prediction efforts. During the last thirty years experimental researches resulted in some pre-earthquake events which are now recognized as confirmed warning signs (precursors) of past known earthquakes. With the advances in in-situ measurement devices and data analysis capabilities and the emergence of satellite-based data collectors, monitoring the earth's surface is now a regular work. Data providers are supplying researchers from all over the world with high quality and validated imagery and non-imagery data. Surface Latent Heat Flux (SLHF) or the amount of energy exchange in the form of water vapor between the earth's surface and atmosphere has been frequently reported as an earthquake precursor during the past years. The accumulated stress in the earth's crust during the preparation phase of earthquakes is said to be the main cause of temperature anomalies weeks to days before the main event and subsequent shakes. Chemical and physical interactions in the presence of underground water lead to higher water evaporation prior to inland earthquakes. On the other hand, the leak of Radon gas occurred as rocks break during earthquake preparation causes the formation of airborne ions and higher Air Temperature (AT) prior to main event. Although co-analysis of direct and indirect observation for precursory events is considered as a promising method for future successful earthquake prediction, without proper and thorough knowledge about the geological setting, atmospheric factors and geodynamics of the earthquake-prone regions we will not be able to identify anomalies due to seismic activity in the earth's crust. Active faulting is a key factor in identification of the

Napa Earthquake impact on water systems

Science.gov (United States)

Wang, J.

2014-12-01

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.

Earthquake Hazard Analysis Methods: A Review

Science.gov (United States)

Sari, A. M.; Fakhrurrozi, A.

2018-02-01

One of natural disasters that have significantly impacted on risks and damage is an earthquake. World countries such as China, Japan, and Indonesia are countries located on the active movement of continental plates with more frequent earthquake occurrence compared to other countries. Several methods of earthquake hazard analysis have been done, for example by analyzing seismic zone and earthquake hazard micro-zonation, by using Neo-Deterministic Seismic Hazard Analysis (N-DSHA) method, and by using Remote Sensing. In its application, it is necessary to review the effectiveness of each technique in advance. Considering the efficiency of time and the accuracy of data, remote sensing is used as a reference to the assess earthquake hazard accurately and quickly as it only takes a limited time required in the right decision-making shortly after the disaster. Exposed areas and possibly vulnerable areas due to earthquake hazards can be easily analyzed using remote sensing. Technological developments in remote sensing such as GeoEye-1 provide added value and excellence in the use of remote sensing as one of the methods in the assessment of earthquake risk and damage. Furthermore, the use of this technique is expected to be considered in designing policies for disaster management in particular and can reduce the risk of natural disasters such as earthquakes in Indonesia.

Earthquake Drill using the Earthquake Early Warning System at an Elementary School

Science.gov (United States)

Oki, Satoko; Yazaki, Yoshiaki; Koketsu, Kazuki

2010-05-01

Japan frequently suffers from many kinds of disasters such as earthquakes, typhoons, floods, volcanic eruptions, and landslides. On average, we lose about 120 people a year due to natural hazards in this decade. Above all, earthquakes are noteworthy, since it may kill thousands of people in a moment like in Kobe in 1995. People know that we may have "a big one" some day as long as we live on this land and that what to do; retrofit houses, appliance heavy furniture to walls, add latches to kitchen cabinets, and prepare emergency packs. Yet most of them do not take the action, and result in the loss of many lives. It is only the victims that learn something from the earthquake, and it has never become the lore of the nations. One of the most essential ways to reduce the damage is to educate the general public to be able to make the sound decision on what to do at the moment when an earthquake hits. This will require the knowledge of the backgrounds of the on-going phenomenon. The Ministry of Education, Culture, Sports, Science and Technology (MEXT), therefore, offered for public subscription to choose several model areas to adopt scientific education to the local elementary schools. This presentation is the report of a year and half courses that we had at the model elementary school in Tokyo Metropolitan Area. The tectonic setting of this area is very complicated; there are the Pacific and Philippine Sea plates subducting beneath the North America and the Eurasia plates. The subduction of the Philippine Sea plate causes mega-thrust earthquakes such as the 1923 Kanto earthquake (M 7.9) making 105,000 fatalities. A magnitude 7 or greater earthquake beneath this area is recently evaluated to occur with a probability of 70 % in 30 years. This is of immediate concern for the devastating loss of life and property because the Tokyo urban region now has a population of 42 million and is the center of approximately 40 % of the nation's activities, which may cause great global

Book review: Earthquakes and water

Science.gov (United States)

Bekins, Barbara A.

2012-01-01

It is really nice to see assembled in one place a discussion of the documented and hypothesized hydrologic effects of earthquakes. The book is divided into chapters focusing on particular hydrologic phenomena including liquefaction, mud volcanism, stream discharge increases, groundwater level, temperature and chemical changes, and geyser period changes. These hydrologic effects are inherently fascinating, and the large number of relevant publications in the past decade makes this summary a useful milepost. The book also covers hydrologic precursors and earthquake triggering by pore pressure. A natural need to limit the topics covered resulted in the omission of tsunamis and the vast literature on the role of fluids and pore pressure in frictional strength of faults. Regardless of whether research on earthquake-triggered hydrologic effects ultimately provides insight into the physics of earthquakes, the text provides welcome common ground for interdisciplinary collaborations between hydrologists and seismologists. Such collaborations continue to be crucial for investigating hypotheses about the role of fluids in earthquakes and slow slip. 

Earthquake resistant design of structures

International Nuclear Information System (INIS)

Choi, Chang Geun; Kim, Gyu Seok; Lee, Dong Geun

1990-02-01

This book tells of occurrence of earthquake and damage analysis of earthquake, equivalent static analysis method, application of equivalent static analysis method, dynamic analysis method like time history analysis by mode superposition method and direct integration method, design spectrum analysis considering an earthquake-resistant design in Korea. Such as analysis model and vibration mode, calculation of base shear, calculation of story seismic load and combine of analysis results.

Exploring Earthquakes in Real-Time

Science.gov (United States)

Bravo, T. K.; Kafka, A. L.; Coleman, B.; Taber, J. J.

2013-12-01

Earthquakes capture the attention of students and inspire them to explore the Earth. Adding the ability to view and explore recordings of significant and newsworthy earthquakes in real-time makes the subject even more compelling. To address this opportunity, the Incorporated Research Institutions for Seismology (IRIS), in collaboration with Moravian College, developed ';jAmaSeis', a cross-platform application that enables students to access real-time earthquake waveform data. Students can watch as the seismic waves are recorded on their computer, and can be among the first to analyze the data from an earthquake. jAmaSeis facilitates student centered investigations of seismological concepts using either a low-cost educational seismograph or streamed data from other educational seismographs or from any seismic station that sends data to the IRIS Data Management System. After an earthquake, students can analyze the seismograms to determine characteristics of earthquakes such as time of occurrence, distance from the epicenter to the station, magnitude, and location. The software has been designed to provide graphical clues to guide students in the analysis and assist in their interpretations. Since jAmaSeis can simultaneously record up to three stations from anywhere on the planet, there are numerous opportunities for student driven investigations. For example, students can explore differences in the seismograms from different distances from an earthquake and compare waveforms from different azimuthal directions. Students can simultaneously monitor seismicity at a tectonic plate boundary and in the middle of the plate regardless of their school location. This can help students discover for themselves the ideas underlying seismic wave propagation, regional earthquake hazards, magnitude-frequency relationships, and the details of plate tectonics. The real-time nature of the data keeps the investigations dynamic, and offers students countless opportunities to explore.

Spatial Evaluation and Verification of Earthquake Simulators

Science.gov (United States)

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

2017-06-01

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.

Parallel Earthquake Simulations on Large-Scale Multicore Supercomputers

KAUST Repository

Wu, Xingfu

2011-01-01

Earthquakes are one of the most destructive natural hazards on our planet Earth. Hugh earthquakes striking offshore may cause devastating tsunamis, as evidenced by the 11 March 2011 Japan (moment magnitude Mw9.0) and the 26 December 2004 Sumatra (Mw9.1) earthquakes. Earthquake prediction (in terms of the precise time, place, and magnitude of a coming earthquake) is arguably unfeasible in the foreseeable future. To mitigate seismic hazards from future earthquakes in earthquake-prone areas, such as California and Japan, scientists have been using numerical simulations to study earthquake rupture propagation along faults and seismic wave propagation in the surrounding media on ever-advancing modern computers over past several decades. In particular, ground motion simulations for past and future (possible) significant earthquakes have been performed to understand factors that affect ground shaking in populated areas, and to provide ground shaking characteristics and synthetic seismograms for emergency preparation and design of earthquake-resistant structures. These simulation results can guide the development of more rational seismic provisions for leading to safer, more efficient, and economical50pt]Please provide V. Taylor author e-mail ID. structures in earthquake-prone regions.

Children's emotional experience two years after an earthquake: An exploration of knowledge of earthquakes and associated emotions.

Science.gov (United States)

Raccanello, Daniela; Burro, Roberto; Hall, Rob

2017-01-01

We explored whether and how the exposure to a natural disaster such as the 2012 Emilia Romagna earthquake affected the development of children's emotional competence in terms of understanding, regulating, and expressing emotions, after two years, when compared with a control group not exposed to the earthquake. We also examined the role of class level and gender. The sample included two groups of children (n = 127) attending primary school: The experimental group (n = 65) experienced the 2012 Emilia Romagna earthquake, while the control group (n = 62) did not. The data collection took place two years after the earthquake, when children were seven or ten-year-olds. Beyond assessing the children's understanding of emotions and regulating abilities with standardized instruments, we employed semi-structured interviews to explore their knowledge of earthquakes and associated emotions, and a structured task on the intensity of some target emotions. We applied Generalized Linear Mixed Models. Exposure to the earthquake did not influence the understanding and regulation of emotions. The understanding of emotions varied according to class level and gender. Knowledge of earthquakes, emotional language, and emotions associated with earthquakes were, respectively, more complex, frequent, and intense for children who had experienced the earthquake, and at increasing ages. Our data extend the generalizability of theoretical models on children's psychological functioning following disasters, such as the dose-response model and the organizational-developmental model for child resilience, and provide further knowledge on children's emotional resources related to natural disasters, as a basis for planning educational prevention programs.

13 CFR 120.174 - Earthquake hazards.

Science.gov (United States)

2010-01-01

... 13 Business Credit and Assistance 1 2010-01-01 2010-01-01 false Earthquake hazards. 120.174... Applying to All Business Loans Requirements Imposed Under Other Laws and Orders § 120.174 Earthquake..., the construction must conform with the “National Earthquake Hazards Reduction Program (“NEHRP...

Earthquake magnitude estimation using the τ c and P d method for earthquake early warning systems

Science.gov (United States)

Jin, Xing; Zhang, Hongcai; Li, Jun; Wei, Yongxiang; Ma, Qiang

2013-10-01

Earthquake early warning (EEW) systems are one of the most effective ways to reduce earthquake disaster. Earthquake magnitude estimation is one of the most important and also the most difficult parts of the entire EEW system. In this paper, based on 142 earthquake events and 253 seismic records that were recorded by the KiK-net in Japan, and aftershocks of the large Wenchuan earthquake in Sichuan, we obtained earthquake magnitude estimation relationships using the τ c and P d methods. The standard variances of magnitude calculation of these two formulas are ±0.65 and ±0.56, respectively. The P d value can also be used to estimate the peak ground motion of velocity, then warning information can be released to the public rapidly, according to the estimation results. In order to insure the stability and reliability of magnitude estimation results, we propose a compatibility test according to the natures of these two parameters. The reliability of the early warning information is significantly improved though this test.

Earthquake evaluation of a substation network

International Nuclear Information System (INIS)

Matsuda, E.N.; Savage, W.U.; Williams, K.K.; Laguens, G.C.

1991-01-01

The impact of the occurrence of a large, damaging earthquake on a regional electric power system is a function of the geographical distribution of strong shaking, the vulnerability of various types of electric equipment located within the affected region, and operational resources available to maintain or restore electric system functionality. Experience from numerous worldwide earthquake occurrences has shown that seismic damage to high-voltage substation equipment is typically the reason for post-earthquake loss of electric service. In this paper, the authors develop and apply a methodology to analyze earthquake impacts on Pacific Gas and Electric Company's (PG and E's) high-voltage electric substation network in central and northern California. The authors' objectives are to identify and prioritize ways to reduce the potential impact of future earthquakes on our electric system, refine PG and E's earthquake preparedness and response plans to be more realistic, and optimize seismic criteria for future equipment purchases for the electric system

Update earthquake risk assessment in Cairo, Egypt

Science.gov (United States)

Badawy, Ahmed; Korrat, Ibrahim; El-Hadidy, Mahmoud; Gaber, Hanan

2017-07-01

The Cairo earthquake (12 October 1992; m b = 5.8) is still and after 25 years one of the most painful events and is dug into the Egyptians memory. This is not due to the strength of the earthquake but due to the accompanied losses and damages (561 dead; 10,000 injured and 3000 families lost their homes). Nowadays, the most frequent and important question that should rise is "what if this earthquake is repeated today." In this study, we simulate the same size earthquake (12 October 1992) ground motion shaking and the consequent social-economic impacts in terms of losses and damages. Seismic hazard, earthquake catalogs, soil types, demographics, and building inventories were integrated into HAZUS-MH to produce a sound earthquake risk assessment for Cairo including economic and social losses. Generally, the earthquake risk assessment clearly indicates that "the losses and damages may be increased twice or three times" in Cairo compared to the 1992 earthquake. The earthquake risk profile reveals that five districts (Al-Sahel, El Basateen, Dar El-Salam, Gharb, and Madinat Nasr sharq) lie in high seismic risks, and three districts (Manshiyat Naser, El-Waily, and Wassat (center)) are in low seismic risk level. Moreover, the building damage estimations reflect that Gharb is the highest vulnerable district. The analysis shows that the Cairo urban area faces high risk. Deteriorating buildings and infrastructure make the city particularly vulnerable to earthquake risks. For instance, more than 90 % of the estimated buildings damages are concentrated within the most densely populated (El Basateen, Dar El-Salam, Gharb, and Madinat Nasr Gharb) districts. Moreover, about 75 % of casualties are in the same districts. Actually, an earthquake risk assessment for Cairo represents a crucial application of the HAZUS earthquake loss estimation model for risk management. Finally, for mitigation, risk reduction, and to improve the seismic performance of structures and assure life safety

Swedish earthquakes and acceleration probabilities

International Nuclear Information System (INIS)

Slunga, R.

1979-03-01

A method to assign probabilities to ground accelerations for Swedish sites is described. As hardly any nearfield instrumental data is available we are left with the problem of interpreting macroseismic data in terms of acceleration. By theoretical wave propagation computations the relation between seismic strength of the earthquake, focal depth, distance and ground accelerations are calculated. We found that most Swedish earthquake of the area, the 1904 earthquake 100 km south of Oslo, is an exception and probably had a focal depth exceeding 25 km. For the nuclear power plant sites an annual probability of 10 -5 has been proposed as interesting. This probability gives ground accelerations in the range 5-20 % for the sites. This acceleration is for a free bedrock site. For consistency all acceleration results in this study are given for bedrock sites. When applicating our model to the 1904 earthquake and assuming the focal zone to be in the lower crust we get the epicentral acceleration of this earthquake to be 5-15 % g. The results above are based on an analyses of macrosismic data as relevant instrumental data is lacking. However, the macroseismic acceleration model deduced in this study gives epicentral ground acceleration of small Swedish earthquakes in agreement with existent distant instrumental data. (author)

Earthquake damage to underground facilities

International Nuclear Information System (INIS)

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

1978-11-01

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

Thermal infrared anomalies of several strong earthquakes.

Science.gov (United States)

Wei, Congxin; Zhang, Yuansheng; Guo, Xiao; Hui, Shaoxing; Qin, Manzhong; Zhang, Ying

2013-01-01

In the history of earthquake thermal infrared research, it is undeniable that before and after strong earthquakes there are significant thermal infrared anomalies which have been interpreted as preseismic precursor in earthquake prediction and forecasting. In this paper, we studied the characteristics of thermal radiation observed before and after the 8 great earthquakes with magnitude up to Ms7.0 by using the satellite infrared remote sensing information. We used new types of data and method to extract the useful anomaly information. Based on the analyses of 8 earthquakes, we got the results as follows. (1) There are significant thermal radiation anomalies before and after earthquakes for all cases. The overall performance of anomalies includes two main stages: expanding first and narrowing later. We easily extracted and identified such seismic anomalies by method of "time-frequency relative power spectrum." (2) There exist evident and different characteristic periods and magnitudes of thermal abnormal radiation for each case. (3) Thermal radiation anomalies are closely related to the geological structure. (4) Thermal radiation has obvious characteristics in abnormal duration, range, and morphology. In summary, we should be sure that earthquake thermal infrared anomalies as useful earthquake precursor can be used in earthquake prediction and forecasting.

Earthquake Warning Performance in Vallejo for the South Napa Earthquake

Science.gov (United States)

Wurman, G.; Price, M.

2014-12-01

In 2002 and 2003, Seismic Warning Systems, Inc. installed first-generation QuakeGuardTM earthquake warning devices at all eight fire stations in Vallejo, CA. These devices are designed to detect the P-wave of an earthquake and initiate predetermined protective actions if the impending shaking is estimated at approximately Modifed Mercalli Intensity V or greater. At the Vallejo fire stations the devices were set up to sound an audio alert over the public address system and to command the equipment bay doors to open. In August 2014, after more than 11 years of operating in the fire stations with no false alarms, the five units that were still in use triggered correctly on the MW 6.0 South Napa earthquake, less than 16 km away. The audio alert sounded in all five stations, providing fire fighters with 1.5 to 2.5 seconds of warning before the arrival of the S-wave, and the equipment bay doors opened in three of the stations. In one station the doors were disconnected from the QuakeGuard device, and another station lost power before the doors opened completely. These problems highlight just a small portion of the complexity associated with realizing actionable earthquake warnings. The issues experienced in this earthquake have already been addressed in subsequent QuakeGuard product generations, with downstream connection monitoring and backup power for critical systems. The fact that the fire fighters in Vallejo were afforded even two seconds of warning at these epicentral distances results from the design of the QuakeGuard devices, which focuses on rapid false positive rejection and ground motion estimates. We discuss the performance of the ground motion estimation algorithms, with an emphasis on the accuracy and timeliness of the estimates at close epicentral distances.

Automatic Earthquake Detection by Active Learning

Science.gov (United States)

Bergen, K.; Beroza, G. C.

2017-12-01

In recent years, advances in machine learning have transformed fields such as image recognition, natural language processing and recommender systems. Many of these performance gains have relied on the availability of large, labeled data sets to train high-accuracy models; labeled data sets are those for which each sample includes a target class label, such as waveforms tagged as either earthquakes or noise. Earthquake seismologists are increasingly leveraging machine learning and data mining techniques to detect and analyze weak earthquake signals in large seismic data sets. One of the challenges in applying machine learning to seismic data sets is the limited labeled data problem; learning algorithms need to be given examples of earthquake waveforms, but the number of known events, taken from earthquake catalogs, may be insufficient to build an accurate detector. Furthermore, earthquake catalogs are known to be incomplete, resulting in training data that may be biased towards larger events and contain inaccurate labels. This challenge is compounded by the class imbalance problem; the events of interest, earthquakes, are infrequent relative to noise in continuous data sets, and many learning algorithms perform poorly on rare classes. In this work, we investigate the use of active learning for automatic earthquake detection. Active learning is a type of semi-supervised machine learning that uses a human-in-the-loop approach to strategically supplement a small initial training set. The learning algorithm incorporates domain expertise through interaction between a human expert and the algorithm, with the algorithm actively posing queries to the user to improve detection performance. We demonstrate the potential of active machine learning to improve earthquake detection performance with limited available training data.

Indoor radon and earthquake

International Nuclear Information System (INIS)

Saghatelyan, E.; Petrosyan, L.; Aghbalyan, Yu.; Baburyan, M.; Araratyan, L.

2004-01-01

For the first time on the basis of the Spitak earthquake of December 1988 (Armenia, December 1988) experience it is found out that the earthquake causes intensive and prolonged radon splashes which, rapidly dispersing in the open space of close-to-earth atmosphere, are contrastingly displayed in covered premises (dwellings, schools, kindergartens) even if they are at considerable distance from the earthquake epicenter, and this multiplies the radiation influence on the population. The interval of splashes includes the period from the first fore-shock to the last after-shock, i.e. several months. The area affected by radiation is larger vs. Armenia's territory. The scale of this impact on population is 12 times higher than the number of people injured in Spitak, Leninakan and other settlements (toll of injured - 25 000 people, radiation-induced diseases in people - over 300 000). The influence of radiation directly correlates with the earthquake force. Such a conclusion is underpinned by indoor radon monitoring data for Yerevan since 1987 (120 km from epicenter) 5450 measurements and multivariate analysis with identification of cause-and-effect linkages between geo dynamics of indoor radon under stable and conditions of Earth crust, behavior of radon in different geological mediums during earthquakes, levels of room radon concentrations and effective equivalent dose of radiation impact of radiation dose on health and statistical data on public health provided by the Ministry of Health. The following hitherto unexplained facts can be considered as consequences of prolonged radiation influence on human organism: long-lasting state of apathy and indifference typical of the population of Armenia during the period of more than a year after the earthquake, prevalence of malignant cancer forms in disaster zones, dominating lung cancer and so on. All urban territories of seismically active regions are exposed to the threat of natural earthquake-provoked radiation influence

Modified-Fibonacci-Dual-Lucas method for earthquake prediction

Science.gov (United States)

Boucouvalas, A. C.; Gkasios, M.; Tselikas, N. T.; Drakatos, G.

2015-06-01

The FDL method makes use of Fibonacci, Dual and Lucas numbers and has shown considerable success in predicting earthquake events locally as well as globally. Predicting the location of the epicenter of an earthquake is one difficult challenge the other being the timing and magnitude. One technique for predicting the onset of earthquakes is the use of cycles, and the discovery of periodicity. Part of this category is the reported FDL method. The basis of the reported FDL method is the creation of FDL future dates based on the onset date of significant earthquakes. The assumption being that each occurred earthquake discontinuity can be thought of as a generating source of FDL time series The connection between past earthquakes and future earthquakes based on FDL numbers has also been reported with sample earthquakes since 1900. Using clustering methods it has been shown that significant earthquakes (conjunct Sun, Moon opposite Sun, Moon conjunct or opposite North or South Modes. In order to test improvement of the method we used all +8R earthquakes recorded since 1900, (86 earthquakes from USGS data). We have developed the FDL numbers for each of those seeds, and examined the earthquake hit rates (for a window of 3, i.e. +-1 day of target date) and for <6.5R. The successes are counted for each one of the 86 earthquake seeds and we compare the MFDL method with the FDL method. In every case we find improvement when the starting seed date is on the planetary trigger date prior to the earthquake. We observe no improvement only when a planetary trigger coincided with the earthquake date and in this case the FDL method coincides with the MFDL. Based on the MDFL method we present the prediction method capable of predicting global events or localized earthquakes and we will discuss the accuracy of the method in as far as the prediction and location parts of the method. We show example calendar style predictions for global events as well as for the Greek region using

Fault geometry and earthquake mechanics

Directory of Open Access Journals (Sweden)

D. J. Andrews

1994-06-01

Full Text Available Earthquake mechanics may be determined by the geometry of a fault system. Slip on a fractal branching fault surface can explain: 1 regeneration of stress irregularities in an earthquake; 2 the concentration of stress drop in an earthquake into asperities; 3 starting and stopping of earthquake slip at fault junctions, and 4 self-similar scaling of earthquakes. Slip at fault junctions provides a natural realization of barrier and asperity models without appealing to variations of fault strength. Fault systems are observed to have a branching fractal structure, and slip may occur at many fault junctions in an earthquake. Consider the mechanics of slip at one fault junction. In order to avoid a stress singularity of order 1/r, an intersection of faults must be a triple junction and the Burgers vectors on the three fault segments at the junction must sum to zero. In other words, to lowest order the deformation consists of rigid block displacement, which ensures that the local stress due to the dislocations is zero. The elastic dislocation solution, however, ignores the fact that the configuration of the blocks changes at the scale of the displacement. A volume change occurs at the junction; either a void opens or intense local deformation is required to avoid material overlap. The volume change is proportional to the product of the slip increment and the total slip since the formation of the junction. Energy absorbed at the junction, equal to confining pressure times the volume change, is not large enongh to prevent slip at a new junction. The ratio of energy absorbed at a new junction to elastic energy released in an earthquake is no larger than P/µ where P is confining pressure and µ is the shear modulus. At a depth of 10 km this dimensionless ratio has th value P/µ= 0.01. As slip accumulates at a fault junction in a number of earthquakes, the fault segments are displaced such that they no longer meet at a single point. For this reason the

Determination of Design Basis Earthquake ground motion

Energy Technology Data Exchange (ETDEWEB)

Kato, Muneaki [Japan Atomic Power Co., Tokyo (Japan)

1997-03-01

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.)

Determination of Design Basis Earthquake ground motion

International Nuclear Information System (INIS)

Kato, Muneaki

1997-01-01

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.)

Impact- and earthquake- proof roof structure

International Nuclear Information System (INIS)

Shohara, Ryoichi.

1990-01-01

Building roofs are constituted with roof slabs, an earthquake proof layer at the upper surface thereof and an impact proof layer made of iron-reinforced concrete disposed further thereover. Since the roofs constitute an earthquake proof structure loading building dampers on the upper surface of the slabs by the concrete layer, seismic inputs of earthquakes to the buildings can be moderated and the impact-proof layer is formed, to ensure the safety to external conditions such as earthquakes or falling accidents of airplane in important facilities such as reactor buildings. (T.M.)

Prompt Assessment of Global Earthquakes for Response (PAGER): A System for Rapidly Determining the Impact of Earthquakes Worldwide

Science.gov (United States)

Earle, Paul S.; Wald, David J.; Jaiswal, Kishor S.; Allen, Trevor I.; Hearne, Michael G.; Marano, Kristin D.; Hotovec, Alicia J.; Fee, Jeremy

2009-01-01

Within minutes of a significant earthquake anywhere on the globe, the U.S. Geological Survey (USGS) Prompt Assessment of Global Earthquakes for Response (PAGER) system assesses its potential societal impact. PAGER automatically estimates the number of people exposed to severe ground shaking and the shaking intensity at affected cities. Accompanying maps of the epicentral region show the population distribution and estimated ground-shaking intensity. A regionally specific comment describes the inferred vulnerability of the regional building inventory and, when available, lists recent nearby earthquakes and their effects. PAGER's results are posted on the USGS Earthquake Program Web site (http://earthquake.usgs.gov/), consolidated in a concise one-page report, and sent in near real-time to emergency responders, government agencies, and the media. Both rapid and accurate results are obtained through manual and automatic updates of PAGER's content in the hours following significant earthquakes. These updates incorporate the most recent estimates of earthquake location, magnitude, faulting geometry, and first-hand accounts of shaking. PAGER relies on a rich set of earthquake analysis and assessment tools operated by the USGS and contributing Advanced National Seismic System (ANSS) regional networks. A focused research effort is underway to extend PAGER's near real-time capabilities beyond population exposure to quantitative estimates of fatalities, injuries, and displaced population.

Application of τc*Pd for identifying damaging earthquakes for earthquake early warning

Science.gov (United States)

Huang, P. L.; Lin, T. L.; Wu, Y. M.

2014-12-01

Earthquake Early Warning System (EEWS) is an effective approach to mitigate earthquake damage. In this study, we used the seismic record by the Kiban Kyoshin network (KiK-net), because it has dense station coverage and co-located borehole strong-motion seismometers along with the free-surface strong-motion seismometers. We used inland earthquakes with moment magnitude (Mw) from 5.0 to 7.3 between 1998 and 2012. We choose 135 events and 10950 strong ground accelerograms recorded by the 696 strong ground accelerographs. Both the free-surface and the borehole data are used to calculate τc and Pd, respectively. The results show that τc*Pd has a good correlation with PGV and is a robust parameter for assessing the potential of damaging earthquake. We propose the value of τc*Pd determined from seconds after the arrival of P wave could be a threshold for the on-site type of EEW.

The Road to Total Earthquake Safety

Science.gov (United States)

Frohlich, Cliff

Cinna Lomnitz is possibly the most distinguished earthquake seismologist in all of Central and South America. Among many other credentials, Lomnitz has personally experienced the shaking and devastation that accompanied no fewer than five major earthquakes—Chile, 1939; Kern County, California, 1952; Chile, 1960; Caracas,Venezuela, 1967; and Mexico City, 1985. Thus he clearly has much to teach someone like myself, who has never even actually felt a real earthquake.What is this slim book? The Road to Total Earthquake Safety summarizes Lomnitz's May 1999 presentation at the Seventh Mallet-Milne Lecture, sponsored by the Society for Earthquake and Civil Engineering Dynamics. His arguments are motivated by the damage that occurred in three earthquakes—Mexico City, 1985; Loma Prieta, California, 1989; and Kobe, Japan, 1995. All three quakes occurred in regions where earthquakes are common. Yet in all three some of the worst damage occurred in structures located a significant distance from the epicenter and engineered specifically to resist earthquakes. Some of the damage also indicated that the structures failed because they had experienced considerable rotational or twisting motion. Clearly, Lomnitz argues, there must be fundamental flaws in the usually accepted models explaining how earthquakes generate strong motions, and how we should design resistant structures.

Earthquake forecasting test for Kanto district to reduce vulnerability of urban mega earthquake disasters

Science.gov (United States)

Yokoi, S.; Tsuruoka, H.; Nanjo, K.; Hirata, N.

