78 FR 8109 - Advisory Committee on Earthquake Hazards Reduction Meeting

Federal Register 2010, 2011, 2012, 2013, 2014

2013-02-05

... Earthquake Hazards Reduction Meeting AGENCY: National Institute of Standards and Technology, Department of Commerce. ACTION: Notice of open meeting. SUMMARY: The Advisory Committee on Earthquake Hazards Reduction... meeting on the National Earthquake Hazards Reduction Program (NEHRP) web site at http://nehrp.gov...

77 FR 75610 - Advisory Committee on Earthquake Hazards Reduction Meeting

Federal Register 2010, 2011, 2012, 2013, 2014

2012-12-21

... Earthquake Hazards Reduction Meeting AGENCY: National Institute of Standards and Technology, Department of Commerce. ACTION: Notice of open meeting. SUMMARY: The Advisory Committee on Earthquake Hazards Reduction... meeting on the National Earthquake Hazards Reduction Program (NEHRP) Web site at http://nehrp.gov...

Understanding earthquake hazards in urban areas - Evansville Area Earthquake Hazards Mapping Project

USGS Publications Warehouse

Boyd, Oliver S.

2012-01-01

The region surrounding Evansville, Indiana, has experienced minor damage from earthquakes several times in the past 200 years. Because of this history and the proximity of Evansville to the Wabash Valley and New Madrid seismic zones, there is concern among nearby communities about hazards from earthquakes. Earthquakes currently cannot be predicted, but scientists can estimate how strongly the ground is likely to shake as a result of an earthquake and are able to design structures to withstand this estimated ground shaking. Earthquake-hazard maps provide one way of conveying such information and can help the region of Evansville prepare for future earthquakes and reduce earthquake-caused loss of life and financial and structural loss. The Evansville Area Earthquake Hazards Mapping Project (EAEHMP) has produced three types of hazard maps for the Evansville area: (1) probabilistic seismic-hazard maps show the ground motion that is expected to be exceeded with a given probability within a given period of time; (2) scenario ground-shaking maps show the expected shaking from two specific scenario earthquakes; (3) liquefaction-potential maps show how likely the strong ground shaking from the scenario earthquakes is to produce liquefaction. These maps complement the U.S. Geological Survey's National Seismic Hazard Maps but are more detailed regionally and take into account surficial geology, soil thickness, and soil stiffness; these elements greatly affect ground shaking.

Lateral spread hazard mapping of the northern Salt Lake Valley, Utah, for a M7.0 scenario earthquake

USGS Publications Warehouse

Olsen, M.J.; Bartlett, S.F.; Solomon, B.J.

2007-01-01

This paper describes the methodology used to develop a lateral spread-displacement hazard map for northern Salt Lake Valley, Utah, using a scenario M7.0 earthquake occurring on the Salt Lake City segment of the Wasatch fault. The mapping effort is supported by a substantial amount of geotechnical, geologic, and topographic data compiled for the Salt Lake Valley, Utah. ArcGIS?? routines created for the mapping project then input this information to perform site-specific lateral spread analyses using methods developed by Bartlett and Youd (1992) and Youd et al. (2002) at individual borehole locations. The distributions of predicted lateral spread displacements from the boreholes located spatially within a geologic unit were subsequently used to map the hazard for that particular unit. The mapped displacement zones consist of low hazard (0-0.1 m), moderate hazard (0.1-0.3 m), high hazard (0.3-1.0 m), and very high hazard (> 1.0 m). As expected, the produced map shows the highest hazard in the alluvial deposits at the center of the valley and in sandy deposits close to the fault. This mapping effort is currently being applied to the southern part of the Salt Lake Valley, Utah, and probabilistic maps are being developed for the entire valley. ?? 2007, Earthquake Engineering Research Institute.

Increased Earthquake Rates in the Central and Eastern US Portend Higher Earthquake Hazards

NASA Astrophysics Data System (ADS)

Llenos, A. L.; Rubinstein, J. L.; Ellsworth, W. L.; Mueller, C. S.; Michael, A. J.; McGarr, A.; Petersen, M. D.; Weingarten, M.; Holland, A. A.

2014-12-01

Since 2009 the central and eastern United States has experienced an unprecedented increase in the rate of M≥3 earthquakes that is unlikely to be due to natural variation. Where the rates have increased so has the seismic hazard, making it important to understand these changes. Areas with significant seismicity increases are limited to areas where oil and gas production take place. By far the largest contributor to the seismicity increase is Oklahoma, where recent studies suggest that these rate changes may be due to fluid injection (e.g., Keranen et al., Geology, 2013; Science, 2014). Moreover, the area of increased seismicity in northern Oklahoma that began in 2013 coincides with the Mississippi Lime play, where well completions greatly increased the year before the seismicity increase. This suggests a link to oil and gas production either directly or from the disposal of significant amounts of produced water within the play. For the purpose of assessing the hazard due to these earthquakes, should they be treated differently from natural earthquakes? Previous studies suggest that induced seismicity may differ from natural seismicity in clustering characteristics or frequency-magnitude distributions (e.g., Bachmann et al., GJI, 2011; Llenos and Michael, BSSA, 2013). These differences could affect time-independent hazard computations, which typically assume that clustering and size distribution remain constant. In Oklahoma, as well as other areas of suspected induced seismicity, we find that earthquakes since 2009 tend to be considerably more clustered in space and time than before 2009. However differences between various regional and national catalogs leave unclear whether there are significant changes in magnitude distribution. Whether they are due to natural or industrial causes, the increased earthquake rates in these areas could increase the hazard in ways that are not accounted for in current hazard assessment practice. Clearly the possibility of induced

Applications of research from the U.S. Geological Survey program, assessment of regional earthquake hazards and risk along the Wasatch Front, Utah

USGS Publications Warehouse

Gori, Paula L.

1993-01-01

INTERACTIVE WORKSHOPS: ESSENTIAL ELEMENTS OF THE EARTHQUAKE HAZARDS RESEARCH AND REDUCTION PROGRAM IN THE WASATCH FRONT, UTAH: Interactive workshops provided the forum and stimulus necessary to foster collaboration among the participants in the multidisciplinary, 5-yr program of earthquake hazards reduction in the Wasatch Front, Utah. The workshop process validated well-documented social science theories on the importance of interpersonal interaction, including interaction between researchers and users of research to increase the probability that research will be relevant to the user's needs and, therefore, more readily used. REDUCING EARTHQUAKE HAZARDS IN UTAH: THE CRUCIAL CONNECTION BETWEEN RESEARCHERS AND PRACTITIONERS: Complex scientific and engineering studies must be translated for and transferred to nontechnical personnel for use in reducing earthquake hazards in Utah. The three elements needed for effective translation, likelihood of occurrence, location, and severity of potential hazards, and the three elements needed for effective transfer, delivery, assistance, and encouragement, are described and illustrated for Utah. The importance of evaluating and revising earthquake hazard reduction programs and their components is emphasized. More than 30 evaluations of various natural hazard reduction programs and techniques are introduced. This report was prepared for research managers, funding sources, and evaluators of the Utah earthquake hazard reduction program who are concerned about effectiveness. An overview of the Utah program is provided for those researchers, engineers, planners, and decisionmakers, both public and private, who are committed to reducing human casualties, property damage, and interruptions of socioeconomic systems. PUBLIC PERCEPTIONS OF THE IMPLEMENTATION OF EARTHQUAKE MITIGATION POLICIES ALONG THE WASATCH FRONT IN UTAH: The earthquake hazard potential along the Wasatch Front in Utah has been well defined by a number of scientific and

Seismicity and seismic hazard in Sabah, East Malaysia from earthquake and geodetic data

NASA Astrophysics Data System (ADS)

Gilligan, A.; Rawlinson, N.; Tongkul, F.; Stephenson, R.

2017-12-01

While the levels of seismicity are low in most of Malaysia, the state of Sabah in northern Borneo has moderate levels of seismicity. Notable earthquakes in the region include the 1976 M6.2 Lahad Datu earthquake and the 2015 M6 Ranau earthquake. The recent Ranau earthquake resulted in the deaths of 18 people on Mt Kinabalu, an estimated 100 million RM ( US$23 million) damage to buildings, roads, and infrastructure from shaking, and flooding, reduced water quality, and damage to farms from landslides. Over the last 40 years the population of Sabah has increased to over four times what it was in 1976, yet seismic hazard in Sabah remains poorly understood. Using seismic and geodetic data we hope to better quantify the hazards posed by earthquakes in Sabah, and thus help to minimize risk. In order to do this we need to know about the locations of earthquakes, types of earthquakes that occur, and faults that are generating them. We use data from 15 MetMalaysia seismic stations currently operating in Sabah to develop a region-specific velocity model from receiver functions and a pre-existing surface wave model. We use this new velocity model to (re)locate earthquakes that occurred in Sabah from 2005-2016, including a large number of aftershocks from the 2015 Ranau earthquake. We use a probabilistic nonlinear earthquake location program to locate the earthquakes and then refine their relative locations using a double difference method. The recorded waveforms are further used to obtain moment tensor solutions for these earthquakes. Earthquake locations and moment tensor solutions are then compared with the locations of faults throughout Sabah. Faults are identified from high-resolution IFSAR images and subsequent fieldwork, with a particular focus on the Lahad Datau and Ranau areas. Used together, these seismic and geodetic data can help us to develop a new seismic hazard model for Sabah, as well as aiding in the delivery of outreach activities regarding seismic hazard

The HayWired Earthquake Scenario—Earthquake Hazards

USGS Publications Warehouse

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

Seismic Hazard Assessment for a Characteristic Earthquake Scenario: Probabilistic-Deterministic Method

NASA Astrophysics Data System (ADS)

mouloud, Hamidatou

2016-04-01

The objective of this paper is to analyze the seismic activity and the statistical treatment of seismicity catalog the Constantine region between 1357 and 2014 with 7007 seismic event. Our research is a contribution to improving the seismic risk management by evaluating the seismic hazard in the North-East Algeria. In the present study, Earthquake hazard maps for the Constantine region are calculated. Probabilistic seismic hazard analysis (PSHA) is classically performed through the Cornell approach by using a uniform earthquake distribution over the source area and a given magnitude range. This study aims at extending the PSHA approach to the case of a characteristic earthquake scenario associated with an active fault. The approach integrates PSHA with a high-frequency deterministic technique for the prediction of peak and spectral ground motion parameters in a characteristic earthquake. The method is based on the site-dependent evaluation of the probability of exceedance for the chosen strong-motion parameter. We proposed five sismotectonique zones. Four steps are necessary: (i) identification of potential sources of future earthquakes, (ii) assessment of their geological, geophysical and geometric, (iii) identification of the attenuation pattern of seismic motion, (iv) calculation of the hazard at a site and finally (v) hazard mapping for a region. In this study, the procedure of the earthquake hazard evaluation recently developed by Kijko and Sellevoll (1992) is used to estimate seismic hazard parameters in the northern part of Algeria.

Earthquake risk reduction in the United States: An assessment of selected user needs and recommendations for the National Earthquake Hazards Reduction Program

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

1994-12-31

This Assessment was conducted to improve the National Earthquake Hazards Reduction Program (NEHRP) by providing NEHRP agencies with information that supports their user-oriented setting of crosscutting priorities in the NEHRP strategic planning process. The primary objective of this Assessment was to take a ``snapshot`` evaluation of the needs of selected users throughout the major program elements of NEHRP. Secondary objectives were to conduct an assessment of the knowledge that exists (or is being developed by NEHRP) to support earthquake risk reduction, and to begin a process of evaluating how NEHRP is meeting user needs. An identification of NEHRP`s strengths alsomore » resulted from the effort, since those strengths demonstrate successful methods that may be useful to NEHRP in the future. These strengths are identified in the text, and many of them represent important achievements since the Earthquake Hazards Reduction Act was passed in 1977.« less

Assessing the Utility of and Improving USGS Earthquake Hazards Program Products

NASA Astrophysics Data System (ADS)

Gomberg, J. S.; Scott, M.; Weaver, C. S.; Sherrod, B. L.; Bailey, D.; Gibbons, D.

2010-12-01

A major focus of the USGS Earthquake Hazards Program (EHP) has been the development and implementation of products and information meant to improve earthquake hazard assessment, mitigation and response for a myriad of users. Many of these products rely on the data and efforts of the EHP and its partner scientists who are building the Advanced National Seismic System (ANSS). We report on a project meant to assess the utility of many of these products and information, conducted collaboratively by EHP scientists and Pierce County Department of Emergency Management staff. We have conducted focus group listening sessions with members of the engineering, business, medical, media, risk management, and emergency response communities as well as participated in the planning and implementation of earthquake exercises in the Pacific Northwest. Thus far we have learned that EHP and ANSS products satisfy many of the needs of engineers and some planners, and information is widely used by media and the general public. However, some important communities do not use these products despite their intended application for their purposes, particularly county and local emergency management and business communities. We have learned that products need to convey more clearly the impact of earthquakes, in everyday terms. Users also want products (e.g. maps, forecasts, etc.) that can be incorporated into tools and systems they use regularly. Rather than simply building products and posting them on websites, products need to be actively marketed and training provided. We suggest that engaging users prior to and during product development will enhance their usage and effectiveness.

Probabilistic earthquake hazard analysis for Cairo, Egypt

NASA Astrophysics Data System (ADS)

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

2016-04-01

Cairo is the capital of Egypt and the largest city in the Arab world and Africa, and the sixteenth largest metropolitan area in the world. It was founded in the tenth century (969 ad) and is 1046 years old. It has long been a center of the region's political and cultural life. Therefore, the earthquake risk assessment for Cairo has a great importance. The present work aims to analysis the earthquake hazard of Cairo as a key input's element for the risk assessment. The regional seismotectonics setting shows that Cairo could be affected by both far- and near-field seismic sources. The seismic hazard of Cairo has been estimated using the probabilistic seismic hazard approach. The logic tree frame work was used during the calculations. Epistemic uncertainties were considered into account by using alternative seismotectonics models and alternative ground motion prediction equations. Seismic hazard values have been estimated within a grid of 0.1° × 0.1 ° spacing for all of Cairo's districts at different spectral periods and four return periods (224, 615, 1230, and 4745 years). Moreover, the uniform hazard spectra have been calculated at the same return periods. The pattern of the contour maps show that the highest values of the peak ground acceleration is concentrated in the eastern zone's districts (e.g., El Nozha) and the lowest values at the northern and western zone's districts (e.g., El Sharabiya and El Khalifa).

Earthquake Hazard Analysis Methods: A Review

NASA Astrophysics Data System (ADS)

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.

Earthquakes Magnitude Predication Using Artificial Neural Network in Northern Red Sea Area

NASA Astrophysics Data System (ADS)

Alarifi, A. S.; Alarifi, N. S.

2009-12-01

Earthquakes are natural hazards that do not happen very often, however they may cause huge losses in life and property. Early preparation for these hazards is a key factor to reduce their damage and consequence. Since early ages, people tried to predicate earthquakes using simple observations such as strange or a typical animal behavior. In this paper, we study data collected from existing earthquake catalogue to give better forecasting for future earthquakes. The 16000 events cover a time span of 1970 to 2009, the magnitude range from greater than 0 to less than 7.2 while the depth range from greater than 0 to less than 100km. We propose a new artificial intelligent predication system based on artificial neural network, which can be used to predicate the magnitude of future earthquakes in northern Red Sea area including the Sinai Peninsula, the Gulf of Aqaba, and the Gulf of Suez. We propose a feed forward new neural network model with multi-hidden layers to predicate earthquakes occurrences and magnitudes in northern Red Sea area. Although there are similar model that have been published before in different areas, to our best knowledge this is the first neural network model to predicate earthquake in northern Red Sea area. Furthermore, we present other forecasting methods such as moving average over different interval, normally distributed random predicator, and uniformly distributed random predicator. In addition, we present different statistical methods and data fitting such as linear, quadratic, and cubic regression. We present a details performance analyses of the proposed methods for different evaluation metrics. The results show that neural network model provides higher forecast accuracy than other proposed methods. The results show that neural network achieves an average absolute error of 2.6% while an average absolute error of 3.8%, 7.3% and 6.17% for moving average, linear regression and cubic regression, respectively. In this work, we show an analysis

Multiple Landslide-Hazard Scenarios Modeled for the Oakland-Berkeley Area, Northern California

USGS Publications Warehouse

Pike, Richard J.; Graymer, Russell W.

2008-01-01

With the exception of Los Angeles, perhaps no urban area in the United States is more at risk from landsliding, triggered by either precipitation or earthquake, than the San Francisco Bay region of northern California. By January each year, seasonal winter storms usually bring moisture levels of San Francisco Bay region hillsides to the point of saturation, after which additional heavy rainfall may induce landslides of various types and levels of severity. In addition, movement at any time along one of several active faults in the area may generate an earthquake large enough to trigger landslides. The danger to life and property rises each year as local populations continue to expand and more hillsides are graded for development of residential housing and its supporting infrastructure. The chapters in the text consist of: *Introduction by Russell W. Graymer *Chapter 1 Rainfall Thresholds for Landslide Activity, San Francisco Bay Region, Northern California by Raymond C. Wilson *Chapter 2 Susceptibility to Deep-Seated Landsliding Modeled for the Oakland-Berkeley Area, Northern California by Richard J. Pike and Steven Sobieszczyk *Chapter 3 Susceptibility to Shallow Landsliding Modeled for the Oakland-Berkeley Area, Northern California by Kevin M. Schmidt and Steven Sobieszczyk *Chapter 4 Landslide Hazard Modeled for the Cities of Oakland, Piedmont, and Berkeley, Northern California, from a M=7.1 Scenario Earthquake on the Hayward Fault Zone by Scott B. Miles and David K. Keefer *Chapter 5 Synthesis of Landslide-Hazard Scenarios Modeled for the Oakland-Berkeley Area, Northern California by Richard J. Pike The plates consist of: *Plate 1 Susceptibility to Deep-Seated Landsliding Modeled for the Oakland-Berkeley Area, Northern California by Richard J. Pike, Russell W. Graymer, Sebastian Roberts, Naomi B. Kalman, and Steven Sobieszczyk *Plate 2 Susceptibility to Shallow Landsliding Modeled for the Oakland-Berkeley Area, Northern California by Kevin M. Schmidt and Steven

USGS Training in Afghanistan: Modern Earthquake Hazards Assessments

NASA Astrophysics Data System (ADS)

Medlin, J. D.; Garthwaite, M.; Holzer, T.; McGarr, A.; Bohannon, R.; Bergen, K.; Vincent, T.

2007-05-01

Afghanistan is located in a tectonically active region where ongoing deformation has generated rugged mountainous terrain, and where large earthquakes occur frequently. These earthquakes can present a significant hazard, not only from strong ground shaking, but also from liquefaction and extensive land sliding. The magnitude 6.1 earthquake of March 25, 2002 highlighted the vulnerability of Afghanistan to such hazards, and resulted in over 1000 fatalities. The USGS has provided the first of a series of Earth Science training courses to the Afghan Geological Survey (AGS). This course was concerned with modern earthquake hazard assessments, and is an integral part of a larger USGS effort to provide a comprehensive seismic-hazard assessment for Afghanistan. Funding for these courses is provided by the US Agency for International Development Afghanistan Reconstruction Program. The particular focus of this training course, held December 2-6, 2006 in Kabul, was on providing a background in the seismological and geological methods relevant to preparing for future earthquakes. Topics included identifying active faults, modern tectonic theory, geotechnical measurements of near-surface materials, and strong-motion seismology. With this background, participants may now be expected to educate other members of the community and be actively involved in earthquake hazard assessments themselves. The December, 2006, training course was taught by four lecturers, with all lectures and slides being presented in English and translated into Dari. Copies of the lectures were provided to the students in both hardcopy and digital formats. Class participants included many of the section leaders from within the AGS who have backgrounds in geology, geophysics, and engineering. Two additional training sessions are planned for 2007, the first entitled "Modern Concepts in Geology and Mineral Resource Assessments," and the second entitled "Applied Geophysics for Mineral Resource Assessments."

Understanding and responding to earthquake hazards

NASA Technical Reports Server (NTRS)

Raymond, C. A.; Lundgren, P. R.; Madsen, S. N.; Rundle, J. B.

2002-01-01

Advances in understanding of the earthquake cycle and in assessing earthquake hazards is a topic of great importance. Dynamic earthquake hazard assessments resolved for a range of spatial scales and time scales will allow a more systematic approach to prioritizing the retrofitting of vulnerable structures, relocating populations at risk, protecting lifelines, preparing for disasters, and educating the public.

Distribution and Characteristics of Repeating Earthquakes in Northern California

NASA Astrophysics Data System (ADS)

Waldhauser, F.; Schaff, D. P.; Zechar, J. D.; Shaw, B. E.

2012-12-01

Repeating earthquakes are playing an increasingly important role in the study of fault processes and behavior, and have the potential to improve hazard assessment, earthquake forecast, and seismic monitoring capabilities. These events rupture the same fault patch repeatedly, generating virtually identical seismograms. In California, repeating earthquakes have been found predominately along the creeping section of the central San Andreas Fault, where they are believed to represent failing asperities on an otherwise creeping fault. Here, we use the northern California double-difference catalog of 450,000 precisely located events (1984-2009) and associated database of 2 billion waveform cross-correlation measurements to systematically search for repeating earthquakes across various tectonic regions. An initial search for pairs of earthquakes with high-correlation coefficients and similar magnitudes resulted in 4,610 clusters including a total of over 26,000 earthquakes. A subsequent double-difference re-analysis of these clusters resulted in 1,879 sequences (8,640 events) where a common rupture area can be resolved to the precision of a few tens of meters or less. These repeating earthquake sequences (RES) include between 3 and 24 events with magnitudes up to ML=4. We compute precise relative magnitudes between events in each sequence from differential amplitude measurements. Differences between these and standard coda-duration magnitudes have a standard deviation of 0.09. The RES occur throughout northern California, but RES with 10 or more events (6%) only occur along the central San Andreas and Calaveras faults. We are establishing baseline characteristics for each sequence, such as recurrence intervals and their coefficient of variation (CV), in order to compare them across tectonic regions. CVs for these clusters range from 0.002 to 2.6, indicating a range of behavior between periodic occurrence (CV~0), random occurrence, and temporal clustering. 10% of the RES

Database of potential sources for earthquakes larger than magnitude 6 in Northern California

USGS Publications Warehouse

,

1996-01-01

The Northern California Earthquake Potential (NCEP) working group, composed of many contributors and reviewers in industry, academia and government, has pooled its collective expertise and knowledge of regional tectonics to identify potential sources of large earthquakes in northern California. We have created a map and database of active faults, both surficial and buried, that forms the basis for the northern California portion of the national map of probabilistic seismic hazard. The database contains 62 potential sources, including fault segments and areally distributed zones. The working group has integrated constraints from broadly based plate tectonic and VLBI models with local geologic slip rates, geodetic strain rate, and microseismicity. Our earthquake source database derives from a scientific consensus that accounts for conflict in the diverse data. Our preliminary product, as described in this report brings to light many gaps in the data, including a need for better information on the proportion of deformation in fault systems that is aseismic.

Earthquake Hazard and Risk in New Zealand

NASA Astrophysics Data System (ADS)

Apel, E. V.; Nyst, M.; Fitzenz, D. D.; Molas, G.

2014-12-01

To quantify risk in New Zealand we examine the impact of updating the seismic hazard model. The previous RMS New Zealand hazard model is based on the 2002 probabilistic seismic hazard maps for New Zealand (Stirling et al., 2002). The 2015 RMS model, based on Stirling et al., (2012) will update several key source parameters. These updates include: implementation a new set of crustal faults including multi-segment ruptures, updating the subduction zone geometry and reccurrence rate and implementing new background rates and a robust methodology for modeling background earthquake sources. The number of crustal faults has increased by over 200 from the 2002 model, to the 2012 model which now includes over 500 individual fault sources. This includes the additions of many offshore faults in northern, east-central, and southwest regions. We also use the recent data to update the source geometry of the Hikurangi subduction zone (Wallace, 2009; Williams et al., 2013). We compare hazard changes in our updated model with those from the previous version. Changes between the two maps are discussed as well as the drivers for these changes. We examine the impact the hazard model changes have on New Zealand earthquake risk. Considered risk metrics include average annual loss, an annualized expected loss level used by insurers to determine the costs of earthquake insurance (and premium levels), and the loss exceedance probability curve used by insurers to address their solvency and manage their portfolio risk. We analyze risk profile changes in areas with large population density and for structures of economic and financial importance. New Zealand is interesting in that the city with the majority of the risk exposure in the country (Auckland) lies in the region of lowest hazard, where we don't have a lot of information about the location of faults and distributed seismicity is modeled by averaged Mw-frequency relationships on area sources. Thus small changes to the background rates

Great earthquakes along the Western United States continental margin: implications for hazards, stratigraphy and turbidite lithology

NASA Astrophysics Data System (ADS)

Nelson, C. H.; Gutiérrez Pastor, J.; Goldfinger, C.; Escutia, C.

2012-11-01

We summarize the importance of great earthquakes (Mw ≳ 8) for hazards, stratigraphy of basin floors, and turbidite lithology along the active tectonic continental margins of the Cascadia subduction zone and the northern San Andreas Transform Fault by utilizing studies of swath bathymetry visual core descriptions, grain size analysis, X-ray radiographs and physical properties. Recurrence times of Holocene turbidites as proxies for earthquakes on the Cascadia and northern California margins are analyzed using two methods: (1) radiometric dating (14C method), and (2) relative dating, using hemipelagic sediment thickness and sedimentation rates (H method). The H method provides (1) the best estimate of minimum recurrence times, which are the most important for seismic hazards risk analysis, and (2) the most complete dataset of recurrence times, which shows a normal distribution pattern for paleoseismic turbidite frequencies. We observe that, on these tectonically active continental margins, during the sea-level highstand of Holocene time, triggering of turbidity currents is controlled dominantly by earthquakes, and paleoseismic turbidites have an average recurrence time of ~550 yr in northern Cascadia Basin and ~200 yr along northern California margin. The minimum recurrence times for great earthquakes are approximately 300 yr for the Cascadia subduction zone and 130 yr for the northern San Andreas Fault, which indicates both fault systems are in (Cascadia) or very close (San Andreas) to the early window for another great earthquake. On active tectonic margins with great earthquakes, the volumes of mass transport deposits (MTDs) are limited on basin floors along the margins. The maximum run-out distances of MTD sheets across abyssal-basin floors along active margins are an order of magnitude less (~100 km) than on passive margins (~1000 km). The great earthquakes along the Cascadia and northern California margins cause seismic strengthening of the sediment, which

Earthquake Hazard for Aswan High Dam Area

NASA Astrophysics Data System (ADS)

Ismail, Awad

2016-04-01

Earthquake activity and seismic hazard analysis are important components of the seismic aspects for very essential structures such as major dams. The Aswan High Dam (AHD) created the second man-made reservoir in the world (Lake Nasser) and is constructed near urban areas pose a high-risk potential for downstream life and property. The Dam area is one of the seismically active regions in Egypt and is occupied with several cross faults, which are dominant in the east-west and north-south. Epicenters were found to cluster around active faults in the northern part of Lake and AHD location. The space-time distribution and the relation of the seismicity with the lake water level fluctuations were studied. The Aswan seismicity separates into shallow and deep seismic zones, between 0 and 14 and 14 and 30 km, respectively. These two seismic zones behave differently over time, as indicated by the seismicity rate, lateral extent, b-value, and spatial clustering. It is characterized by earthquake swarm sequences showing activation of the clustering-events over time and space. The effect of the North African drought (1982 to present) is clearly seen in the reservoir water level. As it decreased and left the most active fault segments uncovered, the shallow activity was found to be more sensitive to rapid discharging than to the filling. This study indicates that geology, topography, lineations in seismicity, offsets in the faults, changes in fault trends and focal mechanisms are closely related. No relation was found between earthquake activity and both-ground water table fluctuations and water temperatures measured in wells located around the Kalabsha area. The peak ground acceleration is estimated in the dam site based on strong ground motion simulation. This seismic hazard analyses have indicated that AHD is stable with the present seismicity. The earthquake epicenters have recently took place approximately 5 km west of the AHD structure. This suggests that AHD dam must be

St. Louis Area Earthquake Hazards Mapping Project

USGS Publications Warehouse

Williams, Robert A.; Steckel, Phyllis; Schweig, Eugene

2007-01-01

St. Louis has experienced minor earthquake damage at least 12 times in the past 200 years. Because of this history and its proximity to known active earthquake zones, the St. Louis Area Earthquake Hazards Mapping Project will produce digital maps that show variability of earthquake hazards in the St. Louis area. The maps will be available free via the internet. They can be customized by the user to show specific areas of interest, such as neighborhoods or transportation routes.

Washington Tsunami Hazard Mitigation Program

NASA Astrophysics Data System (ADS)

Walsh, T. J.; Schelling, J.

2012-12-01

Washington State has participated in the National Tsunami Hazard Mitigation Program (NTHMP) since its inception in 1995. We have participated in the tsunami inundation hazard mapping, evacuation planning, education, and outreach efforts that generally characterize the NTHMP efforts. We have also investigated hazards of significant interest to the Pacific Northwest. The hazard from locally generated earthquakes on the Cascadia subduction zone, which threatens tsunami inundation in less than hour following a magnitude 9 earthquake, creates special problems for low-lying accretionary shoreforms in Washington, such as the spits of Long Beach and Ocean Shores, where high ground is not accessible within the limited time available for evacuation. To ameliorate this problem, we convened a panel of the Applied Technology Council to develop guidelines for construction of facilities for vertical evacuation from tsunamis, published as FEMA 646, now incorporated in the International Building Code as Appendix M. We followed this with a program called Project Safe Haven (http://www.facebook.com/ProjectSafeHaven) to site such facilities along the Washington coast in appropriate locations and appropriate designs to blend with the local communities, as chosen by the citizens. This has now been completed for the entire outer coast of Washington. In conjunction with this effort, we have evaluated the potential for earthquake-induced ground failures in and near tsunami hazard zones to help develop cost estimates for these structures and to establish appropriate tsunami evacuation routes and evacuation assembly areas that are likely to to be available after a major subduction zone earthquake. We intend to continue these geotechnical evaluations for all tsunami hazard zones in Washington.

The Pacific Northwest; linkage between earthquake and volcano hazards

USGS Publications Warehouse

Crosson, R.S.

1990-01-01

The Pacific Northwest (Oregon, Washington, and northern California) is experiencing rapid industrial and population growth. The same conditions that make the region attractive- close proximity to both mountains and oceans, volcanoes and spectacular inland waters- also present significant geologic hazards that are easily overlooked in the normal timetable of human activities. The catastrophic eruption of Mount St. Helens 10 years ago serves as a dramatic reminder of the forces of nature that can be unleashed through volcanism. other volcanoes such as  mount Rainier, a majestic symbol of Washington, or Mount hood in Oregon, lie closer to population centers and could present far greater hazards should they become active. Earthquakes may affect even larger regions, prodcuging more cumulative damage. 

Space-Time Earthquake Rate Models for One-Year Hazard Forecasts in Oklahoma

NASA Astrophysics Data System (ADS)

Llenos, A. L.; Michael, A. J.

2017-12-01

The recent one-year seismic hazard assessments for natural and induced seismicity in the central and eastern US (CEUS) (Petersen et al., 2016, 2017) rely on earthquake rate models based on declustered catalogs (i.e., catalogs with foreshocks and aftershocks removed), as is common practice in probabilistic seismic hazard analysis. However, standard declustering can remove over 90% of some induced sequences in the CEUS. Some of these earthquakes may still be capable of causing damage or concern (Petersen et al., 2015, 2016). The choices of whether and how to decluster can lead to seismicity rate estimates that vary by up to factors of 10-20 (Llenos and Michael, AGU, 2016). Therefore, in order to improve the accuracy of hazard assessments, we are exploring ways to make forecasts based on full, rather than declustered, catalogs. We focus on Oklahoma, where earthquake rates began increasing in late 2009 mainly in central Oklahoma and ramped up substantially in 2013 with the expansion of seismicity into northern Oklahoma and southern Kansas. We develop earthquake rate models using the space-time Epidemic-Type Aftershock Sequence (ETAS) model (Ogata, JASA, 1988; Ogata, AISM, 1998; Zhuang et al., JASA, 2002), which characterizes both the background seismicity rate as well as aftershock triggering. We examine changes in the model parameters over time, focusing particularly on background rate, which reflects earthquakes that are triggered by external driving forces such as fluid injection rather than other earthquakes. After the model parameters are fit to the seismicity data from a given year, forecasts of the full catalog for the following year can then be made using a suite of 100,000 ETAS model simulations based on those parameters. To evaluate this approach, we develop pseudo-prospective yearly forecasts for Oklahoma from 2013-2016 and compare them with the observations using standard Collaboratory for the Study of Earthquake Predictability tests for consistency.

Earthquake Hazard Mitigation Using a Systems Analysis Approach to Risk Assessment

NASA Astrophysics Data System (ADS)

Legg, M.; Eguchi, R. T.

2015-12-01

The earthquake hazard mitigation goal is to reduce losses due to severe natural events. The first step is to conduct a Seismic Risk Assessment consisting of 1) hazard estimation, 2) vulnerability analysis, 3) exposure compilation. Seismic hazards include ground deformation, shaking, and inundation. The hazard estimation may be probabilistic or deterministic. Probabilistic Seismic Hazard Assessment (PSHA) is generally applied to site-specific Risk assessments, but may involve large areas as in a National Seismic Hazard Mapping program. Deterministic hazard assessments are needed for geographically distributed exposure such as lifelines (infrastructure), but may be important for large communities. Vulnerability evaluation includes quantification of fragility for construction or components including personnel. Exposure represents the existing or planned construction, facilities, infrastructure, and population in the affected area. Risk (expected loss) is the product of the quantified hazard, vulnerability (damage algorithm), and exposure which may be used to prepare emergency response plans, retrofit existing construction, or use community planning to avoid hazards. The risk estimate provides data needed to acquire earthquake insurance to assist with effective recovery following a severe event. Earthquake Scenarios used in Deterministic Risk Assessments provide detailed information on where hazards may be most severe, what system components are most susceptible to failure, and to evaluate the combined effects of a severe earthquake to the whole system or community. Casualties (injuries and death) have been the primary factor in defining building codes for seismic-resistant construction. Economic losses may be equally significant factors that can influence proactive hazard mitigation. Large urban earthquakes may produce catastrophic losses due to a cascading of effects often missed in PSHA. Economic collapse may ensue if damaged workplaces, disruption of utilities, and

76 FR 64325 - Advisory Committee on Earthquake Hazards Reduction Meeting

Federal Register 2010, 2011, 2012, 2013, 2014

2011-10-18

... Earthquake Hazards Reduction Meeting AGENCY: National Institute of Standards and Technology, Department of Commerce. ACTION: Notice of open meeting. SUMMARY: The Advisory Committee on Earthquake Hazards Reduction... relationship of Presidential Policy Directive/PPD-8: National Preparedness to National Earthquake Hazards...

2016 one-year seismic hazard forecast for the Central and Eastern United States from induced and natural earthquakes

USGS Publications Warehouse

Petersen, Mark D.; Mueller, Charles S.; Moschetti, Morgan P.; Hoover, Susan M.; Llenos, Andrea L.; Ellsworth, William L.; Michael, Andrew J.; Rubinstein, Justin L.; McGarr, Arthur F.; Rukstales, Kenneth S.

2016-03-28

The U.S. Geological Survey (USGS) has produced a 1-year seismic hazard forecast for 2016 for the Central and Eastern United States (CEUS) that includes contributions from both induced and natural earthquakes. The model assumes that earthquake rates calculated from several different time windows will remain relatively stationary and can be used to forecast earthquake hazard and damage intensity for the year 2016. This assessment is the first step in developing an operational earthquake forecast for the CEUS, and the analysis could be revised with updated seismicity and model parameters. Consensus input models consider alternative earthquake catalog durations, smoothing parameters, maximum magnitudes, and ground motion estimates, and represent uncertainties in earthquake occurrence and diversity of opinion in the science community. Ground shaking seismic hazard for 1-percent probability of exceedance in 1 year reaches 0.6 g (as a fraction of standard gravity [g]) in northern Oklahoma and southern Kansas, and about 0.2 g in the Raton Basin of Colorado and New Mexico, in central Arkansas, and in north-central Texas near Dallas. Near some areas of active induced earthquakes, hazard is higher than in the 2014 USGS National Seismic Hazard Model (NHSM) by more than a factor of 3; the 2014 NHSM did not consider induced earthquakes. In some areas, previously observed induced earthquakes have stopped, so the seismic hazard reverts back to the 2014 NSHM. Increased seismic activity, whether defined as induced or natural, produces high hazard. Conversion of ground shaking to seismic intensity indicates that some places in Oklahoma, Kansas, Colorado, New Mexico, Texas, and Arkansas may experience damage if the induced seismicity continues unabated. The chance of having Modified Mercalli Intensity (MMI) VI or greater (damaging earthquake shaking) is 5–12 percent per year in north-central Oklahoma and southern Kansas, similar to the chance of damage caused by natural earthquakes

Seismic hazard estimation of northern Iran using smoothed seismicity

NASA Astrophysics Data System (ADS)

Khoshnevis, Naeem; Taborda, Ricardo; Azizzadeh-Roodpish, Shima; Cramer, Chris H.

2017-07-01

This article presents a seismic hazard assessment for northern Iran, where a smoothed seismicity approach has been used in combination with an updated seismic catalog and a ground motion prediction equation recently found to yield good fit with data. We evaluate the hazard over a geographical area including the seismic zones of Azerbaijan, the Alborz Mountain Range, and Kopeh-Dagh, as well as parts of other neighboring seismic zones that fall within our region of interest. In the chosen approach, seismic events are not assigned to specific faults but assumed to be potential seismogenic sources distributed within regular grid cells. After performing the corresponding magnitude conversions, we decluster both historical and instrumental seismicity catalogs to obtain earthquake rates based on the number of events within each cell, and smooth the results to account for the uncertainty in the spatial distribution of future earthquakes. Seismicity parameters are computed for each seismic zone separately, and for the entire region of interest as a single uniform seismotectonic region. In the analysis, we consider uncertainties in the ground motion prediction equation, the seismicity parameters, and combine the resulting models using a logic tree. The results are presented in terms of expected peak ground acceleration (PGA) maps and hazard curves at selected locations, considering exceedance probabilities of 2 and 10% in 50 years for rock site conditions. According to our results, the highest levels of hazard are observed west of the North Tabriz and east of the North Alborz faults, where expected PGA values are between about 0.5 and 1 g for 10 and 2% probability of exceedance in 50 years, respectively. We analyze our results in light of similar estimates available in the literature and offer our perspective on the differences observed. We find our results to be helpful in understanding seismic hazard for northern Iran, but recognize that additional efforts are necessary to

Land-level changes from a late Holocene earthquake in the northern Puget lowland, Washington

USGS Publications Warehouse

Kelsey, H.M.; Sherrod, B.; Johnson, S.Y.; Dadisman, S.V.

2004-01-01

An earthquake, probably generated on the southern Whidbey Island fault zone, caused 1-2 m of ground-surface uplift on central Whidbey Island ???2800-3200 yr ago. The cause of the uplift is a fold that grew coseismically above a blind fault that was the earthquake source. Both the fault and the fold at the fault's tip are imaged on multichannel seismic refection profiles in Puget Sound immediately east of the central Whidbey Island site. Uplift is documented through contrasting histories of relative sea level at two coastal marshes on either side of the fault. Late Holocene shallow-crustal earthquakes of Mw = 6.5-7 pose substantial seismic hazard to the northern Puget Lowland. ?? 2004 Geological Society of America.

13 CFR 120.174 - Earthquake hazards.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 13 Business Credit and Assistance 1 2010-01-01 2010-01-01 false Earthquake hazards. 120.174 Section 120.174 Business Credit and Assistance SMALL BUSINESS ADMINISTRATION BUSINESS LOANS Policies Applying to All Business Loans Requirements Imposed Under Other Laws and Orders § 120.174 Earthquake...

Meeting of the Central and Eastern U.S. (CEUS) Earthquake Hazards Program October 28–29, 2009

USGS Publications Warehouse

Tuttle, Martitia; Boyd, Oliver; McCallister, Natasha

2013-01-01

On October 28th and 29th, 2009, the U.S. Geological Survey Earthquake Hazards Program held a meeting of Central and Eastern United States investigators and interested parties in Memphis, Tennessee. The purpose of the meeting was to bring together the Central and Eastern United States earthquake-hazards community to present and discuss recent research results, to promote communication and collaboration, to garner input regarding future research priorities, to inform the community about research opportunities afforded by the 2010–2012 arrival of EarthScope/USArray in the central United States, and to discuss plans for the upcoming bicentennial of the 1811–1812 New Madrid earthquakes. The two-day meeting included several keynote speakers, oral and poster presentations by attendees, and breakout sessions. The meeting is summarized in this report and can be subdivided into four primary sections: (1) summaries of breakout discussion groups; (2) list of meeting participants; (3) submitted abstracts; and (4) slide presentations. The abstracts and slides are included “as submitted” by the meeting participants and have not been subject to any formal peer review process; information contained in these sections reflects the opinions of the presenter at the time of the meeting and does not constitute endorsement by the U.S. Geological Survey.

75 FR 50749 - Advisory Committee on Earthquake Hazards Reduction Meeting

Federal Register 2010, 2011, 2012, 2013, 2014

2010-08-17

... Earthquake Hazards Reduction Meeting AGENCY: National Institute of Standards and Technology, Department of Commerce. ACTION: Notice of open meeting. SUMMARY: The Advisory Committee on Earthquake Hazards Reduction... on NEHRP earthquake related activities and to gather information for the 2011 Annual Report of the...

Spatial earthquake hazard assessment of Evansville, Indiana

USGS Publications Warehouse

Rockaway, T.D.; Frost, J.D.; Eggert, D.L.; Luna, R.

1997-01-01

The earthquake hazard has been evaluated for a 150-square-kilometer area around Evansville, Indiana. GIS-QUAKE, a system that combines liquefaction and ground motion analysis routines with site-specific geological, geotechnical, and seismological information, was used for the analysis. The hazard potential was determined by using 586 SPT borings, 27 CPT sounding, 39 shear-wave velocity profiles and synthesized acceleration records for body-wave magnitude 6.5 and 7.3 mid-continental earthquakes, occurring at distances of 50 km and 250 km, respectively. The results of the GIS-QUAKE hazard analyses for Evansville identify areas with a high hazard potential that had not previously been identified in earthquake zonation studies. The Pigeon Creek area specifically is identified as having significant potential for liquefaction-induced damage. Damage as a result of ground motion amplification is determined to be a moderate concern throughout the area. Differences in the findings of this zonation study and previous work are attributed to the size and range of the database, the hazard evaluation methodologies, and the geostatistical interpolation techniques used to estimate the hazard potential. Further, assumptions regarding the groundwater elevations made in previous studies are also considered to have had a significant effect on the results.

Playing against nature: improving earthquake hazard mitigation

NASA Astrophysics Data System (ADS)

Stein, S. A.; Stein, J.

2012-12-01

The great 2011 Tohoku earthquake dramatically demonstrated the need to improve earthquake and tsunami hazard assessment and mitigation policies. The earthquake was much larger than predicted by hazard models, and the resulting tsunami overtopped coastal defenses, causing more than 15,000 deaths and $210 billion damage. Hence if and how such defenses should be rebuilt is a challenging question, because the defences fared poorly and building ones to withstand tsunamis as large as March's is too expensive,. A similar issue arises along the Nankai Trough to the south, where new estimates warning of tsunamis 2-5 times higher than in previous models raise the question of what to do, given that the timescale on which such events may occur is unknown. Thus in the words of economist H. Hori, "What should we do in face of uncertainty? Some say we should spend our resources on present problems instead of wasting them on things whose results are uncertain. Others say we should prepare for future unknown disasters precisely because they are uncertain". Thus society needs strategies to mitigate earthquake and tsunami hazards that make economic and societal sense, given that our ability to assess these hazards is poor, as illustrated by highly destructive earthquakes that often occur in areas predicted by hazard maps to be relatively safe. Conceptually, we are playing a game against nature "of which we still don't know all the rules" (Lomnitz, 1989). Nature chooses tsunami heights or ground shaking, and society selects the strategy to minimize the total costs of damage plus mitigation costs. As in any game of chance, we maximize our expectation value by selecting the best strategy, given our limited ability to estimate the occurrence and effects of future events. We thus outline a framework to find the optimal level of mitigation by balancing its cost against the expected damages, recognizing the uncertainties in the hazard estimates. This framework illustrates the role of the

Earthquake Rate Models for Evolving Induced Seismicity Hazard in the Central and Eastern US

NASA Astrophysics Data System (ADS)

Llenos, A. L.; Ellsworth, W. L.; Michael, A. J.

2015-12-01

Injection-induced earthquake rates can vary rapidly in space and time, which presents significant challenges to traditional probabilistic seismic hazard assessment methodologies that are based on a time-independent model of mainshock occurrence. To help society cope with rapidly evolving seismicity, the USGS is developing one-year hazard models for areas of induced seismicity in the central and eastern US to forecast the shaking due to all earthquakes, including aftershocks which are generally omitted from hazards assessments (Petersen et al., 2015). However, the spatial and temporal variability of the earthquake rates make them difficult to forecast even on time-scales as short as one year. An initial approach is to use the previous year's seismicity rate to forecast the next year's seismicity rate. However, in places such as northern Oklahoma the rates vary so rapidly over time that a simple linear extrapolation does not accurately forecast the future, even when the variability in the rates is modeled with simulations based on an Epidemic-Type Aftershock Sequence (ETAS) model (Ogata, JASA, 1988) to account for earthquake clustering. Instead of relying on a fixed time period for rate estimation, we explore another way to determine when the earthquake rate should be updated. This approach could also objectively identify new areas where the induced seismicity hazard model should be applied. We will estimate the background seismicity rate by optimizing a single set of ETAS aftershock triggering parameters across the most active induced seismicity zones -- Oklahoma, Guy-Greenbrier, the Raton Basin, and the Azle-Dallas-Fort Worth area -- with individual background rate parameters in each zone. The full seismicity rate, with uncertainties, can then be estimated using ETAS simulations and changes in rate can be detected by applying change point analysis in ETAS transformed time with methods already developed for Poisson processes.

Deep-Sea Turbidites as Guides to Holocene Earthquake History at the Cascadia Subduction Zone—Alternative Views for a Seismic-Hazard Workshop

USGS Publications Warehouse

Atwater, Brian F.; Griggs, Gary B.

2012-01-01

This report reviews the geological basis for some recent estimates of earthquake hazards in the Cascadia region between southern British Columbia and northern California. The largest earthquakes to which the region is prone are in the range of magnitude 8-9. The source of these great earthquakes is the fault down which the oceanic Juan de Fuca Plate is being subducted or thrust beneath the North American Plate. Geologic evidence for their occurrence includes sedimentary deposits that have been observed in cores from deep-sea channels and fans. Earthquakes can initiate subaqueous slumps or slides that generate turbidity currents and which produce the sedimentary deposits known as turbidites. The hazard estimates reviewed in this report are derived mainly from deep-sea turbidites that have been interpreted as proxy records of great Cascadia earthquakes. The estimates were first published in 2008. Most of the evidence for them is contained in a monograph now in press. We have reviewed a small part of this evidence, chiefly from Cascadia Channel and its tributaries, all of which head offshore the Pacific coast of Washington State. According to the recent estimates, the Cascadia plate boundary ruptured along its full length in 19 or 20 earthquakes of magnitude 9 in the past 10,000 years; its northern third broke during these giant earthquakes only, and southern segments produced at least 20 additional, lesser earthquakes of Holocene age. The turbidite case for full-length ruptures depends on stratigraphic evidence for simultaneous shaking at the heads of multiple submarine canyons. The simultaneity has been inferred primarily from turbidite counts above a stratigraphic datum, sandy beds likened to strong-motion records, and radiocarbon ages adjusted for turbidity-current erosion. In alternatives proposed here, this turbidite evidence for simultaneous shaking is less sensitive to earthquake size and frequency than previously thought. Turbidites far below a channel

Making the Handoff from Earthquake Hazard Assessments to Effective Mitigation Measures (Invited)

NASA Astrophysics Data System (ADS)

Applegate, D.

2010-12-01

This year has witnessed a barrage of large earthquakes worldwide with the resulting damages ranging from inconsequential to truly catastrophic. We cannot predict when earthquakes will strike, but we can build communities that are resilient to strong shaking as well as to secondary hazards such as landslides and liquefaction. The contrasting impacts of the magnitude-7 earthquake that struck Haiti in January and the magnitude-8.8 event that struck Chile in April underscore the difference that mitigation and preparedness can make. In both cases, millions of people were exposed to severe shaking, but deaths in Chile were measured in the hundreds rather than the hundreds of thousands that perished in Haiti. Numerous factors contributed to these disparate outcomes, but the most significant is the presence of strong building codes in Chile and their total absence in Haiti. The financial cost of the Chilean earthquake still represents an unacceptably high percentage of that nation’s gross domestic product, a reminder that life safety is the paramount, but not the only, goal of disaster risk reduction measures. For building codes to be effective, both in terms of lives saved and economic cost, they need to reflect the hazard as accurately as possible. As one of four federal agencies that make up the congressionally mandated National Earthquake Hazards Reduction Program (NEHRP), the U.S. Geological Survey (USGS) develops national seismic hazard maps that form the basis for seismic provisions in model building codes through the Federal Emergency Management Agency and private-sector practitioners. This cooperation is central to NEHRP, which both fosters earthquake research and establishes pathways to translate research results into implementation measures. That translation depends on the ability of hazard-focused scientists to interact and develop mutual trust with risk-focused engineers and planners. Strengthening that interaction is an opportunity for the next generation

Perspectives on earthquake hazards in the New Madrid seismic zone, Missouri

DOE Office of Scientific and Technical Information (OSTI.GOV)

Thenhaus, P.C.

1990-01-01

A sequence of three great earthquakes struck the Central United States during the winter of 1811-12 in the area of New Madrid, Missouri. They are considered to be the greatest earthquakes in the conterminous U.S. because they were felt and caused damage at far greater distances than any other earthquakes in US history. In contrast to California, where earthquakes are felt frequently, the damaging earthquakes that have occurred in the Eastern US are generally regarded as only historical phenomena. A fundamental problem in the Eastern US, therefore, is that the earthquake hazard is not generally considered today in land-use andmore » civic planning. This article offers perspectives on the earthquake hazard of the New Madrid seismic zone through discussions of the geology of the Mississippi Embayment, the historical earthquakes that have occurred there, the earthquake risk, and the tools that geoscientists have to study the region. The so-called earthquake hazard is defined by the characterization of the physical attributes of the geological structures that cause earthquakes, the estimation of the recurrence times of the earthquakes, their potential size, and the expected ground motions. The term earthquake risk, on the other hand, refers to aspects of the expected damage to manmade structures and to lifelines as a result of the earthquake hazard.« less

Updated earthquake catalogue for seismic hazard analysis in Pakistan

NASA Astrophysics Data System (ADS)

Khan, Sarfraz; Waseem, Muhammad; Khan, Muhammad Asif; Ahmed, Waqas

2018-03-01

A reliable and homogenized earthquake catalogue is essential for seismic hazard assessment in any area. This article describes the compilation and processing of an updated earthquake catalogue for Pakistan. The earthquake catalogue compiled in this study for the region (quadrangle bounded by the geographical limits 40-83° N and 20-40° E) includes 36,563 earthquake events, which are reported as 4.0-8.3 moment magnitude (M W) and span from 25 AD to 2016. Relationships are developed between the moment magnitude and body, and surface wave magnitude scales to unify the catalogue in terms of magnitude M W. The catalogue includes earthquakes from Pakistan and neighbouring countries to minimize the effects of geopolitical boundaries in seismic hazard assessment studies. Earthquakes reported by local and international agencies as well as individual catalogues are included. The proposed catalogue is further used to obtain magnitude of completeness after removal of dependent events by using four different algorithms. Finally, seismicity parameters of the seismic sources are reported, and recommendations are made for seismic hazard assessment studies in Pakistan.

Assessment of seismic hazards along the northern Gulf of Aqaba

NASA Astrophysics Data System (ADS)

Abueladas, Abdel-Rahman Aqel

Aqaba and Elat are very important port and recreation cities for the Hashemite Kingdom of Jordan and Israel, respectively. The two cities are the most susceptible to damage from a destructive future earthquake because they are located over the tectonically active Dead Sea transform fault (DST) that is the source of most of the major historical earthquakes in the region. The largest twentieth century earthquake on the DST, the magnitude Mw 7.2 Nuweiba earthquake of November 22, 1995, caused damage to structures in both cities. The integration of geological, geophysical, and earthquake engineering studies will help to assess the seismic hazards by determining the location and slip potential of active faults and by mapping areas of high liquefaction susceptibility. Ground Penetrating Radar (GPR) as a high resolution shallow geophysical tool was used to map the shallow active faults in Aqaba, Taba Sabkha area, and Elat. The GPR data revealed the onshore continuation of the Evrona, West Aqaba, Aqaba fault zones, and several transverse faults. The integration of offshore and onshore data confirm the extension of these faults along both sides of the Gulf of Aqaba. A 3D model of GPR data at one site in Aqaba indicates that the NW-trending transverse faults right laterally offset older than NE-trending faults. The most hazardous fault is the Evrona fault which extends north to the Tabs Sabkha. A geographic information system (GIS) database of the seismic hazard was created in order to facilitate the analyzing, manipulation, and updating of the input parameters. Liquefaction potential maps were created for the region based on analysis of borehole data. The liquefaction map shows high and moderate liquefaction susceptibility zones along the northern coast of the Gulf of Aqaba. In Aqaba several hotels are located within a high and moderate liquefaction zones. The Yacht Club, Aqaba, Ayla archaeological site, and a part of commercial area are also situated in a risk area. A part

Assessing the earthquake hazards in urban areas

USGS Publications Warehouse

Hays, W.W.; Gori, P.L.; Kockelman, W.J.

1988-01-01

Major urban areas in widely scattered geographic locations across the United States are a t varying degrees of risk from earthquakes. the locations of these urban areas include Charleston, South Carolina; Memphis Tennessee; St.Louis, Missouri; Salt Lake City, Utah; Seattle-Tacoma, Washington; Portland, Oregon; and Anchorage, Alaska; even Boston, Massachusetts, and Buffalo New York, have a history of large earthquakes. Cooperative research during the past decade has focused on assessing the nature and degree of the risk or seismic hazard i nthe broad geographic regions around each urban area. The strategy since the 1970's has been to bring together local, State, and Federal resources to solve the problem of assessing seismic risk. Successfl sooperative programs have been launched in the San Francisco Bay and Los Angeles regions in California and the Wasatch Front region in Utah. 

Issues on the Japanese Earthquake Hazard Evaluation

NASA Astrophysics Data System (ADS)

Hashimoto, M.; Fukushima, Y.; Sagiya, T.

2013-12-01

The 2011 Great East Japan Earthquake forced the policy of counter-measurements to earthquake disasters, including earthquake hazard evaluations, to be changed in Japan. Before the March 11, Japanese earthquake hazard evaluation was based on the history of earthquakes that repeatedly occurs and the characteristic earthquake model. The source region of an earthquake was identified and its occurrence history was revealed. Then the conditional probability was estimated using the renewal model. However, the Japanese authorities changed the policy after the megathrust earthquake in 2011 such that the largest earthquake in a specific seismic zone should be assumed on the basis of available scientific knowledge. According to this policy, three important reports were issued during these two years. First, the Central Disaster Management Council issued a new estimate of damages by a hypothetical Mw9 earthquake along the Nankai trough during 2011 and 2012. The model predicts a 34 m high tsunami on the southern Shikoku coast and intensity 6 or higher on the JMA scale in most area of Southwest Japan as the maximum. Next, the Earthquake Research Council revised the long-term earthquake hazard evaluation of earthquakes along the Nankai trough in May 2013, which discarded the characteristic earthquake model and put much emphasis on the diversity of earthquakes. The so-called 'Tokai' earthquake was negated in this evaluation. Finally, another report by the CDMC concluded that, with the current knowledge, it is hard to predict the occurrence of large earthquakes along the Nankai trough using the present techniques, based on the diversity of earthquake phenomena. These reports created sensations throughout the country and local governments are struggling to prepare counter-measurements. These reports commented on large uncertainty in their evaluation near their ends, but are these messages transmitted properly to the public? Earthquake scientists, including authors, are involved in

The MITMOTION Project - A seismic hazard overview of the Mitidja Basin (Northern Algeria)

NASA Astrophysics Data System (ADS)

Borges, José; Ouyed, Merzouk; Bezzeghoud, Mourad; Idres, Mouloud; Caldeira, Bento; Boughacha, Mohamed; Carvalho, João; Samai, Saddek; Fontiela, João; Aissa, Saoussen; Benfadda, Amar; Chimouni, Redouane; Yalaoui, Rafik; Dias, Rui

2017-04-01

The Mitidja Basin (MB) is located in northern Algeria and is filled by quaternary sediments with a length of about 100 km on the EW direction and approximately 20 km width. This basin is limited to the south by the Boumerdes - Larbaa - Blida active fault system and to the north by the Thenia - Sahel fault system. Both fault systems are of the reverse type with opposed dips and accommodate a general slip rate of 4 mm/year. This basin is associated with important seismic events that affected northern Algeria since the historical period until the present. The available earthquake catalogues reported numerous destructive earthquakes that struke different regions, such as Algiers (1365, Io= X; 1716, Io = X). Recently, on May 2003 the Bourmedes earthquake (Mw = 6.9) affected the area of Zemmouri and caused 2.271 deaths. The event was caused by the reactivation of the MB boundary faults. The epicenter was located offshore and generated a maximum uplift of 0.8 m along the coast with a horizontal maximum slip of 0.24 m. Recent studies show that the Boumerdes earthquake overloaded the system of adjacent faults with a stress increase between 0.4 and 1.5 bar. This induced an increase of the seismic hazard potential of the region and recommends a more detailed study of this fault system. The high seismogenic potential of the fault system bordering the MB, the exposure to danger of the most densely populated region of Algiers and the amplification effect caused by the basin are the motivation for this project proposal that will focus on the evaluation of the seismic hazard of the region. The general purpose of the project is to improve the seismic hazard assessment on the MB producing realistic predictions of strong ground motion caused by moderate and large earthquakes. To achieve this objective, it is important to make an effort in 3 directions: 1) the development of a detailed 3D velocity/structure model of the MB that includes geological constraints, seismic reflection data

Continuing megathrust earthquake potential in Chile after the 2014 Iquique earthquake

USGS Publications Warehouse

Hayes, Gavin P.; Herman, Matthew W.; Barnhart, William D.; Furlong, Kevin P.; Riquelme, Sebástian; Benz, Harley M.; Bergman, Eric; Barrientos, Sergio; Earle, Paul S.; Samsonov, Sergey

2014-01-01

The seismic gap theory identifies regions of elevated hazard based on a lack of recent seismicity in comparison with other portions of a fault. It has successfully explained past earthquakes (see, for example, ref. 2) and is useful for qualitatively describing where large earthquakes might occur. A large earthquake had been expected in the subduction zone adjacent to northern Chile which had not ruptured in a megathrust earthquake since a M ~8.8 event in 1877. On 1 April 2014 a M 8.2 earthquake occurred within this seismic gap. Here we present an assessment of the seismotectonics of the March–April 2014 Iquique sequence, including analyses of earthquake relocations, moment tensors, finite fault models, moment deficit calculations and cumulative Coulomb stress transfer. This ensemble of information allows us to place the sequence within the context of regional seismicity and to identify areas of remaining and/or elevated hazard. Our results constrain the size and spatial extent of rupture, and indicate that this was not the earthquake that had been anticipated. Significant sections of the northern Chile subduction zone have not ruptured in almost 150 years, so it is likely that future megathrust earthquakes will occur to the south and potentially to the north of the 2014 Iquique sequence.

