Regional Differences in the Psychological Recovery of Christchurch Residents Following the 2010/2011 Earthquakes: A Longitudinal Study

PubMed Central

Greaves, Lara M.; Milojev, Petar; Huang, Yanshu; Stronge, Samantha; Osborne, Danny; Bulbulia, Joseph; Grimshaw, Michael; Sibley, Chris G.

2015-01-01

We examined changes in psychological distress experienced by residents of Christchurch following two catastrophic earthquakes in late 2010 and early 2011, using data from the New Zealand Attitudes and Values Study (NZAVS), a national probability panel study of New Zealand adults. Analyses focused on the 267 participants (172 women, 95 men) who were living in central Christchurch in 2009 (i.e., before the Christchurch earthquakes), and who also provided complete responses to our yearly panel questionnaire conducted in late 2010 (largely between the two major earthquakes), late 2011, and late 2012. Levels of psychological distress were similar across the different regions of central Christchurch immediately following the September 2010 earthquake, and remained comparable across regions in 2011. By late 2012, however, average levels of psychological distress in the regions had diverged as a function of the amount of property damage experienced within each given region. Specifically, participants in the least damaged region (i.e., the Fendalton-Waimairi and Riccarton-Wigram wards) experienced greater drops in psychological distress than did those in the moderately damaged region (i.e., across the Spreydon-Heathcote and Hagley-Ferrymead wards). However, the level of psychological distress reported by participants in the most damaged region (i.e., across Shirley-Papanui and Burwood-Pegasus) were not significantly different to those in the least damaged region of central Christchurch. These findings suggest that different patterns of psychological recovery emerged across the different regions of Christchurch, with the moderately damaged region faring the worst, but only after the initial shock of the destruction had passed. PMID:25932919

Analysis of frequency shifting in seismic signals using Gabor-Wigner transform

NASA Astrophysics Data System (ADS)

Kumar, Roshan; Sumathi, P.; Kumar, Ashok

2015-12-01

A hybrid time-frequency method known as Gabor-Wigner transform (GWT) is introduced in this paper for examining the time-frequency patterns of earthquake damaged buildings. GWT is developed by combining the Gabor transform (GT) and Wigner-Ville distribution (WVD). GT and WVD have been used separately on synthetic and recorded earthquake data to identify frequency shifting due to earthquake damages, but GT is prone to windowing effect and WVD involves ambiguity function. Hence to obtain better clarity and to remove the cross terms (frequency interference), GT and WVD are judiciously combined and the resultant GWT used to identify frequency shifting. Synthetic seismic response of an instrumented building and real-time earthquake data recorded on the building were investigated using GWT. It is found that GWT offers good accuracy for even slow variations in frequency, good time-frequency resolution, and localized response. Presented results confirm the efficacy of GWT when compared with GT and WVD used separately. Simulation results were quantified by the Renyi entropy measures and GWT shown to be an adequate technique in identifying localized response for structural damage detection.

Damage and Shaking Intensity in the M5.7 Canyondam Earthquake

NASA Astrophysics Data System (ADS)

Boatwright, J.; Chapman, K.; Gold, M. B.; Hardebeck, J. L.

2013-12-01

An M5.7 earthquake occurred southeast of Lake Almanor, CA, at 8:47 PM on May 23, 2013. Double-difference relocations of the main shock and aftershocks indicate that the earthquake nucleated at 11 km depth and ruptured up dip on a fault striking 292° and dipping 70° to the northeast. The earthquake cracked foundations, broke chimneys, and ruptured plumbing around Lake Almanor. We canvassed communities around the lake and to the south and east for earthquake damage, adding reports from our interviews to the geocoded 'Did You Feel It?' reports and to a set of damage reports collected by the Plumas County Office of Emergency Services. Three communities suffered significant damage. In Lake Almanor West, 14 km and 290° from the hypocenter, one wood-frame house was shifted on its foundation, the cripple wall of another house was racked, and water and gas pipes in five houses were ruptured. This damage indicates the shaking approached MMI 8. In Lake Almanor Country Club, 10 km and 310° from the hypocenter, more than 40 chimneys were cracked, broken, or collapsed, a coupling for the municipal water tank was ruptured, and a 200-foot long fissure opened on a slope facing the lake. This damage indicates shaking between MMI 7 and MMI 8, consistent with the accelerograph recording of PGA = 38% g and PGV = 30 cm/s at the Fire Station in Lake Almanor Country Club. This CSMIP station and a PG&E station on the crest of the Butt Valley Dam obtained the only recordings within 50 km of the epicenter. In Hamilton Branch, 10 km and 345° from the hypocenter, a foundation of a wood-frame house was damaged, and 14 chimneys and a water pipe were broken, indicative of MMI 7 shaking. All three communities are underlain by Tertiary and Quaternary basalts. The communities of Chester, Westwood, and Greenville were less damaged, suffering cracked drywall, broken windows, and objects thrown from shelves. The intensities in the three most strongly damaged communities increase as the azimuth from the source approaches the fault strike. This damage pattern could be caused by rupture directivity if the earthquake or the strongest sub-event of the earthquake ruptured up dip and to the west.

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

NASA Astrophysics Data System (ADS)

Hutchinson, Lauren; Stead, Doug; Rosser, Nick

2017-04-01

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

Modelling Pre-eruptive Progressive Damage in Basaltic Volcanoes: Consequences for the Pre-eruptive Process

NASA Astrophysics Data System (ADS)

Got, J. L.; Amitrano, D.; Carrier, A.; Marsan, D.; Jouanne, F.; Vogfjord, K. S.

2017-12-01

At Grimsvötn volcano, high-quality earthquake and continuous GPS data were recorded by the Icelandic Meteorological Office during its 2004-2011 inter-eruptive period and exhibited remarkable patterns : acceleration of the cumulated earthquake number, and a 2-year exponential decrease in displacement rate followed by a 4-year constant inflation rate. We proposed a model with one magma reservoir in a non-linear elastic damaging edifice, with incompressible magma and a constant pressure at the base of the magma conduit. We first modelled seismicity rate and damage as a function of time, and show that Kachanov's elastic brittle damage law may be used to express the decrease of the effective shear modulus with time. We then derived simple analytical expressions for the magma reservoir overpressure and the surface displacement as a function of time. We got a very good fit of the seismicity and surface displacement data by adjusting only three phenomenological parameters and computed magma reservoir overpressure, magma flow and strain power as a function of time. Overpressure decrease is controlled by damage and shear modulus decrease. Displacement increases, although overpressure is decreasing, because shear modulus decreases more than overpressure. Normalized strain power reaches a maximum 0.25 value. This maximum is a physical limit, after which the elasticity laws are no longer valid, earthquakes cluster, cumulative number of earthquakes departs from the model. State variable extrema provide four reference times that may be used to assess the mechanical state and dynamics of the volcanic edifice. We also performed the spatial modelling of the progressive damage and strain localization around a pressurized magma reservoir. We used Kachanov's damage law and finite element modelling of an initially elastic volcanic edifice pressurized by a spherical magma reservoir, with a constant pressure in the reservoir and various external boundary conditions. At each node of the model, Young's modulus is decreased if deviatoric stress locally reaches the Mohr-Coulomb plastic threshold. For a compressive horizontal stress, the result shows a complex strain localization pattern, showing reverse and normal faulting very similar to what is obtained from analog modelling and observed at volcanic resurgent domes.

Strong ground motion prediction using virtual earthquakes.

PubMed

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

2014-01-24

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

Remotely-triggered Slip in Mexico City Induced by the September 2017 Mw=7.1 Puebla Earthquake.

NASA Astrophysics Data System (ADS)

Solano Rojas, D. E.; Havazli, E.; Cabral-Cano, E.; Wdowinski, S.

2017-12-01

Although the epicenter of the September 19th, 2017 Mw=7.1 Puebla earthquake is located 100 km from Mexico City, the earthquake caused severe destruction in the city, leading to life loss and property damage. Mexico City is built on a thick clay-rich sedimentary sequence and, hence, is susceptible to seismic acceleration during earthquakes. The sediment layer also causes land subsidence, at rates as high as 350 mm/yr, and surface faulting. The earthquake damage in the eastern part of the city, characterized by the collapse of several buildings, can be explained by seismic amplification. However, the damage in the southern part of the city, characterized by the collapse of small houses and surface faulting, requires a different explanation. We present here geodetic observations suggesting that the surface faulting in Mexico City triggered by the Puebla earthquake occurred in areas already experiencing differential displacements. Our study is based on Sentinel-1A satellite data from before and after the earthquake (September 17th and 29th, 2017). We process the data using Interferometric Synthetic Aperture Radar (InSAR) to produce a coseismic interferogram. We also identify phase discontinuities that can be interpreted as surface faulting using the phase gradient technique (Price and Sandwell, 1998). The results of our analysis reveal the locations and patterns of coseismic phase discontinuities, mainly in the piedmont of the Sierra de Santa Catarina, which agree with the location of earthquake's damage reported by official and unofficial sources (GCDMX, 2017; OSM, 2017). The observed phase discontinuities also agree well with the location of preexisting, subsidence-related faults identified during 10 years of field surveys (GCDMX, 2017) and coincide with differential displacements identified using a Fast Fourier Transform residual technique on high-resolution InSAR results from 2012 (Solano-Rojas et. al, 2017). We propose that the seismic energy released by the 2017 Mw=7.1 Puebla earthquake induced fast soil consolidation, which remotely triggered slip on the preexisting subsidence-related faults. The slip observed during this earthquake represents a hazard that needs to be considered in future urban development plans of Mexico City.

ANALYSIS FOR HOUSE DAMAGE PROPERTY OF 2007 MID-NIIGATA PREFECTURE OFFSHORE EARTHQUAKE

NASA Astrophysics Data System (ADS)

Ochiai, Hirokazu; Yamada, Kento; Ohtsuka, Satoru; Isobe, Koichi

This paper reports the result of correlation analysis for house damage in 2007 Mid-piigata prefecture offshore earthquake by focusing geomorphological land classification and other factors as landform and ground properties with organizing the house damage data of disaster victim certificate conducted by public administrations. In former part of the paper, the features of house damage at 2007 Mid-Niigata prefecture offshore earthquake were analyzed for various influencing factors. The authors discussed the affrecting factors to houses at earthquake. In latter part, the features of house damage at 2007 Mid-Niigata prefecture offshore earthquake was discussed with that at 2004 Mid-Niigata prefecture earthquake. The house damage function of distance from the epicenter was proposed based on the analysis on house damage ratio recorded in two earthquakes.

Tiny intraplate earthquakes triggered by nearby episodic tremor and slip in Cascadia

USGS Publications Warehouse

Vidale, J.E.; Hotovec, A.J.; Ghosh, A.; Creager, K.C.; Gomberg, J.

2011-01-01

Episodic tremor and slip (ETS) has been observed in many subduction zones, but its mechanical underpinnings as well as its potential for triggering damaging earthquakes have proven difficult to assess. Here we use a seismic array in Cascadia of unprecedented density to monitor seismicity around a moderate 16 day ETS episode. In the 4 months of data we examine, we observe five tiny earthquakes within the subducting slab during the episode and only one more in the same area, which was just before and nearby the next ETS burst. These earthquakes concentrate along the sides and updip edge of the ETS region, consistent with greater stress concentration there than near the middle and downdip edge of the tremor area. Most of the seismicity is below the megathrust, with a similar depth extent to the background intraslab seismicity. The pattern of earthquakes that we find suggests slow slip has a more continuous temporal and spatial pattern than the tremor loci, which notoriously appear in bursts, jumps, and streaks. Copyright 2011 by the American Geophysical Union.

Nonlinear analyses and failure patterns of typical masonry school buildings in the epicentral zone of the 2016 Italian earthquakes

NASA Astrophysics Data System (ADS)

Clementi, Cristhian; Clementi, Francesco; Lenci, Stefano

2017-11-01

The paper discusses the behavior of typical masonry school buildings in the center of Italy built at the end of 1950s without any seismic guidelines. These structures have faced the recent Italian earthquakes in 2016 without diffuse damages. Global numerical models of the building have been built and masonry material has been simulated as nonlinear. Sensitivity analyses are done to evaluate the reliability of the structural models.

Aftershock seismicity and Tectonic Setting of the 16 September 2015 Mw 8.3 Illapel earthquake

NASA Astrophysics Data System (ADS)

Lange, Dietrich; Geersen, Jacob; Barrientos, Sergio; Moreno, Marcos; Grevemeyer, Ingo; Contreras-Reyes, Eduardo; Kopp, Heidrun

2016-04-01

Powerful subduction zone earthquakes rupture thousands of square kilometers along continental margins but at certain locations earthquake rupture terminates. On 16 September 2015 the Mw. 8.3 Illapel earthquake ruptured a 200 km long stretch of the Central Chilean subduction zone, triggering a tsunami and causing significant damage. Here we analyze the spatial pattern of coseismic rupture and the temporal and spatial pattern of local seismicity for aftershocks and foreshocks in relation to the tectonic setting in the earthquake area. Aftershock seismicity surrounds the rupture area in lateral and downdip direction. For the first 24 hours following the mainshock we observe aftershock migration to both lateral directions with velocities of approximately 2.5 and 5 km/h. At the southern earthquake boundary aftershocks cluster around individual subducted seamounts located on the prolongation of the downthrusting Juan Fernández Ridge indicating stress transfer from the main rupture area. In the northern part of the rupture area a deeper band of local seismicity is observed indicating an alternation of seismic to aseismic behavior of the plate interface in downdip direction. This aseismic region at ~30 km depth that is also observed before the Illapel 2015 earthquake is likely controlled by the intersection of the continental Moho with the subducting slab.

The Loma Prieta, California, Earthquake of October 17, 1989: Strong Ground Motion and Ground Failure

USGS Publications Warehouse

Coordinated by Holzer, Thomas L.

1992-01-01

Professional Paper 1551 describes the effects at the land surface caused by the Loma Prieta earthquake. These effects: include the pattern and characteristics of strong ground shaking, liquefaction of both floodplain deposits along the Pajaro and Salinas Rivers in the Monterey Bay region and sandy artificial fills along the margins of San Francisco Bay, landslides in the epicentral region, and increased stream flow. Some significant findings and their impacts were: * Strong shaking that was amplified by a factor of about two by soft soils caused damage at up to 100 kilometers (60 miles) from the epicenter. * Instrumental recordings of the ground shaking have been used to improve how building codes consider site amplification effects from soft soils. * Liquefaction at 134 locations caused $99.2 million of the total earthquake loss of $5.9 billion. Liquefaction of floodplain deposits and sandy artificial fills was similar in nature to that which occurred in the 1906 San Francisco earthquake and indicated that many areas remain susceptible to liquefaction damage in the San Francisco and Monterey Bay regions. * Landslides caused $30 million in earthquake losses, damaging at least 200 residences. Many landslides showed evidence of movement in previous earthquakes. * Recognition of the similarities between liquefaction and landslides in 1906 and 1989 and research in intervening years that established methodologies to map liquefaction and landslide hazards prompted the California legislature to pass in 1990 the Seismic Hazards Mapping Act that required the California Geological Survey to delineate regulatory zones of areas potentially susceptible to these hazards. * The earthquake caused the flow of many streams in the epicentral region to increase. Effects were noted up to 88 km from the epicenter. * Post-earthquake studies of the Marina District of San Francisco provide perhaps the most comprehensive case history of earthquake effects at a specific site developed for any earthquake. Soft soils beneath the Marina amplified ground shaking to damaging levels and caused liquefaction of sandy artificial fills. Liquefaction required 123 repairs of pipelines in the Municipal Water Supply System, more than three times the number of repairs elsewhere in the system. Approximately 13.6 km of gas-distribution lines were replaced, and more than 20% of the wastewater collection lines were repaired or replaced.