2012-12-01

Collaboratory for the Study of Earthquake Predictability (CSEP) is a global project on earthquake predictability research. The final goal of this project is to search for the intrinsic predictability of the earthquake rupture process through forecast testing experiments. The Earthquake Research Institute, the University of Tokyo joined CSEP and started the Japanese testing center called as CSEP-Japan. This testing center provides an open access to researchers contributing earthquake forecast models applied to Japan. Now more than 100 earthquake forecast models were submitted on the prospective experiment. The models are separated into 4 testing classes (1 day, 3 months, 1 year and 3 years) and 3 testing regions covering an area of Japan including sea area, Japanese mainland and Kanto district. We evaluate the performance of the models in the official suite of tests defined by CSEP. The total number of experiments was implemented for approximately 300 rounds. These results provide new knowledge concerning statistical forecasting models. We started a study for constructing a 3-dimensional earthquake forecasting model for Kanto district in Japan based on CSEP experiments under the Special Project for Reducing Vulnerability for Urban Mega Earthquake Disasters. Because seismicity of the area ranges from shallower part to a depth of 80 km due to subducting Philippine Sea plate and Pacific plate, we need to study effect of depth distribution. We will develop models for forecasting based on the results of 2-D modeling. We defined the 3D - forecasting area in the Kanto region with test classes of 1 day, 3 months, 1 year and 3 years, and magnitudes from 4.0 to 9.0 as in CSEP-Japan. In the first step of the study, we will install RI10K model (Nanjo, 2011) and the HISTETAS models (Ogata, 2011) to know if those models have good performance as in the 3 months 2-D CSEP-Japan experiments in the Kanto region before the 2011 Tohoku event (Yokoi et al., in preparation). We use CSEP

Temporal stress changes caused by earthquakes: A review

Science.gov (United States)

Hardebeck, Jeanne L.; Okada, Tomomi

2018-01-01

Earthquakes can change the stress field in the Earth’s lithosphere as they relieve and redistribute stress. Earthquake-induced stress changes have been observed as temporal rotations of the principal stress axes following major earthquakes in a variety of tectonic settings. The stress changes due to the 2011 Mw9.0 Tohoku-Oki, Japan, earthquake were particularly well documented. Earthquake stress rotations can inform our understanding of earthquake physics, most notably addressing the long-standing problem of whether the Earth’s crust at plate boundaries is “strong” or “weak.” Many of the observed stress rotations, including that due to the Tohoku-Oki earthquake, indicate near-complete stress drop in the mainshock. This implies low background differential stress, on the order of earthquake stress drop, supporting the weak crust model. Earthquake stress rotations can also be used to address other important geophysical questions, such as the level of crustal stress heterogeneity and the mechanisms of postseismic stress reloading. The quantitative interpretation of stress rotations is evolving from those based on simple analytical methods to those based on more sophisticated numerical modeling that can capture the spatial-temporal complexity of the earthquake stress changes.

Remote Triggering of the Mw 6.9 Hokkaido Earthquake as a Result of the Mw 6.6 Indonesian Earthquake on September 11, 2008

Directory of Open Access Journals (Sweden)

Cheng-Horng Lin

2012-01-01

Full Text Available Only just recently, the phenomenon of earthquakes being triggered by a distant earthquake has been well established. Yet, most of the triggered earthquakes have been limited to small earthquakes (M < 3. Also, the exact triggering mechanism for earthquakes is still not clear. Here I show how one strong earthquake (Mw = 6.6 is capable of triggering another (Mw = 6.9 at a remote distance (~4750 km. On September 11, 2008, two strong earthquakes with magnitudes (Mw of 6.6 and 6.9 hit respectively in Indonesia and Japan within a short interval of ~21 minutes time. Careful examination of broadband seismograms recorded in Japan shows that the Hokkaido earthquake occurred just as the surface waves generated by the Indonesia earthquake arrived. Although the peak dynamic stress estimated at the focus of the Hokkaido earthquake was just reaching the lower bound for the capability of triggering earthquakes in general, a more plausible mechanism for triggering an earthquake might be attributed to the change of a fault property by fluid infiltration. These observations suggest that the Hokkaido earthquake was likely triggered from a remote distance by the surface waves generated from the Indonesia earthquake. If some more cases can be observed, a temporal warning of possible interaction between strong earthquakes might be concerned in the future.

Living with earthquakes - development and usage of earthquake-resistant construction methods in European and Asian Antiquity

Science.gov (United States)

Kázmér, Miklós; Major, Balázs; Hariyadi, Agus; Pramumijoyo, Subagyo; Ditto Haryana, Yohanes

2010-05-01

Earthquakes are among the most horrible events of nature due to unexpected occurrence, for which no spiritual means are available for protection. The only way of preserving life and property is applying earthquake-resistant construction methods. Ancient Greek architects of public buildings applied steel clamps embedded in lead casing to hold together columns and masonry walls during frequent earthquakes in the Aegean region. Elastic steel provided strength, while plastic lead casing absorbed minor shifts of blocks without fracturing rigid stone. Romans invented concrete and built all sizes of buildings as a single, unflexible unit. Masonry surrounding and decorating concrete core of the wall did not bear load. Concrete resisted minor shaking, yielding only to forces higher than fracture limits. Roman building traditions survived the Dark Ages and 12th century Crusader castles erected in earthquake-prone Syria survive until today in reasonably good condition. Concrete and steel clamping persisted side-by-side in the Roman Empire. Concrete was used for cheap construction as compared to building of masonry. Applying lead-encased steel increased costs, and was avoided whenever possible. Columns of the various forums in Italian Pompeii mostly lack steel fittings despite situated in well-known earthquake-prone area. Whether frequent recurrence of earthquakes in the Naples region was known to inhabitants of Pompeii might be a matter of debate. Seemingly the shock of the AD 62 earthquake was not enough to apply well-known protective engineering methods throughout the reconstruction of the city before the AD 79 volcanic catastrophe. An independent engineering tradition developed on the island of Java (Indonesia). The mortar-less construction technique of 8-9th century Hindu masonry shrines around Yogyakarta would allow scattering of blocks during earthquakes. To prevent dilapidation an intricate mortise-and-tenon system was carved into adjacent faces of blocks. Only the

Bam Earthquake in Iran

CERN Multimedia

2004-01-01

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

Assessment of earthquake-induced landslides hazard in El Salvador after the 2001 earthquakes using macroseismic analysis

Science.gov (United States)

Esposito, Eliana; Violante, Crescenzo; Giunta, Giuseppe; Ángel Hernández, Miguel

2016-04-01

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.

Testing earthquake source inversion methodologies

KAUST Repository

Page, Morgan T.; Mai, Paul Martin; Schorlemmer, Danijel

2011-01-01

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

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

Science.gov (United States)

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

2012-01-01

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

POST Earthquake Debris Management - AN Overview

Science.gov (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

Simulating Earthquakes for Science and Society: Earthquake Visualizations Ideal for use in Science Communication and Education

Science.gov (United States)

de Groot, R.

2008-12-01

The Southern California Earthquake Center (SCEC) has been developing groundbreaking computer modeling capabilities for studying earthquakes. These visualizations were initially shared within the scientific community but have recently gained visibility via television news coverage in Southern California. Computers have opened up a whole new world for scientists working with large data sets, and students can benefit from the same opportunities (Libarkin & Brick, 2002). For example, The Great Southern California ShakeOut was based on a potential magnitude 7.8 earthquake on the southern San Andreas fault. The visualization created for the ShakeOut was a key scientific and communication tool for the earthquake drill. This presentation will also feature SCEC Virtual Display of Objects visualization software developed by SCEC Undergraduate Studies in Earthquake Information Technology interns. According to Gordin and Pea (1995), theoretically visualization should make science accessible, provide means for authentic inquiry, and lay the groundwork to understand and critique scientific issues. This presentation will discuss how the new SCEC visualizations and other earthquake imagery achieve these results, how they fit within the context of major themes and study areas in science communication, and how the efficacy of these tools can be improved.

PRECURSORS OF EARTHQUAKES: VLF SIGNALSIONOSPHERE IONOSPHERE RELATION

Directory of Open Access Journals (Sweden)

Mustafa ULAS

2013-01-01

Full Text Available lot of people have died because of earthquakes every year. Therefore It is crucial to predict the time of the earthquakes reasonable time before it had happed. This paper presents recent information published in the literature about precursors of earthquakes. The relationships between earthquakes and ionosphere are targeted to guide new researches in order to study further to find novel prediction methods.

Building with Earthquakes in Mind

Science.gov (United States)

Mangieri, Nicholas

2016-04-01

Earthquakes are some of the most elusive and destructive disasters humans interact with on this planet. Engineering structures to withstand earthquake shaking is critical to ensure minimal loss of life and property. However, the majority of buildings today in non-traditional earthquake prone areas are not built to withstand this devastating force. Understanding basic earthquake engineering principles and the effect of limited resources helps students grasp the challenge that lies ahead. The solution can be found in retrofitting existing buildings with proper reinforcements and designs to deal with this deadly disaster. The students were challenged in this project to construct a basic structure, using limited resources, that could withstand a simulated tremor through the use of an earthquake shake table. Groups of students had to work together to creatively manage their resources and ideas to design the most feasible and realistic type of building. This activity provided a wealth of opportunities for the students to learn more about a type of disaster they do not experience in this part of the country. Due to the fact that most buildings in New York City were not designed to withstand earthquake shaking, the students were able to gain an appreciation for how difficult it would be to prepare every structure in the city for this type of event.

Meeting the Challenge of Earthquake Risk Globalisation: Towards the Global Earthquake Model GEM (Sergey Soloviev Medal Lecture)

Science.gov (United States)

Zschau, J.

2009-04-01

Earthquake risk, like natural risks in general, has become a highly dynamic and globally interdependent phenomenon. Due to the "urban explosion" in the Third World, an increasingly complex cross linking of critical infrastructure and lifelines in the industrial nations and a growing globalisation of the world's economies, we are presently facing a dramatic increase of our society's vulnerability to earthquakes in practically all seismic regions on our globe. Such fast and global changes cannot be captured with conventional earthquake risk models anymore. The sciences in this field are, therefore, asked to come up with new solutions that are no longer exclusively aiming at the best possible quantification of the present risks but also keep an eye on their changes with time and allow to project these into the future. This does not apply to the vulnerablity component of earthquake risk alone, but also to its hazard component which has been realized to be time-dependent, too. The challenges of earthquake risk dynamics and -globalisation have recently been accepted by the Global Science Forum of the Organisation for Economic Co-operation and Development (OECD - GSF) who initiated the "Global Earthquake Model (GEM)", a public-private partnership for establishing an independent standard to calculate, monitor and communicate earthquake risk globally, raise awareness and promote mitigation.

Possible scenarios for occurrence of M ~ 7 interplate earthquakes prior to and following the 2011 Tohoku-Oki earthquake based on numerical simulation.

Science.gov (United States)

Nakata, Ryoko; Hori, Takane; Hyodo, Mamoru; Ariyoshi, Keisuke

2016-05-10

We show possible scenarios for the occurrence of M ~ 7 interplate earthquakes prior to and following the M ~ 9 earthquake along the Japan Trench, such as the 2011 Tohoku-Oki earthquake. One such M ~ 7 earthquake is so-called the Miyagi-ken-Oki earthquake, for which we conducted numerical simulations of earthquake generation cycles by using realistic three-dimensional (3D) geometry of the subducting Pacific Plate. In a number of scenarios, the time interval between the M ~ 9 earthquake and the subsequent Miyagi-ken-Oki earthquake was equal to or shorter than the average recurrence interval during the later stage of the M ~ 9 earthquake cycle. The scenarios successfully reproduced important characteristics such as the recurrence of M ~ 7 earthquakes, coseismic slip distribution, afterslip distribution, the largest foreshock, and the largest aftershock of the 2011 earthquake. Thus, these results suggest that we should prepare for future M ~ 7 earthquakes in the Miyagi-ken-Oki segment even though this segment recently experienced large coseismic slip in 2011.

Possible scenarios for occurrence of M ~ 7 interplate earthquakes prior to and following the 2011 Tohoku-Oki earthquake based on numerical simulation

Science.gov (United States)

Nakata, Ryoko; Hori, Takane; Hyodo, Mamoru; Ariyoshi, Keisuke

2016-01-01

We show possible scenarios for the occurrence of M ~ 7 interplate earthquakes prior to and following the M ~ 9 earthquake along the Japan Trench, such as the 2011 Tohoku-Oki earthquake. One such M ~ 7 earthquake is so-called the Miyagi-ken-Oki earthquake, for which we conducted numerical simulations of earthquake generation cycles by using realistic three-dimensional (3D) geometry of the subducting Pacific Plate. In a number of scenarios, the time interval between the M ~ 9 earthquake and the subsequent Miyagi-ken-Oki earthquake was equal to or shorter than the average recurrence interval during the later stage of the M ~ 9 earthquake cycle. The scenarios successfully reproduced important characteristics such as the recurrence of M ~ 7 earthquakes, coseismic slip distribution, afterslip distribution, the largest foreshock, and the largest aftershock of the 2011 earthquake. Thus, these results suggest that we should prepare for future M ~ 7 earthquakes in the Miyagi-ken-Oki segment even though this segment recently experienced large coseismic slip in 2011. PMID:27161897

Laboratory generated M -6 earthquakes

Science.gov (United States)

McLaskey, Gregory C.; Kilgore, Brian D.; Lockner, David A.; Beeler, Nicholas M.

2014-01-01

We consider whether mm-scale earthquake-like seismic events generated in laboratory experiments are consistent with our understanding of the physics of larger earthquakes. This work focuses on a population of 48 very small shocks that are foreshocks and aftershocks of stick–slip events occurring on a 2.0 m by 0.4 m simulated strike-slip fault cut through a large granite sample. Unlike the larger stick–slip events that rupture the entirety of the simulated fault, the small foreshocks and aftershocks are contained events whose properties are controlled by the rigidity of the surrounding granite blocks rather than characteristics of the experimental apparatus. The large size of the experimental apparatus, high fidelity sensors, rigorous treatment of wave propagation effects, and in situ system calibration separates this study from traditional acoustic emission analyses and allows these sources to be studied with as much rigor as larger natural earthquakes. The tiny events have short (3–6 μs) rise times and are well modeled by simple double couple focal mechanisms that are consistent with left-lateral slip occurring on a mm-scale patch of the precut fault surface. The repeatability of the experiments indicates that they are the result of frictional processes on the simulated fault surface rather than grain crushing or fracture of fresh rock. Our waveform analysis shows no significant differences (other than size) between the M -7 to M -5.5 earthquakes reported here and larger natural earthquakes. Their source characteristics such as stress drop (1–10 MPa) appear to be entirely consistent with earthquake scaling laws derived for larger earthquakes.

Radon, gas geochemistry, groundwater, and earthquakes

Energy Technology Data Exchange (ETDEWEB)

King, Chi-Yu [Power Reactor and Nuclear Fuel Development Corp., Tono Geoscience Center, Toki, Gifu (Japan)

1998-12-31

Radon monitoring in groundwater, soil air, and atmosphere has been continued in many seismic areas of the world for earthquake-prediction and active-fault studies. Some recent measurements of radon and other geochemical and hydrological parameters have been made for sufficiently long periods, with reliable instruments, and together with measurements of meteorological variables and solid-earth tides. The resultant data are useful in better distinguishing earthquake-related changes from various background noises. Some measurements have been carried out in areas where other geophysical measurements are being made also. Comparative studies of various kinds of geophysical data are helpful in ascertaining the reality of the earthquake-related and fault-related anomalies and in understanding the underlying mechanisms. Spatial anomalies of radon and other terrestrial gasses have been observed for many active faults. Such observations indicate that gas concentrations are very much site dependent, particularly on fault zones where terrestrial fluids may move vertically. Temporal anomalies have been reliably observed before and after some recent earthquakes, including the 1995 Kobe earthquake, and the general pattern of anomaly occurrence remains the same as observed before: They are recorded at only relatively few sensitive sites, which can be at much larger distances than expected from existing earthquake-source models. The sensitivity of a sensitive site is also found to be changeable with time. These results clearly show the inadequacy of the existing dilatancy-fluid diffusion and elastic-dislocation models for earthquake sources to explain earthquake-related geochemical and geophysical changes recorded at large distances. (J.P.N.)

The Christchurch earthquake stroke incidence study.

Science.gov (United States)

Wu, Teddy Y; Cheung, Jeanette; Cole, David; Fink, John N

2014-03-01

We examined the impact of major earthquakes on acute stroke admissions by a retrospective review of stroke admissions in the 6 weeks following the 4 September 2010 and 22 February 2011 earthquakes. The control period was the corresponding 6 weeks in the previous year. In the 6 weeks following the September 2010 earthquake there were 97 acute stroke admissions, with 79 (81.4%) ischaemic infarctions. This was similar to the 2009 control period which had 104 acute stroke admissions, of whom 80 (76.9%) had ischaemic infarction. In the 6 weeks following the February 2011 earthquake, there were 71 stroke admissions, and 61 (79.2%) were ischaemic infarction. This was less than the 96 strokes (72 [75%] ischaemic infarction) in the corresponding control period. None of the comparisons were statistically significant. There was also no difference in the rate of cardioembolic infarction from atrial fibrillation between the study periods. Patients admitted during the February 2011 earthquake period were less likely to be discharged directly home when compared to the control period (31.2% versus 46.9%, p=0.036). There was no observable trend in the number of weekly stroke admissions between the 2 weeks leading to and 6 weeks following the earthquakes. Our results suggest that severe psychological stress from earthquakes did not influence the subsequent short term risk of acute stroke, but the severity of the earthquake in February 2011 and associated civil structural damages may have influenced the pattern of discharge for stroke patients. Copyright © 2013 Elsevier Ltd. All rights reserved.

Source modeling of the 2015 Mw 7.8 Nepal (Gorkha) earthquake sequence: Implications for geodynamics and earthquake hazards

Science.gov (United States)

McNamara, D. E.; Yeck, W. L.; Barnhart, W. D.; Schulte-Pelkum, V.; Bergman, E.; Adhikari, L. B.; Dixit, A.; Hough, S. E.; Benz, H. M.; Earle, P. S.

2017-09-01

The Gorkha earthquake on April 25th, 2015 was a long anticipated, low-angle thrust-faulting event on the shallow décollement between the India and Eurasia plates. We present a detailed multiple-event hypocenter relocation analysis of the Mw 7.8 Gorkha Nepal earthquake sequence, constrained by local seismic stations, and a geodetic rupture model based on InSAR and GPS data. We integrate these observations to place the Gorkha earthquake sequence into a seismotectonic context and evaluate potential earthquake hazard. Major results from this study include (1) a comprehensive catalog of calibrated hypocenters for the Gorkha earthquake sequence; (2) the Gorkha earthquake ruptured a 150 × 60 km patch of the Main Himalayan Thrust (MHT), the décollement defining the plate boundary at depth, over an area surrounding but predominantly north of the capital city of Kathmandu (3) the distribution of aftershock seismicity surrounds the mainshock maximum slip patch; (4) aftershocks occur at or below the mainshock rupture plane with depths generally increasing to the north beneath the higher Himalaya, possibly outlining a 10-15 km thick subduction channel between the overriding Eurasian and subducting Indian plates; (5) the largest Mw 7.3 aftershock and the highest concentration of aftershocks occurred to the southeast the mainshock rupture, on a segment of the MHT décollement that was positively stressed towards failure; (6) the near surface portion of the MHT south of Kathmandu shows no aftershocks or slip during the mainshock. Results from this study characterize the details of the Gorkha earthquake sequence and provide constraints on where earthquake hazard remains high, and thus where future, damaging earthquakes may occur in this densely populated region. Up-dip segments of the MHT should be considered to be high hazard for future damaging earthquakes.

Plant state display device after occurrence of earthquake

International Nuclear Information System (INIS)

Kitada, Yoshio; Yonekura, Kazuyoshi.

1992-01-01

If a nuclear power plant should encounter earthquakes, an earthquake response analysis value previously stored and the earthquakes observed are compared to judge the magnitude of the earthquakes. From the result of the judgement, a possibility that an abnormality is recognized in plant equipment systems after the earthquakes is evaluated, in comparison with a previously stored earthquake fragility data base of each of equipment/systems. The result of the evaluation is displayed in a central control chamber. The plant equipment system is judged such that abnormalities are recognized at a high probability is evaluated by a previously stored earthquake PSA method for the influence of the abnormality on plant safety, and the result is displayed in the central control chamber. (I.S.)

A minimalist model of characteristic earthquakes

DEFF Research Database (Denmark)

Vázquez-Prada, M.; González, Á.; Gómez, J.B.

2002-01-01

In a spirit akin to the sandpile model of self- organized criticality, we present a simple statistical model of the cellular-automaton type which simulates the role of an asperity in the dynamics of a one-dimensional fault. This model produces an earthquake spectrum similar to the characteristic-earthquake...... behaviour of some seismic faults. This model, that has no parameter, is amenable to an algebraic description as a Markov Chain. This possibility illuminates some important results, obtained by Monte Carlo simulations, such as the earthquake size-frequency relation and the recurrence time...... of the characteristic earthquake....

EARTHQUAKE RESEARCH PROBLEMS OF NUCLEAR POWER GENERATORS

Energy Technology Data Exchange (ETDEWEB)

Housner, G. W.; Hudson, D. E.

1963-10-15

Earthquake problems associated with the construction of nuclear power generators require a more extensive and a more precise knowledge of earthquake characteristics and the dynamic behavior of structures than was considered necessary for ordinary buildings. Economic considerations indicate the desirability of additional research on the problems of earthquakes and nuclear reactors. The nature of these earthquake-resistant design problems is discussed and programs of research are recommended. (auth)

Seismic-resistant design of nuclear power stations in Japan, earthquake country. Lessons learned from Chuetsu-oki earthquake

International Nuclear Information System (INIS)

Irikura, Kojiro

2008-01-01

The new assessment (back-check) of earthquake-proof safety was being conducted at Kashiwazaki-Kariwa Nuclear Power Plants, Tokyo Electric Co. in response to a request based on the guideline for reactor evaluation for seismic-resistant design code, revised in 2006, when the 2007 Chuetsu-oki Earthquake occurred and brought about an unexpectedly huge tremor in this area, although the magnitude of the earthquake was only 6.8 but the intensity of earthquake motion exceeded 2.5-fold more than supposed. This paper introduces how and why the guideline for seismic-resistant design of nuclear facilities was revised in 2006, the outline of the Chuetsu-oki Earthquake, and preliminary findings and lessons learned from the Earthquake. The paper specifically discusses on (1) how we may specify in advance geologic active faults as has been overlooked this time, (2) how we can make adequate models for seismic origin from which we can extract its characteristics, and (3) how the estimation of strong ground motion simulation may be possible for ground vibration level of a possibly overlooked fault. (S. Ohno)

Antioptimization of earthquake exitation and response

Directory of Open Access Journals (Sweden)

G. Zuccaro

1998-01-01

Full Text Available The paper presents a novel approach to predict the response of earthquake-excited structures. The earthquake excitation is expanded in terms of series of deterministic functions. The coefficients of the series are represented as a point in N-dimensional space. Each available ccelerogram at a certain site is then represented as a point in the above space, modeling the available fragmentary historical data. The minimum volume ellipsoid, containing all points, is constructed. The ellipsoidal models of uncertainty, pertinent to earthquake excitation, are developed. The maximum response of a structure, subjected to the earthquake excitation, within ellipsoidal modeling of the latter, is determined. This procedure of determining least favorable response was termed in the literature (Elishakoff, 1991 as an antioptimization. It appears that under inherent uncertainty of earthquake excitation, antioptimization analysis is a viable alternative to stochastic approach.

Modified Mercalli intensities for some recent California earthquakes and historic San Francisco Bay Region earthquakes

Science.gov (United States)

Bakun, William H.

1998-01-01

Modified Mercalli Intensity (MMI) data for recent California earthquakes were used by Bakun and Wentworth (1997) to develop a strategy for bounding the location and moment magnitude M of earthquakes from MMI observations only. Bakun (Bull. Seismol. Soc. Amer., submitted) used the Bakun and Wentworth (1997) strategy to analyze 19th century and early 20th century San Francisco Bay Region earthquakes. The MMI data and site corrections used in these studies are listed in this Open-file Report. 

<> earthquakes: a growing contribution to the Catalogue of Strong Italian Earthquakes

Directory of Open Access Journals (Sweden)

E. Guidoboni

2000-06-01

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.

Smartphone MEMS accelerometers and earthquake early warning

Science.gov (United States)

Kong, Q.; Allen, R. M.; Schreier, L.; Kwon, Y. W.

2015-12-01

The low cost MEMS accelerometers in the smartphones are attracting more and more attentions from the science community due to the vast number and potential applications in various areas. We are using the accelerometers inside the smartphones to detect the earthquakes. We did shake table tests to show these accelerometers are also suitable to record large shakings caused by earthquakes. We developed an android app - MyShake, which can even distinguish earthquake movements from daily human activities from the recordings recorded by the accelerometers in personal smartphones and upload trigger information/waveform to our server for further analysis. The data from these smartphones forms a unique datasets for seismological applications, such as earthquake early warning. In this talk I will layout the method we used to recognize earthquake-like movement from single smartphone, and the overview of the whole system that harness the information from a network of smartphones for rapid earthquake detection. This type of system can be easily deployed and scaled up around the global and provides additional insights of the earthquake hazards.

Ionospheric precursors for crustal earthquakes in Italy

Directory of Open Access Journals (Sweden)

L. Perrone

2010-04-01

Full Text Available Crustal earthquakes with magnitude 6.0>M≥5.5 observed in Italy for the period 1979–2009 including the last one at L'Aquila on 6 April 2009 were considered to check if the earlier obtained relationships for ionospheric precursors for strong Japanese earthquakes are valid for the Italian moderate earthquakes. The ionospheric precursors are based on the observed variations of the sporadic E-layer parameters (h'Es, fbEs and foF2 at the ionospheric station Rome. Empirical dependencies for the seismo-ionospheric disturbances relating the earthquake magnitude and the epicenter distance are obtained and they have been shown to be similar to those obtained earlier for Japanese earthquakes. The dependences indicate the process of spreading the disturbance from the epicenter towards periphery during the earthquake preparation process. Large lead times for the precursor occurrence (up to 34 days for M=5.8–5.9 tells about a prolong preparation period. A possibility of using the obtained relationships for the earthquakes prediction is discussed.

Fundamental questions of earthquake statistics, source behavior, and the estimation of earthquake probabilities from possible foreshocks

Science.gov (United States)

Michael, Andrew J.

2012-01-01

Estimates of the probability that an ML 4.8 earthquake, which occurred near the southern end of the San Andreas fault on 24 March 2009, would be followed by an M 7 mainshock over the following three days vary from 0.0009 using a Gutenberg–Richter model of aftershock statistics (Reasenberg and Jones, 1989) to 0.04 using a statistical model of foreshock behavior and long‐term estimates of large earthquake probabilities, including characteristic earthquakes (Agnew and Jones, 1991). I demonstrate that the disparity between the existing approaches depends on whether or not they conform to Gutenberg–Richter behavior. While Gutenberg–Richter behavior is well established over large regions, it could be violated on individual faults if they have characteristic earthquakes or over small areas if the spatial distribution of large‐event nucleations is disproportional to the rate of smaller events. I develop a new form of the aftershock model that includes characteristic behavior and combines the features of both models. This new model and the older foreshock model yield the same results when given the same inputs, but the new model has the advantage of producing probabilities for events of all magnitudes, rather than just for events larger than the initial one. Compared with the aftershock model, the new model has the advantage of taking into account long‐term earthquake probability models. Using consistent parameters, the probability of an M 7 mainshock on the southernmost San Andreas fault is 0.0001 for three days from long‐term models and the clustering probabilities following the ML 4.8 event are 0.00035 for a Gutenberg–Richter distribution and 0.013 for a characteristic‐earthquake magnitude–frequency distribution. Our decisions about the existence of characteristic earthquakes and how large earthquakes nucleate have a first‐order effect on the probabilities obtained from short‐term clustering models for these large events.

The Pocatello Valley, Idaho, earthquake

Science.gov (United States)

Rogers, A. M.; Langer, C.J.; Bucknam, R.C.

1975-01-01

A Richter magnitude 6.3 earthquake occurred at 8:31 p.m mountain daylight time on March 27, 1975, near the Utah-Idaho border in Pocatello Valley. The epicenter of the main shock was located at 42.094° N, 112.478° W, and had a focal depth of 5.5 km. This earthquake was the largest in the continental United States since the destructive San Fernando earthquake of February 1971. The main shock was preceded by a magnitude 4.5 foreshock on March 26. 

Evaluating spatial and temporal relationships between an earthquake cluster near Entiat, central Washington, and the large December 1872 Entiat earthquake

Science.gov (United States)

Brocher, Thomas M.; Blakely, Richard J.; Sherrod, Brian

2017-01-01

We investigate spatial and temporal relations between an ongoing and prolific seismicity cluster in central Washington, near Entiat, and the 14 December 1872 Entiat earthquake, the largest historic crustal earthquake in Washington. A fault scarp produced by the 1872 earthquake lies within the Entiat cluster; the locations and areas of both the cluster and the estimated 1872 rupture surface are comparable. Seismic intensities and the 1–2 m of coseismic displacement suggest a magnitude range between 6.5 and 7.0 for the 1872 earthquake. Aftershock forecast models for (1) the first several hours following the 1872 earthquake, (2) the largest felt earthquakes from 1900 to 1974, and (3) the seismicity within the Entiat cluster from 1976 through 2016 are also consistent with this magnitude range. Based on this aftershock modeling, most of the current seismicity in the Entiat cluster could represent aftershocks of the 1872 earthquake. Other earthquakes, especially those with long recurrence intervals, have long‐lived aftershock sequences, including the Mw">MwMw 7.5 1891 Nobi earthquake in Japan, with aftershocks continuing 100 yrs after the mainshock. Although we do not rule out ongoing tectonic deformation in this region, a long‐lived aftershock sequence can account for these observations.

Prospective testing of Coulomb short-term earthquake forecasts

Science.gov (United States)

Jackson, D. D.; Kagan, Y. Y.; Schorlemmer, D.; Zechar, J. D.; Wang, Q.; Wong, K.

2009-12-01

Earthquake induced Coulomb stresses, whether static or dynamic, suddenly change the probability of future earthquakes. Models to estimate stress and the resulting seismicity changes could help to illuminate earthquake physics and guide appropriate precautionary response. But do these models have improved forecasting power compared to empirical statistical models? The best answer lies in prospective testing in which a fully specified model, with no subsequent parameter adjustments, is evaluated against future earthquakes. The Center of Study of Earthquake Predictability (CSEP) facilitates such prospective testing of earthquake forecasts, including several short term forecasts. Formulating Coulomb stress models for formal testing involves several practical problems, mostly shared with other short-term models. First, earthquake probabilities must be calculated after each “perpetrator” earthquake but before the triggered earthquakes, or “victims”. The time interval between a perpetrator and its victims may be very short, as characterized by the Omori law for aftershocks. CSEP evaluates short term models daily, and allows daily updates of the models. However, lots can happen in a day. An alternative is to test and update models on the occurrence of each earthquake over a certain magnitude. To make such updates rapidly enough and to qualify as prospective, earthquake focal mechanisms, slip distributions, stress patterns, and earthquake probabilities would have to be made by computer without human intervention. This scheme would be more appropriate for evaluating scientific ideas, but it may be less useful for practical applications than daily updates. Second, triggered earthquakes are imperfectly recorded following larger events because their seismic waves are buried in the coda of the earlier event. To solve this problem, testing methods need to allow for “censoring” of early aftershock data, and a quantitative model for detection threshold as a function of

Surface latent heat flux as an earthquake precursor

Directory of Open Access Journals (Sweden)

S. Dey

2003-01-01

Full Text Available The analysis of surface latent heat flux (SLHF from the epicentral regions of five recent earthquakes that occurred in close proximity to the oceans has been found to show anomalous behavior. The maximum increase of SLHF is found 2–7 days prior to the main earthquake event. This increase is likely due to an ocean-land-atmosphere interaction. The increase of SLHF prior to the main earthquake event is attributed to the increase in infrared thermal (IR temperature in the epicentral and surrounding region. The anomalous increase in SLHF shows great potential in providing early warning of a disastrous earthquake, provided that there is a better understanding of the background noise due to the tides and monsoon in surface latent heat flux. Efforts have been made to understand the level of background noise in the epicentral regions of the five earthquakes considered in the present paper. A comparison of SLHF from the epicentral regions over the coastal earthquakes and the earthquakes that occurred far away from the coast has been made and it has been found that the anomalous behavior of SLHF prior to the main earthquake event is only associated with the coastal earthquakes.