Continuing megathrust earthquake potential in Chile after the 2014 Iquique earthquake.

PubMed

Hayes, Gavin P; Herman, Matthew W; Barnhart, William D; Furlong, Kevin P; Riquelme, Sebástian; Benz, Harley M; Bergman, Eric; Barrientos, Sergio; Earle, Paul S; Samsonov, Sergey

2014-08-21

The seismic gap theory identifies regions of elevated hazard based on a lack of recent seismicity in comparison with other portions of a fault. It has successfully explained past earthquakes (see, for example, ref. 2) and is useful for qualitatively describing where large earthquakes might occur. A large earthquake had been expected in the subduction zone adjacent to northern Chile, which had not ruptured in a megathrust earthquake since a M ∼8.8 event in 1877. On 1 April 2014 a M 8.2 earthquake occurred within this seismic gap. Here we present an assessment of the seismotectonics of the March-April 2014 Iquique sequence, including analyses of earthquake relocations, moment tensors, finite fault models, moment deficit calculations and cumulative Coulomb stress transfer. This ensemble of information allows us to place the sequence within the context of regional seismicity and to identify areas of remaining and/or elevated hazard. Our results constrain the size and spatial extent of rupture, and indicate that this was not the earthquake that had been anticipated. Significant sections of the northern Chile subduction zone have not ruptured in almost 150 years, so it is likely that future megathrust earthquakes will occur to the south and potentially to the north of the 2014 Iquique sequence.

Earthquake hazard assessment after Mexico (1985).

PubMed

Degg, M R

1989-09-01

The 1985 Mexican earthquake ranks foremost amongst the major earthquake disasters of the twentieth century. One of the few positive aspects of the disaster is that it provided massive quantities of data that would otherwise have been unobtainable. Every opportunity should be taken to incorporate the findings from these data in earthquake hazard assessments. The purpose of this paper is to provide a succinct summary of some of the more important lessons from Mexico. It stems from detailed field investigations, and subsequent analyses, conducted by the author on the behalf of reinsurance companies.

Deviant Earthquakes: Data-driven Constraints on the Variability in Earthquake Source Properties and Seismic Hazard

NASA Astrophysics Data System (ADS)

Trugman, Daniel Taylor

The complexity of the earthquake rupture process makes earthquakes inherently unpredictable. Seismic hazard forecasts often presume that the rate of earthquake occurrence can be adequately modeled as a space-time homogenenous or stationary Poisson process and that the relation between the dynamical source properties of small and large earthquakes obey self-similar scaling relations. While these simplified models provide useful approximations and encapsulate the first-order statistical features of the historical seismic record, they are inconsistent with the complexity underlying earthquake occurrence and can lead to misleading assessments of seismic hazard when applied in practice. The six principle chapters of this thesis explore the extent to which the behavior of real earthquakes deviates from these simplified models, and the implications that the observed deviations have for our understanding of earthquake rupture processes and seismic hazard. Chapter 1 provides a brief thematic overview and introduction to the scope of this thesis. Chapter 2 examines the complexity of the 2010 M7.2 El Mayor-Cucapah earthquake, focusing on the relation between its unexpected and unprecedented occurrence and anthropogenic stresses from the nearby Cerro Prieto Geothermal Field. Chapter 3 compares long-term changes in seismicity within California's three largest geothermal fields in an effort to characterize the relative influence of natural and anthropogenic stress transients on local seismic hazard. Chapter 4 describes a hybrid, hierarchical clustering algorithm that can be used to relocate earthquakes using waveform cross-correlation, and applies the new algorithm to study the spatiotemporal evolution of two recent seismic swarms in western Nevada. Chapter 5 describes a new spectral decomposition technique that can be used to analyze the dynamic source properties of large datasets of earthquakes, and applies this approach to revisit the question of self-similar scaling of

Perspectives on earthquake hazards in the New Madrid seismic zone, Missouri

USGS Publications Warehouse

Thenhaus, P.C.

1990-01-01

A sequence of three great earthquakes struck the Central United States during the winter of 1811-1812 in the area of New Madrid, Missouri. they are considered to be the greatest earthquakes in the conterminous U.S because they were felt and caused damage at far greater distances than any other earthquakes in U.S history. The large population currently living within the damage area of these earthquakes means that widespread destruction and loss of life is likely if the sequence were repeated. In contrast to California, where the earthquakes are felt frequently, the damaging earthquakes that have occurred in the Easter U.S-in 155 (Cape Ann, Mass.), 1811-12 (New Madrid, Mo.), 1886 (Charleston S.C) ,and 1897 (Giles County, Va.- are generally regarded as only historical phenomena (fig. 1). The social memory of these earthquakes no longer exists. A fundamental problem in the Eastern U.S, therefore, is that the earthquake hazard is not generally considered today in land-use and civic planning. This article offers perspectives on the earthquake hazard of the New Madrid seismic zone through discussions of the geology of the Mississippi Embayment, the historical earthquakes that have occurred there, the earthquake risk, and the "tools" that geoscientists have to study the region. The so-called earthquake hazard is defined  by the characterization of the physical attributes of the geological structures that cause earthquakes, the estimation of the recurrence times of the earthquakes, the estimation of the recurrence times of the earthquakes, their potential size, and the expected ground motions. the term "earthquake risk," on the other hand, refers to aspects of the expected damage to manmade strctures and to lifelines as a result of the earthquake hazard.  

Are seismic hazard assessment errors and earthquake surprises unavoidable?

NASA Astrophysics Data System (ADS)

Kossobokov, Vladimir

2013-04-01

Why earthquake occurrences bring us so many surprises? The answer seems evident if we review the relationships that are commonly used to assess seismic hazard. The time-span of physically reliable Seismic History is yet a small portion of a rupture recurrence cycle at an earthquake-prone site, which makes premature any kind of reliable probabilistic statements about narrowly localized seismic hazard. Moreover, seismic evidences accumulated to-date demonstrate clearly that most of the empirical relations commonly accepted in the early history of instrumental seismology can be proved erroneous when testing statistical significance is applied. Seismic events, including mega-earthquakes, cluster displaying behaviors that are far from independent or periodic. Their distribution in space is possibly fractal, definitely, far from uniform even in a single segment of a fault zone. Such a situation contradicts generally accepted assumptions used for analytically tractable or computer simulations and complicates design of reliable methodologies for realistic earthquake hazard assessment, as well as search and definition of precursory behaviors to be used for forecast/prediction purposes. As a result, the conclusions drawn from such simulations and analyses can MISLEAD TO SCIENTIFICALLY GROUNDLESS APPLICATION, which is unwise and extremely dangerous in assessing expected societal risks and losses. For example, a systematic comparison of the GSHAP peak ground acceleration estimates with those related to actual strong earthquakes, unfortunately, discloses gross inadequacy of this "probabilistic" product, which appears UNACCEPTABLE FOR ANY KIND OF RESPONSIBLE SEISMIC RISK EVALUATION AND KNOWLEDGEABLE DISASTER PREVENTION. The self-evident shortcomings and failures of GSHAP appeals to all earthquake scientists and engineers for an urgent revision of the global seismic hazard maps from the first principles including background methodologies involved, such that there becomes: (a) a

The Mw 7.7 Bhuj earthquake: Global lessons for earthquake hazard in intra-plate regions

USGS Publications Warehouse

Schweig, E.; Gomberg, J.; Petersen, M.; Ellis, M.; Bodin, P.; Mayrose, L.; Rastogi, B.K.

2003-01-01

The Mw 7.7 Bhuj earthquake occurred in the Kachchh District of the State of Gujarat, India on 26 January 2001, and was one of the most damaging intraplate earthquakes ever recorded. This earthquake is in many ways similar to the three great New Madrid earthquakes that occurred in the central United States in 1811-1812, An Indo-US team is studying the similarities and differences of these sequences in order to learn lessons for earthquake hazard in intraplate regions. Herein we present some preliminary conclusions from that study. Both the Kutch and New Madrid regions have rift type geotectonic setting. In both regions the strain rates are of the order of 10-9/yr and attenuation of seismic waves as inferred from observations of intensity and liquefaction are low. These strain rates predict recurrence intervals for Bhuj or New Madrid sized earthquakes of several thousand years or more. In contrast, intervals estimated from paleoseismic studies and from other independent data are significantly shorter, probably hundreds of years. All these observations together may suggest that earthquakes relax high ambient stresses that are locally concentrated by rheologic heterogeneities, rather than loading by plate-tectonic forces. The latter model generally underlies basic assumptions made in earthquake hazard assessment, that the long-term average rate of energy released by earthquakes is determined by the tectonic loading rate, which thus implies an inherent average periodicity of earthquake occurrence. Interpreting the observations in terms of the former model therefore may require re-examining the basic assumptions of hazard assessment.

77 FR 64314 - Advisory Committee on Earthquake Hazards Reduction Meeting

Federal Register 2010, 2011, 2012, 2013, 2014

2012-10-19

... is to discuss engineering needs for existing buildings, to review the National Earthquake Hazards... Committee business. The final agenda will be posted on the NEHRP Web site at http://nehrp.gov/ . DATES: The... assesses: Trends and developments in the science and engineering of earthquake hazards reduction; The...

Hazard Assessment and Early Warning of Tsunamis: Lessons from the 2011 Tohoku earthquake

NASA Astrophysics Data System (ADS)

Satake, K.

2012-12-01

The March 11, 2011 Tohoku earthquake (M 9.0) was the largest earthquake in Japanese history, and was the best recorded subduction-zone earthquakes in the world. In particular, various offshore geophysical observations revealed large horizontal and vertical seafloor movements, and the tsunami was recorded on high-quality, high-sampling gauges. Analysis of such tsunami waveforms shows a temporal and spatial slip distribution during the 2011 Tohoku earthquake. The fault rupture started near the hypocenter and propagated into both deep and shallow parts of the plate interface. Very large, ~25 m, slip off Miyagi on the deep part of plate interface corresponds to an interplate earthquake of M 8.8, the location and size similar to 869 Jogan earthquake model, and was responsible for the large tsunami inundation in Sendai and Ishinomaki plains. Huge slip, more than 50 m, occurred on the shallow part near the trench axis ~3 min after the earthquake origin time. This delayed shallow rupture (M 8.8) was similar to the 1896 "tsunami earthquake," and was responsible for the large tsunami on the northern Sanriku coast, measured at ~100 km north of the largest slip. Thus the Tohoku earthquake can be decomposed into an interplate earthquake and the triggered "tsunami earthquake." The Japan Meteorological Agency issued tsunami warning 3 minutes after the earthquake, and saved many lives. However, their initial estimation of tsunami height was underestimated, because the earthquake magnitude was initially estimated as M 7.9, hence the computed tsunami heights were lower. The JMA attempts to improve the tsunami warning system, including technical developments to estimate the earthquake size in a few minutes by using various and redundant information, to deploy and utilize the offshore tsunami observations, and to issue a warning based on the worst case scenario if a possibility of giant earthquake exists. Predicting a trigger of another large earthquake would still be a challenge

Earthquake Hazard and Risk in Alaska

NASA Astrophysics Data System (ADS)

Black Porto, N.; Nyst, M.

2014-12-01

Alaska is one of the most seismically active and tectonically diverse regions in the United States. To examine risk, we have updated the seismic hazard model in Alaska. The current RMS Alaska hazard model is based on the 2007 probabilistic seismic hazard maps for Alaska (Wesson et al., 2007; Boyd et al., 2007). The 2015 RMS model will update several key source parameters, including: extending the earthquake catalog, implementing a new set of crustal faults, updating the subduction zone geometry and reoccurrence rate. First, we extend the earthquake catalog to 2013; decluster the catalog, and compute new background rates. We then create a crustal fault model, based on the Alaska 2012 fault and fold database. This new model increased the number of crustal faults from ten in 2007, to 91 faults in the 2015 model. This includes the addition of: the western Denali, Cook Inlet folds near Anchorage, and thrust faults near Fairbanks. Previously the subduction zone was modeled at a uniform depth. In this update, we model the intraslab as a series of deep stepping events. We also use the best available data, such as Slab 1.0, to update the geometry of the subduction zone. The city of Anchorage represents 80% of the risk exposure in Alaska. In the 2007 model, the hazard in Alaska was dominated by the frequent rate of magnitude 7 to 8 events (Gutenberg-Richter distribution), and large magnitude 8+ events had a low reoccurrence rate (Characteristic) and therefore didn't contribute as highly to the overall risk. We will review these reoccurrence rates, and will present the results and impact to Anchorage. We will compare our hazard update to the 2007 USGS hazard map, and discuss the changes and drivers for these changes. Finally, we will examine the impact model changes have on Alaska earthquake risk. Consider risk metrics include average annual loss, an annualized expected loss level used by insurers to determine the costs of earthquake insurance (and premium levels), and the

Landslide Hazards After the 2005 Kashmir Earthquake

NASA Astrophysics Data System (ADS)

Bulmer, Mark; Farquhar, Tony; Roshan, Masud; Akhtar, Sadar Saeed; Wahla, Sajjad Karamat

2007-01-01

The 8 October 2005 Kashmir earthquake killed 87,300 people and disrupted the lives of several million more. By current estimates, 30,000 still live in camps sited more in accordance with short term expedience than with freedom from risk of natural hazards. In December 2006, the international aid community expressed fears that 50,000 people in Northwest Frontier Province may leave their mountain homes this winter as landslides and avalanches block access roads. As the focus of humanitarian assistance shifts toward restoration of Kashmir's infrastructure, it is important that the persistent hazard of landslides within the earthquake affected region be understood and recognized.

The Salton Seismic Imaging Project (SSIP): Rift Processes and Earthquake Hazards in the Salton Trough (Invited)

NASA Astrophysics Data System (ADS)

Hole, J. A.; Stock, J. M.; Fuis, G. S.; Rymer, M. J.; Murphy, J. M.; Sickler, R. R.; Criley, C. J.; Goldman, M.; Catchings, R. D.; Ricketts, J. W.; Gonzalez-Fernandez, A.; Driscoll, N.; Kent, G.; Harding, A. J.; Klemperer, S. L.

2009-12-01

The Salton Seismic Imaging Project (SSIP) and coordinated projects will acquire seismic data in and across the Salton Trough in southern California and northern Mexico, including the Coachella, Imperial, and Mexicali Valleys. These projects address both rifting processes at the northern end of the Gulf of California extensional province and earthquake hazards at the southern end of the San Andreas Fault system. In the central Salton Trough, North American lithosphere appears to have been rifted completely apart. Based primarily on a 1979 seismic refraction project, the 20-22 km thick crust is apparently composed entirely of new crust added by magmatism from below and sedimentation from above. The new data will constrain the style of continental breakup, the role and mode of magmatism, the effects of rapid Colorado River sedimentation upon extension and magmatism, and the partitioning of oblique extension. The southernmost San Andreas Fault is considered at high risk of producing a large damaging earthquake, yet structures of the fault and adjacent basins are poorly constrained. To improve hazard models, SSIP will image the geometry of the San Andreas and Imperial Faults, structure of sedimentary basins in the Salton Trough, and three-dimensional seismic velocity of the crust and uppermost mantle. SSIP and collaborating projects have been funded by several different programs at NSF and the USGS. These projects include seven lines of land refraction and low-fold reflection data, airguns and OBS data in the Salton Sea, coordinated fieldwork for onshore-offshore and 3-D data, and a densely sampled line of broadband stations across the trough. Fieldwork is tentatively scheduled for 2010. Preliminary work in 2009 included calibration shots in the Imperial Valley that quantified strong ground motion and proved lack of harm to agricultural irrigation tile drains from explosive shots. Piggyback and complementary studies are encouraged.

The Active Fault Parameters for Time-Dependent Earthquake Hazard Assessment in Taiwan

NASA Astrophysics Data System (ADS)

Lee, Y.; Cheng, C.; Lin, P.; Shao, K.; Wu, Y.; Shih, C.

2011-12-01

Taiwan is located at the boundary between the Philippine Sea Plate and the Eurasian Plate, with a convergence rate of ~ 80 mm/yr in a ~N118E direction. The plate motion is so active that earthquake is very frequent. In the Taiwan area, disaster-inducing earthquakes often result from active faults. For this reason, it's an important subject to understand the activity and hazard of active faults. The active faults in Taiwan are mainly located in the Western Foothills and the Eastern longitudinal valley. Active fault distribution map published by the Central Geological Survey (CGS) in 2010 shows that there are 31 active faults in the island of Taiwan and some of which are related to earthquake. Many researchers have investigated these active faults and continuously update new data and results, but few people have integrated them for time-dependent earthquake hazard assessment. In this study, we want to gather previous researches and field work results and then integrate these data as an active fault parameters table for time-dependent earthquake hazard assessment. We are going to gather the seismic profiles or earthquake relocation of a fault and then combine the fault trace on land to establish the 3D fault geometry model in GIS system. We collect the researches of fault source scaling in Taiwan and estimate the maximum magnitude from fault length or fault area. We use the characteristic earthquake model to evaluate the active fault earthquake recurrence interval. In the other parameters, we will collect previous studies or historical references and complete our parameter table of active faults in Taiwan. The WG08 have done the time-dependent earthquake hazard assessment of active faults in California. They established the fault models, deformation models, earthquake rate models, and probability models and then compute the probability of faults in California. Following these steps, we have the preliminary evaluated probability of earthquake-related hazards in certain

Great Earthquakes and Tsunami Day for Teachers on the Leading Edge: Geologic Hazards and Links to EarthScope in a Field-Based Program

NASA Astrophysics Data System (ADS)

Butler, R.; Bishop, E. M.; Ault, C.; Magura, B.; Hedeen, C.; Connor, D.; Southworth-Neumeyer, T.; Conrey, R.

2005-12-01

Inviting K-12 science teachers into the field to observe the work of professional geologists and engage in learning that is scientifically important and socially relevant deepens their geologic understanding while instilling enthusiasm for inquiry-based instruction. "Teachers on the Leading Edge" (TOTLE) is a field-based and place-based teacher development program that features active continental margin geology of the Pacific Northwest. Program themes include: (1) Geophysics as fundamental to understanding plate tectonics and essential to deciphering Pacific Northwest geology that underlies a tree-covered landscape; and (2) Geologic Hazards as understandable and inevitable consequences of living on the leading edge of our continent. The two-week TOTLE 2005 field workshop traversed the active continental margin of Oregon from the Pacific Coast through the Cascade Range to accreted terranes along the Snake River. "Great Earthquakes and Tsunami Day" featured introductions to earthquake seismology and paleoseismology. Presentations on earthquake seismology with examples from the December 2004 Sumatra - Andaman earthquake and Indian Ocean tsunami provided context and background. During a morning low tide near Fort Clatsop south of Astoria, paleoseismologist Brian Atwater (USGS, Seattle) helped teachers observe and interpret drowned forests and tsunami deposits that mark four great Cascadia earthquakes of the past 2000 years. That afternoon, Darci Connor, former Tsunami Outreach Coordinator for the City of Seaside, helped teachers understand their critical role in educating K-12 students about natural hazard preparedness. In the evening, TOTLE teachers crafted their new understanding of great earthquakes and tsunami into interactive learning activities for Science Campers at Camp Kiwanilong operated by the Oregon Museum of Science and Industry. These experiences make frontier geophysical research, like GPS observations of slow earthquakes and seismic tomography of the

St. Louis Area Earthquake Hazards Mapping Project - A Progress Report-November 2008

USGS Publications Warehouse

Karadeniz, D.; Rogers, J.D.; Williams, R.A.; Cramer, C.H.; Bauer, R.A.; Hoffman, D.; Chung, J.; Hempen, G.L.; Steckel, P.H.; Boyd, O.L.; Watkins, C.M.; McCallister, N.S.; Schweig, E.

2009-01-01

St. Louis has experienced minor earthquake damage at least 12 times in the past 200 years. Because of this history and its proximity to known active earthquake zones, the St. Louis Area Earthquake Hazards Mapping Project (SLAEHMP) is producing digital maps that show variability of earthquake hazards, including liquefaction and ground shaking, in the St. Louis area. The maps will be available free via the internet. Although not site specific enough to indicate the hazard at a house-by-house resolution, they can be customized by the user to show specific areas of interest, such as neighborhoods or transportation routes. Earthquakes currently cannot be predicted, but scientists can estimate how strongly the ground is likely to shake as the result of an earthquake. Earthquake hazard maps provide one way of conveying such estimates. The U.S. Geological Survey (USGS), which produces earthquake hazard maps for the Nation, is working with local partners to develop detailed maps for urban areas vulnerable to strong ground shaking. These partners, which along with the USGS comprise the SLAEHMP, include the Missouri University of Science and Technology-Rolla (Missouri S&T), Missouri Department of Natural Resources (MDNR), Illinois State Geological Survey (ISGS), Saint Louis University, Missouri State Emergency Management Agency, and URS Corporation. Preliminary hazard maps covering a test portion of the 29-quadrangle St. Louis study area have been produced and are currently being evaluated by the SLAEHMP. A USGS Fact Sheet summarizing this project was produced and almost 1000 copies have been distributed at several public outreach meetings and field trips that have featured the SLAEHMP (Williams and others, 2007). In addition, a USGS website focusing on the SLAEHMP, which provides links to project results and relevant earthquake hazard information, can be found at: http://earthquake.usgs.gov/regional/ceus/urban_map/st_louis/index.php. This progress report summarizes the

How Can Museum Exhibits Enhance Earthquake and Tsunami Hazard Resiliency?

NASA Astrophysics Data System (ADS)

Olds, S. E.

2015-12-01

Creating a natural disaster-ready community requires interoperating scientific, technical, and social systems. In addition to the technical elements that need to be in place, communities and individuals need to be prepared to react when a natural hazard event occurs. Natural hazard awareness and preparedness training and education often takes place through informal learning at science centers and formal k-12 education programs as well as through awareness raising via strategically placed informational tsunami warning signs and placards. Museums and science centers are influential in raising science literacy within a community, however can science centers enhance earthquake and tsunami resiliency by providing hazard science content and preparedness exhibits? Museum docents and informal educators are uniquely situated within the community. They are transmitters and translators of science information to broad audiences. Through interaction with the public, docents are well positioned to be informants of the knowledge beliefs, and feelings of science center visitors. They themselves are life-long learners, both constantly learning from the museum content around them and sharing this content with visitors. They are also members of a community where they live. In-depth interviews with museum informal educators and docents were conducted at a science center in coastal Pacific Northwest. This region has a potential to be struck by a great 9+ Mw earthquake and subsequent tsunami. During the interviews, docents described how they applied learning from natural hazard exhibits at a science visitor center to their daily lives. During the individual interviews, the museum docents described their awareness (knowledge, attitudes, and behaviors) of natural hazards where they live and work, the feelings evoked as they learned about their hazard vulnerability, the extent to which they applied this learning and awareness to their lives, such as creating an evacuation plan, whether

Quantitative estimation of time-variable earthquake hazard by using fuzzy set theory

NASA Astrophysics Data System (ADS)

Deyi, Feng; Ichikawa, M.

1989-11-01

In this paper, the various methods of fuzzy set theory, called fuzzy mathematics, have been applied to the quantitative estimation of the time-variable earthquake hazard. The results obtained consist of the following. (1) Quantitative estimation of the earthquake hazard on the basis of seismicity data. By using some methods of fuzzy mathematics, seismicity patterns before large earthquakes can be studied more clearly and more quantitatively, highly active periods in a given region and quiet periods of seismic activity before large earthquakes can be recognized, similarities in temporal variation of seismic activity and seismic gaps can be examined and, on the other hand, the time-variable earthquake hazard can be assessed directly on the basis of a series of statistical indices of seismicity. Two methods of fuzzy clustering analysis, the method of fuzzy similarity, and the direct method of fuzzy pattern recognition, have been studied is particular. One method of fuzzy clustering analysis is based on fuzzy netting, and another is based on the fuzzy equivalent relation. (2) Quantitative estimation of the earthquake hazard on the basis of observational data for different precursors. The direct method of fuzzy pattern recognition has been applied to research on earthquake precursors of different kinds. On the basis of the temporal and spatial characteristics of recognized precursors, earthquake hazards in different terms can be estimated. This paper mainly deals with medium-short-term precursors observed in Japan and China.

Earthquake Hazard and the Environmental Seismic Intensity (ESI) Scale

NASA Astrophysics Data System (ADS)

Serva, Leonello; Vittori, Eutizio; Comerci, Valerio; Esposito, Eliana; Guerrieri, Luca; Michetti, Alessandro Maria; Mohammadioun, Bagher; Mohammadioun, Georgianna C.; Porfido, Sabina; Tatevossian, Ruben E.

2016-05-01

The main objective of this paper was to introduce the Environmental Seismic Intensity scale (ESI), a new scale developed and tested by an interdisciplinary group of scientists (geologists, geophysicists and seismologists) in the frame of the International Union for Quaternary Research (INQUA) activities, to the widest community of earth scientists and engineers dealing with seismic hazard assessment. This scale defines earthquake intensity by taking into consideration the occurrence, size and areal distribution of earthquake environmental effects (EEE), including surface faulting, tectonic uplift and subsidence, landslides, rock falls, liquefaction, ground collapse and tsunami waves. Indeed, EEEs can significantly improve the evaluation of seismic intensity, which still remains a critical parameter for a realistic seismic hazard assessment, allowing to compare historical and modern earthquakes. Moreover, as shown by recent moderate to large earthquakes, geological effects often cause severe damage"; therefore, their consideration in the earthquake risk scenario is crucial for all stakeholders, especially urban planners, geotechnical and structural engineers, hazard analysts, civil protection agencies and insurance companies. The paper describes background and construction principles of the scale and presents some case studies in different continents and tectonic settings to illustrate its relevant benefits. ESI is normally used together with traditional intensity scales, which, unfortunately, tend to saturate in the highest degrees. In this case and in unpopulated areas, ESI offers a unique way for assessing a reliable earthquake intensity. Finally, yet importantly, the ESI scale also provides a very convenient guideline for the survey of EEEs in earthquake-stricken areas, ensuring they are catalogued in a complete and homogeneous manner.

SEISRISK II; a computer program for seismic hazard estimation

USGS Publications Warehouse

Bender, Bernice; Perkins, D.M.

1982-01-01

The computer program SEISRISK II calculates probabilistic ground motion values for use in seismic hazard mapping. SEISRISK II employs a model that allows earthquakes to occur as points within source zones and as finite-length ruptures along faults. It assumes that earthquake occurrences have a Poisson distribution, that occurrence rates remain constant during the time period considered, that ground motion resulting from an earthquake is a known function of magnitude and distance, that seismically homogeneous source zones are defined, that fault locations are known, that fault rupture lengths depend on magnitude, and that earthquake rates as a function of magnitude are specified for each source. SEISRISK II calculates for each site on a grid of sites the level of ground motion that has a specified probability of being exceeded during a given time period. The program was designed to process a large (essentially unlimited) number of sites and sources efficiently and has been used to produce regional and national maps of seismic hazard.}t is a substantial revision of an earlier program SEISRISK I, which has never been documented. SEISRISK II runs considerably [aster and gives more accurate results than the earlier program and in addition includes rupture length and acceleration variability which were not contained in the original version. We describe the model and how it is implemented in the computer program and provide a flowchart and listing of the code.

Two examples of earthquake- hazard reduction in southern California.

USGS Publications Warehouse

Kockelman, W.J.; Campbell, C.C.

1983-01-01

Because California is seismically active, planners and decisionmakers must try to anticipate earthquake hazards there and, where possible, to reduce the hazards. Geologic and seismologic information provides the basis for the necessary plans and actions. Two examples of how such information is used are presented. The first involves assessing the impact of a major earthquake on critical facilities in southern California, and the second involves strengthening or removing unsafe masonry buildings in the Los Angeles area. -from Authors

Seismic Hazard and Ground Motion Characterization at the Itoiz Dam (Northern Spain)

NASA Astrophysics Data System (ADS)

Rivas-Medina, A.; Santoyo, M. A.; Luzón, F.; Benito, B.; Gaspar-Escribano, J. M.; García-Jerez, A.

2012-08-01

This paper presents a new hazard-consistent ground motion characterization of the Itoiz dam site, located in Northern Spain. Firstly, we propose a methodology with different approximation levels to the expected ground motion at the dam site. Secondly, we apply this methodology taking into account the particular characteristics of the site and of the dam. Hazard calculations were performed following the Probabilistic Seismic Hazard Assessment method using a logic tree, which accounts for different seismic source zonings and different ground-motion attenuation relationships. The study was done in terms of peak ground acceleration and several spectral accelerations of periods coinciding with the fundamental vibration periods of the dam. In order to estimate these ground motions we consider two different dam conditions: when the dam is empty ( T = 0.1 s) and when it is filled with water to its maximum capacity ( T = 0.22 s). Additionally, seismic hazard analysis is done for two return periods: 975 years, related to the project earthquake, and 4,975 years, identified with an extreme event. Soil conditions were also taken into account at the site of the dam. Through the proposed methodology we deal with different forms of characterizing ground motion at the study site. In a first step, we obtain the uniform hazard response spectra for the two return periods. In a second step, a disaggregation analysis is done in order to obtain the controlling earthquakes that can affect the dam. Subsequently, we characterize the ground motion at the dam site in terms of specific response spectra for target motions defined by the expected values SA ( T) of T = 0.1 and 0.22 s for the return periods of 975 and 4,975 years, respectively. Finally, synthetic acceleration time histories for earthquake events matching the controlling parameters are generated using the discrete wave-number method and subsequently analyzed. Because of the short relative distances between the controlling

Composite Earthquake Catalog of the Yellow Sea for Seismic Hazard Studies

NASA Astrophysics Data System (ADS)

Kang, S. Y.; Kim, K. H.; LI, Z.; Hao, T.

2017-12-01

The Yellow Sea (a.k.a West Sea in Korea) is an epicontinental and semi-closed sea located between Korea and China. Recent earthquakes in the Yellow Sea including, but not limited to, the Seogyuckryulbi-do (1 April 2014, magnitude 5.1), Heuksan-do (21 April 2013, magnitude 4.9), Baekryung-do (18 May 2013, magnitude 4.9) earthquakes, and the earthquake swarm in the Boryung offshore region in 2013, remind us of the seismic hazards affecting east Asia. This series of earthquakes in the Yellow Sea raised numerous questions. Unfortunately, both governments have trouble in monitoring seismicity in the Yellow Sea because earthquakes occur beyond their seismic networks. For example, the epicenters of the magnitude 5.1 earthquake in the Seogyuckryulbi-do region in 2014 reported by the Korea Meteorological Administration and China Earthquake Administration differed by approximately 20 km. This illustrates the difficulty with seismic monitoring and locating earthquakes in the region, despite the huge effort made by both governments. Joint effort is required not only to overcome the limits posed by political boundaries and geographical location but also to study seismicity and the underground structures responsible. Although the well-established and developing seismic networks in Korea and China have provided unprecedented amount and quality of seismic data, high quality catalog is limited to the recent 10s of years, which is far from major earthquake cycle. It is also noticed the earthquake catalog from either country is biased to its own and cannot provide complete picture of seismicity in the Yellow Sea. In order to understand seismic hazard and tectonics in the Yellow Sea, a composite earthquake catalog has been developed. We gathered earthquake information during last 5,000 years from various sources. There are good reasons to believe that some listings account for same earthquake, but in different source parameters. We established criteria in order to provide consistent

Oregon Hazard Explorer for Lifelines Program (OHELP): A web-based geographic information system tool for assessing potential Cascadia earthquake hazard

NASA Astrophysics Data System (ADS)

Sharifi Mood, M.; Olsen, M. J.; Gillins, D. T.; Javadnejad, F.

2016-12-01

The Cascadia Subduction Zone (CSZ) has the ability to generate earthquake as powerful as 9 moment magnitude creating great amount of damage to structures and facilities in Oregon. Series of deterministic earthquake analysis are performed for M9.0, M8.7, M8.4 and M8.1 presenting persistent, long lasting shaking associated with other geological threats such as ground shaking, landslides, liquefaction-induced ground deformations, fault rupture vertical displacement, tsunamis, etc. These ground deformation endangers urban structures, foundations, bridges, roadways, pipelines and other lifelines. Lifeline providers in Oregon, including private and public practices responsible for transportation, electric and gas utilities, water and wastewater, fuel, airports, and harbors face an aging infrastructure that was built prior to a full understanding of this extreme seismic risk. As recently experienced in Chile and Japan, a three to five minutes long earthquake scenario, expected in Oregon, necessities a whole different method of risk mitigation for these major lifelines than those created for shorter shakings from crustal earthquakes. A web-based geographic information system tool is developed to fully assess the potential hazard from the multiple threats impending from Cascadia subduction zone earthquakes in the region. The purpose of this website is to provide easy access to the latest and best available hazard information over the web, including work completed in the recent Oregon Resilience Plan (ORP) (OSSPAC, 2013) and other work completed by the Department of Geology and Mineral Industries (DOGAMI) and the United States Geological Survey (USGS). As a result, this tool is designated for engineers, planners, geologists, and others who need this information to help make appropriate decisions despite the fact that this web-GIS tool only needs minimal knowledge of GIS to work with.

Increasing seismicity in the U. S. midcontinent: Implications for earthquake hazard

USGS Publications Warehouse

Ellsworth, William L.; Llenos, Andrea L.; McGarr, Arthur F.; Michael, Andrew J.; Rubinstein, Justin L.; Mueller, Charles S.; Petersen, Mark D.; Calais, Eric

2015-01-01

Earthquake activity in parts of the central United States has increased dramatically in recent years. The space-time distribution of the increased seismicity, as well as numerous published case studies, indicates that the increase is of anthropogenic origin, principally driven by injection of wastewater coproduced with oil and gas from tight formations. Enhanced oil recovery and long-term production also contribute to seismicity at a few locations. Preliminary hazard models indicate that areas experiencing the highest rate of earthquakes in 2014 have a short-term (one-year) hazard comparable to or higher than the hazard in the source region of tectonic earthquakes in the New Madrid and Charleston seismic zones.

Insights into earthquake hazard map performance from shaking history simulations

NASA Astrophysics Data System (ADS)

Stein, S.; Vanneste, K.; Camelbeeck, T.; Vleminckx, B.

2017-12-01

Why recent large earthquakes caused shaking stronger than predicted by earthquake hazard maps is under debate. This issue has two parts. Verification involves how well maps implement probabilistic seismic hazard analysis (PSHA) ("have we built the map right?"). Validation asks how well maps forecast shaking ("have we built the right map?"). We explore how well a map can ideally perform by simulating an area's shaking history and comparing "observed" shaking to that predicted by a map generated for the same parameters. The simulations yield shaking distributions whose mean is consistent with the map, but individual shaking histories show large scatter. Infrequent large earthquakes cause shaking much stronger than mapped, as observed. Hence, PSHA seems internally consistent and can be regarded as verified. Validation is harder because an earthquake history can yield shaking higher or lower than that predicted while being consistent with the hazard map. The scatter decreases for longer observation times because the largest earthquakes and resulting shaking are increasingly likely to have occurred. For the same reason, scatter is much less for the more active plate boundary than for a continental interior. For a continental interior, where the mapped hazard is low, even an M4 event produces exceedances at some sites. Larger earthquakes produce exceedances at more sites. Thus many exceedances result from small earthquakes, but infrequent large ones may cause very large exceedances. However, for a plate boundary, an M6 event produces exceedance at only a few sites, and an M7 produces them in a larger, but still relatively small, portion of the study area. As reality gives only one history, and a real map involves assumptions about more complicated source geometries and occurrence rates, which are unlikely to be exactly correct and thus will contribute additional scatter, it is hard to assess whether misfit between actual shaking and a map — notably higher

Large Historical Earthquakes and Tsunami Hazards in the Western Mediterranean: Source Characteristics and Modelling

NASA Astrophysics Data System (ADS)

Harbi, Assia; Meghraoui, Mustapha; Belabbes, Samir; Maouche, Said

2010-05-01

The western Mediterranean region was the site of numerous large earthquakes in the past. Most of these earthquakes are located at the East-West trending Africa-Eurasia plate boundary and along the coastline of North Africa. The most recent recorded tsunamigenic earthquake occurred in 2003 at Zemmouri-Boumerdes (Mw 6.8) and generated ~ 2-m-high tsunami wave. The destructive wave affected the Balearic Islands and Almeria in southern Spain and Carloforte in southern Sardinia (Italy). The earthquake provided a unique opportunity to gather instrumental records of seismic waves and tide gauges in the western Mediterranean. A database that includes a historical catalogue of main events, seismic sources and related fault parameters was prepared in order to assess the tsunami hazard of this region. In addition to the analysis of the 2003 records, we study the 1790 Oran and 1856 Jijel historical tsunamigenic earthquakes (Io = IX and X, respectively) that provide detailed observations on the heights and extension of past tsunamis and damage in coastal zones. We performed the modelling of wave propagation using NAMI-DANCE code and tested different fault sources from synthetic tide gauges. We observe that the characteristics of seismic sources control the size and directivity of tsunami wave propagation on both northern and southern coasts of the western Mediterranean.

Probabilistic Appraisal of Earthquake Hazard Parameters Deduced from a Bayesian Approach in the Northwest Frontier of the Himalayas

NASA Astrophysics Data System (ADS)

Yadav, R. B. S.; Tsapanos, T. M.; Bayrak, Yusuf; Koravos, G. Ch.

2013-03-01

A straightforward Bayesian statistic is applied in five broad seismogenic source zones of the northwest frontier of the Himalayas to estimate the earthquake hazard parameters (maximum regional magnitude M max, β value of G-R relationship and seismic activity rate or intensity λ). For this purpose, a reliable earthquake catalogue which is homogeneous for M W ≥ 5.0 and complete during the period 1900 to 2010 is compiled. The Hindukush-Pamir Himalaya zone has been further divided into two seismic zones of shallow ( h ≤ 70 km) and intermediate depth ( h > 70 km) according to the variation of seismicity with depth in the subduction zone. The estimated earthquake hazard parameters by Bayesian approach are more stable and reliable with low standard deviations than other approaches, but the technique is more time consuming. In this study, quantiles of functions of distributions of true and apparent magnitudes for future time intervals of 5, 10, 20, 50 and 100 years are calculated with confidence limits for probability levels of 50, 70 and 90 % in all seismogenic source zones. The zones of estimated M max greater than 8.0 are related to the Sulaiman-Kirthar ranges, Hindukush-Pamir Himalaya and Himalayan Frontal Thrusts belt; suggesting more seismically hazardous regions in the examined area. The lowest value of M max (6.44) has been calculated in Northern-Pakistan and Hazara syntaxis zone which have estimated lowest activity rate 0.0023 events/day as compared to other zones. The Himalayan Frontal Thrusts belt exhibits higher earthquake magnitude (8.01) in next 100-years with 90 % probability level as compared to other zones, which reveals that this zone is more vulnerable to occurrence of a great earthquake. The obtained results in this study are directly useful for the probabilistic seismic hazard assessment in the examined region of Himalaya.

Earthquake hazards on the cascadia subduction zone.

PubMed

Heaton, T H; Hartzell, S H

1987-04-10

Large subduction earthquakes on the Cascadia subduction zone pose a potential seismic hazard. Very young oceanic lithosphere (10 million years old) is being subducted beneath North America at a rate of approximately 4 centimeters per year. The Cascadia subduction zone shares many characteristics with subduction zones in southern Chile, southwestern Japan, and Colombia, where comparably young oceanic lithosphere is also subducting. Very large subduction earthquakes, ranging in energy magnitude (M(w)) between 8 and 9.5, have occurred along these other subduction zones. If the Cascadia subduction zone is also storing elastic energy, a sequence of several great earthquakes (M(w) 8) or a giant earthquake (M(w) 9) would be necessary to fill this 1200-kilometer gap. The nature of strong ground motions recorded during subduction earthquakes of M(w) less than 8.2 is discussed. Strong ground motions from even larger earthquakes (M(w) up to 9.5) are estimated by simple simulations. If large subduction earthquakes occur in the Pacific Northwest, relatively strong shaking can be expected over a large region. Such earthquakes may also be accompanied by large local tsunamis.

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

NASA Astrophysics Data System (ADS)

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.

International Collaboration for Strengthening Capacity to Assess Earthquake Hazard in Indonesia

NASA Astrophysics Data System (ADS)

Cummins, P. R.; Hidayati, S.; Suhardjono, S.; Meilano, I.; Natawidjaja, D.

2012-12-01

Indonesia has experienced a dramatic increase in earthquake risk due to rapid population growth in the 20th century, much of it occurring in areas near the subduction zone plate boundaries that are prone to earthquake occurrence. While recent seismic hazard assessments have resulted in better building codes that can inform safer building practices, many of the fundamental parameters controlling earthquake occurrence and ground shaking - e.g., fault slip rates, earthquake scaling relations, ground motion prediction equations, and site response - could still be better constrained. In recognition of the need to improve the level of information on which seismic hazard assessments are based, the Australian Agency for International Development (AusAID) and Indonesia's National Agency for Disaster Management (BNPB), through the Australia-Indonesia Facility for Disaster Reduction, have initiated a 4-year project designed to strengthen the Government of Indonesia's capacity to reliably assess earthquake hazard. This project is a collaboration of Australian institutions including Geoscience Australia and the Australian National University, with Indonesian government agencies and universities including the Agency for Meteorology, Climatology and Geophysics, the Geological Agency, the Indonesian Institute of Sciences, and Bandung Institute of Technology. Effective earthquake hazard assessment requires input from many different types of research, ranging from geological studies of active faults, seismological studies of crustal structure, earthquake sources and ground motion, PSHA methodology, and geodetic studies of crustal strain rates. The project is a large and diverse one that spans all these components, and these will be briefly reviewed in this presentation

The March 11, 2002 Masafi, United Arab Emirates Earthquake: Insights into the Seismotectonics of the Northern Oman Mountains

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rodgers, A; Fowler, A; Al-Amri, A

2005-04-26

A moderate (M{approx}5) earthquake struck the northeastern United Arab Emirates (UAE) and northern Oman on March 11, 2002. The event was felt over a wide area of the northern Emirates and was accompanied by smaller (felt) events before and after the March 11 main shock. The event was large enough to be detected and located by global networks at teleseismic distances. We estimated focal mechanism and depth from broadband complete regional waveform modeling. We report a normal mechanism with a slight right-lateral strike-slip component consistent with the large-scale tectonics. The normal component suggests relaxation of obducted crust of the Semailmore » Ophilite (specifically, the Khor Fakkan Block) while the right-lateral strike-slip component of the mechanism is consistent with shear across the Oman Line. Felt earthquakes are rare in the region, however no regional seismic network exists in the UAE to determine local seismicity. This event offers a unique opportunity to study the active tectonics of the region as well as inform future studies of seismic hazard in the UAE and northern Oman.« less

A stochastic automata network for earthquake simulation and hazard estimation

NASA Astrophysics Data System (ADS)

Belubekian, Maya Ernest

1998-11-01

This research develops a model for simulation of earthquakes on seismic faults with available earthquake catalog data. The model allows estimation of the seismic hazard at a site of interest and assessment of the potential damage and loss in a region. There are two approaches for studying the earthquakes: mechanistic and stochastic. In the mechanistic approach, seismic processes, such as changes in stress or slip on faults, are studied in detail. In the stochastic approach, earthquake occurrences are simulated as realizations of a certain stochastic process. In this dissertation, a stochastic earthquake occurrence model is developed that uses the results from dislocation theory for the estimation of slip released in earthquakes. The slip accumulation and release laws and the event scheduling mechanism adopted in the model result in a memoryless Poisson process for the small and moderate events and in a time- and space-dependent process for large events. The minimum and maximum of the hazard are estimated by the model when the initial conditions along the faults correspond to a situation right after a largest event and after a long seismic gap, respectively. These estimates are compared with the ones obtained from a Poisson model. The Poisson model overestimates the hazard after the maximum event and underestimates it in the period of a long seismic quiescence. The earthquake occurrence model is formulated as a stochastic automata network. Each fault is divided into cells, or automata, that interact by means of information exchange. The model uses a statistical method called bootstrap for the evaluation of the confidence bounds on its results. The parameters of the model are adjusted to the target magnitude patterns obtained from the catalog. A case study is presented for the city of Palo Alto, where the hazard is controlled by the San Andreas, Hayward and Calaveras faults. The results of the model are used to evaluate the damage and loss distribution in Palo Alto

Central US earthquake catalog for hazard maps of Memphis, Tennessee

USGS Publications Warehouse

Wheeler, R.L.; Mueller, C.S.

2001-01-01

An updated version of the catalog that was used for the current national probabilistic seismic-hazard maps would suffice for production of large-scale hazard maps of the Memphis urban area. Deaggregation maps provide guidance as to the area that a catalog for calculating Memphis hazard should cover. For the future, the Nuttli and local network catalogs could be examined for earthquakes not presently included in the catalog. Additional work on aftershock removal might reduce hazard uncertainty. Graphs of decadal and annual earthquake rates suggest completeness at and above magnitude 3 for the last three or four decades. Any additional work on completeness should consider the effects of rapid, local population changes during the Nation's westward expansion. ?? 2001 Elsevier Science B.V. All rights reserved.

Earthquake hazards in the Alaska transportation corridors

DOT National Transportation Integrated Search

1983-03-01

Based on observations made by modern seismographic networks since 1967, and taking into consideration historical records of large Alaskan earthquakes in the past, it is judged that the hazards faced by transportation corridors in different areas of t...

Seismic hazard assessment over time: Modelling earthquakes in Taiwan

NASA Astrophysics Data System (ADS)

Chan, Chung-Han; Wang, Yu; Wang, Yu-Ju; Lee, Ya-Ting

2017-04-01

To assess the seismic hazard with temporal change in Taiwan, we develop a new approach, combining both the Brownian Passage Time (BPT) model and the Coulomb stress change, and implement the seismogenic source parameters by the Taiwan Earthquake Model (TEM). The BPT model was adopted to describe the rupture recurrence intervals of the specific fault sources, together with the time elapsed since the last fault-rupture to derive their long-term rupture probability. We also evaluate the short-term seismicity rate change based on the static Coulomb stress interaction between seismogenic sources. By considering above time-dependent factors, our new combined model suggests an increased long-term seismic hazard in the vicinity of active faults along the western Coastal Plain and the Longitudinal Valley, where active faults have short recurrence intervals and long elapsed time since their last ruptures, and/or short-term elevated hazard levels right after the occurrence of large earthquakes due to the stress triggering effect. The stress enhanced by the February 6th, 2016, Meinong ML 6.6 earthquake also significantly increased rupture probabilities of several neighbouring seismogenic sources in Southwestern Taiwan and raised hazard level in the near future. Our approach draws on the advantage of incorporating long- and short-term models, to provide time-dependent earthquake probability constraints. Our time-dependent model considers more detailed information than any other published models. It thus offers decision-makers and public officials an adequate basis for rapid evaluations of and response to future emergency scenarios such as victim relocation and sheltering.

Probabilistic liquefaction hazard analysis at liquefied sites of 1956 Dunaharaszti earthquake, in Hungary

NASA Astrophysics Data System (ADS)

Győri, Erzsébet; Gráczer, Zoltán; Tóth, László; Bán, Zoltán; Horváth, Tibor

2017-04-01

Liquefaction potential evaluations are generally made to assess the hazard from specific scenario earthquakes. These evaluations may estimate the potential in a binary fashion (yes/no), define a factor of safety or predict the probability of liquefaction given a scenario event. Usually the level of ground shaking is obtained from the results of PSHA. Although it is determined probabilistically, a single level of ground shaking is selected and used within the liquefaction potential evaluation. In contrary, the fully probabilistic liquefaction potential assessment methods provide a complete picture of liquefaction hazard, namely taking into account the joint probability distribution of PGA and magnitude of earthquake scenarios; both of which are key inputs in the stress-based simplified methods. Kramer and Mayfield (2007) has developed a fully probabilistic liquefaction potential evaluation method using a performance-based earthquake engineering (PBEE) framework. The results of the procedure are the direct estimate of the return period of liquefaction and the liquefaction hazard curves in function of depth. The method combines the disaggregation matrices computed for different exceedance frequencies during probabilistic seismic hazard analysis with one of the recent models for the conditional probability of liquefaction. We have developed a software for the assessment of performance-based liquefaction triggering on the basis of Kramer and Mayfield method. Originally the SPT based probabilistic method of Cetin et al. (2004) was built-in into the procedure of Kramer and Mayfield to compute the conditional probability however there is no professional consensus about its applicability. Therefore we have included not only Cetin's method but Idriss and Boulanger (2012) SPT based moreover Boulanger and Idriss (2014) CPT based procedures into our computer program. In 1956, a damaging earthquake of magnitude 5.6 occurred in Dunaharaszti, in Hungary. Its epicenter was located

Integrating Real-time Earthquakes into Natural Hazard Courses

NASA Astrophysics Data System (ADS)

Furlong, K. P.; Benz, H. M.; Whitlock, J. S.; Bittenbinder, A. N.; Bogaert, B. B.

2001-12-01

Natural hazard courses are playing an increasingly important role in college and university earth science curricula. Students' intrinsic curiosity about the subject and the potential to make the course relevant to the interests of both science and non-science students make natural hazards courses popular additions to a department's offerings. However, one vital aspect of "real-life" natural hazard management that has not translated well into the classroom is the real-time nature of both events and response. The lack of a way to entrain students into the event/response mode has made implementing such real-time activities into classroom activities problematic. Although a variety of web sites provide near real-time postings of natural hazards, students essentially learn of the event after the fact. This is particularly true for earthquakes and other events with few precursors. As a result, the "time factor" and personal responsibility associated with natural hazard response is lost to the students. We have integrated the real-time aspects of earthquake response into two natural hazard courses at Penn State (a 'general education' course for non-science majors, and an upper-level course for science majors) by implementing a modification of the USGS Earthworm system. The Earthworm Database Management System (E-DBMS) catalogs current global seismic activity. It provides earthquake professionals with real-time email/cell phone alerts of global seismic activity and access to the data for review/revision purposes. We have modified this system so that real-time response can be used to address specific scientific, policy, and social questions in our classes. As a prototype of using the E-DBMS in courses, we have established an Earthworm server at Penn State. This server receives national and global seismic network data and, in turn, transmits the tailored alerts to "on-duty" students (e-mail, pager/cell phone notification). These students are responsible to react to the alarm

Long aftershock sequences within continents and implications for earthquake hazard assessment.

PubMed

Stein, Seth; Liu, Mian

2009-11-05

One of the most powerful features of plate tectonics is that the known plate motions give insight into both the locations and average recurrence interval of future large earthquakes on plate boundaries. Plate tectonics gives no insight, however, into where and when earthquakes will occur within plates, because the interiors of ideal plates should not deform. As a result, within plate interiors, assessments of earthquake hazards rely heavily on the assumption that the locations of small earthquakes shown by the short historical record reflect continuing deformation that will cause future large earthquakes. Here, however, we show that many of these recent earthquakes are probably aftershocks of large earthquakes that occurred hundreds of years ago. We present a simple model predicting that the length of aftershock sequences varies inversely with the rate at which faults are loaded. Aftershock sequences within the slowly deforming continents are predicted to be significantly longer than the decade typically observed at rapidly loaded plate boundaries. These predictions are in accord with observations. So the common practice of treating continental earthquakes as steady-state seismicity overestimates the hazard in presently active areas and underestimates it elsewhere.

Probabilities of Earthquake Occurrences along the Sumatra-Andaman Subduction Zone

NASA Astrophysics Data System (ADS)

Pailoplee, Santi

2017-03-01

Earthquake activities along the Sumatra-Andaman Subduction Zone (SASZ) were clarified using the derived frequency-magnitude distribution in terms of the (i) most probable maximum magnitudes, (ii) return periods and (iii) probabilities of earthquake occurrences. The northern segment of SASZ, along the western coast of Myanmar to southern Nicobar, was found to be capable of generating an earthquake of magnitude 6.1-6.4 Mw in the next 30-50 years, whilst the southern segment of offshore of the northwestern and western parts of Sumatra (defined as a high hazard region) had a short recurrence interval of 6-12 and 10-30 years for a 6.0 and 7.0 Mw magnitude earthquake, respectively, compared to the other regions. Throughout the area along the SASZ, there are 70- almost 100% probabilities of the earthquake with Mw up to 6.0 might be generated in the next 50 years whilst the northern segment had less than 50% chance of occurrence of a 7.0 Mw earthquake in the next 50 year. Although Rangoon was defined as the lowest hazard among the major city in the vicinity of SASZ, there is 90% chance of a 6.0 Mw earthquake in the next 50 years. Therefore, the effective mitigation plan of seismic hazard should be contributed.

Cascading hazards: Understanding triggering relations between wet tropical cyclones, landslides, and earthquakes

NASA Astrophysics Data System (ADS)

Wdowinski, S.; Peng, Z.; Ferrier, K.; Lin, C. H.; Hsu, Y. J.; Shyu, J. B. H.

2017-12-01

Earthquakes, landslides, and tropical cyclones are extreme hazards that pose significant threats to human life and property. Some of the couplings between these hazards are well known. For example, sudden, widespread landsliding can be triggered by large earthquakes and by extreme rainfall events like tropical cyclones. Recent studies have also shown that earthquakes can be triggered by erosional unloading over 100-year timescales. In a NASA supported project, titled "Cascading hazards: Understanding triggering relations between wet tropical cyclones, landslides, and earthquake", we study triggering relations between these hazard types. The project focuses on such triggering relations in Taiwan, which is subjected to very wet tropical storms, landslides, and earthquakes. One example for such triggering relations is the 2009 Morakot typhoon, which was the wettest recorded typhoon in Taiwan (2850 mm of rain in 100 hours). The typhoon caused widespread flooding and triggered more than 20,000 landslides, including the devastating Hsiaolin landslide. Six months later, the same area was hit by the 2010 M=6.4 Jiashian earthquake near Kaohsiung city, which added to the infrastructure damage induced by the typhoon and the landslides. Preliminary analysis of temporal relations between main-shock earthquakes and the six wettest typhoons in Taiwan's past 50 years reveals similar temporal relations between M≥5 events and wet typhoons. Future work in the project will include remote sensing analysis of landsliding, seismic and geodetic monitoring of landslides, detection of microseismicity and tremor activities, and mechanical modeling of crustal stress changes due to surface unloading.

The wicked problem of earthquake hazard in developing countries: the example of Bangladesh

NASA Astrophysics Data System (ADS)

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

2017-12-01

Many developing nations in earthquake-prone areas confront a tough problem: how much of their limited resources to use mitigating earthquake hazards? This decision is difficult because it is unclear when an infrequent major earthquake may happen, how big it could be, and how much harm it may cause. This issue faces nations with profound immediate needs and ongoing rapid urbanization. Earthquake hazard mitigation in Bangladesh is a wicked problem. It is the world's most densely populated nation, with 160 million people in an area the size of Iowa. Complex geology and sparse data make assessing a possibly-large earthquake hazard difficult. Hence it is hard to decide how much of the limited resources available should be used for earthquake hazard mitigation, given other more immediate needs. Per capita GDP is $1200, so Bangladesh is committed to economic growth and resources are needed to address many critical challenges and hazards. In their subtropical environment, rural Bangladeshis traditionally relied on modest mud or bamboo homes. Their rapidly growing, crowded capital, Dhaka, is filled with multistory concrete buildings likely to be vulnerable to earthquakes. The risk is compounded by the potential collapse of services and accessibility after a major temblor. However, extensive construction as the population shifts from rural to urban provides opportunity for earthquake-risk reduction. While this situation seems daunting, it is not hopeless. Robust risk management is practical, even for developing nations. It involves recognizing uncertainties and developing policies that should give a reasonable outcome for a range of the possible hazard and loss scenarios. Over decades, Bangladesh has achieved a thousandfold reduction in risk from tropical cyclones by building shelters and setting up a warning system. Similar efforts are underway for earthquakes. Smart investments can be very effective, even if modest. Hence, we suggest strategies consistent with high

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

NASA Astrophysics Data System (ADS)

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.

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

USGS Publications Warehouse

McNamara, Daniel E.; Yeck, William; Barnhart, William D.; Schulte-Pelkum, V.; Bergman, E.; Adhikari, L. B.; Dixit, Amod; Hough, S.E.; Benz, Harley M.; Earle, Paul

2017-01-01

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.

The fujairah united arab emirates (uae) (ml = 5.1) earthquake of march 11, 2002 a reminder for the immediate need to develop and implement a national hazard mitigation strategy

NASA Astrophysics Data System (ADS)

Al-Homoud, A.