Winnetka deformation zone: Surface expression of coactive slip on a blind fault during the Northridge earthquake sequence, California. Evidence that coactive faulting occurred in the Canoga Park, Winnetka, and Northridge areas during the 17 January 1994, Northridge, California earthquake

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

Cruikshank, K.M.; Johnson, A.M.; Fleming, R.W.

1996-12-31

Measurements of normalized length changes of streets over an area of 9 km{sup 2} in San Fernando Valley of Los Angeles, California, define a distinctive strain pattern that may well reflect blind faulting during the 1994 Northridge earthquake. Strain magnitudes are about 3 {times} 10{sup {minus}4}, locally 10{sup {minus}3}. They define a deformation zone trending diagonally from near Canoga Park in the southwest, through Winnetka, to near Northridge in the northeast. The deformation zone is about 4.5 km long and 1 km wide. The northwestern two-thirds of the zone is a belt of extension of streets, and the southeastern one-thirdmore » is a belt of shortening of streets. On the northwest and southeast sides of the deformation zone the magnitude of the strains is too small to measure, less than 10{sup {minus}4}. Complete states of strain measured in the northeastern half of the deformation zone show that the directions of principal strains are parallel and normal to the walls of the zone, so the zone is not a strike-slip zone. The magnitudes of strains measured in the northeastern part of the Winnetka area were large enough to fracture concrete and soils, and the area of larger strains correlates with the area of greater damage to such roads and sidewalks. All parts of the pattern suggest a blind fault at depth, most likely a reverse fault dipping northwest but possibly a normal fault dipping southeast. The magnitudes of the strains in the Winnetka area are consistent with the strains produced at the ground surface by a blind fault plane extending to depth on the order of 2 km and a net slip on the order of 1 m, within a distance of about 100 to 500 m of the ground surface. The pattern of damage in the San Fernando Valley suggests a fault segment much longer than the 4.5 km defined by survey data in the Winnetka area. The blind fault segment may extend several kilometers in both directions beyond the Winnetka area. This study of the Winnetka area further supports observations that a large earthquake sequence can include rupture along both a main fault and nearby faults with quite different senses of slip. Faults near the main fault that approach the ground surface or cut the surface in an area have the potential of moving coactively in a major earthquake. Movement on such faults is associated with significant damage during an earthquake. The fault that produced the main Northridge shock and the faults that moved coactively in the Northridge area probably are parts of a large structure. Such interrelationships may be key to understanding earthquakes and damage caused by tectonism.« less

Damages from the 20 September earthquakes near Klamath Falls, Oregon

USGS Publications Warehouse

Dewey, J.W.

1993-01-01

Most of the damage resulting from the earthquakes was reported from Klamath Falls, approximately 20 km from the source region of earthquakes. As has commonly been the case with earthquakes in other parts of the United States, the degree of damage was highly uneven in Klamath Falls. Most of the town escaped with little damage to buildings or building contents. Losses were concentrated in the downtown area, but even there most of the buildings were not damaged. The unevenness of damage in earthquakes results primarily from large differences in the seismic resistance of individual buildings and differences in the seismic response due to different soil conditions and geology beneath buildings. 

Earthquakes in the Central United States, 1699-2010

USGS Publications Warehouse

Dart, Richard L.; Volpi, Christina M.

2010-01-01

This publication is an update of an earlier report, U.S. Geological Survey (USGS) Geologic Investigation I-2812 by Wheeler and others (2003), titled ?Earthquakes in the Central United States-1699-2002.? Like the original poster, the center of the updated poster is a map showing the pattern of earthquake locations in the most seismically active part of the central United States. Arrayed around the map are short explanatory texts and graphics, which describe the distribution of historical earthquakes and the effects of the most notable of them. The updated poster contains additional, post 2002, earthquake data. These are 38 earthquakes covering the time interval from January 2003 to June 2010, including the Mount Carmel, Illinois, earthquake of 2008. The USGS Preliminary Determination of Epicenters (PDE) was the source of these additional data. Like the I-2812 poster, this poster was prepared for a nontechnical audience and designed to inform the general public as to the widespread occurrence of felt and damaging earthquakes in the Central United States. Accordingly, the poster should not be used to assess earthquake hazard in small areas or at individual locations.

Damaging earthquakes: A scientific laboratory

USGS Publications Warehouse

Hays, Walter W.; ,

1996-01-01

This paper reviews the principal lessons learned from multidisciplinary postearthquake investigations of damaging earthquakes throughout the world during the past 15 years. The unique laboratory provided by a damaging earthquake in culturally different but tectonically similar regions of the world has increased fundamental understanding of earthquake processes, added perishable scientific, technical, and socioeconomic data to the knowledge base, and led to changes in public policies and professional practices for earthquake loss reduction.

Earthquakes; January-February, 1979

USGS Publications Warehouse

Person, W.J.

1979-01-01

The first major earthquake (magnitude 7.0 to 7.9) of the year struck in southeastern Alaska in a sparsely populated area on February 28. On January 16, Iran experienced the first destructive earthquake of the year causing a number of casualties and considerable damage. Peru was hit by a destructive earthquake on February 16 that left casualties and damage. A number of earthquakes were experienced in parts of the Untied States, but only minor damage was reported. 

Earthquakes; January-February 1982

USGS Publications Warehouse

Person, W.J.

1982-01-01

In the United States, a number of earthquakes occurred, but only minor damage was reported. Arkansas experienced a swarm of earthquakes beginning on January 12. Canada experienced one of its strongest earthquakes in a number of years on January 9; this earthquake caused slight damage in Maine. 

The quest for better quality-of-life - learning from large-scale shaking table tests

NASA Astrophysics Data System (ADS)

Nakashima, M.; Sato, E.; Nagae, T.; Kunio, F.; Takahito, I.

2010-12-01

Earthquake engineering has its origins in the practice of “learning from actual earthquakes and earthquake damages.” That is, we recognize serious problems by witnessing the actual damage to our structures, and then we develop and apply engineering solutions to solve these problems. This tradition in earthquake engineering, i.e., “learning from actual damage,” was an obvious engineering response to earthquakes and arose naturally as a practice in a civil and building engineering discipline that traditionally places more emphasis on experience than do other engineering disciplines. But with the rapid progress of urbanization, as society becomes denser, and as the many components that form our society interact with increasing complexity, the potential damage with which earthquakes threaten the society also increases. In such an era, the approach of ”learning from actual earthquake damages” becomes unacceptably dangerous and expensive. Among the practical alternatives to the old practice is to “learn from quasi-actual earthquake damages.” One tool for experiencing earthquake damages without attendant catastrophe is the large shaking table. E-Defense, the largest one we have, was developed in Japan after the 1995 Hyogoken-Nanbu (Kobe) earthquake. Since its inauguration in 2005, E-Defense has conducted over forty full-scale or large-scale shaking table tests, applied to a variety of structural systems. The tests supply detailed data on actual behavior and collapse of the tested structures, offering the earthquake engineering community opportunities to experience and assess the actual seismic performance of the structures, and to help society prepare for earthquakes. Notably, the data were obtained without having to wait for the aftermaths of actual earthquakes. Earthquake engineering has always been about life safety, but in recent years maintaining the quality of life has also become a critical issue. Quality-of-life concerns include nonstructural damage, business continuity, public health, quickness of damage assessment, infrastructure, data and communication networks, and other issues, and not enough useful empirical data have emerged about these issues from the experiences of actual earthquakes. To provide quantitative data that can be used to reduce earthquake risk to our quality of life, E-Defense recently has been implementing two comprehensive research projects in which a base-isolated hospital and a steel high-rise building were tested using the E-Defense shaking table and their seismic performance were examined particularly in terms of the nonstructural damage, damage to building contents and furniture, and operability, functionality, and business-continuity capability. The paper presents the overview of the two projects, together with major findings obtained from the projects.

Kinds of damage that could result from a great earthquake in the central United States

USGS Publications Warehouse

Hooper, M.G.; Algermissen, S.T.

1985-01-01

The first four photographs show damage caused by intensity VIII and above. None of the damage shown in the photographs in this report occurred in earthquakes larger than the 1811-12 New Madrid shocks, and most of the examples are from considerably smaller shocks. The first two photos show damage to masonry buildings, mostly old and unreinforced, none designed to be earthquake resistant. How many such buildings are in use in your community? The second pair of photos show damage to modern structures close to the epicenter of a magnitude 6.5 earthquake, a small shock compared to the magnitudes (8.4-8.7) of the New Madrid earthquakes. 

Earthquakes, May-June 1981

USGS Publications Warehouse

Person, W.J.

1981-01-01

The months of May and June were somewhat quiet, seismically speaking. There was one major earthquake (7.0-7.9) off the west coast of South Island, New Zealand. The most destructive earthquake during this reporting period was in southern Iran on June 11 which caused fatalities and extensive damage. Peru also experienced a destructive earthquake on June 22 which caused fatalities and damage. In the United States, a number of earthquakes were experienced, but none caused significant damage. 

Building Damage Extraction Triggered by Earthquake Using the Uav Imagery

NASA Astrophysics Data System (ADS)

Li, S.; Tang, H.

2018-04-01

When extracting building damage information, we can only determine whether the building is collapsed using the post-earthquake satellite images. Even the satellite images have the sub-meter resolution, the identification of slightly damaged buildings is still a challenge. As the complementary data to satellite images, the UAV images have unique advantages, such as stronger flexibility and higher resolution. In this paper, according to the spectral feature of UAV images and the morphological feature of the reconstructed point clouds, the building damage was classified into four levels: basically intact buildings, slightly damaged buildings, partially collapsed buildings and totally collapsed buildings, and give the rules of damage grades. In particular, the slightly damaged buildings are determined using the detected roof-holes. In order to verify the approach, we conduct experimental simulations in the cases of Wenchuan and Ya'an earthquakes. By analyzing the post-earthquake UAV images of the two earthquakes, the building damage was classified into four levels, and the quantitative statistics of the damaged buildings is given in the experiments.

Source characterization and dynamic fault modeling of induced seismicity

NASA Astrophysics Data System (ADS)

Lui, S. K. Y.; Young, R. P.

2017-12-01

In recent years there are increasing concerns worldwide that industrial activities in the sub-surface can cause or trigger damaging earthquakes. In order to effectively mitigate the damaging effects of induced seismicity, the key is to better understand the source physics of induced earthquakes, which still remain elusive at present. Furthermore, an improved understanding of induced earthquake physics is pivotal to assess large-magnitude earthquake triggering. A better quantification of the possible causes of induced earthquakes can be achieved through numerical simulations. The fault model used in this study is governed by the empirically-derived rate-and-state friction laws, featuring a velocity-weakening (VW) patch embedded into a large velocity-strengthening (VS) region. Outside of that, the fault is slipping at the background loading rate. The model is fully dynamic, with all wave effects resolved, and is able to resolve spontaneous long-term slip history on a fault segment at all stages of seismic cycles. An earlier study using this model has established that aseismic slip plays a major role in the triggering of small repeating earthquakes. This study presents a series of cases with earthquakes occurring on faults with different fault frictional properties and fluid-induced stress perturbations. The effects to both the overall seismicity rate and fault slip behavior are investigated, and the causal relationship between the pre-slip pattern prior to the event and the induced source characteristics is discussed. Based on simulation results, the subsequent step is to select specific cases for laboratory experiments which allow well controlled variables and fault parameters. Ultimately, the aim is to provide better constraints on important parameters for induced earthquakes based on numerical modeling and laboratory data, and hence to contribute to a physics-based induced earthquake hazard assessment.

Earthquakes, May-June 1991

USGS Publications Warehouse

Person, W.J.

1992-01-01

In the United States, a magnitude 5.8 earthquake in southern California on June 28 killed two people and caused considerable damage. Strong earthquakes hit Alaska on May 1 and May 30; the May 1 earthquake caused some minor damage. 

Orientation damage in the Christchurch cemeteries generated during the Christchurch earthquakes of 2010

NASA Astrophysics Data System (ADS)

Martín-González, Fidel; Perez-Lopez, Raul; Rodrigez-Pascua, Miguel Angel; Martin-Velazquez, Silvia

2014-05-01

The intensity scales determined the damage caused by an earthquake. However, a new methodology takes into account not only the damage but the type of damage "Earthquake Archaeological Effects" EAE's, and its orientation (e.g. displaced masonry blocks, impact marks, conjugated fractures, fallen and oriented columns, dipping broken corners, etc.). It focuses not only on the amount of damage but also in its orientation, giving information about the ground motion during the earthquake. In 2010 an earthquake of magnitude 6.2 took place in Christchurch (New Zealand) (22-2-2010), 185 casualties, making it the second-deadliest natural disaster in New Zealand. Due to the magnitude of the catastrophe, the city centre (CBD) was closed and the most damaged buildings were closed and later demolished. For this reason it could not be possible to access to sampling or make observations in the most damaged areas. However, the cemeteries were not closed and a year later still remained intact since the financial means to recover were used to reconstruct infrastructures and housing the city. This peculiarity of the cemeteries made measures of the earthquake effects possible. Orientation damage was measured on the tombs, crosses and headstones of the cemeteries (mainly on falling objects such as fallen crosses, obelisks, displaced tombstones, etc.). 140 data were taken in the most important cemeteries (Barbadoes, Addington, Pebleton, Woodston, Broomley and Linwood cemeteries) covering much of the city area. The procedure involved two main phases: a) inventory and identification of damages, and b) analysis of the damage orientations. The orientation was calculated for each element and plotted in a map and statistically in rose diagrams. The orientation dispersion is high in some cemeteries but damage orientation S-N and E-W is observed. However, due to the multiple seismogenic faults responsible for earthquakes and damages in Christchurch during the year after the 2010 earthquake, a more detailed correlation of the ground acceleration and the damages is being carried out. The orientation of the damage is not usually recorded after an earthquake; however, it can provide information on the orientation of the peak ground acceleration. Thus, when an earthquake occurs, the analysis of the damage orientation can provide information about the seismic source.

The characteristic of the earthquake damage in Kyoto during the historical period

NASA Astrophysics Data System (ADS)

Nishiyama, Akihito

2017-04-01

The Kyoto city is located in the northern part of the Kyoto basin, central Japan and has a history of more than 1200 years. Kyoto has long been populated area with many buildings, and the center of politics, economics and culture of Japan. Due to historical large earthquakes, the Kyoto city was severely damaged such as collapses of buildings and human casualties. In the historical period, the Kyoto city has experienced six damaging large earthquake of 976, 1185, 1449, 1596, 1662 and 1830. Among them, Kyoto has experienced three damaging large earthquakes from the end of the 16th century to the middle of the 19th century, when the urban area was being expanded. All of these earthquakes are considered to be not the earthquakes in the Kyoto basin but inland earthquakes occurred in the surrounding area. The earthquake damage in Kyoto during the historical period is strongly controlled by ground conditions and earthquakes resistance of buildings rather than distance from the estimated source fault. To better estimate seismic intensity based on building damage, it is necessary to consider the state of buildings (e.g., elapsed years since established, histories of repairs and/or reinforcements, building structures) as well as the strength of ground shakings. By considering the strength of buildings at the time of an earthquake occurrence, the seismic intensity distribution due to historical large earthquakes can be estimated with higher reliability than before. The estimated seismic intensity distribution map for such historical earthquakes can be utilized for developing the strong ground motion prediction in the Kyoto basin.

USGS GNSS Applications to Earthquake Disaster Response and Hazard Mitigation

NASA Astrophysics Data System (ADS)

Hudnut, K. W.; Murray, J. R.; Minson, S. E.