Method to Determine Appropriate Source Models of Large Earthquakes Including Tsunami Earthquakes for Tsunami Early Warning in Central America

Science.gov (United States)

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

2017-08-01

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.

Earthquake simulation, actual earthquake monitoring and analytical methods for soil-structure interaction investigation

Energy Technology Data Exchange (ETDEWEB)

Tang, H T [Seismic Center, Electric Power Research Institute, Palo Alto, CA (United States)

1988-07-01

Approaches for conducting in-situ soil-structure interaction experiments are discussed. High explosives detonated under the ground can generate strong ground motion to induce soil-structure interaction (SSI). The explosive induced data are useful in studying the dynamic characteristics of the soil-structure system associated with the inertial aspect of the SSI problem. The plane waves generated by the explosives cannot adequately address the kinematic interaction associated with actual earthquakes because of he difference in wave fields and their effects. Earthquake monitoring is ideal for obtaining SSI data that can address all aspects of the SSI problem. The only limitation is the level of excitation that can be obtained. Neither the simulated earthquake experiments nor the earthquake monitoring experiments can have exact similitude if reduced scale test structures are used. If gravity effects are small, reasonable correlations between the scaled model and the prototype can be obtained provided that input motion can be scaled appropriately. The key product of the in-situ experiments is the data base that can be used to qualify analytical methods for prototypical applications. (author)

Real-time earthquake data feasible

Science.gov (United States)

Bush, Susan

Scientists agree that early warning devices and monitoring of both Hurricane Hugo and the Mt. Pinatubo volcanic eruption saved thousands of lives. What would it take to develop this sort of early warning and monitoring system for earthquake activity?Not all that much, claims a panel assigned to study the feasibility, costs, and technology needed to establish a real-time earthquake monitoring (RTEM) system. The panel, drafted by the National Academy of Science's Committee on Seismology, has presented its findings in Real-Time Earthquake Monitoring. The recently released report states that “present technology is entirely capable of recording and processing data so as to provide real-time information, enabling people to mitigate somewhat the earthquake disaster.” RTEM systems would consist of two parts—an early warning system that would give a few seconds warning before severe shaking, and immediate postquake information within minutes of the quake that would give actual measurements of the magnitude. At this time, however, this type of warning system has not been addressed at the national level for the United States and is not included in the National Earthquake Hazard Reduction Program, according to the report.

Critical behavior in earthquake energy dissipation

Science.gov (United States)

Wanliss, James; Muñoz, Víctor; Pastén, Denisse; Toledo, Benjamín; Valdivia, Juan Alejandro

2017-09-01

We explore bursty multiscale energy dissipation from earthquakes flanked by latitudes 29° S and 35.5° S, and longitudes 69.501° W and 73.944° W (in the Chilean central zone). Our work compares the predictions of a theory of nonequilibrium phase transitions with nonstandard statistical signatures of earthquake complex scaling behaviors. For temporal scales less than 84 hours, time development of earthquake radiated energy activity follows an algebraic arrangement consistent with estimates from the theory of nonequilibrium phase transitions. There are no characteristic scales for probability distributions of sizes and lifetimes of the activity bursts in the scaling region. The power-law exponents describing the probability distributions suggest that the main energy dissipation takes place due to largest bursts of activity, such as major earthquakes, as opposed to smaller activations which contribute less significantly though they have greater relative occurrence. The results obtained provide statistical evidence that earthquake energy dissipation mechanisms are essentially "scale-free", displaying statistical and dynamical self-similarity. Our results provide some evidence that earthquake radiated energy and directed percolation belong to a similar universality class.

Centrality in earthquake multiplex networks

Science.gov (United States)

Lotfi, Nastaran; Darooneh, Amir Hossein; Rodrigues, Francisco A.

2018-06-01

Seismic time series has been mapped as a complex network, where a geographical region is divided into square cells that represent the nodes and connections are defined according to the sequence of earthquakes. In this paper, we map a seismic time series to a temporal network, described by a multiplex network, and characterize the evolution of the network structure in terms of the eigenvector centrality measure. We generalize previous works that considered the single layer representation of earthquake networks. Our results suggest that the multiplex representation captures better earthquake activity than methods based on single layer networks. We also verify that the regions with highest seismological activities in Iran and California can be identified from the network centrality analysis. The temporal modeling of seismic data provided here may open new possibilities for a better comprehension of the physics of earthquakes.

Parallelization of the Coupled Earthquake Model

Science.gov (United States)

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

2007-01-01

This Web-based tsunami simulation system allows users to remotely run a model on JPL s supercomputers for a given undersea earthquake. At the time of this reporting, predicting tsunamis on the Internet has never happened before. This new code directly couples the earthquake model and the ocean model on parallel computers and improves simulation speed. Seismometers can only detect information from earthquakes; they cannot detect whether or not a tsunami may occur as a result of the earthquake. When earthquake-tsunami models are coupled with the improved computational speed of modern, high-performance computers and constrained by remotely sensed data, they are able to provide early warnings for those coastal regions at risk. The software is capable of testing NASA s satellite observations of tsunamis. It has been successfully tested for several historical tsunamis, has passed all alpha and beta testing, and is well documented for users.

Ionospheric Anomaly before Kyushu|Japan Earthquake

Directory of Open Access Journals (Sweden)

YANG Li

2017-05-01

Full Text Available GIM data released by IGS is used in the article and a new method of combining the Sliding Time Window Method and the Ionospheric TEC correlation analysis method of adjacent grid points is proposed to study the relationship between pre-earthquake ionospheric anomalies and earthquake. By analyzing the abnormal change of TEC in the 5 grid points around the seismic region, the abnormal change of ionospheric TEC is found before the earthquake and the correlation between the TEC sequences of lattice points is significantly affected by earthquake. Based on the analysis of the spatial distribution of TEC anomaly, anomalies of 6 h, 12 h and 6 h were found near the epicenter three days before the earthquake. Finally, ionospheric tomographic technology is used to do tomographic inversion on electron density. And the distribution of the electron density in the ionospheric anomaly is further analyzed.

Retrospective analysis of the Spitak earthquake

Directory of Open Access Journals (Sweden)

A. K. Tovmassian

1995-06-01

Full Text Available Based on the retrospective analysis of numerous data and studies of the Spitak earthquake the present work at- tempts to shed light on different aspects of that catastrophic seismic event which occurred in Northern Arme- nia on December 7, 1988. The authors follow a chronological order of presentation, namely: changes in geo- sphere, atmosphere, biosphere during the preparation of the Spitak earthquake, foreshocks, main shock, after- shocks, focal mechanisms, historical seismicity; seismotectonic position of the source, strong motion records, site effects; the macroseismic effect, collapse of buildings and structures; rescue activities; earthquake conse- quences; and the lessons of the Spitak earthquake.

Nonlinear acoustic/seismic waves in earthquake processes

International Nuclear Information System (INIS)

Johnson, Paul A.

2012-01-01

Nonlinear dynamics induced by seismic sources and seismic waves are common in Earth. Observations range from seismic strong ground motion (the most damaging aspect of earthquakes), intense near-source effects, and distant nonlinear effects from the source that have important consequences. The distant effects include dynamic earthquake triggering—one of the most fascinating topics in seismology today—which may be elastically nonlinearly driven. Dynamic earthquake triggering is the phenomenon whereby seismic waves generated from one earthquake trigger slip events on a nearby or distant fault. Dynamic triggering may take place at distances thousands of kilometers from the triggering earthquake, and includes triggering of the entire spectrum of slip behaviors currently identified. These include triggered earthquakes and triggered slow, silent-slip during which little seismic energy is radiated. It appears that the elasticity of the fault gouge—the granular material located between the fault blocks—is key to the triggering phenomenon.

On the plant operators performance during earthquake

International Nuclear Information System (INIS)

Kitada, Y.; Yoshimura, S.; Abe, M.; Niwa, H.; Yoneda, T.; Matsunaga, M.; Suzuki, T.

1994-01-01

There is little data on which to judge the performance of plant operators during and after strong earthquakes. In order to obtain such data to enhance the reliability on the plant operation, a Japanese utility and a power plant manufacturer carried out a vibration test using a shaking table. The purpose of the test was to investigate operator performance, i.e., the quickness and correctness in switch handling and panel meter read-out. The movement of chairs during earthquake as also of interest, because if the chairs moved significantly or turned over during a strong earthquake, some arresting mechanism would be required for the chair. Although there were differences between the simulated earthquake motions used and actual earthquakes mainly due to the specifications of the shaking table, the earthquake motions had almost no influence on the operators of their capability (performance) for operating the simulated console and the personal computers

Data base pertinent to earthquake design basis

International Nuclear Information System (INIS)

Sharma, R.D.

1988-01-01

Mitigation of earthquake risk from impending strong earthquakes is possible provided the hazard can be assessed, and translated into appropriate design inputs. This requires defining the seismic risk problem, isolating the risk factors and quantifying risk in terms of physical parameters, which are suitable for application in design. Like all other geological phenomena, past earthquakes hold the key to the understanding of future ones. Quantificatio n of seismic risk at a site calls for investigating the earthquake aspects of the site region and building a data base. The scope of such investigations is il lustrated in Figure 1 and 2. A more detailed definition of the earthquake problem in engineering design is given elsewhere (Sharma, 1987). The present document discusses the earthquake data base, which is required to support a seismic risk evaluation programme in the context of the existing state of the art. (author). 8 tables, 10 figs., 54 refs

Seismic-electromagnetic precursors of Romania's Vrancea earthquakes

International Nuclear Information System (INIS)

Enescu, B.D.; Enescu, C.; Constantin, A. P.

1999-01-01

Diagrams were plotted from electromagnetic data that were recorded at Muntele Rosu Observatory during December 1996 to January 1997, and December 1997 to September 1998. The times when Vrancea earthquakes of magnitudes M ≥ 3.9 occurred within these periods are marked on the diagrams.The parameters of the earthquakes are given in a table which also includes information on the magnetic and electric anomalies (perturbations) preceding these earthquakes. The magnetic data prove that Vrancea earthquakes are preceded by magnetic perturbations that may be regarded as their short-term precursors. Perturbations, which could likewise be seen as short-term precursors of Vrancea earthquakes, are also noticed in the electric records. Still, a number of electric data do cast a doubt on their forerunning nature. Some suggestions are made in the end of the paper on how electromagnetic research should go ahead to be of use for Vrancea earthquake prediction. (authors)

Earthquake activity along the Himalayan orogenic belt

Science.gov (United States)

Bai, L.; Mori, J. J.

2017-12-01

The collision between the Indian and Eurasian plates formed the Himalayas, the largest orogenic belt on the Earth. The entire region accommodates shallow earthquakes, while intermediate-depth earthquakes are concentrated at the eastern and western Himalayan syntaxis. Here we investigate the focal depths, fault plane solutions, and source rupture process for three earthquake sequences, which are located at the western, central and eastern regions of the Himalayan orogenic belt. The Pamir-Hindu Kush region is located at the western Himalayan syntaxis and is characterized by extreme shortening of the upper crust and strong interaction of various layers of the lithosphere. Many shallow earthquakes occur on the Main Pamir Thrust at focal depths shallower than 20 km, while intermediate-deep earthquakes are mostly located below 75 km. Large intermediate-depth earthquakes occur frequently at the western Himalayan syntaxis about every 10 years on average. The 2015 Nepal earthquake is located in the central Himalayas. It is a typical megathrust earthquake that occurred on the shallow portion of the Main Himalayan Thrust (MHT). Many of the aftershocks are located above the MHT and illuminate faulting structures in the hanging wall with dip angles that are steeper than the MHT. These observations provide new constraints on the collision and uplift processes for the Himalaya orogenic belt. The Indo-Burma region is located south of the eastern Himalayan syntaxis, where the strike of the plate boundary suddenly changes from nearly east-west at the Himalayas to nearly north-south at the Burma Arc. The Burma arc subduction zone is a typical oblique plate convergence zone. The eastern boundary is the north-south striking dextral Sagaing fault, which hosts many shallow earthquakes with focal depth less than 25 km. In contrast, intermediate-depth earthquakes along the subduction zone reflect east-west trending reverse faulting.

Prediction of site specific ground motion for large earthquake

International Nuclear Information System (INIS)

Kamae, Katsuhiro; Irikura, Kojiro; Fukuchi, Yasunaga.

1990-01-01

In this paper, we apply the semi-empirical synthesis method by IRIKURA (1983, 1986) to the estimation of site specific ground motion using accelerograms observed at Kumatori in Osaka prefecture. Target earthquakes used here are a comparatively distant earthquake (Δ=95 km, M=5.6) caused by the YAMASAKI fault and a near earthquake (Δ=27 km, M=5.6). The results obtained are as follows. 1) The accelerograms from the distant earthquake (M=5.6) are synthesized using the aftershock records (M=4.3) for 1983 YAMASAKI fault earthquake whose source parameters have been obtained by other authors from the hypocentral distribution of the aftershocks. The resultant synthetic motions show a good agreement with the observed ones. 2) The synthesis for a near earthquake (M=5.6, we call this target earthquake) are made using a small earthquake which occurred in the neighborhood of the target earthquake. Here, we apply two methods for giving the parameters for synthesis. One method is to use the parameters of YAMASAKI fault earthquake which has the same magnitude as the target earthquake, and the other is to use the parameters obtained from several existing empirical formulas. The resultant synthetic motion with the former parameters shows a good agreement with the observed one, but that with the latter does not. 3) We estimate the source parameters from the source spectra of several earthquakes which have been observed in this site. Consequently we find that the small earthquakes (M<4) as Green's functions should be carefully used because the stress drops are not constant. 4) We propose that we should designate not only the magnitudes but also seismic moments of the target earthquake and the small earthquake. (J.P.N.)

Clustered and transient earthquake sequences in mid-continents

Science.gov (United States)

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

2012-12-01

Earthquakes result from sudden release of strain energy on faults. On plate boundary faults, strain energy is constantly accumulating from steady and relatively rapid relative plate motion, so large earthquakes continue to occur so long as motion continues on the boundary. In contrast, such steady accumulation of stain energy does not occur on faults in mid-continents, because the far-field tectonic loading is not steadily distributed between faults, and because stress perturbations from complex fault interactions and other stress triggers can be significant relative to the slow tectonic stressing. Consequently, mid-continental earthquakes are often temporally clustered and transient, and spatially migrating. This behavior is well illustrated by large earthquakes in North China in the past two millennia, during which no single large earthquakes repeated on the same fault segments, but moment release between large fault systems was complementary. Slow tectonic loading in mid-continents also causes long aftershock sequences. We show that the recent small earthquakes in the Tangshan region of North China are aftershocks of the 1976 Tangshan earthquake (M 7.5), rather than indicators of a new phase of seismic activity in North China, as many fear. Understanding the transient behavior of mid-continental earthquakes has important implications for assessing earthquake hazards. The sequence of large earthquakes in the New Madrid Seismic Zone (NMSZ) in central US, which includes a cluster of M~7 events in 1811-1812 and perhaps a few similar ones in the past millennium, is likely a transient process, releasing previously accumulated elastic strain on recently activated faults. If so, this earthquake sequence will eventually end. Using simple analysis and numerical modeling, we show that the large NMSZ earthquakes may be ending now or in the near future.

Investigating landslides caused by earthquakes - A historical review

Science.gov (United States)

Keefer, D.K.

2002-01-01

Post-earthquake field investigations of landslide occurrence have provided a basis for understanding, evaluating, and mapping the hazard and risk associated with earthquake-induced landslides. This paper traces the historical development of knowledge derived from these investigations. Before 1783, historical accounts of the occurrence of landslides in earthquake are typically so incomplete and vague that conclusions based on these accounts are of limited usefulness. For example, the number of landslides triggered by a given event is almost always greatly underestimated. The first formal, scientific post-earthquake investigation that included systematic documentation of the landslides was undertaken in the Calabria region of Italy after the 1783 earthquake swarm. From then until the mid-twentieth century, the best information on earthquake-induced landslides came from a succession of post-earthquake investigations largely carried out by formal commissions that undertook extensive ground-based field studies. Beginning in the mid-twentieth century, when the use of aerial photography became widespread, comprehensive inventories of landslide occurrence have been made for several earthquakes in the United States, Peru, Guatemala, Italy, El Salvador, Japan, and Taiwan. Techniques have also been developed for performing "retrospective" analyses years or decades after an earthquake that attempt to reconstruct the distribution of landslides triggered by the event. The additional use of Geographic Information System (GIS) processing and digital mapping since about 1989 has greatly facilitated the level of analysis that can applied to mapped distributions of landslides. Beginning in 1984, synthesis of worldwide and national data on earthquake-induced landslides have defined their general characteristics and relations between their occurrence and various geologic and seismic parameters. However, the number of comprehensive post-earthquake studies of landslides is still

Post-Earthquake Reconstruction — in Context of Housing

Science.gov (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?

Measures for groundwater security during and after the Hanshin-Awaji earthquake (1995) and the Great East Japan earthquake (2011), Japan

Science.gov (United States)

Tanaka, Tadashi

2016-03-01

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.

New geological perspectives on earthquake recurrence models

International Nuclear Information System (INIS)

Schwartz, D.P.

1997-01-01

In most areas of the world the record of historical seismicity is too short or uncertain to accurately characterize the future distribution of earthquakes of different sizes in time and space. Most faults have not ruptured once, let alone repeatedly. Ultimately, the ability to correctly forecast the magnitude, location, and probability of future earthquakes depends on how well one can quantify the past behavior of earthquake sources. Paleoseismological trenching of active faults, historical surface ruptures, liquefaction features, and shaking-induced ground deformation structures provides fundamental information on the past behavior of earthquake sources. These studies quantify (a) the timing of individual past earthquakes and fault slip rates, which lead to estimates of recurrence intervals and the development of recurrence models and (b) the amount of displacement during individual events, which allows estimates of the sizes of past earthquakes on a fault. When timing and slip per event are combined with information on fault zone geometry and structure, models that define individual rupture segments can be developed. Paleoseismicity data, in the form of timing and size of past events, provide a window into the driving mechanism of the earthquake engine--the cycle of stress build-up and release

Earthquake Education in Prime Time

Science.gov (United States)

de Groot, R.; Abbott, P.; Benthien, M.

2004-12-01

Since 2001, the Southern California Earthquake Center (SCEC) has collaborated on several video production projects that feature important topics related to earthquake science, engineering, and preparedness. These projects have also fostered many fruitful and sustained partnerships with a variety of organizations that have a stake in hazard education and preparedness. The Seismic Sleuths educational video first appeared in the spring season 2001 on Discovery Channel's Assignment Discovery. Seismic Sleuths is based on a highly successful curriculum package developed jointly by the American Geophysical Union and The Department of Homeland Security Federal Emergency Management Agency. The California Earthquake Authority (CEA) and the Institute for Business and Home Safety supported the video project. Summer Productions, a company with a reputation for quality science programming, produced the Seismic Sleuths program in close partnership with scientists, engineers, and preparedness experts. The program has aired on the National Geographic Channel as recently as Fall 2004. Currently, SCEC is collaborating with Pat Abbott, a geology professor at San Diego State University (SDSU) on the video project Written In Stone: Earthquake Country - Los Angeles. Partners on this project include the California Seismic Safety Commission, SDSU, SCEC, CEA, and the Insurance Information Network of California. This video incorporates live-action demonstrations, vivid animations, and a compelling host (Abbott) to tell the story about earthquakes in the Los Angeles region. The Written in Stone team has also developed a comprehensive educator package that includes the video, maps, lesson plans, and other supporting materials. We will present the process that facilitates the creation of visually effective, factually accurate, and entertaining video programs. We acknowledge the need to have a broad understanding of the literature related to communication, media studies, science education, and

Defeating Earthquakes

Science.gov (United States)

Stein, R. S.

2012-12-01

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

Earthquakes of Garhwal Himalaya region of NW Himalaya, India: A study of relocated earthquakes and their seismogenic source and stress

Science.gov (United States)

R, A. P.; Paul, A.; Singh, S.

2017-12-01

Since the continent-continent collision 55 Ma, the Himalaya has accommodated 2000 km of convergence along its arc. The strain energy is being accumulated at a rate of 37-44 mm/yr and releases at time as earthquakes. The Garhwal Himalaya is located at the western side of a Seismic Gap, where a great earthquake is overdue atleast since 200 years. This seismic gap (Central Seismic Gap: CSG) with 52% probability for a future great earthquake is located between the rupture zones of two significant/great earthquakes, viz. the 1905 Kangra earthquake of M 7.8 and the 1934 Bihar-Nepal earthquake of M 8.0; and the most recent one, the 2015 Gorkha earthquake of M 7.8 is in the eastern side of this seismic gap (CSG). The Garhwal Himalaya is one of the ideal locations of the Himalaya where all the major Himalayan structures and the Himalayan Seimsicity Belt (HSB) can ably be described and studied. In the present study, we are presenting the spatio-temporal analysis of the relocated local micro-moderate earthquakes, recorded by a seismicity monitoring network, which is operational since, 2007. The earthquake locations are relocated using the HypoDD (double difference hypocenter method for earthquake relocations) program. The dataset from July, 2007- September, 2015 have been used in this study to estimate their spatio-temporal relationships, moment tensor (MT) solutions for the earthquakes of M>3.0, stress tensors and their interactions. We have also used the composite focal mechanism solutions for small earthquakes. The majority of the MT solutions show thrust type mechanism and located near the mid-crustal-ramp (MCR) structure of the detachment surface at 8-15 km depth beneath the outer lesser Himalaya and higher Himalaya regions. The prevailing stress has been identified to be compressional towards NNE-SSW, which is the direction of relative plate motion between the India and Eurasia continental plates. The low friction coefficient estimated along with the stress inversions

Mexican Earthquakes and Tsunamis Catalog Reviewed

Science.gov (United States)

Ramirez-Herrera, M. T.; Castillo-Aja, R.

2015-12-01

Today the availability of information on the internet makes online catalogs very easy to access by both scholars and the public in general. The catalog in the "Significant Earthquake Database", managed by the National Center for Environmental Information (NCEI formerly NCDC), NOAA, allows access by deploying tabular and cartographic data related to earthquakes and tsunamis contained in the database. The NCEI catalog is the product of compiling previously existing catalogs, historical sources, newspapers, and scientific articles. Because NCEI catalog has a global coverage the information is not homogeneous. Existence of historical information depends on the presence of people in places where the disaster occurred, and that the permanence of the description is preserved in documents and oral tradition. In the case of instrumental data, their availability depends on the distribution and quality of seismic stations. Therefore, the availability of information for the first half of 20th century can be improved by careful analysis of the available information and by searching and resolving inconsistencies. This study shows the advances we made in upgrading and refining data for the earthquake and tsunami catalog of Mexico since 1500 CE until today, presented in the format of table and map. Data analysis allowed us to identify the following sources of error in the location of the epicenters in existing catalogs: • Incorrect coordinate entry • Place name erroneous or mistaken • Too general data that makes difficult to locate the epicenter, mainly for older earthquakes • Inconsistency of earthquakes and the tsunami occurrence: earthquake's epicenter located too far inland reported as tsunamigenic. The process of completing the catalogs directly depends on the availability of information; as new archives are opened for inspection, there are more opportunities to complete the history of large earthquakes and tsunamis in Mexico. Here, we also present new earthquake and

Earthquake risk assessment of Alexandria, Egypt

Science.gov (United States)

Badawy, Ahmed; Gaber, Hanan; Ibrahim, Hamza

2015-01-01

Throughout historical and recent times, Alexandria has suffered great damage due to earthquakes from both near- and far-field sources. Sometimes, the sources of such damages are not well known. During the twentieth century, the city was shaken by several earthquakes generated from inland dislocations (e.g., 29 Apr. 1974, 12 Oct. 1992, and 28 Dec. 1999) and the African continental margin (e.g., 12 Sept. 1955 and 28 May 1998). Therefore, this study estimates the earthquake ground shaking and the consequent impacts in Alexandria on the basis of two earthquake scenarios. The simulation results show that Alexandria affected by both earthquakes scenarios relatively in the same manner despite the number of casualties during the first scenario (inland dislocation) is twice larger than the second one (African continental margin). An expected percentage of 2.27 from Alexandria's total constructions (12.9 millions, 2006 Census) will be affected, 0.19 % injuries and 0.01 % deaths of the total population (4.1 millions, 2006 Census) estimated by running the first scenario. The earthquake risk profile reveals that three districts (Al-Montazah, Al-Amriya, and Shark) lie in high seismic risks, two districts (Gharb and Wasat) are in moderate, and two districts (Al-Gomrok and Burg El-Arab) are in low seismic risk level. Moreover, the building damage estimations reflect that Al-Montazah is the highest vulnerable district whereas 73 % of expected damages were reported there. The undertaken analysis shows that the Alexandria urban area faces high risk. Informal areas and deteriorating buildings and infrastructure make the city particularly vulnerable to earthquake risks. For instance, more than 90 % of the estimated earthquake risks (buildings damages) are concentrated at the most densely populated (Al-Montazah, Al-Amriya, and Shark) districts. Moreover, about 75 % of casualties are in the same districts.

Towards the Future "Earthquake" School in the Cloud: Near-real Time Earthquake Games Competition in Taiwan

Science.gov (United States)

Chen, K. H.; Liang, W. T.; Wu, Y. F.; Yen, E.

2014-12-01

To prevent the future threats of natural disaster, it is important to understand how the disaster happened, why lives were lost, and what lessons have been learned. By that, the attitude of society toward natural disaster can be transformed from training to learning. The citizen-seismologists-in-Taiwan project is designed to elevate the quality of earthquake science education by means of incorporating earthquake/tsunami stories and near-real time earthquake games competition into the traditional curricula in schools. Through pilot of courses and professional development workshops, we have worked closely with teachers from elementary, junior high, and senior high schools, to design workable teaching plans through a practical operation of seismic monitoring at home or school. We will introduce how the 9-years-old do P- and S-wave picking and measure seismic intensity through interactive learning platform, how do scientists and school teachers work together, and how do we create an environment to facilitate continuous learning (i.e., near-real time earthquake games competition), to make earthquake science fun.

Rapid earthquake characterization using MEMS accelerometers and volunteer hosts following the M 7.2 Darfield, New Zealand, Earthquake

Science.gov (United States)

Lawrence, J. F.; Cochran, E.S.; Chung, A.; Kaiser, A.; Christensen, C. M.; Allen, R.; Baker, J.W.; Fry, B.; Heaton, T.; Kilb, Debi; Kohler, M.D.; Taufer, M.

2014-01-01

We test the feasibility of rapidly detecting and characterizing earthquakes with the Quake‐Catcher Network (QCN) that connects low‐cost microelectromechanical systems accelerometers to a network of volunteer‐owned, Internet‐connected computers. Following the 3 September 2010 M 7.2 Darfield, New Zealand, earthquake we installed over 180 QCN sensors in the Christchurch region to record the aftershock sequence. The sensors are monitored continuously by the host computer and send trigger reports to the central server. The central server correlates incoming triggers to detect when an earthquake has occurred. The location and magnitude are then rapidly estimated from a minimal set of received ground‐motion parameters. Full seismic time series are typically not retrieved for tens of minutes or even hours after an event. We benchmark the QCN real‐time detection performance against the GNS Science GeoNet earthquake catalog. Under normal network operations, QCN detects and characterizes earthquakes within 9.1 s of the earthquake rupture and determines the magnitude within 1 magnitude unit of that reported in the GNS catalog for 90% of the detections.

Earthquake likelihood model testing

Science.gov (United States)

Schorlemmer, D.; Gerstenberger, M.C.; Wiemer, S.; Jackson, D.D.; Rhoades, D.A.

2007-01-01

INTRODUCTIONThe Regional Earthquake Likelihood Models (RELM) project aims to produce and evaluate alternate models of earthquake potential (probability per unit volume, magnitude, and time) for California. Based on differing assumptions, these models are produced to test the validity of their assumptions and to explore which models should be incorporated in seismic hazard and risk evaluation. Tests based on physical and geological criteria are useful but we focus on statistical methods using future earthquake catalog data only. We envision two evaluations: a test of consistency with observed data and a comparison of all pairs of models for relative consistency. Both tests are based on the likelihood method, and both are fully prospective (i.e., the models are not adjusted to fit the test data). To be tested, each model must assign a probability to any possible event within a specified region of space, time, and magnitude. For our tests the models must use a common format: earthquake rates in specified “bins” with location, magnitude, time, and focal mechanism limits.Seismology cannot yet deterministically predict individual earthquakes; however, it should seek the best possible models for forecasting earthquake occurrence. This paper describes the statistical rules of an experiment to examine and test earthquake forecasts. The primary purposes of the tests described below are to evaluate physical models for earthquakes, assure that source models used in seismic hazard and risk studies are consistent with earthquake data, and provide quantitative measures by which models can be assigned weights in a consensus model or be judged as suitable for particular regions.In this paper we develop a statistical method for testing earthquake likelihood models. A companion paper (Schorlemmer and Gerstenberger 2007, this issue) discusses the actual implementation of these tests in the framework of the RELM initiative.Statistical testing of hypotheses is a common task and a

The use of radon as an earthquake precursor

International Nuclear Information System (INIS)

Ramola, R.C.; Singh, M.; Sandhu, A.S.; Singh, S.; Virk, H.S.