2003-04-01

On March 11, 2002, at mid nigh, the Fujairah Masafi region in the UAE was shaken by an earthquake of shallow depth and local magnitude m = 5.1 on Richter Scale. The earthquake occurred on Dibba fault in the UAE with epicenter of the earthquake at 20 km NW of Fujairha city. The focal depth was just 10 km. The earthquake was felt in most parts of the northern emirates: Dubai, Sharjah, Ajman, Ras Al-Khaima, and Um-Qwain. The "main shock" was followed in the following weeks by more than twenty five earthquakes with local magnitude ranging from m = 4 to m = 4.8. The location of those earthquakes was along Zagros Reverse Faulting System in the Iranian side the Arabian Gulf, opposite to the Shores of the UAE. Most of these earthquakes were shallow too and were actually felt by the people. However, there was another strong earthquake in early April 2002 in the same Masafi region with local magnitude m = 5.1 and focal depth 30 km, therefore it was not felt by the northern emirates residents. No major structural damages to buildings and lifeline systems were reported in the several cities located in the vicinity of the earthquake epicenter. The very small values of ground accelerations were not enough to test the structural integrity of tall building and major infrastructures. Future major earthquakes anticipated in the region in close vicinity of northern emirates, once they occur, and considering the noticeable local site effect of the emirates sandy soils of high water table levels, will surely put these newly constructed building into the real test. Even though there were no casualties in the March 11th event, but there was major fear as a result of the loud sound of rock rupture heard in the mountains close to Maafi, the noticeable disturbance of animals and birds minutes before the earthquake incident and during the incident, cracks in the a good number of Masafi buildings and major damages that occurred in "old" buildings of Fujairah Masafi area, the closest city to

Loss Estimations due to Earthquakes and Secondary Technological Hazards

NASA Astrophysics Data System (ADS)

Frolova, N.; Larionov, V.; Bonnin, J.

2009-04-01

Expected loss and damage assessment due to natural and technological disasters are of primary importance for emergency management just after the disaster, as well as for development and implementation of preventive measures plans. The paper addresses the procedures and simulation models for loss estimations due to strong earthquakes and secondary technological accidents. The mathematical models for shaking intensity distribution, damage to buildings and structures, debris volume, number of fatalities and injuries due to earthquakes and technological accidents at fire and chemical hazardous facilities are considered, which are used in geographical information systems assigned for these purposes. The criteria of technological accidents occurrence are developed on the basis of engineering analysis of past events' consequences. The paper is providing the results of scenario earthquakes consequences estimation and individual seismic risk assessment taking into account the secondary technological hazards at regional and urban levels. The individual risk is understood as the probability of death (or injuries) due to possible hazardous event within one year in a given territory. It is determined through mathematical expectation of social losses taking into account the number of inhabitants in the considered settlement and probability of natural and/or technological disaster.

Earthquake Hazard Assessment: Basics of Evaluation

NASA Astrophysics Data System (ADS)

Kossobokov, Vladimir

2016-04-01

Seismic hazard assessment (SHA) is not an easy task that implies a delicate application of statistics to data of limited size and different accuracy. Earthquakes follow the Unified Scaling Law that generalizes the Gutenberg-Richter relationship by taking into account naturally fractal distribution of their sources. Moreover, earthquakes, including the great and mega events, are clustered in time and their sequences have irregular recurrence intervals. Furthermore, earthquake related observations are limited to the recent most decades (or centuries in just a few rare cases). Evidently, all this complicates reliable assessment of seismic hazard and associated risks. Making SHA claims, either termless or time dependent (so-called t-DASH), quantitatively probabilistic in the frames of the most popular objectivists' viewpoint on probability requires a long series of "yes/no" trials, which cannot be obtained without an extended rigorous testing of the method predictions against real observations. Therefore, we reiterate the necessity and possibility of applying the modified tools of Earthquake Prediction Strategies, in particular, the Error Diagram, introduced by G.M. Molchan in early 1990ies for evaluation of SHA, and the Seismic Roulette null-hypothesis as a measure of the alerted space. The set of errors, i.e. the rates of failure and of the alerted space-time volume, compared to those obtained in the same number of random guess trials permits evaluating the SHA method effectiveness and determining the optimal choice of the parameters in regard to specified cost-benefit functions. These and other information obtained in such a testing supplies us with a realistic estimate of confidence in SHA results and related recommendations on the level of risks for decision making in regard to engineering design, insurance, and emergency management. These basics of SHA evaluation are exemplified in brief with a few examples, which analyses in more detail are given in a poster of

Preliminary Earthquake Hazard Map of Afghanistan

USGS Publications Warehouse

Boyd, Oliver S.; Mueller, Charles S.; Rukstales, Kenneth S.

2007-01-01

Introduction Earthquakes represent a serious threat to the people and institutions of Afghanistan. As part of a United States Agency for International Development (USAID) effort to assess the resource potential and seismic hazards of Afghanistan, the Seismic Hazard Mapping group of the United States Geological Survey (USGS) has prepared a series of probabilistic seismic hazard maps that help quantify the expected frequency and strength of ground shaking nationwide. To construct the maps, we do a complete hazard analysis for each of ~35,000 sites in the study area. We use a probabilistic methodology that accounts for all potential seismic sources and their rates of earthquake activity, and we incorporate modeling uncertainty by using logic trees for source and ground-motion parameters. See the Appendix for an explanation of probabilistic seismic hazard analysis and discussion of seismic risk. Afghanistan occupies a southward-projecting, relatively stable promontory of the Eurasian tectonic plate (Ambraseys and Bilham, 2003; Wheeler and others, 2005). Active plate boundaries, however, surround Afghanistan on the west, south, and east. To the west, the Arabian plate moves northward relative to Eurasia at about 3 cm/yr. The active plate boundary trends northwestward through the Zagros region of southwestern Iran. Deformation is accommodated throughout the territory of Iran; major structures include several north-south-trending, right-lateral strike-slip fault systems in the east and, farther to the north, a series of east-west-trending reverse- and strike-slip faults. This deformation apparently does not cross the border into relatively stable western Afghanistan. In the east, the Indian plate moves northward relative to Eurasia at a rate of about 4 cm/yr. A broad, transpressional plate-boundary zone extends into eastern Afghanistan, trending southwestward from the Hindu Kush in northeast Afghanistan, through Kabul, and along the Afghanistan-Pakistan border

Probabilistic Seismic Hazard Assessment for Himalayan-Tibetan Region from Historical and Instrumental Earthquake Catalogs

NASA Astrophysics Data System (ADS)

Rahman, M. Moklesur; Bai, Ling; Khan, Nangyal Ghani; Li, Guohui

2018-02-01

The Himalayan-Tibetan region has a long history of devastating earthquakes with wide-spread casualties and socio-economic damages. Here, we conduct the probabilistic seismic hazard analysis by incorporating the incomplete historical earthquake records along with the instrumental earthquake catalogs for the Himalayan-Tibetan region. Historical earthquake records back to more than 1000 years ago and an updated, homogenized and declustered instrumental earthquake catalog since 1906 are utilized. The essential seismicity parameters, namely, the mean seismicity rate γ, the Gutenberg-Richter b value, and the maximum expected magnitude M max are estimated using the maximum likelihood algorithm assuming the incompleteness of the catalog. To compute the hazard value, three seismogenic source models (smoothed gridded, linear, and areal sources) and two sets of ground motion prediction equations are combined by means of a logic tree on accounting the epistemic uncertainties. The peak ground acceleration (PGA) and spectral acceleration (SA) at 0.2 and 1.0 s are predicted for 2 and 10% probabilities of exceedance over 50 years assuming bedrock condition. The resulting PGA and SA maps show a significant spatio-temporal variation in the hazard values. In general, hazard value is found to be much higher than the previous studies for regions, where great earthquakes have actually occurred. The use of the historical and instrumental earthquake catalogs in combination of multiple seismogenic source models provides better seismic hazard constraints for the Himalayan-Tibetan region.

Earthquake Hazard and Risk Assessment based on Unified Scaling Law for Earthquakes: Altai-Sayan Region

NASA Astrophysics Data System (ADS)

Kossobokov, V. G.; Nekrasova, A.

2017-12-01

We continue applying the general concept of seismic risk analysis in a number of seismic regions worldwide by constructing regional seismic hazard maps based on morphostructural analysis, pattern recognition, and the Unified Scaling Law for Earthquakes, USLE, which generalizes the Gutenberg-Richter relationship making use of naturally fractal distribution of earthquake sources of different size in a seismic region. The USLE stands for an empirical relationship log10N(M, L) = A + B·(5 - M) + C·log10L, where N(M, L) is the expected annual number of earthquakes of a certain magnitude M within an seismically prone area of linear dimension L. We use parameters A, B, and C of USLE to estimate, first, the expected maximum credible magnitude in a time interval at seismically prone nodes of the morphostructural scheme of the region under study, then map the corresponding expected ground shaking parameters (e.g. peak ground acceleration, PGA, or macro-seismic intensity etc.). After a rigorous testing against the available seismic evidences in the past (usually, the observed instrumental PGA or the historically reported macro-seismic intensity), such a seismic hazard map is used to generate maps of specific earthquake risks for population, cities, and infrastructures (e.g., those based on census of population, buildings inventory, etc.). This, USLE based, methodology of seismic hazard and risks assessment is applied to the territory of Altai-Sayan Region, of Russia. The study supported by the Russian Science Foundation Grant No. 15-17-30020.

Next-Level ShakeZoning for Earthquake Hazard Definition in Nevada

NASA Astrophysics Data System (ADS)

Louie, J. N.; Savran, W. H.; Flinchum, B. A.; Dudley, C.; Prina, N.; Pullammanappallil, S.; Pancha, A.

2011-12-01

We are developing "Next-Level ShakeZoning" procedures tailored for defining earthquake hazards in Nevada. The current Federally sponsored tools- the USGS hazard maps and ShakeMap, and FEMA HAZUS- were developed as statistical summaries to match earthquake data from California, Japan, and Taiwan. The 2008 Wells and Mogul events in Nevada showed in particular that the generalized statistical approach taken by ShakeMap cannot match actual data on shaking from earthquakes in the Intermountain West, even to first order. Next-Level ShakeZoning relies on physics and geology to define earthquake shaking hazards, rather than statistics. It follows theoretical and computational developments made over the past 20 years, to capitalize on detailed and specific local data sets to more accurately model the propagation and amplification of earthquake waves through the multiple geologic basins of the Intermountain West. Excellent new data sets are now available for Las Vegas Valley. Clark County, Nevada has completed the nation's very first effort to map earthquake hazard class systematically through an entire urban area using Optim's SeisOpt° ReMi technique, which was adapted for large-scale data collection. Using the new Parcel Map in computing shaking in the Valley for scenario earthquakes is crucial for obtaining realistic predictions of ground motions. In an educational element of the project, a dozen undergraduate students have been computing 50 separate earthquake scenarios affecting Las Vegas Valley, using the Next-Level ShakeZoning process. Despite affecting only the upper 30 meters, the Vs30 geotechnical shear-velocity from the Parcel Map shows clear effects on 3-d shaking predictions computed so far at frequencies from 0.1 Hz up to 1.0 Hz. The effect of the Parcel Map on even the 0.1-Hz waves is prominent even with the large mismatch of wavelength to geotechnical depths. Amplifications and de-amplifications affected by the Parcel Map exceed a factor of two, and are

Predicting earthquake effects—Learning from Northridge and Loma Prieta

USGS Publications Warehouse

Holzer, Thomas L.

1994-01-01

The continental United States has been rocked by two particularly damaging earthquakes in the last 4.5 years, Loma Prieta in northern California in 1989 and Northridge in southern California in 1994. Combined losses from these two earthquakes approached $30 billion. Approximately half these losses were reimbursed by the federal government. Because large earthquakes typically overwhelm state resources and place unplanned burdens on the federal government, it is important to learn from these earthquakes how to reduce future losses. My purpose here is to explore a potential implication of the Northridge and Loma Prieta earthquakes for hazard-mitigation strategies: earth scientists should increase their efforts to map hazardous areas within urban regions. 

Scenario earthquake hazards for the Long Valley Caldera-Mono Lake area, east-central California (ver. 2.0, January 2018)

USGS Publications Warehouse

Chen, Rui; Branum, David M.; Wills, Chris J.; Hill, David P.

2014-06-30

As part of the U.S. Geological Survey’s (USGS) multi-hazards project in the Long Valley Caldera-Mono Lake area, the California Geological Survey (CGS) developed several earthquake scenarios and evaluated potential seismic hazards, including ground shaking, surface fault rupture, liquefaction, and landslide hazards associated with these earthquake scenarios. The results of these analyses can be useful in estimating the extent of potential damage and economic losses because of potential earthquakes and also for preparing emergency response plans.The Long Valley Caldera-Mono Lake area has numerous active faults. Five of these faults or fault zones are considered capable of producing magnitude ≥6.7 earthquakes according to the Uniform California Earthquake Rupture Forecast, Version 2 (UCERF 2) developed by the 2007 Working Group on California Earthquake Probabilities (WGCEP) and the USGS National Seismic Hazard Mapping Program. These five faults are the Fish Slough, Hartley Springs, Hilton Creek, Mono Lake, and Round Valley Faults. CGS developed earthquake scenarios for these five faults in the study area and for the White Mountains Fault Zone to the east of the study area.In this report, an earthquake scenario is intended to depict the potential consequences of significant earthquakes. A scenario earthquake is not necessarily the largest or most damaging earthquake possible on a recognized fault. Rather it is both large enough and likely enough that emergency planners should consider it in regional emergency response plans. In particular, the ground motion predicted for a given scenario earthquake does not represent a full probabilistic hazard assessment, and thus it does not provide the basis for hazard zoning and earthquake-resistant building design.Earthquake scenarios presented here are based on fault geometry and activity data developed by the WGCEP, and are consistent with the 2008 Update of the United States National Seismic Hazard Maps (NSHM). Alternatives

Earthquake hazard and risk assessment based on Unified Scaling Law for Earthquakes: Greater Caucasus and Crimea

NASA Astrophysics Data System (ADS)

Kossobokov, Vladimir G.; Nekrasova, Anastasia K.

2018-05-01

We continue applying the general concept of seismic risk analysis in a number of seismic regions worldwide by constructing regional seismic hazard maps based on morphostructural analysis, pattern recognition, and the Unified Scaling Law for Earthquakes (USLE), which generalizes the Gutenberg-Richter relationship making use of naturally fractal distribution of earthquake sources of different size in a seismic region. The USLE stands for an empirical relationship log10 N(M, L) = A + B·(5 - M) + C·log10 L, where N(M, L) is the expected annual number of earthquakes of a certain magnitude M within a seismically prone area of linear dimension L. We use parameters A, B, and C of USLE to estimate, first, the expected maximum magnitude in a time interval at seismically prone nodes of the morphostructural scheme of the region under study, then map the corresponding expected ground shaking parameters (e.g., peak ground acceleration, PGA, or macro-seismic intensity). After a rigorous verification against the available seismic evidences in the past (usually, the observed instrumental PGA or the historically reported macro-seismic intensity), such a seismic hazard map is used to generate maps of specific earthquake risks for population, cities, and infrastructures (e.g., those based on census of population, buildings inventory). The methodology of seismic hazard and risk assessment is illustrated by application to the territory of Greater Caucasus and Crimea.

Seismic Landslide Hazard for the Cities of Oakland and Piedmont, California

USGS Publications Warehouse

Miles, Scott B.; Keefer, David K.

2001-01-01

This map describes the possible hazard from earthquake-induced landslides for the cities of Oakland and Piedmont, CA. The hazard depicted by this map was modeled for a scenario corresponding to an M=7.1 earthquake on the Hayward, CA fault. This scenario magnitude is associated with complete rupture of the northern and southern segments of the Hayward fault, an event that has an estimated return period of about 500 years. The modeled hazard also corresponds to completely saturated ground-water conditions resulting from an extreme storm event or series of storm events. This combination of earthquake and ground-water scenarios represents a particularly severe state of hazard for earthquake-induced landslides. For dry ground-water conditions, overall hazard will be less, while relative patterns of hazard are likely to change.

Development of optimization-based probabilistic earthquake scenarios for the city of Tehran

NASA Astrophysics Data System (ADS)

Zolfaghari, M. R.; Peyghaleh, E.

2016-01-01

This paper presents the methodology and practical example for the application of optimization process to select earthquake scenarios which best represent probabilistic earthquake hazard in a given region. The method is based on simulation of a large dataset of potential earthquakes, representing the long-term seismotectonic characteristics in a given region. The simulation process uses Monte-Carlo simulation and regional seismogenic source parameters to generate a synthetic earthquake catalogue consisting of a large number of earthquakes, each characterized with magnitude, location, focal depth and fault characteristics. Such catalogue provides full distributions of events in time, space and size; however, demands large computation power when is used for risk assessment, particularly when other sources of uncertainties are involved in the process. To reduce the number of selected earthquake scenarios, a mixed-integer linear program formulation is developed in this study. This approach results in reduced set of optimization-based probabilistic earthquake scenario, while maintaining shape of hazard curves and full probabilistic picture by minimizing the error between hazard curves driven by full and reduced sets of synthetic earthquake scenarios. To test the model, the regional seismotectonic and seismogenic characteristics of northern Iran are used to simulate a set of 10,000-year worth of events consisting of some 84,000 earthquakes. The optimization model is then performed multiple times with various input data, taking into account probabilistic seismic hazard for Tehran city as the main constrains. The sensitivity of the selected scenarios to the user-specified site/return period error-weight is also assessed. The methodology could enhance run time process for full probabilistic earthquake studies like seismic hazard and risk assessment. The reduced set is the representative of the contributions of all possible earthquakes; however, it requires far less

The 2012 Emilia (Northern Italy) earthquake sequence: an attempt of historical reading

NASA Astrophysics Data System (ADS)

Graziani, L.; Bernardini, F.; Castellano, C.; Del Mese, S.; Ercolani, E.; Rossi, A.; Tertulliani, A.; Vecchi, M.

2015-04-01

In May-June 2012, the Po Valley (Northern Italy) was struck by an earthquake sequence whose strongest event occurred on 20 May (Mw 5.9). The intensity values (Imax 7-8 EMS98) assessed through macroseismic field surveys seemed inappropriate to describe the whole range of effects observed, especially those to monumental heritage, which suffered very heavy damage and destruction. The observed intensities in fact were significantly lower than those we could have expected after a Mw 5.9 event for Italy. As magnitude-intensity regressions are mainly based on historical earthquake data, we handle this issue going back in time and debating the following hypotheses: (a) the 2012 Emilia earthquake sequence shows lower intensity values than expected because the affected urban context is more heterogeneous and much less vulnerable than that in the past; (b) some historical earthquakes, especially those that occurred centuries ago and are provided with little information, could show a tendency to be overestimated in intensity, and consequently in magnitude. In order to give consistency to such hypotheses, we have introduced, as a test, a dual historical reading of the 2012 Emilia earthquake sequence as if it had occurred in the past: the first reading refers to a period prior to the introduction of concrete in buildings assessing the intensity on traditional masonry buildings only. A further historical reading, assessed by using information on monumental buildings only, was performed, and it can be roughly referred to the XVI-XVII centuries. In both cases, intensity values tend to grow significantly. The results could have a relevant impact when considered for seismic hazard assessments if confirmed on a large scale.

Seismic survey probes urban earthquake hazards in Pacific Northwest

USGS Publications Warehouse

Fisher, M.A.; Brocher, T.M.; Hyndman, R.D.; Trehu, A.M.; Weaver, C.S.; Creager, K.C.; Crosson, R.S.; Parsons, T.; Cooper, A. K.; Mosher, D.; Spence, G.; Zelt, B.C.; Hammer, P.T.; Childs, J. R.; Cochrane, G.R.; Chopra, S.; Walia, R.

1999-01-01

A multidisciplinary seismic survey earlier this year in the Pacific Northwest is expected to reveal much new information about the earthquake threat to U.S. and Canadian urban areas there. A disastrous earthquake is a very real possibility in the region. The survey, known as the Seismic Hazards Investigation in Puget Sound (SHIPS), engendered close cooperation among geologists, biologists, environmental groups, and government agencies. It also succeeded in striking a fine balance between the need to prepare for a great earthquake and the requirement to protect a coveted marine environment while operating a large airgun array.

Evidence of the 1762 Arakan and Prior Earthquakes in the Northern Sunda Subduction

NASA Astrophysics Data System (ADS)

Mondal, Dhiman Ranjan

The objective of this dissertation is to understand the seismic hazard associated with Arakan segment of the northern Sunda subduction along SE Bangladesh. In order to do that, it is necessary to document geologic evidence for the 1762 Arakan earthquake and prior events, to help estimate the recurrence interval (repeat time) for that earthquake. Historical records described that the 1762 earthquake caused extensive damage along the Arakan segment of the Sunda subduction system. But the geologic evidence for the earthquake farther north is necessary to better understand its associated seismic hazard to the densely populated nation of Bangladesh. This dissertation presents the results obtained from U/Th dating of the dead and live coral microatolls including their elevations measured by high precision GPS from the Saint Martin's Island, DEM analysis and elevation of terraces from Teknaf coast and fault dislocation modeling based on the data obtained from the Saint Martin's Island and Teknaf. Coral microatolls from Saint Martin's island documents the evidence of the 1762 and prior earthquakes. The U/Th ages documents strong evidence of microatoll die offs related to the 1762 earthquake. The > 2 m elevation difference between the dead microatolls and present-day living corals suggest that the microatolls died due to the coseismic uplift of 1762 Arakan earthquake. This dissertation also provides evidence for two additional earthquakes taking place in 700 and 1140 C.E. which suggests an earthquake recurrence interval of 500 years. Geomorphic studies documented three terraces along the coast of Teknaf. Several marine terraces have been previously documented along the west coast of Myanmar. The youngest of these terraces has been correlated to the coseismic uplift of 1762 Arakan along the Myanmar coast. The terraces along the coast of Teknaf are characterized by flat to semi-flat surfaces followed by sharp topographic rises. DEM (Digital Elevation System) analysis and GPS

Awareness and understanding of earthquake hazards at school

NASA Astrophysics Data System (ADS)

Saraò, Angela; Peruzza, Laura; Barnaba, Carla; Bragato, Pier Luigi

2014-05-01

Schools have a fundamental role in broadening the understanding of natural hazard and risks and in building the awareness in the community. Recent earthquakes in Italy and worldwide, have clearly demonstrated that the poor perception of seismic hazards diminishes the effectiveness of mitigation countermeasures. Since years the Seismology's department of OGS is involved in education projects and public activities to raise awareness about earthquakes. Working together with teachers we aim at developing age-appropriate curricula to improve the student's knowledge about earthquakes, seismic safety, and seismic risk reduction. Some examples of education activities we performed during the last years are here presented. We show our experience with the primary and intermediate schools where, through hands-on activities, we explain the earthquake phenomenon and its effects to kids, but we illustrate also some teaching interventions for high school students. During the past years we lectured classes, we led laboratory and field activities, and we organized summer stages for selected students. In the current year we are leading a project aimed at training high school students on seismic safety through a multidisciplinary approach that involves seismologists, engineers and experts of safety procedures. To combine the objective of dissemination of earthquake culture, also through the knowledge of the past seismicity, with that of a safety culture, we use innovative educational techniques and multimedia resources. Students and teachers, under the guidance of an expert seismologist, organize a combination of hands-on activities for understanding earthquakes in the lab through cheap tools and instrumentations At selected schools we provided the low cost seismometers of the QuakeCatcher network (http://qcn.stanford.edu) for recording earthquakes, and we trained teachers to use such instruments in the lab and to analyze recorded data. Within the same project we are going to train

Earthquake Hazard and Risk in Sub-Saharan Africa: current status of the Global Earthquake model (GEM) initiative in the region

NASA Astrophysics Data System (ADS)

Ayele, Atalay; Midzi, Vunganai; Ateba, Bekoa; Mulabisana, Thifhelimbilu; Marimira, Kwangwari; Hlatywayo, Dumisani J.; Akpan, Ofonime; Amponsah, Paulina; Georges, Tuluka M.; Durrheim, Ray

2013-04-01

Large magnitude earthquakes have been observed in Sub-Saharan Africa in the recent past, such as the Machaze event of 2006 (Mw, 7.0) in Mozambique and the 2009 Karonga earthquake (Mw 6.2) in Malawi. The December 13, 1910 earthquake (Ms = 7.3) in the Rukwa rift (Tanzania) is the largest of all instrumentally recorded events known to have occurred in East Africa. The overall earthquake hazard in the region is on the lower side compared to other earthquake prone areas in the globe. However, the risk level is high enough for it to receive attention of the African governments and the donor community. The latest earthquake hazard map for the sub-Saharan Africa was done in 1999 and updating is long overdue as several development activities in the construction industry is booming allover sub-Saharan Africa. To this effect, regional seismologists are working together under the GEM (Global Earthquake Model) framework to improve incomplete, inhomogeneous and uncertain catalogues. The working group is also contributing to the UNESCO-IGCP (SIDA) 601 project and assessing all possible sources of data for the catalogue as well as for the seismotectonic characteristics that will help to develop a reasonable hazard model in the region. In the current progress, it is noted that the region is more seismically active than we thought. This demands the coordinated effort of the regional experts to systematically compile all available information for a better output so as to mitigate earthquake risk in the sub-Saharan Africa.

Up-to-date Probabilistic Earthquake Hazard Maps for Egypt

NASA Astrophysics Data System (ADS)

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

2018-04-01

An up-to-date earthquake hazard analysis has been performed in Egypt using a probabilistic seismic hazard approach. Through the current study, we use a complete and homogenous earthquake catalog covering the time period between 2200 BC and 2015 AD. Three seismotectonic models representing the seismic activity in and around Egypt are used. A logic-tree framework is applied to allow for the epistemic uncertainty in the declustering parameters, minimum magnitude, seismotectonic setting and ground-motion prediction equations. The hazard analysis is performed for a grid of 0.5° × 0.5° in terms of types of rock site for the peak ground acceleration (PGA) and spectral acceleration at 0.2-, 0.5-, 1.0- and 2.0-s periods. The hazard is estimated for three return periods (72, 475 and 2475 years) corresponding to 50, 10 and 2% probability of exceedance in 50 years. The uniform hazard spectra for the cities of Cairo, Alexandria, Aswan and Nuwbia are constructed. The hazard maps show that the highest ground acceleration values are expected in the northeastern part of Egypt around the Gulf of Aqaba (PGA up to 0.4 g for return period 475 years) and in south Egypt around the city of Aswan (PGA up to 0.2 g for return period 475 years). The Western Desert of Egypt is characterized by the lowest level of hazard (PGA lower than 0.1 g for return period 475 years).

Tectonic styles of future earthquakes in Italy as input data for seismic hazard

NASA Astrophysics Data System (ADS)

Pondrelli, S.; Meletti, C.; Rovida, A.; Visini, F.; D'Amico, V.; Pace, B.

2017-12-01

In a recent elaboration of a new seismogenic zonation and hazard model for Italy, we tried to understand how many indications we have on the tectonic style of future earthquake/rupture. Using all available or recomputed seismic moment tensors for relevant seismic events (Mw starting from 4.5) of the last 100 yrs, first arrival focal mechanisms for less recent earthquakes and also geological data on past activated faults, we collected a database gathering a thousands of data all over the Italian peninsula and regions around it. After several summations of seismic moment tensors, over regular grids of different dimensions and different thicknesses of the seismogenic layer, we applied the same procedure to each of the 50 area sources that were designed in the seismogenic zonation. The results for several seismic zones are very stable, e.g. along the southern Apennines we expect future earthquakes to be mostly extensional, although in the outer part of the chain strike-slip events are possible. In the Northern part of the Apennines we also expect different, opposite tectonic styles for different hypocentral depths. In several zones, characterized by a low seismic moment release, defined for the study region using 1000 yrs of catalog, the next possible tectonic style of future earthquakes is less clear. It is worth to note that for some zones the possible greatest earthquake could be not represented in the available observations. We also add to our analysis the computation of the seismic release rate, computed using a distributed completeness, identified for single great events of the historical seismic catalog for Italy. All these information layers, overlapped and compared, may be used to characterize each new seismogenic zone.

Seismic hazard assessment and pattern recognition of earthquake prone areas in the Po Plain (Italy)

NASA Astrophysics Data System (ADS)

Gorshkov, Alexander; Peresan, Antonella; Soloviev, Alexander; Panza, Giuliano F.

2014-05-01

A systematic and quantitative assessment, capable of providing first-order consistent information about the sites where large earthquakes may occur, is crucial for the knowledgeable seismic hazard evaluation. The methodology for the pattern recognition of areas prone to large earthquakes is based on the morphostructural zoning method (MSZ), which employs topographic data and present-day tectonic structures for the mapping of earthquake-controlling structures (i.e. the nodes formed around lineaments intersections) and does not require the knowledge about past seismicity. The nodes are assumed to be characterized by a uniform set of topographic, geologic, and geophysical parameters; on the basis of such parameters the pattern recognition algorithm defines a classification rule to discriminate seismogenic and non-seismogenic nodes. This methodology has been successfully applied since the early 1970s in a number of regions worldwide, including California, where it permitted the identification of areas that have been subsequently struck by strong events and that previously were not considered prone to strong earthquakes. Recent studies on the Iberian Peninsula and the Rhone Valley, have demonstrated the applicability of MSZ to flat basins, with a relatively flat topography. In this study, the analysis is applied to the Po Plain (Northern Italy), an area characterized by a flat topography, to allow for the systematic identification of the nodes prone to earthquakes with magnitude larger or equal to M=5.0. The MSZ method differs from the standard morphostructural analysis where the term "lineament" is used to define the complex of alignments detectable on topographic maps or on satellite images. According to that definition the lineament is locally defined and the existence of the lineament does not depend on the surrounding areas. In MSZ, the primary element is the block - a relatively homogeneous area - while the lineament is a secondary element of the morphostructure

Earthquake Hazard Assessment: an Independent Review

NASA Astrophysics Data System (ADS)

Kossobokov, Vladimir

2016-04-01

Seismic hazard assessment (SHA), from term-less (probabilistic PSHA or deterministic DSHA) to time-dependent (t-DASH) including short-term earthquake forecast/prediction (StEF), is not an easy task that implies a delicate application of statistics to data of limited size and different accuracy. Regretfully, in many cases of SHA, t-DASH, and StEF, the claims of a high potential and efficiency of the methodology are based on a flawed application of statistics and hardly suitable for communication to decision makers. The necessity and possibility of applying the modified tools of Earthquake Prediction Strategies, in particular, the Error Diagram, introduced by G.M. Molchan in early 1990ies for evaluation of SHA, and the Seismic Roulette null-hypothesis as a measure of the alerted space, is evident, and such a testing must be done in advance claiming hazardous areas and/or times. The set of errors, i.e. the rates of failure and of the alerted space-time volume, compared to those obtained in the same number of random guess trials permits evaluating the SHA method effectiveness and determining the optimal choice of the parameters in regard to specified cost-benefit functions. These and other information obtained in such a testing may supply us with a realistic estimate of confidence in SHA results and related recommendations on the level of risks for decision making in regard to engineering design, insurance, and emergency management. These basics of SHA evaluation are exemplified with a few cases of misleading "seismic hazard maps", "precursors", and "forecast/prediction methods".

Seismic hazard in Hawaii: High rate of large earthquakes and probabilistics ground-motion maps

USGS Publications Warehouse

Klein, F.W.; Frankel, A.D.; Mueller, C.S.; Wesson, R.L.; Okubo, P.G.

2001-01-01

The seismic hazard and earthquake occurrence rates in Hawaii are locally as high as that near the most hazardous faults elsewhere in the United States. We have generated maps of peak ground acceleration (PGA) and spectral acceleration (SA) (at 0.2, 0.3 and 1.0 sec, 5% critical damping) at 2% and 10% exceedance probabilities in 50 years. The highest hazard is on the south side of Hawaii Island, as indicated by the MI 7.0, MS 7.2, and MI 7.9 earthquakes, which occurred there since 1868. Probabilistic values of horizontal PGA (2% in 50 years) on Hawaii's south coast exceed 1.75g. Because some large earthquake aftershock zones and the geometry of flank blocks slipping on subhorizontal decollement faults are known, we use a combination of spatially uniform sources in active flank blocks and smoothed seismicity in other areas to model seismicity. Rates of earthquakes are derived from magnitude distributions of the modem (1959-1997) catalog of the Hawaiian Volcano Observatory's seismic network supplemented by the historic (1868-1959) catalog. Modern magnitudes are ML measured on a Wood-Anderson seismograph or MS. Historic magnitudes may add ML measured on a Milne-Shaw or Bosch-Omori seismograph or MI derived from calibrated areas of MM intensities. Active flank areas, which by far account for the highest hazard, are characterized by distributions with b slopes of about 1.0 below M 5.0 and about 0.6 above M 5.0. The kinked distribution means that large earthquake rates would be grossly under-estimated by extrapolating small earthquake rates, and that longer catalogs are essential for estimating or verifying the rates of large earthquakes. Flank earthquakes thus follow a semicharacteristic model, which is a combination of background seismicity and an excess number of large earthquakes. Flank earthquakes are geometrically confined to rupture zones on the volcano flanks by barriers such as rift zones and the seaward edge of the volcano, which may be expressed by a magnitude

USGS Earthquake Program GPS Use Case : Earthquake Early Warning

DOT National Transportation Integrated Search

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...

Stress Interactions Between the 1976 Magnitude 7.8 Tangshan Earthquake and Adjacent Fault Systems in Northern China

NASA Astrophysics Data System (ADS)

Zhang, Z.; Lin, J.; Chen, Y. J.

2004-12-01

The 28 July 1976 ML = 7.8 Tangshan earthquake struck a highly populated metropolitan center in northern China and was one of the most devastating earthquakes in modern history. Its occurrence has significantly changed the Coulomb stresses on a complex network of strike-slip, normal, and thrust faults in the region, potentially heightened the odds of future earthquakes on some of these fault segments. We have conducted a detailed analysis of the 3D stress effects of the Tangshan earthquake on its neighboring faults, the relationship between stress transfer and aftershock locations, and the implications for future seismic hazard in the region. Available seismic and geodetic data, although limited, indicate that the Tangshan main shock sequence is composed of complex rupture on 2-3 fault segments. The dominant rupture mode is right-lateral strike-slip on two adjoining sub-segments that strike N5¡aE and N35¡aE, respectively. We calculated that the Tangshan main shock sequence has increased the Coulomb failure stress by more than 1 bar in the vicinity of the Lunanxian district to the east, where the largest aftershock (ML = 7.1) occurred 15 hours after the Tangshan main event. The second largest aftershock (ML = 6.8) occurred on the Ninghe fault to the southwest of the main rupture, in a transitional region between the calculated Coulomb stress increase and decrease. The majority of the ML > 5.0 aftershocks also occurred in areas of calculated Coulomb stress increase. Our analyses further indicate that the Coulomb stress on portions of other fault segments, including the Leting and Lulong fault to the east and Yejito fault to the north, may also have been increased. Thus it is critical to obtain estimates of earthquake repeat times on these and other tectonic faults and to acquire continuous GPS and space geodetic measurements. Investigation of stress interaction and earthquake triggering in northern China is not only highly societal relevant but also important for

Comparing the Performance of Japan's Earthquake Hazard Maps to Uniform and Randomized Maps

NASA Astrophysics Data System (ADS)

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

2015-12-01

The devastating 2011 magnitude 9.1 Tohoku earthquake and the resulting shaking and tsunami were much larger than anticipated in earthquake hazard maps. Because this and all other earthquakes that caused ten or more fatalities in Japan since 1979 occurred in places assigned a relatively low hazard, Geller (2011) argued that "all of Japan is at risk from earthquakes, and the present state of seismological science does not allow us to reliably differentiate the risk level in particular geographic areas," so a map showing uniform hazard would be preferable to the existing map. Defenders of the maps countered by arguing that these earthquakes are low-probability events allowed by the maps, which predict the levels of shaking that should expected with a certain probability over a given time. Although such maps are used worldwide in making costly policy decisions for earthquake-resistant construction, how well these maps actually perform is unknown. We explore this hotly-contested issue by comparing how well a 510-year-long record of earthquake shaking in Japan is described by the Japanese national hazard (JNH) maps, uniform maps, and randomized maps. Surprisingly, as measured by the metric implicit in the JNH maps, i.e. that during the chosen time interval the predicted ground motion should be exceeded only at a specific fraction of the sites, both uniform and randomized maps do better than the actual maps. However, using as a metric the squared misfit between maximum observed shaking and that predicted, the JNH maps do better than uniform or randomized maps. These results indicate that the JNH maps are not performing as well as expected, that what factors control map performance is complicated, and that learning more about how maps perform and why would be valuable in making more effective policy.

Earthquake Hazard in the New Madrid Seismic Zone Remains a Concern

USGS Publications Warehouse

Frankel, A.D.; Applegate, D.; Tuttle, M.P.; Williams, R.A.

2009-01-01

There is broad agreement in the scientific community that a continuing concern exists for a major destructive earthquake in the New Madrid seismic zone. Many structures in Memphis, Tenn., St. Louis, Mo., and other communities in the central Mississippi River Valley region are vulnerable and at risk from severe ground shaking. This assessment is based on decades of research on New Madrid earthquakes and related phenomena by dozens of Federal, university, State, and consulting earth scientists. Considerable interest has developed recently from media reports that the New Madrid seismic zone may be shutting down. These reports stem from published research using global positioning system (GPS) instruments with results of geodetic measurements of strain in the Earth's crust. Because of a lack of measurable strain at the surface in some areas of the seismic zone over the past 14 years, arguments have been advanced that there is no buildup of stress at depth within the New Madrid seismic zone and that the zone may no longer pose a significant hazard. As part of the consensus-building process used to develop the national seismic hazard maps, the U.S. Geological Survey (USGS) convened a workshop of experts in 2006 to evaluate the latest findings in earthquake hazards in the Eastern United States. These experts considered the GPS data from New Madrid available at that time that also showed little to no ground movement at the surface. The experts did not find the GPS data to be a convincing reason to lower the assessment of earthquake hazard in the New Madrid region, especially in light of the many other types of data that are used to construct the hazard assessment, several of which are described here.

The Wenchuan, China M8.0 Earthquake: A Lesson and Implication for Seismic Hazard Mitigation

NASA Astrophysics Data System (ADS)

Wang, Z.

2008-12-01

The Wenchuan, China M8.0 earthquake caused great damage and huge casualty. 69,197 people were killed, 374,176 people were injured, and 18,341 people are still missing. The estimated direct economic loss is about 126 billion U.S. dollar. The Wenchuan earthquake again demonstrated that earthquake does not kill people, but the built environments and induced hazards, landslides in particular, do. Therefore, it is critical to strengthen the built environments, such buildings and bridges, and to mitigate the induced hazards in order to avoid such disaster. As a part of the so-called North-South Seismic Zone in China, the Wenchuan earthquake occurred along the Longmen Shan thrust belt which forms a boundary between the Qinghai-Tibet Plateau and the Sichuan basin, and there is a long history (~4,000 years) of seismicity in the area. The historical records show that the area experienced high intensity (i.e., greater than IX) in the past several thousand years. In other words, the area is well-known to have high seismic hazard because of its tectonic setting and seismicity. However, only intensity VII (0.1 to 0.15g PGA) has been considered for seismic design for the built environments in the area. This was one of the main reasons that so many building collapses, particularly the school buildings, during the Wenchuan earthquake. It is clear that the seismic design (i.e., the design ground motion or intensity) is not adequate in the Wenchuan earthquake stricken area. A lesson can be learned from the Wenchuan earthquake on the seismic hazard and risk assessment. A lesson can also be learned from this earthquake on seismic hazard mitigation and/or seismic risk reduction.

Academia Sinica, TW E-science to Assistant Seismic Observations for Earthquake Research, Monitor and Hazard Reduction Surrounding the South China Sea

NASA Astrophysics Data System (ADS)

Huang, Bor-Shouh; Liu, Chun-Chi; Yen, Eric; Liang, Wen-Tzong; Lin, Simon C.; Huang, Win-Gee; Lee, Shiann-Jong; Chen, Hsin-Yen

Experience from the 1994 giant Sumatra earthquake, seismic and tsunami hazard have been considered as important issues in the South China Sea and its surrounding region, and attracted many seismologist's interesting. Currently, more than 25 broadband seismic instruments are currently operated by Institute of Earth Sciences, Academia Sinica in northern Vietnam to study the geodynamic evolution of the Red river fracture zone and rearranged to distribute to southern Vietnam recently to study the geodynamic evolution and its deep structures of the South China Sea. Similar stations are planned to deploy in Philippines in near future. In planning, some high quality stations may be as permanent stations and added continuous GPS observations, and instruments to be maintained and operated by several cooperation institutes, for instance, Institute of Geophysics, Vietnamese Acadamy of Sciences and Technology in Vietnam and Philippine Institute of Volcanology and Seismology in Philippines. Finally, those stations will be planed to upgrade as real time transmission stations for earthquake monitoring and tsunami warning. However, high speed data transfer within different agencies is always a critical issue for successful network operation. By taking advantage of both EGEE and EUAsiaGrid e-Infrastructure, Academia Sinica Grid Computing Centre coordinates researchers from various Asian countries to construct a platform to high performance data transfer for huge parallel computation. Efforts from this data service and a newly build earthquake data centre for data management may greatly improve seismic network performance. Implementation of Grid infrastructure and e-science issues in this region may assistant development of earthquake research, monitor and natural hazard reduction. In the near future, we will search for new cooperation continually from the surrounding countries of the South China Sea to install new seismic stations to construct a complete seismic network of the

Web Services and Other Enhancements at the Northern California Earthquake Data Center

NASA Astrophysics Data System (ADS)

Neuhauser, D. S.; Zuzlewski, S.; Allen, R. M.

2012-12-01

The Northern California Earthquake Data Center (NCEDC) provides data archive and distribution services for seismological and geophysical data sets that encompass northern California. The NCEDC is enhancing its ability to deliver rapid information through Web Services. NCEDC Web Services use well-established web server and client protocols and REST software architecture to allow users to easily make queries using web browsers or simple program interfaces and to receive the requested data in real-time rather than through batch or email-based requests. Data are returned to the user in the appropriate format such as XML, RESP, or MiniSEED depending on the service, and are compatible with the equivalent IRIS DMC web services. The NCEDC is currently providing the following Web Services: (1) Station inventory and channel response information delivered in StationXML format, (2) Channel response information delivered in RESP format, (3) Time series availability delivered in text and XML formats, (4) Single channel and bulk data request delivered in MiniSEED format. The NCEDC is also developing a rich Earthquake Catalog Web Service to allow users to query earthquake catalogs based on selection parameters such as time, location or geographic region, magnitude, depth, azimuthal gap, and rms. It will return (in QuakeML format) user-specified results that can include simple earthquake parameters, as well as observations such as phase arrivals, codas, amplitudes, and computed parameters such as first motion mechanisms, moment tensors, and rupture length. The NCEDC will work with both IRIS and the International Federation of Digital Seismograph Networks (FDSN) to define a uniform set of web service specifications that can be implemented by multiple data centers to provide users with a common data interface across data centers. The NCEDC now hosts earthquake catalogs and waveforms from the US Department of Energy (DOE) Enhanced Geothermal Systems (EGS) monitoring networks. These

Earthquake and tsunami hazard in West Sumatra: integrating science, outreach, and local stakeholder needs

NASA Astrophysics Data System (ADS)

McCaughey, J.; Lubis, A. M.; Huang, Z.; Yao, Y.; Hill, E. M.; Eriksson, S.; Sieh, K.

2012-04-01

The Earth Observatory of Singapore (EOS) is building partnerships with local to provincial government agencies, NGOs, and educators in West Sumatra to inform their policymaking, disaster-risk-reduction, and education efforts. Geodetic and paleoseismic studies show that an earthquake as large as M 8.8 is likely sometime in the coming decades on the Mentawai patch of the Sunda megathrust. This earthquake and its tsunami would be devastating for the Mentawai Islands and neighboring areas of the western Sumatra coast. The low-lying coastal Sumatran city of Padang (pop. ~800,000) has been the object of many research and outreach efforts, especially since 2004. Padang experienced deadly earthquakes in 2007 and 2009 that, though tragedies in their own right, served also as wake-up calls for a larger earthquake to come. However, there remain significant barriers to linking science to policy: extant hazard information is sometimes contradictory or confusing for non-scientists, while turnover of agency leadership and staff means that, in the words of one local advocate, "we keep having to start from zero." Both better hazard knowledge and major infrastructure changes are necessary for risk reduction in Padang. In contrast, the small, isolated villages on the outlying Mentawai Islands have received relatively fewer outreach efforts, yet many villages have the potential for timely evacuation with existing infrastructure. Therefore, knowledge alone can go far toward risk reduction. The tragic October 2010 Mentawai tsunami has inspired further disaster-risk reduction work by local stakeholders. In both locations, we are engaging policymakers and local NGOs, providing science to help inform their work. Through outreach contacts, the Mentawai government requested that we produce the first-ever tsunami hazard map for their islands; this aligns well with scientific interests at EOS. We will work with the Mentawai government on the presentation and explanation of the hazard map, as

Department of Energy Natural Phenomena Hazards Mitigation Program

DOE Office of Scientific and Technical Information (OSTI.GOV)

Murray, R.C.

1993-09-01

This paper will present a summary of past and present accomplishments of the Natural Phenomena Hazards Program that has been ongoing at Lawrence Livermore National Laboratory since 1975. The Natural Phenomena covered includes earthquake; winds, hurricanes, and tornadoes; flooding and precipitation; lightning; and volcanic events. The work is organized into four major areas (1) Policy, requirements, standards, and guidance (2) Technical support, research development, (3) Technology transfer, and (4) Oversight.

Prototype operational earthquake prediction system

USGS Publications Warehouse

Spall, Henry

1986-01-01

An objective if the U.S. Earthquake Hazards Reduction Act of 1977 is to introduce into all regions of the country that are subject to large and moderate earthquakes, systems for predicting earthquakes and assessing earthquake risk. In 1985, the USGS developed for the Secretary of the Interior a program for implementation of a prototype operational earthquake prediction system in southern California.

Assessing Lay Understanding of Common Presentations of Earthquake Hazard Information

NASA Astrophysics Data System (ADS)

Thompson, K. J.; Krantz, D. H.

2010-12-01

The Working Group on California Earthquake Probabilities (WGCEP) includes, in its introduction to earthquake rupture forecast maps, the assertion that "In daily living, people are used to making decisions based on probabilities -- from the flip of a coin (50% probability of heads) to weather forecasts (such as a 30% chance of rain) to the annual chance of being killed by lightning (about 0.0003%)." [3] However, psychology research identifies a large gap between lay and expert perception of risk for various hazards [2], and cognitive psychologists have shown in numerous studies [1,4-6] that people neglect, distort, misjudge, or misuse probabilities, even when given strong guidelines about the meaning of numerical or verbally stated probabilities [7]. The gap between lay and expert use of probability needs to be recognized more clearly by scientific organizations such as WGCEP. This study undertakes to determine how the lay public interprets earthquake hazard information, as presented in graphical map form by the Uniform California Earthquake Rupture Forecast (UCERF), compiled by the WGCEP and other bodies including the USGS and CGS. It also explores alternate ways of presenting hazard data, to determine which presentation format most effectively translates information from scientists to public. Participants both from California and from elsewhere in the United States are included, to determine whether familiarity -- either with the experience of an earthquake, or with the geography of the forecast area -- affects people's ability to interpret an earthquake hazards map. We hope that the comparisons between the interpretations by scientific experts and by different groups of laypeople will both enhance theoretical understanding of factors that affect information transmission and assist bodies such as the WGCEP in their laudable attempts to help people prepare themselves and their communities for possible natural hazards. [1] Kahneman, D & Tversky, A (1979). Prospect

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

USGS Publications Warehouse

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.

Earthquake Hazard Analysis Use Vs30 Data In Palu

NASA Astrophysics Data System (ADS)

Rusydi, Muhammad; Efendi, Rustan; Sandra; Rahmawati

2018-03-01

Palu City is an area passed by Palu-Koro fault and some small faults around it, causing the Palu of city often hit by earthquake. Therefore, this study is intended to mapped the earthquake hazard zones. Determination of this zone is one of aspect that can be used to reducing risk of earthquake disaster. This research was conducted by integrating Vs30 data from USGS with Vs30 from mikrotremor data. Vs30 data from microtremor used to correction Vs30 from USGS. This Results are then used to determine PeakGround Acceleration (PGA) can be used to calculate the impact of earthquake disaster. Results of the study shows that Palu City is in high danger class. Eight sub-districts in Palu City, there are 7 sub-districts that have high danger level, namely Palu Barat, PaluTimur, Palu Selatan, Palu Utara, Tatanga, Mantikulore and Tawaeli.

Rapid field-based landslide hazard assessment in response to post-earthquake emergency

NASA Astrophysics Data System (ADS)

Frattini, Paolo; Gambini, Stefano; Cancelliere, Giorgio

2016-04-01

On April 25, 2015 a Mw 7.8 earthquake occurred 80 km to the northwest of Kathmandu (Nepal). The largest aftershock, occurred on May 12, 2015, was the Mw 7.3 Nepal earthquake (SE of Zham, China), 80 km to the east of Kathmandu. . The earthquakes killed ~9000 people and severely damaged a 10,000 sqkm region in Nepal and neighboring countries. Several thousands of landslides have been triggered during the event, causing widespread damages to mountain villages and the evacuation of thousands of people. Rasuwa was one of the most damaged districts. This contribution describes landslide hazard analysis of the Saramthali, Yarsa and Bhorle VDCs (122 km2, Rasuwa district). Hazard is expressed in terms of qualitative classes (low, medium, high), through a simple matrix approach that combines frequency classes and magnitude classes. The hazard analysis is based primarily on the experience gained during a field survey conducted in September 2014. During the survey, local knowledge has been systematically exploited through interviews with local people that have experienced the earthquake and the coseismic landslides. People helped us to recognize fractures and active deformations, and allowed to reconstruct a correct chronicle of landslide events, in order to assign the landslide events to the first shock, the second shock, or the post-earthquake 2015 monsoon. The field experience was complemented with a standard analysis of the relationship between potential controlling factors and the distribution of landslides reported in Kargel et al (2016). This analysis allowed recognizing the most important controlling factor. This information was integrated with the field observations to verify the mapped units and to complete the mapping in area not accessible for field activity. Finally, the work was completed with the analysis and the use of a detailed landslide inventory produced by the University of Milano Bicocca that covers most of the area affected by coseismic landslides in

The 1909 Taipei earthquake: implication for seismic hazard in Taipei

USGS Publications Warehouse

Kanamori, Hiroo; Lee, William H.K.; Ma, Kuo-Fong

2012-01-01

The 1909 April 14 Taiwan earthquake caused significant damage in Taipei. Most of the information on this earthquake available until now is from the written reports on its macro-seismic effects and from seismic station bulletins. In view of the importance of this event for assessing the shaking hazard in the present-day Taipei, we collected historical seismograms and station bulletins of this event and investigated them in conjunction with other seismological data. We compared the observed seismograms with those from recent earthquakes in similar tectonic environments to characterize the 1909 earthquake. Despite the inevitably large uncertainties associated with old data, we conclude that the 1909 Taipei earthquake is a relatively deep (50–100 km) intraplate earthquake that occurred within the subducting Philippine Sea Plate beneath Taipei with an estimated M_W of 7 ± 0.3. Some intraplate events elsewhere in the world are enriched in high-frequency energy and the resulting ground motions can be very strong. Thus, despite its relatively large depth and a moderately large magnitude, it would be prudent to review the safety of the existing structures in Taipei against large intraplate earthquakes like the 1909 Taipei earthquake.

Vulnerability of port and harbor communities to earthquake and tsunami hazards: The use of GIS in community hazard planning

USGS Publications Warehouse

Wood, Nathan J.; Good, James W.

2004-01-01

AbstractEarthquakes and tsunamis pose significant threats to Pacific Northwest coastal port and harbor communities. Developing holistic mitigation and preparedness strategies to reduce the potential for loss of life and property damage requires community-wide vulnerability assessments that transcend traditional site-specific analyses. The ability of a geographic information system (GIS) to integrate natural, socioeconomic, and hazards information makes it an ideal assessment tool to support community hazard planning efforts. This article summarizes how GIS was used to assess the vulnerability of an Oregon port and harbor community to earthquake and tsunami hazards, as part of a larger risk-reduction planning initiative. The primary purposes of the GIS were to highlight community vulnerability issues and to identify areas that both are susceptible to hazards and contain valued port and harbor community resources. Results of the GIS analyses can help decision makers with limited mitigation resources set priorities for increasing community resiliency to natural hazards.

A global probabilistic tsunami hazard assessment from earthquake sources

USGS Publications Warehouse

Davies, Gareth; Griffin, Jonathan; Lovholt, Finn; Glimsdal, Sylfest; Harbitz, Carl; Thio, Hong Kie; Lorito, Stefano; Basili, Roberto; Selva, Jacopo; Geist, Eric L.; Baptista, Maria Ana

2017-01-01

Large tsunamis occur infrequently but have the capacity to cause enormous numbers of casualties, damage to the built environment and critical infrastructure, and economic losses. A sound understanding of tsunami hazard is required to underpin management of these risks, and while tsunami hazard assessments are typically conducted at regional or local scales, globally consistent assessments are required to support international disaster risk reduction efforts, and can serve as a reference for local and regional studies. This study presents a global-scale probabilistic tsunami hazard assessment (PTHA), extending previous global-scale assessments based largely on scenario analysis. Only earthquake sources are considered, as they represent about 80% of the recorded damaging tsunami events. Globally extensive estimates of tsunami run-up height are derived at various exceedance rates, and the associated uncertainties are quantified. Epistemic uncertainties in the exceedance rates of large earthquakes often lead to large uncertainties in tsunami run-up. Deviations between modelled tsunami run-up and event observations are quantified, and found to be larger than suggested in previous studies. Accounting for these deviations in PTHA is important, as it leads to a pronounced increase in predicted tsunami run-up for a given exceedance rate.

2017 One‐year seismic‐hazard forecast for the central and eastern United States from induced and natural earthquakes

USGS Publications Warehouse

Petersen, Mark D.; Mueller, Charles; Moschetti, Morgan P.; Hoover, Susan M.; Shumway, Allison; McNamara, Daniel E.; Williams, Robert; Llenos, Andrea L.; Ellsworth, William L.; Rubinstein, Justin L.; McGarr, Arthur F.; Rukstales, Kenneth S.

2017-01-01

We produce a one‐year 2017 seismic‐hazard forecast for the central and eastern United States from induced and natural earthquakes that updates the 2016 one‐year forecast; this map is intended to provide information to the public and to facilitate the development of induced seismicity forecasting models, methods, and data. The 2017 hazard model applies the same methodology and input logic tree as the 2016 forecast, but with an updated earthquake catalog. We also evaluate the 2016 seismic‐hazard forecast to improve future assessments. The 2016 forecast indicated high seismic hazard (greater than 1% probability of potentially damaging ground shaking in one year) in five focus areas: Oklahoma–Kansas, the Raton basin (Colorado/New Mexico border), north Texas, north Arkansas, and the New Madrid Seismic Zone. During 2016, several damaging induced earthquakes occurred in Oklahoma within the highest hazard region of the 2016 forecast; all of the 21 moment magnitude (M) ≥4 and 3 M≥5 earthquakes occurred within the highest hazard area in the 2016 forecast. Outside the Oklahoma–Kansas focus area, two earthquakes with M≥4 occurred near Trinidad, Colorado (in the Raton basin focus area), but no earthquakes with M≥2.7 were observed in the north Texas or north Arkansas focus areas. Several observations of damaging ground‐shaking levels were also recorded in the highest hazard region of Oklahoma. The 2017 forecasted seismic rates are lower in regions of induced activity due to lower rates of earthquakes in 2016 compared with 2015, which may be related to decreased wastewater injection caused by regulatory actions or by a decrease in unconventional oil and gas production. Nevertheless, the 2017 forecasted hazard is still significantly elevated in Oklahoma compared to the hazard calculated from seismicity before 2009.

Documentation for Initial Seismic Hazard Maps for Haiti

USGS Publications Warehouse

Frankel, Arthur; Harmsen, Stephen; Mueller, Charles; Calais, Eric; Haase, Jennifer

2010-01-01

In response to the urgent need for earthquake-hazard information after the tragic disaster caused by the moment magnitude (M) 7.0 January 12, 2010, earthquake, we have constructed initial probabilistic seismic hazard maps for Haiti. These maps are based on the current information we have on fault slip rates and historical and instrumental seismicity. These initial maps will be revised and improved as more data become available. In the short term, more extensive logic trees will be developed to better capture the uncertainty in key parameters. In the longer term, we will incorporate new information on fault parameters and previous large earthquakes obtained from geologic fieldwork. These seismic hazard maps are important for the management of the current crisis and the development of building codes and standards for the rebuilding effort. The boundary between the Caribbean and North American Plates in the Hispaniola region is a complex zone of deformation. The highly oblique ~20 mm/yr convergence between the two plates (DeMets and others, 2000) is partitioned between subduction zones off of the northern and southeastern coasts of Hispaniola and strike-slip faults that transect the northern and southern portions of the island. There are also thrust faults within the island that reflect the compressional component of motion caused by the geometry of the plate boundary. We follow the general methodology developed for the 1996 U.S. national seismic hazard maps and also as implemented in the 2002 and 2008 updates. This procedure consists of adding the seismic hazard calculated from crustal faults, subduction zones, and spatially smoothed seismicity for shallow earthquakes and Wadati-Benioff-zone earthquakes. Each one of these source classes will be described below. The lack of information on faults in Haiti requires many assumptions to be made. These assumptions will need to be revisited and reevaluated as more fieldwork and research are accomplished. We made two sets of

Cruise report for A1-98-SC southern California Earthquake Hazards Project

USGS Publications Warehouse

Normark, William R.; Bohannon, Robert G.; Sliter, Ray; Dunhill, Gita; Scholl, David W.; Laursen, Jane; Reid, Jane A.; Holton, David

1999-01-01

The focus of the Southern California Earthquake Hazards project, within the Western Region Coastal and Marine Geology team (WRCMG), is to identify the landslide and earthquake hazards and related ground-deformation processes that can potentially impact the social and economic well-being of the inhabitants of the Southern California coastal region, the most populated urban corridor along the U.S. Pacific margin. The primary objective is to help mitigate the earthquake hazards for the Southern California region by improving our understanding of how deformation is distributed (spatially and temporally) in the offshore with respect to the onshore region. To meet this overall objective, we are investigating the distribution, character, and relative intensity of active (i.e., primarily Holocene) deformation within the basins and along the shelf adjacent to the most highly populated areas (see Fig. 1). In addition, the project will examine the Pliocene-Pleistocene record of how this deformation has shifted in space and time. The results of this study should improve our knowledge of shifting deformation for both the long-term (105 to several 106 yr) and short-term (<50 ky) time frames and enable us to identify actively deforming structures that may constitute current significant seismic hazards.