2015-12-01

Rapid characterization of earthquake rupture is important during a disaster because it establishes which fault ruptured and the extent and amount of fault slip. These key parameters, in turn, can augment in situ seismic sensors for identifying disruption to lifelines as well as localized damage along the fault break. Differential GNSS station positioning, along with imagery differencing, are important methods for augmenting seismic sensors. During response to recent earthquakes (1989 Loma Prieta, 1992 Landers, 1994 Northridge, 1999 Hector Mine, 2010 El Mayor - Cucapah, 2012 Brawley Swarm and 2014 South Napa earthquakes), GNSS co-seismic and post-seismic observations proved to be essential for rapid earthquake source characterization. Often, we find that GNSS results indicate key aspects of the earthquake source that would not have been known in the absence of GNSS data. Seismic, geologic, and imagery data alone, without GNSS, would miss important details of the earthquake source. That is, GNSS results provide important additional insight into the earthquake source properties, which in turn help understand the relationship between shaking and damage patterns. GNSS also adds to understanding of the distribution of slip along strike and with depth on a fault, which can help determine possible lifeline damage due to fault offset, as well as the vertical deformation and tilt that are vitally important for gravitationally driven water systems. The GNSS processing work flow that took more than one week 25 years ago now takes less than one second. Formerly, portable receivers needed to be set up at a site, operated for many hours, then data retrieved, processed and modeled by a series of manual steps. The establishment of continuously telemetered, continuously operating high-rate GNSS stations and the robust automation of all aspects of data retrieval and processing, has led to sub-second overall system latency. Within the past few years, the final challenges of standardization and adaptation to the existing framework of the ShakeAlert earthquake early warning system have been met, such that real-time GNSS processing and input to ShakeAlert is now routine and in use. Ongoing adaptation and testing of algorithms remain the last step towards fully operational incorporation of GNSS into ShakeAlert by USGS and its partners.

The CATDAT damaging earthquakes database

NASA Astrophysics Data System (ADS)

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

2011-08-01

The global CATDAT damaging earthquakes and secondary effects (tsunami, fire, landslides, liquefaction and fault rupture) database was developed to validate, remove discrepancies, and expand greatly upon existing global databases; and to better understand the trends in vulnerability, exposure, and possible future impacts of such historic earthquakes. Lack of consistency and errors in other earthquake loss databases frequently cited and used in analyses was a major shortcoming in the view of the authors which needed to be improved upon. Over 17 000 sources of information have been utilised, primarily in the last few years, to present data from over 12 200 damaging earthquakes historically, with over 7000 earthquakes since 1900 examined and validated before insertion into the database. Each validated earthquake includes seismological information, building damage, ranges of social losses to account for varying sources (deaths, injuries, homeless, and affected), and economic losses (direct, indirect, aid, and insured). Globally, a slightly increasing trend in economic damage due to earthquakes is not consistent with the greatly increasing exposure. The 1923 Great Kanto (214 billion USD damage; 2011 HNDECI-adjusted dollars) compared to the 2011 Tohoku (>300 billion USD at time of writing), 2008 Sichuan and 1995 Kobe earthquakes show the increasing concern for economic loss in urban areas as the trend should be expected to increase. Many economic and social loss values not reported in existing databases have been collected. Historical GDP (Gross Domestic Product), exchange rate, wage information, population, HDI (Human Development Index), and insurance information have been collected globally to form comparisons. This catalogue is the largest known cross-checked global historic damaging earthquake database and should have far-reaching consequences for earthquake loss estimation, socio-economic analysis, and the global reinsurance field.

Towards Coupling of Macroseismic Intensity with Structural Damage Indicators

NASA Astrophysics Data System (ADS)

Kouteva, Mihaela; Boshnakov, Krasimir

2016-04-01

Knowledge on basic data of ground motion acceleration time histories during earthquakes is essential to understanding the earthquake resistant behaviour of structures. Peak and integral ground motion parameters such as peak ground motion values (acceleration, velocity and displacement), measures of the frequency content of ground motion, duration of strong shaking and various intensity measures play important roles in seismic evaluation of existing facilities and design of new systems. Macroseismic intensity is an earthquake measure related to seismic hazard and seismic risk description. Having detailed ideas on the correlations between the earthquake damage potential and macroseismic intensity is an important issue in engineering seismology and earthquake engineering. Reliable earthquake hazard estimation is the major prerequisite to successful disaster risk management. The usage of advanced earthquake engineering approaches for structural response modelling is essential for reliable evaluation of the accumulated damages in the existing buildings and structures due to the history of seismic actions, occurred during their lifetime. Full nonlinear analysis taking into account single event or series of earthquakes and the large set of elaborated damage indices are suitable contemporary tools to cope with this responsible task. This paper presents some results on the correlation between observational damage states, ground motion parameters and selected analytical damage indices. Damage indices are computed on the base of nonlinear time history analysis of test reinforced structure, characterising the building stock of the Mediterranean region designed according the earthquake resistant requirements in mid XX-th century.

Earthquake response analysis of 11-story RC building that suffered damage in 2011 East Japan Earthquake

NASA Astrophysics Data System (ADS)

Shibata, Akenori; Masuno, Hidemasa

2017-10-01

An eleven-story RC apartment building suffered medium damage in the 2011 East Japan earthquake and was retrofitted for re-use. Strong motion records were obtained near the building. This paper discusses the inelastic earthquake response analysis of the building using the equivalent single-degree-of-freedom (1-DOF) system to account for the features of damage. The method of converting the building frame into 1-DOF system with tri-linear reducing-stiffness restoring force characteristics was given. The inelastic response analysis of the building against the earthquake using the inelastic 1-DOF equivalent system could interpret well the level of actual damage.

Using the USGS Seismic Risk Web Application to estimate aftershock damage

USGS Publications Warehouse

McGowan, Sean M.; Luco, Nicolas

2014-01-01

The U.S. Geological Survey (USGS) Engineering Risk Assessment Project has developed the Seismic Risk Web Application to combine earthquake hazard and structural fragility information in order to calculate the risk of earthquake damage to structures. Enabling users to incorporate their own hazard and fragility information into the calculations will make it possible to quantify (in near real-time) the risk of additional damage to structures caused by aftershocks following significant earthquakes. Results can quickly be shared with stakeholders to illustrate the impact of elevated ground motion hazard and earthquake-compromised structural integrity on the risk of damage during a short-term, post-earthquake time horizon.

2016 update on induced earthquakes in the United States

USGS Publications Warehouse

Petersen, Mark D.

2016-01-01

During the past decade people living in numerous locations across the central U.S. experienced many more small to moderate sized earthquakes than ever before. This earthquake activity began increasing about 2009 and peaked during 2015 and into early 2016. For example, prior to 2009 Oklahoma typically experienced 1 or 2 small earthquakes per year with magnitude greater than 3.0 but by 2015 this number rose to over 900 earthquakes per year of that size and over 30 earthquakes greater than 4.0. These earthquakes can cause damage. In 2011 a magnitude 5.6 earthquake struck near the town of Prague, Oklahoma on a preexisting fault and caused severe damage to several houses and school buildings. During the past 6 years more than 1500 reports of damaging shaking levels were reported in areas of induced seismicity. This rapid increase and the potential for damaging ground shaking from induced earthquakes caused alarm to about 8 million people living nearby and officials responsible for public safety. They wanted to understand why earthquakes were increasing and the potential threats to society and buildings located nearby.

Preliminary Results of Earthquake-Induced Building Damage Detection with Object-Based Image Classification

NASA Astrophysics Data System (ADS)

Sabuncu, A.; Uca Avci, Z. D.; Sunar, F.

2016-06-01

Earthquakes are the most destructive natural disasters, which result in massive loss of life, infrastructure damages and financial losses. Earthquake-induced building damage detection is a very important step after earthquakes since earthquake-induced building damage is one of the most critical threats to cities and countries in terms of the area of damage, rate of collapsed buildings, the damage grade near the epicenters and also building damage types for all constructions. Van-Ercis (Turkey) earthquake (Mw= 7.1) was occurred on October 23th, 2011; at 10:41 UTC (13:41 local time) centered at 38.75 N 43.36 E that places the epicenter about 30 kilometers northern part of the city of Van. It is recorded that, 604 people died and approximately 4000 buildings collapsed or seriously damaged by the earthquake. In this study, high-resolution satellite images of Van-Ercis, acquired by Quickbird-2 (Digital Globe Inc.) after the earthquake, were used to detect the debris areas using an object-based image classification. Two different land surfaces, having homogeneous and heterogeneous land covers, were selected as case study areas. As a first step of the object-based image processing, segmentation was applied with a convenient scale parameter and homogeneity criterion parameters. As a next step, condition based classification was used. In the final step of this preliminary study, outputs were compared with streetview/ortophotos for the verification and evaluation of the classification accuracy.

Damage and intensity survey

USGS Publications Warehouse

Reagor, G.; Brewer, L.R.

1992-01-01

A field team (the tuhors) from the National Earthquake Information Center (USGS) conducted a damage survey of the epicentral area in the week following the earthquakes. Detailed information about damage and where and how strongly the earthquakes were felt was obtained through interviews with local residents and personal observations. 

Chimney damage in the greater Seattle area from the Nisqually earthquake of 28 February 2001

USGS Publications Warehouse

Booth, D.B.; Wells, R.E.; Givler, R.W.

2004-01-01

Unreinforced brick chimneys in the greater Seattle area were damaged repeatedly in the Benioff zone earthquakes of 1949, 1965, and 2001. A survey of visible chimney damage after the 28 February 2001 Nisqually earthquake evaluated approximately 60,000 chimneys through block-by-block coverage of about 50 km2, identifying a total of 1556 damaged chimneys. Chimney damage was strongly clustered in certain areas, in particular in the neighborhood of West Seattle where prior damage was also noted and evaluated after the 1965 earthquake. Our results showed that damage produced by the 2001 earthquake did not obviously correspond to distance from the earthquake epicenter, soft soils, topography, or slope orientation. Chimney damage correlates well to instrumented strong-motion measurements and compiled resident-reported ground-shaking intensities, but it offers much finer spatial resolution than these other data sources. In general, most areas of greatest chimney damage coincide with best estimated locations of strands of the Seattle fault zone. The edge of that zone also coincides with areas where chimney damage dropped abruptly over only one or two blocks' distance. The association between shaking intensity and fault-zone structure suggests that abrupt changes in the depth to bedrock, edge effects at the margin of the Seattle basin, or localized trapping of seismic waves in the Seattle fault zone may be significant contributory factors in the distribution of chimney damage.

Earthquakes, September-October 1980

USGS Publications Warehouse

Person, W.J.

1981-01-01

There were two major (magnitudes 7.0-7.9) earthquakes during this reporting period; a magnitude (M) 7.3 in Algeria where many people were killed or injured and extensive damage occurred, and an M=7.2 in the Loyalty Islands region of the South Pacific. Japan was struck by a damaging earthquake on September 24, killing two people and causing injuries. There were no damaging earthquakes in the United States. 

Statistical analysis of low-rise building damage caused by the San Fernando earthquake

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

Scholl, R.E.

1974-02-01

An empirical investigation of damage to low-rise buildings in two selected control areas within Glendale, California, caused by the ground motion precipitated by the San Fernando earthquake of February 9, 1971 is summarized. The procedures for obtaining the appropriate data and the methodology used in deriving ground motion-damage relationships are described. Motion-damage relationships are derived for overall damage and for the most frequently damaged building components. Overall motion-damage relationships are expressed in terms of damage incidence (damage ratio) and damage cost (damage cost factor). The motion-damage relationships derived from the earthquake data are compared with similar data obtained for lou-risemore » buildings subjected to ground motion generated by an underground nuclear explosion. Overall comparison results show that for the same spectral acceleration, the earthquake caused slightly more damage. Differences in ground-motion characteristics for the two types of disturbances provide the most probable explanation for this discrepancy. (auth)« less

Earthquakes in Ohio and Vicinity 1776-2007

USGS Publications Warehouse

Dart, Richard L.; Hansen, Michael C.

2008-01-01

This map summarizes two and a third centuries of earthquake activity. The seismic history consists of letters, journals, diaries, and newspaper and scholarly articles that supplement seismograph recordings (seismograms) dating from the early twentieth century to the present. All of the pre-instrumental (historical) earthquakes were large enough to be felt by people or to cause shaking damage to buildings and their contents. Later, widespread use of seismographs meant that tremors too small or distant to be felt could be detected and accurately located. Earthquakes are a legitimate concern in Ohio and parts of adjacent States. Ohio has experienced more than 160 felt earthquakes since 1776. Most of these events caused no damage or injuries. However, 15 Ohio earthquakes resulted in property damage and some minor injuries. The largest historic earthquake in the state occurred in 1937. This event had an estimated magnitude of 5.4 and caused considerable damage in the town of Anna and in several other western Ohio communities. The large map shows all historical and instrumentally located earthquakes from 1776 through 2007.

Journal of the Chinese Institute of Engineers. Special Issue: Commemoration of Chi-Chi Earthquake (II)

NASA Astrophysics Data System (ADS)

2002-09-01

Contents include the following: Deep Electromagnetic Images of Seismogenic Zone of the Chi-Chi (Taiwan) Earthquake; New Techniques for Stress-Forecasting Earthquakes; Aspects of Characteristics of Near-Fault Ground Motions of the 1999 Chi-Chi (Taiwan) Earthquake; Liquefaction Damage and Related Remediation in Wufeng after the Chi-Chi Earthquake; Fines Content Effects on Liquefaction Potential Evaluation for Sites Liquefied during Chi-Chi Earthquake 1999; Damage Investigation and Liquefaction Potential Analysis of Gravelly Soil; Dynamic Characteristics of Soils in Yuan-Lin Liquefaction Area; A Preliminary Study of Earthquake Building Damage and Life Loss Due to the Chi-Chi Earthquake; Statistical Analyses of Relation between Mortality and Building Type in the 1999 Chi-Chi Earthquake; Development of an After Earthquake Disaster Shelter Evaluation Model; Posttraumatic Stress Reactions in Children and Adolescents One Year after the 1999 Taiwan Chi-Chi Earthquake; Changes or Not is the Question: the Meaning of Posttraumatic Stress Reactions One Year after the Taiwan Chi-Chi Earthquake.

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

NASA Astrophysics Data System (ADS)

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

2011-12-01

Under ARIA (Advanced Rapid Imaging and Analysis) project at JPL and Caltech, we developed a prototype algorithm to detect surface property change caused by natural or man-made damage using InSAR coherence change. The algorithm was tested on building demolition and construction sites in downtown Pasadena, California. The developed algorithm performed significantly better, producing 150 % higher signal-to-noise ratio, than a standard coherence change detection method. We applied the algorithm to February 2011 M6.3 Christchurch earthquake in New Zealand, 2011 M9.0 Tohoku-oki earthquake in Japan, and 2011 Kirishima volcano eruption in Kyushu, Japan, using ALOS PALSAR data. In Christchurch area we detected three different types of damage: liquefaction, building collapse, and landslide. The detected liquefaction damage is extensive in the eastern suburbs of Christchurch, showing Bexley as one of the most significantly affected areas as was reported in the media. Some places show sharp boundaries of liquefaction damage, indicating different type of ground materials that might have been formed by the meandering Avon River in the past. Well reported damaged buildings such as Christchurch Cathedral, Canterbury TV building, Pyne Gould building, and Cathedral of the Blessed Sacrament were detected by the algorithm. A landslide in Redcliffs was also clearly detected. These detected damage sites were confirmed with Google earth images provided by GeoEye. Larger-scale damage pattern also agrees well with the ground truth damage assessment map indicated with polygonal zones of 3 different damage levels, compiled by the government of New Zealand. The damage proxy map of Sendai area in Japan shows man-made structure damage due to the tsunami caused by the M9.0 Tohoku-oki earthquake. Long temporal baseline (~2.7 years) and volume scattering caused significant decorrelation in the farmlands and bush forest along the coastline. The 2011 Kirishima volcano eruption caused a lot of ash fall deposit in the southeast from the volcano. The detected ash fall damage area exactly matches the in-situ measurements implemented through fieldwork by Geological Survey of Japan. With 99-percentile threshold for damage detection, the periphery of the detected damage area aligns with a contour line of 100 kg/m2 ash deposit, equivalent to 10 cm of depth assuming a density of 1000 kg/m3 for the ash layer. With growing number of InSAR missions, rapidly produced accurate damage assessment maps will help save people, assisting effective prioritization of rescue operations at early stage of response, and significantly improve timely situational awareness for emergency management and national / international assessment and response for recovery planning. Results of this study will also inform the design of future InSAR missions including the proposed DESDynI.