1990-01-01

Radon monitoring for earthquake prediction is part of an integral approach since the discovery of coherent and time anomalous radon concentrations prior to, during and after the 1966 Tashkent earthquake. In this paper some studies of groundwater and soil gas radon content in relation to earthquake activities are reviewed. Laboratory experiments and the development of groundwater and soil gas radon monitoring systems are described. In addition, radon monitoring studies conducted at the Guru Nanak Dev University Campus since 1986 are presented in detail. During these studies some anomalous changes in radon concentration were recorded before earthquakes occurred in the region. The anomalous radon increases are independent of meteorological conditions and appear to be caused by strain changes, which precede the earthquake. Anomalous changes in radon concentration before an earthquake suggest that radon monitoring can serve as an additional technique in the earthquake prediction programme in India. (author)

Modeling fast and slow earthquakes at various scales.

Science.gov (United States)

Ide, Satoshi

2014-01-01

Earthquake sources represent dynamic rupture within rocky materials at depth and often can be modeled as propagating shear slip controlled by friction laws. These laws provide boundary conditions on fault planes embedded in elastic media. Recent developments in observation networks, laboratory experiments, and methods of data analysis have expanded our knowledge of the physics of earthquakes. Newly discovered slow earthquakes are qualitatively different phenomena from ordinary fast earthquakes and provide independent information on slow deformation at depth. Many numerical simulations have been carried out to model both fast and slow earthquakes, but problems remain, especially with scaling laws. Some mechanisms are required to explain the power-law nature of earthquake rupture and the lack of characteristic length. Conceptual models that include a hierarchical structure over a wide range of scales would be helpful for characterizing diverse behavior in different seismic regions and for improving probabilistic forecasts of earthquakes.

Geodetic Finite-Fault-based Earthquake Early Warning Performance for Great Earthquakes Worldwide

Science.gov (United States)

Ruhl, C. J.; Melgar, D.; Grapenthin, R.; Allen, R. M.

2017-12-01

GNSS-based earthquake early warning (EEW) algorithms estimate fault-finiteness and unsaturated moment magnitude for the largest, most damaging earthquakes. Because large events are infrequent, algorithms are not regularly exercised and insufficiently tested on few available datasets. The Geodetic Alarm System (G-larmS) is a GNSS-based finite-fault algorithm developed as part of the ShakeAlert EEW system in the western US. Performance evaluations using synthetic earthquakes offshore Cascadia showed that G-larmS satisfactorily recovers magnitude and fault length, providing useful alerts 30-40 s after origin time and timely warnings of ground motion for onshore urban areas. An end-to-end test of the ShakeAlert system demonstrated the need for GNSS data to accurately estimate ground motions in real-time. We replay real data from several subduction-zone earthquakes worldwide to demonstrate the value of GNSS-based EEW for the largest, most damaging events. We compare predicted ground acceleration (PGA) from first-alert-solutions with those recorded in major urban areas. In addition, where applicable, we compare observed tsunami heights to those predicted from the G-larmS solutions. We show that finite-fault inversion based on GNSS-data is essential to achieving the goals of EEW.

Safety and survival in an earthquake

Science.gov (United States)

,

1969-01-01

Many earth scientists in this country and abroad are focusing their studies on the search for means of predicting impending earthquakes, but, as yet, an accurate prediction of the time and place of such an event cannot be made. From past experience, however, one can assume that earthquakes will continue to harass mankind and that they will occur most frequently in the areas where they have been relatively common in the past. In the United States, earthquakes can be expected to occur most frequently in the western states, particularly in Alaska, California, Washington, Oregon, Nevada, Utah, and Montana. The danger, however, is not confined to any one part of the country; major earthquakes have occurred at widely scattered locations.

Low cost earthquake resistant ferrocement small house

International Nuclear Information System (INIS)

Saleem, M.A.; Ashraf, M.; Ashraf, M.

2008-01-01

The greatest humanitarian challenge faced even today after one year of Kashmir Hazara earthquake is that of providing shelter. Currently on the globe one in seven people live in a slum or refugee camp. The earthquake of October 2005 resulted in a great loss of life and property. This research work is mainly focused on developing a design of small size, low cost and earthquake resistant house. Ferrocement panels are recommended as the main structural elements with lightweight truss roofing system. Earthquake resistance is ensured by analyzing the structure on ETABS for a seismic activity of zone 4. The behavior of structure is found satisfactory under the earthquake loading. An estimate of cost is also presented which shows that it is an economical solution. (author)

Geological and historical evidence of irregular recurrent earthquakes in Japan.

Science.gov (United States)

Satake, Kenji

2015-10-28

Great (M∼8) earthquakes repeatedly occur along the subduction zones around Japan and cause fault slip of a few to several metres releasing strains accumulated from decades to centuries of plate motions. Assuming a simple 'characteristic earthquake' model that similar earthquakes repeat at regular intervals, probabilities of future earthquake occurrence have been calculated by a government committee. However, recent studies on past earthquakes including geological traces from giant (M∼9) earthquakes indicate a variety of size and recurrence interval of interplate earthquakes. Along the Kuril Trench off Hokkaido, limited historical records indicate that average recurrence interval of great earthquakes is approximately 100 years, but the tsunami deposits show that giant earthquakes occurred at a much longer interval of approximately 400 years. Along the Japan Trench off northern Honshu, recurrence of giant earthquakes similar to the 2011 Tohoku earthquake with an interval of approximately 600 years is inferred from historical records and tsunami deposits. Along the Sagami Trough near Tokyo, two types of Kanto earthquakes with recurrence interval of a few hundred years and a few thousand years had been recognized, but studies show that the recent three Kanto earthquakes had different source extents. Along the Nankai Trough off western Japan, recurrence of great earthquakes with an interval of approximately 100 years has been identified from historical literature, but tsunami deposits indicate that the sizes of the recurrent earthquakes are variable. Such variability makes it difficult to apply a simple 'characteristic earthquake' model for the long-term forecast, and several attempts such as use of geological data for the evaluation of future earthquake probabilities or the estimation of maximum earthquake size in each subduction zone are being conducted by government committees. © 2015 The Author(s).

Designing an Earthquake-Resistant Building

Science.gov (United States)

English, Lyn D.; King, Donna T.

2016-01-01

How do cross-bracing, geometry, and base isolation help buildings withstand earthquakes? These important structural design features involve fundamental geometry that elementary school students can readily model and understand. The problem activity, Designing an Earthquake-Resistant Building, was undertaken by several classes of sixth- grade…

The HayWired Earthquake Scenario

Science.gov (United States)

Detweiler, Shane T.; Wein, Anne M.

2017-04-24

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

Design basis earthquakes for critical industrial facilities and their characteristics, and the Southern Hyogo prefecture earthquake, 17 January 1995

Energy Technology Data Exchange (ETDEWEB)

Shibata, Heki

1998-12-01

This paper deals with how to establish the concept of the design basis earthquake (DBE) for critical industrial facilities such as nuclear power plants in consideration of disasters such as the Southern Hyogo prefecture earthquake, the so-called Kobe earthquake in 1995. The author once discussed various DBEs at the 7th World Conference on Earthquake Engineering. At that time, the author assumed that the strongest effective PGA would be 0.7 G, and compared the values of accelerations of a structure obtained by various codes in Japan and other countries. The maximum PGA observed by an instrument at the Southern Hyogo prefecture earthquake in 1995 exceeded the previous assumption of the author, even though the results of the previous paper had been pessimistic. According to the experience of the Kobe event, the author will point out the necessity of the third earthquake S{sub s} adding to S{sub 1} and S{sub 2} of previous DBEs.

The threat of silent earthquakes

Science.gov (United States)

Cervelli, Peter

2004-01-01

Not all earthquakes shake the ground. The so-called silent types are forcing scientists to rethink their understanding of the way quake-prone faults behave. In rare instances, silent earthquakes that occur along the flakes of seaside volcanoes may cascade into monstrous landslides that crash into the sea and trigger towering tsunamis. Silent earthquakes that take place within fault zones created by one tectonic plate diving under another may increase the chance of ground-shaking shocks. In other locations, however, silent slip may decrease the likelihood of destructive quakes, because they release stress along faults that might otherwise seem ready to snap.

Napa earthquake: An earthquake in a highly connected world

Science.gov (United States)

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

2014-12-01

The Napa earthquake recently occurred close to Silicon Valley. This makes it a good candidate to study what social networks, wearable objects and website traffic analysis (flashsourcing) can tell us about the way eyewitnesses react to ground shaking. In the first part, we compare the ratio of people publishing tweets and with the ratio of people visiting EMSC (European Mediterranean Seismological Centre) real time information website in the first minutes following the earthquake occurrence to the results published by Jawbone, which show that the proportion of people waking up depends (naturally) on the epicentral distance. The key question to evaluate is whether the proportions of inhabitants tweeting or visiting the EMSC website are similar to the proportion of people waking up as shown by the Jawbone data. If so, this supports the premise that all methods provide a reliable image of the relative ratio of people waking up. The second part of the study focuses on the reaction time for both Twitter and EMSC website access. We show, similarly to what was demonstrated for the Mineral, Virginia, earthquake (Bossu et al., 2014), that hit times on the EMSC website follow the propagation of the P waves and that 2 minutes of website traffic is sufficient to determine the epicentral location of an earthquake on the other side of the Atlantic. We also compare with the publication time of messages on Twitter. Finally, we check whether the number of tweets and the number of visitors relative to the number of inhabitants is correlated to the local level of shaking. Together these results will tell us whether the reaction of eyewitnesses to ground shaking as observed through Twitter and the EMSC website analysis is tool specific (i.e. specific to Twitter or EMSC website) or whether they do reflect people's actual reactions.

Electromagnetic Manifestation of Earthquakes

OpenAIRE

Uvarov Vladimir

2017-01-01

In a joint analysis of the results of recording the electrical component of the natural electromagnetic field of the Earth and the catalog of earthquakes in Kamchatka in 2013, unipolar pulses of constant amplitude associated with earthquakes were identified, whose activity is closely correlated with the energy of the electromagnetic field. For the explanation, a hypothesis about the cooperative character of these impulses is proposed.

Tidal controls on earthquake size-frequency statistics

Science.gov (United States)

Ide, S.; Yabe, S.; Tanaka, Y.

2016-12-01

The possibility that tidal stresses can trigger earthquakes is a long-standing issue in seismology. Except in some special cases, a causal relationship between seismicity and the phase of tidal stress has been rejected on the basis of studies using many small events. However, recently discovered deep tectonic tremors are highly sensitive to tidal stress levels, with the relationship being governed by a nonlinear law according to which the tremor rate increases exponentially with increasing stress; thus, slow deformation (and the probability of earthquakes) may be enhanced during periods of large tidal stress. Here, we show the influence of tidal stress on seismicity by calculating histories of tidal shear stress during the 2-week period before earthquakes. Very large earthquakes tend to occur near the time of maximum tidal stress, but this tendency is not obvious for small earthquakes. Rather, we found that tidal stress controls the earthquake size-frequency statistics; i.e., the fraction of large events increases (i.e. the b-value of the Gutenberg-Richter relation decreases) as the tidal shear stress increases. This correlation is apparent in data from the global catalog and in relatively homogeneous regional catalogues of earthquakes in Japan. The relationship is also reasonable, considering the well-known relationship between stress and the b-value. Our findings indicate that the probability of a tiny rock failure expanding to a gigantic rupture increases with increasing tidal stress levels. This finding has clear implications for probabilistic earthquake forecasting.

Earthquake-triggered landslides in southwest China

OpenAIRE

X. L. Chen; Q. Zhou; H. Ran; R. Dong

2012-01-01

Southwest China is located in the southeastern margin of the Tibetan Plateau and it is a region of high seismic activity. Historically, strong earthquakes that occurred here usually generated lots of landslides and brought destructive damages. This paper introduces several earthquake-triggered landslide events in this region and describes their characteristics. Also, the historical data of earthquakes with a magnitude of 7.0 or greater, having occurred in this region, is col...

Marmara Island earthquakes, of 1265 and 1935; Turkey

Directory of Open Access Journals (Sweden)

Y. Altınok

2006-01-01

Full Text Available The long-term seismicity of the Marmara Sea region in northwestern Turkey is relatively well-recorded. Some large and some of the smaller events are clearly associated with fault zones known to be seismically active, which have distinct morphological expressions and have generated damaging earthquakes before and later. Some less common and moderate size earthquakes have occurred in the vicinity of the Marmara Islands in the west Marmara Sea. This paper presents an extended summary of the most important earthquakes that have occurred in 1265 and 1935 and have since been known as the Marmara Island earthquakes. The informative data and the approaches used have therefore the potential of documenting earthquake ruptures of fault segments and may extend the records kept on earthquakes far before known history, rock falls and abnormal sea waves observed during these events, thus improving hazard evaluations and the fundamental understanding of the process of an earthquake.

Global Earthquake Hazard Frequency and Distribution

Data.gov (United States)

National Aeronautics and Space Administration — Global Earthquake Hazard Frequency and Distribution is a 2.5 minute grid utilizing Advanced National Seismic System (ANSS) Earthquake Catalog data of actual...

Fixed recurrence and slip models better predict earthquake behavior than the time- and slip-predictable models 1: repeating earthquakes

Science.gov (United States)

Rubinstein, Justin L.; Ellsworth, William L.; Chen, Kate Huihsuan; Uchida, Naoki

2012-01-01

The behavior of individual events in repeating earthquake sequences in California, Taiwan and Japan is better predicted by a model with fixed inter-event time or fixed slip than it is by the time- and slip-predictable models for earthquake occurrence. Given that repeating earthquakes are highly regular in both inter-event time and seismic moment, the time- and slip-predictable models seem ideally suited to explain their behavior. Taken together with evidence from the companion manuscript that shows similar results for laboratory experiments we conclude that the short-term predictions of the time- and slip-predictable models should be rejected in favor of earthquake models that assume either fixed slip or fixed recurrence interval. This implies that the elastic rebound model underlying the time- and slip-predictable models offers no additional value in describing earthquake behavior in an event-to-event sense, but its value in a long-term sense cannot be determined. These models likely fail because they rely on assumptions that oversimplify the earthquake cycle. We note that the time and slip of these events is predicted quite well by fixed slip and fixed recurrence models, so in some sense they are time- and slip-predictable. While fixed recurrence and slip models better predict repeating earthquake behavior than the time- and slip-predictable models, we observe a correlation between slip and the preceding recurrence time for many repeating earthquake sequences in Parkfield, California. This correlation is not found in other regions, and the sequences with the correlative slip-predictable behavior are not distinguishable from nearby earthquake sequences that do not exhibit this behavior.

Distribution of incremental static stress caused by earthquakes

Directory of Open Access Journals (Sweden)

Y. Y. Kagan

1994-01-01

Full Text Available Theoretical calculations, simulations and measurements of rotation of earthquake focal mechanisms suggest that the stress in earthquake focal zones follows the Cauchy distribution which is one of the stable probability distributions (with the value of the exponent α equal to 1. We review the properties of the stable distributions and show that the Cauchy distribution is expected to approximate the stress caused by earthquakes occurring over geologically long intervals of a fault zone development. However, the stress caused by recent earthquakes recorded in instrumental catalogues, should follow symmetric stable distributions with the value of α significantly less than one. This is explained by a fractal distribution of earthquake hypocentres: the dimension of a hypocentre set, ��, is close to zero for short-term earthquake catalogues and asymptotically approaches 2¼ for long-time intervals. We use the Harvard catalogue of seismic moment tensor solutions to investigate the distribution of incremental static stress caused by earthquakes. The stress measured in the focal zone of each event is approximated by stable distributions. In agreement with theoretical considerations, the exponent value of the distribution approaches zero as the time span of an earthquake catalogue (ΔT decreases. For large stress values α increases. We surmise that it is caused by the δ increase for small inter-earthquake distances due to location errors.

Summary of earthquake experience database

International Nuclear Information System (INIS)

1999-01-01

Strong-motion earthquakes frequently occur throughout the Pacific Basin, where power plants or industrial facilities are included in the affected areas. By studying the performance of these earthquake-affected (or database) facilities, a large inventory of various types of equipment installations can be compiled that have experienced substantial seismic motion. The primary purposes of the seismic experience database are summarized as follows: to determine the most common sources of seismic damage, or adverse effects, on equipment installations typical of industrial facilities; to determine the thresholds of seismic motion corresponding to various types of seismic damage; to determine the general performance of equipment during earthquakes, regardless of the levels of seismic motion; to determine minimum standards in equipment construction and installation, based on past experience, to assure the ability to withstand anticipated seismic loads. To summarize, the primary assumption in compiling an experience database is that the actual seismic hazard to industrial installations is best demonstrated by the performance of similar installations in past earthquakes

A new way of telling earthquake stories: MOBEE - the MOBile Earthquake Exhibition

Science.gov (United States)

Tataru, Dragos; Toma-Danila, Dragos; Nastase, Eduard

2016-04-01

In the last decades, the demand and acknowledged importance of science outreach, in general and geophysics in particular, has grown, as demonstrated by many international and national projects and other activities performed by research institutes. The National Institute for Earth Physics (NIEP) from Romania is the leading national institution on earthquake monitoring and research, having at the same time a declared focus on informing and educating a wide audience about geosciences and especially seismology. This is more than welcome, since Romania is a very active country from a seismological point of view, but not too reactive when it comes to diminishing the possible effect of a major earthquake. Over the last few decades, the country has experienced several major earthquakes which have claimed thousands of lives and millions in property damage (1940; 1977; 1986 and 1990 Vrancea earthquakes). In this context, during a partnership started in 2014 together with the National Art University and Siveco IT company, a group of researchers from NIEP initiated the MOBile Earthquake Exhibition (MOBEE) project. The main goal was to design a portable museum to bring on the road educational activities focused on seismology, seismic hazard and Earth science. The exhibition is mainly focused on school students of all ages as it explains the main topics of geophysics through a unique combination of posters, digital animations and apps, large markets and exciting hand-on experiments, 3D printed models and posters. This project is singular in Romania and aims to transmit properly reviewed actual information, regarding the definition of earthquakes, the way natural hazards can affect people, buildings and the environment and the measures to be taken for prevent an aftermath. Many of the presented concepts can be used by teachers as a complementary way of demonstrating physics facts and concepts and explaining processes that shape the dynamic Earth features. It also involves

Clinical characteristics of patients seizure following the 2016 Kumamoto earthquake.

Science.gov (United States)

Inatomi, Yuichiro; Nakajima, Makoto; Yonehara, Toshiro; Ando, Yukio

2017-06-01

To investigate the clinical characteristics of patients with seizure following the 2016 Kumamoto earthquake. We retrospectively studied patients with seizure admitted to our hospital for 12weeks following the earthquake. We compared the clinical backgrounds and characteristics of the patients: before (the same period from the previous 3years) and after the earthquake; and the early (first 2weeks) and late (subsequent 10weeks) phases. A total of 60 patients with seizure were admitted to the emergency room after the earthquake, and 175 (58.3/year) patients were admitted before the earthquake. Of them, 35 patients with seizure were hospitalized in the Department of Neurology after the earthquake, and 96 (32/year) patients were hospitalized before the earthquake. In patients after the earthquake, males and non-cerebrovascular diseases as an epileptogenic disease were seen more frequently than before the earthquake. During the early phase after the earthquake, female, first-attack, and non-focal-type patients were seen more frequently than during the late phase after the earthquake. These characteristics of patients with seizure during the early phase after the earthquake suggest that many patients had non-epileptic seizures. To prevent seizures following earthquakes, mental stress and physical status of evacuees must be assessed. Copyright © 2017. Published by Elsevier Ltd.

Small discussion of electromagnetic wave anomalies preceding earthquakes

Energy Technology Data Exchange (ETDEWEB)

1980-01-01

Six brief pieces on various aspects of electromagnetic wave anomalies are presented. They cover: earthquake electromagnetic emanations; the use of magnetic induction information for earthquake forecasting; electromagnetic pulse emissions as pre-earthquake indicators; the use of magnetic sensors to determine medium-wavelength field strength for earthquake prediction purposes; magnetic deviation indicators inside reinforced-concrete buildings; and a discussion of the general physical principles involved.

Ionospheric precursors to large earthquakes: A case study of the 2011 Japanese Tohoku Earthquake

Science.gov (United States)

Carter, B. A.; Kellerman, A. C.; Kane, T. A.; Dyson, P. L.; Norman, R.; Zhang, K.

2013-09-01

Researchers have reported ionospheric electron distribution abnormalities, such as electron density enhancements and/or depletions, that they claimed were related to forthcoming earthquakes. In this study, the Tohoku earthquake is examined using ionosonde data to establish whether any otherwise unexplained ionospheric anomalies were detected in the days and hours prior to the event. As the choices for the ionospheric baseline are generally different between previous works, three separate baselines for the peak plasma frequency of the F2 layer, foF2, are employed here; the running 30-day median (commonly used in other works), the International Reference Ionosphere (IRI) model and the Thermosphere Ionosphere Electrodynamic General Circulation Model (TIE-GCM). It is demonstrated that the classification of an ionospheric perturbation is heavily reliant on the baseline used, with the 30-day median, the IRI and the TIE-GCM generally underestimating, approximately describing and overestimating the measured foF2, respectively, in the 1-month period leading up to the earthquake. A detailed analysis of the ionospheric variability in the 3 days before the earthquake is then undertaken, where a simultaneous increase in foF2 and the Es layer peak plasma frequency, foEs, relative to the 30-day median was observed within 1 h before the earthquake. A statistical search for similar simultaneous foF2 and foEs increases in 6 years of data revealed that this feature has been observed on many other occasions without related seismic activity. Therefore, it is concluded that one cannot confidently use this type of ionospheric perturbation to predict an impending earthquake. It is suggested that in order to achieve significant progress in our understanding of seismo-ionospheric coupling, better account must be taken of other known sources of ionospheric variability in addition to solar and geomagnetic activity, such as the thermospheric coupling.

Investigating Landslides Caused by Earthquakes A Historical Review

Science.gov (United States)

Keefer, David K.

Post-earthquake field investigations of landslide occurrence have provided a basis for understanding, evaluating, and mapping the hazard and risk associated withearthquake-induced landslides. This paper traces thehistorical development of knowledge derived from these investigations. Before 1783, historical accounts of the occurrence of landslides in earthquakes are typically so incomplete and vague that conclusions based on these accounts are of limited usefulness. For example, the number of landslides triggered by a given event is almost always greatly underestimated. The first formal, scientific post-earthquake investigation that included systematic documentation of the landslides was undertaken in the Calabria region of Italy after the 1783 earthquake swarm. From then until the mid-twentieth century, the best information on earthquake-induced landslides came from a succession ofpost-earthquake investigations largely carried out by formal commissions that undertook extensive ground-based field studies. Beginning in the mid-twentieth century, when the use of aerial photography became widespread, comprehensive inventories of landslide occurrence have been made for several earthquakes in the United States, Peru, Guatemala, Italy, El Salvador, Japan, and Taiwan. Techniques have also been developed for performing ``retrospective'' analyses years or decades after an earthquake that attempt to reconstruct the distribution of landslides triggered by the event. The additional use of Geographic Information System (GIS) processing and digital mapping since about 1989 has greatly facilitated the level of analysis that can applied to mapped distributions of landslides. Beginning in 1984, syntheses of worldwide and national data on earthquake-induced landslides have defined their general characteristics and relations between their occurrence and various geologic and seismic parameters. However, the number of comprehensive post-earthquake studies of landslides is still

Aseismic blocks and destructive earthquakes in the Aegean

Science.gov (United States)

Stiros, Stathis

2017-04-01

Aseismic areas are not identified only in vast, geologically stable regions, but also within regions of active, intense, distributed deformation such as the Aegean. In the latter, "aseismic blocks" about 200m wide were recognized in the 1990's on the basis of the absence of instrumentally-derived earthquake foci, in contrast to surrounding areas. This pattern was supported by the available historical seismicity data, as well as by geologic evidence. Interestingly, GPS evidence indicates that such blocks are among the areas characterized by small deformation rates relatively to surrounding areas of higher deformation. Still, the largest and most destructive earthquake of the 1990's, the 1995 M6.6 earthquake occurred at the center of one of these "aseismic" zones at the northern part of Greece, found unprotected against seismic hazard. This case was indeed a repeat of the case of the tsunami-associated 1956 Amorgos Island M7.4 earthquake, the largest 20th century event in the Aegean back-arc region: the 1956 earthquake occurred at the center of a geologically distinct region (Cyclades Massif in Central Aegean), till then assumed aseismic. Interestingly, after 1956, the overall idea of aseismic regions remained valid, though a "promontory" of earthquake prone-areas intruding into the aseismic central Aegean was assumed. Exploitation of the archaeological excavation evidence and careful, combined analysis of historical and archaeological data and other palaeoseismic, mostly coastal data, indicated that destructive and major earthquakes have left their traces in previously assumed aseismic blocks. In the latter earthquakes typically occur with relatively low recurrence intervals, >200-300 years, much smaller than in adjacent active areas. Interestingly, areas assumed a-seismic in antiquity are among the most active in the last centuries, while areas hit by major earthquakes in the past are usually classified as areas of low seismic risk in official maps. Some reasons

Tsunami evacuation plans for future megathrust earthquakes in Padang, Indonesia, considering stochastic earthquake scenarios

Directory of Open Access Journals (Sweden)

A. Muhammad

2017-12-01

Full Text Available This study develops tsunami evacuation plans in Padang, Indonesia, using a stochastic tsunami simulation method. The stochastic results are based on multiple earthquake scenarios for different magnitudes (Mw 8.5, 8.75, and 9.0 that reflect asperity characteristics of the 1797 historical event in the same region. The generation of the earthquake scenarios involves probabilistic models of earthquake source parameters and stochastic synthesis of earthquake slip distributions. In total, 300 source models are generated to produce comprehensive tsunami evacuation plans in Padang. The tsunami hazard assessment results show that Padang may face significant tsunamis causing the maximum tsunami inundation height and depth of 15 and 10 m, respectively. A comprehensive tsunami evacuation plan – including horizontal evacuation area maps, assessment of temporary shelters considering the impact due to ground shaking and tsunami, and integrated horizontal–vertical evacuation time maps – has been developed based on the stochastic tsunami simulation results. The developed evacuation plans highlight that comprehensive mitigation policies can be produced from the stochastic tsunami simulation for future tsunamigenic events.

POST Earthquake Debris Management — AN Overview

Science.gov (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

A Decade of Giant Earthquakes - What does it mean?

Energy Technology Data Exchange (ETDEWEB)

Wallace, Terry C. Jr. [Los Alamos National Laboratory

2012-07-16

On December 26, 2004 the largest earthquake since 1964 occurred near Ache, Indonesia. The magnitude 9.2 earthquake and subsequent tsunami killed a quarter of million people; it also marked the being of a period of extraordinary seismicity. Since the Ache earthquake there have been 16 magnitude 8 earthquakes globally, including 2 this last April. For the 100 years previous to 2004 there was an average of 1 magnitude 8 earthquake every 2.2 years; since 2004 there has been 2 per year. Since magnitude 8 earthquakes dominate global seismic energy release, this period of seismicity has seismologist rethinking what they understand about plate tectonics and the connectivity between giant earthquakes. This talk will explore this remarkable period of time and its possible implications.

Electromagnetic Manifestation of Earthquakes

Directory of Open Access Journals (Sweden)

Uvarov Vladimir

2017-01-01

Full Text Available In a joint analysis of the results of recording the electrical component of the natural electromagnetic field of the Earth and the catalog of earthquakes in Kamchatka in 2013, unipolar pulses of constant amplitude associated with earthquakes were identified, whose activity is closely correlated with the energy of the electromagnetic field. For the explanation, a hypothesis about the cooperative character of these impulses is proposed.

Relationship of heat and cold to earthquakes

Energy Technology Data Exchange (ETDEWEB)

Chen, Y.

1980-06-26

An analysis of 54 earthquakes of magnitude 7 and above, including 13 of magnitude 8 and above, between 780 BC and the present, shows that the vast majority of them fell in the four major cool periods during this time span, or on the boundaries of these periods. Between 1800 and 1876, four periods of earthquake activity in China can be recognized, and these tend to correspond to relatively cold periods over that time span. An analysis of earthquakes of magnitude 6 or above over the period 1951 to 1965 gives the following results: earthquakes in north and southwest China tended to occur when the preceding year had an above-average annual temperature and winter temperature; in the northeast they tended to occur in a year after a year with an above-average winter temperature; in the northwest there was also a connection with a preceding warm winter, but to a less pronounced degree. The few earthquakes in South China seemed to follow cold winters. Both the Tangshan and Yongshan Pass earthquakes were preceded by unusually warm years and relatively high winter temperatures.

Studies of the subsurface effects of earthquakes

International Nuclear Information System (INIS)

Marine, I.W.

1980-01-01

As part of the National Terminal Waste Storage Program, the Savannah River Laboratory is conducting a series of studies on the subsurface effects of earthquakes. This report summarizes three subcontracted studies. (1) Earthquake damage to underground facilities: the purpose of this study was to document damage and nondamage caused by earthquakes to tunnels and shallow underground openings; to mines and other deep openings; and to wells, shafts, and other vertical facilities. (2) Earthquake related displacement fields near underground facilities: the study included an analysis of block motion, an analysis of the dependence of displacement on the orientation and distance of joints from the earthquake source, and displacement related to distance and depth near a causative fault as a result of various shapes, depths, and senses of movement on the causative fault. (3) Numerical simulation of earthquake effects on tunnels for generic nuclear waste repositories: the objective of this study was to use numerical modeling to determine under what conditions seismic waves might cause instability of an underground opening or create fracturing that would increase the permeability of the rock mass

Earthquake risk assessment of building structures

International Nuclear Information System (INIS)

Ellingwood, Bruce R.

2001-01-01

During the past two decades, probabilistic risk analysis tools have been applied to assess the performance of new and existing building structural systems. Structural design and evaluation of buildings and other facilities with regard to their ability to withstand the effects of earthquakes requires special considerations that are not normally a part of such evaluations for other occupancy, service and environmental loads. This paper reviews some of these special considerations, specifically as they pertain to probability-based codified design and reliability-based condition assessment of existing buildings. Difficulties experienced in implementing probability-based limit states design criteria for earthquake are summarized. Comparisons of predicted and observed building damage highlight the limitations of using current deterministic approaches for post-earthquake building condition assessment. The importance of inherent randomness and modeling uncertainty in forecasting building performance is examined through a building fragility assessment of a steel frame with welded connections that was damaged during the Northridge Earthquake of 1994. The prospects for future improvements in earthquake-resistant design procedures based on a more rational probability-based treatment of uncertainty are examined

Evaluation of Earthquake-Induced Effects on Neighbouring Faults and Volcanoes: Application to the 2016 Pedernales Earthquake

Science.gov (United States)

Bejar, M.; Alvarez Gomez, J. A.; Staller, A.; Luna, M. P.; Perez Lopez, R.; Monserrat, O.; Chunga, K.; Herrera, G.; Jordá, L.; Lima, A.; Martínez-Díaz, J. J.