Earthquake hazards to domestic water distribution systems in Salt Lake County, Utah

USGS Publications Warehouse

Highland, Lynn M.

1985-01-01

A magnitude-7. 5 earthquake occurring along the central portion of the Wasatch Fault, Utah, may cause significant damage to Salt Lake County's domestic water system. This system is composed of water treatment plants, aqueducts, distribution mains, and other facilities that are vulnerable to ground shaking, liquefaction, fault movement, and slope failures. Recent investigations into surface faulting, landslide potential, and earthquake intensity provide basic data for evaluating the potential earthquake hazards to water-distribution systems in the event of a large earthquake. Water supply system components may be vulnerable to one or more earthquake-related effects, depending on site geology and topography. Case studies of water-system damage by recent large earthquakes in Utah and in other regions of the United States offer valuable insights in evaluating water system vulnerability to earthquakes.

Seismic‐hazard forecast for 2016 including induced and natural earthquakes in the central and eastern United States

USGS Publications Warehouse

Petersen, Mark D.; Mueller, Charles; Moschetti, Morgan P.; Hoover, Susan M.; Llenos, Andrea L.; Ellsworth, William L.; Michael, Andrew J.; Rubinstein, Justin L.; McGarr, Arthur F.; Rukstales, Kenneth S.

2016-01-01

The U.S. Geological Survey (USGS) has produced a one‐year (2016) probabilistic seismic‐hazard assessment for the central and eastern United States (CEUS) that includes contributions from both induced and natural earthquakes that are constructed with probabilistic methods using alternative data and inputs. This hazard assessment builds on our 2016 final model (Petersen et al., 2016) by adding sensitivity studies, illustrating hazard in new ways, incorporating new population data, and discussing potential improvements. The model considers short‐term seismic activity rates (primarily 2014–2015) and assumes that the activity rates will remain stationary over short time intervals. The final model considers different ways of categorizing induced and natural earthquakes by incorporating two equally weighted earthquake rate submodels that are composed of alternative earthquake inputs for catalog duration, smoothing parameters, maximum magnitudes, and ground‐motion models. These alternatives represent uncertainties on how we calculate earthquake occurrence and the diversity of opinion within the science community. In this article, we also test sensitivity to the minimum moment magnitude between M 4 and M 4.7 and the choice of applying a declustered catalog with b=1.0 rather than the full catalog with b=1.3. We incorporate two earthquake rate submodels: in the informed submodel we classify earthquakes as induced or natural, and in the adaptive submodel we do not differentiate. The alternative submodel hazard maps both depict high hazard and these are combined in the final model. Results depict several ground‐shaking measures as well as intensity and include maps showing a high‐hazard level (1% probability of exceedance in 1 year or greater). Ground motions reach 0.6g horizontal peak ground acceleration (PGA) in north‐central Oklahoma and southern Kansas, and about 0.2g PGA in the Raton basin of Colorado and New Mexico, in central Arkansas, and in

Earthquake Hazards.

ERIC Educational Resources Information Center

Donovan, Neville

1979-01-01

Provides a survey and a review of earthquake activity and global tectonics from the advancement of the theory of continental drift to the present. Topics include: an identification of the major seismic regions of the earth, seismic measurement techniques, seismic design criteria for buildings, and the prediction of earthquakes. (BT)

Modified Mercalli Intensity Assignments for the May 16, 1909, Northern Plains Earthquake

USGS Publications Warehouse

Bakun, W.H.; Stickney, M.C.; Rogers, G.

2009-01-01

We combine newspaper accounts and Nuttli's (1976) isoseismal map to assign modified Mercalli intensity (MMI) at 76 towns for the May 16, 1909 Northern Plains earthquake. The earthquake was felt across more than 1,500,000 km2 in the States of Minnesota, Montana, North Dakota, South Dakota, and Wyoming and the Provinces of Alberta, Manitoba, Ontario, and Saskatchewan.

Volcano and earthquake hazards in the Crater Lake region, Oregon

USGS Publications Warehouse

Bacon, Charles R.; Mastin, Larry G.; Scott, Kevin M.; Nathenson, Manuel

1997-01-01

Crater Lake lies in a basin, or caldera, formed by collapse of the Cascade volcano known as Mount Mazama during a violent, climactic eruption about 7,700 years ago. This event dramatically changed the character of the volcano so that many potential types of future events have no precedent there. This potentially active volcanic center is contained within Crater Lake National Park, visited by 500,000 people per year, and is adjacent to the main transportation corridor east of the Cascade Range. Because a lake is now present within the most likely site of future volcanic activity, many of the hazards at Crater Lake are different from those at most other Cascade volcanoes. Also significant are many faults near Crater Lake that clearly have been active in the recent past. These faults, and historic seismicity, indicate that damaging earthquakes can occur there in the future. This report describes the various types of volcano and earthquake hazards in the Crater Lake area, estimates of the likelihood of future events, recommendations for mitigation, and a map of hazard zones. The main conclusions are summarized below.

Sources of Seismic Hazard in British Columbia: What Controls Earthquakes in the Crust?

NASA Astrophysics Data System (ADS)

Balfou, Natalie Joy

This thesis examines processes causing faulting in the North American crust in the northern Cascadia subduction zone. A combination of seismological methods, including source mechanism determination, stress inversion and earthquake relocations are used to determine where earthquakes occur and what forces influence faulting. We also determine if forces that control faulting can be monitored using seismic anisotropy. Investigating the processes that contribute to faulting in the crust is important because these earthquakes pose significant hazard to the large population centres in British Columbia and Washington State. To determine where crustal earthquakes occur we apply double-difference earthquake relocation techniques to events in the Fraser River Valley, British Columbia, and the San Juan Islands, Washington. This technique is used to identify "hidden" active structures using both catalogue and waveform cross-correlation data. Results have significantly reduced uncertainty over routine catalogue locations and show lineations in areas of clustered seismicity. In the Fraser River Valley these lineations or streaks appear to be hidden structures that do not disrupt near-surface sediments; however, in the San Juan Islands the identified lineation can be related to recently mapped surface expressions of faults. To determine forces that influence faulting we investigate the orientation and sources of stress using Bayesian inversion results from focal mechanism data. More than ˜600 focal mechanisms from crustal earthquakes are calculated to identify the dominant style of faulting and inverted to estimate the principal stress orientations and the stress ratio. Results indicate the maximum horizontal compressive stress (SHmax) orientation changes with distance from the subduction interface, from margin-normal along the coast to margin-parallel further inland. We relate the margin-normal stress direction to subduction-related strain rates due to the locked interface

Program and plans of the U.S. Geological Survey for producing information needed in National Seismic hazards and risk assessment, fiscal years 1980-84

USGS Publications Warehouse

Hays, Walter W.

1979-01-01

In accordance with the provisions of the Earthquake Hazards Reduction Act of 1977 (Public Law 95-124), the U.S. Geological Survey has developed comprehensive plans for producing information needed to assess seismic hazards and risk on a national scale in fiscal years 1980-84. These plans are based on a review of the needs of Federal Government agencies, State and local government agencies, engineers and scientists engaged in consulting and research, professional organizations and societies, model code groups, and others. The Earthquake Hazards Reduction Act provided an unprecedented opportunity for participation in a national program by representatives of State and local governments, business and industry, the design professions, and the research community. The USGS and the NSF (National Science Foundation) have major roles in the national program. The ultimate goal of the program is to reduce losses from earthquakes. Implementation of USGS research in the Earthquake Hazards Reduction Program requires the close coordination of responsibility between Federal, State and local governments. The projected research plan in national seismic hazards and risk for fiscal years 1980-84 will be accomplished by USGS and non-USGS scientists and engineers. The latter group will participate through grants and contracts. The research plan calls for (1) national maps based on existing methods, (2) improved definition of earthquake source zones nationwide, (3) development of improved methodology, (4) regional maps based on the improved methodology, and (5) post-earthquake investigations. Maps and reports designed to meet the needs, priorities, concerns, and recommendations of various user groups will be the products of this research and provide the technical basis for improved implementation.

Examples of Communicating Uncertainty Applied to Earthquake Hazard and Risk Products

NASA Astrophysics Data System (ADS)

Wald, D. J.

2013-12-01

When is communicating scientific modeling uncertainty effective? One viewpoint is that the answer depends on whether one is communicating hazard or risk: hazards have quantifiable uncertainties (which, granted, are often ignored), yet risk uncertainties compound uncertainties inherent in the hazard with those of the risk calculations, and are thus often larger. Larger, yet more meaningful: since risk entails societal impact of some form, consumers of such information tend to have a better grasp of the potential uncertainty ranges for loss information than they do for less-tangible hazard values (like magnitude, peak acceleration, or stream flow). I present two examples that compare and contrast communicating uncertainty for earthquake hazard and risk products. The first example is the U.S. Geological Survey's (USGS) ShakeMap system, which portrays the uncertain, best estimate of the distribution and intensity of shaking over the potentially impacted region. The shaking intensity is well constrained at seismograph locations yet is uncertain elsewhere, so shaking uncertainties are quantified and presented spatially. However, with ShakeMap, it seems that users tend to believe what they see is accurate in part because (1) considering the shaking uncertainty complicates the picture, and (2) it would not necessarily alter their decision-making. In contrast, when it comes to making earthquake-response decisions based on uncertain loss estimates, actions tend to be made only after analysis of the confidence in (or source of) such estimates. Uncertain ranges of loss estimates instill tangible images for users, and when such uncertainties become large, intuitive reality-check alarms go off, for example, when the range of losses presented become too wide to be useful. The USGS Prompt Assessment of Global Earthquakes for Response (PAGER) system, which in near-real time alerts users to the likelihood of ranges of potential fatalities and economic impact, is aimed at

History of Modern Earthquake Hazard Mapping and Assessment in California Using a Deterministic or Scenario Approach

NASA Astrophysics Data System (ADS)

Mualchin, Lalliana

2011-03-01

Modern earthquake ground motion hazard mapping in California began following the 1971 San Fernando earthquake in the Los Angeles metropolitan area of southern California. Earthquake hazard assessment followed a traditional approach, later called Deterministic Seismic Hazard Analysis (DSHA) in order to distinguish it from the newer Probabilistic Seismic Hazard Analysis (PSHA). In DSHA, seismic hazard in the event of the Maximum Credible Earthquake (MCE) magnitude from each of the known seismogenic faults within and near the state are assessed. The likely occurrence of the MCE has been assumed qualitatively by using late Quaternary and younger faults that are presumed to be seismogenic, but not when or within what time intervals MCE may occur. MCE is the largest or upper-bound potential earthquake in moment magnitude, and it supersedes and automatically considers all other possible earthquakes on that fault. That moment magnitude is used for estimating ground motions by applying it to empirical attenuation relationships, and for calculating ground motions as in neo-DSHA (Z uccolo et al., 2008). The first deterministic California earthquake hazard map was published in 1974 by the California Division of Mines and Geology (CDMG) which has been called the California Geological Survey (CGS) since 2002, using the best available fault information and ground motion attenuation relationships at that time. The California Department of Transportation (Caltrans) later assumed responsibility for printing the refined and updated peak acceleration contour maps which were heavily utilized by geologists, seismologists, and engineers for many years. Some engineers involved in the siting process of large important projects, for example, dams and nuclear power plants, continued to challenge the map(s). The second edition map was completed in 1985 incorporating more faults, improving MCE's estimation method, and using new ground motion attenuation relationships from the latest published

Physics-Based Hazard Assessment for Critical Structures Near Large Earthquake Sources

NASA Astrophysics Data System (ADS)

Hutchings, L.; Mert, A.; Fahjan, Y.; Novikova, T.; Golara, A.; Miah, M.; Fergany, E.; Foxall, W.

2017-09-01

We argue that for critical structures near large earthquake sources: (1) the ergodic assumption, recent history, and simplified descriptions of the hazard are not appropriate to rely on for earthquake ground motion prediction and can lead to a mis-estimation of the hazard and risk to structures; (2) a physics-based approach can address these issues; (3) a physics-based source model must be provided to generate realistic phasing effects from finite rupture and model near-source ground motion correctly; (4) wave propagations and site response should be site specific; (5) a much wider search of possible sources of ground motion can be achieved computationally with a physics-based approach; (6) unless one utilizes a physics-based approach, the hazard and risk to structures has unknown uncertainties; (7) uncertainties can be reduced with a physics-based approach, but not with an ergodic approach; (8) computational power and computer codes have advanced to the point that risk to structures can be calculated directly from source and site-specific ground motions. Spanning the variability of potential ground motion in a predictive situation is especially difficult for near-source areas, but that is the distance at which the hazard is the greatest. The basis of a "physical-based" approach is ground-motion syntheses derived from physics and an understanding of the earthquake process. This is an overview paper and results from previous studies are used to make the case for these conclusions. Our premise is that 50 years of strong motion records is insufficient to capture all possible ranges of site and propagation path conditions, rupture processes, and spatial geometric relationships between source and site. Predicting future earthquake scenarios is necessary; models that have little or no physical basis but have been tested and adjusted to fit available observations can only "predict" what happened in the past, which should be considered description as opposed to prediction

The January 2014 Northern Cuba Earthquake Sequence - Unusual Location and Unexpected Source Mechanism Variability

NASA Astrophysics Data System (ADS)

Braunmiller, J.; Thompson, G.; McNutt, S. R.

2017-12-01

On 9 January 2014, a magnitude Mw=5.1 earthquake occurred along the Bahamas-Cuba suture at the northern coast of Cuba revealing a surprising seismic hazard source for both Cuba and southern Florida where it was widely felt. Due to its location, the event and its aftershocks (M>3.5) were recorded only at far distances (300+ km) resulting in high-detection thresholds, low location accuracy, and limited source parameter resolution. We use three-component regional seismic data to study the sequence. High-pass filtered seismograms at the closest site in southern Florida are similar in character suggesting a relatively tight event cluster and revealing additional, smaller aftershocks not included in the ANSS or ISC catalogs. Aligning on the P arrival and low-pass filtering (T>10 s) uncovers a surprise polarity flip of the large amplitude surface waves on vertical seismograms for some aftershocks relative to the main shock. We performed regional moment tensor inversions of the main shock and its largest aftershocks using complete three-component seismograms from stations distributed throughout the region to confirm the mechanism changes. Consistent with the GCMT solution, we find an E-W trending normal faulting mechanism for the main event and for one immediate aftershock. Two aftershocks indicate E-W trending reverse faulting with essentially flipped P- and T-axes relative to the normal faulting events (and the same B-axes). Within uncertainties, depths of the two event families are indistinguishable and indicate shallow faulting (<10 km). One intriguing possible interpretation is that both families ruptured the same fault with reverse mechanisms compensating for overshooting. However, activity could also be spatially separated either vertically (with reverse mechanisms possibly below extension) or laterally. The shallow source depth and the 200-km long uplifted chain of islands indicate that larger, shallow and thus potentially tsunamigenic earthquakes could occur just

Deterministic seismogenic scenarios based on asperities spatial distribution to assess tsunami hazard on northern Chile (18°S to 24°S)

NASA Astrophysics Data System (ADS)

González-Carrasco, J. F.

2016-12-01

Southern Peru and northern Chile coastal areas, extended between 12º to 24ºS, have been recognized as a mature seismic gap with a high seismogenic potential associated to seismic moment deficit accumulated since 1877. An important scientific question is which will be the breaking pattern of a future megathrust earthquake, being relevant from hazard assessment perspective. During the last decade, the occurrence of three major subduction earthquakes has given the possibility to acquire outstanding geophysical and geological information to know the behavior of phenomena. An interesting result is the relationship between the maximum slip areas and the spatial distribution of asperities in subduction zones. In this contribution, we propose a methodology to identify a regional pattern of main asperities to construct reliable seismogenic scenarios in a seismic gap. We follow a deterministic approach to explore the distribution of asperities segmentation using geophysical and geodetic data as trench-parallel gravity anomaly (TPGA), interseismic coupling (ISC), b-value, historical moment release, residual bathymetric and gravity anomalies. The combined information represents physical constraints for short and long term suitable regions for future mega earthquakes. To illuminate the asperities distribution, we construct profiles using fault coordinates, along-strike and down-dip direction, of all proxies to define the boundaries of a major asperities (> 100 km). The geometry of a major asperity is useful to define a finite set of future deterministic seismogenic scenarios to evaluate tsunamigenic hazard in main cities of northern zone of Chile (18°S to 24°S).

Seismic hazard and risks based on the Unified Scaling Law for Earthquakes

NASA Astrophysics Data System (ADS)

Kossobokov, Vladimir; Nekrasova, Anastasia

2014-05-01

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

Proceedings of Conference V: communicating earthquake hazard reduction information: convened under auspices of National Earthquake Hazards Reduction Program 22-24 May, 1978

USGS Publications Warehouse

Hays, Walter W.

1978-01-01

(11) achieving landslide hazard reduction. The objective was to identify the most significant lessons learned during the course of each experience and to develop recommendations for improving communication that might be incorporated in the search program of the USGS.

Earthquake-induced subsidence and burial of late holocene archaeological sites, northern Oregon coast

USGS Publications Warehouse

Minor, R.; Grant, W.C.

1996-01-01

Fire hearths associated with prehistoric Native American occupation lie within the youngest buried lowland soil of the estuaries along the Salmon and Nehalem rivers on the northern Oregon coast. This buried soil is the result of sudden subsidence induced by a great earthquake about 300 years ago along the Cascadia subduction zone, which extends offshore along the North Pacific Coast from Vancouver Island to northern California. The earthquake 300 years ago was the latest in a series of subsidence events along the Cascadia subduction zone over the last several thousand years. Over the long term, subsidence and burial of prehistoric settlements as a result of Cascadia subduction zone earthquakes have almost certainly been an important factor contributing to the limited time depth of the archaeological record along this section of the North Pacific Coast. Copyright ?? by the Society for American Archaeology.

Earthquake hazard assessment in the Zagros Orogenic Belt of Iran using a fuzzy rule-based model

NASA Astrophysics Data System (ADS)

Farahi Ghasre Aboonasr, Sedigheh; Zamani, Ahmad; Razavipour, Fatemeh; Boostani, Reza

2017-08-01

Producing accurate seismic hazard map and predicting hazardous areas is necessary for risk mitigation strategies. In this paper, a fuzzy logic inference system is utilized to estimate the earthquake potential and seismic zoning of Zagros Orogenic Belt. In addition to the interpretability, fuzzy predictors can capture both nonlinearity and chaotic behavior of data, where the number of data is limited. In this paper, earthquake pattern in the Zagros has been assessed for the intervals of 10 and 50 years using fuzzy rule-based model. The Molchan statistical procedure has been used to show that our forecasting model is reliable. The earthquake hazard maps for this area reveal some remarkable features that cannot be observed on the conventional maps. Regarding our achievements, some areas in the southern (Bandar Abbas), southwestern (Bandar Kangan) and western (Kermanshah) parts of Iran display high earthquake severity even though they are geographically far apart.

Data Files for Ground-Motion Simulations of the 1906 San Francisco Earthquake and Scenario Earthquakes on the Northern San Andreas Fault

USGS Publications Warehouse

Aagaard, Brad T.; Barall, Michael; Brocher, Thomas M.; Dolenc, David; Dreger, Douglas; Graves, Robert W.; Harmsen, Stephen; Hartzell, Stephen; Larsen, Shawn; McCandless, Kathleen; Nilsson, Stefan; Petersson, N. Anders; Rodgers, Arthur; Sjogreen, Bjorn; Zoback, Mary Lou

2009-01-01

This data set contains results from ground-motion simulations of the 1906 San Francisco earthquake, seven hypothetical earthquakes on the northern San Andreas Fault, and the 1989 Loma Prieta earthquake. The bulk of the data consists of synthetic velocity time-histories. Peak ground velocity on a 1/60th degree grid and geodetic displacements from the simulations are also included. Details of the ground-motion simulations and analysis of the results are discussed in Aagaard and others (2008a,b).

Rapid earthquake hazard and loss assessment for Euro-Mediterranean region

NASA Astrophysics Data System (ADS)

Erdik, Mustafa; Sesetyan, Karin; Demircioglu, Mine; Hancilar, Ufuk; Zulfikar, Can; Cakti, Eser; Kamer, Yaver; Yenidogan, Cem; Tuzun, Cuneyt; Cagnan, Zehra; Harmandar, Ebru

2010-10-01

The almost-real time estimation of ground shaking and losses after a major earthquake in the Euro-Mediterranean region was performed in the framework of the Joint Research Activity 3 (JRA-3) component of the EU FP6 Project entitled "Network of Research Infra-structures for European Seismology, NERIES". This project consists of finding the most likely location of the earthquake source by estimating the fault rupture parameters on the basis of rapid inversion of data from on-line regional broadband stations. It also includes an estimation of the spatial distribution of selected site-specific ground motion parameters at engineering bedrock through region-specific ground motion prediction equations (GMPEs) or physical simulation of ground motion. By using the Earthquake Loss Estimation Routine (ELER) software, the multi-level methodology developed for real time estimation of losses is capable of incorporating regional variability and sources of uncertainty stemming from GMPEs, fault finiteness, site modifications, inventory of physical and social elements subjected to earthquake hazard and the associated vulnerability relationships.

Effects of Strike-Slip Fault Segmentation on Earthquake Energy and Seismic Hazard

NASA Astrophysics Data System (ADS)

Madden, E. H.; Cooke, M. L.; Savage, H. M.; McBeck, J.

2014-12-01

Many major strike-slip faults are segmented along strike, including those along plate boundaries in California and Turkey. Failure of distinct fault segments at depth may be the source of multiple pulses of seismic radiation observed for single earthquakes. However, how and when segmentation affects fault behavior and energy release is the basis of many outstanding questions related to the physics of faulting and seismic hazard. These include the probability for a single earthquake to rupture multiple fault segments and the effects of segmentation on earthquake magnitude, radiated seismic energy, and ground motions. Using numerical models, we quantify components of the earthquake energy budget, including the tectonic work acting externally on the system, the energy of internal rock strain, the energy required to overcome fault strength and initiate slip, the energy required to overcome frictional resistance during slip, and the radiated seismic energy. We compare the energy budgets of systems of two en echelon fault segments with various spacing that include both releasing and restraining steps. First, we allow the fault segments to fail simultaneously and capture the effects of segmentation geometry on the earthquake energy budget and on the efficiency with which applied displacement is accommodated. Assuming that higher efficiency correlates with higher probability for a single, larger earthquake, this approach has utility for assessing the seismic hazard of segmented faults. Second, we nucleate slip along a weak portion of one fault segment and let the quasi-static rupture propagate across the system. Allowing fractures to form near faults in these models shows that damage develops within releasing steps and promotes slip along the second fault, while damage develops outside of restraining steps and can prohibit slip along the second fault. Work is consumed in both the propagation of and frictional slip along these new fractures, impacting the energy available

Aftereffects of Subduction-Zone Earthquakes: Potential Tsunami Hazards along the Japan Sea Coast.

PubMed

Minoura, Koji; Sugawara, Daisuke; Yamanoi, Tohru; Yamada, Tsutomu

2015-10-01

The 2011 Tohoku-Oki Earthquake is a typical subduction-zone earthquake and is the 4th largest earthquake after the beginning of instrumental observation of earthquakes in the 19th century. In fact, the 2011 Tohoku-Oki Earthquake displaced the northeast Japan island arc horizontally and vertically. The displacement largely changed the tectonic situation of the arc from compressive to tensile. The 9th century in Japan was a period of natural hazards caused by frequent large-scale earthquakes. The aseismic tsunamis that inflicted damage on the Japan Sea coast in the 11th century were related to the occurrence of massive earthquakes that represented the final stage of a period of high seismic activity. Anti-compressive tectonics triggered by the subduction-zone earthquakes induced gravitational instability, which resulted in the generation of tsunamis caused by slope failing at the arc-back-arc boundary. The crustal displacement after the 2011 earthquake infers an increased risk of unexpected local tsunami flooding in the Japan Sea coastal areas.

Hazard assessment of long-period ground motions for the Nankai Trough earthquakes

NASA Astrophysics Data System (ADS)

Maeda, T.; Morikawa, N.; Aoi, S.; Fujiwara, H.

2013-12-01

We evaluate a seismic hazard for long-period ground motions associated with the Nankai Trough earthquakes (M8~9) in southwest Japan. Large interplate earthquakes occurring around the Nankai Trough have caused serious damages due to strong ground motions and tsunami; most recent events were in 1944 and 1946. Such large interplate earthquake potentially causes damages to high-rise and large-scale structures due to long-period ground motions (e.g., 1985 Michoacan earthquake in Mexico, 2003 Tokachi-oki earthquake in Japan). The long-period ground motions are amplified particularly on basins. Because major cities along the Nankai Trough have developed on alluvial plains, it is therefore important to evaluate long-period ground motions as well as strong motions and tsunami for the anticipated Nankai Trough earthquakes. The long-period ground motions are evaluated by the finite difference method (FDM) using 'characterized source models' and the 3-D underground structure model. The 'characterized source model' refers to a source model including the source parameters necessary for reproducing the strong ground motions. The parameters are determined based on a 'recipe' for predicting strong ground motion (Earthquake Research Committee (ERC), 2009). We construct various source models (~100 scenarios) giving the various case of source parameters such as source region, asperity configuration, and hypocenter location. Each source region is determined by 'the long-term evaluation of earthquakes in the Nankai Trough' published by ERC. The asperity configuration and hypocenter location control the rupture directivity effects. These parameters are important because our preliminary simulations are strongly affected by the rupture directivity. We apply the system called GMS (Ground Motion Simulator) for simulating the seismic wave propagation based on 3-D FDM scheme using discontinuous grids (Aoi and Fujiwara, 1999) to our study. The grid spacing for the shallow region is 200 m and

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

NASA Astrophysics Data System (ADS)

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.

Salient beliefs about earthquake hazards and household preparedness.

PubMed

Becker, Julia S; Paton, Douglas; Johnston, David M; Ronan, Kevin R

2013-09-01

Prior research has found little or no direct link between beliefs about earthquake risk and household preparedness. Furthermore, only limited work has been conducted on how people's beliefs influence the nature and number of preparedness measures adopted. To address this gap, 48 qualitative interviews were undertaken with residents in three urban locations in New Zealand subject to seismic risk. The study aimed to identify the diverse hazard and preparedness-related beliefs people hold and to articulate how these are influenced by public education to encourage preparedness. The study also explored how beliefs and competencies at personal, social, and environmental levels interact to influence people's risk management choices. Three main categories of beliefs were found: hazard beliefs; preparedness beliefs; and personal beliefs. Several salient beliefs found previously to influence the preparedness process were confirmed by this study, including beliefs related to earthquakes being an inevitable and imminent threat, self-efficacy, outcome expectancy, personal responsibility, responsibility for others, and beliefs related to denial, fatalism, normalization bias, and optimistic bias. New salient beliefs were also identified (e.g., preparedness being a "way of life"), as well as insight into how some of these beliefs interact within the wider informational and societal context. © 2013 Society for Risk Analysis.

Rupture process of large earthquakes in the northern Mexico subduction zone

NASA Astrophysics Data System (ADS)

Ruff, Larry J.; Miller, Angus D.

1994-03-01

The Cocos plate subducts beneath North America at the Mexico trench. The northernmost segment of this trench, between the Orozco and Rivera fracture zones, has ruptured in a sequence of five large earthquakes from 1973 to 1985; the Jan. 30, 1973 Colima event ( M s 7.5) at the northern end of the segment near Rivera fracture zone; the Mar. 14, 1979 Petatlan event ( M s 7.6) at the southern end of the segment on the Orozco fracture zone; the Oct. 25, 1981 Playa Azul event ( M s 7.3) in the middle of the Michoacan “gap”; the Sept. 19, 1985 Michoacan mainshock ( M s 8.1); and the Sept. 21, 1985 Michoacan aftershock ( M s 7.6) that reruptured part of the Petatlan zone. Body wave inversion for the rupture process of these earthquakes finds the best: earthquake depth; focal mechanism; overall source time function; and seismic moment, for each earthquake. In addition, we have determined spatial concentrations of seismic moment release for the Colima earthquake, and the Michoacan mainshock and aftershock. These spatial concentrations of slip are interpreted as asperities; and the resultant asperity distribution for Mexico is compared to other subduction zones. The body wave inversion technique also determines the Moment Tensor Rate Functions; but there is no evidence for statistically significant changes in the moment tensor during rupture for any of the five earthquakes. An appendix describes the Moment Tensor Rate Functions methodology in detail. The systematic bias between global and regional determinations of epicentral locations in Mexico must be resolved to enable plotting of asperities with aftershocks and geographic features. We have spatially “shifted” all of our results to regional determinations of epicenters. The best point source depths for the five earthquakes are all above 30 km, consistent with the idea that the down-dip edge of the seismogenic plate interface in Mexico is shallow compared to other subduction zones. Consideration of uncertainties in

Web Services and Data Enhancements at the Northern California Earthquake Data Center

NASA Astrophysics Data System (ADS)

Neuhauser, D. S.; Zuzlewski, S.; Lombard, P. N.; Allen, R. M.

2013-12-01

The Northern California Earthquake Data Center (NCEDC) provides data archive and distribution services for seismological and geophysical data sets that encompass northern California. The NCEDC is enhancing its ability to deliver rapid information through Web Services. NCEDC Web Services use well-established web server and client protocols and REST software architecture to allow users to easily make queries using web browsers or simple program interfaces and to receive the requested data in real-time rather than through batch or email-based requests. Data are returned to the user in the appropriate format such as XML, RESP, simple text, or MiniSEED depending on the service and selected output format. The NCEDC offers the following web services that are compliant with the International Federation of Digital Seismograph Networks (FDSN) web services specifications: (1) fdsn-dataselect: time series data delivered in MiniSEED format, (2) fdsn-station: station and channel metadata and time series availability delivered in StationXML format, (3) fdsn-event: earthquake event information delivered in QuakeML format. In addition, the NCEDC offers the the following IRIS-compatible web services: (1) sacpz: provide channel gains, poles, and zeros in SAC format, (2) resp: provide channel response information in RESP format, (3) dataless: provide station and channel metadata in Dataless SEED format. The NCEDC is also developing a web service to deliver timeseries from pre-assembled event waveform gathers. The NCEDC has waveform gathers for ~750,000 northern and central California events from 1984 to the present, many of which were created by the USGS NCSN prior to the establishment of the joint NCSS (Northern California Seismic System). We are currently adding waveforms to these older event gathers with time series from the UCB networks and other networks with waveforms archived at the NCEDC, and ensuring that the waveform for each channel in the event gathers have the highest

Modified Mercalli intensity assignments for the May 16, 1909, Northern Plains earthquake

USGS Publications Warehouse

Bakun, W.H.; Stickney, M.C.; Rogers, G.; Ristau, J.

2010-01-01

We use newspaper accounts from the United States and Canada to assign modified Mercalli intensity (MMI) at 90 towns for the May 16, 1909 Northern Plains earthquake. Our MMI assignments generally are consistent with those plotted on Nuttli's (1976) isoseiemal map. The earthquake was felt over more than 1,500,000 km2 in the states of Minnesota, Montana, North Dakota, South Dakota, and Wyoming and the provinces of Alberta, Manitoba, Ontario, and Saskatchewan.

Reducing Vulnerability of Ports and Harbors to Earthquake and Tsunami Hazards

USGS Publications Warehouse

Wood, Nathan J.; Good, James W.; Goodwin, Robert F.

2002-01-01

Recent scientific research suggests the Pacific Northwest could experience catastrophic earthquakes in the near future, both from distant and local sources, posing a significant threat to coastal communities. Damage could result from numerous earthquake-related hazards, such as severe ground shaking, soil liquefaction, landslides, land subsidence/uplift, and tsunami inundation. Because of their geographic location, ports and harbors are especially vulnerable to these hazards. Ports and harbors, however, are important components of many coastal communities, supporting numerous activities critical to the local and regional economy and possibly serving as vital post-event, response-recovery transportation links. A collaborative, multi-year initiative is underway to increase the resiliency of Pacific Northwest ports and harbors to earthquake and tsunami hazards, involving Oregon Sea Grant (OSG), Washington Sea Grant (WSG), the National Oceanic and Atmospheric Administration Coastal Services Center (CSC), and the U.S. Geological Survey Center for Science Policy (CSP). Specific products of this research, planning, and outreach initiative include a regional stakeholder issues and needs assessment, a community-based mitigation planning process, a Geographic Information System (GIS) — based vulnerability assessment methodology, an educational web-site and a regional data archive. This paper summarizes these efforts, including results of two pilot port-harbor community projects, one in Yaquina Bay, Oregon and the other in Sinclair Inlet, Washington. Finally, plans are outlined for outreach to other port and harbor communities in the Pacific Northwest and beyond, using "getting started" workshops and a web-based tutorial.

Seismo-Tectonics of the 2014 Chiang Rai, Thailand, Earthquake Sequence

NASA Astrophysics Data System (ADS)

Furlong, K. P.; Pananont, P.; Herman, M. W.; Waldhauser, F.; Pornsopin, P.; Warnitchai, P.; Kosuwan, S.

2016-12-01

On 5 May 2014, a Mw 6.2 strike-slip earthquake struck in the Mae Lao region of Chiang Rai province in Thailand. This earthquake occurred in a region of known faults, but identified as relatively low earthquake hazard, and caused substantial damage and injuries. Detailed field reconnaissance and deployment of a dense, temporary seismometer network allowed details of the damage and its relationship to seismicity to be analyzed. The aftershock sequence associated with this mainshock occurs on two well-defined trends, reflecting the two potential fault planes in earthquake focal mechanisms for the mainshock and the majority of the aftershocks. The damage area was relatively large for an event of this magnitude, but primarily occurs within the primary rupture (aftershock) region or along regional rivers with soils susceptible to liquefaction of other ground failure. Stress modeling combined with the time-series and pattern of aftershock activity lead us to propose that the initial mainshock rupture continued slightly onto its conjugate faults near its northern termination, helping to trigger the distinct pattern of two discrete, conjugate trends of aftershock activity that mirror the kinematics of the mainshock fault mechanism. Although this earthquake occurred in a region of known faults, it cannot be directly linked to a previously mapped structure. This coupled with the substantial damage from the event indicates that there is potentially a higher earthquake hazard in northern and central Thailand than previously recognized.

2018 one‐year seismic hazard forecast for the central and eastern United States from induced and natural earthquakes

USGS Publications Warehouse

Petersen, Mark D.; Mueller, Charles; Moschetti, Morgan P.; Hoover, Susan M.; Rukstales, Kenneth S.; McNamara, Daniel E.; Williams, Robert A.; Shumway, Allison; Powers, Peter; Earle, Paul; Llenos, Andrea L.; Michael, Andrew J.; Rubinstein, Justin L.; Norbeck, Jack; Cochran, Elizabeth S.

2018-01-01

This article describes the U.S. Geological Survey (USGS) 2018 one‐year probabilistic seismic hazard forecast for the central and eastern United States from induced and natural earthquakes. For consistency, the updated 2018 forecast is developed using the same probabilistic seismicity‐based methodology as applied in the two previous forecasts. Rates of earthquakes across the United States M≥3.0">M≥3.0 grew rapidly between 2008 and 2015 but have steadily declined over the past 3 years, especially in areas of Oklahoma and southern Kansas where fluid injection has decreased. The seismicity pattern in 2017 was complex with earthquakes more spatially dispersed than in the previous years. Some areas of west‐central Oklahoma experienced increased activity rates where industrial activity increased. Earthquake rates in Oklahoma (429 earthquakes of M≥3">M≥3 and 4 M≥4">M≥4), Raton basin (Colorado/New Mexico border, six earthquakes M≥3">M≥3), and the New Madrid seismic zone (11 earthquakes M≥3">M≥3) continue to be higher than historical levels. Almost all of these earthquakes occurred within the highest hazard regions of the 2017 forecast. Even though rates declined over the past 3 years, the short‐term hazard for damaging ground shaking across much of Oklahoma remains at high levels due to continuing high rates of smaller earthquakes that are still hundreds of times higher than at any time in the state’s history. Fine details and variability between the 2016–2018 forecasts are obscured by significant uncertainties in the input model. These short‐term hazard levels are similar to active regions in California. During 2017, M≥3">M≥3 earthquakes also occurred in or near Ohio, West Virginia, Missouri, Kentucky, Tennessee, Arkansas, Illinois, Oklahoma, Kansas, Colorado, New Mexico, Utah, and Wyoming.

Seismic Hazard and risk assessment for Romania -Bulgaria cross-border region

NASA Astrophysics Data System (ADS)

Simeonova, Stela; Solakov, Dimcho; Alexandrova, Irena; Vaseva, Elena; Trifonova, Petya; Raykova, Plamena

2016-04-01

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 hazard and vulnerability to earthquakes are steadily increasing as urbanization and development occupy more areas that are prone to effects of strong earthquakes. The assessment of the seismic hazard and risk is particularly important, because it provides valuable information for seismic safety and disaster mitigation, and it supports decision making for the benefit of society. Romania and Bulgaria, situated in the Balkan Region as a part of the Alpine-Himalayan seismic belt, are characterized by high seismicity, and are exposed to a high seismic risk. Over the centuries, both countries have experienced strong earthquakes. The cross-border region encompassing the northern Bulgaria and southern Romania is a territory prone to effects of strong earthquakes. The area is significantly affected by earthquakes occurred in both countries, on the one hand the events generated by the Vrancea intermediate-depth seismic source in Romania, and on the other hand by the crustal seismicity originated in the seismic sources: Shabla (SHB), Dulovo, Gorna Orjahovitza (GO) in Bulgaria. The Vrancea seismogenic zone of Romania is a very peculiar seismic source, often described as unique in the world, and it represents a major concern for most of the northern part of Bulgaria as well. In the present study the seismic hazard for Romania-Bulgaria cross-border region on the basis of integrated basic geo-datasets is assessed. The hazard results are obtained by applying two alternative approaches - probabilistic and deterministic. The MSK64 intensity (MSK64 scale is practically equal to the new EMS98) is used as output parameter for the hazard maps. We prefer to use here the macroseismic intensity instead of PGA, because it is directly related to the degree of damages and, moreover, the epicentral intensity is the original

Impact of earthquake source complexity and land elevation data resolution on tsunami hazard assessment and fatality estimation

NASA Astrophysics Data System (ADS)

Muhammad, Ario; Goda, Katsuichiro

2018-03-01

This study investigates the impact of model complexity in source characterization and digital elevation model (DEM) resolution on the accuracy of tsunami hazard assessment and fatality estimation through a case study in Padang, Indonesia. Two types of earthquake source models, i.e. complex and uniform slip models, are adopted by considering three resolutions of DEMs, i.e. 150 m, 50 m, and 10 m. For each of the three grid resolutions, 300 complex source models are generated using new statistical prediction models of earthquake source parameters developed from extensive finite-fault models of past subduction earthquakes, whilst 100 uniform slip models are constructed with variable fault geometry without slip heterogeneity. The results highlight that significant changes to tsunami hazard and fatality estimates are observed with regard to earthquake source complexity and grid resolution. Coarse resolution (i.e. 150 m) leads to inaccurate tsunami hazard prediction and fatality estimation, whilst 50-m and 10-m resolutions produce similar results. However, velocity and momentum flux are sensitive to the grid resolution and hence, at least 10-m grid resolution needs to be implemented when considering flow-based parameters for tsunami hazard and risk assessments. In addition, the results indicate that the tsunami hazard parameters and fatality number are more sensitive to the complexity of earthquake source characterization than the grid resolution. Thus, the uniform models are not recommended for probabilistic tsunami hazard and risk assessments. Finally, the findings confirm that uncertainties of tsunami hazard level and fatality in terms of depth, velocity and momentum flux can be captured and visualized through the complex source modeling approach. From tsunami risk management perspectives, this indeed creates big data, which are useful for making effective and robust decisions.

The Southern California Earthquake Survival Program

USGS Publications Warehouse

Harris, J.M.

1989-01-01

In July 1988, the Los Angeles County Board of Supervisors directed the Chief Administrative Office to develop an educational program aimed at improving earthquake preparedness among Los Angeles County residents. the board recognized that current earthquake education efforts were not only insufficient, but also often confusing and costly. The board unanimously approved the development of a program that would make earthquake preparedness a year-long effort by encouraging residents to take a different precaution each month. 

Probabilistic tsunami hazard assessment based on the long-term evaluation of subduction-zone earthquakes along the Sagami Trough, Japan

NASA Astrophysics Data System (ADS)

Hirata, K.; Fujiwara, H.; Nakamura, H.; Osada, M.; Ohsumi, T.; Morikawa, N.; Kawai, S.; Maeda, T.; Matsuyama, H.; Toyama, N.; Kito, T.; Murata, Y.; Saito, R.; Takayama, J.; Akiyama, S.; Korenaga, M.; Abe, Y.; Hashimoto, N.; Hakamata, T.

2017-12-01

For the forthcoming large earthquakes along the Sagami Trough where the Philippine Sea Plate is subducting beneath the northeast Japan arc, the Earthquake Research Committee(ERC) /Headquarters for Earthquake Research Promotion, Japanese government (2014a) assessed that M7 and M8 class earthquakes will occur there and defined the possible extent of the earthquake source areas. They assessed 70% and 0% 5% of the occurrence probability within the next 30 years (from Jan. 1, 2014), respectively, for the M7 and M8 class earthquakes. First, we set possible 10 earthquake source areas(ESAs) and 920 ESAs, respectively, for M8 and M7 class earthquakes. Next, we constructed 125 characterized earthquake fault models (CEFMs) and 938 CEFMs, respectively, for M8 and M7 class earthquakes, based on "tsunami receipt" of ERC (2017) (Kitoh et al., 2016, JpGU). All the CEFMs are allowed to have a large slip area for expression of fault slip heterogeneity. For all the CEFMs, we calculate tsunamis by solving a nonlinear long wave equation, using FDM, including runup calculation, over a nesting grid system with a minimum grid size of 50 meters. Finally, we re-distributed the occurrence probability to all CEFMs (Abe et al., 2014, JpGU) and gathered excess probabilities for variable tsunami heights, calculated from all the CEFMs, at every observation point along Pacific coast to get PTHA. We incorporated aleatory uncertainties inherent in tsunami calculation and earthquake fault slip heterogeneity. We considered two kinds of probabilistic hazard models; one is "Present-time hazard model" under an assumption that the earthquake occurrence basically follows a renewal process based on BPT distribution if the latest faulting time was known. The other is "Long-time averaged hazard model" under an assumption that earthquake occurrence follows a stationary Poisson process. We fixed our viewpoint, for example, on the probability that the tsunami height will exceed 3 meters at coastal points in next

Rupture directivity of moderate earthquakes in northern California

USGS Publications Warehouse

Seekins, Linda C.; Boatwright, John

2010-01-01

We invert peak ground velocity and acceleration (PGV and PGA) to estimate rupture direction and rupture velocity for 47 moderate earthquakes (3.5≥M≥5.4) in northern California. We correct sets of PGAs and PGVs recorded at stations less than 55–125 km, depending on source depth, for site amplification and source–receiver distance, then fit the residual peak motions to the unilateral directivity function of Ben-Menahem (1961). We independently invert PGA and PGV. The rupture direction can be determined using as few as seven peak motions if the station distribution is sufficient. The rupture velocity is unstable, however, if there are no takeoff angles within 30° of the rupture direction. Rupture velocities are generally subsonic (0.5β–0.9β); for stability, we limit the rupture velocity at v=0.92β, the Rayleigh wave speed. For 73 of 94 inversions, the rupture direction clearly identifies one of the nodal planes as the fault plane. The 35 strike-slip earthquakes have rupture directions that range from nearly horizontal (6 events) to directly updip (5 events); the other 24 rupture partly along strike and partly updip. Two strike-slip earthquakes rupture updip in one inversion and downdip in the other. All but 1 of the 11 thrust earthquakes rupture predominantly updip. We compare the rupture directions for 10 M≥4.0 earthquakes to the relative location of the mainshock and the first two weeks of aftershocks. Spatial distributions of 8 of 10 aftershock sequences agree well with the rupture directivity calculated for the mainshock.

Impact of Short-term Changes In Earthquake Hazard on Risk In Christchurch, New Zealand

NASA Astrophysics Data System (ADS)

Nyst, M.

2012-12-01

The recent Mw 7.1, 4 September 2010 Darfield, and Mw 6.2, 22 February 2011 Christchurch, New Zealand earthquakes and the following aftershock activity completely changed the existing view on earthquake hazard of the Christchurch area. Not only have several faults been added to the New Zealand fault database, the main shocks were also followed by significant increases in seismicity due to high aftershock activity throughout the Christchurch region that is still on-going. Probabilistic seismic hazard assessment (PSHA) models take into account a stochastic event set, the full range of possible events that can cause damage or loss at a particular location. This allows insurance companies to look at their risk profiles via average annual losses (AAL) and loss-exceedance curves. The loss-exceedance curve is derived from the full suite of seismic events that could impact the insured exposure and plots the probability of exceeding a particular loss level over a certain period. Insurers manage their risk by focusing on a certain return period exceedance benchmark, typically between the 100 and 250 year return period loss level, and then reserve the amount of money needed to account for that return period loss level, their so called capacity. This component of risk management is not too sensitive to short-term changes in risk due to aftershock seismicity, as it is mostly dominated by longer-return period, larger magnitude, more damaging events. However, because the secondairy uncertainties are taken into account when calculating the exceedance probability, even the longer return period losses can still experience significant impact from the inclusion of time-dependent earthquake behavior. AAL is calculated by summing the product of the expected loss level and the annual rate for all events in the event set that cause damage or loss at a particular location. This relatively simple metric is an important factor in setting the annual premiums. By annualizing the expected losses

The Cascadia Subduction Zone and related subduction systems: seismic structure, intraslab earthquakes and processes, and earthquake hazards

USGS Publications Warehouse

Kirby, Stephen H.; Wang, Kelin; Dunlop, Susan

2002-01-01

The following report is the principal product of an international workshop titled “Intraslab Earthquakes in the Cascadia Subduction System: Science and Hazards” and was sponsored by the U.S. Geological Survey, the Geological Survey of Canada and the University of Victoria. This meeting was held at the University of Victoria’s Dunsmuir Lodge, Vancouver Island, British Columbia, Canada on September 18–21, 2000 and brought 46 participants from the U.S., Canada, Latin America and Japan. This gathering was organized to bring together active research investigators in the science of subduction and intraslab earthquake hazards. Special emphasis was given to “warm-slab” subduction systems, i.e., those systems involving young oceanic lithosphere subducting at moderate to slow rates, such as the Cascadia system in the U.S. and Canada, and the Nankai system in Japan. All the speakers and poster presenters provided abstracts of their presentations that were a made available in an abstract volume at the workshop. Most of the authors subsequently provided full articles or extended abstracts for this volume on the topics that they discussed at the workshop. Where updated versions were not provided, the original workshop abstracts have been included. By organizing this workshop and assembling this volume, our aim is to provide a global perspective on the science of warm-slab subduction, to thereby advance our understanding of internal slab processes and to use this understanding to improve appraisals of the hazards associated with large intraslab earthquakes in the Cascadia system. These events have been the most frequent and damaging earthquakes in western Washington State over the last century. As if to underscore this fact, just six months after this workshop was held, the magnitude 6.8 Nisqually earthquake occurred on February 28th, 2001 at a depth of about 55 km in the Juan de Fuca slab beneath the southern Puget Sound region of western Washington. The Governor�

Oklahoma experiences largest earthquake during ongoing regional wastewater injection hazard mitigation efforts

USGS Publications Warehouse

Yeck, William; Hayes, Gavin; McNamara, Daniel E.; Rubinstein, Justin L.; Barnhart, William; Earle, Paul; Benz, Harley M.

2017-01-01

The 3 September 2016, Mw 5.8 Pawnee earthquake was the largest recorded earthquake in the state of Oklahoma. Seismic and geodetic observations of the Pawnee sequence, including precise hypocenter locations and moment tensor modeling, shows that the Pawnee earthquake occurred on a previously unknown left-lateral strike-slip basement fault that intersects the mapped right-lateral Labette fault zone. The Pawnee earthquake is part of an unprecedented increase in the earthquake rate in Oklahoma that is largely considered the result of the deep injection of waste fluids from oil and gas production. If this is, indeed, the case for the M5.8 Pawnee earthquake, then this would be the largest event to have been induced by fluid injection. Since 2015, Oklahoma has undergone wide-scale mitigation efforts primarily aimed at reducing injection volumes. Thus far in 2016, the rate of M3 and greater earthquakes has decreased as compared to 2015, while the cumulative moment—or energy released from earthquakes—has increased. This highlights the difficulty in earthquake hazard mitigation efforts given the poorly understood long-term diffusive effects of wastewater injection and their connection to seismicity.

Earthquake induced landslide hazard field observatory in the Avcilar peninsula

NASA Astrophysics Data System (ADS)

Bigarre, Pascal; Coccia, Stella; Theoleyre, Fiona; Ergintav, Semih; Özel, Oguz; Yalçinkaya, Esref; Lenti, Luca; Martino, Salvatore; Gamba, Paolo; Zucca, Francesco; Moro, Marco

2015-04-01

SAR temporal series has been undertaken, providing global but accurate Identification and characterization of gravitational phenomena covering the aera. Evaluation of the resolution and identification of landslide hazard-related features using space multispectral/hyperspectral image data has been realized. Profit has been gained from a vast drilling and geological - geotechnical survey program undertaken by the Istanbul Metropolitan Area, to get important data to complete the geological model of the landslide as well as one deep borehole to set up permanent instrumentation on a quite large slow landslide, fully encircled by a dense building environment. The selected landslide was instrumented in 2014 with a real-time observational system including GPS, rainfall, piezometer and seismic monitoring. Objective of this permanent monitoring system is three folds: first to detect and quantify interaction between seismic motion, rainfall and mass movement, building a database opened to the scientific community in the future, second to help to calibrate dynamic numerical geomechanical simulations intending to study the sensitivity to seismic loading, and last but not least. Last but not least important geophysical field work has been conducted to assess seismic site effects already noticed during the 1999 earthquake .Data, metadata and main results are from now progressively compiled and formatted for appropriate integration in the cloud monitoring infrastructure for data sharing.

Earthquake shaking hazard estimates and exposure changes in the conterminous United States

USGS Publications Warehouse

Jaiswal, Kishor S.; Petersen, Mark D.; Rukstales, Kenneth S.; Leith, William S.

2015-01-01

A large portion of the population of the United States lives in areas vulnerable to earthquake hazards. This investigation aims to quantify population and infrastructure exposure within the conterminous U.S. that are subjected to varying levels of earthquake ground motions by systematically analyzing the last four cycles of the U.S. Geological Survey's (USGS) National Seismic Hazard Models (published in 1996, 2002, 2008 and 2014). Using the 2013 LandScan data, we estimate the numbers of people who are exposed to potentially damaging ground motions (peak ground accelerations at or above 0.1g). At least 28 million (~9% of the total population) may experience 0.1g level of shaking at relatively frequent intervals (annual rate of 1 in 72 years or 50% probability of exceedance (PE) in 50 years), 57 million (~18% of the total population) may experience this level of shaking at moderately frequent intervals (annual rate of 1 in 475 years or 10% PE in 50 years), and 143 million (~46% of the total population) may experience such shaking at relatively infrequent intervals (annual rate of 1 in 2,475 years or 2% PE in 50 years). We also show that there is a significant number of critical infrastructure facilities located in high earthquake-hazard areas (Modified Mercalli Intensity ≥ VII with moderately frequent recurrence interval).

San Andreas fault geometry at Desert Hot Springs, California, and its effects on earthquake hazards and groundwater

USGS Publications Warehouse

Catchings, R.D.; Rymer, M.J.; Goldman, M.R.; Gandhok, G.

2009-01-01

The Mission Creek and Banning faults are two of the principal strands of the San Andreas fault zone in the northern Coachella Valley of southern California. Structural characteristics of the faults affect both regional earthquake hazards and local groundwater resources. We use seismic, gravity, and geological data to characterize the San Andreas fault zone in the vicinity of Desert Hot Springs. Seismic images of the upper 500 m of the Mission Creek fault at Desert Hot Springs show multiple fault strands distributed over a 500 m wide zone, with concentrated faulting within a central 200 m wide area of the fault zone. High-velocity (up to 5000 m=sec) rocks on the northeast side of the fault are juxtaposed against a low-velocity (6.0) earthquakes in the area (in 1948 and 1986) occurred at or near the depths (~10 to 12 km) of the merged (San Andreas) fault. Large-magnitude earthquakes that nucleate at or below the merged fault will likely generate strong shaking from guided waves along both fault zones and from amplified seismic waves in the low-velocity basin between the two fault zones. The Mission Creek fault zone is a groundwater barrier with the top of the water table varying by 60 m in depth and the aquifer varying by about 50 m in thickness across a 200 m wide zone of concentrated faulting.

Marine and land active-source seismic investigation of geothermal potential, tectonic structure, and earthquake hazards in Pyramid Lake, Nevada

NASA Astrophysics Data System (ADS)

Eisses, A.; Kell, A. M.; Kent, G.; Driscoll, N. W.; Karlin, R. E.; Baskin, R. L.; Louie, J. N.; Smith, K. D.; Pullammanappallil, S.

2011-12-01

Preliminary slip rates measured across the East Pyramid Lake fault, or the Lake Range fault, help provide new estimates of extension across the Pyramid Lake basin. Multiple stratigraphic horizons spanning 48 ka were tracked throughout the lake, with layer offsets measured across all significant faults in the basin. A chronstratigraphic framework acquired from four sediment cores allows slip rates of the Lake Range and other faults to be calculated accurately. This region of the northern Walker Lake, strategically placed between the right-lateral strike-slip faults of Honey and Eagle Lakes to the north, and the normal fault bounded basins to the southwest (e.g., Tahoe, Carson), is critical in understanding the underlying structural complexity that is not only necessary for geothermal exploration, but also earthquake hazard assessment due to the proximity of the Reno-Sparks metropolitan area. In addition, our seismic CHIRP imaging with submeter resolution allows the construction of the first fault map of Pyramid Lake. The Lake Range fault can be obviously traced west of Anahoe Island extending north along the east end of the lake in numerous CHIRP lines. Initial drafts of the fault map reveal active transtension through a series of numerous, small, northwest striking, oblique-slip faults in the north end of the lake. A previously field mapped northwest striking fault near Sutcliff can be extended into the west end of Pyramid Lake. This fault map, along with the calculated slip rate of the Lake Range, and potentially multiple other faults, gives a clearer picture into understanding the geothermal potential, tectonic regime and earthquake hazards in the Pyramid Lake basin and the northern Walker Lane. These new results have also been merged with seismicity maps, along with focal mechanisms for the larger events to begin to extend our fault map in depth.

Probabilistic Tsunami Hazard Assessment along Nankai Trough (1) An assessment based on the information of the forthcoming earthquake that Earthquake Research Committee(2013) evaluated

NASA Astrophysics Data System (ADS)

Hirata, K.; Fujiwara, H.; Nakamura, H.; Osada, M.; Morikawa, N.; Kawai, S.; Ohsumi, T.; Aoi, S.; Yamamoto, N.; Matsuyama, H.; Toyama, N.; Kito, T.; Murashima, Y.; Murata, Y.; Inoue, T.; Saito, R.; Takayama, J.; Akiyama, S.; Korenaga, M.; Abe, Y.; Hashimoto, N.

2015-12-01

The Earthquake Research Committee(ERC)/HERP, Government of Japan (2013) revised their long-term evaluation of the forthcoming large earthquake along the Nankai Trough; the next earthquake is estimated M8 to 9 class, and the probability (P30) that the next earthquake will occur within the next 30 years (from Jan. 1, 2013) is 60% to 70%. In this study, we assess tsunami hazards (maximum coastal tsunami heights) in the near future, in terms of a probabilistic approach, from the next earthquake along Nankai Trough, on the basis of ERC(2013)'s report. The probabilistic tsunami hazard assessment that we applied is as follows; (1) Characterized earthquake fault models (CEFMs) are constructed on each of the 15 hypothetical source areas (HSA) that ERC(2013) showed. The characterization rule follows Toyama et al.(2015, JpGU). As results, we obtained total of 1441 CEFMs. (2) We calculate tsunamis due to CEFMs by solving nonlinear, finite-amplitude, long-wave equations with advection and bottom friction terms by finite-difference method. Run-up computation on land is included. (3) A time predictable model predicts the recurrent interval of the present seismic cycle is T=88.2 years (ERC,2013). We fix P30 = 67% by applying the renewal process based on BPT distribution with T and alpha=0.24 as its aperiodicity. (4) We divide the probability P30 into P30(i) for i-th subgroup consisting of the earthquakes occurring in each of 15 HSA by following a probability re-distribution concept (ERC,2014). Then each earthquake (CEFM) in i-th subgroup is assigned a probability P30(i)/N where N is the number of CEFMs in each sub-group. Note that such re-distribution concept of the probability is nothing but tentative because the present seismology cannot give deep knowledge enough to do it. Epistemic logic-tree approach may be required in future. (5) We synthesize a number of tsunami hazard curves at every evaluation points on coasts by integrating the information about 30 years occurrence

The U.S. Earthquake Prediction Program

USGS Publications Warehouse

Wesson, R.L.; Filson, J.R.