What kind of disturbances did March 11, 2011 Tohoku Earthquake and Tsunamis leave continental margin ecosystems? : Lessons from five years monitoring research

NASA Astrophysics Data System (ADS)

Kitazato, Hiroshi; Kijima, Akihiro; Kogure, Kazuhiro; Hara, Motoyuki; Nagata, Toshi; Fujikura, Kasunori; Sonoda, Akira

2016-04-01

On March 11, 2011, huge earthquake with M9.0 took place at Japan Trench area off Northeast Japan. Vigorous disturbances of marine environments and ecosystems have taken place at coastal areas where huge tsunamis swept sediments and organisms away from the coastal areas to deeper oceans. Distributional pattern of sediments and organisms in coves and bays have strongly changed after tsunamis. Marine ecosystems at Northeast Japan have totally disturbed and damaged. Scientists from Tohoku University, the University of Tokyo and JAMSTEC have started to monitor how much marine ecosystem disturbed and how it may recover. A research team, named Tohoku Ecosystem-Associated Marine Sciences, continually makes research on marine ecosystems as ten years monitoring project funded by MEXT, Japan since 2011. On 2016, it takes five years from the Earthquake and Tsunami occurred. What happens marine ecosystems at Tohoku area during these years. Water column ecosystems are rather easy to recover from disturbances. Seaweed communities have strongly damaged, but, they gradually recover. Sediment communities have not recovered yet as sediment distribution is different from before earthquake and tsunamis. Most difficulties are scars in human minds. We, scientists, try to share scientific activities and results with local peoples including fishermen and local governments for better understanding of both oceanic conditions and fishery resources. Disaster risk reduction should accelerate with resilience of community structure. But, mental resilience is the most effective way to recover human activities at the damaged areas.

Optical methods in fault dynamics

NASA Astrophysics Data System (ADS)

Uenishi, K.; Rossmanith, H. P.

2003-10-01

The Rayleigh pulse interaction with a pre-stressed, partially contacting interface between similar and dissimilar materials is investigated experimentally as well as numerically. This study is intended to obtain an improved understanding of the interface (fault) dynamics during the earthquake rupture process. Using dynamic photoelasticity in conjunction with high-speed cinematography, snapshots of time-dependent isochromatic fringe patterns associated with Rayleigh pulse-interface interaction are experimentally recorded. It is shown that interface slip (instability) can be triggered dynamically by a pulse which propagates along the interface at the Rayleigh wave speed. For the numerical investigation, the finite difference wave simulator SWIFD is used for solving the problem under different combinations of contacting materials. The effect of acoustic impedance ratio of the two contacting materials on the wave patterns is discussed. The results indicate that upon interface rupture, Mach (head) waves, which carry a relatively large amount of energy in a concentrated form, can be generated and propagated from the interface contact region (asperity) into the acoustically softer material. Such Mach waves can cause severe damage onto a particular region inside an adjacent acoustically softer area. This type of damage concentration might be a possible reason for the generation of the "damage belt" in Kobe, Japan, on the occasion of the 1995 Hyogo-ken Nanbu (Kobe) Earthquake.

Site effects in Avcilar, West of Istanbul, Turkey, from strong- and weak-motion data

USGS Publications Warehouse

Ozel, O.; Cranswick, E.; Meremonte, M.; Erdik, M.; Safak, E.

2002-01-01

Approximately 1000 people were killed in the collapse of buildings in Istanbul, Turkey, during the 17 August 1999 I??zmit earthquake, whose epicenter was roughly 90 km east of the city. Most of the fatalities and damage occurred in the suburb of Avcilar that is 20 km further west of the epicenter than the city proper. To investigate this pattern of damage, the U.S. Geological Survey, in cooperation with the Kandilli Observatory and Earthquake Research Institute (KOERI), deployed portable digital seismographs at seven free-field sites in western Istanbul, to record aftershocks during the period from 24 August to 2 September. The primary objective of this deployment was to study the site effects by comparing the aftershock ground motions recorded at sites inside and outside the damaged area, and to correlate site effects with the distribution of the damaged buildings. In addition to using weak-motion data, mainshock and aftershock acceleration records from the KOERI permanent strong-motion array were also used in estimating the site effects. Site effects were estimated using S waves from both types of records. For the weak-motion data set, 22 events were selected according to the criteria of signal-to-noise ratio (S/N ratio) and the number of stations recording the same event. The magnitudes of these events ranged from 3.0 to 5.2. The acceleration data set consisted of 12 events with magnitudes ranging from 4.3 to 5.8 and included two mainshock events. Results show that the amplifying frequency band is, in general, less than 4 Hz, and the physical properties of the geologic materials are capable of amplifying the motions by a factor of 5-10. In this frequency band, there is a good agreement among the spectral ratios obtained from the two mainshocks and their aftershocks. The damage pattern for the 17 August I??zmit earthquake is determined by several factors. However, our study suggests that the site effects in Avcilar played an important role in contributing to the damage.

Liquefaction and soil failure during 1994 northridge earthquake

USGS Publications Warehouse

Holzer, T.L.

1999-01-01

The 1994 Northridge, Calif., earthquake caused widespread permanent ground deformation on the gently sloping alluvial fan surface of the San Fernando Valley. The ground cracks and distributed deformation damaged both pipelines and surface structures. To evaluate the mechanism of soil failure, detailed subsurface investigations were conducted at four sites. Three sites are underlain by saturated sandy silts with low standard penetration test and cone penetration test values. These soils are similar to those that liquefied during the 1971 San Fernando earthquake, and are shown by widely used empirical relationships to be susceptible to liquefaction. The remaining site is underlain by saturated clay whose undrained shear strength is approximately half the value of the earthquake-induced shear stress at this location. This study demonstrates that the heterogeneous nature of alluvial fan sediments in combination with variations in the ground-water table can be responsible for complex patterns of permanent ground deformation. It may also help to explain some of the spatial variability of strong ground motion observed during the 1994 earthquake. ?? ASCE,.

Effects of the earthquake of March 27, 1964, on the Eklutna Hydroelectric Project, Anchorage, Alaska, with a section on television examination of earthquake damage to underground communication and electrical systems in Anchorage: Chapter A in The Alaska earthquake, March 27, 1964: effects on transportation, communications, and utilities

USGS Publications Warehouse

Logan, Malcolm H.; Burton, Lynn R.

1967-01-01

The March 27, 1964, Alaska earthquake and its associated aftershocks caused damage requiring several million dollars worth of repair to the Eklwtna Hydroelectric Project, 34 miles northeast of Anchorage. Electric service from the Eklutna powerplant was interrupted during the early phase of the March 27 earthquake, built was restored (intermittently) until May 9,1964, when the plant was closed for inspection and repair. Water for Eklutna project is transported from Eklutna Lake to the powerplant at tidewater on Knik Arm of Cook Inlet by an underwater intake connected to a 4.46-mile tunnel penstock. The primary damage caused by the earthquake was 1at the intake structure in Eklutna Lake. No damage to the power tunnel was observed. The piles-supported powerplant and appurtenant structures, Anchorage and Palmer substations, and the transmission lines suffered minor dammage. Most damage occurred to facilities constructed on un-consolidated sediments and overburden which densified and subsided during the earthquake. Structures built on bedrock experienced little or no damage. Underground communication and electrical systems in Anchorage were examined with a small-diameter television camera to locate damaged areas requiring repair. Most of the damage was concentrated at or near valley slopes. Those parts of the systems within the major slide areas of the city were destroyed.

An overview of the geotechnical damage brought by the 2016 Kumamoto Earthquake, Japan

USGS Publications Warehouse

Hemanta Hazarika,; Takaji Kokusho,; Kayen, Robert E.; Dashti, Shideh; Yutaka Tanoue,; Shuuichi Kuroda and Kentaro Kuribayashi,; Daisuke Matsumoto,; Furuichi, Hideo

2016-01-01

The 2016 Kumamoto earthquake with a moment magnitude of 7.0 (Japanese intensity = 7) that struck on April 16 brought devastation in many areas of Kumamoto Prefecture and partly in Oita Prefecture in Kyushu Region, Japan. The earthquake succeeds a foreshock of magnitude 6.5 (Japanese intensity = 7) on April 14. The authors conducted two surveys on the devastated areas: one during April 16-17, and the other during May 11-14. This report summarizes the damage brought to geotechnical structures by the two consecutive earthquakes within a span of twenty-eight hours. This report highlights some of the observed damage and identifies reasons for such damage. The geotechnical challenges towards mitigation of losses from such earthquakes are also suggested.

Feasibility Study of Earthquake Early Warning in Hawai`i For the Mauna Kea Thirty Meter Telescope

NASA Astrophysics Data System (ADS)

Okubo, P.; Hotovec-Ellis, A. J.; Thelen, W. A.; Bodin, P.; Vidale, J. E.

2014-12-01

Earthquakes, including large damaging events, are as central to the geologic evolution of the Island of Hawai`i as its more famous volcanic eruptions and lava flows. Increasing and expanding development of facilities and infrastructure on the island continues to increase exposure and risk associated with strong ground shaking resulting from future large local earthquakes. Damaging earthquakes over the last fifty years have shaken the most heavily developed areas and critical infrastructure of the island to levels corresponding to at least Modified Mercalli Intensity VII. Hawai`i's most recent damaging earthquakes, the M6.7 Kiholo Bay and M6.0 Mahukona earthquakes, struck within seven minutes of one another off of the northwest coast of the island in October 2006. These earthquakes resulted in damage at all thirteen of the telescopes near the summit of Mauna Kea that led to gaps in telescope operations ranging from days up to four months. With the experiences of 2006 and Hawai`i's history of damaging earthquakes, we have begun a study to explore the feasibility of implementing earthquake early warning systems to provide advanced warnings to the Thirty Meter Telescope of imminent strong ground shaking from future local earthquakes. One of the major challenges for earthquake early warning in Hawai`i is the variety of earthquake sources, from shallow crustal faults to deeper mantle sources, including the basal decollement separating the volcanic pile from the ancient oceanic crust. Infrastructure on the Island of Hawai`i may only be tens of kilometers from these sources, allowing warning times of only 20 s or less. We assess the capability of the current seismic network to produce alerts for major historic earthquakes, and we will provide recommendations for upgrades to improve performance.

Lessons learned from the 2016 Kumamoto earthquake: Building damages and behavior of seismically isolated buildings

NASA Astrophysics Data System (ADS)

Morita, Keiko; Takayama, Mineo

2017-10-01

Powerful earthquakes stuck Kumamoto and Oita Prefectures in Kyushu, Japan. It began with the Magnitude 6.5 foreshock at 21:26 JST 14 April, followed by the Magnitude 7.3 mainshock at 1:25 JST 16 April, 2016. The sequence earthquakes also involved more than 1700 perceptible earthquakes as of 13 June. The entire sequence was named the 2016 Kumamoto earthquake by the Japan Meteorological Agency. Thousands of buildings and many roads were damaged, and landslides occurred. The Japanese building standard law is revised in 1981. Structural damages were concentrated on buildings constructed prior to 1981. The area of Mashiki and Southern Aso were most badly affected, especially wooden houses extremely damaged. In Japan, Prof. Hideyuki Tada (title at the time) undertook research on laminated rubber bearings in 1978, and put it into practical use in 1981. The single family house at Yachiyodai, Chiba Prefecture is completed in 1983, it's the first seismically isolated building which is installed laminated rubber bearings in Japan. Afterward, this system is gradually adopted to mainly office buildings, like a research laboratory, a hospital, a computer center and other offices. In the 1994 Northridge earthquake, the 1995 Kobe earthquake and 2011 Tohoku earthquake, seismically isolated buildings improve these good performances, and recently number of the buildings have increased, mainly high risk area of earthquakes. Many people believed that Kumamoto was a low risk area. But there were 24 seismically isolated buildings in Kumamoto Prefecture at the time. The seismically isolated buildings indicated excellent performances during the earthquakes. They protected people, buildings and other important facilities from damages caused by the earthquake. The purpose of this paper is to discuss lessons learned from the 2016 Kumamoto earthquake and behavior of seismically isolated buildings in the earthquake.

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.  

Damaged Speleothems of the Ms 8.0 Wenchuan Earthquake, China, and the Implications for Seismology

NASA Astrophysics Data System (ADS)

Xueqin, Zhao; Fudong, Wang

2017-04-01

Broken or deformed speleothems can be used for paleoseismic research since they can be dated with radiometric techniques. But it rarely happens that speleologists are in caves just at the time of strong earthquake shocks, and there are only a few published cases of observations from caves visited immediately after an earthquake. So that it is really plausible that earthquakes break speleothem. Therefore, it needs more evidence of recent strong seismic to prove the way of speleoseismology. In order to provide more on-site data for speleoseismology, four underground cavities in the Longmenshan Fault Zone where a devastating Ms 8.0 earthquake has occurred at 2:28 pm, May 12, 2008, have been selected for speleoseismic analysis. We document damaged carbonate cave deposits by Wenchuan earthquake, including collapsed and broken stalactites, in-situ severed stalagmites and stalactites, collapsed bedrock ceilings, and strictures; and discuss the implications of damaged speleothems as possible earthquake recorder. The results show that massive damaged speleothem, as an effective method for paleoseismic, can compatible with strong earthquake.

Rapid and Near Real-Time Assessments of Population Displacement Using Mobile Phone Data Following Disasters: The 2015 Nepal Earthquake.

PubMed

Wilson, Robin; Zu Erbach-Schoenberg, Elisabeth; Albert, Maximilian; Power, Daniel; Tudge, Simon; Gonzalez, Miguel; Guthrie, Sam; Chamberlain, Heather; Brooks, Christopher; Hughes, Christopher; Pitonakova, Lenka; Buckee, Caroline; Lu, Xin; Wetter, Erik; Tatem, Andrew; Bengtsson, Linus

2016-02-24

Sudden impact disasters often result in the displacement of large numbers of people. These movements can occur prior to events, due to early warning messages, or take place post-event due to damages to shelters and livelihoods as well as a result of long-term reconstruction efforts. Displaced populations are especially vulnerable and often in need of support. However, timely and accurate data on the numbers and destinations of displaced populations are extremely challenging to collect across temporal and spatial scales, especially in the aftermath of disasters. Mobile phone call detail records were shown to be a valid data source for estimates of population movements after the 2010 Haiti earthquake, but their potential to provide near real-time ongoing measurements of population displacements immediately after a natural disaster has not been demonstrated. A computational architecture and analytical capacity were rapidly deployed within nine days of the Nepal earthquake of 25th April 2015, to provide spatiotemporally detailed estimates of population displacements from call detail records based on movements of 12 million de-identified mobile phones users. Analysis shows the evolution of population mobility patterns after the earthquake and the patterns of return to affected areas, at a high level of detail. Particularly notable is the movement of an estimated 390,000 people above normal from the Kathmandu valley after the earthquake, with most people moving to surrounding areas and the highly-populated areas in the central southern area of Nepal. This analysis provides an unprecedented level of information about human movement after a natural disaster, provided within a very short timeframe after the earthquake occurred. The patterns revealed using this method are almost impossible to find through other methods, and are of great interest to humanitarian agencies.