2017-12-01

It has long been recognized that earthquakes change the stress in the upper crust around the fault rupture and can influence the short-term behaviour of neighbouring faults and volcanoes. Rapid estimates of these stress changes can provide the authorities managing the post-disaster situation with a useful tool to identify and monitor potential threads and to update the estimates of seismic and volcanic hazard in a region. Space geodesy is now routinely used following an earthquake to image the displacement of the ground and estimate the rupture geometry and the distribution of slip. Using the obtained source model, it is possible to evaluate the remaining moment deficit and to infer the stress changes on nearby faults and volcanoes produced by the earthquake, which can be used to identify which faults and volcanoes are brought closer to failure or activation. Although these procedures are commonly used today, the transference of these results to the authorities managing the post-disaster situation is not straightforward and thus its usefulness is reduced in practice. Here we propose a methodology to evaluate the potential influence of an earthquake on nearby faults and volcanoes and create easy-to-understand maps for decision-making support after an earthquake. We apply this methodology to the Mw 7.8, 2016 Ecuador earthquake. Using Sentinel-1 SAR and continuous GPS data, we measure the coseismic ground deformation and estimate the distribution of slip. Then we use this model to evaluate the moment deficit on the subduction interface and changes of stress on the surrounding faults and volcanoes. The results are compared with the seismic and volcanic events that have occurred after the earthquake. We discuss potential and limits of the methodology and the lessons learnt from discussion with local authorities.

Soil structure interactions of eastern U.S. type earthquakes

International Nuclear Information System (INIS)

Chang Chen; Serhan, S.

1991-01-01

Two types of earthquakes have occurred in the eastern US in the past. One of them was the infrequent major events such as the 1811-1812 New Madrid Earthquakes, or the 1886 Charleston Earthquake. The other type was the frequent shallow earthquakes with high frequency, short duration and high accelerations. Two eastern US nuclear power plants, V.C Summer and Perry, went through extensive licensing effort to obtain fuel load licenses after this type of earthquake was recorded on sites and exceeded the design bases beyond 10 hertz region. This paper discusses the soil-structure interactions of the latter type of earthquakes

Has El Salvador Fault Zone produced M ≥ 7.0 earthquakes? The 1719 El Salvador earthquake

Science.gov (United States)

Canora, C.; Martínez-Díaz, J.; Álvarez-Gómez, J.; Villamor, P.; Ínsua-Arévalo, J.; Alonso-Henar, J.; Capote, R.

2013-05-01

Historically, large earthquakes, Mw ≥ 7.0, in the Εl Salvador area have been attributed to activity in the Cocos-Caribbean subduction zone. Τhis is correct for most of the earthquakes of magnitude greater than 6.5. However, recent paleoseismic evidence points to the existence of large earthquakes associated with rupture of the Εl Salvador Fault Ζone, an Ε-W oriented strike slip fault system that extends for 150 km through central Εl Salvador. Τo calibrate our results from paleoseismic studies, we have analyzed the historical seismicity of the area. In particular, we suggest that the 1719 earthquake can be associated with paleoseismic activity evidenced in the Εl Salvador Fault Ζone. Α reinterpreted isoseismal map for this event suggests that the damage reported could have been a consequence of the rupture of Εl Salvador Fault Ζone, rather than rupture of the subduction zone. Τhe isoseismal is not different to other upper crustal earthquakes in similar tectonovolcanic environments. We thus challenge the traditional assumption that only the subduction zone is capable of generating earthquakes of magnitude greater than 7.0 in this region. Τhis result has broad implications for future risk management in the region. Τhe potential occurrence of strong ground motion, significantly higher and closer to the Salvadorian populations that those assumed to date, must be considered in seismic hazard assessment studies in this area.

Earthquake prediction the ory and its relation to precursors

International Nuclear Information System (INIS)

Negarestani, A.; Setayeshi, S.; Ghannadi-Maragheh, M.; Akasheh, B.

2001-01-01

Since we don't have enough knowledge about the Physics of earthquakes. therefore. the study of seismic precursors plays an important role in earthquake prediction. Earthquake prediction is a science which discusses about precursory phenomena during seismogenic process, and then investigates the correlation and association among them and the intrinsic relation between precursors and the seismogenic process. ar the end judges comprehensively the seismic status and finally makes earthquake prediction. There are two ways for predicting earthquake prediction. The first is to study the physics of seismogenic process and to determine the parameters in the process based on the source theories and the second way is to use seismic precursors. In this paper the theory of earthquake is reviewed. We also study theory of earthquake using models of earthquake origin, the relation between seismogenic process and various accompanying precursory phenomena. The earthquake prediction is divided into three categories: long-term, medium-term and short-term. We study seismic anomalous behavior. electric field, crustal deformation, gravity. magnetism of earth. change of groundwater variation. groundwater geochemistry and change of Radon gas emission. Finally, it is concluded the there is a correlation between Radon gas emission and earthquake phenomena. Meanwhile, there are some samples from actual processing in this area

Global Significant Earthquake Database, 2150 BC to present

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — The Significant Earthquake Database is a global listing of over 5,700 earthquakes from 2150 BC to the present. A significant earthquake is classified as one that...

The 2010 Chile Earthquake: Rapid Assessments of Tsunami

OpenAIRE

Michelini, A.; Lauciani, V.; Selvaggi, G.; Lomax, A.

2010-01-01

After an earthquake underwater, rapid real-time assessment of earthquake parameters is important for emergency response related to infrastructure damage and, perhaps more exigently, for issuing warnings of the possibility of an impending tsunami. Since 2005, the Istituto Nazionale di Geofisica e Vulcanologia (INGV) has worked on the rapid quantification of earthquake magnitude and tsunami potential, especially for the Mediterranean area. This work includes quantification of earthquake size fr...

Collaboratory for the Study of Earthquake Predictability

Science.gov (United States)

Schorlemmer, D.; Jordan, T. H.; Zechar, J. D.; Gerstenberger, M. C.; Wiemer, S.; Maechling, P. J.

2006-12-01

Earthquake prediction is one of the most difficult problems in physical science and, owing to its societal implications, one of the most controversial. The study of earthquake predictability has been impeded by the lack of an adequate experimental infrastructure---the capability to conduct scientific prediction experiments under rigorous, controlled conditions and evaluate them using accepted criteria specified in advance. To remedy this deficiency, the Southern California Earthquake Center (SCEC) is working with its international partners, which include the European Union (through the Swiss Seismological Service) and New Zealand (through GNS Science), to develop a virtual, distributed laboratory with a cyberinfrastructure adequate to support a global program of research on earthquake predictability. This Collaboratory for the Study of Earthquake Predictability (CSEP) will extend the testing activities of SCEC's Working Group on Regional Earthquake Likelihood Models, from which we will present first results. CSEP will support rigorous procedures for registering prediction experiments on regional and global scales, community-endorsed standards for assessing probability-based and alarm-based predictions, access to authorized data sets and monitoring products from designated natural laboratories, and software to allow researchers to participate in prediction experiments. CSEP will encourage research on earthquake predictability by supporting an environment for scientific prediction experiments that allows the predictive skill of proposed algorithms to be rigorously compared with standardized reference methods and data sets. It will thereby reduce the controversies surrounding earthquake prediction, and it will allow the results of prediction experiments to be communicated to the scientific community, governmental agencies, and the general public in an appropriate research context.

Simulated earthquake ground motions

International Nuclear Information System (INIS)

Vanmarcke, E.H.; Gasparini, D.A.

1977-01-01

The paper reviews current methods for generating synthetic earthquake ground motions. Emphasis is on the special requirements demanded of procedures to generate motions for use in nuclear power plant seismic response analysis. Specifically, very close agreement is usually sought between the response spectra of the simulated motions and prescribed, smooth design response spectra. The features and capabilities of the computer program SIMQKE, which has been widely used in power plant seismic work are described. Problems and pitfalls associated with the use of synthetic ground motions in seismic safety assessment are also pointed out. The limitations and paucity of recorded accelerograms together with the widespread use of time-history dynamic analysis for obtaining structural and secondary systems' response have motivated the development of earthquake simulation capabilities. A common model for synthesizing earthquakes is that of superposing sinusoidal components with random phase angles. The input parameters for such a model are, then, the amplitudes and phase angles of the contributing sinusoids as well as the characteristics of the variation of motion intensity with time, especially the duration of the motion. The amplitudes are determined from estimates of the Fourier spectrum or the spectral density function of the ground motion. These amplitudes may be assumed to be varying in time or constant for the duration of the earthquake. In the nuclear industry, the common procedure is to specify a set of smooth response spectra for use in aseismic design. This development and the need for time histories have generated much practical interest in synthesizing earthquakes whose response spectra 'match', or are compatible with a set of specified smooth response spectra

Seismic methodology in determining basis earthquake for nuclear installation

International Nuclear Information System (INIS)

Ameli Zamani, Sh.

2008-01-01

Design basis earthquake ground motions for nuclear installations should be determined to assure the design purpose of reactor safety: that reactors should be built and operated to pose no undue risk to public health and safety from earthquake and other hazards. Regarding the influence of seismic hazard to a site, large numbers of earthquake ground motions can be predicted considering possible variability among the source, path, and site parameters. However, seismic safety design using all predicted ground motions is practically impossible. In the determination of design basis earthquake ground motions it is therefore important to represent the influences of the large numbers of earthquake ground motions derived from the seismic ground motion prediction methods for the surrounding seismic sources. Viewing the relations between current design basis earthquake ground motion determination and modem earthquake ground motion estimation, a development of risk-informed design basis earthquake ground motion methodology is discussed for insight into the on going modernization of the Examination Guide for Seismic Design on NPP

Land-Ocean-Atmospheric Coupling Associated with Earthquakes

Science.gov (United States)

Prasad, A. K.; Singh, R. P.; Kumar, S.; Cervone, G.; Kafatos, M.; Zlotnicki, J.

2007-12-01

Earthquakes are well known to occur along the plate boundaries and also on the stable shield. The recent studies have shown existence of strong coupling between land-ocean-atmospheric parameters associated with the earthquakes. We have carried out detailed analysis of multi sensor data (optical and microwave remote) to show existence of strong coupling between land-ocean-atmospheric parameters associated with the earthquakes with focal depth up to 30 km and magnitude greater than 5.5. Complimentary nature of various land, ocean and atmospheric parameters will be demonstrated in getting an early warning information about an impending earthquake.

a Collaborative Cyberinfrastructure for Earthquake Seismology

Science.gov (United States)

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

2013-12-01

One of the challenges in real time seismology is the prediction of earthquake's impact. It is particularly true for moderate earthquake (around magnitude 6) located close to urbanised areas, where the slightest uncertainty in event location, depth, magnitude estimates, and/or misevaluation of propagation characteristics, site effects and buildings vulnerability can dramatically change impact scenario. The Euro-Med Seismological Centre (EMSC) has developed a cyberinfrastructure to collect observations from eyewitnesses in order to provide in-situ constraints on actual damages. This cyberinfrastructure takes benefit of the natural convergence of earthquake's eyewitnesses on EMSC website (www.emsc-csem.org), the second global earthquake information website within tens of seconds of the occurrence of a felt event. It includes classical crowdsourcing tools such as online questionnaires available in 39 languages, and tools to collect geolocated pics. It also comprises information derived from the real time analysis of the traffic on EMSC website, a method named flashsourcing; In case of a felt earthquake, eyewitnesses reach EMSC website within tens of seconds to find out the cause of the shaking they have just been through. By analysing their geographical origin through their IP address, we automatically detect felt earthquakes and in some cases map the damaged areas through the loss of Internet visitors. We recently implemented a Quake Catcher Network (QCN) server in collaboration with Stanford University and the USGS, to collect ground motion records performed by volunteers and are also involved in a project to detect earthquakes from ground motions sensors from smartphones. Strategies have been developed for several social media (Facebook, Twitter...) not only to distribute earthquake information, but also to engage with the Citizens and optimise data collection. A smartphone application is currently under development. We will present an overview of this

Pain after earthquake

Directory of Open Access Journals (Sweden)

Angeletti Chiara

2012-06-01

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.

Strong motion duration and earthquake magnitude relationships

International Nuclear Information System (INIS)

Salmon, M.W.; Short, S.A.; Kennedy, R.P.

1992-06-01

Earthquake duration is the total time of ground shaking from the arrival of seismic waves until the return to ambient conditions. Much of this time is at relatively low shaking levels which have little effect on seismic structural response and on earthquake damage potential. As a result, a parameter termed ''strong motion duration'' has been defined by a number of investigators to be used for the purpose of evaluating seismic response and assessing the potential for structural damage due to earthquakes. This report presents methods for determining strong motion duration and a time history envelope function appropriate for various evaluation purposes, for earthquake magnitude and distance, and for site soil properties. There are numerous definitions of strong motion duration. For most of these definitions, empirical studies have been completed which relate duration to earthquake magnitude and distance and to site soil properties. Each of these definitions recognizes that only the portion of an earthquake record which has sufficiently high acceleration amplitude, energy content, or some other parameters significantly affects seismic response. Studies have been performed which indicate that the portion of an earthquake record in which the power (average rate of energy input) is maximum correlates most closely with potential damage to stiff nuclear power plant structures. Hence, this report will concentrate on energy based strong motion duration definitions

Visible Earthquakes: a web-based tool for visualizing and modeling InSAR earthquake data

Science.gov (United States)

Funning, G. J.; Cockett, R.

2012-12-01

InSAR (Interferometric Synthetic Aperture Radar) is a technique for measuring the deformation of the ground using satellite radar data. One of the principal applications of this method is in the study of earthquakes; in the past 20 years over 70 earthquakes have been studied in this way, and forthcoming satellite missions promise to enable the routine and timely study of events in the future. Despite the utility of the technique and its widespread adoption by the research community, InSAR does not feature in the teaching curricula of most university geoscience departments. This is, we believe, due to a lack of accessibility to software and data. Existing tools for the visualization and modeling of interferograms are often research-oriented, command line-based and/or prohibitively expensive. Here we present a new web-based interactive tool for comparing real InSAR data with simple elastic models. The overall design of this tool was focused on ease of access and use. This tool should allow interested nonspecialists to gain a feel for the use of such data and greatly facilitate integration of InSAR into upper division geoscience courses, giving students practice in comparing actual data to modeled results. The tool, provisionally named 'Visible Earthquakes', uses web-based technologies to instantly render the displacement field that would be observable using InSAR for a given fault location, geometry, orientation, and slip. The user can adjust these 'source parameters' using a simple, clickable interface, and see how these affect the resulting model interferogram. By visually matching the model interferogram to a real earthquake interferogram (processed separately and included in the web tool) a user can produce their own estimates of the earthquake's source parameters. Once satisfied with the fit of their models, users can submit their results and see how they compare with the distribution of all other contributed earthquake models, as well as the mean and median

Earthquake Preparedness Among Japanese Hemodialysis Patients in Prefectures Heavily Damaged by the 2011 Great East Japan Earthquake.

Science.gov (United States)

Sugisawa, Hidehiro; Shimizu, Yumiko; Kumagai, Tamaki; Sugisaki, Hiroaki; Ohira, Seiji; Shinoda, Toshio

2017-08-01

The purpose of this study was to explore the factors related to earthquake preparedness in Japanese hemodialysis patients. We focused on three aspects of the related factors: health condition factors, social factors, and the experience of disasters. A mail survey of all the members of the Japan Association of Kidney Disease Patients in three Japanese prefectures (N = 4085) was conducted in March, 2013. We obtained 1841 valid responses for analysis. The health factors covered were: activities of daily living (ADL), mental distress, primary renal diseases, and the duration of dialysis. The social factors were: socioeconomic status, family structure, informational social support, and the provision of information regarding earthquake preparedness from dialysis facilities. The results show that the average percentage of participants that had met each criterion of earthquake preparedness in 2013 was 53%. Hemodialysis patients without disabled ADL, without mental distress, and requiring longer periods of dialysis, were likely to meet more of the earthquake preparedness criteria. Hemodialysis patients who had received informational social support from family or friends, had lived with spouse and children in comparison to living alone, and had obtained information regarding earthquake preparedness from dialysis facilities, were also likely to meet more of the earthquake preparedness criteria. © 2017 International Society for Apheresis, Japanese Society for Apheresis, and Japanese Society for Dialysis Therapy.

Combining multiple earthquake models in real time for earthquake early warning

Science.gov (United States)

Minson, Sarah E.; Wu, Stephen; Beck, James L; Heaton, Thomas H.

2017-01-01

The ultimate goal of earthquake early warning (EEW) is to provide local shaking information to users before the strong shaking from an earthquake reaches their location. This is accomplished by operating one or more real‐time analyses that attempt to predict shaking intensity, often by estimating the earthquake’s location and magnitude and then predicting the ground motion from that point source. Other EEW algorithms use finite rupture models or may directly estimate ground motion without first solving for an earthquake source. EEW performance could be improved if the information from these diverse and independent prediction models could be combined into one unified, ground‐motion prediction. In this article, we set the forecast shaking at each location as the common ground to combine all these predictions and introduce a Bayesian approach to creating better ground‐motion predictions. We also describe how this methodology could be used to build a new generation of EEW systems that provide optimal decisions customized for each user based on the user’s individual false‐alarm tolerance and the time necessary for that user to react.

Earthquake Complex Network Analysis Before and After the Mw 8.2 Earthquake in Iquique, Chile

Science.gov (United States)

Pasten, D.

2017-12-01

The earthquake complex networks have shown that they are abble to find specific features in seismic data set. In space, this networkshave shown a scale-free behavior for the probability distribution of connectivity, in directed networks and theyhave shown a small-world behavior, for the undirected networks.In this work, we present an earthquake complex network analysis for the large earthquake Mw 8.2 in the north ofChile (near to Iquique) in April, 2014. An earthquake complex network is made dividing the three dimensional space intocubic cells, if one of this cells contain an hypocenter, we name this cell like a node. The connections between nodes aregenerated in time. We follow the time sequence of seismic events and we are making the connections betweennodes. Now, we have two different networks: a directed and an undirected network. Thedirected network takes in consideration the time-direction of the connections, that is very important for the connectivityof the network: we are considering the connectivity, ki of the i-th node, like the number of connections going out ofthe node i plus the self-connections (if two seismic events occurred successive in time in the same cubic cell, we havea self-connection). The undirected network is made removing the direction of the connections and the self-connectionsfrom the directed network. For undirected networks, we are considering only if two nodes are or not connected.We have built a directed complex network and an undirected complex network, before and after the large earthquake in Iquique. We have used magnitudes greater than Mw = 1.0 and Mw = 3.0. We found that this method can recognize the influence of thissmall seismic events in the behavior of the network and we found that the size of the cell used to build the network isanother important factor to recognize the influence of the large earthquake in this complex system. This method alsoshows a difference in the values of the critical exponent γ (for the probability

Make an Earthquake: Ground Shaking!

Science.gov (United States)

Savasci, Funda

2011-01-01

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,…

Engineering geological aspect of Gorkha Earthquake 2015, Nepal

Science.gov (United States)

Adhikari, Basanta Raj; Andermann, Christoff; Cook, Kristen

2016-04-01

Strong shaking by earthquake causes massif landsliding with severe effects on infrastructure and human lives. The distribution of landslides and other hazards are depending on the combination of earthquake and local characteristics which influence the dynamic response of hillslopes. The Himalayas are one of the most active mountain belts with several kilometers of relief and is very prone to catastrophic mass failure. Strong and shallow earthquakes are very common and cause wide spread collapse of hillslopes, increasing the background landslide rate by several magnitude. The Himalaya is facing many small and large earthquakes in the past i.e. earthquakes i.e. Bihar-Nepal earthquake 1934 (Ms 8.2); Large Kangra earthquake of 1905 (Ms 7.8); Gorkha earthquake 2015 (Mw 7.8). The Mw 7.9 Gorkha earthquake has occurred on and around the main Himalayan Thrust with a hypocentral depth of 15 km (GEER 2015) followed by Mw 7.3 aftershock in Kodari causing 8700+ deaths and leaving hundreds of thousands of homeless. Most of the 3000 aftershocks located by National Seismological Center (NSC) within the first 45 days following the Gorkha Earthquake are concentrated in a narrow 40 km-wide band at midcrustal to shallow depth along the strike of the southern slope of the high Himalaya (Adhikari et al. 2015) and the ground shaking was substantially lower in the short-period range than would be expected for and earthquake of this magnitude (Moss et al. 2015). The effect of this earthquake is very unique in affected areas by showing topographic effect, liquefaction and land subsidence. More than 5000 landslides were triggered by this earthquake (Earthquake without Frontiers, 2015). Most of the landslides are shallow and occurred in weathered bedrock and appear to have mobilized primarily as raveling failures, rock slides and rock falls. Majority of landslides are limited to a zone which runs east-west, approximately parallel the lesser and higher Himalaya. There are numerous cracks in

Salient Features of the 2015 Gorkha, Nepal Earthquake in Relation to Earthquake Cycle and Dynamic Rupture Models

Science.gov (United States)

Ampuero, J. P.; Meng, L.; Hough, S. E.; Martin, S. S.; Asimaki, D.

2015-12-01

Two salient features of the 2015 Gorkha, Nepal, earthquake provide new opportunities to evaluate models of earthquake cycle and dynamic rupture. The Gorkha earthquake broke only partially across the seismogenic depth of the Main Himalayan Thrust: its slip was confined in a narrow depth range near the bottom of the locked zone. As indicated by the belt of background seismicity and decades of geodetic monitoring, this is an area of stress concentration induced by deep fault creep. Previous conceptual models attribute such intermediate-size events to rheological segmentation along-dip, including a fault segment with intermediate rheology in between the stable and unstable slip segments. We will present results from earthquake cycle models that, in contrast, highlight the role of stress loading concentration, rather than frictional segmentation. These models produce "super-cycles" comprising recurrent characteristic events interspersed by deep, smaller non-characteristic events of overall increasing magnitude. Because the non-characteristic events are an intrinsic component of the earthquake super-cycle, the notion of Coulomb triggering or time-advance of the "big one" is ill-defined. The high-frequency (HF) ground motions produced in Kathmandu by the Gorkha earthquake were weaker than expected for such a magnitude and such close distance to the rupture, as attested by strong motion recordings and by macroseismic data. Static slip reached close to Kathmandu but had a long rise time, consistent with control by the along-dip extent of the rupture. Moreover, the HF (1 Hz) radiation sources, imaged by teleseismic back-projection of multiple dense arrays calibrated by aftershock data, was deep and far from Kathmandu. We argue that HF rupture imaging provided a better predictor of shaking intensity than finite source inversion. The deep location of HF radiation can be attributed to rupture over heterogeneous initial stresses left by the background seismic activity

Global volcanic earthquake swarm database and preliminary analysis of volcanic earthquake swarm duration

Directory of Open Access Journals (Sweden)

S. R. McNutt

1996-06-01

Full Text Available Global data from 1979 to 1989 pertaining to volcanic earthquake swarms have been compiled into a custom-designed relational database. The database is composed of three sections: 1 a section containing general information on volcanoes, 2 a section containing earthquake swarm data (such as dates of swarm occurrence and durations, and 3 a section containing eruption information. The most abundant and reliable parameter, duration of volcanic earthquake swarms, was chosen for preliminary analysis. The distribution of all swarm durations was found to have a geometric mean of 5.5 days. Precursory swarms were then separated from those not associated with eruptions. The geometric mean precursory swarm duration was 8 days whereas the geometric mean duration of swarms not associated with eruptive activity was 3.5 days. Two groups of precursory swarms are apparent when duration is compared with the eruption repose time. Swarms with durations shorter than 4 months showed no clear relationship with the eruption repose time. However, the second group, lasting longer than 4 months, showed a significant positive correlation with the log10 of the eruption repose period. The two groups suggest that different suites of physical processes are involved in the generation of volcanic earthquake swarms.

Sensitivity of tsunami wave profiles and inundation simulations to earthquake slip and fault geometry for the 2011 Tohoku earthquake

KAUST Repository

Goda, Katsuichiro; Mai, Paul Martin; Yasuda, Tomohiro; Mori, Nobuhito

2014-01-01

In this study, we develop stochastic random-field slip models for the 2011 Tohoku earthquake and conduct a rigorous sensitivity analysis of tsunami hazards with respect to the uncertainty of earthquake slip and fault geometry. Synthetic earthquake slip distributions generated from the modified Mai-Beroza method captured key features of inversion-based source representations of the mega-thrust event, which were calibrated against rich geophysical observations of this event. Using original and synthesised earthquake source models (varied for strike, dip, and slip distributions), tsunami simulations were carried out and the resulting variability in tsunami hazard estimates was investigated. The results highlight significant sensitivity of the tsunami wave profiles and inundation heights to the coastal location and the slip characteristics, and indicate that earthquake slip characteristics are a major source of uncertainty in predicting tsunami risks due to future mega-thrust events.

Sensitivity of tsunami wave profiles and inundation simulations to earthquake slip and fault geometry for the 2011 Tohoku earthquake

KAUST Repository

Goda, Katsuichiro

2014-09-01

In this study, we develop stochastic random-field slip models for the 2011 Tohoku earthquake and conduct a rigorous sensitivity analysis of tsunami hazards with respect to the uncertainty of earthquake slip and fault geometry. Synthetic earthquake slip distributions generated from the modified Mai-Beroza method captured key features of inversion-based source representations of the mega-thrust event, which were calibrated against rich geophysical observations of this event. Using original and synthesised earthquake source models (varied for strike, dip, and slip distributions), tsunami simulations were carried out and the resulting variability in tsunami hazard estimates was investigated. The results highlight significant sensitivity of the tsunami wave profiles and inundation heights to the coastal location and the slip characteristics, and indicate that earthquake slip characteristics are a major source of uncertainty in predicting tsunami risks due to future mega-thrust events.

Enhanced Earthquake-Resistance on the High Level Radioactive Waste Canister

International Nuclear Information System (INIS)

Choi, Youngchul; Yoon, Chanhoon; Lee, Jeaowan; Kim, Jinsup; Choi, Heuijoo

2014-01-01

In this paper, the earthquake-resistance type buffer was developed with the method protecting safely about the earthquake. The main parameter having an effect on the earthquake-resistant performance was analyzed and the earthquake-proof type buffer material was designed. The shear analysis model was developed and the performance of the earthquake-resistance buffer material was evaluated. The dynamic behavior of the radioactive waste disposal canister was analyzed in case the earthquake was generated. In the case, the disposal canister gets the serious damage. In this paper, the earthquake-resistance buffer material was developed in order to prevent this damage. By putting the buffer in which the density is small between the canister and buffer, the earthquake-resistant performance was improved about 80%

A Case Study of the Bam Earthquake to Establish a Pattern for Earthquake Management in Iran

Directory of Open Access Journals (Sweden)

Keramatollah Ziari

2015-03-01

Full Text Available The field of crisis management knowledge and expertise is associated with a wide range of fields. Knowledge-based crisis management is a combination of science, art and practice. Iran is an earthquake-prone country. Through years several earthquakes have happened in the country resulting in many human and financial losses. According to scientific standards, the first 24 hours following an earthquake is the most valuable time for saving victims. Yet in the case of Bam only 5% of the victims were rescued within the first 48 hours. The success of disaster management is evaluated in terms of programming, raising public participation, organizing and hiring manpower, and supervising the management process. In this study disaster management is divided into three stages in which different actions are required. The stages and actions are explained in detail. Moreover, features, effects, and losses of the earthquake are described.

75 FR 66388 - Scientific Earthquake Studies Advisory Committee

Science.gov (United States)

2010-10-28

..., including the multi-hazards demonstration project and earthquake early warning prototype development. The... DEPARTMENT OF THE INTERIOR U.S. Geological Survey [USGS-GX11GG009950000] Scientific Earthquake... Public Law 106-503, the Scientific Earthquake Studies Advisory Committee (SESAC) will hold its next...

75 FR 2159 - Scientific Earthquake Studies Advisory Committee

Science.gov (United States)

2010-01-14

... DEPARTMENT OF THE INTERIOR U.S. Geological Survey Scientific Earthquake Studies Advisory Committee... Scientific Earthquake Studies Advisory Committee (SESAC) will hold its next meeting at the U.S. Geological... participation in the National Earthquake Hazards Reduction Program. The Committee will receive updates and...

Earthquake geology of the Bulnay Fault (Mongolia)

Science.gov (United States)

Rizza, Magali; Ritz, Jean-Franciois; Prentice, Carol S.; Vassallo, Ricardo; Braucher, Regis; Larroque, Christophe; Arzhannikova, A.; Arzhanikov, S.; Mahan, Shannon; Massault, M.; Michelot, J-L.; Todbileg, M.

2015-01-01

The Bulnay earthquake of July 23, 1905 (Mw 8.3-8.5), in north-central Mongolia, is one of the world's largest recorded intracontinental earthquakes and one of four great earthquakes that occurred in the region during the 20th century. The 375-km-long surface rupture of the left-lateral, strike-slip, N095°E trending Bulnay Fault associated with this earthquake is remarkable for its pronounced expression across the landscape and for the size of features produced by previous earthquakes. Our field observations suggest that in many areas the width and geometry of the rupture zone is the result of repeated earthquakes; however, in those areas where it is possible to determine that the geomorphic features are the result of the 1905 surface rupture alone, the size of the features produced by this single earthquake are singular in comparison to most other historical strike-slip surface ruptures worldwide. Along the 80 km stretch, between 97.18°E and 98.33°E, the fault zone is characterized by several meters width and the mean left-lateral 1905 offset is 8.9 ± 0.6 m with two measured cumulative offsets that are twice the 1905 slip. These observations suggest that the displacement produced during the penultimate event was similar to the 1905 slip. Morphotectonic analyses carried out at three sites along the eastern part of the Bulnay fault, allow us to estimate a mean horizontal slip rate of 3.1 ± 1.7 mm/yr over the Late Pleistocene-Holocene period. In parallel, paleoseismological investigations show evidence for two earthquakes prior to the 1905 event with recurrence intervals of ~2700-4000 years.

Method for forecasting an earthquake from precursor signals

International Nuclear Information System (INIS)

Farnworth, D.F.