1981-01-01

There are two distinct motivations for earthquake prediction. The mechanistic approach aims to understand the processes leading to a large earthquake. The empirical approach is governed by the immediate need to protect lives and property. With our current lack of knowledge about the earthquake process, future progress cannot be made without gathering a large body of measurements. These are required not only for the empirical prediction of earthquakes, but also for the testing and development of hypotheses that further our understanding of the processes at work. The earthquake prediction program is basically a program of scientific inquiry, but one which is motivated by social, political, economic, and scientific reasons. It is a pursuit that cannot rely on empirical observations alone nor can it carried out solely on a blackboard or in a laboratory. Experiments must be carried out in the real Earth. 

Investigating Environmental Tectonics in Northern Alpine Foreland of Europe

NASA Astrophysics Data System (ADS)

Cloetingh, Sierd; Ziegler, Peter; Cornu, Tristan; Ustaszewski, K.; Schmid, S.; Dezes, P.; Hinsch, R.; Decker, K.; Lopes Cardozo, G.; Granet, M.; Bertrand, G.; Behrmann, J.; Michon, L.; Pagnier, H.; van Wees, J. D.; Rozsa, S.; Heck, B.; Verdun, J.; Kahle, H. G.; Fracassi, U.; Winter, T.; Burov, E.

Until now, research on neotectonics and related seismicity has mostly focused on active plate boundaries characterized by a generally high level of earthquake activity. Current seismic hazard estimates for intraplate areas are commonly based on probabilistic analyses of historical and instrumental earthquake data. The accuracy of these hazard estimates is limited by the nature of the data (e.g., ambiguous historical sources), and by the restriction of available earthquake catalogues to time scales of only few hundred years. Both of these are geologically insignificant and unsuitable for describing tectonic processes causing earthquakes. This is especially relevant to intraplate regions, where faults show low slip rates resulting in long average recurrence times for large earthquakes (103 to 106 yrs), such as the devastating Basel earthquake of 1356, with an estimated magnitude of 6.5. The Alpine orogen and the intraplate sedimentary basins and rifts of its northern foreland are associated with a much higher level of neotectonic activity than hitherto assumed. Seismicity and stress indicator data, combined with geodetic and geomorphologic observations, demonstrate that the Northern Alpine foreland is being actively deformed [Cloetingh, 2000; Ziegler et al., 2002; Behrmann et al., 2003]. This has major implications for the assessment of their natural hazards and environmental degradation. The northwest European lithosphere has undergone a polyphase evolution, in which the interplay between upper mantle thermal perturbations [Goes et al., 2000; Ritter et al., 2001] and stress-induced intraplate deformation [Muller et al., 1992; Ziegler et al., 2002] played an important role. A number of recent findings point to an important role of lithospheric folding in thermally weakened lithosphere of the northwestern European foreland [Cloetingh et al., 1999].

Imaging and Understanding Foreshock and Aftershock Behavior Around the 2014 Iquique, Northern Chile, Earthquake

NASA Astrophysics Data System (ADS)

Yang, H.; Meng, X.; Peng, Z.; Newman, A. V.; Hu, S.; Williamson, A.

2014-12-01

On April 1st, 2014, a moment magnitude (MW) 8.2 earthquake occurred offshore Iquique, Northern Chile. There were numerous smaller earthquakes preceding and following the mainshock, making it an ideal case to study the spatio-temporal relation among these events and their association with the mainshock. We applied a matched-filter technique to detect previously missing foreshocks and aftershocks of the 2014 Iquique earthquake. Using more than 900 template events recorded by 19 broadband seismic stations (network code CX) operated by the GEOFON Program of GFZ Potsdam, we found 4392 earthquakes between March 1st and April 3rd, 2014, including more than 30 earthquakes with magnitude larger than 4 that were previously missed in the catalog from the Chile National Seismological Center. Additionally, we found numerous small earthquakes with magnitudes between 1 and 2 preceding the largest foreshock, an MW 6.7 event occurring on March 16th, approximately 2 weeks before the Iquique mainshock. We observed that the foreshocks migrated northward at a speed of approximately 6 km/day. Using a finite fault slip model of the mainshock determined from teleseismic waveform inversion (Hayes, 2014), we calculated the Coulomb stress changes in the nearby regions of the mainshock. We found that there was ~200% increase in seismicity in the areas with increased Coulomb stress. Our next step is to evaluate the Coulomb stress changes associated with earlier foreshocks and their roles in triggering later foreshocks, and possibly the mainshock. For this, we plan to create a fault model of the temporal evolution of the Coulomb behavior along the interface with time, assuming Wells and Coppersmith (1994) type fault parameters. These results will be compared with double-difference relocations (using HypoDD), presenting a more accurate understanding of the spatial-temporal evolution of foreshocks and aftershocks of the 2014 Iquique earthquake.

Surface rupture and vertical deformation associated with 20 May 2016 M6 Petermann Ranges earthquake, Northern Territory, Australia

NASA Astrophysics Data System (ADS)

Gold, Ryan; Clark, Dan; King, Tamarah; Quigley, Mark

2017-04-01

Surface-rupturing earthquakes in stable continental regions (SCRs) occur infrequently, though when they occur in heavily populated regions the damage and loss of life can be severe (e.g., 2001 Bhuj earthquake). Quantifying the surface-rupture characteristics of these low-probability events is therefore important, both to improve understanding of the on- and off-fault deformation field near the rupture trace and to provide additional constraints on earthquake magnitude to rupture length and displacement, which are critical inputs for seismic hazard calculations. This investigation focuses on the 24 August 2016 M6.0 Petermann Ranges earthquake, Northern Territory, Australia. We use 0.3-0.5 m high-resolution optical Worldview satellite imagery to map the trace of the surface rupture associated with the earthquake. From our mapping, we are able to trace the rupture over a length of 20 km, trending NW, and exhibiting apparent north-side-up motion. To quantify the magnitude of vertical surface deformation, we use stereo Worldview images processed using NASA Ames Stereo Pipeline software to generate pre- and post-earthquake digital terrain models with a spatial resolution of 1.5 to 2 m. The surface scarp is apparent in much of the post-event digital terrain model. Initial efforts to difference the pre- and post-event digital terrain models yield noisy results, though we detect vertical deformation of 0.2 to 0.6 m over length scales of 100 m to 1 km from the mapped trace of the rupture. Ongoing efforts to remove ramps and perform spatial smoothing will improve our understanding of the extent and pattern of vertical deformation. Additionally, we will compare our results with InSAR and field measurements obtained following the earthquake.

EFEHR - the European Facilities for Earthquake Hazard and Risk: beyond the web-platform

NASA Astrophysics Data System (ADS)

Danciu, Laurentiu; Wiemer, Stefan; Haslinger, Florian; Kastli, Philipp; Giardini, Domenico

2017-04-01

European Facilities for Earthquake Hazard and Risk (EEFEHR) represents the sustainable community resource for seismic hazard and risk in Europe. The EFEHR web platform is the main gateway to access data, models and tools as well as provide expertise relevant for assessment of seismic hazard and risk. The main services (databases and web-platform) are hosted at ETH Zurich and operated by the Swiss Seismological Service (Schweizerischer Erdbebendienst SED). EFEHR web-portal (www.efehr.org) collects and displays (i) harmonized datasets necessary for hazard and risk modeling, e.g. seismic catalogues, fault compilations, site amplifications, vulnerabilities, inventories; (ii) extensive seismic hazard products, namely hazard curves, uniform hazard spectra and maps for national and regional assessments. (ii) standardized configuration files for re-computing the regional seismic hazard models; (iv) relevant documentation of harmonized datasets, models and web-services. Today, EFEHR distributes full output of the 2013 European Seismic Hazard Model, ESHM13, as developed within the SHARE project (http://www.share-eu.org/); the latest results of the 2014 Earthquake Model of the Middle East (EMME14), derived within the EMME Project (www.emme-gem.org); the 2001 Global Seismic Hazard Assessment Project (GSHAP) results and the 2015 updates of the Swiss Seismic Hazard. New datasets related to either seismic hazard or risk will be incorporated as they become available. We present the currents status of the EFEHR platform, with focus on the challenges, summaries of the up-to-date datasets, user experience and feedback, as well as the roadmap to future technological innovation beyond the web-platform development. We also show the new services foreseen to fully integrate with the seismological core services of European Plate Observing System (EPOS).

Tsunami hazard map in eastern Bali

NASA Astrophysics Data System (ADS)

Afif, Haunan; Cipta, Athanasius

2015-04-01

Bali is a popular tourist destination both for Indonesian and foreign visitors. However, Bali is located close to the collision zone between the Indo-Australian Plate and Eurasian Plate in the south and back-arc thrust off the northern coast of Bali resulted Bali prone to earthquake and tsunami. Tsunami hazard map is needed for better understanding of hazard level in a particular area and tsunami modeling is one of the most reliable techniques to produce hazard map. Tsunami modeling conducted using TUNAMI N2 and set for two tsunami sources scenarios which are subduction zone in the south of Bali and back thrust in the north of Bali. Tsunami hazard zone is divided into 3 zones, the first is a high hazard zones with inundation height of more than 3m. The second is a moderate hazard zone with inundation height 1 to 3m and the third is a low tsunami hazard zones with tsunami inundation heights less than 1m. Those 2 scenarios showed southern region has a greater potential of tsunami impact than the northern areas. This is obviously shown in the distribution of the inundated area in the south of Bali including the island of Nusa Penida, Nusa Lembongan and Nusa Ceningan is wider than in the northern coast of Bali although the northern region of the Nusa Penida Island more inundated due to the coastal topography.

Tsunami hazard map in eastern Bali

DOE Office of Scientific and Technical Information (OSTI.GOV)

Afif, Haunan, E-mail: afif@vsi.esdm.go.id; Cipta, Athanasius; Australian National University, Canberra

Bali is a popular tourist destination both for Indonesian and foreign visitors. However, Bali is located close to the collision zone between the Indo-Australian Plate and Eurasian Plate in the south and back-arc thrust off the northern coast of Bali resulted Bali prone to earthquake and tsunami. Tsunami hazard map is needed for better understanding of hazard level in a particular area and tsunami modeling is one of the most reliable techniques to produce hazard map. Tsunami modeling conducted using TUNAMI N2 and set for two tsunami sources scenarios which are subduction zone in the south of Bali and backmore » thrust in the north of Bali. Tsunami hazard zone is divided into 3 zones, the first is a high hazard zones with inundation height of more than 3m. The second is a moderate hazard zone with inundation height 1 to 3m and the third is a low tsunami hazard zones with tsunami inundation heights less than 1m. Those 2 scenarios showed southern region has a greater potential of tsunami impact than the northern areas. This is obviously shown in the distribution of the inundated area in the south of Bali including the island of Nusa Penida, Nusa Lembongan and Nusa Ceningan is wider than in the northern coast of Bali although the northern region of the Nusa Penida Island more inundated due to the coastal topography.« less

FORESHOCKS AND TIME-DEPENDENT EARTHQUAKE HAZARD ASSESSMENT IN SOUTHERN CALIFORNIA.

USGS Publications Warehouse

Jones, Lucile M.

1985-01-01

The probability that an earthquake in southern California (M greater than equivalent to 3. 0) will be followed by an earthquake of larger magnitude within 5 days and 10 km (i. e. , will be a foreshock) is 6 plus or minus 0. 5 per cent (1 S. D. ), and is not significantly dependent on the magnitude of the possible foreshock between M equals 3 and M equals 5. The probability that an earthquake will be followed by an M greater than equivalent to 5. 0 main shock, however, increases with magnitude of the foreshock from less than 1 per cent at M greater than equivalent to 3 to 6. 5 plus or minus 2. 5 per cent (1 S. D. ) at M greater than equivalent to 5. The main shock will most likely occur in the first hour after the foreshock, and the probability that a main shock will occur in the first hour decreases with elapsed time from the occurrence of the possible foreshock by approximately the inverse of time. Thus, the occurrence of an earthquake of M greater than equivalent to 3. 0 in southern California increases the earthquake hazard within a small space-time window several orders of magnitude above the normal background level.

The Effects of the Passage of Time from the 2011 Tohoku Earthquake on the Public's Anxiety about a Variety of Hazards.

PubMed

Nakayachi, Kazuya; Nagaya, Kazuhisa

2016-08-31

This research investigated whether the Japanese people's anxiety about a variety of hazards, including earthquakes and nuclear accidents, has changed over time since the Tohoku Earthquake in 2011. Data from three nationwide surveys conducted in 2008, 2012, and 2015 were compared to see the change in societal levels of anxiety toward 51 types of hazards. The same two-phase stratified random sampling method was used to create the list of participants in each survey. The results showed that anxiety about earthquakes and nuclear accidents had increased for a time after the Tohoku Earthquake, and then decreased after a four-year time frame with no severe earthquakes and nuclear accidents. It was also revealed that the anxiety level for some hazards other than earthquakes and nuclear accidents had decreased at ten months after the Earthquake, and then remained unchanged after the four years. Therefore, ironically, a major disaster might decrease the public anxiety in general at least for several years.

Echo-sounding method aids earthquake hazard studies

USGS Publications Warehouse

,

1995-01-01

Dramatic examples of catastrophic damage from an earthquake occurred in 1989, when the M 7.1 Lorna Prieta rocked the San Francisco Bay area, and in 1994, when the M 6.6 Northridge earthquake jolted southern California. The surprising amount and distribution of damage to private property and infrastructure emphasizes the importance of seismic-hazard research in urbanized areas, where the potential for damage and loss of life is greatest. During April 1995, a group of scientists from the U.S. Geological Survey and the University of Tennessee, using an echo-sounding method described below, is collecting data in San Antonio Park, California, to examine the Monte Vista fault which runs through this park. The Monte Vista fault in this vicinity shows evidence of movement within the last 10,000 years or so. The data will give them a "picture" of the subsurface rock deformation near this fault. The data will also be used to help locate a trench that will be dug across the fault by scientists from William Lettis & Associates.

Studying geodesy and earthquake hazard in and around the New Madrid Seismic Zone

USGS Publications Warehouse

Boyd, Oliver Salz; Magistrale, Harold

2011-01-01

Workshop on New Madrid Geodesy and the Challenges of Understanding Intraplate Earthquakes; Norwood, Massachusetts, 4 March 2011 Twenty-six researchers gathered for a workshop sponsored by the U.S. Geological Survey (USGS) and FM Global to discuss geodesy in and around the New Madrid seismic zone (NMSZ) and its relation to earthquake hazards. The group addressed the challenge of reconciling current geodetic measurements, which show low present-day surface strain rates, with paleoseismic evidence of recent, relatively frequent, major earthquakes in the region. The workshop presentations and conclusions will be available in a forthcoming USGS open-file report (http://pubs.usgs.gov).

Dynamic evaluation of seismic hazard and risks based on the Unified Scaling Law for Earthquakes

NASA Astrophysics Data System (ADS)

Kossobokov, V. G.; Nekrasova, A.

2016-12-01

We continue applying the general concept of seismic risk analysis in a number of seismic regions worldwide by constructing seismic hazard maps based on the Unified Scaling Law for Earthquakes (USLE), i.e. log N(M,L) = A + B•(6 - M) + C•log L, where N(M,L) is the expected annual number of earthquakes of a certain magnitude M within an seismically prone area of linear dimension L, A characterizes the average annual rate of strong (M = 6) earthquakes, B determines the balance between magnitude ranges, and C estimates the fractal dimension of seismic locus in projection to the Earth surface. The parameters A, B, and C of USLE are used to assess, first, the expected maximum magnitude in a time interval at a seismically prone cell of a uniform grid that cover the region of interest, and then the corresponding expected ground shaking parameters. After a rigorous testing against the available seismic evidences in the past (e.g., the historically reported macro-seismic intensity or paleo data), such a seismic hazard map is used to generate maps of specific earthquake risks for population, cities, and infrastructures. The hazard maps for a given territory change dramatically, when the methodology is applied to a certain size moving time window, e.g. about a decade long for an intermediate-term regional assessment or exponentially increasing intervals for a daily local strong aftershock forecasting. The of dynamical seismic hazard and risks assessment is illustrated by applications to the territory of Greater Caucasus and Crimea and the two-year series of aftershocks of the 11 October 2008 Kurchaloy, Chechnya earthquake which case-history appears to be encouraging for further systematic testing as potential short-term forecasting tool.

Disaggregated seismic hazard and the elastic input energy spectrum: An approach to design earthquake selection

NASA Astrophysics Data System (ADS)

Chapman, Martin Colby

1998-12-01

The design earthquake selection problem is fundamentally probabilistic. Disaggregation of a probabilistic model of the seismic hazard offers a rational and objective approach that can identify the most likely earthquake scenario(s) contributing to hazard. An ensemble of time series can be selected on the basis of the modal earthquakes derived from the disaggregation. This gives a useful time-domain realization of the seismic hazard, to the extent that a single motion parameter captures the important time-domain characteristics. A possible limitation to this approach arises because most currently available motion prediction models for peak ground motion or oscillator response are essentially independent of duration, and modal events derived using the peak motions for the analysis may not represent the optimal characterization of the hazard. The elastic input energy spectrum is an alternative to the elastic response spectrum for these types of analyses. The input energy combines the elements of amplitude and duration into a single parameter description of the ground motion that can be readily incorporated into standard probabilistic seismic hazard analysis methodology. This use of the elastic input energy spectrum is examined. Regression analysis is performed using strong motion data from Western North America and consistent data processing procedures for both the absolute input energy equivalent velocity, (Vsbea), and the elastic pseudo-relative velocity response (PSV) in the frequency range 0.5 to 10 Hz. The results show that the two parameters can be successfully fit with identical functional forms. The dependence of Vsbea and PSV upon (NEHRP) site classification is virtually identical. The variance of Vsbea is uniformly less than that of PSV, indicating that Vsbea can be predicted with slightly less uncertainty as a function of magnitude, distance and site classification. The effects of site class are important at frequencies less than a few Hertz. The regression

The Redwood Coast Tsunami Work Group: Promoting Earthquake and Tsunami Resilience on California's North Coast

NASA Astrophysics Data System (ADS)

Dengler, L. A.; Henderson, C.; Larkin, D.; Nicolini, T.; Ozaki, V.

2014-12-01

In historic times, Northern California has suffered the greatest losses from tsunamis in the U.S. contiguous 48 states. 39 tsunamis have been recorded in the region since 1933, including five that caused damage. This paper describes the Redwood Coast Tsunami Work Group (RCTWG), an organization formed in 1996 to address the tsunami threat from both near and far sources. It includes representatives from government agencies, public, private and volunteer organizations, academic institutions, and individuals interested in working to reduce tsunami risk. The geographic isolation and absence of scientific agencies such as the USGS and CGS in the region, and relatively frequent occurrence of both earthquakes and tsunami events has created a unique role for the RCTWG, with activities ranging from basic research to policy and education and outreach programs. Regional interest in tsunami issues began in the early 1990s when there was relatively little interest in tsunamis elsewhere in the state. As a result, the group pioneered tsunami messaging and outreach programs. Beginning in 2008, the RCTWG has partnered with the National Weather Service and the California Office of Emergency Services in conducting the annual "live code" tsunami communications tests, the only area outside of Alaska to do so. In 2009, the RCTWG joined with the Southern California Earthquake Alliance and the Bay Area Earthquake Alliance to form the Earthquake Country Alliance to promote a coordinated and consistent approach to both earthquake and tsunami preparedness throughout the state. The RCTWG has produced and promoted a variety of preparedness projects including hazard mapping and sign placement, an annual "Earthquake - Tsunami Room" at County Fairs, public service announcements and print material, assisting in TsunamiReady community recognition, and facilitating numerous multi-agency, multidiscipline coordinated exercises, and community evacuation drills. Nine assessment surveys from 1993 to 2013

Semi-automated landform classification for hazard mapping of soil liquefaction by earthquake

NASA Astrophysics Data System (ADS)

Nakano, Takayuki

2018-05-01

Soil liquefaction damages were caused by huge earthquake in Japan, and the similar damages are concerned in near future huge earthquake. On the other hand, a preparation of soil liquefaction risk map (soil liquefaction hazard map) is impeded by the difficulty of evaluation of soil liquefaction risk. Generally, relative soil liquefaction risk should be able to be evaluated from landform classification data by using experimental rule based on the relationship between extent of soil liquefaction damage and landform classification items associated with past earthquake. Therefore, I rearranged the relationship between landform classification items and soil liquefaction risk intelligibly in order to enable the evaluation of soil liquefaction risk based on landform classification data appropriately and efficiently. And I developed a new method of generating landform classification data of 50-m grid size from existing landform classification data of 250-m grid size by using digital elevation model (DEM) data and multi-band satellite image data in order to evaluate soil liquefaction risk in detail spatially. It is expected that the products of this study contribute to efficient producing of soil liquefaction hazard map by local government.

Persistency of rupture directivity in moderate-magnitude earthquakes in Italy: Implications for seismic hazard

NASA Astrophysics Data System (ADS)

Rovelli, A.; Calderoni, G.

2012-12-01

A simple method based on the EGF deconvolution in the frequency domain is applied to detect the occurrence of unilateral ruptures in recent damaging earthquakes in Italy. The spectral ratio between event pairs with different magnitudes at individual stations shows large azimuthal variations above corner frequency when the target event is affected by source directivity and the EGF is not or vice versa. The analysis is applied to seismograms and accelerograms recorded during the seismic sequence following the 20 May 2012, Mw 5.6 main shock in Emilia, northern Italy, the 6 April 2009, Mw 6.1 earthquake of L'Aquila, central Italy, and the 26 September 1997, Mw 5.7 and 6.0 shocks in Umbria-Marche, central Italy. Events of each seismic sequence are selected as having consistent focal mechanisms, and the station selection obeys to the constraint of a similar source-to-receiver path for the event pairs. The analyzed data set of L'Aquila consists of 962 broad-band seismograms relative to 69 normal-faulting earthquakes (3.3 ≤ MW ≤ 6.1, according to Herrmann et al., 2011), stations are selected in the distance range 100 to 250 km to minimize differences in propagation paths. The seismogram analysis reveals that a strong along-strike (toward SE) source directivity characterized all of the three Mw > 5.0 shocks. Source directivity was also persistent up to the smallest magnitudes: 65% of earthquakes under study showed evidence of directivity toward SE whereas only one (Mw 3.7) event showed directivity in the opposite direction. Also the Mw 5.6 main shock of the 20 May 2012 in Emilia result in large azimuthal spectral variations indicating unilateral rupture propagation toward SE. According to the reconstructed geometry of the trust-fault plane, the inferred directivity direction suggests top-down rupture propagation. The analysis over the Emilia aftershock sequence is in progress. The third seismic sequence, dated 1997-1998, occurred in the northern Apennines and, similarly

The Northern California Earthquake Management System: A Unified System From Realtime Monitoring to Data Distribution

NASA Astrophysics Data System (ADS)

Neuhauser, D.; Dietz, L.; Lombard, P.; Klein, F.; Zuzlewski, S.; Kohler, W.; Hellweg, M.; Luetgert, J.; Oppenheimer, D.; Romanowicz, B.

2006-12-01

The longstanding cooperation between the USGS Menlo Park and UC Berkeley's Seismological Laboratory for monitoring earthquakes and providing data to the research community is achieving a new level of integration. While station support and data collection for each network (NC, BK, BP) remain the responsibilities of the host institution, picks, codas and amplitudes will be produced and shared between the data centers continuously. Thus, realtime earthquake processing from triggering and locating through magnitude and moment tensor calculation and Shakemap production will take place independently at both locations, improving the robustness of event reporting in the Northern California Earthquake Management Center. Parametric data will also be exchanged with the Southern California Earthquake Management System to allow statewide earthquake detection and processing for further redundancy within the California Integrated Seismic Network (CISN). The database plays an integral part in this system, providing the coordination for event processing as well as the repository for event, instrument (metadata) and waveform information. The same master database serves both realtime processing, data quality control and archival, and the data center which provides waveforms and earthquake data to users in the research community. Continuous waveforms from all BK, BP, and NC stations, event waveform gathers, and event information automatically become available at the Northern California Earthquake Data Center (NCEDC). Currently, the NCEDC is collecting and makes available over 4 TByes of data per year from the NCEMC stations and other seismic networks, as well as from GPS and and other geophysical instrumentation.

Earthquake and Tsunami planning, outreach and awareness in Humboldt County, California

NASA Astrophysics Data System (ADS)

Ozaki, V.; Nicolini, T.; Larkin, D.; Dengler, L.

2008-12-01

Humboldt County has the longest coastline in California and is one of the most seismically active areas of the state. It is at risk from earthquakes located on and offshore and from tsunamis generated locally from faults associated with the Cascadia subduction zone (CSZ), other regional fault systems, and from distant sources elsewhere in the Pacific. In 1995 the California Division of Mines and Geology published the first earthquake scenario to include both strong ground shaking effects and a tsunami. As a result of the scenario, the Redwood Coast Tsunami Work Group (RCTWG), an organization of representatives from government agencies, tribes, service groups, academia and the private sector from the three northern coastal California counties, was formed in 1996 to coordinate and promote earthquake and tsunami hazard awareness and mitigation. The RCTWG and its member agencies have sponsored a variety of projects including education/outreach products and programs, tsunami hazard mapping, signage and siren planning, and has sponsored an Earthquake - Tsunami Education Room at the Humboldt County fair for the past eleven years. Three editions of Living on Shaky Ground an earthquake-tsunami preparedness magazine for California's North Coast, have been published since 1993 and a fourth is due to be published in fall 2008. In 2007, Humboldt County was the first region in the country to participate in a tsunami training exercise at FEMA's Emergency Management Institute in Emmitsburg, MD and the first area in California to conduct a full-scale tsunami evacuation drill. The County has conducted numerous multi-agency, multi-discipline coordinated exercises using county-wide tsunami response plan. Two Humboldt County communities were recognized as TsunamiReady by the National Weather Service in 2007. Over 300 tsunami hazard zone signs have been posted in Humboldt County since March 2008. Six assessment surveys from 1993 to 2006 have tracked preparedness actions and personal

Seismic Landslide Hazard for the City of Berkeley, California

USGS Publications Warehouse

Miles, Scott B.; Keefer, David K.

2001-01-01

This map describes the possible hazard from earthquake-induced landslides for the city of Berkeley, CA. The hazard depicted by this map was modeled for a scenario corresponding to an M=7.1 earthquake on the Hayward, CA fault. This scenario magnitude is associated with complete rupture of the northern and southern segments of the Hayward fault, an event that has an estimated return period of about 500 years. The modeled hazard also corresponds to completely saturated ground-water conditions resulting from an extreme storm event or series of storm events. This combination of earthquake and ground-water scenarios represents a particularly severe state of hazard for earthquake-induced landslides. For dry ground-water conditions, overall hazard will be less, while relative patterns of hazard are likely to change. Purpose: The map is intended as a tool for regional planning. Any site-specific planning or analysis should be undertaken with the assistance of a qualified geotechnical engineer. This hazard map should not be used as a substitute to the State of California Seismic Hazard Zones map for the same area. (See California Department of Conservation, Division of Mines and Geology, 1999). As previously noted for maps of this type by Wieczorek and others (1985), this map should not be used as a basis to determine the absolute risk from seismically triggered landslides at any locality, as the sole justification for zoning or rezoning any parcel, for detailed design of any lifeline, for site-specific hazard-reduction planning, or for setting or modifying insurance rates.

Earthquake induced landslide hazard: a multidisciplinary field observatory in the Marmara SUPERSITE

NASA Astrophysics Data System (ADS)

Bigarré, Pascal

2014-05-01

Earthquake-triggered landslides have an increasing disastrous impact in seismic regions due to the fast growing urbanization and infrastructures. Just considering disasters from the last fifteen years, among which the 1999 Chi-Chi earthquake, the 2008 Wenchuan earthquake, and the 2011 Tohoku earthquake, these events generated tens of thousands of coseismic landslides. Those resulted in amazing death toll and considerable damages, affecting the regional landscape including its hydrological main features. Despite a strong impetus in research during past decades, knowledge on those geohazards is still fragmentary, while databases of high quality observational data are lacking. These phenomena call for further collaborative researches aiming eventually to enhance preparedness and crisis management. As one of the three SUPERSITE concept FP7 projects dealing with long term high level monitoring of major natural hazards at the European level, the MARSITE project gathers research groups in a comprehensive monitoring activity developed in the Sea of Marmara Region, one of the most densely populated parts of Europe and rated at high seismic risk level since the 1999 Izmit and Duzce devastating earthquakes. Besides the seismic threat, landslides in Turkey and in this region constitute an important source of loss. The 1999 Earthquake caused extensive landslides while tsunami effects were observed during the post-event surveys in several places along the coasts of the Izmit bay. The 6th Work Package of MARSITE project gathers 9 research groups to study earthquake-induced landslides focusing on two sub-regional areas of high interest. First, the Cekmece-Avcilar peninsula, located westwards of Istanbul, is a highly urbanized concentrated landslide prone area, showing high susceptibility to both rainfalls while affected by very significant seismic site effects. Second, the off-shore entrance of the Izmit Gulf, close to the termination of the surface rupture of the 1999 earthquake

Neo-deterministic definition of earthquake hazard scenarios: a multiscale application to India

NASA Astrophysics Data System (ADS)

Peresan, Antonella; Magrin, Andrea; Parvez, Imtiyaz A.; Rastogi, Bal K.; Vaccari, Franco; Cozzini, Stefano; Bisignano, Davide; Romanelli, Fabio; Panza, Giuliano F.; Ashish, Mr; Mir, Ramees R.

2014-05-01

The development of effective mitigation strategies requires scientifically consistent estimates of seismic ground motion; recent analysis, however, showed that the performances of the classical probabilistic approach to seismic hazard assessment (PSHA) are very unsatisfactory in anticipating ground shaking from future large earthquakes. Moreover, due to their basic heuristic limitations, the standard PSHA estimates are by far unsuitable when dealing with the protection of critical structures (e.g. nuclear power plants) and cultural heritage, where it is necessary to consider extremely long time intervals. Nonetheless, the persistence in resorting to PSHA is often explained by the need to deal with uncertainties related with ground shaking and earthquakes recurrence. We show that current computational resources and physical knowledge of the seismic waves generation and propagation processes, along with the improving quantity and quality of geophysical data, allow nowadays for viable numerical and analytical alternatives to the use of PSHA. The advanced approach considered in this study, namely the NDSHA (neo-deterministic seismic hazard assessment), is based on the physically sound definition of a wide set of credible scenario events and accounts for uncertainties and earthquakes recurrence in a substantially different way. The expected ground shaking due to a wide set of potential earthquakes is defined by means of full waveforms modelling, based on the possibility to efficiently compute synthetic seismograms in complex laterally heterogeneous anelastic media. In this way a set of scenarios of ground motion can be defined, either at national and local scale, the latter considering the 2D and 3D heterogeneities of the medium travelled by the seismic waves. The efficiency of the NDSHA computational codes allows for the fast generation of hazard maps at the regional scale even on a modern laptop computer. At the scenario scale, quick parametric studies can be easily

The Puerto Rico Component of the National Tsunami Hazard and Mitigation Program Pr-Nthmp

NASA Astrophysics Data System (ADS)

Huerfano Moreno, V. A.; Hincapie-Cardenas, C. M.

2014-12-01

Tsunami hazard assessment, detection, warning, education and outreach efforts are intended to reduce losses to life and property. The Puerto Rico Seismic Network (PRSN) is participating in an effort with local and federal agencies, to developing tsunami hazard risk reduction strategies under the National Tsunami Hazards and Mitigation Program (NTHMP). This grant supports the TsunamiReady program which is the base of the tsunami preparedness and mitigation in PR. The Caribbean region has a documented history of damaging tsunamis that have affected coastal areas. The seismic water waves originating in the prominent fault systems around PR are considered to be a near-field hazard for Puerto Rico and the Virgin islands (PR/VI) because they can reach coastal areas within a few minutes after the earthquake. Sources for local, regional and tele tsunamis have been identified and modeled and tsunami evacuation maps were prepared for PR. These maps were generated in three phases: First, hypothetical tsunami scenarios on the basis of the parameters of potential underwater earthquakes were developed. Secondly, each of these scenarios was simulated. The third step was to determine the worst case scenario (MOM). The run-ups were drawn on GIS referenced maps and aerial photographs. These products are being used by emergency managers to educate the public and develop mitigation strategies. Online maps and related evacuation products are available to the public via the PR-TDST (PR Tsunami Decision Support Tool). Currently all the 44 coastal municipalities were recognized as TsunamiReady by the US NWS. The main goal of the program is to declare Puerto Rico as TsunamiReady, including two cities that are not coastal but could be affected by tsunamis. Based on these evacuation maps, tsunami signs were installed, vulnerability profiles were created, communication systems to receive and disseminate tsunami messages were installed in each TWFP, and tsunami response plans were approved

St. Louis area earthquake hazards mapping project; seismic and liquefaction hazard maps

USGS Publications Warehouse

Cramer, Chris H.; Bauer, Robert A.; Chung, Jae-won; Rogers, David; Pierce, Larry; Voigt, Vicki; Mitchell, Brad; Gaunt, David; Williams, Robert; Hoffman, David; Hempen, Gregory L.; Steckel, Phyllis; Boyd, Oliver; Watkins, Connor M.; Tucker, Kathleen; McCallister, Natasha

2016-01-01

We present probabilistic and deterministic seismic and liquefaction hazard maps for the densely populated St. Louis metropolitan area that account for the expected effects of surficial geology on earthquake ground shaking. Hazard calculations were based on a map grid of 0.005°, or about every 500 m, and are thus higher in resolution than any earlier studies. To estimate ground motions at the surface of the model (e.g., site amplification), we used a new detailed near‐surface shear‐wave velocity model in a 1D equivalent‐linear response analysis. When compared with the 2014 U.S. Geological Survey (USGS) National Seismic Hazard Model, which uses a uniform firm‐rock‐site condition, the new probabilistic seismic‐hazard estimates document much more variability. Hazard levels for upland sites (consisting of bedrock and weathered bedrock overlain by loess‐covered till and drift deposits), show up to twice the ground‐motion values for peak ground acceleration (PGA), and similar ground‐motion values for 1.0 s spectral acceleration (SA). Probabilistic ground‐motion levels for lowland alluvial floodplain sites (generally the 20–40‐m‐thick modern Mississippi and Missouri River floodplain deposits overlying bedrock) exhibit up to twice the ground‐motion levels for PGA, and up to three times the ground‐motion levels for 1.0 s SA. Liquefaction probability curves were developed from available standard penetration test data assuming typical lowland and upland water table levels. A simplified liquefaction hazard map was created from the 5%‐in‐50‐year probabilistic ground‐shaking model. The liquefaction hazard ranges from low (60% of area expected to liquefy) in the lowlands. Because many transportation routes, power and gas transmission lines, and population centers exist in or on the highly susceptible lowland alluvium, these areas in the St. Louis region are at significant potential risk from seismically induced liquefaction and associated

New Multi-HAzard and MulTi-RIsk Assessment MethodS for Europe (MATRIX): A research program towards mitigating multiple hazards and risks in Europe

NASA Astrophysics Data System (ADS)

Fleming, K. M.; Zschau, J.; Gasparini, P.; Modaressi, H.; Matrix Consortium

2011-12-01

Scientists, engineers, civil protection and disaster managers typically treat natural hazards and risks individually. This leads to the situation where the frequent causal relationships between the different hazards and risks, e.g., earthquakes and volcanos, or floods and landslides, are ignored. Such an oversight may potentially lead to inefficient mitigation planning. As part of their efforts to confront this issue, the European Union, under its FP7 program, is supporting the New Multi-HAzard and MulTi-RIsK Assessment MethodS for Europe or MATRIX project. The focus of MATRIX is on natural hazards, in particular earthquakes, landslides, volcanos, wild fires, storms and fluvial and coastal flooding. MATRIX will endeavour to develop methods and tools to tackle multi-type natural hazards and risks within a common framework, focusing on methodologies that are suited to the European context. The work will involve an assessment of current single-type hazard and risk assessment methodologies, including a comparison and quantification of uncertainties and harmonization of single-type methods, examining the consequence of cascade effects within a multi-hazard environment, time-dependent vulnerability, decision making and support for multi-hazard mitigation and adaption, and a series of test cases. Three test sites are being used to assess the methods developed within the project (Naples, Cologne, and the French West Indies), as well as a "virtual city" based on a comprehensive IT platform that will allow scenarios not represented by the test cases to be examined. In addition, a comprehensive dissemination program that will involve national platforms for disaster management, as well as various outreach activities, will be undertaken. The MATRIX consortium consists of ten research institutions (nine European and one Canadian), an end-user (i.e., one of the European national platforms for disaster reduction) and a partner from industry.

Earthquake scenarios based on lessons from the past

NASA Astrophysics Data System (ADS)

Solakov, Dimcho; Simeonova, Stella; Aleksandrova, Irena; Popova, Iliana

2010-05-01

Earthquakes are the most deadly of the natural disasters affecting the human environment; indeed catastrophic earthquakes have marked the whole human history. Global seismic hazard and vulnerability to earthquakes are increasing steadily as urbanization and development occupy more areas that are 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 implementation of the earthquake scenarios into the policies for seismic risk reduction will allow focusing on the prevention of earthquake effects rather than on intervention following the disasters. The territory of Bulgaria (situated in the eastern part of the Balkan Peninsula) represents a typical example of high seismic risk area. Over the centuries, Bulgaria has experienced strong earthquakes. At the beginning of the 20-the century (from 1901 to 1928) five earthquakes with magnitude larger than or equal to MS=7.0 occurred in Bulgaria. However, no such large earthquakes occurred in Bulgaria since 1928, which may induce non-professionals to underestimate the earthquake risk. The 1986 earthquake of magnitude MS=5.7 occurred in the central northern Bulgaria (near the town of Strazhitsa) is the strongest quake after 1928. Moreover, the seismicity of the neighboring countries, like Greece, Turkey, former Yugoslavia and Romania (especially Vrancea-Romania intermediate earthquakes), influences the seismic hazard in Bulgaria. In the present study deterministic scenarios (expressed in seismic intensity) for two Bulgarian cities (Rouse and Plovdiv) are presented. The work on

Earthquake and Tsunami History and Hazards of Eastern Indonesia

NASA Astrophysics Data System (ADS)

Major, J. R.; Robinson, J. S.; Harris, R. A.

2008-12-01

Western Indonesia (i.e. Java and Sumatra) has received much attention by geoscientists, especially in recent years due to events such as the Sumatra-Andaman event of 2004. However, the seismic history of eastern Indonesia is not widely known, notwithstanding the high rate of seismic activity in the area and high convergence rates. Not only do geologic hazards (i.e. strong earthquakes, tsunami, and explosive volcanoes) comparable to those in western part of the country exist, but population has increased nearly 10 fold in the last century. Our historical research of earthquakes and tsunami in eastern Indonesia based primarily on records of Dutch Colonists has uncovered a violent history of earthquakes and tsunami from 1608 to 1877. During this time eastern Indonesia experienced over 30 significant earthquakes and 35 tsunamis. Most of these events are much larger than any recorded in the last century. Due to this marked quiescence over the past century, and recent events in the Sunda arc over the past several years, we have initiated a new investigation of the region that integrates these historic events, field investigations, and, in the future, tsunami modeling. A more complete and comprehensive seismic history of eastern Indonesia is necessary for effective risk assessment. This information, along with renewed efforts by scientists and government will be crucial for disaster mitigation and to save lives.

The Effects of the Passage of Time from the 2011 Tohoku Earthquake on the Public’s Anxiety about a Variety of Hazards

PubMed Central

Nakayachi, Kazuya; Nagaya, Kazuhisa

2016-01-01

This research investigated whether the Japanese people’s anxiety about a variety of hazards, including earthquakes and nuclear accidents, has changed over time since the Tohoku Earthquake in 2011. Data from three nationwide surveys conducted in 2008, 2012, and 2015 were compared to see the change in societal levels of anxiety toward 51 types of hazards. The same two-phase stratified random sampling method was used to create the list of participants in each survey. The results showed that anxiety about earthquakes and nuclear accidents had increased for a time after the Tohoku Earthquake, and then decreased after a four-year time frame with no severe earthquakes and nuclear accidents. It was also revealed that the anxiety level for some hazards other than earthquakes and nuclear accidents had decreased at ten months after the Earthquake, and then remained unchanged after the four years. Therefore, ironically, a major disaster might decrease the public anxiety in general at least for several years. PMID:27589780

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

NASA Astrophysics Data System (ADS)

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

Seismic hazard assessment based on the Unified Scaling Law for Earthquakes: the Greater Caucasus

NASA Astrophysics Data System (ADS)

Nekrasova, A.; Kossobokov, V. G.

2015-12-01

Losses from natural disasters continue to increase mainly due to poor understanding by majority of scientific community, decision makers and public, the three components of Risk, i.e., Hazard, Exposure, and Vulnerability. Contemporary Science is responsible for not coping with challenging changes of Exposures and their Vulnerability inflicted by growing population, its concentration, etc., which result in a steady increase of Losses from Natural Hazards. Scientists owe to Society for lack of knowledge, education, and communication. In fact, Contemporary Science can do a better job in disclosing Natural Hazards, assessing Risks, and delivering such knowledge in advance catastrophic events. We continue applying the general concept of seismic risk analysis in a number of seismic regions worldwide by constructing regional seismic hazard maps based on the Unified Scaling Law for Earthquakes (USLE), i.e. log N(M,L) = A - B•(M-6) + C•log L, where N(M,L) is the expected annual number of earthquakes of a certain magnitude M within an seismically prone area of linear dimension L. The parameters A, B, and C of USLE are used to estimate, first, the expected maximum magnitude in a time interval at a seismically prone cell of a uniform grid that cover the region of interest, and then the corresponding expected ground shaking parameters including macro-seismic intensity. After a rigorous testing against the available seismic evidences in the past (e.g., the historically reported macro-seismic intensity), such a seismic hazard map is used to generate maps of specific earthquake risks (e.g., those based on the density of exposed population). The methodology of seismic hazard and risks assessment based on USLE is illustrated by application to the seismic region of Greater Caucasus.

Seismic hazard, risk, and design for South America

USGS Publications Warehouse

Petersen, Mark D.; Harmsen, Stephen; Jaiswal, Kishor; Rukstales, Kenneth S.; Luco, Nicolas; Haller, Kathleen; Mueller, Charles; Shumway, Allison

2018-01-01

We calculate seismic hazard, risk, and design criteria across South America using the latest data, models, and methods to support public officials, scientists, and engineers in earthquake risk mitigation efforts. Updated continental scale seismic hazard models are based on a new seismicity catalog, seismicity rate models, evaluation of earthquake sizes, fault geometry and rate parameters, and ground‐motion models. Resulting probabilistic seismic hazard maps show peak ground acceleration, modified Mercalli intensity, and spectral accelerations at 0.2 and 1 s periods for 2%, 10%, and 50% probabilities of exceedance in 50 yrs. Ground shaking soil amplification at each site is calculated by considering uniform soil that is applied in modern building codes or by applying site‐specific factors based on VS30">VS30 shear‐wave velocities determined through a simple topographic proxy technique. We use these hazard models in conjunction with the Prompt Assessment of Global Earthquakes for Response (PAGER) model to calculate economic and casualty risk. Risk is computed by incorporating the new hazard values amplified by soil, PAGER fragility/vulnerability equations, and LandScan 2012 estimates of population exposure. We also calculate building design values using the guidelines established in the building code provisions. Resulting hazard and associated risk is high along the northern and western coasts of South America, reaching damaging levels of ground shaking in Chile, western Argentina, western Bolivia, Peru, Ecuador, Colombia, Venezuela, and in localized areas distributed across the rest of the continent where historical earthquakes have occurred. Constructing buildings and other structures to account for strong shaking in these regions of high hazard and risk should mitigate losses and reduce casualties from effects of future earthquake strong ground shaking. National models should be developed by scientists and engineers in each country using the best

Earthquake and Volcanic Hazard Mitigation and Capacity Building in Sub-Saharan Africa

NASA Astrophysics Data System (ADS)

Ayele, A.

2012-04-01

The East African Rift System (EARS) is a classic example of active continental rifting, and a natural laboratory setting to study initiation and early stage evolution of continental rifts. The EARS is at different stages of development that varies from relatively matured rift (16 mm/yr) in the Afar to a weakly extended Okavango Delta in the south with predicted opening velocity < 3 mm/yr. Recent studies in the region helped researchers to highlight the length and timescales of magmatism and faulting, the partitioning of strain between faulting and magmatism, and their implications for the development of along-axis segmentation. Although the human resource and instrument coverage is sparse in the continent, our understanding of rift processes and deep structure has improved in the last decade after the advent of space geodesy and broadband seismology. The recent major earthquakes, volcanic eruptions and mega dike intrusions that occurred along the EARS attracted several earth scientist teams across the globe. However, most African countries traversed by the rift do not have the full capacity to monitor and mitigate earthquake and volcanic hazards. Few monitoring facilities exist in some countries, and the data acquisition is rarely available in real-time for mitigation purpose. Many sub-Saharan Africa governments are currently focused on achieving the millennium development goals with massive infrastructure development scheme and urbanization while impending natural hazards of such nature are severely overlooked. Collaborations with overseas researchers and other joint efforts by the international community are opportunities to be used by African institutions to best utilize limited resources and to mitigate earthquake and volcano hazards.

Earthquake and volcano hazard notices: An economic evaluation of changes in risk perceptions

USGS Publications Warehouse

Bernknopf, R.L.; Brookshire, D.S.; Thayer, M.A.

1990-01-01

Earthquake and volcano hazard notices were issued for the Mammoth Lakes, California area by the U.S. Geological Survey under the authority granted by the Disaster Relief Act of 1974. The effects on investment, recretion visitation, and risk perceptionsare explored. The hazard notices did not affect recreation visitation, although investment was affected. A perceived loss in the market value of homes was documented. Risk perceptions were altered for property owners. Communication of the probability of an event over time would enhance hazard notices as a policy instrument and would mitigate unnecessary market perturbations. ?? 1990.

Earthquake Education in Prime Time

NASA Astrophysics Data System (ADS)

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

New Seafloor Map of the Puerto Rico Trench Helps Assess Earthquake and Tsunami Hazards

NASA Astrophysics Data System (ADS)

ten Brink, Uri; Danforth, William; Polloni, Christopher; Andrews, Brian; Llanes, Pilar; Smith, Shepard; Parker, Eugene; Uozumi, Toshihiko

2004-09-01

The Puerto Rico Trench, the deepest part of the Atlantic Ocean, is located where the North American (NOAM) plate is subducting under the Caribbean plate (Figure 1). The trench region may pose significant seismic and tsunami hazards to Puerto Rico and the U.S. Virgin Islands, where 4 million U.S. citizens reside. Widespread damage in Puerto Rico and Hispaniola from an earthquake in 1787 was estimated to be the result of a magnitude 8 earthquake north of the islands. A tsunami killed 40 people in NW Puerto Rico following a magnitude 7.3 earthquake in 1918. Large landslide escarpments have been mapped on the seafloor north of Puerto Rico, although their ages are unknown. The Puerto Rico Trench is atypical of oceanic trenches. Subduction is highly oblique (10°-20°) to the trench axis with a large component of left-lateral strike-slip motion. Similar convergence geometry is observed at the Challenger Deep in the Mariana Trench, the deepest point on Earth. In addition to its extremely deep seafloor, the Puerto Rico Trench is also characterized by the most negative free-air gravity anomaly on Earth, -380 mGal, located 50 km south of the trench, where water depth is 7950 m (Figure 2). A tilted carbonate platform provides evidence for extreme vertical tectonism in the region. This platform was horizontally deposited over Cretaceous to Paleocene arc rocks starting in the Late Oligocene. Then, at 3.5 Ma, the carbonate platform was tilted by 4° toward the trench over a time period of less than 40 kyr, such that its northern edge is at a depth of 4000 m and its reconstructed elevation on land in Puerto Rico is at +1300 m (Figures 1 and 2).

Discrepancy between earthquake rates implied by historic earthquakes and a consensus geologic source model for California

USGS Publications Warehouse

Petersen, M.D.; Cramer, C.H.; Reichle, M.S.; Frankel, A.D.; Hanks, T.C.

2000-01-01

We examine the difference between expected earthquake rates inferred from the historical earthquake catalog and the geologic data that was used to develop the consensus seismic source characterization for the state of California [California Department of Conservation, Division of Mines and Geology (CDMG) and U.S. Geological Survey (USGS) Petersen et al., 1996; Frankel et al., 1996]. On average the historic earthquake catalog and the seismic source model both indicate about one M 6 or greater earthquake per year in the state of California. However, the overall earthquake rates of earthquakes with magnitudes (M) between 6 and 7 in this seismic source model are higher, by at least a factor of 2, than the mean historic earthquake rates for both southern and northern California. The earthquake rate discrepancy results from a seismic source model that includes earthquakes with characteristic (maximum) magnitudes that are primarily between M 6.4 and 7.1. Many of these faults are interpreted to accommodate high strain rates from geologic and geodetic data but have not ruptured in large earthquakes during historic time. Our sensitivity study indicates that the rate differences between magnitudes 6 and 7 can be reduced by adjusting the magnitude-frequency distribution of the source model to reflect more characteristic behavior, by decreasing the moment rate available for seismogenic slip along faults, by increasing the maximum magnitude of the earthquake on a fault, or by decreasing the maximum magnitude of the background seismicity. However, no single parameter can be adjusted, consistent with scientific consensus, to eliminate the earthquake rate discrepancy. Applying a combination of these parametric adjustments yields an alternative earthquake source model that is more compatible with the historic data. The 475-year return period hazard for peak ground and 1-sec spectral acceleration resulting from this alternative source model differs from the hazard resulting from the

Assessment of tsunami hazard to the U.S. Atlantic margin

USGS Publications Warehouse

ten Brink, Uri S.; Chaytor, Jason; Geist, Eric L.; Brothers, Daniel S.; Andrews, Brian D.

2014-01-01

Tsunamis caused by atmospheric disturbances and by coastal earthquakes may be more frequent than those generated by landslides, but their amplitudes are probably smaller. Among the possible far-field earthquake sources, only earthquakes located within the Gulf of Cadiz or west of the Tore-Madeira Rise are likely to affect the U.S. coast. It is questionable whether earthquakes on the Puerto Rico Trench are capable of producing a large enough tsunami that will affect the U.S. Atlantic coast. More information is needed to evaluate the seismic potential of the northern Cuba fold-and-thrust belt. The hazard from a volcano flank collapse in the Canary Islands is likely smaller than originally stated, and there is not enough information to evaluate the magnitude and frequency of flank collapse from the Azores Islands. Both deterministic and probabilistic methods to evaluate the tsunami hazard from the margin are available for application to the Atlantic margin, but their implementation requires more information than is currently available.

Population and business exposure to twenty scenario earthquakes in the State of Washington

USGS Publications Warehouse

Wood, Nathan; Ratliff, Jamie

2011-01-01

This report documents the results of an initial analysis of population and business exposure to scenario earthquakes in Washington. This analysis was conducted to support the U.S. Geological Survey (USGS) Pacific Northwest Multi-Hazards Demonstration Project (MHDP) and an ongoing collaboration between the State of Washington Emergency Management Division (WEMD) and the USGS on earthquake hazards and vulnerability topics. This report was developed to help WEMD meet internal planning needs. A subsequent report will provide analysis to the community level. The objective of this project was to use scenario ground-motion hazard maps to estimate population and business exposure to twenty Washington earthquakes. In consultation with the USGS Earthquake Hazards Program and the Washington Division of Geology and Natural Resources, the twenty scenario earthquakes were selected by WEMD (fig. 1). Hazard maps were then produced by the USGS and placed in the USGS ShakeMap archive.

A seismic hazard overview of the Mitidja Basin (Northern Algeria)

NASA Astrophysics Data System (ADS)

Fontiela, J. F.; Borges, J.; Ouyed, M.; Bezzeghoud, M.; Idres, M.; Caldeira, B.; Boughacha, M. S.; Carvalho, J.; Samai, S.; Aissa, S.; Benfadda, A.; Chimouni, R.; Yalaoui, R.; Dias, R.

2017-12-01

The Mitidja Basin (MB) is located in N Algeria and it is filled by quaternary sediments with a length of 100 km on the EW direction and around 20 km width. The S and N limites comprise the Boumerdes-Larbaa-Blida, and the Thenia-Sahel active fault system, respectively. Both fault systems are of the reverse type with opposed dips and accommodate a general slip rate of ˜4 mm/year. In the basin occurred earthquakes that caused severe damage and losses such as the ones of Algiers (1365, Io=X; 1716, Io=X) and the Bourmedes earthquake (Mw 6.9; May 2003) that affected the area of Zemmouri and caused 2.271 deaths. The event was caused by the reactivation of the MB boundary faults. The earthquake generated a max uplift of 0.8m along the coast and a horizontal max. slip of 0.24m.Recent studies show that the Boumerdes earthquake overloaded the adjacent faults system with a stress increase between 0.4 and 1.5 bar. The stress change recommends a detailed study of mentioned faults system due to the increase of the seismic hazard. The high seismogenic potential of the fault system bordering the MB, increases the vulnerability of densely populated areas of Algiers and the amplification effect caused by the basin are the motivation of this project that will focus on the evaluation of the seismic hazard of the region. To achieve seismic hazard assessment on the MB, through realistic predictions of strong ground motion, caused by moderate and large earthquakes, it is important 1) develop a detailed 3D velocity/structure model of the MB that includes geological constraints, seismic reflection data acquired on wells, refraction velocities and seismic noise data, and determination of the attenuation laws based on instrumental records; 2) evaluate the seismic potential and parameters of the main active faults of the MB; 3) develop numerical methods (deterministic and stochastic) to simulate strong ground motions produced by extended seismic sources. To acquire seismic noise were used

St. Louis Area Earthquake Hazards Mapping Project - December 2008-June 2009 Progress Report

USGS Publications Warehouse

Williams, R.A.; Bauer, R.A.; Boyd, O.S.; Chung, J.; Cramer, C.H.; Gaunt, D.A.; Hempen, G.L.; Hoffman, D.; McCallister, N.S.; Prewett, J.L.; Rogers, J.D.; Steckel, P.J.; Watkins, C.M.

2009-01-01

This report summarizes the mission, the project background, the participants, and the progress of the St. Louis Area Earthquake Hazards Mapping Project (SLAEHMP) for the period from December 2008 through June 2009. During this period, the SLAEHMP held five conference calls and two face-to-face meetings in St. Louis, participated in several earthquake awareness public meetings, held one outreach field trip for the business and government community, collected and compiled new borehole and digital elevation data from partners, and published a project summary.

A recent Mw 4.3 earthquake proving activity of a shallow strike-slip fault in the northern part of the Western Desert, Egypt

NASA Astrophysics Data System (ADS)

Ezzelarab, Mohamed; Ebraheem, Mohamed O.; Zahradník, Jiří

2018-03-01

The Mw 4.3 earthquake of September 2015 is the first felt earthquake since 1900 A.D in the northern part of the Western Desert, Egypt, south of the El-Alamein City. The available waveform data observed at epicentral distances 52-391 km was collected and carefully evaluated. Nine broad-band stations were selected to invert full waveforms for the centroid position (horizontal and vertical) and for the focal mechanism solution. The first-arrival travel times, polarities and low-frequency full waveforms (0.03-0.08 Hz) are consistently explained in this paper as caused by a shallow source of the strike-slip mechanism. This finding indicates causal relation of this earthquake to the W-E trending South El-Alamein fault, which developed in Late Cretaceous as dextral strike slip fault. Recent activity of this fault, proven by the studied rare earthquake, is of fundamental importance for future seismic hazard evaluations, underlined by proximity (∼65 km) of the source zone to the first nuclear power plant planned site in Egypt. Safe exploration and possible future exploitation of hydrocarbon reserves, reported around El-Alamein fault in the last decade, cannot be made without considering the seismic potential of this fault.

Performance of USGS one-year earthquake hazard map for natural and induced seismicity in the central and eastern United States

NASA Astrophysics Data System (ADS)

Brooks, E. M.; Stein, S.; Spencer, B. D.; Salditch, L.; Petersen, M. D.; McNamara, D. E.

2017-12-01

Seismicity in the central United States has dramatically increased since 2008 due to the injection of wastewater produced by oil and gas extraction. In response, the USGS created a one-year probabilistic hazard model and map for 2016 to describe the increased hazard posed to the central and eastern United States. Using the intensity of shaking reported to the "Did You Feel It?" system during 2016, we assess the performance of this model. Assessing the performance of earthquake hazard maps for natural and induced seismicity is conceptually similar but has practical differences. Maps that have return periods of hundreds or thousands of years— as commonly used for natural seismicity— can be assessed using historical intensity data that also span hundreds or thousands of years. Several different features stand out when assessing the USGS 2016 seismic hazard model for the central and eastern United States from induced and natural earthquakes. First, the model can be assessed as a forecast in one year, because event rates are sufficiently high to permit evaluation with one year of data. Second, because these models are projections from the previous year thus implicitly assuming that fluid injection rates remain the same, misfit may reflect changes in human activity. Our results suggest that the model was very successful by the metric implicit in probabilistic hazard seismic assessment: namely, that the fraction of sites at which the maximum shaking exceeded the mapped value is comparable to that expected. The model also did well by a misfit metric that compares the spatial patterns of predicted and maximum observed shaking. This was true for both the central and eastern United States as a whole, and for the region within it with the highest amount of seismicity, Oklahoma and its surrounding area. The model performed least well in northern Texas, over-stating hazard, presumably because lower oil and gas prices and regulatory action reduced the water injection volume

Tsunami Hazard in the Algerian Coastline

NASA Astrophysics Data System (ADS)

Amir, L. A.