Earthquakes, November-December 1977

USGS Publications Warehouse

Person, W.J.

1978-01-01

In the United States, the largest earthquake during this reporting period was a magntidue 6.6 in the Andreanof Islands, which are part of the Aleutian Islands chain, on November 4 that caused some minor damage. Northern California was struck by a magnitude 4.8 earthquake on November 22 causing moderate damage in the Willits area. This was the most damaging quake in the United States during the year. Two major earthquakes of magntidues 7.0 or above to 14 for the year. 

Business losses, transportation damage and the Northridge Earthquake

DOT National Transportation Integrated Search

1998-05-01

The 1994 Northridge earthquake damaged four major freeways in the Los Angeles area. Southern California firms were surveyed to assess the role that these transportation disruptions played in business losses. Of the firms that reported any earthquake ...

Earthquakes, July-August, 1979

USGS Publications Warehouse

Person, W.J.

1980-01-01

In the United States, on August 6, central California experienced a moderately strong earthquake, which injured several people and caused some damage. A number of earthquakes occurred in other parts of the United States but caused very little damage. 

The ShakeOut Scenario

USGS Publications Warehouse

Jones, Lucile M.; Bernknopf, Richard; Cox, Dale; Goltz, James; Hudnut, Kenneth; Mileti, Dennis; Perry, Suzanne; Ponti, Daniel; Porter, Keith; Reichle, Michael; Seligson, Hope; Shoaf, Kimberley; Treiman, Jerry; Wein, Anne

2008-01-01

This is the initial publication of the results of a cooperative project to examine the implications of a major earthquake in southern California. The study comprised eight counties: Imperial, Kern, Los Angeles, Orange, Riverside, San Bernardino, San Diego, and Ventura. Its results will be used as the basis of an emergency response and preparedness exercise, the Great Southern California ShakeOut, and for this purpose we defined our earthquake as occurring at 10:00 a.m. on November 13, 2008. As members of the southern California community use the ShakeOut Scenario to plan and execute the exercise, we anticipate discussion and feedback. This community input will be used to refine our assessment and will lead to a formal publication in early 2009. Our goal in the ShakeOut Scenario is to identify the physical, social and economic consequences of a major earthquake in southern California and in so doing, enable the users of our results to identify what they can change now?before the earthquake?to avoid catastrophic impact after the inevitable earthquake occurs. To do so, we had to determine the physical damages (casualties and losses) caused by the earthquake and the impact of those damages on the region?s social and economic systems. To do this, we needed to know about the earthquake ground shaking and fault rupture. So we first constructed an earthquake, taking all available earthquake research information, from trenching and exposed evidence of prehistoric earthquakes, to analysis of instrumental recordings of large earthquakes and the latest theory in earthquake source physics. We modeled a magnitude (M) 7.8 earthquake on the southern San Andreas Fault, a plausible event on the fault most likely to produce a major earthquake. This information was then fed forward into the rest of the ShakeOut Scenario. The damage impacts of the scenario earthquake were estimated using both HAZUS-MH and expert opinion through 13 special studies and 6 expert panels, and fall into four categories: building damages, non-structural damages, damage to lifelines and infrastructure, and fire losses. The magnitude 7.8 ShakeOut earthquake is modeled to cause about 1800 deaths and $213 billion of economic losses. These numbers are as low as they are because of aggressive retrofitting programs that have increased the seismic resistance of buildings, highways and lifelines, and economic resiliency. These numbers are as large as they are because much more retrofitting could still be done. The earthquake modeled here may never happen. Big earthquakes on the San Andreas Fault are inevitable, and by geologic standards extremely common, but probably will not be exactly like this one. The next very damaging earthquake could easily be on another fault. However, lessons learned from this particular event apply to many other events and could provide benefits in many possible future events.

Earthquake outlook for the San Francisco Bay region 2014–2043

USGS Publications Warehouse

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

2016-06-13

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

Site response, shallow shear-wave velocity, and damage in Los Gatos, California, from the 1989 Loma Prieta earthquake

USGS Publications Warehouse

Hartzell, S.; Carver, D.; Williams, R.A.

2001-01-01

Aftershock records of the 1989 Loma Prieta earthquake are used to calculate site response in the frequency band of 0.5-10 Hz at 24 locations in Los Gatos, California, on the edge of the Santa Clara Valley. Two different methods are used: spectral ratios relative to a reference site on rock and a source/site spectral inversion method. These two methods complement each other and give consistent results. Site amplification factors are compared with surficial geology, thickness of alluvium, shallow shear-wave velocity measurements, and ground deformation and structural damage resulting from the Loma Prieta earthquake. Higher values of site amplification are seen on Quaternary alluvium compared with older Miocene and Cretaceous units of Monterey and Franciscan Formation. However, other more detailed correlations with surficial geology are not evident. A complex pattern of alluvial sediment thickness, caused by crosscutting thrust faults, is interpreted as contributing to the variability in site response and the presence of spectral resonance peaks between 2 and 7 Hz at some sites. Within the range of our field measurements, there is a correlation between lower average shear-wave velocity of the top 30 m and 50% higher values of site amplification. An area of residential homes thrown from their foundations correlates with high site response. This damage may also have been aggravated by local ground deformation. Severe damage to commercial buildings in the business district, however, is attributed to poor masonry construction.

Earthquake damage to transportation systems

USGS Publications Warehouse

McCullough, Heather

1994-01-01

Earthquakes represent one of the most destructive natural hazards known to man. A large magnitude earthquake near a populated area can affect residents over thousands of square kilometers and cause billions of dollars in property damage. Such an event can kill or injure thousands of residents and disrupt the socioeconomic environment for months, sometimes years. A serious result of a large-magnitude earthquake is the disruption of transportation systems, which limits post-disaster emergency response. Movement of emergency vehicles, such as police cars, fire trucks and ambulances, is often severely restricted. Damage to transportation systems is categorized below by cause including: ground failure, faulting, vibration damage, and tsunamis.

An Account of Preliminary Landslide Damage and Losses Resulting from the February 28, 2001, Nisqually, Washington, Earthquake

USGS Publications Warehouse

Highland, Lynn M.

2003-01-01

The February 28, 2001, Nisqually, Washington, earthquake (Mw = 6.8) damaged an area of the northwestern United States that previously experienced two major historical earthquakes, in 1949 and in 1965. Preliminary estimates of direct monetary losses from damage due to earthquake-induced landslides is approximately $34.3 million. However, this figure does not include costs from damages to the elevated portion of the Alaskan Way Viaduct, a major highway through downtown Seattle, Washington that will be repaired or rebuilt, depending on the future decision of local and state authorities. There is much debate as to the cause of the damage to this viaduct with evaluations of cause ranging from earthquake shaking and liquefaction to lateral spreading to a combination of these effects. If the viaduct is included in the costs, the losses increase to $500+ million (if it is repaired) or to more than $1+ billion (if it is replaced). Preliminary estimate of losses due to all causes of earthquake damage is approximately $2 billion, which includes temporary repairs to the Alaskan Way Viaduct. These preliminary dollar figures will no doubt increase when plans and decisions regarding the Viaduct are completed.

ShakeCast: Automating and improving the use of shakemap for post-earthquake deeision-making and response

USGS Publications Warehouse

Wald, D.; Lin, K.-W.; Porter, K.; Turner, Loren

2008-01-01

When a potentially damaging earthquake occurs, utility and other lifeline managers, emergency responders, and other critical users have an urgent need for information about the impact on their particular facilities so they can make appropriate decisions and take quick actions to ensure safety and restore system functionality. ShakeMap, a tool used to portray the extent of potentially damaging shaking following an earthquake, on its own can be useful for emergency response, loss estimation, and public information. However, to take full advantage of the potential of ShakeMap, we introduce ShakeCast. ShakeCast facilitates the complicated assessment of potential damage to a user's widely distributed facilities by comparing the complex shaking distribution with the potentially highly variable damageability of their inventory to provide a simple, hierarchical list and maps of structures or facilities most likely impacted. ShakeCast is a freely available, post-earthquake situational awareness application that automatically retrieves earthquake shaking data from ShakeMap, compares intensity measures against users' facilities, sends notifications of potential damage to responsible parties, and generates facility damage maps and other Web-based products for both public and private emergency managers and responders. ?? 2008, Earthquake Engineering Research Institute.

Earthquake-driven fluid flow rates inferred from borehole temperature measurements within the Japan Trench plate boundary fault zone

NASA Astrophysics Data System (ADS)

Fulton, P. M.; Brodsky, E. E.

2016-12-01

Using borehole sub-seafloor temperature measurements, we have recently identified signatures suggestive of earthquake-driven fluid pulses within the Japan Trench plate boundary fault zone during a major aftershock sequence. Here we use numerical models to show that these signatures are consistent with time-varying fluid flow rates out of permeable zones within the formation into the borehole annulus. In addition, we also identify an apparent time-varying sensitivity of whether suspected fluid pulses occur in response to earthquakes of a given magnitude and distance. The results suggest a damage and healing process and therefore provides a mechanism to allow for a disproportionate amount of heat and chemical transport in the short time frame after an earthquake. Our observations come from an observatory installed across the main plate boundary fault as part of IODP's Japan Trench Fast Drilling Project (JFAST) following the March 2011 Mw 9.0 Tohoku-oki earthquake. It operated from July 2012 - April 2013 during which a Mw 7.3 earthquake and numerous aftershocks occurred. High-resolution temperature time series data reveal spatially correlated transients in response to earthquakes with distinct patterns interpreted to reflect advection by transient pulses of fluid flow from permeable zones into the borehole annulus. Typical transients involve perturbations over 12 m with increases of 10 mK that build over 0.1 days at shallower depths and decreases at deeper depths. They are consistently centered around 792.5 m below seafloor (mbsf) where a secondary fault and permeable zone have been independently identified within the damage zone above the main plate boundary fault at 820 mbsf . Model simulations suggest transient flow rates of up to 10-3m/s from the formation that quickly decrease. Comparison of characteristics of earthquakes identified in nearby ocean bottom pressure measurements suggest there is not a clear relationship between fluid pulses and static strain. There does appear to be a time-varying sensitivity likely from dynamic stresses suggestive of a damage process followed by healing over 1 month time. The transient redistribution of fluid pressures and fluid flow within fault zones inferred here is a potential mechanism for earthquake triggering and episodic heat and chemical transport.

Recognition of earthquake-related damage in archaeological sites: Examples from the Dead Sea fault zone

NASA Astrophysics Data System (ADS)

Marco, Shmuel

2008-06-01

Archaeological structures that exhibit seismogenic damage expand our knowledge of temporal and spatial distribution of earthquakes, afford independent examination of historical accounts, provide information on local earthquake intensities and enable the delineation of macroseismic zones. They also illustrate what might happen in future earthquakes. In order to recover this information, we should be able to distinguish earthquake damage from anthropogenic damage and from other natural processes of wear and tear. The present paper reviews several types of damage that can be attributed with high certainty to earthquakes and discusses associated caveats. In the rare cases, where faults intersect with archaeological sites, offset structures enable precise determination of sense and size of slip, and constrain its time. Among the characteristic off-fault damage types, I consider horizontal shifting of large building blocks, downward sliding of one or several blocks from masonry arches, collapse of heavy, stably-built walls, chipping of corners of building blocks, and aligned falling of walls and columns. Other damage features are less conclusive and require additional evidence, e.g., fractures that cut across several structures, leaning walls and columns, warps and bulges in walls. Circumstantial evidence for catastrophic earthquake-related destruction includes contemporaneous damage in many sites in the same area, absence of weapons or other anthropogenic damage, stratigraphic data on collapse of walls and ceilings onto floors and other living horizons and burial of valuable artifacts, as well as associated geological palaeoseismic phenomena such as liquefaction, land- and rock-slides, and fault ruptures. Additional support may be found in reliable historical accounts. Special care must be taken in order to avoid circular reasoning by maintaining the independence of data acquisition methods.

Global observation of Omori-law decay in the rate of triggered earthquakes

NASA Astrophysics Data System (ADS)

Parsons, T.

2001-12-01

Triggered earthquakes can be large, damaging, and lethal as evidenced by the 1999 shocks in Turkey and the 2001 events in El Salvador. In this study, earthquakes with M greater than 7.0 from the Harvard CMT catalog are modeled as dislocations to calculate shear stress changes on subsequent earthquake rupture planes near enough to be affected. About 61% of earthquakes that occurred near the main shocks are associated with calculated shear stress increases, while ~39% are associated with shear stress decreases. If earthquakes associated with calculated shear stress increases are interpreted as triggered, then such events make up at least 8% of the CMT catalog. Globally, triggered earthquakes obey an Omori-law rate decay that lasts between ~7-11 years after the main shock. Earthquakes associated with calculated shear stress increases occur at higher rates than background up to 240 km away from the main-shock centroid. Earthquakes triggered by smaller quakes (foreshocks) also obey Omori's law, which is one of the few time-predictable patterns evident in the global occurrence of earthquakes. These observations indicate that earthquake probability calculations which include interactions from previous shocks should incorporate a transient Omori-law decay with time. In addition, a very simple model using the observed global rate change with time and spatial distribution of triggered earthquakes can be applied to immediately assess the likelihood of triggered earthquakes following large events, and can be in place until more sophisticated analyses are conducted.

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

Update earthquake risk assessment in Cairo, Egypt

NASA Astrophysics Data System (ADS)

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

2017-07-01

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

Development of damage probability matrices based on Greek earthquake damage data

NASA Astrophysics Data System (ADS)

Eleftheriadou, Anastasia K.; Karabinis, Athanasios I.

2011-03-01

A comprehensive study is presented for empirical seismic vulnerability assessment of typical structural types, representative of the building stock of Southern Europe, based on a large set of damage statistics. The observational database was obtained from post-earthquake surveys carried out in the area struck by the September 7, 1999 Athens earthquake. After analysis of the collected observational data, a unified damage database has been created which comprises 180,945 damaged buildings from/after the near-field area of the earthquake. The damaged buildings are classified in specific structural types, according to the materials, seismic codes and construction techniques in Southern Europe. The seismic demand is described in terms of both the regional macroseismic intensity and the ratio α g/ a o, where α g is the maximum peak ground acceleration (PGA) of the earthquake event and a o is the unique value PGA that characterizes each municipality shown on the Greek hazard map. The relative and cumulative frequencies of the different damage states for each structural type and each intensity level are computed in terms of damage ratio. Damage probability matrices (DPMs) and vulnerability curves are obtained for specific structural types. A comparison analysis is fulfilled between the produced and the existing vulnerability models.

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.   