1996-01-01

A method for forecasting an earthquake from precursor signals by employing characteristic first electromagnetic signals, second, seismically induced electromagnetic signals, seismically induced mechanical signals, and infrasonic acoustic signals which have been observed to precede an earthquake. From a first electromagnetic signal, a magnitude, depth beneath the surface of the earth, distance, latitude, longitude, and first and second forecasts of the time of occurrence of the impending earthquake may be derived. From a second, seismically induced electromagnetic signal and the mechanical signal, third and fourth forecasts of the time of occurrence of an impending earthquake determined from the analysis above, a magnitude, depth beneath the surface of the earth and fourth and fifth forecasts of the time of occurrence of the impending earthquake may be derived. The forecasts of time available from the above analyses range from up to five weeks to substantially within one hour in advance of the earthquake. (author)

Unbonded Prestressed Columns for Earthquake Resistance

Science.gov (United States)

2012-05-01

Modern structures are able to survive significant shaking caused by earthquakes. By implementing unbonded post-tensioned tendons in bridge columns, the damage caused by an earthquake can be significantly lower than that of a standard reinforced concr...

Incorporating human-triggered earthquake risks into energy and water policies

Science.gov (United States)

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

2010-12-01

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.

The October 1992 Parkfield, California, earthquake prediction

Science.gov (United States)

Langbein, J.

1992-01-01

A magnitude 4.7 earthquake occurred near Parkfield, California, on October 20, 992, at 05:28 UTC (October 19 at 10:28 p.m. local or Pacific Daylight Time).This moderate shock, interpreted as the potential foreshock of a damaging earthquake on the San Andreas fault, triggered long-standing federal, state and local government plans to issue a public warning of an imminent magnitude 6 earthquake near Parkfield. Although the predicted earthquake did not take place, sophisticated suites of instruments deployed as part of the Parkfield Earthquake Prediction Experiment recorded valuable data associated with an unusual series of events. this article describes the geological aspects of these events, which occurred near Parkfield in October 1992. The accompnaying article, an edited version of a press conference b Richard Andrews, the Director of the California Office of Emergency Service (OES), describes governmental response to the prediction.   

Oklahoma’s recent earthquakes and saltwater disposal

Science.gov (United States)

Walsh, F. Rall; Zoback, Mark D.

2015-01-01

Over the past 5 years, parts of Oklahoma have experienced marked increases in the number of small- to moderate-sized earthquakes. In three study areas that encompass the vast majority of the recent seismicity, we show that the increases in seismicity follow 5- to 10-fold increases in the rates of saltwater disposal. Adjacent areas where there has been relatively little saltwater disposal have had comparatively few recent earthquakes. In the areas of seismic activity, the saltwater disposal principally comes from “produced” water, saline pore water that is coproduced with oil and then injected into deeper sedimentary formations. These formations appear to be in hydraulic communication with potentially active faults in crystalline basement, where nearly all the earthquakes are occurring. Although most of the recent earthquakes have posed little danger to the public, the possibility of triggering damaging earthquakes on potentially active basement faults cannot be discounted. PMID:26601200

Implications of fault constitutive properties for earthquake prediction.

Science.gov (United States)

Dieterich, J H; Kilgore, B

1996-04-30

The rate- and state-dependent constitutive formulation for fault slip characterizes an exceptional variety of materials over a wide range of sliding conditions. This formulation provides a unified representation of diverse sliding phenomena including slip weakening over a characteristic sliding distance Dc, apparent fracture energy at a rupture front, time-dependent healing after rapid slip, and various other transient and slip rate effects. Laboratory observations and theoretical models both indicate that earthquake nucleation is accompanied by long intervals of accelerating slip. Strains from the nucleation process on buried faults generally could not be detected if laboratory values of Dc apply to faults in nature. However, scaling of Dc is presently an open question and the possibility exists that measurable premonitory creep may precede some earthquakes. Earthquake activity is modeled as a sequence of earthquake nucleation events. In this model, earthquake clustering arises from sensitivity of nucleation times to the stress changes induced by prior earthquakes. The model gives the characteristic Omori aftershock decay law and assigns physical interpretation to aftershock parameters. The seismicity formulation predicts large changes of earthquake probabilities result from stress changes. Two mechanisms for foreshocks are proposed that describe observed frequency of occurrence of foreshock-mainshock pairs by time and magnitude. With the first mechanism, foreshocks represent a manifestation of earthquake clustering in which the stress change at the time of the foreshock increases the probability of earthquakes at all magnitudes including the eventual mainshock. With the second model, accelerating fault slip on the mainshock nucleation zone triggers foreshocks.

Statistical aspects and risks of human-caused earthquakes

Science.gov (United States)

Klose, C. D.

2013-12-01

The seismological community invests ample human capital and financial resources to research and predict risks associated with earthquakes. Industries such as the insurance and re-insurance sector are equally interested in using probabilistic risk models developed by the scientific community to transfer risks. These models are used to predict expected losses due to naturally occurring earthquakes. But what about the risks associated with human-caused earthquakes? Such risk models are largely absent from both industry and academic discourse. In countries around the world, informed citizens are becoming increasingly aware and concerned that this economic bias is not sustainable for long-term economic growth, environmental and human security. Ultimately, citizens look to their government officials to hold industry accountable. In the Netherlands, for example, the hydrocarbon industry is held accountable for causing earthquakes near Groningen. In Switzerland, geothermal power plants were shut down or suspended because they caused earthquakes in canton Basel and St. Gallen. The public and the private non-extractive industry needs access to information about earthquake risks in connection with sub/urban geoengineeing activities, including natural gas production through fracking, geothermal energy production, carbon sequestration, mining and water irrigation. This presentation illuminates statistical aspects of human-caused earthquakes with respect to different geologic environments. Statistical findings are based on the first catalog of human-caused earthquakes (in Klose 2013). Findings are discussed which include the odds to die during a medium-size earthquake that is set off by geomechanical pollution. Any kind of geoengineering activity causes this type of pollution and increases the likelihood of triggering nearby faults to rupture.

Historical earthquake investigations in Greece

Directory of Open Access Journals (Sweden)

K. Makropoulos

2004-06-01

Full Text Available The active tectonics of the area of Greece and its seismic activity have always been present in the country?s history. Many researchers, tempted to work on Greek historical earthquakes, have realized that this is a task not easily fulfilled. The existing catalogues of strong historical earthquakes are useful tools to perform general SHA studies. However, a variety of supporting datasets, non-uniformly distributed in space and time, need to be further investigated. In the present paper, a review of historical earthquake studies in Greece is attempted. The seismic history of the country is divided into four main periods. In each one of them, characteristic examples, studies and approaches are presented.

Crowd-Sourced Global Earthquake Early Warning

Science.gov (United States)

Minson, S. E.; Brooks, B. A.; Glennie, C. L.; Murray, J. R.; Langbein, J. O.; Owen, S. E.; Iannucci, B. A.; Hauser, D. L.

2014-12-01

Although earthquake early warning (EEW) has shown great promise for reducing loss of life and property, it has only been implemented in a few regions due, in part, to the prohibitive cost of building the required dense seismic and geodetic networks. However, many cars and consumer smartphones, tablets, laptops, and similar devices contain low-cost versions of the same sensors used for earthquake monitoring. If a workable EEW system could be implemented based on either crowd-sourced observations from consumer devices or very inexpensive networks of instruments built from consumer-quality sensors, EEW coverage could potentially be expanded worldwide. Controlled tests of several accelerometers and global navigation satellite system (GNSS) receivers typically found in consumer devices show that, while they are significantly noisier than scientific-grade instruments, they are still accurate enough to capture displacements from moderate and large magnitude earthquakes. The accuracy of these sensors varies greatly depending on the type of data collected. Raw coarse acquisition (C/A) code GPS data are relatively noisy. These observations have a surface displacement detection threshold approaching ~1 m and would thus only be useful in large Mw 8+ earthquakes. However, incorporating either satellite-based differential corrections or using a Kalman filter to combine the raw GNSS data with low-cost acceleration data (such as from a smartphone) decreases the noise dramatically. These approaches allow detection thresholds as low as 5 cm, potentially enabling accurate warnings for earthquakes as small as Mw 6.5. Simulated performance tests show that, with data contributed from only a very small fraction of the population, a crowd-sourced EEW system would be capable of warning San Francisco and San Jose of a Mw 7 rupture on California's Hayward fault and could have accurately issued both earthquake and tsunami warnings for the 2011 Mw 9 Tohoku-oki, Japan earthquake.

Cyclic characteristics of earthquake time histories

International Nuclear Information System (INIS)

Hall, J.R. Jr; Shukla, D.K.; Kissenpfennig, J.F.

1977-01-01

From an engineering standpoint, an earthquake record may be characterized by a number of parameters, one of which is its 'cyclic characteristics'. The cyclic characteristics are most significant in fatigue analysis of structures and liquefaction analysis of soils where, in addition to the peak motion, cyclic buildup is significant. Whereas duration peak amplitude and response spectra for earthquakes have been studied extensively, the cyclic characteristics of earthquake records have not received an equivalent attention. Present procedures to define the cyclic characteristics are generally based upon counting the number of peaks at various amplitude ranges on a record. This paper presents a computer approach which describes a time history by an amplitude envelope and a phase curve. Using Fast Fourier Transform Techniques, an earthquake time history is represented as a projection along the x-axis of a rotating vector-the length the vector is given by the amplitude spectra-and the angle between the vector and x-axis is given by the phase curve. Thus one cycle is completed when the vector makes a full rotation. Based upon Miner's cumulative damage concept, the computer code automatically combines the cycles of various amplitudes to obtain the equivalent number of cycles of a given amplitude. To illustrate the overall results, the cyclic characteristics of several real and synthetic earthquake time histories have been studied and are presented in the paper, with the conclusion that this procedure provides a physical interpretation of the cyclic characteristics of earthquakes. (Auth.)

A Deterministic Approach to Earthquake Prediction

Directory of Open Access Journals (Sweden)

Vittorio Sgrigna

2012-01-01

Full Text Available The paper aims at giving suggestions for a deterministic approach to investigate possible earthquake prediction and warning. A fundamental contribution can come by observations and physical modeling of earthquake precursors aiming at seeing in perspective the phenomenon earthquake within the framework of a unified theory able to explain the causes of its genesis, and the dynamics, rheology, and microphysics of its preparation, occurrence, postseismic relaxation, and interseismic phases. Studies based on combined ground and space observations of earthquake precursors are essential to address the issue. Unfortunately, up to now, what is lacking is the demonstration of a causal relationship (with explained physical processes and looking for a correlation between data gathered simultaneously and continuously by space observations and ground-based measurements. In doing this, modern and/or new methods and technologies have to be adopted to try to solve the problem. Coordinated space- and ground-based observations imply available test sites on the Earth surface to correlate ground data, collected by appropriate networks of instruments, with space ones detected on board of Low-Earth-Orbit (LEO satellites. Moreover, a new strong theoretical scientific effort is necessary to try to understand the physics of the earthquake.

78 FR 19004 - Scientific Earthquake Studies Advisory Committee

Science.gov (United States)

2013-03-28

... Hazards Program. Focus topics for this meeting include induced seismicity, earthquake early warning and... DEPARTMENT OF THE INTERIOR U.S. Geological Survey [GX13GG009950000] Scientific Earthquake Studies... Law 106-503, the Scientific Earthquake Studies Advisory Committee (SESAC) will hold its next meeting...

The role of post-earthquake structural safety in pre-earthquake retrof in decision: guidelines and applications

International Nuclear Information System (INIS)

Bazzurro, P.; Telleen, K.; Maffei, J.; Yin, J.; Cornell, C.A.

2009-01-01

Critical structures such as hospitals, police stations, local administrative office buildings, and critical lifeline facilities, are expected to be operational immediately after earthquakes. Any rational decision about whether these structures are strong enough to meet this goal or whether pre-empitive retrofitting is needed cannot be made without an explicit consideration of post-earthquake safety and functionality with respect to aftershocks. Advanced Seismic Assessment Guidelines offer improvement over previous methods for seismic evaluation of buildings where post-earthquake safety and usability is a concern. This new method allows engineers to evaluate the like hood that a structure may have restricted access or no access after an earthquake. The building performance is measured in terms of the post-earthquake occupancy classifications Green Tag, Yellow Tag, and Red Tag, defining these performance levels quantitatively, based on the structure's remaining capacity to withstand aftershocks. These color-coded placards that constitute an established practice in US could be replaced by the standard results of inspections (A to E) performed by the Italian Dept. of Civil Protection after an event. The article also shows some applications of these Guidelines to buildings of the largest utility company in California, Pacific Gas and Electric Company (PGE). [it

Tilt Precursors before Earthquakes on the San Andreas Fault, California.

Science.gov (United States)

Johnston, M J; Mortensen, C E

1974-12-13

An array of 14 biaxial shallow-borehole tiltmeters (at 1O(-7) radian sensitivity) has been installed along 85 kilometers of the San Andreas fault during the past year. Earthquake-related changes in tilt have been simultaneously observed on up to four independent instruments. At earthquake distances greater than 10 earthquake source dimensions, there are few clear indications of tilt change. For the four instruments with the longest records (> 10 months), 26 earthquakes have occurred since July 1973 with at least one instrument closer than 10 source dimensions and 8 earthquakes with more than one instrument within that distance. Precursors in tilt direction have been observed before more than 10 earthquakes or groups of earthquakes, and no similar effect has yet been seen without the occurrence of an earthquake.

The Differences in Source Dynamics Between Intermediate-Depth and Deep EARTHQUAKES:A Comparative Study Between the 2014 Rat Islands Intermediate-Depth Earthquake and the 2015 Bonin Islands Deep Earthquake

Science.gov (United States)

Twardzik, C.; Ji, C.

2015-12-01

It has been proposed that the mechanisms for intermediate-depth and deep earthquakes might be different. While previous extensive seismological studies suggested that such potential differences do not significantly affect the scaling relationships of earthquake parameters, there has been only a few investigations regarding their dynamic characteristics, especially for fracture energy. In this work, the 2014 Mw7.9 Rat Islands intermediate-depth (105 km) earthquake and the 2015 Mw7.8 Bonin Islands deep (680 km) earthquake are studied from two different perspectives. First, their kinematic rupture models are constrained using teleseismic body waves. Our analysis reveals that the Rat Islands earthquake breaks the entire cold core of the subducting slab defined as the depth of the 650oC isotherm. The inverted stress drop is 4 MPa, compatible to that of intra-plate earthquakes at shallow depths. On the other hand, the kinematic rupture model of the Bonin Islands earthquake, which occurred in a region lacking of seismicity for the past forty years, according to the GCMT catalog, exhibits an energetic rupture within a 35 km by 30 km slip patch and a high stress drop of 24 MPa. It is of interest to note that although complex rupture patterns are allowed to match the observations, the inverted slip distributions of these two earthquakes are simple enough to be approximated as the summation of a few circular/elliptical slip patches. Thus, we investigate subsequently their dynamic rupture models. We use a simple modelling approach in which we assume that the dynamic rupture propagation obeys a slip-weakening friction law, and we describe the distribution of stress and friction on the fault as a set of elliptical patches. We will constrain the three dynamic parameters that are yield stress, background stress prior to the rupture and slip weakening distance, as well as the shape of the elliptical patches directly from teleseismic body waves observations. The study would help us

Earthquakes Threaten Many American Schools

Science.gov (United States)

Bailey, Nancy E.

2010-01-01

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…

Solar eruptions - soil radon - earthquakes

International Nuclear Information System (INIS)

Saghatelyan, E.; Petrosyan, L.; Aghbalyan, Yu.; Baburyan, M.; Araratyan, L.

2004-01-01

For the first time a new natural phenomenon was established: a contrasting increase in the soil radon level under the influence of solar flares. Such an increase is one of geochemical indicators of earthquakes. Most researchers consider this a phenomenon of exclusively terrestrial processes. Investigations regarding the link of earthquakes to solar activity carried out during the last decade in different countries are based on the analysis of statistical data ΣΕ (t) and W (t). As established, the overall seismicity of the Earth and its separate regions depends of an 11-year long cycle of solar activity. Data provided in the paper based on experimental studies serve the first step on the way of experimental data on revealing cause-and-reason solar-terrestrials bonds in a series s olar eruption-lithosphere radon-earthquakes . They need further collection of experimental data. For the first time, through radon constituent of terrestrial radiation objectification has been made of elementary lattice of the Hartmann's network contoured out by bio location method. As found out, radon concentration variations in Hartmann's network nodes determine the dynamics of solar-terrestrial relationships. Of the three types of rapidly running processes conditioned by solar-terrestrial bonds earthquakes are attributed to rapidly running destructive processes that occur in the most intense way at the juncture of tectonic massifs, along transformed and deep failures. The basic factors provoking the earthquakes are both magnetic-structural effects and a long-term (over 5 months) bombing of the surface of lithosphere by highly energetic particles of corpuscular solar flows, this being approved by photometry. As a result of solar flares that occurred from 29 October to 4 November 2003, a sharply contrasting increase in soil radon was established which is an earthquake indicator on the territory of Yerevan City. A month and a half later, earthquakes occurred in San-Francisco, Iran, Turkey

Do I Really Sound Like That? Communicating Earthquake Science Following Significant Earthquakes at the NEIC

Science.gov (United States)

Hayes, G. P.; Earle, P. S.; Benz, H.; Wald, D. J.; Yeck, W. L.

2017-12-01

The U.S. Geological Survey's National Earthquake Information Center (NEIC) responds to about 160 magnitude 6.0 and larger earthquakes every year and is regularly inundated with information requests following earthquakes that cause significant impact. These requests often start within minutes after the shaking occurs and come from a wide user base including the general public, media, emergency managers, and government officials. Over the past several years, the NEIC's earthquake response has evolved its communications strategy to meet the changing needs of users and the evolving media landscape. The NEIC produces a cascade of products starting with basic hypocentral parameters and culminating with estimates of fatalities and economic loss. We speed the delivery of content by prepositioning and automatically generating products such as, aftershock plots, regional tectonic summaries, maps of historical seismicity, and event summary posters. Our goal is to have information immediately available so we can quickly address the response needs of a particular event or sequence. This information is distributed to hundreds of thousands of users through social media, email alerts, programmatic data feeds, and webpages. Many of our products are included in event summary posters that can be downloaded and printed for local display. After significant earthquakes, keeping up with direct inquiries and interview requests from TV, radio, and print reports is always challenging. The NEIC works with the USGS Office of Communications and the USGS Science Information Services to organize and respond to these requests. Written executive summaries reports are produced and distributed to USGS personnel and collaborators throughout the country. These reports are updated during the response to keep our message consistent and information up to date. This presentation will focus on communications during NEIC's rapid earthquake response but will also touch on the broader USGS traditional and

Earthquake safety program at Lawrence Livermore National Laboratory

International Nuclear Information System (INIS)

Freeland, G.E.

1985-01-01

Within three minutes on the morning of January 24, 1980, an earthquake and three aftershocks, with Richter magnitudes of 5.8, 5.1, 4.0, and 4.2, respectively, struck the Livermore Valley. Two days later, a Richter magnitude 5.4 earthquake occurred, which had its epicenter about 4 miles northwest of the Lawrence Livermore National Laboratory (LLNL). Although no one at the Lab was seriously injured, these earthquakes caused considerable damage and disruption. Masonry and concrete structures cracked and broke, trailers shifted and fell off their pedestals, office ceilings and overhead lighting fell, and bookcases overturned. The Laboratory was suddenly immersed in a site-wide program of repairing earthquake-damaged facilities, and protecting our many employees and the surrounding community from future earthquakes. Over the past five years, LLNL has spent approximately $10 million on its earthquake restoration effort for repairs and upgrades. The discussion in this paper centers upon the earthquake damage that occurred, the clean-up and restoration efforts, the seismic review of LLNL facilities, our site-specific seismic design criteria, computer-floor upgrades, ceiling-system upgrades, unique building seismic upgrades, geologic and seismologic studies, and seismic instrumentation. 10 references

A contrast study of the traumatic condition between the wounded in 5.12 Wenchuan earthquake and 4.25 Nepal earthquake.

Science.gov (United States)

Ding, Sheng; Hu, Yonghe; Zhang, Zhongkui; Wang, Ting

2015-01-01

5.12 Wenchuan earthquake and 4.25 Nepal earthquake are of the similar magnitude, but the climate and geographic environment are totally different. Our team carried out medical rescue in both disasters, so we would like to compare the different traumatic conditions of the wounded in two earthquakes. The clinical data of the wounded respectively in 5.12 Wenchuan earthquake and 4.25 Nepal earthquake rescued by Chengdu Military General Hospital were retrospectively analyzed. Then a contrast study between the wounded was conducted in terms of age, sex, injury mechanisms, traumatic conditions, complications and prognosis. Three days after 5.12 Wenchuan earthquake, 465 cases of the wounded were hospitalized in Chengdu Military General Hospital, including 245 males (52.7%) and 220 females (47.3%) with the average age of (47.6±22.7) years. Our team carried out humanitarian relief in Katmandu after 4.25 Nepal earthquake. Three days after this disaster, 71 cases were treated in our field hospital, including 37 males (52.1%) and 34 females (47.9%) with the mean age of (44.8±22.9) years. There was no obvious difference in sex and mean age between two groups, but the age distribution was a little different: there were more wounded people at the age over 60 years in 4.25 Nepal earthquake (pearthquake (pearthquake had a higher rate of bruise injury and crush injury (pearthquake had a higher rate of falling injury (pearthquake, 4.25 Nepal earthquake has a much higher incidence of limb fractures (pearthquakes of the similar magnitude can cause different injury mechanisms, traumatic conditions and complications in the wounded under different climate and geographic environment.When an earthquake occurs in a poor traffic area of high altitude and large temperature difference, early medical rescue, injury control and wounded evacuation as well as sufficient warmth retention and food supply are of vital significance.

Earthquake free design of pipe lines

International Nuclear Information System (INIS)

Kurihara, Chizuko; Sakurai, Akio

1974-01-01

Long structures such as cooling sea water pipe lines of nuclear power plants have a wide range of extent along the ground surface, and are incurred by not only the inertia forces but also forces due to ground deformations or the seismic wave propagation during earthquakes. Since previous reports indicated the earthquake free design of underground pipe lines, it is discussed in this report on behaviors of pipe lines on the ground during earthquakes and is proposed the aseismic design of pipe lines considering the effects of both inertia forces and ground deformations. (author)

Toward standardization of slow earthquake catalog -Development of database website-

Science.gov (United States)

Kano, M.; Aso, N.; Annoura, S.; Arai, R.; Ito, Y.; Kamaya, N.; Maury, J.; Nakamura, M.; Nishimura, T.; Obana, K.; Sugioka, H.; Takagi, R.; Takahashi, T.; Takeo, A.; Yamashita, Y.; Matsuzawa, T.; Ide, S.; Obara, K.

2017-12-01

Slow earthquakes have now been widely discovered in the world based on the recent development of geodetic and seismic observations. Many researchers detect a wide frequency range of slow earthquakes including low frequency tremors, low frequency earthquakes, very low frequency earthquakes and slow slip events by using various methods. Catalogs of the detected slow earthquakes are open to us in different formats by each referring paper or through a website (e.g., Wech 2010; Idehara et al. 2014). However, we need to download catalogs from different sources, to deal with unformatted catalogs and to understand the characteristics of different catalogs, which may be somewhat complex especially for those who are not familiar with slow earthquakes. In order to standardize slow earthquake catalogs and to make such a complicated work easier, Scientific Research on Innovative Areas "Science of Slow Earthquakes" has been developing a slow earthquake catalog website. In the website, we can plot locations of various slow earthquakes via the Google Maps by compiling a variety of slow earthquake catalogs including slow slip events. This enables us to clearly visualize spatial relations among slow earthquakes at a glance and to compare the regional activities of slow earthquakes or the locations of different catalogs. In addition, we can download catalogs in the unified format and refer the information on each catalog on the single website. Such standardization will make it more convenient for users to utilize the previous achievements and to promote research on slow earthquakes, which eventually leads to collaborations with researchers in various fields and further understanding of the mechanisms, environmental conditions, and underlying physics of slow earthquakes. Furthermore, we expect that the website has a leading role in the international standardization of slow earthquake catalogs. We report the overview of the website and the progress of construction. Acknowledgment: This

Stress triggering and the Canterbury earthquake sequence

Science.gov (United States)

Steacy, Sandy; Jiménez, Abigail; Holden, Caroline

2014-01-01

The Canterbury earthquake sequence, which includes the devastating Christchurch event of 2011 February, has to date led to losses of around 40 billion NZ dollars. The location and severity of the earthquakes was a surprise to most inhabitants as the seismic hazard model was dominated by an expected Mw > 8 earthquake on the Alpine fault and an Mw 7.5 earthquake on the Porters Pass fault, 150 and 80 km to the west of Christchurch. The sequence to date has included an Mw = 7.1 earthquake and 3 Mw ≥ 5.9 events which migrated from west to east. Here we investigate whether the later events are consistent with stress triggering and whether a simple stress map produced shortly after the first earthquake would have accurately indicated the regions where the subsequent activity occurred. We find that 100 per cent of M > 5.5 earthquakes occurred in positive stress areas computed using a slip model for the first event that was available within 10 d of its occurrence. We further find that the stress changes at the starting points of major slip patches of post-Darfield main events are consistent with triggering although this is not always true at the hypocentral locations. Our results suggest that Coulomb stress changes contributed to the evolution of the Canterbury sequence and we note additional areas of increased stress in the Christchurch region and on the Porters Pass fault.

USGS Tweet Earthquake Dispatch (@USGSted): Using Twitter for Earthquake Detection and Characterization

Science.gov (United States)

Liu, S. B.; Bouchard, B.; Bowden, D. C.; Guy, M.; Earle, P.

2012-12-01

The U.S. Geological Survey (USGS) is investigating how online social networking services like Twitter—a microblogging service for sending and reading public text-based messages of up to 140 characters—can augment USGS earthquake response products and the delivery of hazard information. The USGS Tweet Earthquake Dispatch (TED) system is using Twitter not only to broadcast seismically-verified earthquake alerts via the @USGSted and @USGSbigquakes Twitter accounts, but also to rapidly detect widely felt seismic events through a real-time detection system. The detector algorithm scans for significant increases in tweets containing the word "earthquake" or its equivalent in other languages and sends internal alerts with the detection time, tweet text, and the location of the city where most of the tweets originated. It has been running in real-time for 7 months and finds, on average, two or three felt events per day with a false detection rate of less than 10%. The detections have reasonable coverage of populated areas globally. The number of detections is small compared to the number of earthquakes detected seismically, and only a rough location and qualitative assessment of shaking can be determined based on Tweet data alone. However, the Twitter detections are generally caused by widely felt events that are of more immediate interest than those with no human impact. The main benefit of the tweet-based detections is speed, with most detections occurring between 19 seconds and 2 minutes from the origin time. This is considerably faster than seismic detections in poorly instrumented regions of the world. Going beyond the initial detection, the USGS is developing data mining techniques to continuously archive and analyze relevant tweets for additional details about the detected events. The information generated about an event is displayed on a web-based map designed using HTML5 for the mobile environment, which can be valuable when the user is not able to access a

Public perceptions and acceptance of induced earthquakes related to energy development

International Nuclear Information System (INIS)

McComas, Katherine A.; Lu, Hang; Keranen, Katie M.; Furtney, Maria A.; Song, Hwansuck

2016-01-01

Growing awareness of the potential for some energy-related activities to induce earthquakes has created a need to understand how the public evaluates the risks of induced earthquakes versus the benefits of energy development. To address this need, this study presents a web survey that used a between-subjects factorial experimental design to explore the views of 325 U.S. adults, who were asked about their experiences with earthquakes; risk perceptions related to different causes of earthquakes (e.g., natural versus induced); and acceptability of earthquakes depending on the benefits, beneficiaries, and decision making process. The results found that participants had more negative feelings toward induced versus naturally occurring earthquakes. Although they judged no earthquake as “acceptable,” participants rated induced earthquakes significantly less acceptable than naturally occurring ones. Attributing the benefits to the provision of renewable energy or climate change mitigation did not increase induced earthquake acceptability, and no particular beneficiary made earthquakes more acceptable, although private companies as beneficiaries made earthquakes less acceptable. Finally, induced earthquake acceptability was significantly higher when people believed that people like them had a voice in the decision to implement the technology that caused the earthquake, underscoring the importance of public engagement in the development of energy technologies. - Highlights: • Human induced earthquakes were perceived as more negative than natural earthquakes. • Attributing benefits to renewable energy did not increase earthquake acceptability. • Acceptability was highest after a procedurally fair decision making process. • Acceptability was lowest following an expert-driven decision.

Simulation analysis of earthquake response of nuclear power plant to the 2003 Miyagi-Oki earthquake

International Nuclear Information System (INIS)

Yoshihiro Ogata; Kiyoshi Hirotani; Masayuki Higuchi; Shingo Nakayama

2005-01-01

On May 26, 2003 an earthquake of magnitude scale 7.1 (Japan Meteorological Agency) occurred just offshore of Miyagi Prefecture. This was the largest earthquake ever experienced by the nuclear power plant of Tohoku Electric Power Co. in Onagawa (hereafter the Onagawa Nuclear Power Plant) during the 19 years since it had started operations in 1984. In this report, we review the vibration characteristics of the reactor building of the Onagawa Nuclear Power Plant Unit 1 based on acceleration records observed at the building, and give an account of a simulation analysis of the earthquake response carried out to ascertain the appropriateness of design procedure and a seismic safety of the building. (authors)

Simulation of the earthquake-induced collapse of a school building in Turkey in 2011 Van Earthquake

NARCIS (Netherlands)

Bal, Ihsan Engin; Smyrou, Eleni

2016-01-01

Collapses of school or dormitory buildings experienced in recent earthquakes raise the issue of safety as a major challenge for decision makers. A school building is ‘just another structure’ technically speaking, however, the consequences of a collapse in an earthquake could lead to social reactions

Fault Branching and Long-Term Earthquake Rupture Scenario for Strike-Slip Earthquake

Science.gov (United States)

Klinger, Y.; CHOI, J. H.; Vallage, A.

2017-12-01

Careful examination of surface rupture for large continental strike-slip earthquakes reveals that for the majority of earthquakes, at least one major branch is involved in the rupture pattern. Often, branching might be either related to the location of the epicenter or located toward the end of the rupture, and possibly related to the stopping of the rupture. In this work, we examine large continental earthquakes that show significant branches at different scales and for which ground surface rupture has been mapped in great details. In each case, rupture conditions are described, including dynamic parameters, past earthquakes history, and regional stress orientation, to see if the dynamic stress field would a priori favor branching. In one case we show that rupture propagation and branching are directly impacted by preexisting geological structures. These structures serve as pathways for the rupture attempting to propagate out of its shear plane. At larger scale, we show that in some cases, rupturing a branch might be systematic, hampering possibilities for the development of a larger seismic rupture. Long-term geomorphology hints at the existence of a strong asperity in the zone where the rupture branched off the main fault. There, no evidence of throughgoing rupture could be seen along the main fault, while the branch is well connected to the main fault. This set of observations suggests that for specific configurations, some rupture scenarios involving systematic branching are more likely than others.