2008-05-01

The Algerian coastline is located at the border between the African and the Eurasian tectonic plates. The collision between these two plates is approximately 4 to 7 mm/yr. The Alps and the tellian Atlas result from this convergence. Historical and present day data show the occurrence of earthquakes with magnitude up to 7 degrees on Richter scale in the northern part of the country. Cities were destroyed and the number of victims reached millions of people. Recently, small seismic waves generated by a destructive earthquake (Epicenter: 36.90N, 3.71E; Mw=6.8; Algeria, 2003, NEIC) were recorded in the French and Spanish coasts. This event raised again the issue of tsunami hazard in western Mediterranean region. For the Algerian study case, the assessment of seismic and tsunami hazard is a matter of great interest because of fast urban development of cities like Algiers. This study aims to provide scientific arguments to help in the elaboration of the Mediterranean tsunami alert program. This is a real complex issue because (1) the western part of the sea is narrow, (2) constructions on the Algerian coastline do not respect safety standards and (3) the seismic hazard is important. The present work is based on a numerical modeling approach. Firstly, a database is created to gather and list information related to seismology, tectonic, abnormal sea level's variations recorded/observed, submarine and coastal topographic data for the western part of the Mediterranean margin. This database helped to propose series of scenario that could trigger tsunami in the Mediterranean sea. Seismic moment, rake and focal depth are the major parameters that constrain the modeling input seismic data. Then, the undersea earthquakes modeling and the seabed deformations are computed with a program adapted from the rngchn code based on Okada's analytic equations. The last task of this work consisted to calculate the initial water surface displacement and simulate the triggered tsunami

Errors in Seismic Hazard Assessment are Creating Huge Human Losses

NASA Astrophysics Data System (ADS)

Bela, J.

2015-12-01

The current practice of representing earthquake hazards to the public based upon their perceived likelihood or probability of occurrence is proven now by the global record of actual earthquakes to be not only erroneous and unreliable, but also too deadly! Earthquake occurrence is sporadic and therefore assumptions of earthquake frequency and return-period are both not only misleading, but also categorically false. More than 700,000 people have now lost their lives (2000-2011), wherein 11 of the World's Deadliest Earthquakes have occurred in locations where probability-based seismic hazard assessments had predicted only low seismic low hazard. Unless seismic hazard assessment and the setting of minimum earthquake design safety standards for buildings and bridges are based on a more realistic deterministic recognition of "what can happen" rather than on what mathematical models suggest is "most likely to happen" such future huge human losses can only be expected to continue! The actual earthquake events that did occur were at or near the maximum potential-size event that either already had occurred in the past; or were geologically known to be possible. Haiti's M7 earthquake, 2010 (with > 222,000 fatalities) meant the dead could not even be buried with dignity. Japan's catastrophic Tohoku earthquake, 2011; a M9 Megathrust earthquake, unleashed a tsunami that not only obliterated coastal communities along the northern Japanese coast, but also claimed > 20,000 lives. This tsunami flooded nuclear reactors at Fukushima, causing 4 explosions and 3 reactors to melt down. But while this history of huge human losses due to erroneous and misleading seismic hazard estimates, despite its wrenching pain, cannot be unlived; if faced with courage and a more realistic deterministic estimate of "what is possible", it need not be lived again. An objective testing of the results of global probability based seismic hazard maps against real occurrences has never been done by the

The Carlisle earthquake of December 26, 1979, in northern England

USGS Publications Warehouse

Neilson, G.

1980-01-01

At 3:57 a.m on the morning after Christmas Day 1979, a large area of northern England and southern Scotland was shaken by an earthquake. In the mesoseismal area, a few miles north of Carlisle, chimneys toppled into the streets or fell through roofs, and people ran in panic into the open. Over a much wider area, including the densely populated industrial area of central Scotland, people were awakened, and ornaments and other small objects were disturbed. At distances over 120 miles from the epicenter, only a few people noted the tremor. Northern Ireland and the Isle of Man also expereienced the tremor but reportedly at no very great intensity. The distrubed area covered approximately 45,00 square miles. 

Seismic hazard maps for Haiti

USGS Publications Warehouse

Frankel, Arthur; Harmsen, Stephen; Mueller, Charles; Calais, Eric; Haase, Jennifer

2011-01-01

We have produced probabilistic seismic hazard maps of Haiti for peak ground acceleration and response spectral accelerations that include the hazard from the major crustal faults, subduction zones, and background earthquakes. The hazard from the Enriquillo-Plantain Garden, Septentrional, and Matheux-Neiba fault zones was estimated using fault slip rates determined from GPS measurements. The hazard from the subduction zones along the northern and southeastern coasts of Hispaniola was calculated from slip rates derived from GPS data and the overall plate motion. Hazard maps were made for a firm-rock site condition and for a grid of shallow shear-wave velocities estimated from topographic slope. The maps show substantial hazard throughout Haiti, with the highest hazard in Haiti along the Enriquillo-Plantain Garden and Septentrional fault zones. The Matheux-Neiba Fault exhibits high hazard in the maps for 2% probability of exceedance in 50 years, although its slip rate is poorly constrained.

Reevaluation of the Seismicity and seismic hazards of Northeastern Libya

NASA Astrophysics Data System (ADS)

Ben Suleman, abdunnur; Aousetta, Fawzi

2014-05-01

Libya, located at the northern margin of the African continent, underwent many episodes of orogenic activities. These episodes of orogenic activities affected and shaped the geological setting of the country. This study represents a detailed investigation that aims to focus on the seismicity and its implications on earthquake hazards of Northeastern Libya. At the end of year 2005 the Libyan National Seismological Network starts functioning with 15 stations. The Seismicity of the area under investigation was reevaluated using data recorded by the recently established network. The Al-Maraj earthquake occurred in May 22nd 2005was analyzed. This earthquake was located in a known seismically active area. This area was the sight of the well known 1963 earthquake that kills over 200 people. Earthquakes were plotted and resulting maps were interpreted and discussed. The level of seismic activity is higher in some areas, such as the city of Al-Maraj. The offshore areas north of Al-Maraj seem to have higher seismic activity. It is highly recommended that the recent earthquake activity is considered in the seismic hazard assessments for the northeastern part of Libya.

Java Programs for Using Newmark's Method and Simplified Decoupled Analysis to Model Slope Performance During Earthquakes

USGS Publications Warehouse

Jibson, Randall W.; Jibson, Matthew W.

2003-01-01

Landslides typically cause a large proportion of earthquake damage, and the ability to predict slope performance during earthquakes is important for many types of seismic-hazard analysis and for the design of engineered slopes. Newmark's method for modeling a landslide as a rigid-plastic block sliding on an inclined plane provides a useful method for predicting approximate landslide displacements. Newmark's method estimates the displacement of a potential landslide block as it is subjected to earthquake shaking from a specific strong-motion record (earthquake acceleration-time history). A modification of Newmark's method, decoupled analysis, allows modeling landslides that are not assumed to be rigid blocks. This open-file report is available on CD-ROM and contains Java programs intended to facilitate performing both rigorous and simplified Newmark sliding-block analysis and a simplified model of decoupled analysis. For rigorous analysis, 2160 strong-motion records from 29 earthquakes are included along with a search interface for selecting records based on a wide variety of record properties. Utilities are available that allow users to add their own records to the program and use them for conducting Newmark analyses. Also included is a document containing detailed information about how to use Newmark's method to model dynamic slope performance. This program will run on any platform that supports the Java Runtime Environment (JRE) version 1.3, including Windows, Mac OSX, Linux, Solaris, etc. A minimum of 64 MB of available RAM is needed, and the fully installed program requires 400 MB of disk space.

Safe-Taipei a Program Project for Strong Motions, Active Faults, and Earthquakes in the Taipei Metropolitan Area

NASA Astrophysics Data System (ADS)

Wang, Jeen-Hwa

Strong collision between the Eurasian and Philippine Sea Plates causes high seismicity in the Taiwan region, which is often attacked by large earthquakes. Several cities, including three mega-cities, i.e., Taipei, Taichung, and Kaoshung, have been constructed on western Taiwan, where is lying on thick sediments. These cities, with a high-population density, are usually a regional center of culture, economics, and politics. Historically, larger-sized earthquakes, e.g. the 1935 Hsingchu—Taichung earthquake and the 1999 Chi—Chi earthquake, often caused serious damage on the cities. Hence, urban seismology must be one of the main subjects of Taiwan's seismological community. Since 2005, a program project, sponsored by Academia Sinica, has been launched to investigate seismological problems in the Taipei Metropolitan Area. This program project is performed during the 2005—2007 period. The core research subjects are: (1) the deployment of the Taipei Down-hole Seismic Array; (2) the properties of earthquakes and active faults in the area; (3) the seismogenic-zone structures, including the 3-D velocity and Q structures, of the area; (4) the characteristics of strong-motions and sites affects; and (5) strong-motion prediction. In addition to academic goals, the results obtained from the program project will be useful for seismic hazard mitigation not only for the area but also for others.

Scientists Engage South Carolina Community in Earthquake Education and Preparedness

NASA Astrophysics Data System (ADS)

Hall, C.; Beutel, E.; Jaume', S.; Levine, N.; Doyle, B.

2008-12-01

Scientists at the College of Charleston are working with the state of South Carolina's Emergency Management Division to increase awareness and understanding of earthquake hazards throughout South Carolina. As part of this mission, the SCEEP (South Carolina Earthquake Education and Preparedness) program was formed at the College of Charleston to promote earthquake research, outreach, and education in the state of South Carolina. Working with local, regional, state and federal offices, SCEEP has developed education programs for everyone from professional hazard management teams to formal and informal educators. SCEEP also works with the media to ensure accurate reporting of earthquake and other hazard information and to increase the public's understanding of earthquake science and earthquake seismology. As part of this program, we have developed a series of activities that can be checked out by educators for use in their classrooms and in informal education venues. These activities are designed to provide educators with the information and tools they lack to adequately, informatively, and enjoyably teach about earthquake and earth science. The toolkits contain seven activities meeting a variety of National Education Standards, not only in Science, but also in Geography, Math, Social Studies, Arts Education, History and Language Arts - providing a truly multidisciplinary toolkit for educators. The activities provide information on earthquake myths, seismic waves, elastic rebound, vectors, liquefaction, location of an epicenter, and then finally South Carolina earthquakes. The activities are engaging and inquiry based, implementing proven effective strategies for peaking learners' interest in scientific phenomena. All materials are provided within the toolkit and so it is truly check and go. While the SCEEP team has provided instructions and grade level suggestions for implementing the activity in an educational setting, the educator has full reign on what to showcase

Were they all giants? Perspectives on late Holocene plate-boundary earthquakes at the northern end of the Cascadia subduction zone

NASA Astrophysics Data System (ADS)

Hutchinson, Ian; Clague, John

2017-08-01

The relative magnitude of plate-boundary earthquakes at the northern end of the Cascadia subduction zone was assessed from the temporal concordance between the ages of coseismically buried late Holocene soils in southwest Washington, their counterparts in central and southern Cascadia, offshore turbidites, and paleoseismic deposits on the west coast of Vancouver Island. Only three of the seven buried soils in southwest Washington that can be reliably traced as buried soils or paleotsunami deposits in the coastal lowlands of south-central and southern Cascadia have well-dated counterparts in northern Cascadia. The three wide-ranging events date from Cascadia earthquakes Y (∼250 cal BP), U (∼1260 cal BP), and N (∼2520 cal BP). All three likely ruptured the entire plate margin, and therefore potentially qualify as ;giants; (Mw ≥ 9). Deposits that may derive from tsunamis generated by earthquakes S (∼1570 cal BP), L (∼2870 cal BP) and J (∼3360 cal BP) can also be found in northern Cascadia, but the ages of these deposits are not yet well-enough constrained to determine whether they are coeval with their southern counterparts. Earthquake W (∼850 cal BP), appears to be present in the northern Cascadia paleoseismic record, but yields considerably older ages than in central Cascadia, and may be missing from southernmost Cascadia. The onshore record of an offshore turbidite (T2) displays a similar spatio-temporal pattern to that of earthquake W.

Real-time Seismicity Evaluation as a Tool for the Earthquake and Tsunami Short-Term Hazard Assessment (Invited)

NASA Astrophysics Data System (ADS)

Papadopoulos, G. A.

2010-12-01

Seismic activity is a 3-D process varying in the space-time-magnitude domains. When in a target area the short-term activity deviates significantly from the usual (background) seismicity, then the modes of activity may include swarms, temporary quiescence, foreshock-mainshock-aftershock sequences, doublets and multiplets. This implies that making decision for civil protection purposes requires short-term seismic hazard assessment and evaluation. When a sizable earthquake takes place the critical question is about the nature of the event: mainshock or a foreshock which foreshadows the occurrence of a biger one? Also, the seismicity increase or decrease in a target area may signify either precursory changes or just transient seismicity variations (e.g. swarms) which do not conclude with a strong earthquake. Therefore, the real-time seismicity evaluation is the backbone of the short-term hazard assessment. The algorithm FORMA (Foreshock-Mainshock-Aftershock) is presented which detects and updates automatically and in near real-time significant variations of the seismicity according to the earthquake data flow from the monitoring center. The detection of seismicity variations is based on an expert system which for a given target area indicates the mode of seismicity from the variation of two parameters: the seismicity rate, r, and the b-value of the magnitude-frequency relation. Alert levels are produced according to the significance levels of the changes of r and b. The good performance of FORMA was verified retrospectively in several earthquake cases, e.g. for the L’ Aquila, Italy, 2009 earthquake sequence (Mmax 6.3) (Papadopoulos et al., 2010). Real-time testing was executed during January 2010 with the strong earthquake activity (Mmax 5.6) in the Corinth Rift, Central Greece. Evaluation outputs were publicly documented on a nearly daily basis with successful results. Evaluation of coastal and submarine earthquake activity is also of crucial importance for the

Post-earthquake building safety assessments for the Canterbury Earthquakes

USGS Publications Warehouse

Marshall, J.; Barnes, J.; Gould, N.; Jaiswal, K.; Lizundia, B.; Swanson, David A.; Turner, F.

2012-01-01

This paper explores the post-earthquake building assessment program that was utilized in Christchurch, New Zealand following the Canterbury Sequence of earthquakes beginning with the Magnitude (Mw.) 7.1 Darfield event in September 2010. The aftershocks or triggered events, two of which exceeded Mw 6.0, continued with events in February and June 2011 causing the greatest amount of damage. More than 70,000 building safety assessments were completed following the February event. The timeline and assessment procedures will be discussed including the use of rapid response teams, selection of indicator buildings to monitor damage following aftershocks, risk assessments for demolition of red-tagged buildings, the use of task forces to address management of the heavily damaged downtown area and the process of demolition. Through the post-event safety assessment program that occurred throughout the Canterbury Sequence of earthquakes, many important lessons can be learned that will benefit future response to natural hazards that have potential to damage structures.

Building a Communication, Education, an Outreach Program for the ShakeAlert National Earthquake Early Warning Program

NASA Astrophysics Data System (ADS)

DeGroot, R. M.; Strauss, J. A.; Given, D. D.; Cochran, E. S.; Burkett, E. R.; Long, K.

2016-12-01

Earthquake Early Warning (EEW) systems can provide as much as tens of seconds of warning to people and automated systems before strong shaking arrives. The United States Geological Survey (USGS) and its partners are developing an EEW system for the West Coast of the United States. To be an integral part of successful implementation, EEW engagement programs and materials must integrate with and leverage broader earthquake risk programs. New methods and products for dissemination must be multidisciplinary, cost effective, and consistent with existing hazards education efforts. Our presentation outlines how the USGS and its partners will approach this effort in the context of the EEW system through the work of a multistate and multiagency committee that participates in the design, implementation, and evaluation of a portfolio of programs and products. This committee, referred to as the ShakeAlert Joint Committee for Communication, Education, and Outreach (ShakeAlert CEO), is working to identify, develop, and cultivate partnerships with EEW stakeholders including Federal, State, academic partners, private companies, policy makers, and local organizations. Efforts include developing materials, methods for delivery, and reaching stakeholders with information on EEW, earthquake preparedness, and emergency protective actions. It is essential to develop standards to ensure information communicated via the EEW alerts is consistent across the public and private sector and achieving a common understanding of what actions users take when they receive an EEW warning. The USGS and the participating states and agencies acknowledge that the implementation of EEW is a collective effort requiring the participation of hundreds of stakeholders committed to ensuring public accessibility.

Earthquake induced liquefaction hazard, probability and risk assessment in the city of Kolkata, India: its historical perspective and deterministic scenario

NASA Astrophysics Data System (ADS)

Nath, Sankar Kumar; Srivastava, Nishtha; Ghatak, Chitralekha; Adhikari, Manik Das; Ghosh, Ambarish; Sinha Ray, S. P.

2018-01-01

Liquefaction-induced ground failure is one amongst the leading causes of infrastructure damage due to the impact of large earthquakes in unconsolidated, non-cohesive, water saturated alluvial terrains. The city of Kolkata is located on the potentially liquefiable alluvial fan deposits of Ganga-Bramhaputra-Meghna Delta system with subsurface litho-stratigraphic sequence comprising of varying percentages of clay, cohesionless silt, sand, and gravel interbedded with decomposed wood and peat. Additionally, the region has moderately shallow groundwater condition especially in the post-monsoon seasons. In view of burgeoning population, there had been unplanned expansion of settlements in the hazardous geological, geomorphological, and hydrological conditions exposing the city to severe liquefaction hazard. The 1897 Shillong and 1934 Bihar-Nepal earthquakes both of M w 8.1 reportedly induced Modified Mercalli Intensity of IV-V and VI-VII respectively in the city reportedly triggering widespread to sporadic liquefaction condition with surface manifestation of sand boils, lateral spreading, ground subsidence, etc., thus posing a strong case for liquefaction potential analysis in the terrain. With the motivation of assessing seismic hazard, vulnerability, and risk of the city of Kolkata through a consorted federal funding stipulated for all the metros and upstart urban centers in India located in BIS seismic zones III, IV, and V with population more than one million, an attempt has been made here to understand the liquefaction susceptibility condition of Kolkata under the impact of earthquake loading employing modern multivariate techniques and also to predict deterministic liquefaction scenario of the city in the event of a probabilistic seismic hazard condition with 10% probability of exceedance in 50 years and a return period of 475 years. We conducted in-depth geophysical and geotechnical investigations in the city encompassing 435 km2 area. The stochastically

Turning the rumor of May 11, 2011 earthquake prediction In Rome, Italy, into an information day on earthquake hazard

NASA Astrophysics Data System (ADS)

Amato, A.; Cultrera, G.; Margheriti, L.; Nostro, C.; Selvaggi, G.; INGVterremoti Team

2011-12-01

A devastating earthquake had been predicted for May 11, 2011 in Rome. This prediction was never released officially by anyone, but it grew up in the Internet and was amplified by media. It was erroneously ascribed to Raffaele Bendandi, an Italian self-taught natural scientist who studied planetary motions. Indeed, around May 11, 2011, a planetary alignment was really expected and this contributed to give credibility to the earthquake prediction among people. During the previous months, INGV was overwhelmed with requests for information about this supposed prediction by Roman inhabitants and tourists. Given the considerable mediatic impact of this expected earthquake, INGV decided to organize an Open Day in its headquarter in Rome for people who wanted to learn more about the Italian seismicity and the earthquake as natural phenomenon. The Open Day was preceded by a press conference two days before, in which we talked about this prediction, we presented the Open Day, and we had a scientific discussion with journalists about the earthquake prediction and more in general on the real problem of seismic risk in Italy. About 40 journalists from newspapers, local and national tv's, press agencies and web news attended the Press Conference and hundreds of articles appeared in the following days, advertising the 11 May Open Day. The INGV opened to the public all day long (9am - 9pm) with the following program: i) meetings with INGV researchers to discuss scientific issues; ii) visits to the seismic monitoring room, open 24h/7 all year; iii) guided tours through interactive exhibitions on earthquakes and Earth's deep structure; iv) lectures on general topics from the social impact of rumors to seismic risk reduction; v) 13 new videos on channel YouTube.com/INGVterremoti to explain the earthquake process and give updates on various aspects of seismic monitoring in Italy; vi) distribution of books and brochures. Surprisingly, more than 3000 visitors came to visit INGV

The Global Earthquake Model - Past, Present, Future

NASA Astrophysics Data System (ADS)

Smolka, Anselm; Schneider, John; Stein, Ross

2014-05-01

Source Models • Ground Motion (Attenuation) Models • Physical Exposure Models • Physical Vulnerability Models • Composite Index Models (social vulnerability, resilience, indirect loss) • Repository of national hazard models • Uniform global hazard model Armed with these tools and databases, stakeholders worldwide will then be able to calculate, visualise and investigate earthquake risk, capture new data and to share their findings for joint learning. Earthquake hazard information will be able to be combined with data on exposure (buildings, population) and data on their vulnerability, for risk assessment around the globe. Furthermore, for a truly integrated view of seismic risk, users will be able to add social vulnerability and resilience indices and estimate the costs and benefits of different risk management measures. Having finished its first five-year Work Program at the end of 2013, GEM has entered into its second five-year Work Program 2014-2018. Beyond maintaining and enhancing the products developed in Work Program 1, the second phase will have a stronger focus on regional hazard and risk activities, and on seeing GEM products used for risk assessment and risk management practice at regional, national and local scales. Furthermore GEM intends to partner with similar initiatives underway for other natural perils, which together are needed to meet the need for advanced risk assessment methods, tools and data to underpin global disaster risk reduction efforts under the Hyogo Framework for Action #2 to be launched in Sendai/Japan in spring 2015

Earthquake damage history in Israel and its close surrounding - evaluation of spatial and temporal patterns

NASA Astrophysics Data System (ADS)

Zohar, Motti; Salamon, Amos; Rubin, Rehav

2017-01-01

Israel was hit by destructive earthquakes many times in the course of history. To properly understand the hazard and support effective preparedness towards future earthquakes, we examined the spatial and temporal distribution of the resulted damage. We described in detail our systematic approach to searching the available literature, collecting the data and screening the authenticity of that information. We used GIS (Geographic Information System) to map and evaluate the distribution of the damage and to search for recurring patterns. Overall, it is found that 186 localities were hit, 54 of them at least twice. We also found that Israel was affected by 4, 17, 8 and 2 damaging earthquakes that originated, respectively, from the southern, central, central-northern and northern parts of the Dead Sea Transform (DST). The temporal appearance of the northern earthquakes is clustered; the central earthquakes are more regular in time, whereas no damage from the north-central and the central quakes, with the exception of the year 363 earthquake, seems to have occurred south of the Dead Sea region. Analyzing the distribution of the damage, we realized that the number of the damage reports reflects only half of the incidents that actually happened, attesting to incompleteness of the historical catalogue. Jerusalem is the most reported city with 14 entries, followed by Akko (Acre), Tiberias, Nablus and Tyre with 8, 7, 7 and 6 reports, respectively. In general, localities in the Galilee and north of it suffered more severely than localities in central Israel with the exception of Nablus and the localities along the coastal plain of Israel, most probably due to local site effects. For the sake of hazard management, these observations should be considered for future planning and risk mitigation.

Tsunami Hazard Assessment of Coastal South Africa Based on Mega-Earthquakes of Remote Subduction Zones

NASA Astrophysics Data System (ADS)

Kijko, Andrzej; Smit, Ansie; Papadopoulos, Gerassimos A.; Novikova, Tatyana

2018-04-01

After the mega-earthquakes and concomitant devastating tsunamis in Sumatra (2004) and Japan (2011), we launched an investigation into the potential risk of tsunami hazard to the coastal cities of South Africa. This paper presents the analysis of the seismic hazard of seismogenic sources that could potentially generate tsunamis, as well as the analysis of the tsunami hazard to coastal areas of South Africa. The subduction zones of Makran, South Sandwich Island, Sumatra, and the Andaman Islands were identified as possible sources of mega-earthquakes and tsunamis that could affect the African coast. Numerical tsunami simulations were used to investigate the realistic and worst-case scenarios that could be generated by these subduction zones. The simulated tsunami amplitudes and run-up heights calculated for the coastal cities of Cape Town, Durban, and Port Elizabeth are relatively small and therefore pose no real risk to the South African coast. However, only distant tsunamigenic sources were considered and the results should therefore be viewed as preliminary.

Tsunami Hazard Assessment of Coastal South Africa Based on Mega-Earthquakes of Remote Subduction Zones

NASA Astrophysics Data System (ADS)

Kijko, Andrzej; Smit, Ansie; Papadopoulos, Gerassimos A.; Novikova, Tatyana

2017-11-01

After the mega-earthquakes and concomitant devastating tsunamis in Sumatra (2004) and Japan (2011), we launched an investigation into the potential risk of tsunami hazard to the coastal cities of South Africa. This paper presents the analysis of the seismic hazard of seismogenic sources that could potentially generate tsunamis, as well as the analysis of the tsunami hazard to coastal areas of South Africa. The subduction zones of Makran, South Sandwich Island, Sumatra, and the Andaman Islands were identified as possible sources of mega-earthquakes and tsunamis that could affect the African coast. Numerical tsunami simulations were used to investigate the realistic and worst-case scenarios that could be generated by these subduction zones. The simulated tsunami amplitudes and run-up heights calculated for the coastal cities of Cape Town, Durban, and Port Elizabeth are relatively small and therefore pose no real risk to the South African coast. However, only distant tsunamigenic sources were considered and the results should therefore be viewed as preliminary.

GIA induced intraplate seismicity in northern Central Europe

NASA Astrophysics Data System (ADS)

Brandes, Christian; Steffen, Holger; Steffen, Rebekka; Wu, Patrick

2015-04-01

can be regarded as a kind of aftershock sequence of the GIA induced-seismicity. References Leydecker, G. and Kopera, J.R. Seismological hazard assessment for a site in Northern Germany, an area of low seismicity. Engineering Geology 52, 293-304 (1999). Leydecker, G. Erdbebenkatalog für die Bundesrepublik Deutschland mit Randgebieten für die Jahre 800-2008. Geologisches Jahrbuch Reihe E, 198 pp., (2011) Liu, M., Stein, S. and Wang, H. 2000 years of migrating earthquakes in north China: How earthquakes in midcontinents differ from those at plate boundaries. Lithosphere 3, 128-132, (2011).

Research in seismology and earthquake engineering in Venezuela

USGS Publications Warehouse

Urbina, L.; Grases, J.

1983-01-01

After the July 29, 1967, damaging earthquake (with a moderate magnitude of 6.3) caused widespread damage to the northern coastal area of Venezuela and to the Caracas Valley, the Venezuelan Government decided to establish a Presidential Earthquake Commission. This commission undertook the task of coordinating the efforts to study the after-effects of the earthquake. The July 1967 earthquake claimed numerous lives and caused extensive damage to the capital of Venezuela. In 1968, the U.S Geological Survey conducted a seismological field study in the northern coastal area and in the Caracas Valley of Venezuela. the objective was to study the area that sustained severe, moderate, and no damage to structures. A reported entitled Ground Amplification Studies in Earthquake Damage Areas: The Caracas Earthquake of 1967 documented, for the first time, short-period seismic wave ground-motion amplifications in the Caracas Valley. Figure 1 shows the area of severe damage in the Los Palos Grantes suburb and the correlation with depth of alluvium and the arabic numbers denote the ground amplification factor at each site in the area. the Venezuelan Government initiated many programs to study in detail the damage sustained and to investigate the ongoing construction practices. These actions motivated professionals in the academic, private, and Government sectors to develops further capabilities and self-sufficiency in the fields of engineering and seismology. Allocation of funds was made to assist in training professionals and technicians and in developing new seismological stations and new programs at the national level in earthquake engineering and seismology. A brief description of the ongoing programs in Venezuela is listed below. these programs are being performed by FUNVISIS and by other national organizations listed at the end of this article.   

The Development of an Earthquake Preparedness Plan for a Child Care Center in a Geologically Hazardous Region.

ERIC Educational Resources Information Center

Wokurka, Linda

The director of a child care center at a community college in California developed an earthquake preparedness plan for the center which met state and local requirements for earthquake preparedness at schools. The plan consisted of: (1) the identification and reduction of nonstructural hazards in classrooms, office, and staff rooms; (2) storage of…

East Meets West: An Earthquake in India Helps Hazard Assessment in the Central United States

USGS Publications Warehouse

,

2002-01-01

Although geographically distant, the State of Gujarat in India bears many geological similarities to the Mississippi Valley in the Central United States. The Mississippi Valley contains the New Madrid seismic zone that, during the winter of 1811-1812, produced the three largest historical earthquakes ever in the continental United States and remains the most seismically active region east of the Rocky Mountains. Large damaging earthquakes are rare in ‘intraplate’ settings like New Madrid and Gujarat, far from the boundaries of the world’s great tectonic plates. Long-lasting evidence left by these earthquakes is subtle (fig. 1). Thus, each intraplate earthquake provides unique opportunities to make huge advances in our ability to assess and understand the hazards posed by such events.

Have recent earthquakes exposed flaws in or misunderstandings of probabilistic seismic hazard analysis?

USGS Publications Warehouse

Hanks, Thomas C.; Beroza, Gregory C.; Toda, Shinji

2012-01-01

In a recent Opinion piece in these pages, Stein et al. (2011) offer a remarkable indictment of the methods, models, and results of probabilistic seismic hazard analysis (PSHA). The principal object of their concern is the PSHA map for Japan released by the Japan Headquarters for Earthquake Research Promotion (HERP), which is reproduced by Stein et al. (2011) as their Figure 1 and also here as our Figure 1. It shows the probability of exceedance (also referred to as the “hazard”) of the Japan Meteorological Agency (JMA) intensity 6–lower (JMA 6–) in Japan for the 30-year period beginning in January 2010. JMA 6– is an earthquake-damage intensity measure that is associated with fairly strong ground motion that can be damaging to well-built structures and is potentially destructive to poor construction (HERP, 2005, appendix 5). Reiterating Geller (2011, p. 408), Stein et al. (2011, p. 623) have this to say about Figure 1: The regions assessed as most dangerous are the zones of three hypothetical “scenario earthquakes” (Tokai, Tonankai, and Nankai; see map). However, since 1979, earthquakes that caused 10 or more fatalities in Japan actually occurred in places assigned a relatively low probability. This discrepancy—the latest in a string of negative results for the characteristic model and its cousin the seismic-gap model—strongly suggest that the hazard map and the methods used to produce it are flawed and should be discarded. Given the central role that PSHA now plays in seismic risk analysis, performance-based engineering, and design-basis ground motions, discarding PSHA would have important consequences. We are not persuaded by the arguments of Geller (2011) and Stein et al. (2011) for doing so because important misunderstandings about PSHA seem to have conditioned them. In the quotation above, for example, they have confused important differences between earthquake-occurrence observations and ground-motion hazard calculations.

Northern California Earthquake Data Center: Data Sets and Data Services

NASA Astrophysics Data System (ADS)

Neuhauser, D. S.; Allen, R. M.; Zuzlewski, S.

2015-12-01

The Northern California Earthquake Data Center (NCEDC) provides a permanent archive and real-time data distribution services for a unique and comprehensive data set of seismological and geophysical data sets encompassing northern and central California. We provide access to over 85 terabytes of continuous and event-based time series data from broadband, short-period, strong motion, and strain sensors as well as continuous and campaign GPS data at both standard and high sample rates. The Northen California Seismic System (NCSS), operated by UC Berkeley and USGS Menlo Park, has recorded over 900,000 events from 1984 to the present, and the NCEDC serves catalog, parametric information, moment tensors and first motion mechanisms, and time series data for these events. We also serve event catalogs, parametric information, and event waveforms for DOE enhanced geothermal system monitoring in northern California and Nevada. The NCEDC provides a several ways for users to access these data. The most recent development are web services, which provide interactive, command-line, or program-based workflow access to data. Web services use well-established server and client protocols and RESTful software architecture that allow users to easily submit queries and receive the requested data in real-time rather than through batch or email-based requests. Data are returned to the user in the appropriate format such as XML, RESP, simple text, or MiniSEED depending on the service and selected output format. The NCEDC supports all FDSN-defined web services as well as a number of IRIS-defined and NCEDC-defined services. We also continue to support older email-based and browser-based access to data. NCEDC data and web services can be found at http://www.ncedc.org and http://service.ncedc.org.

Comparision of the different probability distributions for earthquake hazard assessment in the North Anatolian Fault Zone

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yilmaz, Şeyda, E-mail: seydayilmaz@ktu.edu.tr; Bayrak, Erdem, E-mail: erdmbyrk@gmail.com; Bayrak, Yusuf, E-mail: bayrak@ktu.edu.tr

In this study we examined and compared the three different probabilistic distribution methods for determining the best suitable model in probabilistic assessment of earthquake hazards. We analyzed a reliable homogeneous earthquake catalogue between a time period 1900-2015 for magnitude M ≥ 6.0 and estimated the probabilistic seismic hazard in the North Anatolian Fault zone (39°-41° N 30°-40° E) using three distribution methods namely Weibull distribution, Frechet distribution and three-parameter Weibull distribution. The distribution parameters suitability was evaluated Kolmogorov-Smirnov (K-S) goodness-of-fit test. We also compared the estimated cumulative probability and the conditional probabilities of occurrence of earthquakes for different elapsed timemore » using these three distribution methods. We used Easyfit and Matlab software to calculate these distribution parameters and plotted the conditional probability curves. We concluded that the Weibull distribution method was the most suitable than other distribution methods in this region.« less

GPS and seismic constraints on the M = 7.3 2009 Swan Islands earthquake: implications for stress changes along the Motagua fault and other nearby faults

NASA Astrophysics Data System (ADS)

Graham, Shannon E.; DeMets, Charles; DeShon, Heather R.; Rogers, Robert; Maradiaga, Manuel Rodriguez; Strauch, Wilfried; Wiese, Klaus; Hernandez, Douglas

2012-09-01

We use measurements at 35 GPS stations in northern Central America and 25 seismometers at teleseismic distances to estimate the distribution of slip, source time function and Coulomb stress changes of the Mw = 7.3 2009 May 28, Swan Islands fault earthquake. This event, the largest in the region for several decades, ruptured the offshore continuation of the seismically hazardous Motagua fault of Guatemala, the site of the destructive Ms = 7.5 earthquake in 1976. Measured GPS offsets range from 308 millimetres at a campaign site in northern Honduras to 6 millimetres at five continuous sites in El Salvador. Separate inversions of geodetic and seismic data both indicate that up to ˜1 m of coseismic slip occurred along a ˜250-km-long rupture zone between the island of Roatan and the eastern limit of the 1976 M = 7.5 Motagua fault earthquake in Guatemala. Evidence for slip ˜250 km west of the epicentre is corroborated independently by aftershocks recorded by a local seismic network and by the high concentration of damage to structures in areas of northern Honduras adjacent to the western limit of the rupture zone. Coulomb stresses determined from the coseismic slip distribution resolve a maximum of 1 bar of stress transferred to the seismically hazardous Motagua fault and further indicate unclamping of normal faults along the northern shore of Honduras, where two M > 5 normal-faulting earthquakes and numerous small earthquakes were triggered by the main shock.

Earthquake Hazard Class Mapping by Parcel in Las Vegas Valley

NASA Astrophysics Data System (ADS)

Pancha, A.; Pullammanappallil, S.; Louie, J. N.; Hellmer, W. K.

2011-12-01

Clark County, Nevada completed the very first effort in the United States to map earthquake hazard class systematically through an entire urban area. The map is used in development and disaster response planning, in addition to its direct use for building code implementation and enforcement. The County contracted with the Nevada System of Higher Education to classify about 500 square miles including urban Las Vegas Valley, and exurban areas considered for future development. The Parcel Map includes over 10,000 surface-wave array measurements accomplished over three years using Optim's SeisOpt° ReMi measurement and processing techniques adapted for large scale data. These array measurements classify individual parcels on the NEHRP hazard scale. Parallel "blind" tests were conducted at 93 randomly selected sites. The rms difference between the Vs30 values yielded by the blind data and analyses and the Parcel Map analyses is 4.92%. Only six of the blind-test sites showed a difference with a magnitude greater than 10%. We describe a "C+" Class for sites with Class B average velocities but soft surface soil. The measured Parcel Map shows a clearly definable C+ to C boundary on the west side of the Valley. The C to D boundary is much more complex. Using the parcel map in computing shaking in the Valley for scenario earthquakes is crucial for obtaining realistic predictions of ground motions.

Earthquakes, September-October 1984

USGS Publications Warehouse

Person, W.J.

1985-01-01

In the United States, Wyoming experienced a couple of moderate earthquakes, and off the coast of northern California, a strong earthquake shook much of the northern coast of California and parts of the Oregon coast. 

The "Tsunami Earthquake" of 13 April 1923 in Northern Kamchatka: Seismological and Hydrodynamic Investigations

NASA Astrophysics Data System (ADS)

Salaree, Amir; Okal, Emile A.

2018-04-01

We present a seismological and hydrodynamic investigation of the earthquake of 13 April 1923 at Ust'-Kamchatsk, Northern Kamchatka, which generated a more powerful and damaging tsunami than the larger event of 03 February 1923, thus qualifying as a so-called "tsunami earthquake". On the basis of modern relocations, we suggest that it took place outside the fault area of the mainshock, across the oblique Pacific-North America plate boundary, a model confirmed by a limited dataset of mantle waves, which also confirms the slow nature of the source, characteristic of tsunami earthquakes. However, numerical simulations for a number of legitimate seismic models fail to reproduce the sharply peaked distribution of tsunami wave amplitudes reported in the literature. By contrast, we can reproduce the distribution of reported wave amplitudes using an underwater landslide as a source of the tsunami, itself triggered by the earthquake inside the Kamchatskiy Bight.

Stability assessment of structures under earthquake hazard through GRID technology

NASA Astrophysics Data System (ADS)

Prieto Castrillo, F.; Boton Fernandez, M.

2009-04-01

This work presents a GRID framework to estimate the vulnerability of structures under earthquake hazard. The tool has been designed to cover the needs of a typical earthquake engineering stability analysis; preparation of input data (pre-processing), response computation and stability analysis (post-processing). In order to validate the application over GRID, a simplified model of structure under artificially generated earthquake records has been implemented. To achieve this goal, the proposed scheme exploits the GRID technology and its main advantages (parallel intensive computing, huge storage capacity and collaboration analysis among institutions) through intensive interaction among the GRID elements (Computing Element, Storage Element, LHC File Catalogue, federated database etc.) The dynamical model is described by a set of ordinary differential equations (ODE's) and by a set of parameters. Both elements, along with the integration engine, are encapsulated into Java classes. With this high level design, subsequent improvements/changes of the model can be addressed with little effort. In the procedure, an earthquake record database is prepared and stored (pre-processing) in the GRID Storage Element (SE). The Metadata of these records is also stored in the GRID federated database. This Metadata contains both relevant information about the earthquake (as it is usual in a seismic repository) and also the Logical File Name (LFN) of the record for its later retrieval. Then, from the available set of accelerograms in the SE, the user can specify a range of earthquake parameters to carry out a dynamic analysis. This way, a GRID job is created for each selected accelerogram in the database. At the GRID Computing Element (CE), displacements are then obtained by numerical integration of the ODE's over time. The resulting response for that configuration is stored in the GRID Storage Element (SE) and the maximum structure displacement is computed. Then, the corresponding

Initiation process of earthquakes and its implications for seismic hazard reduction strategy.

PubMed Central

Kanamori, H

1996-01-01

For the average citizen and the public, "earthquake prediction" means "short-term prediction," a prediction of a specific earthquake on a relatively short time scale. Such prediction must specify the time, place, and magnitude of the earthquake in question with sufficiently high reliability. For this type of prediction, one must rely on some short-term precursors. Examinations of strain changes just before large earthquakes suggest that consistent detection of such precursory strain changes cannot be expected. Other precursory phenomena such as foreshocks and nonseismological anomalies do not occur consistently either. Thus, reliable short-term prediction would be very difficult. Although short-term predictions with large uncertainties could be useful for some areas if their social and economic environments can tolerate false alarms, such predictions would be impractical for most modern industrialized cities. A strategy for effective seismic hazard reduction is to take full advantage of the recent technical advancements in seismology, computers, and communication. In highly industrialized communities, rapid earthquake information is critically important for emergency services agencies, utilities, communications, financial companies, and media to make quick reports and damage estimates and to determine where emergency response is most needed. Long-term forecast, or prognosis, of earthquakes is important for development of realistic building codes, retrofitting existing structures, and land-use planning, but the distinction between short-term and long-term predictions needs to be clearly communicated to the public to avoid misunderstanding. Images Fig. 8 PMID:11607657

Initiation process of earthquakes and its implications for seismic hazard reduction strategy.

PubMed

Kanamori, H

1996-04-30

For the average citizen and the public, "earthquake prediction" means "short-term prediction," a prediction of a specific earthquake on a relatively short time scale. Such prediction must specify the time, place, and magnitude of the earthquake in question with sufficiently high reliability. For this type of prediction, one must rely on some short-term precursors. Examinations of strain changes just before large earthquakes suggest that consistent detection of such precursory strain changes cannot be expected. Other precursory phenomena such as foreshocks and nonseismological anomalies do not occur consistently either. Thus, reliable short-term prediction would be very difficult. Although short-term predictions with large uncertainties could be useful for some areas if their social and economic environments can tolerate false alarms, such predictions would be impractical for most modern industrialized cities. A strategy for effective seismic hazard reduction is to take full advantage of the recent technical advancements in seismology, computers, and communication. In highly industrialized communities, rapid earthquake information is critically important for emergency services agencies, utilities, communications, financial companies, and media to make quick reports and damage estimates and to determine where emergency response is most needed. Long-term forecast, or prognosis, of earthquakes is important for development of realistic building codes, retrofitting existing structures, and land-use planning, but the distinction between short-term and long-term predictions needs to be clearly communicated to the public to avoid misunderstanding.

A GPS Modeling Study of Earthquakes and Deformation in Northern Central America and along the Middle America Trench: 1999 to 2017

NASA Astrophysics Data System (ADS)

Ellis, Andria P.

Northern Central America is a tectonically complicated region prone to hazardous earthquakes due to the confluence of the Motagua-Polochic fault zone with the Middle America trench and strike-slip faults in the Central America volcanic arc. These three major fault zones converge at the western end of the Caribbean plate where the Cocos plate subducts under the North America and Caribbean plates. Literature from the 1970s and 1980s focused on whether a discrete North America-Caribbean-Cocos plate triple junction existed, and how the relative motions of the upper North America and Caribbean plates were accommodated. The discovery of a fourth major crustal block, the Central America forearc sliver, from seismic and geodetic observations made a three-plate triple junction geometrically impossible and introduced a new set of questions related to how deformation of the upper plate accommodates relative movements between the Caribbean plate, North America plate, and Central America forearc sliver where they intersect in the upper plate. My dissertation uses GPS and numerical modeling to measure and quantify earthquake transients and crustal deformation related to fault interactions in northern Central America and consists of three related chapters. The first chapter of my dissertation is a geodetic study of a M w = 7.4 subduction zone earthquake that occurred in 2012 offshore from our Guatemala GPS (Global Positioning System) network. For this study, I inverted coseismic site offsets and postseismic amplitudes to determine best-fitting coseismic and afterslip rupture distributions on the Middle America trench. I also determined the maximum likely viscoelastic deformation for the earthquake to test whether the transient postseismic deformation was dominated by fault afterslip or viscoelastic flow. This work was published in Geophysical Journal International in January 2015. The second chapter of my dissertation derives a new 200+ site GPS velocity field for northern

The ``exceptional'' earthquake of 3 January 1117 in the Verona area (northern Italy): A critical time review and detection of two lost earthquakes (lower Germany and Tuscany)

NASA Astrophysics Data System (ADS)

Guidoboni, Emanuela; Comastri, Alberto; Boschi, Enzo

2005-12-01

In the seismological literature the 3 January 1117 earthquake represents an interesting case study, both for the sheer size of the area in which that event is recorded by the monastic sources of the 12th century, and for the amount of damage mentioned. The 1117 event has been added to the earthquake catalogues of up to five European countries (Italy, France, Belgium, Switzerland, the Iberian peninsula), and it is the largest historical earthquake for northern Italy. We have analyzed the monastic time system in the 12th century and, by means of a comparative analysis of the sources, have correlated the two shocks mentioned (in the night and in the afternoon of 3 January) to territorial effects, seeking to make the overall picture reported for Europe more consistent. The connection between the linguistic indications and the localization of the effects has allowed us to shed light, with a reasonable degree of approximation, upon two previously little known earthquakes, probably generated by a sequence of events. A first earthquake in lower Germany (I0 (epicentral intensity) VII-VIII MCS (Mercalli, Cancani, Sieberg), M 6.4) preceded the far more violent one in northern Italy (Verona area) by about 12-13 hours. The second event is the one reported in the literature. We have put forward new parameters for this Veronese earthquake (I0 IX MCS, M 7.0). A third earthquake is independently recorded in the northwestern area of Tuscany (Imax VII-VIII MCS), but for the latter event the epicenter and magnitude cannot be evaluated.

Source of 1629 Banda Mega-Thrust Earthquake and Tsunami: Implications for Tsunami Hazard Evaluation in Eastern Indonesia

NASA Astrophysics Data System (ADS)

Major, J. R.; Liu, Z.; Harris, R. A.; Fisher, T. L.

2011-12-01

Using Dutch records of geophysical events in Indonesia over the past 400 years, and tsunami modeling, we identify tsunami sources that have caused severe devastation in the past and are likely to reoccur in the near future. The earthquake history of Western Indonesia has received much attention since the 2004 Sumatra earthquakes and subsequent events. However, strain rates along a variety of plate boundary segments are just as high in eastern Indonesia where the earthquake history has not been investigated. Due to the rapid population growth in this region it is essential and urgent to evaluate its earthquake and tsunami hazards. Arthur Wichmann's 'Earthquakes of the Indian Archipelago' shows that there were 30 significant earthquakes and 29 tsunami between 1629 to 1877. One of the largest and best documented is the great earthquake and tsunami effecting the Banda islands on 1 August, 1629. It caused severe damage from a 15 m tsunami that arrived at the Banda Islands about a half hour after the earthquake. The earthquake was also recorded 230 km away in Ambon, but no tsunami is mentioned. This event was followed by at least 9 years of aftershocks. The combination of these observations indicates that the earthquake was most likely a mega-thrust event. We use a numerical simulation of the tsunami to locate the potential sources of the 1629 mega-thrust event and evaluate the tsunami hazard in Eastern Indonesia. The numerical simulation was tested to establish the tsunami run-up amplification factor for this region by tsunami simulations of the 1992 Flores Island (Hidayat et al., 1995) and 2006 Java (Katoet al., 2007) earthquake events. The results yield a tsunami run-up amplification factor of 1.5 and 3, respectively. However, the Java earthquake is a unique case of slow rupture that was hardly felt. The fault parameters of recent earthquakes in the Banda region are used for the models. The modeling narrows the possibilities of mega-thrust events the size of the one

Understanding Earthquake Hazard & Disaster in Himalaya - A Perspective on Earthquake Forecast in Himalayan Region of South Central Tibet

NASA Astrophysics Data System (ADS)

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

2010-12-01

It is not only the basic understanding of the phenomenon of earthquake, its resistance offered by the designed structure, but the understanding of the socio-economic factors, engineering properties of the indigenous materials, local skill and technology transfer models are also of vital importance. It is important that the engineering aspects of mitigation should be made a part of public policy documents. Earthquakes, therefore, are and were thought of as one of the worst enemies of mankind. Due to the very nature of release of energy, damage is evident which, however, will not culminate in a disaster unless it strikes a populated area. The word mitigation may be defined as the reduction in severity of something. The Earthquake disaster mitigation, therefore, implies that such measures may be taken which help reduce severity of damage caused by earthquake to life, property and environment. While “earthquake disaster mitigation” usually refers primarily to interventions to strengthen the built environment, and “earthquake protection” is now considered to include human, social and administrative aspects of reducing earthquake effects. It should, however, be noted that reduction of earthquake hazards through prediction is considered to be the one of the effective measures, and much effort is spent on prediction strategies. While earthquake prediction does not guarantee safety and even if predicted correctly the damage to life and property on such a large scale warrants the use of other aspects of mitigation. While earthquake prediction may be of some help, mitigation remains the main focus of attention of the civil society. Present study suggests that anomalous seismic activity/ earthquake swarm existed prior to the medium size earthquakes in the Nepal Himalaya. The mainshocks were preceded by the quiescence period which is an indication for the occurrence of future seismic activity. In all the cases, the identified episodes of anomalous seismic activity were

Gradual unlocking of plate boundary controlled initiation of the 2014 Iquique earthquake.

PubMed

Schurr, Bernd; Asch, Günter; Hainzl, Sebastian; Bedford, Jonathan; Hoechner, Andreas; Palo, Mauro; Wang, Rongjiang; Moreno, Marcos; Bartsch, Mitja; Zhang, Yong; Oncken, Onno; Tilmann, Frederik; Dahm, Torsten; Victor, Pia; Barrientos, Sergio; Vilotte, Jean-Pierre

2014-08-21

On 1 April 2014, Northern Chile was struck by a magnitude 8.1 earthquake following a protracted series of foreshocks. The Integrated Plate Boundary Observatory Chile monitored the entire sequence of events, providing unprecedented resolution of the build-up to the main event and its rupture evolution. Here we show that the Iquique earthquake broke a central fraction of the so-called northern Chile seismic gap, the last major segment of the South American plate boundary that had not ruptured in the past century. Since July 2013 three seismic clusters, each lasting a few weeks, hit this part of the plate boundary with earthquakes of increasing peak magnitudes. Starting with the second cluster, geodetic observations show surface displacements that can be associated with slip on the plate interface. These seismic clusters and their slip transients occupied a part of the plate interface that was transitional between a fully locked and a creeping portion. Leading up to this earthquake, the b value of the foreshocks gradually decreased during the years before the earthquake, reversing its trend a few days before the Iquique earthquake. The mainshock finally nucleated at the northern end of the foreshock area, which skirted a locked patch, and ruptured mainly downdip towards higher locking. Peak slip was attained immediately downdip of the foreshock region and at the margin of the locked patch. We conclude that gradual weakening of the central part of the seismic gap accentuated by the foreshock activity in a zone of intermediate seismic coupling was instrumental in causing final failure, distinguishing the Iquique earthquake from most great earthquakes. Finally, only one-third of the gap was broken and the remaining locked segments now pose a significant, increased seismic hazard with the potential to host an earthquake with a magnitude of >8.5.

Early results from the Northern Gulf of Mexico Ecosystem Change and Hazard Susceptibility Project

USGS Publications Warehouse

Brock, John C.; Lavoie, Dawn L.; Poore, Richard Z.

2011-01-01

The northern Gulf of Mexico coastal region and its diverse ecosystems are threatened by population and development pressure and by the impacts of rising sea level and severe storms such as the series of hurricanes that has impacted the northern Gulf in recent years. In response to the complex management issues facing the region, the U.S. Geological Survey (USGS) organized a multidisciplinary research program to coordinate the activities of USGS and other scientists working in the northern Gulf of Mexico region (fig. 1). The Northern Gulf of Mexico (NGOM) Ecosystem Change and Hazard Susceptibility Project aims to develop a thorough understanding of the dynamic coastal ecosystems on the northern Gulf coast, the impact of human activities on these ecosystems, and the vulnerability of ecosystems and human communities to more frequent and more intense hurricanes in the future. A special issue of Geo-Marine Letters published in December 2009 is devoted to early results of studies completed as part of this project. These studies, which have been conducted at sites throughout the northern Gulf region, from the Chandeleur Islands to Apalachicola Bay, have focused on three themes: (1) The underlying geologic framework that exerts controls over coastal processes (2) The impact of human activities on nearshore water quality (3) Hurricanes and associated effects

Scenario-Based Tsunami Hazard Assessment from Earthquake and Landslide Sources for Eastern Sicily, Italy

NASA Astrophysics Data System (ADS)

Tinti, S.; Armigliato, A.; Pagnoni, G.; Paparo, M. A.; Zaniboni, F.

2016-12-01

Eastern Sicily was theatre of the most damaging tsunamis that ever struck Italy, such as the 11 January 1693 and the 28 December 1908 tsunamis. Tectonic studies and paleotsunami investigations extended historical records of tsunami occurrence back of several thousands of years. Tsunami sources relevant for eastern Sicily are both local and remote, the latter being located in the Ionian Greece and in the Western Hellenic Arc. Here in 365 A.D. a large earthquake generated a tsunami that was seen in the whole eastern and central Mediterranean including the Sicilian coasts. The objective of this study is the evaluation of tsunami hazard along the coast of eastern Sicily, central Mediterranean, Italy via a scenario-based technique, which has been preferred to the PTHA approach because, when dealing with tsunamis induced by landslides, uncertainties are usually so large to undermine the PTHA results. Tsunamis of earthquake and landslide origin are taken into account for the entire coast of Sicily, from the Messina to the Siracusa provinces. Landslides are essentially local sources and can occur underwater along the unstable flanks of the Messina Straits or along the steep slopes of the Hyblaean-Malta escarpment. The method is based on a two-step procedure. After a preliminary step where very many earthquake and landslide sources are taken into account and tsunamis are computed on a low-resolution grid, the worst-case scenarios are selected and tsunamis are simulated on a finer-resolution grid allowing for a better calculation of coastal wave height and tsunami penetration. The final result of our study is given in the form of aggregate fields computed from individual scenarios. Also interesting is the contribution of the various tsunami sources in different localities along the coast. It is found that the places with the highest level of hazard are the low lands of La Playa south of Catania and of the Bay of Augusta, which is in agreement also with historical

Preparation of Synthetic Earthquake Catalogue and Tsunami Hazard Curves in Marmara Sea using Monte Carlo Simulations

NASA Astrophysics Data System (ADS)

Bayraktar, Başak; Özer Sözdinler, Ceren; Necmioǧlu, Öcal; Meral Özel, Nurcan

2017-04-01

The Marmara Sea and its surrounding is one of the most populated areas in Turkey. Many densely populated cities, such as megacity Istanbul with a population of more than 14 million, a great number of industrial facilities in largest capacity and potential, refineries, ports and harbors are located along the coasts of Marmara Sea. The region is highly seismically active. There has been a wide range of studies in this region regarding the fault mechanisms, seismic activities, earthquakes and triggered tsunamis in the Sea of Marmara. The historical documents reveal that the region has been experienced many earthquakes and tsunamis in the past. According to Altinok et al. (2011), 35 tsunami events happened in Marmara Sea between BC 330 and 1999. As earthquakes are expected in Marmara Sea with the break of segments of North Anatolian Fault (NAF) in the future, the region should be investigated in terms of the possibility of tsunamis by the occurrence of earthquakes in specific return periods. This study aims to make probabilistic tsunami hazard analysis in Marmara Sea. For this purpose, the possible sources of tsunami scenarios are specified by compiling the earthquake catalogues, historical records and scientific studies conducted in the region. After compiling all this data, a synthetic earthquake and tsunami catalogue are prepared using Monte Carlo simulations. For specific return periods, the possible epicenters, rupture lengths, widths and displacements are determined with Monte Carlo simulations assuming the angles of fault segments as deterministic. For each earthquake of synthetic catalogue, the tsunami wave heights will be calculated at specific locations along Marmara Sea. As a further objective, this study will determine the tsunami hazard curves for specific locations in Marmara Sea including the tsunami wave heights and their probability of exceedance. This work is supported by SATREPS-MarDim Project (Earthquake and Tsunami Disaster Mitigation in the

Slab Geometry and Deformation in the Northern Nazca Subduction Zone Inferred From The Relocation and Focal mechanisms of Intermediate-Depth Earthquakes

NASA Astrophysics Data System (ADS)

Chang, Y.; Warren, L. M.; Prieto, G. A.

2015-12-01

In the northern Nazca subduction zone, the Nazca plate is subducting to the east beneath the South American Plate. At ~5.6ºN, the subducting plate has a 240-km east-west offset associated with a slab tear, called the Caldas tear, that separates the northern and southern segments. Our study seeks to better define the slab geometry and deformation in the southern segment, which has a high rate of intermediate-depth earthquakes (50-300 km) between 3.6ºN and 5.2ºN in the Cauca cluster. From Jan 2010 to Mar 2014, 228 intermediate-depth earthquakes in the Cauca cluster with local magnitude Ml 2.5-4.7 were recorded by 65 seismic stations of the Colombian National Seismic Network. We review and, if necessary, adjust the catalog P and S wave arrival picks. We use the travel times to relocate the earthquakes using a double difference relocation method. For earthquakes with Ml ≥3.8, we also use waveform modeling to compute moment tensors . The distribution of earthquake relocations shows an ~15-km-thick slab dipping to the SE. The dip angle increases from 20º at the northern edge of the cluster to 38º at the southern edge. Two concentrated groups of earthquakes extend ~40 km vertically above the general downdip trend, with a 20 km quiet gap between them at ~100 km depth. The earthquakes in the general downdip seismic zone have downdip compressional axes, while earthquakes close to the quiet gap and in the concentrated groups have an oblique component. The general decrease in slab dip angle to the north may be caused by mantle flow through the Caldas tear. The seismicity gap in the slab may be associated with an active deformation zone and the concentrated groups of earthquakes with oblique focal mechanisms could be due to a slab fold.

Challenges to communicate risks of human-caused earthquakes

NASA Astrophysics Data System (ADS)

Klose, C. D.

2014-12-01

The awareness of natural hazards has been up-trending in recent years. In particular, this is true for earthquakes, which increase in frequency and magnitude in regions that normally do not experience seismic activity. In fact, one of the major concerns for many communities and businesses is that humans today seem to cause earthquakes due to large-scale shale gas production, dewatering and flooding of mines and deep geothermal power production. Accordingly, without opposing any of these technologies it should be a priority of earth scientists who are researching natural hazards to communicate earthquake risks. This presentation discusses the challenges that earth scientists are facing to properly communicate earthquake risks, in light of the fact that human-caused earthquakes are an environmental change affecting only some communities and businesses. Communication channels may range from research papers, books and class room lectures to outreach events and programs, popular media events or even social media networks.