Estimating shaking-induced casualties and building damage for global earthquake events: a proposed modelling approach

USGS Publications Warehouse

So, Emily; Spence, Robin

2013-01-01

Recent earthquakes such as the Haiti earthquake of 12 January 2010 and the Qinghai earthquake on 14 April 2010 have highlighted the importance of rapid estimation of casualties after the event for humanitarian response. Both of these events resulted in surprisingly high death tolls, casualties and survivors made homeless. In the Mw = 7.0 Haiti earthquake, over 200,000 people perished with more than 300,000 reported injuries and 2 million made homeless. The Mw = 6.9 earthquake in Qinghai resulted in over 2,000 deaths with a further 11,000 people with serious or moderate injuries and 100,000 people have been left homeless in this mountainous region of China. In such events relief efforts can be significantly benefitted by the availability of rapid estimation and mapping of expected casualties. This paper contributes to ongoing global efforts to estimate probable earthquake casualties very rapidly after an earthquake has taken place. The analysis uses the assembled empirical damage and casualty data in the Cambridge Earthquake Impacts Database (CEQID) and explores data by event and across events to test the relationships of building and fatality distributions to the main explanatory variables of building type, building damage level and earthquake intensity. The prototype global casualty estimation model described here uses a semi-empirical approach that estimates damage rates for different classes of buildings present in the local building stock, and then relates fatality rates to the damage rates of each class of buildings. This approach accounts for the effect of the very different types of buildings (by climatic zone, urban or rural location, culture, income level etc), on casualties. The resulting casualty parameters were tested against the overall casualty data from several historical earthquakes in CEQID; a reasonable fit was found.

The characteristic of the building damage from historical large earthquakes in Kyoto

NASA Astrophysics Data System (ADS)

Nishiyama, Akihito

2016-04-01

The Kyoto city, which is located in the northern part of Kyoto basin in Japan, has a long history of >1,200 years since the city was initially constructed. The city has been a populated area with many buildings and the center of the politics, economy and culture in Japan for nearly 1,000 years. Some of these buildings are now subscribed as the world's cultural heritage. The Kyoto city has experienced six damaging large earthquakes during the historical period: i.e., in 976, 1185, 1449, 1596, 1662, and 1830. Among these, the last three earthquakes which caused severe damage in Kyoto occurred during the period in which the urban area had expanded. These earthquakes are considered to be inland earthquakes which occurred around the Kyoto basin. The damage distribution in Kyoto from historical large earthquakes is strongly controlled by ground condition and earthquakes resistance of buildings rather than distance from estimated source fault. Therefore, it is necessary to consider not only the strength of ground shaking but also the condition of building such as elapsed years since the construction or last repair in order to more accurately and reliably estimate seismic intensity distribution from historical earthquakes in Kyoto. The obtained seismic intensity map would be helpful for reducing and mitigating disaster from future large earthquakes.

Application of τc*Pd in earthquake early warning

NASA Astrophysics Data System (ADS)

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

2015-03-01

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

Surficial geologic map of the Germantown quadrangle, Shelby County, Tennessee

USGS Publications Warehouse

Arsdale, Roy Van

2004-01-01

The depiction of geology on this map is designed to aid in urban planning and analysis of potential damage in the event of strong earthquake motion. The geologic map by itself does not analyze potential earthquake damage, but is designed to be used by seismologists who perform such analyses. The nature of geologic materials to a degree determines the severity of damage to infrastructure sustained during a strong earthquake.

Chapter C. The Loma Prieta, California, Earthquake of October 17, 1989 - Landslides

USGS Publications Warehouse

Keefer, David K.

1998-01-01

Central California, in the vicinity of San Francisco and Monterey Bays, has a history of fatal and damaging landslides, triggered by heavy rainfall, coastal and stream erosion, construction activity, and earthquakes. The great 1906 San Francisco earthquake (MS=8.2-8.3) generated more than 10,000 landslides throughout an area of 32,000 km2; these landslides killed at least 11 people and caused substantial damage to buildings, roads, railroads, and other civil works. Smaller numbers of landslides, which caused more localized damage, have also been reported from at least 20 other earthquakes that have occurred in the San Francisco Bay-Monterey Bay region since 1838. Conditions that make this region particularly susceptible to landslides include steep and rugged topography, weak rock and soil materials, seasonally heavy rainfall, and active seismicity. Given these conditions and history, it was no surprise that the 1989 Loma Prieta earthquake generated thousands of landslides throughout the region. Landslides caused one fatality and damaged at least 200 residences, numerous roads, and many other structures. Direct damage from landslides probably exceeded $30 million; additional, indirect economic losses were caused by long-term landslide blockage of two major highways and by delays in rebuilding brought about by concern over the potential long-term instability of some earthquake-damaged slopes.

Fluid Overpressure and Earthquakes Triggering in the Natural Laboratory of the Northern Apennines: Integration of Field and Laboratory Data

NASA Astrophysics Data System (ADS)

de Paola, N.; Collettini, C.; Faulkner, D.

2007-12-01

The integration of seismic reflection profiles with well-located earthquakes show that the mainshocks of the 1997-1998 Colfiorito seismic sequence (Central Italy) nucleated at a depth of ~6 km within the Triassic Evaporites (TE, anhydrites and dolostones), where CO2 at near lithostatic pressure has been encountered in two deep boreholes (4 km). In order to investigate the deformation processes operating at depth in the source region of the Colfiorito earthquakes we have characterized: 1) fault zone structure by studying exhumed outcrops of the temperature, 100 MPa confining pressure (Pc), and range of pore fluid pressures (Pf). Permeability and porosity development was continuously measured throughout the deformation experiments. The architecture of large fault zones within the TE is given by a distinct fault core, where most of the shear strain has been accommodated, surrounded by a geometrically complex and heterogeneous damage zone. Brittle deformation within the fault core is extremely localized along principal slip surfaces associated with dolomite rich cataclasite seams, running parallel to the fault zone. The damage zone is characterized by adjacent zones of heavily fractured rocks (dolostones) and foliated rocks displaying little fracturing (anhydrites). Static permeability measurements on anhydrite samples show increasing values of permeability for decreasing values of Pe, (k = 10E-20 - 10E-22 m2). During single cycle loading tests the permeability values immediately prior to failure are about three orders of magnitude higher than the initial values. The field data suggests that during the seismic cycle, the permeability of the dolostones, within the damage zone, is likely to be high and controlled by mesoscale fracture patterns. Conversely, the permeability of the anhydrites, due to the absence of mesoscale fracture patterns within Ca-sulphates layers, may be potentially as low as the values measured in the lab experiments (k = 10E-17 - 10E-22 m2). This suggests that fluid overpressure can be maintained in this lithology, within the damage zone, as far as the co-seismic period. Our observations and results can be applied to explain the seismicity of the Northern Apennines and other regions where fluids overpressures play a key role in triggering fault instability and earthquakes.

Fluid Overpressure and Earthquakes Triggering in the Natural Laboratory of the Northern Apennines: Integration of Field and Laboratory Data

NASA Astrophysics Data System (ADS)

de Paola, N.; Collettini, C.; Faulkner, D.

2004-12-01

The integration of seismic reflection profiles with well-located earthquakes show that the mainshocks of the 1997-1998 Colfiorito seismic sequence (Central Italy) nucleated at a depth of ~6 km within the Triassic Evaporites (TE, anhydrites and dolostones), where CO2 at near lithostatic pressure has been encountered in two deep boreholes (4 km). In order to investigate the deformation processes operating at depth in the source region of the Colfiorito earthquakes we have characterized: 1) fault zone structure by studying exhumed outcrops of the temperature, 100 MPa confining pressure (Pc), and range of pore fluid pressures (Pf). Permeability and porosity development was continuously measured throughout the deformation experiments. The architecture of large fault zones within the TE is given by a distinct fault core, where most of the shear strain has been accommodated, surrounded by a geometrically complex and heterogeneous damage zone. Brittle deformation within the fault core is extremely localized along principal slip surfaces associated with dolomite rich cataclasite seams, running parallel to the fault zone. The damage zone is characterized by adjacent zones of heavily fractured rocks (dolostones) and foliated rocks displaying little fracturing (anhydrites). Static permeability measurements on anhydrite samples show increasing values of permeability for decreasing values of Pe, (k = 10E-20 - 10E-22 m2). During single cycle loading tests the permeability values immediately prior to failure are about three orders of magnitude higher than the initial values. The field data suggests that during the seismic cycle, the permeability of the dolostones, within the damage zone, is likely to be high and controlled by mesoscale fracture patterns. Conversely, the permeability of the anhydrites, due to the absence of mesoscale fracture patterns within Ca-sulphates layers, may be potentially as low as the values measured in the lab experiments (k = 10E-17 - 10E-22 m2). This suggests that fluid overpressure can be maintained in this lithology, within the damage zone, as far as the co-seismic period. Our observations and results can be applied to explain the seismicity of the Northern Apennines and other regions where fluids overpressures play a key role in triggering fault instability and earthquakes.

LIDAR Investigation Of The 2004 Niigata Ken Chuetsu, Japan, Earthquake

NASA Astrophysics Data System (ADS)

Kayen, R.; Pack, R. T.; Sugimoto, S.; Tanaka, H.

2005-12-01

The 23 October 2004 Niigata Ken Chuetsu, Japan, Mw 6.6 earthquake was the most significant earthquake to affect Japan since the 1995 Kobe earthquake. Forty people were killed, almost 3,000 injured, and numerous landslides destroyed entire upland villages. Landslides and permanent ground deformation caused extensive damage to roads, rail lines and other lifelines, resulting in major economic disruption. The cities and towns most significantly affected by the earthquake were Nagaoka, Ojiya, and the mountainous rural areas of Yamakoshi village and Kawaguchi town. Our EERI team traveled with a tripod mounted LIDAR (Light Detection and Ranging) unit, a scanning-laser that creates ultra high-resolution 3-D digital terrain models of the earthquake damaged surfaces the ground, structures, and life-lines. This new technology allows for rapid and remote sensing of damaged terrain. Ground-based LIDAR has an accuracy range of 0.5-2.5 cm, and can illuminate targets up to 400m away from the sensor. During a single tripod-mounted LIDAR scan of 10 minutes, several million survey points are collected and processed into an ultra-high resolution terrain model of the damaged ground or structure. There are several benefits in acquiring these LIDAR data in the initial reconnaissance effort after the earthquake. First, we record the detailed failure morphologies of damaged ground and structures in order to make measurements that are either impractical or impossible by conventional survey means. The digital terrain models allow us to enlarge, enhance and rotate data in order to visualize damage in orientations and scales not previously possible. This ability to visualize damage allows us to better understand failure modes. Finally, LIDAR allows us to archive 3-D terrain models so that the engineering community can evaluate analytical and numerical models of deformation potential against detailed field measurements. Here, we discuss the findings of this 2004 Niigata Chuetsu Earthquake (M6.6) reconnaissance presented with LIDAR examples for damage-visualization.

April 25, 2015, Gorkha Earthquake, Nepal and Sequence of Aftershocks: Key Lessons

NASA Astrophysics Data System (ADS)

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

2015-12-01

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

Earthquakes and related catastrophic events, Island of Hawaii, November 29, 1975; a preliminary report

USGS Publications Warehouse

Tilling, Robert I.; Koyanagi, R.Y.; Lipman, P.W.; Lockwood, J.P.; Moore, J.G.; Swanson, D.A.

1976-01-01

The largest earthquake in over a century--magnitude 7.2 on the Richter Scale--struck Hawaii the morning of November 29, 1975, at 0448. It was centered about 5 km beneath the Kalapana area on the southeastern coast of the island at 19? 20.1 ' N., long 155? 01.4 ' W.). The earthquake was preceded by numerous foreshocks, the largest of which was a 5.7-magnitude jolt at 0336 the same morning, and was accompanied, or closely followed, by a tsunami seismic sea wave), massive ground movements, hundreds of aftershocks, and a volcanic eruption. The tsunami reached a height of 12.2-14.6 m above sea level on the southeastern coast about 25 km west of the earthquake center, elsewhere generally 8 m or less. The south flank of Kilauea Volcano, which forms the southeastern part of the island, was deformed by dislocations along old and new faults along a 25-km long zone. Downward and seaward fault displacements resulted in widespread subsidence, locally as much as 3.5 m, leaving coconut palms standing in the sea and nearly submerging a small, near-shore island. A brief, small-volume volcanic eruption, triggered by the earthquake and associated ground movements occurred at Kilauea's summit about three-quarters of an hour later. The earthquake, together with the tsunami it generated, locally caused severe property damage in the southeastern part of the island; the tsunami also caused two deaths. Damage from the earthquake and related catastrophic events is estimated by the Hawaii Civil Defense Agency at about $4.1 million. The 1975 Kalapana earthquake and accompanying events represent the latest events in a recurring pattern of behavior for Kilauea. A large earthquake of about the same magnitude, tsunami, subsidence, and eruption occurred at Kilauea in 1868, and a less powerful earthquake and similar related processes are believed to have occurred in 1823. Indeed, the geologic evidence suggests that such events have been repeated many times in Kilauea's past and will continue. The 1975 events serve as a critical, though tragic, reminder of the dynamic nature of the volcano and point up the need for careful land-use planning and adequate building codes to minimize damage and loss of life from similar events in the future. Detailed scientific study of the cause and effects of the November 29, 1975, event will take many months. This report summarizes information available in February 1976.

Study on the effect of the infill walls on the seismic performance of a reinforced concrete frame

NASA Astrophysics Data System (ADS)

Zhang, Cuiqiang; Zhou, Ying; Zhou, Deyuan; Lu, Xilin

2011-12-01

Motivated by the seismic damage observed to reinforced concrete (RC) frame structures during the Wenchuan earthquake, the effect of infill walls on the seismic performance of a RC frame is studied in this paper. Infill walls, especially those made of masonry, offer some amount of stiffness and strength. Therefore, the effect of infill walls should be considered during the design of RC frames. In this study, an analysis of the recorded ground motion in the Wenchuan earthquake is performed. Then, a numerical model is developed to simulate the infill walls. Finally, nonlinear dynamic analysis is carried out on a RC frame with and without infill walls, respectively, by using CANNY software. Through a comparative analysis, the following conclusions can be drawn. The failure mode of the frame with infill walls is in accordance with the seismic damage failure pattern, which is strong beam and weak column mode. This indicates that the infill walls change the failure pattern of the frame, and it is necessary to consider them in the seismic design of the RC frame. The numerical model presented in this paper can effectively simulate the effect of infill walls on the RC frame.

Strong ground motion in Port-au-Prince, Haiti, during the M7.0 12 January 2010 Haiti earthquake

USGS Publications Warehouse

Hough, Susan E; Given, Doug; Taniguchi, Tomoyo; Altidor, J.R.; Anglade, Dieuseul; Mildor, S-L.

2011-01-01

No strong motion records are available for the 12 January 2010 M7.0 Haiti earthquake. We use aftershock recordings as well as detailed considerations of damage to estimate the severity and distribution of mainshock shaking in Port-au-Prince. Relative to ground motions at a hard - rock reference site, peak accelerations are amplified by a factor of approximately 2 at sites on low-lying deposits in central Port-au-Prince and by a factor of 2.5 - 3.5 on a steep foothill ridge in the southern Port-au-Prince metropolitan region. The observed amplification along the ridge cannot be explained by sediment - induced amplification , but is consistent with predicted topographic amplification by a steep, narrow ridge. Although damage was largely a consequence of poor construction , the damage pattern inferred from analysis of remote sensing imagery provides evidence for a correspondence between small-scale (0.1 - 1.0 km) topographic relief and high damage. Mainshock shaking intensity can be estimated crudely from a consideration of macroseismic effects . We further present detailed, quantitative analysis of the marks left on a tile floor by an industrial battery rack displaced during the mainshock, at the location where we observed the highest weak motion amplifications. Results of this analysis indicate that mainshock shaking was significantly higher at this location (~0.5 g , MMI VIII) relative to the shaking in parts of Port-au-Prince that experienced light damage. Our results further illustrate how observations of rigid body horizontal displacement during earthquakes can be used to estimate peak ground accelerations in the absence of instrumental data .