Earthquake location in island arcs

Science.gov (United States)

Engdahl, E.R.; Dewey, J.W.; Fujita, K.

1982-01-01

A comprehensive data set of selected teleseismic P-wave arrivals and local-network P- and S-wave arrivals from large earthquakes occurring at all depths within a small section of the central Aleutians is used to examine the general problem of earthquake location in island arcs. Reference hypocenters for this special data set are determined for shallow earthquakes from local-network data and for deep earthquakes from combined local and teleseismic data by joint inversion for structure and location. The high-velocity lithospheric slab beneath the central Aleutians may displace hypocenters that are located using spherically symmetric Earth models; the amount of displacement depends on the position of the earthquakes with respect to the slab and on whether local or teleseismic data are used to locate the earthquakes. Hypocenters for trench and intermediate-depth events appear to be minimally biased by the effects of slab structure on rays to teleseismic stations. However, locations of intermediate-depth events based on only local data are systematically displaced southwards, the magnitude of the displacement being proportional to depth. Shallow-focus events along the main thrust zone, although well located using only local-network data, are severely shifted northwards and deeper, with displacements as large as 50 km, by slab effects on teleseismic travel times. Hypocenters determined by a method that utilizes seismic ray tracing through a three-dimensional velocity model of the subduction zone, derived by thermal modeling, are compared to results obtained by the method of joint hypocenter determination (JHD) that formally assumes a laterally homogeneous velocity model over the source region and treats all raypath anomalies as constant station corrections to the travel-time curve. The ray-tracing method has the theoretical advantage that it accounts for variations in travel-time anomalies within a group of events distributed over a sizable region of a dipping, high

Application of τc*Pd in earthquake early warning

Science.gov (United States)

Huang, Po-Lun; Lin, Ting-Li; Wu, Yih-Min

2015-03-01

Rapid assessment of damage potential and size of an earthquake at the station is highly demanded for onsite earthquake early warning. We study the application of τc*Pd for its estimation on the earthquake size using 123 events recorded by the borehole stations of KiK-net in Japan. The new type of earthquake size determined by τc*Pd is more related to the damage potential. We find that τc*Pd provides another parameter to measure the size of earthquake and the threshold to warn strong ground motion.

Environmental Health assessment 200 Days after Earthquake-Affected Region in East Azerbaijan Earthquake, North-Western of Iran, 2012

Directory of Open Access Journals (Sweden)

Alihossein Zeinalzadeh

2017-04-01

Full Text Available Evaluating of health status and explore the challenges of health problems that threaten human life following disasters and major earthquakes providing windows of opportunities for health care providers in future planning of disasters. The main purpose of this report was to survey the environmental sanitation statues after 200 days of the affected populations in earthquakes of East Azerbaijan, northwestern of Iran, 2012. The survey was carried out in earthquake zones 200 days after the occurrence of the earthquake. A single stage cluster sampling from among 95 villages damaged in the earthquake of 2012 East Azerbaijan of three towns Ahar, Varzeghan and Heris were selected. The data were collected with questionnaire, site visits and evaluation of water and sanitation. In a twin Earthquake, East Azerbaijan province that 399 villages of Ahar, Varzeghan, Heris, Tabriz and Kaleibar cities were affected and 356 (89.2 % villages were destroyed between 30-100%.  Evaluation of water and sanitation infrastructure after 200 days, shown that only half of these villages consumed healthy water with high coverage and adequate. Half of the villages in 200 days after the earthquake were covered safe drinking water (treated drinking water. The bacteriological quality of drinking-water supply of the affected area was assessed in randomly collected 146 samples from this region and ten (6.8% reported as unsuitable. Solid waste management facilities in residents have not been acceptable that affect public health. Solid waste disposal was done by district residents (cooperation rural residents 68.4%, 36.8% and 76.3% in Ahar, Varzeghan and Heris, respectively. Overall, the impact of infectious and communicable diseases after Earthquake was reported 42.1% (16 villages in the Varzeghan. The lack of geographical view with a focus in mountainous and rural areas, partial support and dispersion of earthquake-stricken people in affected villages and lack of participatory need

Leveraging geodetic data to reduce losses from earthquakes

Science.gov (United States)

Murray, Jessica R.; Roeloffs, Evelyn A.; Brooks, Benjamin A.; Langbein, John O.; Leith, William S.; Minson, Sarah E.; Svarc, Jerry L.; Thatcher, Wayne R.

2018-04-23

Seismic hazard assessments that are based on a variety of data and the best available science, coupled with rapid synthesis of real-time information from continuous monitoring networks to guide post-earthquake response, form a solid foundation for effective earthquake loss reduction. With this in mind, the Earthquake Hazards Program (EHP) of the U.S. Geological Survey (USGS) Natural Hazards Mission Area (NHMA) engages in a variety of undertakings, both established and emergent, in order to provide high quality products that enable stakeholders to take action in advance of and in response to earthquakes. Examples include the National Seismic Hazard Model (NSHM), development of tools for improved situational awareness such as earthquake early warning (EEW) and operational earthquake forecasting (OEF), research about induced seismicity, and new efforts to advance comprehensive subduction zone science and monitoring. Geodetic observations provide unique and complementary information directly relevant to advancing many aspects of these efforts (fig. 1). EHP scientists have long leveraged geodetic data for a range of influential studies, and they continue to develop innovative observation and analysis methods that push the boundaries of the field of geodesy as applied to natural hazards research. Given the ongoing, rapid improvement in availability, variety, and precision of geodetic measurements, considering ways to fully utilize this observational resource for earthquake loss reduction is timely and essential. This report presents strategies, and the underlying scientific rationale, by which the EHP could achieve the following outcomes: The EHP is an authoritative source for the interpretation of geodetic data and its use for earthquake loss reduction throughout the United States and its territories.The USGS consistently provides timely, high quality geodetic data to stakeholders.Significant earthquakes are better characterized by incorporating geodetic data into USGS

[Medium- and long-term health effects of the L'Aquila earthquake (Central Italy, 2009) and of other earthquakes in high-income Countries: a systematic review].

Science.gov (United States)

Ripoll Gallardo, Alba; Alesina, Marta; Pacelli, Barbara; Serrone, Dario; Iacutone, Giovanni; Faggiano, Fabrizio; Della Corte, Francesco; Allara, Elias

2016-01-01

to compare the methodological characteristics of the studies investigating the middle- and long-term health effects of the L'Aquila earthquake with the features of studies conducted after other earthquakes occurred in highincome Countries. a systematic comparison between the studies which evaluated the health effects of the L'Aquila earthquake (Central Italy, 6th April 2009) and those conducted after other earthquakes occurred in comparable settings. Medline, Scopus, and 6 sources of grey literature were systematically searched. Inclusion criteria comprised measurement of health outcomes at least one month after the earthquake, investigation of earthquakes occurred in high-income Countries, and presence of at least one temporal or geographical control group. out of 2,976 titles, 13 studies regarding the L'Aquila earthquake and 51 studies concerning other earthquakes were included. The L'Aquila and the Kobe/Hanshin- Awaji (Japan, 17th January 1995) earthquakes were the most investigated. Studies on the L'Aquila earthquake had a median sample size of 1,240 subjects, a median duration of 24 months, and used most frequently a cross sectional design (7/13). Studies on other earthquakes had a median sample size of 320 subjects, a median duration of 15 months, and used most frequently a time series design (19/51). the L'Aquila studies often focussed on mental health, while the earthquake effects on mortality, cardiovascular outcomes, and health systems were less frequently evaluated. A more intensive use of routine data could benefit future epidemiological surveillance in the aftermath of earthquakes.

Time-dependent earthquake probability calculations for southern Kanto after the 2011 M9.0 Tohoku earthquake

Science.gov (United States)

Nanjo, K. Z.; Sakai, S.; Kato, A.; Tsuruoka, H.; Hirata, N.

2013-05-01

Seismicity in southern Kanto activated with the 2011 March 11 Tohoku earthquake of magnitude M9.0, but does this cause a significant difference in the probability of more earthquakes at the present or in the To? future answer this question, we examine the effect of a change in the seismicity rate on the probability of earthquakes. Our data set is from the Japan Meteorological Agency earthquake catalogue, downloaded on 2012 May 30. Our approach is based on time-dependent earthquake probabilistic calculations, often used for aftershock hazard assessment, and are based on two statistical laws: the Gutenberg-Richter (GR) frequency-magnitude law and the Omori-Utsu (OU) aftershock-decay law. We first confirm that the seismicity following a quake of M4 or larger is well modelled by the GR law with b ˜ 1. Then, there is good agreement with the OU law with p ˜ 0.5, which indicates that the slow decay was notably significant. Based on these results, we then calculate the most probable estimates of future M6-7-class events for various periods, all with a starting date of 2012 May 30. The estimates are higher than pre-quake levels if we consider a period of 3-yr duration or shorter. However, for statistics-based forecasting such as this, errors that arise from parameter estimation must be considered. Taking into account the contribution of these errors to the probability calculations, we conclude that any increase in the probability of earthquakes is insignificant. Although we try to avoid overstating the change in probability, our observations combined with results from previous studies support the likelihood that afterslip (fault creep) in southern Kanto will slowly relax a stress step caused by the Tohoku earthquake. This afterslip in turn reminds us of the potential for stress redistribution to the surrounding regions. We note the importance of varying hazards not only in time but also in space to improve the probabilistic seismic hazard assessment for southern Kanto.

Electrostatically actuated resonant switches for earthquake detection

KAUST Repository

Ramini, Abdallah H.

2013-04-01

The modeling and design of electrostatically actuated resonant switches (EARS) for earthquake and seismic applications are presented. The basic concepts are based on operating an electrically actuated resonator close to instability bands of frequency, where it is forced to collapse (pull-in) if operated within these bands. By careful tuning, the resonator can be made to enter the instability zone upon the detection of the earthquake signal, thereby pulling-in as a switch. Such a switching action can be functionalized for useful functionalities, such as shutting off gas pipelines in the case of earthquakes, or can be used to activate a network of sensors for seismic activity recording in health monitoring applications. By placing a resonator on a printed circuit board (PCB) of a natural frequency close to that of the earthquake\\'s frequency, we show significant improvement on the detection limit of the EARS lowering it considerably to less than 60% of the EARS by itself without the PCB. © 2013 IEEE.

Chile Earthquake: U.S. and International Response

Science.gov (United States)

2010-03-11

most regions far from the epicenter did not experience any serious damage. A tsunami caused significant damage to the city of Hilo , Hawaii ...Tsunami Warning Center for Hawaii , Japan, and other regions bordering the Pacific Ocean that may have been vulnerable to a damaging tsunami, although...earthquake. Why the 1960 earthquake generated a tsunami that caused damage and fatalities in Hawaii , Japan, and the Philippines while the 2010 earthquake did

Along-strike variations in fault frictional properties along the San Andreas Fault near Cholame, California from joint earthquake and low-frequency earthquake relocations

Science.gov (United States)

Harrington, Rebecca M.; Cochran, Elizabeth S.; Griffiths, Emily M.; Zeng, Xiangfang; Thurber, Clifford H.

2016-01-01

Recent observations of low‐frequency earthquakes (LFEs) and tectonic tremor along the Parkfield–Cholame segment of the San Andreas fault suggest slow‐slip earthquakes occur in a transition zone between the shallow fault, which accommodates slip by a combination of aseismic creep and earthquakes (fault, which accommodates slip by stable sliding (>35  km depth). However, the spatial relationship between shallow earthquakes and LFEs remains unclear. Here, we present precise relocations of 34 earthquakes and 34 LFEs recorded during a temporary deployment of 13 broadband seismic stations from May 2010 to July 2011. We use the temporary array waveform data, along with data from permanent seismic stations and a new high‐resolution 3D velocity model, to illuminate the fine‐scale details of the seismicity distribution near Cholame and the relation to the distribution of LFEs. The depth of the boundary between earthquakes and LFE hypocenters changes along strike and roughly follows the 350°C isotherm, suggesting frictional behavior may be, in part, thermally controlled. We observe no overlap in the depth of earthquakes and LFEs, with an ∼5  km separation between the deepest earthquakes and shallowest LFEs. In addition, clustering in the relocated seismicity near the 2004 Mw 6.0 Parkfield earthquake hypocenter and near the northern boundary of the 1857 Mw 7.8 Fort Tejon rupture may highlight areas of frictional heterogeneities on the fault where earthquakes tend to nucleate.

Assessment of precast beam-column using capacity demand response spectrum subject to design basis earthquake and maximum considered earthquake

Science.gov (United States)

Ghani, Kay Dora Abd.; Tukiar, Mohd Azuan; Hamid, Nor Hayati Abdul

2017-08-01

Malaysia is surrounded by the tectonic feature of the Sumatera area which consists of two seismically active inter-plate boundaries, namely the Indo-Australian and the Eurasian Plates on the west and the Philippine Plates on the east. Hence, Malaysia experiences tremors from far distant earthquake occurring in Banda Aceh, Nias Island, Padang and other parts of Sumatera Indonesia. In order to predict the safety of precast buildings in Malaysia under near field ground motion the response spectrum analysis could be used for dealing with future earthquake whose specific nature is unknown. This paper aimed to develop of capacity demand response spectrum subject to Design Basis Earthquake (DBE) and Maximum Considered Earthquake (MCE) in order to assess the performance of precast beam column joint. From the capacity-demand response spectrum analysis, it can be concluded that the precast beam-column joints would not survive when subjected to earthquake excitation with surface-wave magnitude, Mw, of more than 5.5 Scale Richter (Type 1 spectra). This means that the beam-column joint which was designed using the current code of practice (BS8110) would be severely damaged when subjected to high earthquake excitation. The capacity-demand response spectrum analysis also shows that the precast beam-column joints in the prototype studied would be severely damaged when subjected to Maximum Considered Earthquake (MCE) with PGA=0.22g having a surface-wave magnitude of more than 5.5 Scale Richter, or Type 1 spectra.

A Comparison of Geodetic and Geologic Rates Prior to Large Strike-Slip Earthquakes: A Diversity of Earthquake-Cycle Behaviors?

Science.gov (United States)

Dolan, James F.; Meade, Brendan J.

2017-12-01

Comparison of preevent geodetic and geologic rates in three large-magnitude (Mw = 7.6-7.9) strike-slip earthquakes reveals a wide range of behaviors. Specifically, geodetic rates of 26-28 mm/yr for the North Anatolian fault along the 1999 MW = 7.6 Izmit rupture are ˜40% faster than Holocene geologic rates. In contrast, geodetic rates of ˜6-8 mm/yr along the Denali fault prior to the 2002 MW = 7.9 Denali earthquake are only approximately half as fast as the latest Pleistocene-Holocene geologic rate of ˜12 mm/yr. In the third example where a sufficiently long pre-earthquake geodetic time series exists, the geodetic and geologic rates along the 2001 MW = 7.8 Kokoxili rupture on the Kunlun fault are approximately equal at ˜11 mm/yr. These results are not readily explicable with extant earthquake-cycle modeling, suggesting that they may instead be due to some combination of regional kinematic fault interactions, temporal variations in the strength of lithospheric-scale shear zones, and/or variations in local relative plate motion rate. Whatever the exact causes of these variable behaviors, these observations indicate that either the ratio of geodetic to geologic rates before an earthquake may not be diagnostic of the time to the next earthquake, as predicted by many rheologically based geodynamic models of earthquake-cycle behavior, or different behaviors characterize different fault systems in a manner that is not yet understood or predictable.

USGS Earthquake Program GPS Use Case : Earthquake Early Warning

Science.gov (United States)

2015-03-12

USGS GPS receiver use case. Item 1 - High Precision User (federal agency with Stafford Act hazard alert responsibilities for earthquakes, volcanoes and landslides nationwide). Item 2 - Description of Associated GPS Application(s): The USGS Eart...

An interdisciplinary approach for earthquake modelling and forecasting

Science.gov (United States)

Han, P.; Zhuang, J.; Hattori, K.; Ogata, Y.

2016-12-01

Earthquake is one of the most serious disasters, which may cause heavy casualties and economic losses. Especially in the past two decades, huge/mega earthquakes have hit many countries. Effective earthquake forecasting (including time, location, and magnitude) becomes extremely important and urgent. To date, various heuristically derived algorithms have been developed for forecasting earthquakes. Generally, they can be classified into two types: catalog-based approaches and non-catalog-based approaches. Thanks to the rapid development of statistical seismology in the past 30 years, now we are able to evaluate the performances of these earthquake forecast approaches quantitatively. Although a certain amount of precursory information is available in both earthquake catalogs and non-catalog observations, the earthquake forecast is still far from satisfactory. In most case, the precursory phenomena were studied individually. An earthquake model that combines self-exciting and mutually exciting elements was developed by Ogata and Utsu from the Hawkes process. The core idea of this combined model is that the status of the event at present is controlled by the event itself (self-exciting) and all the external factors (mutually exciting) in the past. In essence, the conditional intensity function is a time-varying Poisson process with rate λ(t), which is composed of the background rate, the self-exciting term (the information from past seismic events), and the external excitation term (the information from past non-seismic observations). This model shows us a way to integrate the catalog-based forecast and non-catalog-based forecast. Against this background, we are trying to develop a new earthquake forecast model which combines catalog-based and non-catalog-based approaches.

Hotspots, Lifelines, and the Safrr Haywired Earthquake Sequence

Science.gov (United States)

Ratliff, J. L.; Porter, K.

2014-12-01

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.

The 1976 Tangshan earthquake

Science.gov (United States)

Fang, Wang

1979-01-01

The Tangshan earthquake of 1976 was one of the largest earthquakes in recent years. It occurred on July 28 at 3:42 a.m, Beijing (Peking) local time, and had magnitude 7.8, focal depth of 15 kilometers, and an epicentral intensity of XI on the New Chinese Seismic Intensity Scale; it caused serious damage and loss of life in this densely populated industrial city. Now, with the help of people from all over China, the city of Tangshan is being rebuild. 

Earthquake Safety Tips in the Classroom

Science.gov (United States)

Melo, M. O.; Maciel, B. A. P. C.; Neto, R. P.; Hartmann, R. P.; Marques, G.; Gonçalves, M.; Rocha, F. L.; Silveira, G. M.

2014-12-01

The catastrophes induced by earthquakes are among the most devastating ones, causing an elevated number of human losses and economic damages. But, we have to keep in mind that earthquakes don't kill people, buildings do. Earthquakes can't be predicted and the only way of dealing with their effects is to teach the society how to be prepared for them, and how to deal with their consequences. In spite of being exposed to moderate and large earthquakes, most of the Portuguese are little aware of seismic risk, mainly due to the long recurrence intervals between strong events. The acquisition of safe and correct attitudes before, during and after an earthquake is relevant for human security. Children play a determinant role in the establishment of a real and long-lasting "culture of prevention", both through action and new attitudes. On the other hand, when children assume correct behaviors, their relatives often change their incorrect behaviors to mimic the correct behaviors of their kids. In the framework of a Parents-in-Science initiative, we started with bi-monthly sessions for children aged 5 - 6 years old and 9 - 10 years old. These sessions, in which parents, teachers and high-school students participate, became part of the school's permanent activities. We start by a short introduction to the Earth and to earthquakes by story telling and by using simple science activities to trigger children curiosity. With safety purposes, we focus on how crucial it is to know basic information about themselves and to define, with their families, an emergency communications plan, in case family members are separated. Using a shaking table we teach them how to protect themselves during an earthquake. We then finish with the preparation on an individual emergency kit. This presentation will highlight the importance of encouraging preventive actions in order to reduce the impact of earthquakes on society. This project is developed by science high-school students and teachers, in

Shallow moonquakes - How they compare with earthquakes

Science.gov (United States)

Nakamura, Y.

1980-01-01

Of three types of moonquakes strong enough to be detectable at large distances - deep moonquakes, meteoroid impacts and shallow moonquakes - only shallow moonquakes are similar in nature to earthquakes. A comparison of various characteristics of moonquakes with those of earthquakes indeed shows a remarkable similarity between shallow moonquakes and intraplate earthquakes: (1) their occurrences are not controlled by tides; (2) they appear to occur in locations where there is evidence of structural weaknesses; (3) the relative abundances of small and large quakes (b-values) are similar, suggesting similar mechanisms; and (4) even the levels of activity may be close. The shallow moonquakes may be quite comparable in nature to intraplate earthquakes, and they may be of similar origin.

Gas and Dust Phenomena of Mega-earthquakes and the Cause

Science.gov (United States)

Yue, Z.

2013-12-01

A mega-earthquake suddenly releases a large to extremely large amount of kinetic energy within a few tens to two hundreds seconds and over ten to hundreds kilometer distances in the Earth's crust and on ground surface. It also generates seismic waves that can be received globally and co-seismic ground damages such co-seismic ruptures and landslides. However, such vast, dramatic and devastating kinetic actions in the Earth's crustal rocks and on the ground soils cannot be known or predicted by people at few weeks, days, hours, or minutes before they are happening. Although seismologists can develop and use seismometers to report the locations and magnitudes of earthquakes within minutes of their occurrence, they cannot predict earthquakes at present. Therefore, damage earthquakes have caused and would continue to cause huge disasters, fatalities and injuries to our human beings. This problem may indicate that it is necessary to re-examine the cause of mega-earthquakes in addition to the conventional cause of active fault elastic rebounding. In the last ten years, many mega-earthquakes occurred in China and around the Pacific Ocean and caused many casualties to human beings and devastating disasters to environments. The author will give a brief review on the impacts of the mega-earthquakes happened in recent years. He will then present many gas and dust related phenomena associated with the sudden occurrences of these mega earthquakes. They include the 2001 Kunlunshan Earthquake M8.1, 2008 Wenchuan Earthquake M8.0 and the 2010 Yushu Earthquake M7.1 in China, the 2010 Haiti Earthquake M7.0, the 2010 Mexicali Earthquake M7.2, the 2010 Chile Earthquake M8.8, the 2011 Christchurch earthquake M6.3 and the 2011 Japan Earthquake M9.0 around the Pacific Ocean. He will discuss the cause of these gas and dust related phenomena. He will use these phenomena and their common cause to show that the earthquakes were caused the rapid migration and expansion of highly compressed and

Evaluating real-time air-quality data as earthquake indicator

International Nuclear Information System (INIS)

Hsu, Shih-Chieh; Huang, Yi-Tang; Huang, Jr-Chung; Tu, Jien-Yi; Engling, Guenter; Lin, Chuan-Yao; Lin, Fei-Jan; Huang, Chao-Hao

2010-01-01

A catastrophic earthquake, namely the 921-earthquake, occurred with a magnitude of M L = 7.3 in Taiwan on September 21, 1999, causing severe disaster. The evaluation of real-time air-quality data, obtained by the Taiwan Environmental Protection Administration (EPA), revealed a staggering increase in ambient SO 2 concentrations by more than one order of magnitude across the island several hours prior to the earthquake, particularly at background stations. The abrupt increase in SO 2 concentrations likely resulted from seismic-triggered degassing instead of air pollution. An additional case of a large earthquake (M L = 6.8), occurring on March 31, 2002, was examined to confirm our observations of significantly enhanced SO 2 concentrations in ambient air prior to large earthquakes. The coincidence between large earthquakes and increases in trace gases during the pre-quake period (several hours) indicates the potential of employing air-quality monitoring data to forecast catastrophic earthquakes.

Research in historical earthquakes in the Korean peninsula and its circumferential regions

Institute of Scientific and Technical Information of China (English)

翟文杰; 吴戈; 韩绍欣

2004-01-01

@@ The historical earthquake data is one of the important foundations for seismic monitoring, earthquake fore-cast and seismic safety evaluation. However, the recognition of earthquake is limited by the scientific and techno-logical level. Therefore, the earthquake can only be described using perfect earthquake catalogue after the seismo-graph is invented. Before this time, the earthquake parameters were determined according to the earthquake disas-ter on the surface and the written records in history, and the earthquake level was measured using earthquake in-tensity.

Earthquake Risk Mitigation in the Tokyo Metropolitan area

Science.gov (United States)

Hirata, N.; Sakai, S.; Kasahara, K.; Nakagawa, S.; Nanjo, K.; Panayotopoulos, Y.; Tsuruoka, H.

2010-12-01

Seismic disaster risk mitigation in urban areas constitutes a challenge through collaboration of scientific, engineering, and social-science fields. Examples of collaborative efforts include research on detailed plate structure with identification of all significant faults, developing dense seismic networks; strong ground motion prediction, which uses information on near-surface seismic site effects and fault models; earthquake resistant and proof structures; and cross-discipline infrastructure for effective risk mitigation just after catastrophic events. Risk mitigation strategy for the next greater earthquake caused by the Philippine Sea plate (PSP) subducting beneath the Tokyo metropolitan area is of major concern because it caused past mega-thrust earthquakes, such as the 1703 Genroku earthquake (magnitude M8.0) and the 1923 Kanto earthquake (M7.9) which had 105,000 fatalities. A M7 or greater (M7+) earthquake in this area at present has high potential to produce devastating loss of life and property with even greater global economic repercussions. The Central Disaster Management Council of Japan estimates that the M7+ earthquake will cause 11,000 fatalities and 112 trillion yen (about 1 trillion US$) economic loss. This earthquake is evaluated to occur with a probability of 70% in 30 years by the Earthquake Research Committee of Japan. In order to mitigate disaster for greater Tokyo, the Special Project for Earthquake Disaster Mitigation in the Tokyo Metropolitan Area (2007-2011) was launched in collaboration with scientists, engineers, and social-scientists in nationwide institutions. The results that are obtained in the respective fields will be integrated until project termination to improve information on the strategy assessment for seismic risk mitigation in the Tokyo metropolitan area. In this talk, we give an outline of our project as an example of collaborative research on earthquake risk mitigation. Discussion is extended to our effort in progress and

Earthquakes trigger the loss of groundwater biodiversity

Science.gov (United States)

Galassi, Diana M. P.; Lombardo, Paola; Fiasca, Barbara; di Cioccio, Alessia; di Lorenzo, Tiziana; Petitta, Marco; di Carlo, Piero

2014-09-01

Earthquakes are among the most destructive natural events. The 6 April 2009, 6.3-Mw earthquake in L'Aquila (Italy) markedly altered the karstic Gran Sasso Aquifer (GSA) hydrogeology and geochemistry. The GSA groundwater invertebrate community is mainly comprised of small-bodied, colourless, blind microcrustaceans. We compared abiotic and biotic data from two pre-earthquake and one post-earthquake complete but non-contiguous hydrological years to investigate the effects of the 2009 earthquake on the dominant copepod component of the obligate groundwater fauna. Our results suggest that the massive earthquake-induced aquifer strain biotriggered a flushing of groundwater fauna, with a dramatic decrease in subterranean species abundance. Population turnover rates appeared to have crashed, no longer replenishing the long-standing communities from aquifer fractures, and the aquifer became almost totally deprived of animal life. Groundwater communities are notorious for their low resilience. Therefore, any major disturbance that negatively impacts survival or reproduction may lead to local extinction of species, most of them being the only survivors of phylogenetic lineages extinct at the Earth surface. Given the ecological key role played by the subterranean fauna as decomposers of organic matter and ``ecosystem engineers'', we urge more detailed, long-term studies on the effect of major disturbances to groundwater ecosystems.

The Northern Rupture of the 1762 Arakan Meghathrust Earthquake and other Potential Earthquake Sources in Bangladesh.

Science.gov (United States)

Akhter, S. H.; Seeber, L.; Steckler, M. S.

2015-12-01

Bangladesh is one of the most densely populated countries in the world. It occupies a major part of the Bengal Basin, which contains the Ganges-Brahmaputra Delta (GBD), the largest and one of the most active of world deltas, and is located along the Alpine-Himalayan seismic belt. As such it is vulnerable to many natural hazards, especially earthquakes. The country sits at the junction of three tectonic plates - Indian, Eurasian, and the Burma 'sliver' of the Sunda plate. These form two boundaries where plates converge- the India-Eurasia plate boundary to the north forming the Himalaya Arc and the India-Burma plate boundary to the east forming the Indo-Burma Arc. The India-Burma plate boundary is exceptionally wide because collision with the GBD feeds an exception amount of sediment into the subduction zone. Thus the Himalayan continent collision orogeny along with its syntaxes to the N and NE of Bangladesh and the Burma Arc subduction boundary surround Bangladesh on two sides with active faults of regional scale, raising the potential for high-magnitude earthquakes. In recent years Bangladesh has experienced minor to moderate earthquakes. Historical records show that major and great earthquakes have ravaged the country and the neighboring region several times over the last 450 years. Field observations of Tertiary structures along the Chittagong-Teknaf coast reveal that the rupture of 1762 Arakan megathrust earthquake extended as far north as the Sitakund anticline to the north of the city of Chittagong. This earthquake brought changes to the landscape, uplifting the Teknaf peninsula and St. Martin's Island by about 2-2.5 m, and activated two mud volcanos along the axis of the Sitakund anticline, where large tabular blocks of exotic crystalline limestone, were tectonically transported from a deep-seated formation along with the eruptive mud. Vast area of the coast including inland areas east of the lower Meghna River were inundated. More than 500 peoples died near

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

Science.gov (United States)

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

2012-01-01

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

Large earthquake rates from geologic, geodetic, and seismological perspectives

Science.gov (United States)

Jackson, D. D.