Upper-plate splay fault earthquakes along the Arakan subduction belt recorded by uplifted coral microatolls on northern Ramree Island, western Myanmar (Burma)

NASA Astrophysics Data System (ADS)

Shyu, J. Bruce H.; Wang, Chung-Che; Wang, Yu; Shen, Chuan-Chou; Chiang, Hong-Wei; Liu, Sze-Chieh; Min, Soe; Aung, Lin Thu; Than, Oo; Tun, Soe Thura

2018-02-01

Upper-plate structures that splay out from the megathrusts are common features along major convergent plate boundaries. However, their earthquake and tsunami hazard potentials have not yet received significant attention. In this study, we identified at least one earthquake event that may have been produced by an upper-plate splay fault offshore western Myanmar, based on U-Th ages of uplifted coral microatolls. This event is likely an earthquake that was documented historically in C.E. 1848, with an estimated magnitude between 6.8 and 7.2 based on regional structural characteristics. Such magnitude is consistent with the observed co-seismic uplift amount of ∼0.5 m. Although these events are smaller in magnitude than events produced by megathrusts, they may produce higher earthquake and tsunami hazards for local coastal communities due to their proximity. Our results also indicate that earthquake events with co-seismic uplift along the coast may not necessarily produce a flight of marine terraces. Therefore, using only records of uplifted marine terraces as megathrust earthquake proxies may overlook the importance of upper-plate splay fault ruptures, and underestimate the overall earthquake frequency for future seismic and tsunami hazards along major subduction zones of the world.

Empirical ground-motion relations for subduction-zone earthquakes and their application to Cascadia and other regions

USGS Publications Warehouse

Atkinson, G.M.; Boore, D.M.

2003-01-01

Ground-motion relations for earthquakes that occur in subduction zones are an important input to seismic-hazard analyses in many parts of the world. In the Cascadia region (Washington, Oregon, northern California, and British Columbia), for example, there is a significant hazard from megathrust earthquakes along the subduction interface and from large events within the subducting slab. These hazards are in addition to the hazard from shallow earthquakes in the overlying crust. We have compiled a response spectra database from thousands of strong-motion recordings from events of moment magnitude (M) 5-8.3 occurring in subduction zones around the world, including both interface and in-slab events. The 2001 M 6.8 Nisqually and 1999 M 5.9 Satsop earthquakes are included in the database, as are many records from subduction zones in Japan (Kyoshin-Net data), Mexico (Guerrero data), and Central America. The size of the database is four times larger than that available for previous empirical regressions to determine ground-motion relations for subduction-zone earthquakes. The large dataset enables improved determination of attenuation parameters and magnitude scaling, for both interface and in-slab events. Soil response parameters are also better determined by the data. We use the database to develop global ground-motion relations for interface and in-slab earthquakes, using a maximum likelihood regression method. We analyze regional variability of ground-motion amplitudes across the global database and find that there are significant regional differences. In particular, amplitudes in Cascadia differ by more than a factor of 2 from those in Japan for the same magnitude, distance, event type, and National Earthquake Hazards Reduction Program (NEHRP) soil class. This is believed to be due to regional differences in the depth of the soil profile, which are not captured by the NEHRP site classification scheme. Regional correction factors to account for these differences are

Extending the ISC-GEM Global Earthquake Instrumental Catalogue

NASA Astrophysics Data System (ADS)

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.

Seismicity in the source areas of the 1896 and 1933 Sanriku earthquakes and implications for large near-trench earthquake faults

NASA Astrophysics Data System (ADS)

Obana, Koichiro; Nakamura, Yasuyuki; Fujie, Gou; Kodaira, Shuichi; Kaiho, Yuka; Yamamoto, Yojiro; Miura, Seiichi

2018-03-01

In the northern part of the Japan Trench, the 1933 Showa-Sanriku earthquake (Mw 8.4), an outer-trench, normal-faulting earthquake, occurred 37 yr after the 1896 Meiji-Sanriku tsunami earthquake (Mw 8.0), a shallow, near-trench, plate-interface rupture. Tsunamis generated by both earthquakes caused severe damage along the Sanriku coast. Precise locations of earthquakes in the source areas of the 1896 and 1933 earthquakes have not previously been obtained because they occurred at considerable distances from the coast in deep water beyond the maximum operational depth of conventional ocean bottom seismographs (OBSs). In 2015, we incorporated OBSs designed for operation in deep water (ultradeep OBSs) in an OBS array during two months of seismic observations in the source areas of the 1896 and 1933 Sanriku earthquakes to investigate the relationship of seismicity there to outer-rise normal-faulting earthquakes and near-trench tsunami earthquakes. Our analysis showed that seismicity during our observation period occurred along three roughly linear trench-parallel trends in the outer-trench region. Seismic activity along these trends likely corresponds to aftershocks of the 1933 Showa-Sanriku earthquake and the Mw 7.4 normal-faulting earthquake that occurred 40 min after the 2011 Tohoku-Oki earthquake. Furthermore, changes of the clarity of reflections from the oceanic Moho on seismic reflection profiles and low-velocity anomalies within the oceanic mantle were observed near the linear trends of the seismicity. The focal mechanisms we determined indicate that an extensional stress regime extends to about 40 km depth, below which the stress regime is compressional. These observations suggest that rupture during the 1933 Showa-Sanriku earthquake did not extend to the base of the oceanic lithosphere and that compound rupture of multiple or segmented faults is a more plausible explanation for that earthquake. The source area of the 1896 Meiji-Sanriku tsunami earthquake is

Turkish Compulsory Earthquake Insurance (TCIP)

NASA Astrophysics Data System (ADS)

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

2009-04-01

Through a World Bank project a government-sponsored Turkish Catastrophic Insurance Pool (TCIP) is created in 2000 with the essential aim of transferring the government's financial burden of replacing earthquake-damaged housing to international reinsurance and capital markets. Providing coverage to about 2.9 Million homeowners TCIP is the largest insurance program in the country with about 0.5 Billion USD in its own reserves and about 2.3 Billion USD in total claims paying capacity. The total payment for earthquake damage since 2000 (mostly small, 226 earthquakes) amounts to about 13 Million USD. The country-wide penetration rate is about 22%, highest in the Marmara region (30%) and lowest in the south-east Turkey (9%). TCIP is the sole-source provider of earthquake loss coverage up to 90,000 USD per house. The annual premium, categorized on the basis of earthquake zones type of structure, is about US90 for a 100 square meter reinforced concrete building in the most hazardous zone with 2% deductible. The earthquake engineering related shortcomings of the TCIP is exemplified by fact that the average rate of 0.13% (for reinforced concrete buildings) with only 2% deductible is rather low compared to countries with similar earthquake exposure. From an earthquake engineering point of view the risk underwriting (Typification of housing units to be insured, earthquake intensity zonation and the sum insured) of the TCIP needs to be overhauled. Especially for large cities, models can be developed where its expected earthquake performance (and consequently the insurance premium) can be can be assessed on the basis of the location of the unit (microzoned earthquake hazard) and basic structural attributes (earthquake vulnerability relationships). With such an approach, in the future the TCIP can contribute to the control of construction through differentiation of premia on the basis of earthquake vulnerability.

The 2011 Mineral, Virginia, earthquake and its significance for seismic hazards in eastern North America: overview and synthesis

USGS Publications Warehouse

Horton, J. Wright; Chapman, Martin C.; Green, Russell A.

2015-01-01

The earthquake and aftershocks occurred in crystalline rocks within Paleozoic thrust sheets of the Chopawamsic terrane. The main shock and majority of aftershocks delineated the newly named Quail fault zone in the subsurface, and shallow aftershocks defined outlying faults. The earthquake induced minor liquefaction sand boils, but notably there was no evidence of a surface fault rupture. Recurrence intervals, and evidence for larger earthquakes in the Quaternary in this area, remain important unknowns. This event, along with similar events during historical time, is a reminder that earthquakes of similar or larger magnitude pose a real hazard in eastern North America.

Success in transmitting hazard science

NASA Astrophysics Data System (ADS)

Price, J. G.; Garside, T.

2010-12-01

Money motivates mitigation. An example of success in communicating scientific information about hazards, coupled with information about available money, is the follow-up action by local governments to actually mitigate. The Nevada Hazard Mitigation Planning Committee helps local governments prepare competitive proposals for federal funds to reduce risks from natural hazards. Composed of volunteers with expertise in emergency management, building standards, and earthquake, flood, and wildfire hazards, the committee advises the Nevada Division of Emergency Management on (1) the content of the State’s hazard mitigation plan and (2) projects that have been proposed by local governments and state agencies for funding from various post- and pre-disaster hazard mitigation programs of the Federal Emergency Management Agency. Local governments must have FEMA-approved hazard mitigation plans in place before they can receive this funding. The committee has been meeting quarterly with elected and appointed county officials, at their offices, to encourage them to update their mitigation plans and apply for this funding. We have settled on a format that includes the county’s giving the committee an overview of its infrastructure, hazards, and preparedness. The committee explains the process for applying for mitigation grants and presents the latest information that we have about earthquake hazards, including locations of nearby active faults, historical seismicity, geodetic strain, loss-estimation modeling, scenarios, and documents about what to do before, during, and after an earthquake. Much of the county-specific information is available on the web. The presentations have been well received, in part because the committee makes the effort to go to their communities, and in part because the committee is helping them attract federal funds for local mitigation of not only earthquake hazards but also floods (including canal breaches) and wildfires, the other major concerns in

The 2012 Ferrara seismic sequence: Regional crustal structure, earthquake sources, and seismic hazard

NASA Astrophysics Data System (ADS)

Malagnini, Luca; Herrmann, Robert B.; Munafò, Irene; Buttinelli, Mauro; Anselmi, Mario; Akinci, Aybige; Boschi, E.

2012-10-01

Inadequate seismic design codes can be dangerous, particularly when they underestimate the true hazard. In this study we use data from a sequence of moderate-sized earthquakes in northeast Italy to validate and test a regional wave propagation model which, in turn, is used to understand some weaknesses of the current design spectra. Our velocity model, while regionalized and somewhat ad hoc, is consistent with geophysical observations and the local geology. In the 0.02-0.1 Hz band, this model is validated by using it to calculate moment tensor solutions of 20 earthquakes (5.6 ≥ MW ≥ 3.2) in the 2012 Ferrara, Italy, seismic sequence. The seismic spectra observed for the relatively small main shock significantly exceeded the design spectra to be used in the area for critical structures. Observations and synthetics reveal that the ground motions are dominated by long-duration surface waves, which, apparently, the design codes do not adequately anticipate. In light of our results, the present seismic hazard assessment in the entire Pianura Padana, including the city of Milan, needs to be re-evaluated.

The 2009 Samoa-Tonga great earthquake triggered doublet.

PubMed

Lay, Thorne; Ammon, Charles J; Kanamori, Hiroo; Rivera, Luis; Koper, Keith D; Hutko, Alexander R

2010-08-19

Great earthquakes (having seismic magnitudes of at least 8) usually involve abrupt sliding of rock masses at a boundary between tectonic plates. Such interplate ruptures produce dynamic and static stress changes that can activate nearby intraplate aftershocks, as is commonly observed in the trench-slope region seaward of a great subduction zone thrust event. The earthquake sequence addressed here involves a rare instance in which a great trench-slope intraplate earthquake triggered extensive interplate faulting, reversing the typical pattern and broadly expanding the seismic and tsunami hazard. On 29 September 2009, within two minutes of the initiation of a normal faulting event with moment magnitude 8.1 in the outer trench-slope at the northern end of the Tonga subduction zone, two major interplate underthrusting subevents (both with moment magnitude 7.8), with total moment equal to a second great earthquake of moment magnitude 8.0, ruptured the nearby subduction zone megathrust. The collective faulting produced tsunami waves with localized regions of about 12 metres run-up that claimed 192 lives in Samoa, American Samoa and Tonga. Overlap of the seismic signals obscured the fact that distinct faults separated by more than 50 km had ruptured with different geometries, with the triggered thrust faulting only being revealed by detailed seismic wave analyses. Extensive interplate and intraplate aftershock activity was activated over a large region of the northern Tonga subduction zone.

Regional liquefaction hazard evaluation following the 2010-2011 Christchurch (New Zealand) earthquake sequence

NASA Astrophysics Data System (ADS)

Begg, John; Brackley, Hannah; Irwin, Marion; Grant, Helen; Berryman, Kelvin; Dellow, Grant; Scott, David; Jones, Katie; Barrell, David; Lee, Julie; Townsend, Dougal; Jacka, Mike; Harwood, Nick; McCahon, Ian; Christensen, Steve

2013-04-01

Following the damaging 4 Sept 2010 Mw7.1 Darfield Earthquake, the 22 Feb 2011 Christchurch Earthquake and subsequent damaging aftershocks, we completed a liquefaction hazard evaluation for c. 2700 km2 of the coastal Canterbury region. Its purpose was to distinguish at a regional scale areas of land that, in the event of strong ground shaking, may be susceptible to damaging liquefaction from areas where damaging liquefaction is unlikely. This information will be used by local government for defining liquefaction-related geotechnical investigation requirements for consent applications. Following a review of historic records of liquefaction and existing liquefaction assessment maps, we undertook comprehensive new work that included: a geologic context from existing geologic maps; geomorphic mapping using LiDAR and integrating existing soil map data; compilation of lithological data for the surficial 10 m from an extensive drillhole database; modelling of depth to unconfined groundwater from existing subsurface and surface water data. Integrating and honouring all these sources of information, we mapped areas underlain by materials susceptible to liquefaction (liquefaction-prone lithologies present, or likely, in the near-surface, with shallow unconfined groundwater) from areas unlikely to suffer widespread liquefaction damage. Comparison of this work with more detailed liquefaction susceptibility assessment based on closely spaced geotechnical probes in Christchurch City provides a level of confidence in these results. We tested our susceptibility map by assigning a matrix of liquefaction susceptibility rankings to lithologies recorded in drillhole logs and local groundwater depths, then applying peak ground accelerations for four earthquake scenarios from the regional probabilistic seismic hazard model (25 year return = 0.13g; 100 year return = 0.22g; 500 year return = 0.38g and 2500 year return = 0.6g). Our mapped boundary between liquefaction-prone areas and areas

New seafloor map of the Puerto Rico trench helps assess earthquake and tsunami hazards

NASA Astrophysics Data System (ADS)

Brink, Uri ten; Danforth, William; Polloni, Christopher; Andrews, Brian; Llanes, Pilar; Smith, Shepard; Parker, Eugene; Uozumi, Toshihiko

2004-09-01

The Puerto Rico Trench, the deepest part of the Atlantic Ocean, is located where the North American (NOAM) plate is subducting under the Caribbean plate (Figure l). The trench region may pose significant seismic and tsunami hazards to Puerto Rico and the U.S.Virgin Islands, where 4 million U.S. citizens reside. Widespread damage in Puerto Rico and Hispaniola from an earthquake in 1787 was estimated to be the result of a magnitude 8 earthquake north of the islands [McCann et al., 2004]. A tsunami killed 40 people in NW Puerto Rico following a magnitude 7.3 earthquake in 1918 [Mercado and McCann, 1998]. Large landslide escarpments have been mapped on the seafloor north of Puerto Rico [Mercado et al., 2002; Schwab et al., 1991],although their ages are unknown.

New seafloor map of the Puerto Rico Trench helps assess earthquake and tsunami hazards

USGS Publications Warehouse

ten Brink, Uri S.; Danforth, William; Polloni, Christopher; Andrews, Brian D.; Llanes Estrada, Pilar; Smith, Shepard; Parker, Eugene; Uozumi, Toshihiko

2004-01-01

The Puerto Rico Trench, the deepest part of the Atlantic Ocean, is located where the North American (NOAM) plate is subducting under the Caribbean plate (Figure l). The trench region may pose significant seismic and tsunami hazards to Puerto Rico and the U.S.Virgin Islands, where 4 million U.S. citizens reside. Widespread damage in Puerto Rico and Hispaniola from an earthquake in 1787 was estimated to be the result of a magnitude 8 earthquake north of the islands [McCann et al., 2004]. A tsunami killed 40 people in NW Puerto Rico following a magnitude 7.3 earthquake in 1918 [Mercado and McCann, 1998]. Large landslide escarpments have been mapped on the seafloor north of Puerto Rico [Mercado et al., 2002; Schwab et al., 1991],although their ages are unknown.

Earthquake Advisory Services: A prototype development project

NASA Astrophysics Data System (ADS)

Lagorio, H. J.; Levin, H.

1980-10-01

Development of the prototype Earthquake Advisory Service (EAS) is reported. The EAS is designed to provide direct technical assistance and written materials to advise people who wish to make informed decisions about earthquake hazard reduction in their residences. It is intended also to be adapted to local conditions by community-based agencies. The EAS prototype involved the testing of early assumptions about program implementation, establishment of a systematic methodology review process, and a review of published information pertinent to the project. Operational procedures of the program and the process leading to implementation guidelines are described.

Citizen Seismology Provides Insights into Ground Motions and Hazard from Injection-Induced Earthquakes

NASA Astrophysics Data System (ADS)

Hough, S. E.

2014-12-01

The US Geological Survey "Did You Feel It?" (DYFI) system is a highly successful example of citizen seismology. Users around the world now routinely report felt earthquakes via the Web; this information is used to determine Community Decimal Intensity values. These data can be enormously valuable for helping address a key issue that has arisen recently: quantifying the shaking/hazard associated with injection-induced earthquakes. I consider the shaking from 11 moderate (Mw3.9-5.7) earthquakes in the central and eastern United States that are believed to be induced by fluid injection. The distance decay of intensities for all events is consistent with that observed for regional tectonic earthquakes, but for all of the events intensities are lower than values predicted from an intensity prediction equation derived using data from tectonic events. I introduce an effective intensity magnitude, MIE, defined as the magnitude that on average would generate a given intensity distribution. For all 11 events, MIE is lower than the event magnitude by 0.4-1.3 units, with an average difference of 0.8 units. This suggests that stress drops of injection-induced earthquakes are lower than tectonic earthquakes by a factor of 2-10. However, relatively limited data suggest that intensities for epicentral distances less than 10 km are more commensurate with expectations for the event magnitude, which can be explained by the shallow focal depth of the events. The results suggest that damage from injection-induced earthquakes will be especially concentrated in the immediate epicentral region. These results further suggest a potential new discriminant for the identification of induced events. For ecample, while systematic analysis of California earthquakes remains to be done, DYFI data from the 2014 Mw5.1 La Habra, California, earthquake reveal no evidence for unusually low intensities, adding to a growing volume of evidence that this was a natural tectonic event.

California Fault Parameters for the National Seismic Hazard Maps and Working Group on California Earthquake Probabilities 2007

USGS Publications Warehouse

Wills, Chris J.; Weldon, Ray J.; Bryant, W.A.

2008-01-01

This report describes development of fault parameters for the 2007 update of the National Seismic Hazard Maps and the Working Group on California Earthquake Probabilities (WGCEP, 2007). These reference parameters are contained within a database intended to be a source of values for use by scientists interested in producing either seismic hazard or deformation models to better understand the current seismic hazards in California. These parameters include descriptions of the geometry and rates of movements of faults throughout the state. These values are intended to provide a starting point for development of more sophisticated deformation models which include known rates of movement on faults as well as geodetic measurements of crustal movement and the rates of movements of the tectonic plates. The values will be used in developing the next generation of the time-independent National Seismic Hazard Maps, and the time-dependant seismic hazard calculations being developed for the WGCEP. Due to the multiple uses of this information, development of these parameters has been coordinated between USGS, CGS and SCEC. SCEC provided the database development and editing tools, in consultation with USGS, Golden. This database has been implemented in Oracle and supports electronic access (e.g., for on-the-fly access). A GUI-based application has also been developed to aid in populating the database. Both the continually updated 'living' version of this database, as well as any locked-down official releases (e.g., used in a published model for calculating earthquake probabilities or seismic shaking hazards) are part of the USGS Quaternary Fault and Fold Database http://earthquake.usgs.gov/regional/qfaults/ . CGS has been primarily responsible for updating and editing of the fault parameters, with extensive input from USGS and SCEC scientists.

Kinematics, mechanics, and potential earthquake hazards for faults in Pottawatomie County, Kansas, USA

USGS Publications Warehouse

Ohlmacher, G.C.; Berendsen, P.

2005-01-01

Many stable continental regions have subregions with poorly defined earthquake hazards. Analysis of minor structures (folds and faults) in these subregions can improve our understanding of the tectonics and earthquake hazards. Detailed structural mapping in Pottawatomie County has revealed a suite consisting of two uplifted blocks aligned along a northeast trend and surrounded by faults. The first uplift is located southwest of the second. The northwest and southeast sides of these uplifts are bounded by northeast-trending right-lateral faults. To the east, both uplifts are bounded by north-trending reverse faults, and the first uplift is bounded by a north-trending high-angle fault to the west. The structural suite occurs above a basement fault that is part of a series of north-northeast-trending faults that delineate the Humboldt Fault Zone of eastern Kansas, an integral part of the Midcontinent Rift System. The favored kinematic model is a contractional stepover (push-up) between echelon strike-slip faults. Mechanical modeling using the boundary element method supports the interpretation of the uplifts as contractional stepovers and indicates that an approximately east-northeast maximum compressive stress trajectory is responsible for the formation of the structural suite. This stress trajectory suggests potential activity during the Laramide Orogeny, which agrees with the age of kimberlite emplacement in adjacent Riley County. The current stress field in Kansas has a N85??W maximum compressive stress trajectory that could potentially produce earthquakes along the basement faults. Several epicenters of seismic events (

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

NASA Astrophysics Data System (ADS)

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

Introduction: seismology and earthquake engineering in Mexico and Central and South America.

USGS Publications Warehouse

Espinosa, A.F.

1982-01-01

The results from seismological studies that are used by the engineering community are just one of the benefits obtained from research aimed at mitigating the earthquake hazard. In this issue of Earthquake Information Bulletin current programs in seismology and earthquake engineering, seismic networks, future plans and some of the cooperative programs with different internation organizations are described by Latin-American seismologists. The article describes the development of seismology in Latin America and the seismological interest of the OAS. -P.N.Chroston

Subduction zone and crustal dynamics of western Washington; a tectonic model for earthquake hazards evaluation

USGS Publications Warehouse

Stanley, Dal; Villaseñor, Antonio; Benz, Harley

1999-01-01

The Cascadia subduction zone is extremely complex in the western Washington region, involving local deformation of the subducting Juan de Fuca plate and complicated block structures in the crust. It has been postulated that the Cascadia subduction zone could be the source for a large thrust earthquake, possibly as large as M9.0. Large intraplate earthquakes from within the subducting Juan de Fuca plate beneath the Puget Sound region have accounted for most of the energy release in this century and future such large earthquakes are expected. Added to these possible hazards is clear evidence for strong crustal deformation events in the Puget Sound region near faults such as the Seattle fault, which passes through the southern Seattle metropolitan area. In order to understand the nature of these individual earthquake sources and their possible interrelationship, we have conducted an extensive seismotectonic study of the region. We have employed P-wave velocity models developed using local earthquake tomography as a key tool in this research. Other information utilized includes geological, paleoseismic, gravity, magnetic, magnetotelluric, deformation, seismicity, focal mechanism and geodetic data. Neotectonic concepts were tested and augmented through use of anelastic (creep) deformation models based on thin-plate, finite-element techniques developed by Peter Bird, UCLA. These programs model anelastic strain rate, stress, and velocity fields for given rheological parameters, variable crust and lithosphere thicknesses, heat flow, and elevation. Known faults in western Washington and the main Cascadia subduction thrust were incorporated in the modeling process. Significant results from the velocity models include delineation of a previously studied arch in the subducting Juan de Fuca plate. The axis of the arch is oriented in the direction of current subduction and asymmetrically deformed due to the effects of a northern buttress mapped in the velocity models. This

Earthquake Emergency Education in Dushanbe, Tajikistan

ERIC Educational Resources Information Center

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…

Probabilistic seismic hazard assessments of Sabah, east Malaysia: accounting for local earthquake activity near Ranau

NASA Astrophysics Data System (ADS)

Khalil, Amin E.; Abir, Ismail A.; Ginsos, Hanteh; Abdel Hafiez, Hesham E.; Khan, Sohail

2018-02-01

Sabah state in eastern Malaysia, unlike most of the other Malaysian states, is characterized by common seismological activity; generally an earthquake of moderate magnitude is experienced at an interval of roughly every 20 years, originating mainly from two major sources, either a local source (e.g. Ranau and Lahad Dato) or a regional source (e.g. Kalimantan and South Philippines subductions). The seismicity map of Sabah shows the presence of two zones of distinctive seismicity, these zones are near Ranau (near Kota Kinabalu) and Lahad Datu in the southeast of Sabah. The seismicity record of Ranau begins in 1991, according to the international seismicity bulletins (e.g. United States Geological Survey and the International Seismological Center), and this short record is not sufficient for seismic source characterization. Fortunately, active Quaternary fault systems are delineated in the area. Henceforth, the seismicity of the area is thus determined as line sources referring to these faults. Two main fault systems are believed to be the source of such activities; namely, the Mensaban fault zone and the Crocker fault zone in addition to some other faults in their vicinity. Seismic hazard assessments became a very important and needed study for the extensive developing projects in Sabah especially with the presence of earthquake activities. Probabilistic seismic hazard assessments are adopted for the present work since it can provide the probability of various ground motion levels during expected from future large earthquakes. The output results are presented in terms of spectral acceleration curves and uniform hazard curves for periods of 500, 1000 and 2500 years. Since this is the first time that a complete hazard study has been done for the area, the output will be a base and standard for any future strategic plans in the area.

Teamwork tools and activities within the hazard component of the Global Earthquake Model

NASA Astrophysics Data System (ADS)

Pagani, M.; Weatherill, G.; Monelli, D.; Danciu, L.

2013-05-01

The Global Earthquake Model (GEM) is a public-private partnership aimed at supporting and fostering a global community of scientists and engineers working in the fields of seismic hazard and risk assessment. In the hazard sector, in particular, GEM recognizes the importance of local ownership and leadership in the creation of seismic hazard models. For this reason, over the last few years, GEM has been promoting different activities in the context of seismic hazard analysis ranging, for example, from regional projects targeted at the creation of updated seismic hazard studies to the development of a new open-source seismic hazard and risk calculation software called OpenQuake-engine (http://globalquakemodel.org). In this communication we'll provide a tour of the various activities completed, such as the new ISC-GEM Global Instrumental Catalogue, and of currently on-going initiatives like the creation of a suite of tools for the creation of PSHA input models. Discussion, comments and criticism by the colleagues in the audience will be highly appreciated.

Seismic hazard evaluation of the Oman India pipeline

DOE Office of Scientific and Technical Information (OSTI.GOV)

Campbell, K.W.; Thenhaus, P.C.; Mullee, J.E.

1996-12-31

The proposed Oman India pipeline will traverse approximately 1,135 km of the northern Arabian Sea floor and adjacent continental shelves at depths of over 3 km on its route from Ra`s al Jifan, Oman, to Rapar Gadhwali, India. The western part of the route crosses active faults that form the transform boundary between the Arabian and Indian tectonic plates. The eastern terminus of the route lies in the vicinity of the great (M {approximately} 8) 1829 Kutch, India earthquake. A probabilistic seismic hazard analysis was used to estimate the values of peak ground acceleration (PGA) with return periods of 200,more » 500 and 1,000 years at selected locations along the pipeline route and the submarine Indus Canyon -- a possible source of large turbidity flows. The results defined the ground-shaking hazard along the pipeline route and Indus Canyon for evaluation of risks to the pipeline from potential earthquake-induced geologic hazards such as liquefaction, slope instability, and turbidity flows. 44 refs.« less

Update of the USGS 2016 One-year Seismic Hazard Forecast for the Central and Eastern United States From Induced and Natural Earthquakes

NASA Astrophysics Data System (ADS)

Petersen, M. D.; Mueller, C. S.; Moschetti, M. P.; Hoover, S. M.; Llenos, A. L.; Ellsworth, W. L.; Michael, A. J.; Rubinstein, J. L.; McGarr, A.; Rukstales, K. S.

2016-12-01

The U.S. Geological Survey released a 2016 one-year forecast for seismic hazard in the central and eastern U.S., which included the influence from both induced and natural earthquakes. This forecast was primarily based on 2015 declustered seismicity rates but also included longer-term rates, 10- and 20- km smoothing distances, earthquakes between Mw 4.7 and maximum magnitudes of 6.0 or 7.1, and 9 alternative ground motion models. Results indicate that areas in Oklahoma, Kansas, Colorado, New Mexico, Arkansas, Texas, and the New Madrid Seismic Zone have a significant chance for damaging ground shaking levels in 2016 (greater than 1% chance of exceeding 0.12 PGA and MMI VI). We evaluate this one-year forecast by considering the earthquakes and ground shaking levels that occurred during the first half of 2016 (earthquakes not included in the forecast). During this period the full catalog records hundreds of events with M ≥ 3.0, but the declustered catalog eliminates most of these dependent earthquakes and results in much lower numbers of earthquakes. The declustered catalog based on USGS COMCAT indicates a M 5.1 earthquake occurred in the zone of highest hazard on the map. Two additional earthquakes of M ≥ 4.0 occurred in Oklahoma, and about 82 earthquakes of M ≥ 3.0 occurred with 77 in Oklahoma and Kansas, 4 in Raton Basin Colorado/New Mexico, and 1 near Cogdell Texas. In addition, 72 earthquakes occurred outside the zones of induced seismicity with more than half in New Madrid and eastern Tennessee. The catalog rates in the first half of 2016 and the corresponding seismic hazard were generally lower than in 2015. For example, the zones for Irving, Venus, and Fashing, Texas; Sun City, Kansas; and north-central Arkansas did not experience any earthquakes with M≥ 2.7 during this period. The full catalog rates were lower by about 30% in Raton Basin and the Oklahoma-Kansas zones but the declustered catalog rates did not drop as much. This decrease in earthquake

Summary of November 2010 meeting to evaluate turbidite data for constraining the recurrence parameters of great Cascadia earthquakes for the update of national seismic hazard maps

USGS Publications Warehouse

Frankel, Arthur D.

2011-01-01

earthquakes over the past 5,000 years. The instrumental catalog of earthquakes is of little use for constraining the hazard of the CSZ, because there are virtually no recorded earthquakes on most of the plate interface of the CSZ. There are no historical accounts in the past 150 years of large earthquakes on most of the CSZ. Until about 20 years ago, some interpreted this lack of recent and historical earthquakes as an indicator that the subduction zone was slipping aseismically and could not produce a great earthquake. The work of Brian Atwater and others, in the late 1980s and the 1990s (Atwater, 1987, 1992; Atwater and others, 1995; Nelson and others, 1996; Clague, 1997; Atwater and Hemphill-Haley, 1997; Atwater and others, 2004) demonstrated that submerged forests, buried soils, tsunami deposits, and liquefaction along and near the coast were compelling evidence of repeated great Cascadia earthquakes over at least the past 5,000 years. Atwater and Hemphill-Haley (1997) concluded from paleoseismic evidence at Willapa Bay, Washington, that great earthquakes ruptured the CSZ with an average recurrence time of about 500 years. The date of the last great CSZ earthquake, January 26, 1700, was established from historical records of the so-called orphan tsunami in Japan that is inferred to have been produced by this earthquake (Satake and others, 1996, 2003; Atwater and others, 2005) and is consistent with tree-ring data from drowned forests in Washington and Oregon. From modeling the observations of the tsunami, Satake and others (2003) estimated a moment magnitude of about 9.0 for this earthquake. Many other paleoseismic sites have been investigated along the Pacific Northwest coast from Vancouver Island to northern California and show evidence of great CSZ earthquakes. Nelson and others (2006) summarized the dates found from these studies and proposed correlations between sites indicating the extent of rupture for individual events. Dating of inferred tsunami deposits in

Seismic hazard along a crude oil pipeline in the event of an 1811-1812 type New Madrid earthquake. Technical report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hwang, H.H.M.; Chen, C.H.S.

1990-04-16

An assessment of the seismic hazard that exists along the major crude oil pipeline running through the New Madrid seismic zone from southeastern Louisiana to Patoka, Illinois is examined in the report. An 1811-1812 type New Madrid earthquake with moment magnitude 8.2 is assumed to occur at three locations where large historical earthquakes have occurred. Six pipeline crossings of the major rivers in West Tennessee are chosen as the sites for hazard evaluation because of the liquefaction potential at these sites. A seismologically-based model is used to predict the bedrock accelerations. Uncertainties in three model parameters, i.e., stress parameter, cutoffmore » frequency, and strong-motion duration are included in the analysis. Each parameter is represented by three typical values. From the combination of these typical values, a total of 27 earthquake time histories can be generated for each selected site due to an 1811-1812 type New Madrid earthquake occurring at a postulated seismic source.« less

Satellite Geodetic Constraints On Earthquake Processes: Implications of the 1999 Turkish Earthquakes for Fault Mechanics and Seismic Hazards on the San Andreas Fault

NASA Technical Reports Server (NTRS)

Reilinger, Robert

2005-01-01

Our principal activities during the initial phase of this project include: 1) Continued monitoring of postseismic deformation for the 1999 Izmit and Duzce, Turkey earthquakes from repeated GPS survey measurements and expansion of the Marmara Continuous GPS Network (MAGNET), 2) Establishing three North Anatolian fault crossing profiles (10 sitedprofile) at locations that experienced major surface-fault earthquakes at different times in the past to examine strain accumulation as a function of time in the earthquake cycle (2004), 3) Repeat observations of selected sites in the fault-crossing profiles (2005), 4) Repeat surveys of the Marmara GPS network to continue to monitor postseismic deformation, 5) Refining block models for the Marmara Sea seismic gap area to better understand earthquake hazards in the Greater Istanbul area, 6) Continuing development of models for afterslip and distributed viscoelastic deformation for the earthquake cycle. We are keeping close contact with MIT colleagues (Brad Hager, and Eric Hetland) who are developing models for S. California and for the earthquake cycle in general (Hetland, 2006). In addition, our Turkish partners at the Marmara Research Center have undertaken repeat, micro-gravity measurements at the MAGNET sites and have provided us estimates of gravity change during the period 2003 - 2005.

Earthquakes and depleted gas reservoirs: which comes first?

NASA Astrophysics Data System (ADS)

Mucciarelli, M.; Donda, F.; Valensise, G.

2015-10-01

While scientists are paying increasing attention to the seismicity potentially induced by hydrocarbon exploitation, so far, little is known about the reverse problem, i.e. the impact of active faulting and earthquakes on hydrocarbon reservoirs. The 20 and 29 May 2012 earthquakes in Emilia, northern Italy (Mw 6.1 and 6.0), raised concerns among the public for being possibly human-induced, but also shed light on the possible use of gas wells as a marker of the seismogenic potential of an active fold and thrust belt. We compared the location, depth and production history of 455 gas wells drilled along the Ferrara-Romagna arc, a large hydrocarbon reserve in the southeastern Po Plain (northern Italy), with the location of the inferred surface projection of the causative faults of the 2012 Emilia earthquakes and of two pre-instrumental damaging earthquakes. We found that these earthquake sources fall within a cluster of sterile wells, surrounded by productive wells at a few kilometres' distance. Since the geology of the productive and sterile areas is quite similar, we suggest that past earthquakes caused the loss of all natural gas from the potential reservoirs lying above their causative faults. To validate our hypothesis we performed two different statistical tests (binomial and Monte Carlo) on the relative distribution of productive and sterile wells, with respect to seismogenic faults. Our findings have important practical implications: (1) they may allow major seismogenic sources to be singled out within large active thrust systems; (2) they suggest that reservoirs hosted in smaller anticlines are more likely to be intact; and (3) they also suggest that in order to minimize the hazard of triggering significant earthquakes, all new gas storage facilities should use exploited reservoirs rather than sterile hydrocarbon traps or aquifers.

Volcano Hazards Program

USGS Publications Warehouse

Venezky, Dina Y.; Myers, Bobbie; Driedger, Carolyn

2008-01-01

Diagram of common volcano hazards. The U.S. Geological Survey Volcano Hazards Program (VHP) monitors unrest and eruptions at U.S. volcanoes, assesses potential hazards, responds to volcanic crises, and conducts research on how volcanoes work. When conditions change at a monitored volcano, the VHP issues public advisories and warnings to alert emergency-management authorities and the public. See http://volcanoes.usgs.gov/ to learn more about volcanoes and find out what's happening now.

7th U.S. / Japan Natural Resources (UJNR) Panel on Earthquake Research: Abstract Volume and Technical Program

USGS Publications Warehouse

Detweiler, Shane T.; Ellsworth, William L.

2008-01-01

The U.S. / Japan Natural Resources (UJNR) Panel on Earthquake Research promotes advanced study toward a more fundamental understanding of the earthquake process and hazard estimation. The Panel promotes basic and applied research to improve our understanding of the causes and effects of earthquakes and to facilitate the transmission of research results to those who implement hazard reduction measures on both sides of the Pacific and around the world. Meetings are held every other year, and alternate between countries with short presentation on current research and local field trips being the highlights. The 5th Joint Panel meeting was held at Asilomar, California in October, 2004. The technical sessions featured reports on the September 28, 2004 Parkfield, California earthquake, progress on earthquake early warning and rapid post-event assessment technology, probabilistic earthquake forecasting and the newly discovered phenomenon of nonvolcanic tremor. The Panel visited the epicentral region of the M 6.0 Parkfield earthquake and viewed the surface ruptures along the San Andreas Fault. They also visited the San Andreas Fault Observatory at Depth (SAFOD), which had just completed the first phase of drilling into the fault. The 6th Joint Panel meeting was held in Tokushima, Japan in November, 2006. The meeting included very productive exchanges of information on approaches to systematic observation of earthquake processes. Sixty eight technical papers were presented during the meeting on a wide range of subjects, including interplate earthquakes in subduction zones, slow slip and nonvolcanic tremor, crustal deformation, recent earthquake activity and hazard mapping. Through our discussion, we reaffirmed the benefits of working together to achieve our common goal of reducing earthquake hazard, continued cooperation on issues involving densification of observation networks and the open exchange of data among scientific communities. We also reaffirmed the importance of

Shallow slip amplification and enhanced tsunami hazard unravelled by dynamic simulations of mega-thrust earthquakes

PubMed Central

Murphy, S.; Scala, A.; Herrero, A.; Lorito, S.; Festa, G.; Trasatti, E.; Tonini, R.; Romano, F.; Molinari, I.; Nielsen, S.

2016-01-01

The 2011 Tohoku earthquake produced an unexpected large amount of shallow slip greatly contributing to the ensuing tsunami. How frequent are such events? How can they be efficiently modelled for tsunami hazard? Stochastic slip models, which can be computed rapidly, are used to explore the natural slip variability; however, they generally do not deal specifically with shallow slip features. We study the systematic depth-dependence of slip along a thrust fault with a number of 2D dynamic simulations using stochastic shear stress distributions and a geometry based on the cross section of the Tohoku fault. We obtain a probability density for the slip distribution, which varies both with depth, earthquake size and whether the rupture breaks the surface. We propose a method to modify stochastic slip distributions according to this dynamically-derived probability distribution. This method may be efficiently applied to produce large numbers of heterogeneous slip distributions for probabilistic tsunami hazard analysis. Using numerous M9 earthquake scenarios, we demonstrate that incorporating the dynamically-derived probability distribution does enhance the conditional probability of exceedance of maximum estimated tsunami wave heights along the Japanese coast. This technique for integrating dynamic features in stochastic models can be extended to any subduction zone and faulting style. PMID:27725733

Integrating Caribbean Seismic and Tsunami Hazard into Public Policy and Action

NASA Astrophysics Data System (ADS)

von Hillebrandt-Andrade, C.

2012-12-01

The Caribbean has a long history of tsunamis and earthquakes. Over the past 500 years, more than 80 tsunamis have been documented in the region by the NOAA National Geophysical Data Center. Almost 90% of all these historical tsunamis have been associated with earthquakes. Just since 1842, 3510 lives have been lost to tsunamis; this is more than in the Northeastern Pacific for the same time period. With a population of almost 160 million and a heavy concentration of residents, tourists, businesses and critical infrastructure along the Caribbean shores (especially in the northern and eastern Caribbean), the risk to lives and livelihoods is greater than ever before. Most of the countries also have a very high exposure to earthquakes. Given the elevated vulnerability, it is imperative that government officials take steps to mitigate the potentially devastating effects of these events. Nevertheless, given the low frequency of high impact earthquakes and tsunamis, in comparison to hurricanes, combined with social and economic considerations, the needed investments are not made and disasters like the 2010 Haiti earthquake occur. In the absence of frequent significant events, an important driving force for public officials to take action, is the dissemination of scientific studies. When papers of this nature have been published and media advisories issued, public officials demonstrate heightened interest in the topic which in turn can lead to increased legislation and funding efforts. This is especially the case if the material can be easily understood by the stakeholders and there is a local contact. In addition, given the close link between earthquakes and tsunamis, in Puerto Rico alone, 50% of the high impact earthquakes have also generated destructive tsunamis, it is very important that earthquake and tsunami hazards studies demonstrate consistency. Traditionally in the region, earthquake and tsunami impacts have been considered independently in the emergency planning

Earthquake information products and tools from the Advanced National Seismic System (ANSS)

USGS Publications Warehouse

Wald, Lisa

2006-01-01

This Fact Sheet provides a brief description of postearthquake tools and products provided by the Advanced National Seismic System (ANSS) through the U.S. Geological Survey Earthquake Hazards Program. The focus is on products specifically aimed at providing situational awareness in the period immediately following significant earthquake events.

7 CFR 4280.36 - Other laws that contain compliance requirements for these Programs.

Code of Federal Regulations, 2010 CFR

2010-01-01

... U.S.C. 1352, and 7 CFR part 3018, are applicable to these Programs. (j) Earthquake hazards. These Programs are subject to the seismic requirements of the Earthquake Hazards Reduction Act of 1977 (42 U.S.C...

7 CFR 4280.36 - Other laws that contain compliance requirements for these Programs.

Code of Federal Regulations, 2013 CFR

2013-01-01

... U.S.C. 1352, and 7 CFR part 3018, are applicable to these Programs. (j) Earthquake hazards. These Programs are subject to the seismic requirements of the Earthquake Hazards Reduction Act of 1977 (42 U.S.C...

7 CFR 4280.36 - Other laws that contain compliance requirements for these Programs.

Code of Federal Regulations, 2012 CFR

2012-01-01

... U.S.C. 1352, and 7 CFR part 3018, are applicable to these Programs. (j) Earthquake hazards. These Programs are subject to the seismic requirements of the Earthquake Hazards Reduction Act of 1977 (42 U.S.C...

7 CFR 4280.36 - Other laws that contain compliance requirements for these Programs.

Code of Federal Regulations, 2014 CFR

2014-01-01

... U.S.C. 1352, and 7 CFR part 3018, are applicable to these Programs. (j) Earthquake hazards. These Programs are subject to the seismic requirements of the Earthquake Hazards Reduction Act of 1977 (42 U.S.C...

7 CFR 4280.36 - Other laws that contain compliance requirements for these Programs.

Code of Federal Regulations, 2011 CFR

2011-01-01

... U.S.C. 1352, and 7 CFR part 3018, are applicable to these Programs. (j) Earthquake hazards. These Programs are subject to the seismic requirements of the Earthquake Hazards Reduction Act of 1977 (42 U.S.C...

Aftershock source properties of events following the 2013 Craig Earthquake: new evidence for structural heterogeneity on the northern Queen Charlotte Fault

NASA Astrophysics Data System (ADS)

Roland, E. C.; Walton, M. A. L.; Ruppert, N. A.; Gulick, S. P. S.; Christeson, G. L.; Haeussler, P. J.

2014-12-01

In January 2013, a Mw 7.5 earthquake ruptured a segment of the Queen Charlotte Fault offshore the town of Craig in southeast Alaska. The region of the fault that slipped during the Craig earthquake is adjacent to and possibly overlapping with the northern extent of the 1949 M 8.1 Queen Charlotte earthquake rupture (Canada's largest recorded earthquake), and is just south of the rupture area of the 1972 M 7.6 earthquake near Sitka, Alaska. Here we present aftershock locations and focal mechanisms for events that occurred four months following the mainshock using data recorded on an Ocean Bottom Seismometer (OBS) array that was deployed offshore of Prince of Wales Island. This array consisted of 9 short period instruments surrounding the fault segment, and recorded hundreds of aftershocks during the months of April and May, 2013. In addition to highlighting the primary mainshock rupture plane, aftershocks also appear to be occurring along secondary fault structures adjacent to the main fault trace, illuminating complicated structure, particularly toward the northern extent of the Craig rupture. Focal mechanisms for the larger events recorded during the OBS deployment show both near-vertical strike slip motion consistent with the mainshock mechanism, as well as events with varying strike and a component of normal faulting. Although fault structure along this northern segment of the QCF appears to be considerably simpler than to the south, where a higher degree of oblique convergence leads to sub-parallel compressional deformation structures, secondary faulting structures apparent in legacy seismic reflection data near the Craig rupture may be consistent with the observed seismicity patterns. In combination, these data may help to characterize structural heterogeneity along the northern segment of the Queen Charlotte Fault that contributes to rupture segmentation during large strike slip events.

Simulation of tsunamis from great earthquakes on the cascadia subduction zone.

PubMed

Ng, M K; Leblond, P H; Murty, T S

1990-11-30

Large earthquakes occur episodically in the Cascadia subduction zone. A numerical model has been used to simulate and assess the hazards of a tsunami generated by a hypothetical earthquake of magnitude 8.5 associated with rupture of the northern sections of the subduction zone. Wave amplitudes on the outer coast are closely related to the magnitude of sea-bottom displacement (5.0 meters). Some amplification, up to a factor of 3, may occur in some coastal embayments. Wave amplitudes in the protected waters of Puget Sound and the Strait of Georgia are predicted to be only about one fifth of those estmated on the outer coast.

Special Issue "Impact of Natural Hazards on Urban Areas and Infrastructure" in the Bulletin of Earthquake Engineering

NASA Astrophysics Data System (ADS)

Bostenaru Dan, M.

2009-04-01

This special issue includes selected papers on the topic of earthquake impact from the sessions held in 2004 in Nice, France and in 2005 in Vienna, Austria at the first and respectivelly the second European Geosciences Union General Assembly. Since its start in 1999, in the Hague, Netherlands, the hazard of earthquakes has been the most popular of the session. The respective calls in 2004 was for: Nature's forces including earthquakes, floods, landslides, high winds and volcanic eruptions can inflict losses to urban settlements and man-made structures such as infrastructure. In Europe, recent years have seen such significant losses from earthquakes in south and south-eastern Europe, floods in central Europe, and wind storms in western Europe. Meanwhile, significant progress has been made in understanding disasters. Several scientific fields contribute to a holistic approach in the evaluation of capacities, vulnerabilities and hazards, the main factors on mitigating urban disasters due to natural hazards. An important part of the session is devoted to assessment of earthquake shaking and loss scenarios, including both physical damage and human causalities. Early warning and rapid damage evaluation are of utmost importance for addressing the safety of many essential facilities, for emergency management of events and for disaster response. In case of earthquake occurrence strong motion networks, data processing and interpretation lead to preliminary estimation (scenarios) of geographical distribution of damages. Factual information on inflicted damage, like those obtained from shaking maps or aerial imagery permit a confrontation with simulation maps of damage in order to define a more accurate picture of the overall losses. Most recent developments towards quantitative and qualitative simulation of natural hazard impacts on urban areas, which provide decision-making support for urban disaster management, and success stories of and lessons learned from disaster

Probabilistic Tsunami Hazard Assessment along Nankai Trough (2) a comprehensive assessment including a variety of earthquake source areas other than those that the Earthquake Research Committee, Japanese government (2013) showed

NASA Astrophysics Data System (ADS)

Hirata, K.; Fujiwara, H.; Nakamura, H.; Osada, M.; Morikawa, N.; Kawai, S.; Ohsumi, T.; Aoi, S.; Yamamoto, N.; Matsuyama, H.; Toyama, N.; Kito, T.; Murashima, Y.; Murata, Y.; Inoue, T.; Saito, R.; Takayama, J.; Akiyama, S.; Korenaga, M.; Abe, Y.; Hashimoto, N.

2016-12-01

For the forthcoming Nankai earthquake with M8 to M9 class, the Earthquake Research Committee(ERC)/Headquarters for Earthquake Research Promotion, Japanese government (2013) showed 15 examples of earthquake source areas (ESAs) as possible combinations of 18 sub-regions (6 segments along trough and 3 segments normal to trough) and assessed the occurrence probability within the next 30 years (from Jan. 1, 2013) was 60% to 70%. Hirata et al.(2015, AGU) presented Probabilistic Tsunami Hazard Assessment (PTHA) along Nankai Trough in the case where diversity of the next event's ESA is modeled by only the 15 ESAs. In this study, we newly set 70 ESAs in addition of the previous 15 ESAs so that total of 85 ESAs are considered. By producing tens of faults models, with various slip distribution patterns, for each of 85 ESAs, we obtain 2500 fault models in addition of previous 1400 fault models so that total of 3900 fault models are considered to model the diversity of the next Nankai earthquake rupture (Toyama et al.,2015, JpGU). For PTHA, the occurrence probability of the next Nankai earthquake is distributed to possible 3900 fault models in the viewpoint of similarity to the 15 ESAs' extents (Abe et al.,2015, JpGU). A major concept of the occurrence probability distribution is; (i) earthquakes rupturing on any of 15 ESAs that ERC(2013) showed most likely occur, (ii) earthquakes rupturing on any of ESAs whose along-trench extent is the same as any of 15 ESAs but trough-normal extent differs from it second likely occur, (iii) earthquakes rupturing on any of ESAs whose both of along-trough and trough-normal extents differ from any of 15 ESAs rarely occur. Procedures for tsunami simulation and probabilistic tsunami hazard synthesis are the same as Hirata et al (2015). A tsunami hazard map, synthesized under an assumption that the Nankai earthquakes can be modeled as a renewal process based on BPT distribution with a mean recurrence interval of 88.2 years (ERC, 2013) and an

Earthquake catalog for estimation of maximum earthquake magnitude, Central and Eastern United States: Part B, historical earthquakes

USGS Publications Warehouse

Wheeler, Russell L.

2014-01-01

Computation of probabilistic earthquake hazard requires an estimate of Mmax: the moment magnitude of the largest earthquake that is thought to be possible within a specified geographic region. The region specified in this report is the Central and Eastern United States and adjacent Canada. Parts A and B of this report describe the construction of a global catalog of moderate to large earthquakes that occurred worldwide in tectonic analogs of the Central and Eastern United States. Examination of histograms of the magnitudes of these earthquakes allows estimation of Central and Eastern United States Mmax. The catalog and Mmax estimates derived from it are used in the 2014 edition of the U.S. Geological Survey national seismic-hazard maps. Part A deals with prehistoric earthquakes, and this part deals with historical events.

The 1945 Balochistan earthquake and probabilistic tsunami hazard assessment for the Makran subduction zone

NASA Astrophysics Data System (ADS)

Höchner, Andreas; Babeyko, Andrey; Zamora, Natalia

2014-05-01

Iran and Pakistan are countries quite frequently affected by destructive earthquakes. For instance, the magnitude 6.6 Bam earthquake in 2003 in Iran with about 30'000 casualties, or the magnitude 7.6 Kashmir earthquake 2005 in Pakistan with about 80'000 casualties. Both events took place inland, but in terms of magnitude, even significantly larger events can be expected to happen offshore, at the Makran subduction zone. This small subduction zone is seismically rather quiescent, but a tsunami caused by a thrust event in 1945 (Balochistan earthquake) led to about 4000 casualties. Nowadays, the coastal regions are more densely populated and vulnerable to similar events. Additionally, some recent publications raise the question of the possiblity of rare but huge magnitude 9 events at the Makran subduction zone. We first model the historic Balochistan event and its effect in terms of coastal wave heights, and then generate various synthetic earthquake and tsunami catalogs including the possibility of large events in order to asses the tsunami hazard at the affected coastal regions. Finally, we show how an effective tsunami early warning could be achieved by the use of an array of high-precision real-time GNSS (Global Navigation Satellite System) receivers along the coast.

The 2009 Samoa-Tonga great earthquake triggered doublet

USGS Publications Warehouse

Lay, T.; Ammon, C.J.; Kanamori, H.; Rivera, L.; Koper, K.D.; Hutko, Alexander R.

2010-01-01

Great earthquakes (having seismic magnitudes of at least 8) usually involve abrupt sliding of rock masses at a boundary between tectonic plates. Such interplate ruptures produce dynamic and static stress changes that can activate nearby intraplate aftershocks, as is commonly observed in the trench-slope region seaward of a great subduction zone thrust event1-4. The earthquake sequence addressed here involves a rare instance in which a great trench-slope intraplate earthquake triggered extensive interplate faulting, reversing the typical pattern and broadly expanding the seismic and tsunami hazard. On 29 September 2009, within two minutes of the initiation of a normal faulting event with moment magnitude 8.1 in the outer trench-slope at the northern end of the Tonga subduction zone, two major interplate underthrusting subevents (both with moment magnitude 7.8), with total moment equal to a second great earthquake of moment magnitude 8.0, ruptured the nearby subduction zone megathrust. The collective faulting produced tsunami waves with localized regions of about 12metres run-up that claimed 192 lives in Samoa, American Samoa and Tonga. Overlap of the seismic signals obscured the fact that distinct faults separated by more than 50km had ruptured with different geometries, with the triggered thrust faulting only being revealed by detailed seismic wave analyses. Extensive interplate and intraplate aftershock activity was activated over a large region of the northern Tonga subduction zone. ?? 2010 Macmillan Publishers Limited. All rights reserved.

Preliminary Analysis of Remote Triggered Seismicity in Northern Baja California Generated by the 2011, Tohoku-Oki, Japan Earthquake

NASA Astrophysics Data System (ADS)

Wong-Ortega, V.; Castro, R. R.; Gonzalez-Huizar, H.; Velasco, A. A.

2013-05-01

We analyze possible variations of seismicity in the northern Baja California due to the passage of seismic waves from the 2011, M9.0, Tohoku-Oki, Japan earthquake. The northwestern area of Baja California is characterized by a mountain range composed of crystalline rocks. These Peninsular Ranges of Baja California exhibits high microseismic activity and moderate size earthquakes. In the eastern region of Baja California shearing between the Pacific and the North American plates takes place and the Imperial and Cerro-Prieto faults generate most of the seismicity. The seismicity in these regions is monitored by the seismic network RESNOM operated by the Centro de Investigación Científica y de Educación Superior de Ensenada (CICESE). This network consists of 13 three-component seismic stations. We use the seismic catalog of RESNOM to search for changes in local seismic rates occurred after the passing of surface waves generated by the Tohoku-Oki, Japan earthquake. When we compare one month of seismicity before and after the M9.0 earthquake, the preliminary analysis shows absence of triggered seismicity in the northern Peninsular Ranges and an increase of seismicity south of the Mexicali valley where the Imperial fault jumps southwest and the Cerro Prieto fault continues.

Earthquake catalog for estimation of maximum earthquake magnitude, Central and Eastern United States: Part A, Prehistoric earthquakes

USGS Publications Warehouse

Wheeler, Russell L.

2014-01-01

Computation of probabilistic earthquake hazard requires an estimate of Mmax, the maximum earthquake magnitude thought to be possible within a specified geographic region. This report is Part A of an Open-File Report that describes the construction of a global catalog of moderate to large earthquakes, from which one can estimate Mmax for most of the Central and Eastern United States and adjacent Canada. The catalog and Mmax estimates derived from it were used in the 2014 edition of the U.S. Geological Survey national seismic-hazard maps. This Part A discusses prehistoric earthquakes that occurred in eastern North America, northwestern Europe, and Australia, whereas a separate Part B deals with historical events.

Toward Building a New Seismic Hazard Model for Mainland China

NASA Astrophysics Data System (ADS)

Rong, Y.; Xu, X.; Chen, G.; Cheng, J.; Magistrale, H.; Shen, Z.

2015-12-01

At present, the only publicly available seismic hazard model for mainland China was generated by Global Seismic Hazard Assessment Program in 1999. We are building a new seismic hazard model by integrating historical earthquake catalogs, geological faults, geodetic GPS data, and geology maps. To build the model, we construct an Mw-based homogeneous historical earthquake catalog spanning from 780 B.C. to present, create fault models from active fault data using the methodology recommended by Global Earthquake Model (GEM), and derive a strain rate map based on the most complete GPS measurements and a new strain derivation algorithm. We divide China and the surrounding regions into about 20 large seismic source zones based on seismotectonics. For each zone, we use the tapered Gutenberg-Richter (TGR) relationship to model the seismicity rates. We estimate the TGR a- and b-values from the historical earthquake data, and constrain corner magnitude using the seismic moment rate derived from the strain rate. From the TGR distributions, 10,000 to 100,000 years of synthetic earthquakes are simulated. Then, we distribute small and medium earthquakes according to locations and magnitudes of historical earthquakes. Some large earthquakes are distributed on active faults based on characteristics of the faults, including slip rate, fault length and width, and paleoseismic data, and the rest to the background based on the distributions of historical earthquakes and strain rate. We evaluate available ground motion prediction equations (GMPE) by comparison to observed ground motions. To apply appropriate GMPEs, we divide the region into active and stable tectonics. The seismic hazard will be calculated using the OpenQuake software developed by GEM. To account for site amplifications, we construct a site condition map based on geology maps. The resulting new seismic hazard map can be used for seismic risk analysis and management, and business and land-use planning.

Evidence for Late Holocene earthquakes on the Utsalady Point fault, Northern Puget Lowland, Washington

USGS Publications Warehouse

Johnson, S.Y.; Nelson, A.R.; Personius, S.F.; Wells, R.E.; Kelsey, H.M.; Sherrod, B.L.; Okumura, K.; Koehler, R.; Witter, R.C.; Bradley, L.A.; Harding, D.J.