Application of Remote Sensing in Building Damages Assessment after Moderate and Strong Earthquake

NASA Astrophysics Data System (ADS)

Tian, Y.; Zhang, J.; Dou, A.

2003-04-01

- Earthquake is a main natural disaster in modern society. However, we still cannot predict the time and place of its occurrence accurately. Then it is of much importance to survey the damages information when an earthquake occurs, which can help us to mitigate losses and implement fast damage evaluation. In this paper, we use remote sensing techniques for our purposes. Remotely sensed satellite images often view a large scale of land at a time. There are several kinds of satellite images, which of different spatial and spectral resolutions. Landsat-4/5 TM sensor can view ground at 30m resolution, while Landsat-7 ETM Plus has a resolution of 15m in panchromatic waveband. SPOT satellite can provide images with higher resolutions. Those images obtained pre- and post-earthquake can help us greatly in identifying damages of moderate and large-size buildings. In this paper, we bring forward a method to implement quick damages assessment by analyzing both pre- and post-earthquake satellite images. First, those images are geographically registered together with low RMS (Root Mean Square) error. Then, we clip out residential areas by overlaying images with existing vector layers through Geographic Information System (GIS) software. We present a new change detection algorithm to quantitatively identify damages degree. An empirical or semi-empirical model is then established by analyzing the real damage degree and changes of pixel values of the same ground objects. Experimental result shows that there is a good linear relationship between changes of pixel values and ground damages, which proves the potentials of remote sensing in post-quake fast damage assessment. Keywords: Damages Assessment, Earthquake Hazard, Remote Sensing

Earthquakes, July-August 1992

USGS Publications Warehouse

Person, W.J.

1992-01-01

There were two major earthquakes (7.0≤M<8.0) during this reporting period. A magnitude 7.5 earthquake occurred in Kyrgyzstan on August 19 and a magnitude 7.0 quake struck the Ascension Island region on August 28. In southern California, aftershocks of the magnitude 7.6 earthquake on June 28, 1992, continued. One of these aftershocks caused damage and injuries, and at least one other aftershock caused additional damage. Earthquake-related fatalities were reportred in Kyrgzstan and Pakistan. 

Aftershock risks such as those demonstrated by the recent events in New Zealand and Japan

USGS Publications Warehouse

Shome, Nilesh; Luco, Nicolas; Gerstenberger, Matt; Boyd, Oliver; Field, Edward; Liel, Abbie; van de Lindt, John W.

2014-01-01

Recent earthquakes in New Zealand and Japan show that it is important to consider the spatial and temporal distribution of aftershocks following large magnitude events since the probability of high intensity ground motions from aftershocks, which are capable of causing significant societal impact, can be considerable. This is due to the fact that a mainshock will have many aftershocks, some of which may occur closer to populated areas and may be large enough to cause damage. When a large magnitude event strikes a region, the chance that aftershocks will cause damage can be significant as was observed after the 2011 Tohoku and 2010 Canterbury earthquakes (e.g., damage caused by Mw6.6 April 11, 2011 Fukushima-Hamadori earthquake following Tohoku earthquake or by Mw6.3 February 22, 2011 Christchurch earthquake following Canterbury earthquake). Aftershock events may further damage already damaged buildings, thereby further complicating assessments of risk to the built environment. In this paper, the issue of aftershock risk is addressed by summarizing current research regarding: (1) aftershock hazard, (2) structural fragility/vulnerability before and after the mainshock, and (3) change in risk due to aftershocks.

Object-based classification of earthquake damage from high-resolution optical imagery using machine learning

NASA Astrophysics Data System (ADS)

Bialas, James; Oommen, Thomas; Rebbapragada, Umaa; Levin, Eugene

2016-07-01

Object-based approaches in the segmentation and classification of remotely sensed images yield more promising results compared to pixel-based approaches. However, the development of an object-based approach presents challenges in terms of algorithm selection and parameter tuning. Subjective methods are often used, but yield less than optimal results. Objective methods are warranted, especially for rapid deployment in time-sensitive applications, such as earthquake damage assessment. Herein, we used a systematic approach in evaluating object-based image segmentation and machine learning algorithms for the classification of earthquake damage in remotely sensed imagery. We tested a variety of algorithms and parameters on post-event aerial imagery for the 2011 earthquake in Christchurch, New Zealand. Results were compared against manually selected test cases representing different classes. In doing so, we can evaluate the effectiveness of the segmentation and classification of different classes and compare different levels of multistep image segmentations. Our classifier is compared against recent pixel-based and object-based classification studies for postevent imagery of earthquake damage. Our results show an improvement against both pixel-based and object-based methods for classifying earthquake damage in high resolution, post-event imagery.

Juan de Fuca slab geometry and its relation to Wadati-Benioff zone seismicity

USGS Publications Warehouse

McCrory, Patricia A.; Blair, J. Luke; Waldhause, Felix; Oppenheimer, David H.

2012-01-01

A new model of the subducted Juan de Fuca plate beneath western North America allows first-order correlations between the occurrence of Wadati-Benioff zone earthquakes and slab geometry, temperature, and hydration state. The geo-referenced 3D model, constructed from weighted control points, integrates depth information from earthquake locations and regional seismic velocity studies. We use the model to separate earthquakes that occur in the Cascadia forearc from those that occur within the underlying Juan de Fuca plate and thereby reveal previously obscured details regarding the spatial distribution of earthquakes. Seismicity within the slab is most prevalent where the slab is warped beneath northwestern California and western Washington suggesting that slab flexure, in addition to expected metamorphic dehydration processes, promotes earthquake occurrence within the subducted oceanic plate. Earthquake patterns beneath western Vancouver Island are consistent with slab dehydration processes. Conversely, the lack of slab earthquakes beneath western Oregon is consistent with an anhydrous slab. Double-differenced relocated seismicity resolves a double seismic zone within the slab beneath northwestern California that strongly constrains the location of the plate interface and delineates a cluster of seismicity 10 km above the surface that includes the 1992 M7.1 Mendocino earthquake. We infer that this earthquake ruptured a surface within the Cascadia accretionary margin above the Juan de Fuca plate. We further speculate that this earthquake is associated with a detached fragment of former Farallon plate. Other subsurface tectonic elements within the forearc may have the potential to generate similar damaging earthquakes.

Real-time earthquake shake, damage, and loss mapping for Istanbul metropolitan area

NASA Astrophysics Data System (ADS)

Zülfikar, A. Can; Fercan, N. Özge Zülfikar; Tunç, Süleyman; Erdik, Mustafa

2017-01-01

The past devastating earthquakes in densely populated urban centers, such as the 1994 Northridge; 1995 Kobe; 1999 series of Kocaeli, Düzce, and Athens; and 2011 Van-Erciş events, showed that substantial social and economic losses can be expected. Previous studies indicate that inadequate emergency response can increase the number of casualties by a maximum factor of 10, which suggests the need for research on rapid earthquake shaking damage and loss estimation. The reduction in casualties in urban areas immediately following an earthquake can be improved if the location and severity of damages can be rapidly assessed by information from rapid response systems. In this context, a research project (TUBITAK-109M734) titled "Real-time Information of Earthquake Shaking, Damage, and Losses for Target Cities of Thessaloniki and Istanbul" was conducted during 2011-2014 to establish the rapid estimation of ground motion shaking and related earthquake damages and casualties for the target cities. In the present study, application to Istanbul metropolitan area is presented. In order to fulfill this objective, earthquake hazard and risk assessment methodology known as Earthquake Loss Estimation Routine, which was developed for the Euro-Mediterranean region within the Network of Research Infrastructures for European Seismology EC-FP6 project, was used. The current application to the Istanbul metropolitan area provides real-time ground motion information obtained by strong motion stations distributed throughout the densely populated areas of the city. According to this ground motion information, building damage estimation is computed by using grid-based building inventory, and the related loss is then estimated. Through this application, the rapidly estimated information enables public and private emergency management authorities to take action and allocate and prioritize resources to minimize the casualties in urban areas during immediate post-earthquake periods. Moreover, it is expected that during an earthquake, rapid information of ground shaking, damage, and loss estimations will provide vital information to allow appropriate emergency agencies to take immediate action, which will help to save lives. In general terms, this study can be considered as an example for application to metropolitan areas under seismic risk.

Make an Earthquake: Ground Shaking!

ERIC Educational Resources Information Center

Savasci, Funda

2011-01-01

The main purposes of this activity are to help students explore possible factors affecting the extent of the damage of earthquakes and learn the ways to reduce earthquake damages. In these inquiry-based activities, students have opportunities to develop science process skills and to build an understanding of the relationship among science,…

The magnitude 6.7 Northridge, California, earthquake of 17 January 1994

USGS Publications Warehouse

Jones, L.; Aki, K.; Boore, D.; Celebi, M.; Donnellan, A.; Hall, J.; Harris, R.; Hauksson, E.; Heaton, T.; Hough, S.; Hudnut, K.; Hutton, K.; Johnston, M.; Joyner, W.; Kanamori, H.; Marshall, G.; Michael, A.; Mori, J.; Murray, M.; Ponti, D.; Reasenberg, P.; Schwartz, D.; Seeber, L.; Shakal, A.; Simpson, R.; Thio, H.; Tinsley, J.; Todorovska, M.; Trifunac, M.; Wald, D.; Zoback, M.L.

1994-01-01

The most costly American earthquake since 1906 struck Los Angeles on 17 January 1994. The magnitude 6.7 Northridge earthquake resulted from more than 3 meters of reverse slip on a 15-kilometer-long south-dipping thrust fault that raised the Santa Susana mountains by as much as 70 centimeters. The fault appears to be truncated by the fault that broke in the 1971 San Fernando earthquake at a depth of 8 kilometers. Of these two events, the Northridge earthquake caused many times more damage, primarily because its causative fault is directly under the city. Many types of structures were damaged, but the fracture of welds in steel-frame buildings was the greatest surprise. The Northridge earthquake emphasizes the hazard posed to Los Angeles by concealed thrust faults and the potential for strong ground shaking in moderate earthquakes.The most costly American earthquake since 1906 struck Los Angeles on 17 January 1994. The magnitude 6.7 Northridge earthquake resulted from more than 3 meters of reverse slip on a 15-kilometer-long south-dipping thrust fault that raised the Santa Susana mountains by as much as 70 centimeters. The fault appears to be truncated by the fault that broke in the 1971 San Fernando earthquake at a depth of 8 kilometers. Of these two events, the Northridge earthquake caused many times more damage, primarily because its causative fault is directly under the city. Many types of structures were damaged, but the fracture of welds in steel-frame buildings was the greatest surprise. The Northridge earthquake emphasizes the hazard posed to Los Angeles by concealed thrust faults and the potential for strong ground shaking in moderate earthquakes.

Hazus® estimated annualized earthquake losses for the United States

USGS Publications Warehouse

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

2017-01-01

Large earthquakes can cause social and economic disruption that can be unprecedented to any given community, and the full recovery from these impacts may or may not always be achievable. In the United States (U.S.), the 1994 M6.7 Northridge earthquake in California remains the third costliest disaster in U.S. history; and it was one of the most expensive disasters for the federal government. Internationally, earthquakes in the last decade alone have claimed tens of thousands of lives and caused hundreds of billions of dollars of economic impact throughout the globe (~90 billion U.S. dollars (USD) from 2008 M7.9 Wenchuan China, ~20 billion USD from 2010 M8.8 Maule earthquake in Chile, ~220 billion USD from 2011 M9.0 Tohoku Japan earthquake, ~25 billion USD from 2011 M6.3 Christchurch New Zealand, and ~22 billion USD from 2016 M7.0 Kumamoto Japan). Recent earthquakes show a pattern of steadily increasing damages and losses that are primarily due to three key factors: (1) significant growth in earthquake-prone urban areas, (2) vulnerability of the older building stock, including poorly engineered non-ductile concrete buildings, and (3) an increased interdependency in terms of supply and demand for the businesses that operate among different parts of the world. In the United States, earthquake risk continues to grow with increased exposure of population and development even though the earthquake hazard has remained relatively stable except for the regions of induced seismic activity. Understanding the seismic hazard requires studying earthquake characteristics and locales in which they occur, while understanding the risk requires an assessment of the potential damage from earthquake shaking to the built environment and to the welfare of people—especially in high-risk areas. Estimating the varying degree of earthquake risk throughout the United States is critical for informed decision-making on mitigation policies, priorities, strategies, and funding levels in the public and private sectors. For example, potential losses to new buildings may be reduced by proper land-use planning, applying most current seismic design codes and using new technologies and specialized construction techniques. However, decisions to spend money on any of those solutions require benefit and cost comparison against the perceived risk. Previous versions of the FEMA 366 studies are the only nationally accepted criteria and methodology for comparing seismic risk across regions.

Global Omori law decay of triggered earthquakes: large aftershocks outside the classical aftershock zone

USGS Publications Warehouse

Parsons, Tom

2002-01-01

Triggered earthquakes can be large, damaging, and lethal as evidenced by the 1999 shocks in Turkey and the 2001 earthquakes in El Salvador. In this study, earthquakes with Ms ≥ 7.0 from the Harvard centroid moment tensor (CMT) catalog are modeled as dislocations to calculate shear stress changes on subsequent earthquake rupture planes near enough to be affected. About 61% of earthquakes that occurred near (defined as having shear stress change ∣Δτ∣ ≥ 0.01 MPa) the Ms ≥ 7.0 shocks are associated with calculated shear stress increases, while ∼39% are associated with shear stress decreases. If earthquakes associated with calculated shear stress increases are interpreted as triggered, then such events make up at least 8% of the CMT catalog. Globally, these triggered earthquakes obey an Omori law rate decay that lasts between ∼7–11 years after the main shock. Earthquakes associated with calculated shear stress increases occur at higher rates than background up to 240 km away from the main shock centroid. Omori's law is one of the few time-predictable patterns evident in the global occurrence of earthquakes. If large triggered earthquakes habitually obey Omori's law, then their hazard can be more readily assessed. The characteristic rate change with time and spatial distribution can be used to rapidly assess the likelihood of triggered earthquakes following events of Ms ≥ 7.0. I show an example application to the M = 7.7 13 January 2001 El Salvador earthquake where use of global statistics appears to provide a better rapid hazard estimate than Coulomb stress change calculations.

Global Omori law decay of triggered earthquakes: Large aftershocks outside the classical aftershock zone

USGS Publications Warehouse

Parsons, T.

2002-01-01

Triggered earthquakes can be large, damaging, and lethal as evidenced by the 1999 shocks in Turkey and the 2001 earthquakes in El Salvador. In this study, earthquakes with Ms ≥ 7.0 from the Harvard centroid moment tensor (CMT) catalog are modeled as dislocations to calculate shear stress changes on subsequent earthquake rupture planes near enough to be affected. About 61% of earthquakes that occured near (defined as having shear stress change |Δ| 0.01 MPa) the Ms ≥ 7.0 shocks are associated with calculated shear stress increases, while ~39% are associated with shear stress decreases. If earthquakes associated with calculated shear stress increases are interpreted as triggered, then such events make up at least 8% of the CMT catalog. Globally, these triggered earthquakes obey an Omori law rate decay that lasts between ~7-11 years after the main shock. Earthquakes associated with calculated shear stress increases occur at higher rates than background up to 240 km away from the main shock centroid. Omori's law is one of the few time-predictable patterns evident in the global occurrence of earthquakes. If large triggered earthquakes habitually obey Omori's law, then their hazard can be more readily assessed. The characteristics rate change with time and spatial distribution can be used to rapidly assess the likelihood of triggered earthquakes following events of Ms ≥7.0. I show an example application to the M = 7.7 13 January 2001 El Salvador earthquake where use of global statistics appears to provide a better rapid hazard estimate than Coulomb stress change calculations.