2017-12-01

Earthquake rate and recurrence information comes primarily from geology, geodesy, and seismology. Geology gives the longest temporal perspective, but it reveals only surface deformation, relatable to earthquakes only with many assumptions. Geodesy is also limited to surface observations, but it detects evidence of the processes leading to earthquakes, again subject to important assumptions. Seismology reveals actual earthquakes, but its history is too short to capture important properties of very large ones. Unfortunately, the ranges of these observation types barely overlap, so that integrating them into a consistent picture adequate to infer future prospects requires a great deal of trust. Perhaps the most important boundary is the temporal one at the beginning of the instrumental seismic era, about a century ago. We have virtually no seismological or geodetic information on large earthquakes before then, and little geological information after. Virtually all-modern forecasts of large earthquakes assume some form of equivalence between tectonic- and seismic moment rates as functions of location, time, and magnitude threshold. That assumption links geology, geodesy, and seismology, but it invokes a host of other assumptions and incurs very significant uncertainties. Questions include temporal behavior of seismic and tectonic moment rates; shape of the earthquake magnitude distribution; upper magnitude limit; scaling between rupture length, width, and displacement; depth dependence of stress coupling; value of crustal rigidity; and relation between faults at depth and their surface fault traces, to name just a few. In this report I'll estimate the quantitative implications for estimating large earthquake rate. Global studies like the GEAR1 project suggest that surface deformation from geology and geodesy best show the geography of very large, rare earthquakes in the long term, while seismological observations of small earthquakes best forecasts moderate earthquakes

Earthquake Swarm in Armutlu Peninsula, Eastern Marmara Region, Turkey

Science.gov (United States)

Yavuz, Evrim; Çaka, Deniz; Tunç, Berna; Serkan Irmak, T.; Woith, Heiko; Cesca, Simone; Lühr, Birger-Gottfried; Barış, Şerif

2015-04-01

The most active fault system of Turkey is North Anatolian Fault Zone and caused two large earthquakes in 1999. These two earthquakes affected the eastern Marmara region destructively. Unbroken part of the North Anatolian Fault Zone crosses north of Armutlu Peninsula on east-west direction. This branch has been also located quite close to Istanbul known as a megacity with its high population, economic and social aspects. A new cluster of microseismic activity occurred in the direct vicinity southeastern of the Yalova Termal area. Activity started on August 2, 2014 with a series of micro events, and then on August 3, 2014 a local magnitude is 4.1 event occurred, more than 1000 in the followed until August 31, 2014. Thus we call this tentatively a swarm-like activity. Therefore, investigation of the micro-earthquake activity of the Armutlu Peninsula has become important to understand the relationship between the occurrence of micro-earthquakes and the tectonic structure of the region. For these reasons, Armutlu Network (ARNET), installed end of 2005 and equipped with currently 27 active seismic stations operating by Kocaeli University Earth and Space Sciences Research Center (ESSRC) and Helmholtz-Zentrum Potsdam Deutsches GeoForschungsZentrum (GFZ), is a very dense network tool able to record even micro-earthquakes in this region. In the 30 days period of August 02 to 31, 2014 Kandilli Observatory and Earthquake Research Institute (KOERI) announced 120 local earthquakes ranging magnitudes between 0.7 and 4.1, but ARNET provided more than 1000 earthquakes for analyzes at the same time period. In this study, earthquakes of the swarm area and vicinity regions determined by ARNET were investigated. The focal mechanism of the August 03, 2014 22:22:42 (GMT) earthquake with local magnitude (Ml) 4.0 is obtained by the moment tensor solution. According to the solution, it discriminates a normal faulting with dextral component. The obtained focal mechanism solution is

Using remote sensing to predict earthquake impacts

Science.gov (United States)

Fylaktos, Asimakis; Yfantidou, Anastasia

2017-09-01

Natural hazards like earthquakes can result to enormous property damage, and human casualties in mountainous areas. Italy has always been exposed to numerous earthquakes, mostly concentrated in central and southern regions. Last year, two seismic events near Norcia (central Italy) have occurred, which led to substantial loss of life and extensive damage to properties, infrastructure and cultural heritage. This research utilizes remote sensing products and GIS software, to provide a database of information. We used both SAR images of Sentinel 1A and optical imagery of Landsat 8 to examine the differences of topography with the aid of the multi temporal monitoring technique. This technique suits for the observation of any surface deformation. This database is a cluster of information regarding the consequences of the earthquakes in groups, such as property and infrastructure damage, regional rifts, cultivation loss, landslides and surface deformations amongst others, all mapped on GIS software. Relevant organizations can implement these data in order to calculate the financial impact of these types of earthquakes. In the future, we can enrich this database including more regions and enhance the variety of its applications. For instance, we could predict the future impacts of any type of earthquake in several areas, and design a preliminarily model of emergency for immediate evacuation and quick recovery response. It is important to know how the surface moves, in particular geographical regions like Italy, Cyprus and Greece, where earthquakes are so frequent. We are not able to predict earthquakes, but using data from this research, we may assess the damage that could be caused in the future.

The 2007 Mentawai earthquake sequence on the Sumatra megathrust

Science.gov (United States)

Konca, A.; Avouac, J.; Sladen, A.; Meltzner, A. J.; Kositsky, A. P.; Sieh, K.; Fang, P.; Li, Z.; Galetzka, J.; Genrich, J.; Chlieh, M.; Natawidjaja, D. H.; Bock, Y.; Fielding, E. J.; Helmberger, D. V.

2008-12-01

The Sumatra Megathrust has recently produced a flurry of large interplate earthquakes starting with the giant Mw 9.15, Aceh earthquake of 2004. All of these earthquakes occurred within the area monitored by the Sumatra Geodetic Array (SuGAr), which provided exceptional records of near-field co-seismic and postseismic ground displacements. The most recent of these major earthquakes, an Mw 8.4 earthquake and an Mw 7.9 earthquake twelve hours later, occurred in the Mentawai islands area where devastating historical earthquakes had happened in 1797 and 1833. The 2007 earthquake sequence provides an exceptional opportunity to understand the variability of the earthquakes along megathrusts and their relation to interseismic coupling. The InSAR, GPS and teleseismic modeling shows that 2007 earthquakes ruptured a fraction of the strongly coupled Mentawai patch of the megathrust, which is also only a fraction of the 1833 rupture area. It also released a much smaller moment than the one released in 1833, or than the deficit of moment that has accumulated since. Both earthquakes of 2007 consist of 2 sub-events which are 50 to 100 km apart from each other. On the other hand, the northernmost slip patch of 8.4 and southern slip patch of 7.9 earthquakes abut each other, but they ruptured 12 hours apart. Sunda megathrust earthquakes of recent years include a rupture of a strongly coupled patch that closely mimics a prior rupture of that patch and which is well correlated with the interseismic coupling pattern (Nias-Simeulue section), as well as a rupture sequence of a strongly coupled patch that differs substantially in the details from its most recent predecessors (Mentawai section). We conclude that (1) seismic asperities are probably persistent features which arise form heterogeneous strain build up in the interseismic period; and (2) the same portion of a megathrust can rupture in different ways depending on whether asperities break as isolated events or cooperate to produce

Earthquake response observation of isolated buildings

International Nuclear Information System (INIS)

Harada, O.; Kawai, N.; Ishii, T.; Sawada, Y.; Shiojiri, H.; Mazda, T.

1989-01-01

Base isolation system is expected to be a technology for a rational design of FBR plant. In order to apply this system to important structures, accumulation of verification data is necessary. From this point of view, the vibration test and the earthquake response observation of the actual isolated building using laminated rubber bearings and elasto-plastic steel dampers were conducted for the purpose of investigating its dynamic behavior and of proving the reliability of the base isolation system. Since September in 1986, more than thirty earthquakes have been observed. This paper presents the results of the earthquake response observation

Future Developments for the Earthquake Early Warning System following the 2011 off the Pacific Coast of Tohoku Earthquake

Science.gov (United States)

Yamada, M.; Mori, J. J.

2011-12-01

The 2011 off the Pacific Coast of Tohoku Earthquake (Mw9.0) caused significant damage over a large area of northeastern Honshu. An earthquake early warning was issued to the public in the Tohoku region about 8 seconds after the first P-arrival, which is 31 seconds after the origin time. There was no 'blind zone', and warnings were received at all locations before S-wave arrivals, since the earthquake was fairly far offshore. Although the early warning message was properly reported in Tohoku region which was the most severely affected area, a message was not sent to the more distant Tokyo region because the intensity was underestimated. . This underestimation was because the magnitude determination in the first few seconds was relatively small (Mj8.1)., and there was no consideration of a finite fault with a long length. Another significant issue is that warnings were sometimes not properly provided for aftershocks. Immediately following the earthquake, the waveforms of some large aftershocks were contaminated by long-period surface waves from the mainshock, which made it difficult to pick P-wave arrivals. Also, correctly distinguishing and locating later aftershocks was sometimes difficult, when multiple events occurred within a short period of time. This masinhock begins with relatively small moment release for the first 10 s . Since the amplitude of the initial waveforms is small, most methods that use amplitudes and periods of the P-wave (e.g. Wu and Kanamori, 2005) cannot correctly determine the size of the4 earthquake in the first several seconds. The current JMA system uses the peak displacement amplitude for the magnitude estimation, and the magnitude saturated at about M8 1 minute after the first P-wave arrival. . Magnitudes of smaller earthquakes can be correctly identified from the first few seconds of P- or S-wave arrivals, but this M9 event cannot be characterized in such a short time. The only way to correctly characterize the size of the Tohoku

The EM Earthquake Precursor

Science.gov (United States)

Jones, K. B., II; Saxton, P. T.

2013-12-01

Many attempts have been made to determine a sound forecasting method regarding earthquakes and warn the public in turn. Presently, the animal kingdom leads the precursor list alluding to a transmission related source. By applying the animal-based model to an electromagnetic (EM) wave model, various hypotheses were formed, but the most interesting one required the use of a magnetometer with a differing design and geometry. To date, numerous, high-end magnetometers have been in use in close proximity to fault zones for potential earthquake forecasting; however, something is still amiss. The problem still resides with what exactly is forecastable and the investigating direction of EM. After the 1989 Loma Prieta Earthquake, American earthquake investigators predetermined magnetometer use and a minimum earthquake magnitude necessary for EM detection. This action was set in motion, due to the extensive damage incurred and public outrage concerning earthquake forecasting; however, the magnetometers employed, grounded or buried, are completely subject to static and electric fields and have yet to correlate to an identifiable precursor. Secondly, there is neither a networked array for finding any epicentral locations, nor have there been any attempts to find even one. This methodology needs dismissal, because it is overly complicated, subject to continuous change, and provides no response time. As for the minimum magnitude threshold, which was set at M5, this is simply higher than what modern technological advances have gained. Detection can now be achieved at approximately M1, which greatly improves forecasting chances. A propagating precursor has now been detected in both the field and laboratory. Field antenna testing conducted outside the NE Texas town of Timpson in February, 2013, detected three strong EM sources along with numerous weaker signals. The antenna had mobility, and observations were noted for recurrence, duration, and frequency response. Next, two

From Tornadoes to Earthquakes: Forecast Verification for Binary Events Applied to the 1999 Chi-Chi, Taiwan,Earthquake

Directory of Open Access Journals (Sweden)

Chien-Chih Chen

2006-01-01

Full Text Available Forecast verification procedures for statistical events with binary outcomes typically rely on the use of contingency tables and Relative Operating Characteristic (ROC diagrams. Originally developed for the statistical evaluation of tornado forecasts on a county-by-county basis, these methods can be adapted to the evaluation of competing earthquake forecasts. Here we apply these methods retrospectively to two forecasts for the M 7.3 1999 Chi-Chi, Taiwan, earthquake. We show that a previously proposed forecast method that is based on evaluating changes in seismic intensity on a regional basis is superior to a forecast based only on the magnitude of seismic intensity in the same region. Our results confirm earlier suggestions that the earthquake preparation process for events such as the Chi-Chi earthquake involves anomalous activation or quiescence, and that signatures of these processes can be detected in seismicity data using appropriate methods.

Coulomb Failure Stress Accumulation in Nepal After the 2015 Mw 7.8 Gorkha Earthquake: Testing Earthquake Triggering Hypothesis and Evaluating Seismic Hazards

Science.gov (United States)

Xiong, N.; Niu, F.

2017-12-01

A Mw 7.8 earthquake struck Gorkha, Nepal, on April 5, 2015, resulting in more than 8000 deaths and 3.5 million homeless. The earthquake initiated 70km west of Kathmandu and propagated eastward, rupturing an area of approximately 150km by 60km in size. However, the earthquake failed to fully rupture the locked fault beneath the Himalaya, suggesting that the region south of Kathmandu and west of the current rupture are still locked and a much more powerful earthquake might occur in future. Therefore, the seismic hazard of the unruptured region is of great concern. In this study, we investigated the Coulomb failure stress (CFS) accumulation on the unruptured fault transferred by the Gorkha earthquake and some nearby historical great earthquakes. First, we calculated the co-seismic CFS changes of the Gorkha earthquake on the nodal planes of 16 large aftershocks to quantitatively examine whether they were brought closer to failure by the mainshock. It is shown that at least 12 of the 16 aftershocks were encouraged by an increase of CFS of 0.1-3 MPa. The correspondence between the distribution of off-fault aftershocks and the increased CFS pattern also validates the applicability of the earthquake triggering hypothesis in the thrust regime of Nepal. With the validation as confidence, we calculated the co-seismic CFS change on the locked region imparted by the Gorkha earthquake and historical great earthquakes. A newly proposed ramp-flat-ramp-flat fault geometry model was employed, and the source parameters of historical earthquakes were computed with the empirical scaling relationship. A broad region south of the Kathmandu and west of the current rupture were shown to be positively stressed with CFS change roughly ranging between 0.01 and 0.5 MPa. The maximum of CFS increase (>1MPa) was found in the updip segment south of the current rupture, implying a high seismic hazard. Since the locked region may be additionally stressed by the post-seismic relaxation of the lower

Spatial Distribution of earthquakes off the coast of Fukushima Two Years after the M9 Earthquake: the Southern Area of the 2011 Tohoku Earthquake Rupture Zone

Science.gov (United States)

Yamada, T.; Nakahigashi, K.; Shinohara, M.; Mochizuki, K.; Shiobara, H.

2014-12-01

Huge earthquakes cause vastly stress field change around the rupture zones, and many aftershocks and other related geophysical phenomenon such as geodetic movements have been observed. It is important to figure out the time-spacious distribution during the relaxation process for understanding the giant earthquake cycle. In this study, we pick up the southern rupture area of the 2011 Tohoku earthquake (M9.0). The seismicity rate keeps still high compared with that before the 2011 earthquake. Many studies using ocean bottom seismometers (OBSs) have been doing since soon after the 2011 Tohoku earthquake in order to obtain aftershock activity precisely. Here we show one of the studies at off the coast of Fukushima which is located on the southern part of the rupture area caused by the 2011 Tohoku earthquake. We deployed 4 broadband type OBSs (BBOBSs) and 12 short-period type OBSs (SOBS) in August 2012. Other 4 BBOBSs attached with absolute pressure gauges and 20 SOBSs were added in November 2012. We recovered 36 OBSs including 8 BBOBSs in November 2013. We selected 1,000 events in the vicinity of the OBS network based on a hypocenter catalog published by the Japan Meteorological Agency, and extracted the data after time corrections caused by each internal clock. Each P and S wave arrival times, P wave polarity and maximum amplitude were picked manually on a computer display. We assumed one dimensional velocity structure based on the result from an active source experiment across our network, and applied time corrections every station for removing ambiguity of the assumed structure. Then we adopted a maximum-likelihood estimation technique and calculated the hypocenters. The results show that intensive activity near the Japan Trench can be seen, while there was a quiet seismic zone between the trench zone and landward high activity zone.

Extending the ISC-GEM Global Earthquake Instrumental Catalogue

Science.gov (United States)

Di Giacomo, Domenico; Engdhal, Bob; Storchak, Dmitry; Villaseñor, Antonio; Harris, James

2015-04-01

After a 27-month project funded by the GEM Foundation (www.globalquakemodel.org), in January 2013 we released the ISC-GEM Global Instrumental Earthquake Catalogue (1900 2009) (www.isc.ac.uk/iscgem/index.php) as a special product to use for seismic hazard studies. The new catalogue was necessary as improved seismic hazard studies necessitate that earthquake catalogues are homogeneous (to the largest extent possible) over time in their fundamental parameters, such as location and magnitude. Due to time and resource limitation, the ISC-GEM catalogue (1900-2009) included earthquakes selected according to the following time-variable cut-off magnitudes: Ms=7.5 for earthquakes occurring before 1918; Ms=6.25 between 1918 and 1963; and Ms=5.5 from 1964 onwards. Because of the importance of having a reliable seismic input for seismic hazard studies, funding from GEM and two commercial companies in the US and UK allowed us to start working on the extension of the ISC-GEM catalogue both for earthquakes that occurred beyond 2009 and for earthquakes listed in the International Seismological Summary (ISS) which fell below the cut-off magnitude of 6.25. This extension is part of a four-year program that aims at including in the ISC-GEM catalogue large global earthquakes that occurred before the beginning of the ISC Bulletin in 1964. In this contribution we present the updated ISC GEM catalogue, which will include over 1000 more earthquakes that occurred in 2010 2011 and several hundreds more between 1950 and 1959. The catalogue extension between 1935 and 1949 is currently underway. The extension of the ISC-GEM catalogue will also be helpful for regional cross border seismic hazard studies as the ISC-GEM catalogue should be used as basis for cross-checking the consistency in location and magnitude of those earthquakes listed both in the ISC GEM global catalogue and regional catalogues.

Automatic Earthquake Shear Stress Measurement Method Developed for Accurate Time- Prediction Analysis of Forthcoming Major Earthquakes Along Shallow Active Faults

Science.gov (United States)

Serata, S.

2006-12-01

The Serata Stressmeter has been developed to measure and monitor earthquake shear stress build-up along shallow active faults. The development work made in the past 25 years has established the Stressmeter as an automatic stress measurement system to study timing of forthcoming major earthquakes in support of the current earthquake prediction studies based on statistical analysis of seismological observations. In early 1982, a series of major Man-made earthquakes (magnitude 4.5-5.0) suddenly occurred in an area over deep underground potash mine in Saskatchewan, Canada. By measuring underground stress condition of the mine, the direct cause of the earthquake was disclosed. The cause was successfully eliminated by controlling the stress condition of the mine. The Japanese government was interested in this development and the Stressmeter was introduced to the Japanese government research program for earthquake stress studies. In Japan the Stressmeter was first utilized for direct measurement of the intrinsic lateral tectonic stress gradient G. The measurement, conducted at the Mt. Fuji Underground Research Center of the Japanese government, disclosed the constant natural gradients of maximum and minimum lateral stresses in an excellent agreement with the theoretical value, i.e., G = 0.25. All the conventional methods of overcoring, hydrofracturing and deformation, which were introduced to compete with the Serata method, failed demonstrating the fundamental difficulties of the conventional methods. The intrinsic lateral stress gradient determined by the Stressmeter for the Japanese government was found to be the same with all the other measurements made by the Stressmeter in Japan. The stress measurement results obtained by the major international stress measurement work in the Hot Dry Rock Projects conducted in USA, England and Germany are found to be in good agreement with the Stressmeter results obtained in Japan. Based on this broad agreement, a solid geomechanical

Network similarity and statistical analysis of earthquake seismic data

OpenAIRE

Deyasi, Krishanu; Chakraborty, Abhijit; Banerjee, Anirban

2016-01-01

We study the structural similarity of earthquake networks constructed from seismic catalogs of different geographical regions. A hierarchical clustering of underlying undirected earthquake networks is shown using Jensen-Shannon divergence in graph spectra. The directed nature of links indicates that each earthquake network is strongly connected, which motivates us to study the directed version statistically. Our statistical analysis of each earthquake region identifies the hub regions. We cal...

Guidelines for nuclear plant response to an earthquake

International Nuclear Information System (INIS)

1989-12-01

Guidelines have been developed to assist nuclear plant personnel in the preparation of earthquake response procedures for nuclear power plants. The objectives of the earthquake response procedures are to determine (1) the immediate effects of an earthquake on the physical condition of the nuclear power plant, (2) if shutdown of the plant is appropriate based on the observed damage to the plant or because the OBE has been exceeded, and (3) the readiness of the plant to resume operation following shutdown due to an earthquake. Readiness of a nuclear power plant to restart is determined on the basis of visual inspections of nuclear plant equipment and structures, and the successful completion of surveillance tests which demonstrate that the limiting conditions for operation as defined in the plant Technical Specifications are met. The guidelines are based on information obtained from a review of earthquake response procedures from numerous US and foreign nuclear power plants, interviews with nuclear plant operations personnel, and a review of reports of damage to industrial equipment and structures in actual earthquakes. 7 refs., 4 figs., 4 tabs

High resolution measurement of earthquake impacts on rock slope stability and damage using pre- and post-earthquake terrestrial laser scans

Science.gov (United States)

Hutchinson, Lauren; Stead, Doug; Rosser, Nick

2017-04-01

Understanding the behaviour of rock slopes in response to earthquake shaking is instrumental in response and relief efforts following large earthquakes as well as to ongoing risk management in earthquake affected areas. Assessment of the effects of seismic shaking on rock slope kinematics requires detailed surveys of the pre- and post-earthquake condition of the slope; however, at present, there is a lack of high resolution monitoring data from pre- and post-earthquake to facilitate characterization of seismically induced slope damage and validate models used to back-analyze rock slope behaviour during and following earthquake shaking. Therefore, there is a need for additional research where pre- and post- earthquake monitoring data is available. This paper presents the results of a direct comparison between terrestrial laser scans (TLS) collected in 2014, the year prior to the 2015 earthquake sequence, with that collected 18 months after the earthquakes and two monsoon cycles. The two datasets were collected using Riegl VZ-1000 and VZ-4000 full waveform laser scanners with high resolution (c. 0.1 m point spacing as a minimum). The scans cover the full landslide affected slope from the toe to the crest. The slope is located in Sindhupalchok District, Central Nepal which experienced some of the highest co-seismic and post-seismic landslide intensities across Nepal due to the proximity to the epicenters (<20 km) of both of the main aftershocks on April 26, 2015 (M 6.7) and May 12, 2015 (M7.3). During the 2015 earthquakes and subsequent 2015 and 2016 monsoons, the slope experienced rockfall and debris flows which are evident in satellite imagery and field photographs. Fracturing of the rock mass associated with the seismic shaking is also evident at scales not accessible through satellite and field observations. The results of change detection between the TLS datasets with an emphasis on quantification of seismically-induced slope damage is presented. Patterns in the

Strong ground motion prediction using virtual earthquakes.

Science.gov (United States)

Denolle, M A; Dunham, E M; Prieto, G A; Beroza, G C

2014-01-24

Sedimentary basins increase the damaging effects of earthquakes by trapping and amplifying seismic waves. Simulations of seismic wave propagation in sedimentary basins capture this effect; however, there exists no method to validate these results for earthquakes that have not yet occurred. We present a new approach for ground motion prediction that uses the ambient seismic field. We apply our method to a suite of magnitude 7 scenario earthquakes on the southern San Andreas fault and compare our ground motion predictions with simulations. Both methods find strong amplification and coupling of source and structure effects, but they predict substantially different shaking patterns across the Los Angeles Basin. The virtual earthquake approach provides a new approach for predicting long-period strong ground motion.

Earthquake Damping Device for Steel Frame

Science.gov (United States)

Zamri Ramli, Mohd; Delfy, Dezoura; Adnan, Azlan; Torman, Zaida

2018-04-01

Structures such as buildings, bridges and towers are prone to collapse when natural phenomena like earthquake occurred. Therefore, many design codes are reviewed and new technologies are introduced to resist earthquake energy especially on building to avoid collapse. The tuned mass damper is one of the earthquake reduction products introduced on structures to minimise the earthquake effect. This study aims to analyse the effectiveness of tuned mass damper by experimental works and finite element modelling. The comparisons are made between these two models under harmonic excitation. Based on the result, it is proven that installing tuned mass damper will reduce the dynamic response of the frame but only in several input frequencies. At the highest input frequency applied, the tuned mass damper failed to reduce the responses. In conclusion, in order to use a proper design of damper, detailed analysis must be carried out to have sufficient design based on the location of the structures with specific ground accelerations.

Fault failure with moderate earthquakes

Science.gov (United States)

Johnston, M. J. S.; Linde, A. T.; Gladwin, M. T.; Borcherdt, R. D.

1987-12-01

High resolution strain and tilt recordings were made in the near-field of, and prior to, the May 1983 Coalinga earthquake ( ML = 6.7, Δ = 51 km), the August 4, 1985, Kettleman Hills earthquake ( ML = 5.5, Δ = 34 km), the April 1984 Morgan Hill earthquake ( ML = 6.1, Δ = 55 km), the November 1984 Round Valley earthquake ( ML = 5.8, Δ = 54 km), the January 14, 1978, Izu, Japan earthquake ( ML = 7.0, Δ = 28 km), and several other smaller magnitude earthquakes. These recordings were made with near-surface instruments (resolution 10 -8), with borehole dilatometers (resolution 10 -10) and a 3-component borehole strainmeter (resolution 10 -9). While observed coseismic offsets are generally in good agreement with expectations from elastic dislocation theory, and while post-seismic deformation continued, in some cases, with a moment comparable to that of the main shock, preseismic strain or tilt perturbations from hours to seconds (or less) before the main shock are not apparent above the present resolution. Precursory slip for these events, if any occurred, must have had a moment less than a few percent of that of the main event. To the extent that these records reflect general fault behavior, the strong constraint on the size and amount of slip triggering major rupture makes prediction of the onset times and final magnitudes of the rupture zones a difficult task unless the instruments are fortuitously installed near the rupture initiation point. These data are best explained by an inhomogeneous failure model for which various areas of the fault plane have either different stress-slip constitutive laws or spatially varying constitutive parameters. Other work on seismic waveform analysis and synthetic waveforms indicates that the rupturing process is inhomogeneous and controlled by points of higher strength. These models indicate that rupture initiation occurs at smaller regions of higher strength which, when broken, allow runaway catastrophic failure.

GIS BASED SYSTEM FOR POST-EARTHQUAKE CRISIS MANAGMENT USING CELLULAR NETWORK

OpenAIRE

Raeesi, M.; Sadeghi-Niaraki, A.

2013-01-01

Earthquakes are among the most destructive natural disasters. Earthquakes happen mainly near the edges of tectonic plates, but they may happen just about anywhere. Earthquakes cannot be predicted. Quick response after disasters, like earthquake, decreases loss of life and costs. Massive earthquakes often cause structures to collapse, trapping victims under dense rubble for long periods of time. After the earthquake and destroyed some areas, several teams are sent to find the location of the d...

Understanding Great Earthquakes in Japan's Kanto Region

Science.gov (United States)

Kobayashi, Reiji; Curewitz, Daniel

2008-10-01

Third International Workshop on the Kanto Asperity Project; Chiba, Japan, 16-19 February 2008; The 1703 (Genroku) and 1923 (Taisho) earthquakes in Japan's Kanto region (M 8.2 and M 7.9, respectively) caused severe damage in the Tokyo metropolitan area. These great earthquakes occurred along the Sagami Trough, where the Philippine Sea slab is subducting beneath Japan. Historical records, paleoseismological research, and geophysical/geodetic monitoring in the region indicate that such great earthquakes will repeat in the future.

Magnitudes and frequencies of earthquakes in relation to seismic risk

International Nuclear Information System (INIS)

Sharma, R.D.

1989-01-01

Estimating the frequencies of occurrence of earthquakes of different magnitudes on a regional basis is an important task in estimating seismic risk at a construction site. Analysis of global earthquake data provides an insight into the magnitudes frequency relationship in a statistical manner. It turns out that, whereas a linear relationship between the logarithm of earthquake occurrence rates and the corresponding earthquake magnitudes fits well in the magnitude range between 5 and 7, a second degree polynomial in M, the earthquake magnitude provides a better description of the frequencies of earthquakes in a much wider range of magnitudes. It may be possible to adopt magnitude frequency relation for regions, for which adequate earthquake data are not available, to carry out seismic risk calculations. (author). 32 refs., 8 tabs., 7 figs

The 1985 México earthquake The 1985 México earthquake

Directory of Open Access Journals (Sweden)

Moreno Murillo Juan Manuel

1995-10-01

Full Text Available

This paper includes a bibliographic review with the description of the various aspects about the (Ms = 8.1 Michoacan, Mexico earthquake, which comprised of three events. The main shock of the September 19, 1985 earthquake occurred on Thursday at 7h. 17m. 46.6s. local time in Mexico City, and had (Ms = 8.1. The focus of the event was a depth of approximately 18 km. A second shock occurred on Friday evening 21 September at 7h. 38m. p.m. local time. The last aftershock occurred on 30 April of 1986 (Ms = 7.0. A prior event occurred to the September 1985 earthquake, occurred on 28 May, 1985 (mb = 5.2 and is described too. This event, was a terrible natural disaster for that country, at least 9,500 people were killed, about 30,000 were injured, more that 100,000 were left homeless and severe damage occurred in many parts of Mexico City and several states of central Mexico. According to some sources, It is estimated that the earthquake seriously affected an area of approximately 825,000 square kilometers. This paper describes a summary of the global tectonic setting, genesis and location of the epicenter, an interpretation of the source mechanism and a analyses at these results from some stations that recorded this earthquake and at the same time, a comparison between the two largest earthquake of 1985. Moreover, this paper describes the principal damage resulting and a description of effects from tsunami produced from earthquake. The 1985 Mexico earthquake occurred as a result of slipping in the subduction process between the Cocos and American plates. This was a shallow interplate thrust type event which occurred in the intersection of the Orozco fracture with the Middle American trench.

Global variations of large megathrust earthquake rupture characteristics

Science.gov (United States)

Kanamori, Hiroo

2018-01-01

Despite the surge of great earthquakes along subduction zones over the last decade and advances in observations and analysis techniques, it remains unclear whether earthquake complexity is primarily controlled by persistent fault properties or by dynamics of the failure process. We introduce the radiated energy enhancement factor (REEF), given by the ratio of an event’s directly measured radiated energy to the calculated minimum radiated energy for a source with the same seismic moment and duration, to quantify the rupture complexity. The REEF measurements for 119 large [moment magnitude (Mw) 7.0 to 9.2] megathrust earthquakes distributed globally show marked systematic regional patterns, suggesting that the rupture complexity is strongly influenced by persistent geological factors. We characterize this as the existence of smooth and rough rupture patches with varying interpatch separation, along with failure dynamics producing triggering interactions that augment the regional influences on large events. We present an improved asperity scenario incorporating both effects and categorize global subduction zones and great earthquakes based on their REEF values and slip patterns. Giant earthquakes rupturing over several hundred kilometers can occur in regions with low-REEF patches and small interpatch spacing, such as for the 1960 Chile, 1964 Alaska, and 2011 Tohoku earthquakes, or in regions with high-REEF patches and large interpatch spacing as in the case for the 2004 Sumatra and 1906 Ecuador-Colombia earthquakes. Thus, combining seismic magnitude Mw and REEF, we provide a quantitative framework to better represent the span of rupture characteristics of great earthquakes and to understand global seismicity. PMID:29750186

Is earthquake rate in south Iceland modified by seasonal loading?