2004-01-01

Trenches across the Utsalady Point fault in the northern Puget Lowland of Washington reveal evidence of at least one and probably two late Holocene earthquakes. The "Teeka" and "Duffers" trenches were located along a 1.4-km-long, 1-to 4-m-high, northwest-trending, southwest-facing, topographic scarp recognized from Airborne Laser Swath Mapping. Glaciomarine drift exposed in the trenches reveals evidence of about 95 to 150 cm of vertical and 200 to 220 cm of left-lateral slip in the Teeka trench. Radiocarbon ages from a buried soil A horizon and overlying slope colluvium along with the historical record of earthquakes suggest that this faulting occurred 100 to 400 calendar years B.P. (A.D. 1550 to 1850). In the Duffers trench, 370 to 450 cm of vertical separation is accommodated by faulting (???210 cm) and folding (???160 to 240 cm), with probable but undetermined amounts of lateral slip. Stratigraphic relations and radiocarbon ages from buried soil, colluvium, and fissure fill in the hanging wall suggest the deformation at Duffers is most likely from two earthquakes that occurred between 100 to 500 and 1100 to 2200 calendar years B.P., but deformation during a single earthquake is also possible. For the two-earthquake hypothesis, deformation at Teeka trench in the first event involved folding but not faulting. Regional relations suggest that the earthquake(s) were M ??? ???6.7 and that offshore rupture may have produced tsunamis. Based on this investigation and related recent studies, the maximum recurrence interval for large ground-rupturing crustal-fault earthquakes in the Puget Lowland is about 400 to 600 years or less.

Comparison of the historical record of earthquake hazard with seismic-hazard models for New Zealand and the continental United States

USGS Publications Warehouse

Stirling, M.; Petersen, M.

2006-01-01

We compare the historical record of earthquake hazard experienced at 78 towns and cities (sites) distributed across New Zealand and the continental United States with the hazard estimated from the national probabilistic seismic-hazard (PSH) models for the two countries. The two PSH models are constructed with similar methodologies and data. Our comparisons show a tendency for the PSH models to slightly exceed the historical hazard in New Zealand and westernmost continental United States interplate regions, but show lower hazard than that of the historical record in the continental United States intraplate region. Factors such as non-Poissonian behavior, parameterization of active fault data in the PSH calculations, and uncertainties in estimation of ground-motion levels from historical felt intensity data for the interplate regions may have led to the higher-than-historical levels of hazard at the interplate sites. In contrast, the less-than-historical hazard for the remaining continental United States (intraplate) sites may be largely due to site conditions not having been considered at the intraplate sites, and uncertainties in correlating ground-motion levels to historical felt intensities. The study also highlights the importance of evaluating PSH models at more than one region, because the conclusions reached on the basis of a solely interplate or intraplate study would be very different.

What can we learn from the Wells, NV earthquake sequence about seismic hazard in the intermountain west?

USGS Publications Warehouse

Petersen, M.D.; Pankow, K.L.; Biasi, G.P.; Meremonte, M.

2008-01-01

The February 21, 2008 Wells, NV earthquake (M 6) was felt throughout eastern Nevada, southern Idaho, and western Utah. The town of Wells sustained significant damage to unreinforced masonry buildings. The earthquake occurred in a region of low seismic hazard with little seismicity, low geodetic strain rates, and few mapped faults. The peak horizontal ground acceleration predicted by the USGS National Seismic Hazard Maps is about 0.2 g at 2% probability of exceedance in 50 years, with the contributions coming mostly from the Ruby Mountain fault and background seismicity (M5-7.0). The hazard model predicts that the probability of occurrence of an M>6 event within 50 km of Wells is about 15% in 100 years. Although the earthquake was inside the USArray Transportable Array network, the nearest on-scale recordings of ground motions from the mainshock were too distant to estimate accelerations in town. The University of Nevada Reno, the University of Utah, and the U.S. Geological Survey deployed portable instruments to capture the ground motions from aftershocks of this rare normal-faulting event. Shaking from a M 4.7 aftershock recorded on portable instruments at distances less than 10 km exceeded 0.3 g, and sustained accelerations above 0.1 g lasted for about 5 seconds. For a magnitude 5 earthquake at 10 km distance the NGA equations predict median peak ground accelerations about 0.1 g. Ground motions from normal faulting earthquakes are poorly represented in the ground motion prediction equations. We compare portable and Transportable Array ground-motion recordings with prediction equations. Advanced National Seismic System stations in Utah recorded ground motions 250 km from the mainshock of about 2% g. The maximum ground motion recorded in Salt Lake City was in the center of the basin. We analyze the spatial variability of ground motions (rock vs. soil) and the influence of the Salt Lake Basin in modifying the ground motions. We then compare this data with the

Lessons from the conviction of the L'Aquila seven: The standard probabilistic earthquake hazard and risk assessment is ineffective

NASA Astrophysics Data System (ADS)

Wyss, Max

2013-04-01

An earthquake of M6.3 killed 309 people in L'Aquila, Italy, on 6 April 2011. Subsequently, a judge in L'Aquila convicted seven who had participated in an emergency meeting on March 30, assessing the probability of a major event to follow the ongoing earthquake swarm. The sentence was six years in prison, a combine fine of 2 million Euros, loss of job, loss of retirement rent, and lawyer's costs. The judge followed the prosecution's accusation that the review by the Commission of Great Risks had conveyed a false sense of security to the population, which consequently did not take their usual precautionary measures before the deadly earthquake. He did not consider the facts that (1) one of the convicted was not a member of the commission and had merrily obeyed orders to bring the latest seismological facts to the discussion, (2) another was an engineer who was not required to have any expertise regarding the probability of earthquakes, (3) and two others were seismologists not invited to speak to the public at a TV interview and a press conference. This exaggerated judgment was the consequence of an uproar in the population, who felt misinformed and even mislead. Faced with a population worried by an earthquake swarm, the head of the Italian Civil Defense is on record ordering that the population be calmed, and the vice head executed this order in a TV interview one hour before the meeting of the Commission by stating "the scientific community continues to tell me that the situation is favorable and that there is a discharge of energy." The first lesson to be learned is that communications to the public about earthquake hazard and risk must not be left in the hands of someone who has gross misunderstandings about seismology. They must be carefully prepared by experts. The more significant lesson is that the approach to calm the population and the standard probabilistic hazard and risk assessment, as practiced by GSHAP, are misleading. The later has been criticized as

Guide to Geologic Hazards in Alaska | Alaska Division of Geological &

Science.gov Websites

content Guide to Geologic Hazards in Alaska Glossary Coastal and river hazards image Coastal and river Storm surge Tsunami Earthquake related hazards image Earthquake related hazards Earthquake Earthquake Subsidence Surface fault rupture Tsunami Uplift Glacier hazards image Glacier hazards Avalanche Debris flow

Data Sets and Data Services at the Northern California Earthquake Data Center

NASA Astrophysics Data System (ADS)

Neuhauser, D. S.; Zuzlewski, S.; Allen, R. M.

2014-12-01

The Northern California Earthquake Data Center (NCEDC) houses a unique and comprehensive data archive and provides real-time services for a variety of seismological and geophysical data sets that encompass northern and central California. We have over 80 terabytes of continuous and event-based time series data from broadband, short-period, strong motion, and strain sensors as well as continuous and campaign GPS data at both standard and high sample rates in both raw and RINEX format. The Northen California Seismic System (NCSS), operated by UC Berkeley and USGS Menlo Park, has recorded over 890,000 events from 1984 to the present, and the NCEDC provides catalog, parametric information, moment tensors and first motion mechanisms, and time series data for these events. We also host and provide event catalogs, parametric information, and event waveforms for DOE enhanced geothermal system monitoring in northern California and Nevada. The NCEDC provides a variety of ways for users to access these data. The most recent development are web services, which provide interactive, command-line, or program-based workflow access to data. Web services use well-established server and client protocols and RESTful software architecture that allow users to easily submit queries and receive the requested data in real-time rather than through batch or email-based requests. Data are returned to the user in the appropriate format such as XML, RESP, simple text, or MiniSEED depending on the service and selected output format. The NCEDC supports all FDSN-defined web services as well as a number of IRIS-defined and NCEDC-defined services. We also continue to support older email-based and browser-based access to data. NCEDC data and web services can be found at http://www.ncedc.org and http://service.ncedc.org.

Deterministic seismic hazard macrozonation of India

NASA Astrophysics Data System (ADS)

Kolathayar, Sreevalsa; Sitharam, T. G.; Vipin, K. S.

2012-10-01

Earthquakes are known to have occurred in Indian subcontinent from ancient times. This paper presents the results of seismic hazard analysis of India (6°-38°N and 68°-98°E) based on the deterministic approach using latest seismicity data (up to 2010). The hazard analysis was done using two different source models (linear sources and point sources) and 12 well recognized attenuation relations considering varied tectonic provinces in the region. The earthquake data obtained from different sources were homogenized and declustered and a total of 27,146 earthquakes of moment magnitude 4 and above were listed in the study area. The sesismotectonic map of the study area was prepared by considering the faults, lineaments and the shear zones which are associated with earthquakes of magnitude 4 and above. A new program was developed in MATLAB for smoothing of the point sources. For assessing the seismic hazard, the study area was divided into small grids of size 0.1° × 0.1° (approximately 10 × 10 km), and the hazard parameters were calculated at the center of each of these grid cells by considering all the seismic sources within a radius of 300 to 400 km. Rock level peak horizontal acceleration (PHA) and spectral accelerations for periods 0.1 and 1 s have been calculated for all the grid points with a deterministic approach using a code written in MATLAB. Epistemic uncertainty in hazard definition has been tackled within a logic-tree framework considering two types of sources and three attenuation models for each grid point. The hazard evaluation without logic tree approach also has been done for comparison of the results. The contour maps showing the spatial variation of hazard values are presented in the paper.

A GIS-based time-dependent seismic source modeling of Northern Iran

NASA Astrophysics Data System (ADS)

Hashemi, Mahdi; Alesheikh, Ali Asghar; Zolfaghari, Mohammad Reza

2017-01-01

The first step in any seismic hazard study is the definition of seismogenic sources and the estimation of magnitude-frequency relationships for each source. There is as yet no standard methodology for source modeling and many researchers have worked on this topic. This study is an effort to define linear and area seismic sources for Northern Iran. The linear or fault sources are developed based on tectonic features and characteristic earthquakes while the area sources are developed based on spatial distribution of small to moderate earthquakes. Time-dependent recurrence relationships are developed for fault sources using renewal approach while time-independent frequency-magnitude relationships are proposed for area sources based on Poisson process. GIS functionalities are used in this study to introduce and incorporate spatial-temporal and geostatistical indices in delineating area seismic sources. The proposed methodology is used to model seismic sources for an area of about 500 by 400 square kilometers around Tehran. Previous researches and reports are studied to compile an earthquake/fault catalog that is as complete as possible. All events are transformed to uniform magnitude scale; duplicate events and dependent shocks are removed. Completeness and time distribution of the compiled catalog is taken into account. The proposed area and linear seismic sources in conjunction with defined recurrence relationships can be used to develop time-dependent probabilistic seismic hazard analysis of Northern Iran.

A Case Study of Geologic Hazards Affecting School Buildings: Evaluating Seismic Structural Vulnerability and Landslide Hazards at Schools in Aizawl, India

NASA Astrophysics Data System (ADS)

Perley, M. M.; Guo, J.

2016-12-01

India's National School Safety Program (NSSP) aims to assess all government schools in earthquake prone regions of the country. To supplement the Mizoram State Government's recent survey of 141 government schools, we screened an additional 16 private and 4 government schools for structural vulnerabilities due to earthquakes, as well as landslide hazards, in Mizoram's capital of Aizawl. We developed a geomorphologically derived landslide susceptibility matrix, which was cross-checked with Aizawl Municipal Corporation's landslide hazard map (provided by Lettis Consultants International), to determine the geologic hazards at each school. Our research indicates that only 7% of the 22 assessed school buildings are located within low landslide hazard zones; 64% of the school buildings, with approximately 9,500 students, are located within very high or high landslide hazard zones. Rapid Visual Screening (RVS) was used to determine the structural earthquake vulnerability of each school building. RVS is an initial vulnerability assessment procedure used to inventory and rank buildings that may be hazardous during an earthquake. Our study indicates that all of the 22 assessed school buildings have a damageability rating of Grade 3 or higher on the 5-grade EMS scale, suggesting a significant vulnerability and potential for damage in buildings, ranging from widespread cracking of columns and beam column joints to collapse. Additionally, 86% of the schools we visited had reinforced concrete buildings constructed before Aizawl's building regulations were passed in 2007, which can be assumed to lack appropriate seismic reinforcement. Using our findings, we will give recommendations to the Government of Mizoram to prevent unnecessary loss of life by minimizing each school's landslide risk and ensuring schools are earthquake-resistant.

Southern California Earthquake Center (SCEC) Communication, Education and Outreach Program

NASA Astrophysics Data System (ADS)

Benthien, M. L.

2003-12-01

The SCEC Communication, Education, and Outreach Program (CEO) offers student research experiences, web-based education tools, classroom curricula, museum displays, public information brochures, online newsletters, and technical workshops and publications. This year, much progress has been made on the development of the Electronic Encyclopedia of Earthquakes (E3), a collaborative project with CUREE and IRIS. The E3 development system is now fully operational, and 165 entries are in the pipeline. When complete, information and resources for over 500 Earth science and engineering topics will be included, with connections to curricular materials useful for teaching Earth Science, engineering, physics and mathematics. To coordinate activities for the 10-year anniversary of the Northridge Earthquake in 2004 (and beyond), the "Earthquake Country Alliance" is being organized by SCEC CEO to present common messages, to share or promote existing resources, and to develop new activities and products jointly (such as a new version of Putting Down Roots in Earthquake Country). The group includes earthquake science and engineering researchers and practicing professionals, preparedness experts, response and recovery officials, news media representatives, and education specialists. A web portal, http://www.earthquakecountry.info, is being developed established with links to web pages and descriptions of other resources and services that the Alliance members provide. Another ongoing strength of SCEC is the Summer Intern program, which now has a year-round counterpart with students working on IT projects at USC. Since Fall 2002, over 32 students have participated in the program, including 7 students working with scientists throughout SCEC, 17 students involved in the USC "Earthquake Information Technology" intern program, and 7 students involved in CEO projects. These and other activities of the SCEC CEO program will be presented, along with lessons learned during program design and

Italian Case Studies Modelling Complex Earthquake Sources In PSHA

NASA Astrophysics Data System (ADS)

Gee, Robin; Peruzza, Laura; Pagani, Marco

2017-04-01

This study presents two examples of modelling complex seismic sources in Italy, done in the framework of regional probabilistic seismic hazard assessment (PSHA). The first case study is for an area centred around Collalto Stoccaggio, a natural gas storage facility in Northern Italy, located within a system of potentially seismogenic thrust faults in the Venetian Plain. The storage exploits a depleted natural gas reservoir located within an actively growing anticline, which is likely driven by the Montello Fault, the underlying blind thrust. This fault has been well identified by microseismic activity (M<2) detected by a local seismometric network installed in 2012 (http://rete-collalto.crs.inogs.it/). At this time, no correlation can be identified between the gas storage activity and local seismicity, so we proceed with a PSHA that considers only natural seismicity, where the rates of earthquakes are assumed to be time-independent. The source model consists of faults and distributed seismicity to consider earthquakes that cannot be associated to specific structures. All potentially active faults within 50 km of the site are considered, and are modelled as 3D listric surfaces, consistent with the proposed geometry of the Montello Fault. Slip rates are constrained using available geological, geophysical and seismological information. We explore the sensitivity of the hazard results to various parameters affected by epistemic uncertainty, such as ground motions prediction equations with different rupture-to-site distance metrics, fault geometry, and maximum magnitude. The second case is an innovative study, where we perform aftershock probabilistic seismic hazard assessment (APSHA) in Central Italy, following the Amatrice M6.1 earthquake of August 24th, 2016 (298 casualties) and the subsequent earthquakes of Oct 26th and 30th (M6.1 and M6.6 respectively, no deaths). The aftershock hazard is modelled using a fault source with complex geometry, based on literature data

Determining on-fault earthquake magnitude distributions from integer programming

NASA Astrophysics Data System (ADS)

Geist, Eric L.; Parsons, Tom

2018-02-01

Earthquake magnitude distributions among faults within a fault system are determined from regional seismicity and fault slip rates using binary integer programming. A synthetic earthquake catalog (i.e., list of randomly sampled magnitudes) that spans millennia is first formed, assuming that regional seismicity follows a Gutenberg-Richter relation. Each earthquake in the synthetic catalog can occur on any fault and at any location. The objective is to minimize misfits in the target slip rate for each fault, where slip for each earthquake is scaled from its magnitude. The decision vector consists of binary variables indicating which locations are optimal among all possibilities. Uncertainty estimates in fault slip rates provide explicit upper and lower bounding constraints to the problem. An implicit constraint is that an earthquake can only be located on a fault if it is long enough to contain that earthquake. A general mixed-integer programming solver, consisting of a number of different algorithms, is used to determine the optimal decision vector. A case study is presented for the State of California, where a 4 kyr synthetic earthquake catalog is created and faults with slip ≥3 mm/yr are considered, resulting in >106 variables. The optimal magnitude distributions for each of the faults in the system span a rich diversity of shapes, ranging from characteristic to power-law distributions.

Determining on-fault earthquake magnitude distributions from integer programming

USGS Publications Warehouse

Geist, Eric L.; Parsons, Thomas E.

2018-01-01

Earthquake magnitude distributions among faults within a fault system are determined from regional seismicity and fault slip rates using binary integer programming. A synthetic earthquake catalog (i.e., list of randomly sampled magnitudes) that spans millennia is first formed, assuming that regional seismicity follows a Gutenberg-Richter relation. Each earthquake in the synthetic catalog can occur on any fault and at any location. The objective is to minimize misfits in the target slip rate for each fault, where slip for each earthquake is scaled from its magnitude. The decision vector consists of binary variables indicating which locations are optimal among all possibilities. Uncertainty estimates in fault slip rates provide explicit upper and lower bounding constraints to the problem. An implicit constraint is that an earthquake can only be located on a fault if it is long enough to contain that earthquake. A general mixed-integer programming solver, consisting of a number of different algorithms, is used to determine the optimal decision vector. A case study is presented for the State of California, where a 4 kyr synthetic earthquake catalog is created and faults with slip ≥3 mm/yr are considered, resulting in >106  variables. The optimal magnitude distributions for each of the faults in the system span a rich diversity of shapes, ranging from characteristic to power-law distributions. 

An Earthquake Education Program with Parent Participation for Preschool Children

ERIC Educational Resources Information Center

Gulay, Hulya

2010-01-01

The purpose of this study was to determine the effects of the earthquake education program which was prepared for 5 to 6 year old children and to draw attention to the importance of parent participation. The earthquake education program was applied to 93 children and 31 parents in the province of Denizli situated in the first degree seismic zone…

An Arduino project to record ground motion and to learn on earthquake hazard at high school

NASA Astrophysics Data System (ADS)

Saraò, Angela; Barnaba, Carla; Clocchiatti, Marco; Zuliani, David

2015-04-01

Through a multidisciplinary work that integrates Technology education with Earth Sciences, we implemented an educational program to raise the students' awareness of seismic hazard and to disseminate good practices of earthquake safety. Using free software and low-cost open hardware, the students of a senior class of the high school Liceo Paschini in Tolmezzo (NE Italy) implemented a seismograph using the Arduino open-source electronics platform and the ADXL345 sensors to emulate a low cost seismometer (e.g. O-NAVI sensor of the Quake-Catcher Network, http://qcn.stanford.edu). To accomplish their task the students were addressed to use the web resources for technical support and troubleshooting. Shell scripts, running on local computers under Linux OS, controlled the process of recording and display data. The main part of the experiment was documented using the DokuWiki style. Some propaedeutic lessons in computer sciences and electronics were needed to build up the necessary skills of the students and to fill in the gap of their background knowledge. In addition lectures by seismologists and laboratory activity allowed the class to exploit different aspects of the physics of the earthquake and particularly of the seismic waves, and to become familiar with the topics of seismic hazard through an inquiry-based learning. The Arduino seismograph achieved can be used for educational purposes and it can display tremors on the local network of the school. For sure it can record the ground motion due to a seismic event that can occur in the area, but further improvements are necessary for a quantitative analysis of the recorded signals.

Leveraging geodetic data to reduce losses from earthquakes

USGS Publications Warehouse

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

Near-shore Evaluation of Holocene Faulting and Earthquake Hazard in the New York City Metropolitan Region

NASA Astrophysics Data System (ADS)

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

2016-12-01

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

88 hours: the U.S. Geological Survey National Earthquake Information Center response to the March 11, 2011 Mw 9.0 Tohoku earthquake

USGS Publications Warehouse

Wald, David J.; Hayes, Gavin P.; Benz, Harley M.; Earle, Paul S.; Briggs, Richard W.

2011-01-01

The M 9.0 11 March 2011 Tohoku, Japan, earthquake and associated tsunami near the east coast of the island of Honshu caused tens of thousands of deaths and potentially over one trillion dollars in damage, resulting in one of the worst natural disasters ever recorded. The U.S. Geological Survey National Earthquake Information Center (USGS NEIC), through its responsibility to respond to all significant global earthquakes as part of the National Earthquake Hazards Reduction Program, quickly produced and distributed a suite of earthquake information products to inform emergency responders, the public, the media, and the academic community of the earthquake's potential impact and to provide scientific background for the interpretation of the event's tectonic context and potential for future hazard. Here we present a timeline of the NEIC response to this devastating earthquake in the context of rapidly evolving information emanating from the global earthquake-response community. The timeline includes both internal and publicly distributed products, the relative timing of which highlights the inherent tradeoffs between the requirement to provide timely alerts and the necessity for accurate, authoritative information. The timeline also documents the iterative and evolutionary nature of the standard products produced by the NEIC and includes a behind-the-scenes look at the decisions, data, and analysis tools that drive our rapid product distribution.

Methodologies for the assessment of earthquake-triggered landslides hazard. A comparison of Logistic Regression and Artificial Neural Network models.

NASA Astrophysics Data System (ADS)

García-Rodríguez, M. J.; Malpica, J. A.; Benito, B.

2009-04-01

In recent years, interest in landslide hazard assessment studies has increased substantially. They are appropriate for evaluation and mitigation plan development in landslide-prone areas. There are several techniques available for landslide hazard research at a regional scale. Generally, they can be classified in two groups: qualitative and quantitative methods. Most of qualitative methods tend to be subjective, since they depend on expert opinions and represent hazard levels in descriptive terms. On the other hand, quantitative methods are objective and they are commonly used due to the correlation between the instability factors and the location of the landslides. Within this group, statistical approaches and new heuristic techniques based on artificial intelligence (artificial neural network (ANN), fuzzy logic, etc.) provide rigorous analysis to assess landslide hazard over large regions. However, they depend on qualitative and quantitative data, scale, types of movements and characteristic factors used. We analysed and compared an approach for assessing earthquake-triggered landslides hazard using logistic regression (LR) and artificial neural networks (ANN) with a back-propagation learning algorithm. One application has been developed in El Salvador, a country of Central America where the earthquake-triggered landslides are usual phenomena. In a first phase, we analysed the susceptibility and hazard associated to the seismic scenario of the 2001 January 13th earthquake. We calibrated the models using data from the landslide inventory for this scenario. These analyses require input variables representing physical parameters to contribute to the initiation of slope instability, for example, slope gradient, elevation, aspect, mean annual precipitation, lithology, land use, and terrain roughness, while the occurrence or non-occurrence of landslides is considered as dependent variable. The results of the landslide susceptibility analysis are checked using landslide

Geological-Seismological Evaluation of Earthquake Hazards for Appurtenant Structures at Gathright Dam, Virginia

DTIC Science & Technology

1990-07-01

1979, Late Holocene faulting and earthquake recurrence in the Reelfoot Lake area, northwestern Tennessee, Bull, Geol. Soc. Am.. vol. J. pp. 1013-1018...upstream from Covington, Virginia. The dam is located in northern Alleghany County and the majority of the reservoir, Lake Moomaw, is located in southern...Bath County. Lake Moomaw is approximately 12 miles (19 km) long and ranges from less than 1/4 to 1-1/2 miles (1/2 to 2-1/2 km) in width. Gathright Dam

Progress report on the Worldwide Earthquake Risk Management (WWERM) Program

USGS Publications Warehouse

Algermissen, S.T.; Hays, Walter W.; Krumpe, Paul R.

1992-01-01

Considerable progress has been made in the Worldwide Earthquake Risk Management (WWERM) Program since its initiation in late 1989 as a cooperative program of the Agency for International Development (AID), Office of U.S. Foreign Disaster Assistance (OFDA), and the U.S. Geological Survey. Probabilistic peak acceleration and peak Modified Mercalli intensity (MMI) maps have been prepared for Chile and for Sulawesi province in Indonesia. Earthquake risk (loss) studies for dwellings in Gorontalo, North Sulawesi, have been completed and risk studies for dwellings in selected areas of central Chile are underway. A special study of the effect of site response on earthquake ground motion estimation in central Chile has also been completed and indicates that site response may modify the ground shaking by as much as plus or minus two units of MMI. A program for the development of national probabilistic ground motion maps for the Philippines is now underway and pilot studies of earthquake ground motion and risk are being planned for Morocco.

Tide gauge observations of the Indian Ocean tsunami, December 26, 2004

NASA Astrophysics Data System (ADS)

Merrifield, M. A.; Firing, Y. L.; Aarup, T.; Agricole, W.; Brundrit, G.; Chang-Seng, D.; Farre, R.; Kilonsky, B.; Knight, W.; Kong, L.; Magori, C.; Manurung, P.; McCreery, C.; Mitchell, W.; Pillay, S.; Schindele, F.; Shillington, F.; Testut, L.; Wijeratne, E. M. S.; Caldwell, P.; Jardin, J.; Nakahara, S.; Porter, F.-Y.; Turetsky, N.

2005-05-01

The magnitude 9.0 earthquake centered off the west coast of northern Sumatra (3.307°N, 95.947°E) on December 26, 2004 at 00:59 UTC (United States Geological Survey (USGS) (2005), USGS Earthquake Hazards Program-Latest Earthquakes, Earthquake Hazards Program, http://earthquake.usgs.gov/eqinthenews/2004/usslav/, 2005) generated a series of tsunami waves that devastated coastal areas throughout the Indian Ocean. Tide gauges operated on behalf of national and international organizations recorded the wave form at a number of island and continental locations. This report summarizes the tide gauge observations of the tsunami in the Indian Ocean (available as of January 2005) and provides a recommendation for the use of the basin-wide tide gauge network for future warnings.

Seismic Awareness : Transportation Facilities : A Primer for Transportation Managers on Earthquake Hazards and Measures for Reducing Vulnerability

DOT National Transportation Integrated Search

1993-12-01

The purpose of this report is to alert managers and operators of transportation enterprises, in both the public and private sector, to the dangers of earthquakes to buildings and possible precautions to be taken. The nature of seismic hazards in the ...

Timing of paleoearthquakes on the northern Hayward Fault: preliminary evidence in El Cerrito, California

USGS Publications Warehouse

Lienkaemper, J.J.; Schwartz, D.P.; Kelson, K.I.; Lettis, W.R.; Simpson, Gary D.; Southon, J.R.; Wanket, J.A.; Williams, P.L.

1999-01-01

The Working Group on California Earthquake Probabilities estimated that the northern Hayward fault had the highest probability (0.28) of producing a M7 Bay Area earthquake in 30 years (WGCEP, 1990). This probability was based, in part, on the assumption that the last large earthquake occurred on this segment in 1836. However, a recent study of historical documents concludes that the 1836 earthquake did not occur on the northern Hayward fault, thereby extending the elapsed time to at least 220 yr ago, the beginning of the written record. The average recurrence interval for a M7 on the northern Hayward is unknown. WGCEP (1990) assumed an interval of 167 years. The 1996 Working Group on Northern California Earthquake Potential estimated ~210 yr, based on extrapolations from southern Hayward paleoseismological studies and a revised estimate of 1868 slip on the southern Hayward fault. To help constrain the timing of paleoearthquakes on the northern Hayward fault for the 1999 Bay Area probability update, we excavated two trenches that cross the fault and a sag pond on the Mira Vista golf course. As the site is on the second fairway, we were limited to less than ten days to document these trenches. Analysis was aided by rapid C-14 dating of more than 90 samples which gave near real-time results with the trenches still open. A combination of upward fault terminations, disrupted strata, and discordant angular relations indicates at least four, and possibly seven or more, surface faulting earthquakes occurred during a 1630-2130 yr interval. Hence, average recurrence time could be <270 yr, but is no more than 710 yr. The most recent earthquake (MRE) occurred after AD 1640. Preliminary analysis of calibrated dates supports the assumption that no large historical (post-1776) earthquakes have ruptured the surface here, but the youngest dates need more corroboration. Analyses of pollen for presence of non-native species help to constrain the time of the MRE. The earthquake

ShakeMap Atlas 2.0: an improved suite of recent historical earthquake ShakeMaps for global hazard analyses and loss model calibration

USGS Publications Warehouse

Garcia, D.; Mah, R.T.; Johnson, K.L.; Hearne, M.G.; Marano, K.D.; Lin, K.-W.; Wald, D.J.

2012-01-01

We introduce the second version of the U.S. Geological Survey ShakeMap Atlas, which is an openly-available compilation of nearly 8,000 ShakeMaps of the most significant global earthquakes between 1973 and 2011. This revision of the Atlas includes: (1) a new version of the ShakeMap software that improves data usage and uncertainty estimations; (2) an updated earthquake source catalogue that includes regional locations and finite fault models; (3) a refined strategy to select prediction and conversion equations based on a new seismotectonic regionalization scheme; and (4) vastly more macroseismic intensity and ground-motion data from regional agencies All these changes make the new Atlas a self-consistent, calibrated ShakeMap catalogue that constitutes an invaluable resource for investigating near-source strong ground-motion, as well as for seismic hazard, scenario, risk, and loss-model development. To this end, the Atlas will provide a hazard base layer for PAGER loss calibration and for the Earthquake Consequences Database within the Global Earthquake Model initiative.

Ground motions from induced earthquakes in Oklahoma and Kansas and the implications for seismic hazard

NASA Astrophysics Data System (ADS)

Moschetti, M. P.; Rennolet, S.; Thompson, E.; Yeck, W.; McNamara, D. E.; Herrmann, R. B.; Powers, P.; Hoover, S. M.

2016-12-01

Recent efforts to characterize the seismic hazard resulting from increased seismicity rates in Oklahoma and Kansas highlight the need for a regionalized ground motion characterization. To support these efforts, we measure and compile strong ground motions and compare these average ground motions intensity measures (IMs) with existing ground motion prediction equations (GMPEs). IMs are computed for available broadband and strong-motion records from M≥3 earthquakes occurring January 2009-April 2016, using standard strong motion processing guidelines. We verified our methods by comparing results from specific earthquakes to other standard procedures such as the USGS Shakemap system. The large number of records required an automated processing scheme, which was complicated by the extremely high rate of small-magnitude earthquakes 2014-2016. Orientation-independent IMs include peak ground motions (acceleration and velocity) and pseudo-spectral accelerations (5 percent damping, 0.1-10 s period). Metadata for the records included relocated event hypocenters. The database includes more than 160,000 records from about 3200 earthquakes. Estimates of the mean and standard deviation of the IMs are computed by distance binning at intervals of 2 km. Mean IMs exhibit a clear break in geometrical attenuation at epicentral distances of about 50-70 km, which is consistent with previous studies in the CEUS. Comparisons of these ground motions with modern GMPEs provide some insight into the relative IMs of induced earthquakes in Oklahoma and Kansas relative to the western U.S. and the central and eastern U.S. The site response for these stations is uncertain because very little is known about shallow seismic velocity in the region, and we make no attempt to correct observed IMs to a reference site conditions. At close distances, the observed IMs are lower than the predictions of the seed GMPEs of the NGA-East project (and about consistent with NGA-West-2 ground motions). This ground

Evolution of earthquake-triggered landslides in the Kashmir Himalaya, northern Pakistan

USGS Publications Warehouse

Khattak, G.A.; Owen, L.A.; Kamp, U.; Harp, E.L.

2010-01-01

The influence of the 08 October 2005 Kashmir earthquake and subsequent snow melt and monsoon rainfall on slope stability was evaluated using repeat photography in the Kashmir Himalaya of northern Pakistan. Sixty-eight landslide-affected locations were selected and photographed in November 2005, May/June 2006, June 2007, and August 2007 to evaluate all potential geomorphic changes. Eighty percent of the locations showed no or very little change, 11% of the locations showed a partial vegetation recovery on the slopes, while 9% showed an increase in the landslide area. All those locations that showed an increase in landsliding were located along rivers and/or roads. The small change in landslide extent is remarkable given that the region experienced one of the heaviest monsoon seasons in the last decade and is counter to earlier predictions of accelerated slope erosion by landsliding in the immediate years following the earthquake. Extensive fissures and ground cracks at many localities, however, still present a potential of future landsliding under wetter conditions. ?? 2009 Elsevier B.V. All rights reserved.

Earthquake recordings from the 2002 Seattle Seismic Hazard Investigation of Puget Sound (SHIPS), Washington State

USGS Publications Warehouse

Pratt, Thomas L.; Meagher, Karen L.; Brocher, Thomas M.; Yelin, Thomas; Norris, Robert; Hultgrien, Lynn; Barnett, Elizabeth; Weaver, Craig S.

2003-01-01

This report describes seismic data obtained during the fourth Seismic Hazard Investigation of Puget Sound (SHIPS) experiment, termed Seattle SHIPS . The experiment was designed to study the influence of the Seattle sedimentary basin on ground shaking during earthquakes. To accomplish this, we deployed seismometers over the basin to record local earthquakes, quarry blasts, and teleseisms during the period of January 26 to May 27, 2002. We plan to analyze the recordings to compute spectral amplitudes at each site, to determine the variability of ground motions over the basin. During the Seattle SHIPS experiment, seismometers were deployed at 87 sites in a 110-km-long east-west line, three north-south lines, and a grid throughout the Seattle urban area (Figure 1). At each of these sites, an L-22, 2-Hz velocity transducer was installed and connected to a REF TEK Digital Acquisition System (DAS), both provided by the Program for Array Seismic Studies of the Continental Lithosphere (PASSCAL) of the Incorporated Research Institutes for Seismology (IRIS). The instruments were installed on January 26 and 27, and were retrieved gradually between April 18 and May 27. All instruments continuously sampled all three components of motion (velocity) at a sample rate of 50 samples/sec. To ensure accurate computations of amplitude, we calibrated the geophones in situ to obtain the instrument responses. In this report, we discuss the acquisition of these data, we describe the processing and merging of these data into 1-hour long traces and into windowed events, we discuss the geophone calibration process and its results, and we display some of the earthquake recordings.

Missing great earthquakes

USGS Publications Warehouse

Hough, Susan E.

2013-01-01

The occurrence of three earthquakes with moment magnitude (Mw) greater than 8.8 and six earthquakes larger than Mw 8.5, since 2004, has raised interest in the long-term global rate of great earthquakes. Past studies have focused on the analysis of earthquakes since 1900, which roughly marks the start of the instrumental era in seismology. Before this time, the catalog is less complete and magnitude estimates are more uncertain. Yet substantial information is available for earthquakes before 1900, and the catalog of historical events is being used increasingly to improve hazard assessment. Here I consider the catalog of historical earthquakes and show that approximately half of all Mw ≥ 8.5 earthquakes are likely missing or underestimated in the 19th century. I further present a reconsideration of the felt effects of the 8 February 1843, Lesser Antilles earthquake, including a first thorough assessment of felt reports from the United States, and show it is an example of a known historical earthquake that was significantly larger than initially estimated. The results suggest that incorporation of best available catalogs of historical earthquakes will likely lead to a significant underestimation of seismic hazard and/or the maximum possible magnitude in many regions, including parts of the Caribbean.

Reconnaissance engineering geology of Sitka and vicinity, Alaska, with emphasis on evaluation of earthquake and other geologic hazards

USGS Publications Warehouse

Yehle, Lynn A.

1974-01-01

A program to study the engineering geology of most of the larger Alaska coastal communities and to evaluate their earthquake and other geologic hazards was started following the 1964 Alaska earthquake; this report about Sitka and vicinity is a product of that program. Field-study methods were of a reconnaissance nature, and thus the interpretations in the report are subject to revision as further information becomes available. This report can provide broad geologic guidelines for planners and engineers during preparation of land-use plans. The use of this information should lead to minimizing future loss of life and property due to geologic hazards, especially during very large earthquakes. Landscape of Sitka and surrounding area is characterized by numerous islands and a narrow strip of gently rolling ground adjacent to rugged mountains; steep valleys and some fiords cut sharply into the mountains. A few valley floors are wide and flat and grade into moderate-sized deltas. Glaciers throughout southeastern Alaska and elsewhere became vastly enlarged during the Pleistocene Epoch. The Sitka area presumably was covered by ice several times; glaciers deeply eroded some valleys and removed fractured bedrock along some faults. The last major deglaciation occurred sometime before 10,000 years ago. Crustal rebound believed to be related to glacial melting caused land emergence at Sitka of at least 35 feet (10.7 m) relative to present sea level. Bedrock at Sitka and vicinity is composed mostly of bedded, hard, dense graywacke and some argillite. Beds strike predominantly northwest and are vertical or steeply dipping. Locally, bedded rocks are cut by dikes of fine-grained igneous rock. Host bedrock is of Jurassic and Cretaceous age. Eight types of surficial deposits of Quaternary age were recognized. Below altitudes of 3S feet (10.7 m), the dominant deposits are those of modern and elevated shores and deltas; at higher altitudes, widespread muskeg overlies a mantle of

Basal erosion: barrier to earthquake propagation? Insight from the northern chilean forearc

NASA Astrophysics Data System (ADS)

Cubas, N.

2017-12-01

Subducted topographic features have often been suspected as barriers to large earthquake propagation. These features would induce basal erosion, leading to a large network of fractures impeding large nucleation or shear localization. Looking for correlation between basal erosion and megathrust ruptures is thus critical nowadays to understand earthquake mechanics and infer rupture scenarios. In this study, we propose to seek possible location of basal erosion from the forearc morphology by applying the critical taper theory. We focus on the North Chile subduction zone that has experienced four major earthquakes during the last two decades and where basal erosion and seamount subduction have already been suspected. Basal erosion should occur when the basal friction approaches the internal friction. We thus seek what part of the forearc is at critical state and select areas for which the two frictions are almost equal. We find a large band, located at 25km depth, from the Mejillones peninsula to the Iquique region at critical state with very high basal friction. The critical areas seem to surround the Tocopilla 2007 Mw 7.7 and the Iquique 2014 Mw 8.1 ruptures. When compared with the interseismic coupling, except for the Tocopilla segment, the critical areas are located in low-coupled zones. More interestingly, the reported normal faults of the forearc do not appear above the erosional areas but rather between them. These normal faults are systematically located above locked patches and seismic asperities. These areas are actually at extensional critical state and characterized by a very low effective friction. We thus suspect the extensional features to be related to earthquakes rather than basal erosion. We then look for similar relationships along the Sumatra subduction zone to see if basal erosion is a common process. The Tocopilla and Iquique earthquakes ruptured only part of the northern Chile seismic gap although the full segment was ready for a new large

Global Positioning System data collection, processing, and analysis conducted by the U.S. Geological Survey Earthquake Hazards Program

USGS Publications Warehouse

Murray, Jessica R.; Svarc, Jerry L.

2017-01-01

The U.S. Geological Survey Earthquake Science Center collects and processes Global Positioning System (GPS) data throughout the western United States to measure crustal deformation related to earthquakes and tectonic processes as part of a long‐term program of research and monitoring. Here, we outline data collection procedures and present the GPS dataset built through repeated temporary deployments since 1992. This dataset consists of observations at ∼1950 locations. In addition, this article details our data processing and analysis procedures, which consist of the following. We process the raw data collected through temporary deployments, in addition to data from continuously operating western U.S. GPS stations operated by multiple agencies, using the GIPSY software package to obtain position time series. Subsequently, we align the positions to a common reference frame, determine the optimal parameters for a temporally correlated noise model, and apply this noise model when carrying out time‐series analysis to derive deformation measures, including constant interseismic velocities, coseismic offsets, and transient postseismic motion.

The California Hazards Institute

NASA Astrophysics Data System (ADS)

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

2006-12-01

California's abundant resources are linked with its natural hazards. Earthquakes, landslides, wildfires, floods, tsunamis, volcanic eruptions, severe storms, fires, and droughts afflict the state regularly. These events have the potential to become great disasters, like the San Francisco earthquake and fire of 1906, that overwhelm the capacity of society to respond. At such times, the fabric of civic life is frayed, political leadership is tested, economic losses can dwarf available resources, and full recovery can take decades. A patchwork of Federal, state and local programs are in place to address individual hazards, but California lacks effective coordination to forecast, prevent, prepare for, mitigate, respond to, and recover from, the harmful effects of natural disasters. Moreover, we do not know enough about the frequency, size, time, or locations where they may strike, nor about how the natural environment and man-made structures would respond. As California's population grows and becomes more interdependent, even moderate events have the potential to trigger catastrophes. Natural hazards need not become natural disasters if they are addressed proactively and effectively, rather than reactively. The University of California, with 10 campuses distributed across the state, has world-class faculty and students engaged in research and education in all fields of direct relevance to hazards. For that reason, the UC can become a world leader in anticipating and managing natural hazards in order to prevent loss of life and property and degradation of environmental quality. The University of California, Office of the President, has therefore established a new system-wide Multicampus Research Project, the California Hazards Institute (CHI), as a mechanism to research innovative, effective solutions for California. The CHI will build on the rich intellectual capital and expertise of the Golden State to provide the best available science, knowledge and tools for

California's Vulnerability to Volcanic Hazards: What's at Risk?

NASA Astrophysics Data System (ADS)

Mangan, M.; Wood, N. J.; Dinitz, L.

2015-12-01

California is a leader in comprehensive planning for devastating earthquakes, landslides, floods, and tsunamis. Far less attention, however, has focused on the potentially devastating impact of volcanic eruptions, despite the fact that they occur in the State about as frequently as the largest earthquakes on the San Andreas Fault Zone. At least 10 eruptions have occurred in the past 1,000 years—most recently in northern California (Lassen Peak 1914 to 1917)—and future volcanic eruptions are inevitable. The likelihood of renewed volcanism in California is about one in a few hundred to one in a few thousand annually. Eight young volcanoes, ranked as Moderate to Very High Threat [1] are dispersed throughout the State. Partially molten rock (magma) resides beneath at least seven of these—Medicine Lake Volcano, Mount Shasta, Lassen Volcanic Center, Clear Lake Volcanic Field, Long Valley Volcanic Region, Coso Volcanic Field, and Salton Buttes— causing earthquakes, toxic gas emissions, hydrothermal activity, and (or) ground deformation. Understanding the hazards and identifying what is at risk are the first steps in building community resilience to volcanic disasters. This study, prepared in collaboration with the State of California Governor's Office of Emergency Management and the California Geological Survey, provides a broad perspective on the State's exposure to volcano hazards by integrating mapped volcano hazard zones with geospatial data on at-risk populations, infrastructure, and resources. The study reveals that ~ 16 million acres fall within California's volcano hazard zones, along with ~ 190 thousand permanent and 22 million transitory populations. Additionally, far-field disruption to key water delivery systems, agriculture, utilities, and air traffic is likely. Further site- and sector-specific analyses will lead to improved hazard mitigation efforts and more effective disaster response and recovery. [1] "Volcanic Threat and Monitoring Capabilities

Apparent stress, fault maturity and seismic hazard for normal-fault earthquakes at subduction zones

USGS Publications Warehouse

Choy, G.L.; Kirby, S.H.

2004-01-01

The behavior of apparent stress for normal-fault earthquakes at subduction zones is derived by examining the apparent stress (?? a = ??Es/Mo, where E s is radiated energy and Mo is seismic moment) of all globally distributed shallow (depth, ?? 1 MPa) are also generally intraslab, but occur where the lithosphere has just begun subduction beneath the overriding plate. They usually occur in cold slabs near trenches where the direction of plate motion across the trench is oblique to the trench axis, or where there are local contortions or geometrical complexities of the plate boundary. Lower ??a (< 1 MPa) is associated with events occurring at the outer rise (OR) complex (between the OR and the trench axis), as well as with intracrustal events occurring just landward of the trench. The average apparent stress of intraslab-normal-fault earthquakes is considerably higher than the average apparent stress of interplate-thrust-fault earthquakes. In turn, the average ?? a of strike-slip earthquakes in intraoceanic environments is considerably higher than that of intraslab-normal-fault earthquakes. The variation of average ??a with focal mechanism and tectonic regime suggests that the level of ?? a is related to fault maturity. Lower stress drops are needed to rupture mature faults such as those found at plate interfaces that have been smoothed by large cumulative displacements (from hundreds to thousands of kilometres). In contrast, immature faults, such as those on which intraslab-normal-fault earthquakes generally occur, are found in cold and intact lithosphere in which total fault displacement has been much less (from hundreds of metres to a few kilometres). Also, faults on which high ??a oceanic strike-slip earthquakes occur are predominantly intraplate or at evolving ends of transforms. At subduction zones, earthquakes occurring on immature faults are likely to be more hazardous as they tend to generate higher amounts of radiated energy per unit of moment than

Assessing giant tsunamigenic subduction earthquakes in the Northern Chile Seismic Gap during the last two millennia

NASA Astrophysics Data System (ADS)

Vargas Easton, G.; Ruiz, S.; Leyton, F.; Abrahami, R.; Le Roux, J.; Pantoja, S.; Lange, C.; Contreras Reyes, E.; Campos, J. A.

2014-12-01

Marine sedimentary records off Northern Chile provide a new view about the occurrence of large subduction earthquakes along the hyperarid convergent margin of the Central Andes. From high resolution geochronology and sedimentology of laminated series accumulated on narrow shelf, we observed that anomalous structures such as slumps and discontinuities overlaid by turbidite deposits record the last giant Mw~8.8 earthquake and tsunami occurred on 1877 in the region. Once compared with the reanalysis of historical chronicles and seismological data, we suggest that only large magnitude events produce ground accelerations generating slumping or discontinuities. The analysis of long (ca. 5.5 m) sediment cores together with high resolution seismic subbottom profile data allow us to infer the occurrence of several giant earthquakes in the last ca. 1600 years, with a mean recurrence in the order of 400 years. Under this scope, the Mw8.1 occurred this year off Pisagua-Iquique region, as other previous historic events (Mw7.7, Tocopilla, 2007; Mw7.6, Iquique, 1933), seem to be moderate earthquakes into a larger seismic cycle.

Earthquake Loss Estimates in Near Real-Time

NASA Astrophysics Data System (ADS)

Wyss, Max; Wang, Rongjiang; Zschau, Jochen; Xia, Ye

2006-10-01

The usefulness to rescue teams of nearreal-time loss estimates after major earthquakes is advancing rapidly. The difference in the quality of data available in highly developed compared with developing countries dictates that different approaches be used to maximize mitigation efforts. In developed countries, extensive information from tax and insurance records, together with accurate census figures, furnish detailed data on the fragility of buildings and on the number of people at risk. For example, these data are exploited by the method to estimate losses used in the Hazards U.S. Multi-Hazard (HAZUSMH)software program (http://www.fema.gov/plan/prevent/hazus/). However, in developing countries, the population at risk is estimated from inferior data sources and the fragility of the building stock often is derived empirically, using past disastrous earthquakes for calibration [Wyss, 2004].

Probabilistic assessment of landslide tsunami hazard for the northern Gulf of Mexico

NASA Astrophysics Data System (ADS)

Pampell-Manis, A.; Horrillo, J.; Shigihara, Y.; Parambath, L.

2016-01-01

The devastating consequences of recent tsunamis affecting Indonesia and Japan have prompted a scientific response to better assess unexpected tsunami hazards. Although much uncertainty exists regarding the recurrence of large-scale tsunami events in the Gulf of Mexico (GoM), geological evidence indicates that a tsunami is possible and would most likely come from a submarine landslide triggered by an earthquake. This study customizes for the GoM a first-order probabilistic landslide tsunami hazard assessment. Monte Carlo Simulation (MCS) is employed to determine landslide configurations based on distributions obtained from observational submarine mass failure (SMF) data. Our MCS approach incorporates a Cholesky decomposition method for correlated landslide size parameters to capture correlations seen in the data as well as uncertainty inherent in these events. Slope stability analyses are performed using landslide and sediment properties and regional seismic loading to determine landslide configurations which fail and produce a tsunami. The probability of each tsunamigenic failure is calculated based on the joint probability of slope failure and probability of the triggering earthquake. We are thus able to estimate sizes and return periods for probabilistic maximum credible landslide scenarios. We find that the Cholesky decomposition approach generates landslide parameter distributions that retain the trends seen in observational data, improving the statistical validity and relevancy of the MCS technique in the context of landslide tsunami hazard assessment. Estimated return periods suggest that probabilistic maximum credible SMF events in the north and northwest GoM have a recurrence of 5000-8000 years, in agreement with age dates of observed deposits.

The seismic project of the National Tsunami Hazard Mitigation Program

USGS Publications Warehouse

Oppenheimer, D.H.; Bittenbinder, A.N.; Bogaert, B.M.; Buland, R.P.; Dietz, L.D.; Hansen, R.A.; Malone, S.D.; McCreery, C.S.; Sokolowski, T.J.; Whitmore, P.M.; Weaver, C.S.

2005-01-01

In 1997, the Federal Emergency Management Agency (FEMA), National Oceanic and Atmospheric Administration (NOAA), U.S. Geological Survey (USGS), and the five western States of Alaska, California, Hawaii, Oregon, and Washington joined in a partnership called the National Tsunami Hazard Mitigation Program (NTHMP) to enhance the quality and quantity of seismic data provided to the NOAA tsunami warning centers in Alaska and Hawaii. The NTHMP funded a seismic project that now provides the warning centers with real-time seismic data over dedicated communication links and the Internet from regional seismic networks monitoring earthquakes in the five western states, the U.S. National Seismic Network in Colorado, and from domestic and global seismic stations operated by other agencies. The goal of the project is to reduce the time needed to issue a tsunami warning by providing the warning centers with high-dynamic range, broadband waveforms in near real time. An additional goal is to reduce the likelihood of issuing false tsunami warnings by rapidly providing to the warning centers parametric information on earthquakes that could indicate their tsunamigenic potential, such as hypocenters, magnitudes, moment tensors, and shake distribution maps. New or upgraded field instrumentation was installed over a 5-year period at 53 seismic stations in the five western states. Data from these instruments has been integrated into the seismic network utilizing Earthworm software. This network has significantly reduced the time needed to respond to teleseismic and regional earthquakes. Notably, the West Coast/Alaska Tsunami Warning Center responded to the 28 February 2001 Mw 6.8 Nisqually earthquake beneath Olympia, Washington within 2 minutes compared to an average response time of over 10 minutes for the previous 18 years. ?? Springer 2005.

Statistical analysis of earthquakes after the 1999 MW 7.7 Chi-Chi, Taiwan, earthquake based on a modified Reasenberg-Jones model

NASA Astrophysics Data System (ADS)

Chen, Yuh-Ing; Huang, Chi-Shen; Liu, Jann-Yenq

2015-12-01

We investigated the temporal-spatial hazard of the earthquakes after the 1999 September 21 MW = 7.7 Chi-Chi shock in a continental region of Taiwan. The Reasenberg-Jones (RJ) model (Reasenberg and Jones, 1989, 1994) that combines the frequency-magnitude distribution (Gutenberg and Richter, 1944) and time-decaying occurrence rate (Utsu et al., 1995) is conventionally employed for assessing the earthquake hazard after a large shock. However, it is found that the b values in the frequency-magnitude distribution of the earthquakes in the study region dramatically decreased from background values after the Chi-Chi shock, and then gradually increased up. The observation of a time-dependent frequency-magnitude distribution motivated us to propose a modified RJ model (MRJ) to assess the earthquake hazard. To see how the models perform on assessing short-term earthquake hazard, the RJ and MRJ models were separately used to sequentially forecast earthquakes in the study region. To depict the potential rupture area for future earthquakes, we further constructed relative hazard (RH) maps based on the two models. The Receiver Operating Characteristics (ROC) curves (Swets, 1988) finally demonstrated that the RH map based on the MRJ model was, in general, superior to the one based on the original RJ model for exploring the spatial hazard of earthquakes in a short time after the Chi-Chi shock.

Report on the Aseismic Slip, Tremor, and Earthquakes Workshop

USGS Publications Warehouse

Gomberg, Joan; Roeloffs, Evelyn; Trehu, Anne; Dragert, Herb; Meertens, Charles

2008-01-01

This report summarizes the discussions and information presented during the workshop on Aseismic Slip, Tremor, and Earthquakes. Workshop goals included improving coordination among those involved in conducting research related to these phenomena, assessing the implications for earthquake hazard assessment, and identifying ways to capitalize on the education and outreach opportunities presented by these phenomena. Research activities of focus included making, disseminating, and analyzing relevant measurements; the relationships among tremor, aseismic or 'slow-slip', and earthquakes; and discovering the underlying causative physical processes. More than 52 participants contributed to the workshop, held February 25-28, 2008 in Sidney, British Columbia. The workshop was sponsored by the U.S. Geological Survey, the National Science Foundation?s Earthscope Program and UNAVCO Consortium, and the Geological Survey of Canada. This report has five parts. In the first part, we integrate the information exchanged at the workshop as it relates to advancing our understanding of earthquake generation and hazard. In the second part, we summarize the ideas and concerns discussed in workshop working groups on Opportunities for Education and Outreach, Data and Instrumentation, User and Public Needs, and Research Coordination. The third part presents summaries of the oral presentations. The oral presentations are grouped as they were at the workshop in the categories of phenomenology, underlying physical processes, and implications for earthquake hazards. The fourth part contains the meeting program and the fifth part lists the workshop participants. References noted in parentheses refer to the authors of presentations made at the workshop, and published references are noted in square brackets and listed in the Reference section. Appendix A contains abstracts of all participant presentations and posters, which also have been posted online, along with presentations and author contact

The 1868 Hayward Earthquake Alliance: A Case Study - Using an Earthquake Anniversary to Promote Earthquake Preparedness

NASA Astrophysics Data System (ADS)

Brocher, T. M.; Garcia, S.; Aagaard, B. T.; Boatwright, J. J.; Dawson, T.; Hellweg, M.; Knudsen, K. L.; Perkins, J.; Schwartz, D. P.; Stoffer, P. W.; Zoback, M.

2008-12-01

Last October 21st marked the 140th anniversary of the M6.8 1868 Hayward Earthquake, the last damaging earthquake on the southern Hayward Fault. This anniversary was used to help publicize the seismic hazards associated with the fault because: (1) the past five such earthquakes on the Hayward Fault occurred about 140 years apart on average, and (2) the Hayward-Rodgers Creek Fault system is the most likely (with a 31 percent probability) fault in the Bay Area to produce a M6.7 or greater earthquake in the next 30 years. To promote earthquake awareness and preparedness, over 140 public and private agencies and companies and many individual joined the public-private nonprofit 1868 Hayward Earthquake Alliance (1868alliance.org). The Alliance sponsored many activities including a public commemoration at Mission San Jose in Fremont, which survived the 1868 earthquake. This event was followed by an earthquake drill at Bay Area schools involving more than 70,000 students. The anniversary prompted the Silver Sentinel, an earthquake response exercise based on the scenario of an earthquake on the Hayward Fault conducted by Bay Area County Offices of Emergency Services. 60 other public and private agencies also participated in this exercise. The California Seismic Safety Commission and KPIX (CBS affiliate) produced professional videos designed forschool classrooms promoting Drop, Cover, and Hold On. Starting in October 2007, the Alliance and the U.S. Geological Survey held a sequence of press conferences to announce the release of new research on the Hayward Fault as well as new loss estimates for a Hayward Fault earthquake. These included: (1) a ShakeMap for the 1868 Hayward earthquake, (2) a report by the U. S. Bureau of Labor Statistics forecasting the number of employees, employers, and wages predicted to be within areas most strongly shaken by a Hayward Fault earthquake, (3) new estimates of the losses associated with a Hayward Fault earthquake, (4) new ground motion

Earthquakes, July-August 1991

USGS Publications Warehouse

Person, W.J.

1992-01-01

There was one major earthquake during this reporting period-a magnitude 7.1 shock off the coast of Northern California on August 17. Earthquake-related deaths were reported from Indonesia, Romania, Peru, and Iraq. 

Earthquake Forecasting System in Italy

NASA Astrophysics Data System (ADS)

Falcone, G.; Marzocchi, W.; Murru, M.; Taroni, M.; Faenza, L.

2017-12-01

In Italy, after the 2009 L'Aquila earthquake, a procedure was developed for gathering and disseminating authoritative information about the time dependence of seismic hazard to help communities prepare for a potentially destructive earthquake. The most striking time dependency of the earthquake occurrence process is the time clustering, which is particularly pronounced in time windows of days and weeks. The Operational Earthquake Forecasting (OEF) system that is developed at the Seismic Hazard Center (Centro di Pericolosità Sismica, CPS) of the Istituto Nazionale di Geofisica e Vulcanologia (INGV) is the authoritative source of seismic hazard information for Italian Civil Protection. The philosophy of the system rests on a few basic concepts: transparency, reproducibility, and testability. In particular, the transparent, reproducible, and testable earthquake forecasting system developed at CPS is based on ensemble modeling and on a rigorous testing phase. Such phase is carried out according to the guidance proposed by the Collaboratory for the Study of Earthquake Predictability (CSEP, international infrastructure aimed at evaluating quantitatively earthquake prediction and forecast models through purely prospective and reproducible experiments). In the OEF system, the two most popular short-term models were used: the Epidemic-Type Aftershock Sequences (ETAS) and the Short-Term Earthquake Probabilities (STEP). Here, we report the results from OEF's 24hour earthquake forecasting during the main phases of the 2016-2017 sequence occurred in Central Apennines (Italy).

Earthquake stress triggers, stress shadows, and seismic hazard

USGS Publications Warehouse

Harris, R.A.

2000-01-01

Many aspects of earthquake mechanics remain an enigma at the beginning of the twenty-first century. One potential bright spot is the realization that simple calculations of stress changes may explain some earthquake interactions, just as previous and ongoing studies of stress changes have begun to explain human- induced seismicity. This paper, which is an update of Harris1, reviews many published works and presents a compilation of quantitative earthquake-interaction studies from a stress change perspective. This synthesis supplies some clues about certain aspects of earthquake mechanics. It also demonstrates that much work remains to be done before we have a complete story of how earthquakes work.

Evansville Area Earthquake Hazards Mapping Project (EAEHMP) - Progress Report, 2008