Global Omori law decay of triggered earthquakes: Large aftershocks outside the classical aftershock zone

NASA Astrophysics Data System (ADS)

Parsons, Tom

2002-09-01

Triggered earthquakes can be large, damaging, and lethal as evidenced by the1999 shocks in Turkey and the 2001 earthquakes in El Salvador. In this study, earthquakes with Ms ≥ 7.0 from the Harvard centroid moment tensor (CMT) catalog are modeled as dislocations to calculate shear stress changes on subsequent earthquake rupture planes near enough to be affected. About 61% of earthquakes that occurred near (defined as having shear stress change ∣Δτ∣ ≥ 0.01 MPa) the Ms ≥ 7.0 shocks are associated with calculated shear stress increases, while ˜39% are associated with shear stress decreases. If earthquakes associated with calculated shear stress increases are interpreted as triggered, then such events make up at least 8% of the CMT catalog. Globally, these triggered earthquakes obey an Omori law rate decay that lasts between ˜7-11 years after the main shock. Earthquakes associated with calculated shear stress increases occur at higher rates than background up to 240 km away from the main shock centroid. Omori's law is one of the few time-predictable patterns evident in the global occurrence of earthquakes. If large triggered earthquakes habitually obey Omori's law, then their hazard can be more readily assessed. The characteristic rate change with time and spatial distribution can be used to rapidly assess the likelihood of triggered earthquakes following events of Ms ≥ 7.0. I show an example application to the M = 7.7 13 January 2001 El Salvador earthquake where use of global statistics appears to provide a better rapid hazard estimate than Coulomb stress change calculations.

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

NASA Technical Reports Server (NTRS)

Oommen, Thomas; Rebbapragada, Umaa; Cerminaro, Daniel

2012-01-01

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

Strength, functionality and beauty of university buildings in earthquake-prone countries

PubMed Central

WADA, Akira

2018-01-01

Strength, functionality and beauty are the three qualities identifying well-designed architecture. For buildings in earthquake-prone countries such as Japan, emphasis on seismic safety frequently leads to the sacrifice of functionality and beauty. Therefore, it is important to develop new structural technologies that can ensure the seismic performance of a building without hampering the pursuit of functionality and beauty. The moment-resisting frame structures widely used for buildings in Japan are likely to experience weak-story collapse. Pin-supported walls, which can effectively enhance the structural story-by-story integrity of a building, were introduced to prevent such an unfavorable failure pattern in the seismic retrofit of an eleven-story building on a university campus in Tokyo, while also greatly aesthetically enhancing the façade of the building. The slight damage observed and monitoring records of the retrofitted building during the 2011 Tohoku earthquake in Japan demonstrate that the pin-supported walls worked as intended, protecting the building and guaranteeing the safety of its occupants during the earthquake. PMID:29434079

Surface-seismic imaging for nehrp soil profile classifications and earthquake hazards in urban areas

USGS Publications Warehouse

Williams, R.A.; Stephenson, W.J.; Odum, J.K.

1998-01-01

We acquired high-resolution seismic-refraction data on the ground surface in selected areas of the San Fernando Valley (SFV) to help explain the earthquake damage patterns and the variation in ground motion caused by the 17 January 1994 magnitude 6.7 Northridge earthquake. We used these data to determine the compressional- and shear-wave velocities (Vp and Vs) at 20 aftershock recording sites to 30-m depth ( V??s30, and V??p30). Two other sites, located next to boreholes with downhole Vp and Vs data, show that we imaged very similar seismic-vefocity structures in the upper 40 m. Overall, high site response appears to be associated with tow Vs in the near surface, but there can be a wide rangepf site amplifications for a given NEHRP soil type. The data suggest that for the SFV, if the V??s30 is known, we can determine whether the earthquake ground motion will be amplified above a factor of 2 relative to a local rock site.

Archaeoseismology in Algeria: observed damages related to probable past earthquakes on archaeological remains on Roman sites (Tel Atlas of Algeria)

NASA Astrophysics Data System (ADS)

Roumane, Kahina; Ayadi, Abdelhakim

2017-04-01

The seismological catalogue for Algeria exhibits significant lack for the period before 1365. Some attempts led to retrieve ancient earthquakes evidenced by historical documents and achieves. Archaeoseismology allows a study of earthquakes that have affected archaeological sites, based on the analysis of damage observed on remains. We have focused on the Antiquity period that include Roman, Vandal and Byzantine period from B.C 146 to A.D. 533. This will contribute significantly to the understanding of seismic hazard of the Tell Atlas region known as an earthquake prone area. The Tell Atlas (Algeria) experienced during its history many disastrous earthquakes their impacts are graved on landscape and archaeological monuments. On Roman sites such, Lambaesis (Lambèse), Thamugadi (Timgad) Thibilis (Salaoua Announa) or Thevest (Tebessa), damage were observed on monuments and remains related to seismic events following strong shacking or other ground deformation (subsidence, landslide). Examples of observed damage and disorders on several Roman sites are presented as a contribution to Archaeoseismology in Algeria based on effects of earthquakes on ancient structures and monuments. Keywords : Archaeoseismology. Lambaesis. Drop columns. Aspecelium. Ancient earthquakes

Effects of Aftershock Declustering in Risk Modeling: Case Study of a Subduction Sequence in Mexico

NASA Astrophysics Data System (ADS)

Kane, D. L.; Nyst, M.

2014-12-01

Earthquake hazard and risk models often assume that earthquake rates can be represented by a stationary Poisson process, and that aftershocks observed in historical seismicity catalogs represent a deviation from stationarity that must be corrected before earthquake rates are estimated. Algorithms for classifying individual earthquakes as independent mainshocks or as aftershocks vary widely, and analysis of a single catalog can produce considerably different earthquake rates depending on the declustering method implemented. As these rates are propagated through hazard and risk models, the modeled results will vary due to the assumptions implied by these choices. In particular, the removal of large aftershocks following a mainshock may lead to an underestimation of the rate of damaging earthquakes and potential damage due to a large aftershock may be excluded from the model. We present a case study based on the 1907 - 1911 sequence of nine 6.9 <= Mw <= 7.9 earthquakes along the Cocos - North American plate subduction boundary in Mexico in order to illustrate the variability in risk under various declustering approaches. Previous studies have suggested that subduction zone earthquakes in Mexico tend to occur in clusters, and this particular sequence includes events that would be labeled as aftershocks in some declustering approaches yet are large enough to produce significant damage. We model the ground motion for each event, determine damage ratios using modern exposure data, and then compare the variability in the modeled damage from using the full catalog or one of several declustered catalogs containing only "independent" events. We also consider the effects of progressive damage caused by each subsequent event and how this might increase or decrease the total losses expected from this sequence.

Near-surface versus fault zone damage following the 1999 Chi-Chi earthquake: Observation and simulation of repeating earthquakes

USGS Publications Warehouse

Chen, Kate Huihsuan; Furumura, Takashi; Rubinstein, Justin L.

2015-01-01

We observe crustal damage and its subsequent recovery caused by the 1999 M7.6 Chi-Chi earthquake in central Taiwan. Analysis of repeating earthquakes in Hualien region, ~70 km east of the Chi-Chi earthquake, shows a remarkable change in wave propagation beginning in the year 2000, revealing damage within the fault zone and distributed across the near surface. We use moving window cross correlation to identify a dramatic decrease in the waveform similarity and delays in the S wave coda. The maximum delay is up to 59 ms, corresponding to a 7.6% velocity decrease averaged over the wave propagation path. The waveform changes on either side of the fault are distinct. They occur in different parts of the waveforms, affect different frequencies, and the size of the velocity reductions is different. Using a finite difference method, we simulate the effect of postseismic changes in the wavefield by introducing S wave velocity anomaly in the fault zone and near the surface. The models that best fit the observations point to pervasive damage in the near surface and deep, along-fault damage at the time of the Chi-Chi earthquake. The footwall stations show the combined effect of near-surface and the fault zone damage, where the velocity reduction (2–7%) is twofold to threefold greater than the fault zone damage observed in the hanging wall stations. The physical models obtained here allow us to monitor the temporal evolution and recovering process of the Chi-Chi fault zone damage.

Calibration and validation of earthquake catastrophe models. Case study: Impact Forecasting Earthquake Model for Algeria

NASA Astrophysics Data System (ADS)

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

2012-04-01

Calibration and validation are crucial steps in the production of the catastrophe models for the insurance industry in order to assure the model's reliability and to quantify its uncertainty. Calibration is needed in all components of model development including hazard and vulnerability. Validation is required to ensure that the losses calculated by the model match those observed in past events and which could happen in future. Impact Forecasting, the catastrophe modelling development centre of excellence within Aon Benfield, has recently launched its earthquake model for Algeria as a part of the earthquake model for the Maghreb region. The earthquake model went through a detailed calibration process including: (1) the seismic intensity attenuation model by use of macroseismic observations and maps from past earthquakes in Algeria; (2) calculation of the country-specific vulnerability modifiers by use of past damage observations in the country. The use of Benouar, 1994 ground motion prediction relationship was proven as the most appropriate for our model. Calculation of the regional vulnerability modifiers for the country led to 10% to 40% larger vulnerability indexes for different building types compared to average European indexes. The country specific damage models also included aggregate damage models for residential, commercial and industrial properties considering the description of the buildings stock given by World Housing Encyclopaedia and the local rebuilding cost factors equal to 10% for damage grade 1, 20% for damage grade 2, 35% for damage grade 3, 75% for damage grade 4 and 100% for damage grade 5. The damage grades comply with the European Macroseismic Scale (EMS-1998). The model was validated by use of "as-if" historical scenario simulations of three past earthquake events in Algeria M6.8 2003 Boumerdes, M7.3 1980 El-Asnam and M7.3 1856 Djidjelli earthquake. The calculated return periods of the losses for client market portfolio align with the repeatability of such catastrophe losses in the country. The validation process also included collaboration between Aon Benfield and its client in order to consider the insurance market penetration in Algeria estimated approximately at 5%. Thus, we believe that the applied approach led towards the production of an earthquake model for Algeria that is scientifically sound and reliable from one side and market and client oriented on the other side.

Estimation of vulnerability functions based on a global earthquake damage database

NASA Astrophysics Data System (ADS)

Spence, R. J. S.; Coburn, A. W.; Ruffle, S. J.

2009-04-01

Developing a better approach to the estimation of future earthquake losses, and in particular to the understanding of the inherent uncertainties in loss models, is vital to confidence in modelling potential losses in insurance or for mitigation. For most areas of the world there is currently insufficient knowledge of the current building stock for vulnerability estimates to be based on calculations of structural performance. In such areas, the most reliable basis for estimating vulnerability is performance of the building stock in past earthquakes, using damage databases, and comparison with consistent estimates of ground motion. This paper will present a new approach to the estimation of vulnerabilities using the recently launched Cambridge University Damage Database (CUEDD). CUEDD is based on data assembled by the Martin Centre at Cambridge University since 1980, complemented by other more-recently published and some unpublished data. The database assembles in a single, organised, expandable and web-accessible database, summary information on worldwide post-earthquake building damage surveys which have been carried out since the 1960's. Currently it contains data on the performance of more than 750,000 individual buildings, in 200 surveys following 40 separate earthquakes. The database includes building typologies, damage levels, location of each survey. It is mounted on a GIS mapping system and links to the USGS Shakemaps of each earthquake which enables the macroseismic intensity and other ground motion parameters to be defined for each survey and location. Fields of data for each building damage survey include: · Basic earthquake data and its sources · Details of the survey location and intensity and other ground motion observations or assignments at that location · Building and damage level classification, and tabulated damage survey results · Photos showing typical examples of damage. In future planned extensions of the database information on human casualties will also be assembled. The database also contains analytical tools enabling data from similar locations, building classes or ground motion levels to be assembled and thus vulnerability relationships derived for any chosen ground motion parameter, for a given class of building, and for particular countries or regions. The paper presents examples of vulnerability relationships for particular classes of buildings and regions of the world, together with the estimated uncertainty ranges. It will discuss the applicability of such vulnerability functions in earthquake loss assessment for insurance purposes or for earthquake risk mitigation.

Determine Earthquake Rupture Directivity Using Taiwan TSMIP Strong Motion Waveforms

NASA Astrophysics Data System (ADS)

Chang, Kaiwen; Chi, Wu-Cheng; Lai, Ying-Ju; Gung, YuanCheng

2013-04-01

Inverting seismic waveforms for the finite fault source parameters is important for studying the physics of earthquake rupture processes. It is also significant to image seismogenic structures in urban areas. Here we analyze the finite-source process and test for the causative fault plane using the accelerograms recorded by the Taiwan Strong-Motion Instrumentation Program (TSMIP) stations. The point source parameters for the mainshock and aftershocks were first obtained by complete waveform moment tensor inversions. We then use the seismograms generated by the aftershocks as empirical Green's functions (EGFs) to retrieve the apparent source time functions (ASTFs) of near-field stations using projected Landweber deconvolution approach. The method for identifying the fault plane relies on the spatial patterns of the apparent source time function durations which depend on the angle between rupture direction and the take-off angle and azimuth of the ray. These derived duration patterns then are compared with the theoretical patterns, which are functions of the following parameters, including focal depth, epicentral distance, average crustal 1D velocity, fault plane attitude, and rupture direction on the fault plane. As a result, the ASTFs derived from EGFs can be used to infer the ruptured fault plane and the rupture direction. Finally we used part of the catalogs to study important seismogenic structures in the area near Chiayi, Taiwan, where a damaging earthquake has occurred about a century ago. The preliminary results show a strike-slip earthquake on 22 October 1999 (Mw 5.6) has ruptured unilaterally toward SSW on a sub-vertical fault. The procedure developed from this study can be applied to other strong motion waveforms recorded from other earthquakes to better understand their kinematic source parameters.

Evidence for Ancient Mesoamerican Earthquakes

NASA Astrophysics Data System (ADS)

Kovach, R. L.; Garcia, B.

2001-12-01

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

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

NASA Astrophysics Data System (ADS)

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

2014-05-01

Among the many kinds of natural and man-made disasters, earthquakes dominate with regard to their social and economical impact on the urban environment. Global seismic risk to earthquakes are increasing steadily as urbanization and development occupy more areas that a prone to effects of strong earthquakes. Additionally, the uncontrolled growth of mega cities in highly seismic areas around the world is often associated with the construction of seismically unsafe buildings and infrastructures, and undertaken with an insufficient knowledge of the regional seismicity peculiarities and seismic hazard. The assessment of seismic hazard and generation of earthquake scenarios is the first link in the prevention chain and the first step in the evaluation of the seismic risk. The earthquake scenarios are intended as a basic input for developing detailed earthquake damage scenarios for the cities and can be used in earthquake-safe town and infrastructure planning. The city of Sofia is the capital of Bulgaria. It is situated in the centre of the Sofia area that is the most populated (the population is of more than 1.2 mil. inhabitants), industrial and cultural region of Bulgaria that faces considerable earthquake risk. The available historical documents prove the occurrence of destructive earthquakes during the 15th-18th centuries in the Sofia zone. In 19th century the city of Sofia has experienced two strong earthquakes: the 1818 earthquake with epicentral intensity I0=8-9 MSK and the 1858 earthquake with I0=9-10 MSK. During the 20th century the strongest event occurred in the vicinity of the city of Sofia is the 1917 earthquake with MS=5.3 (I0=7-8 MSK). Almost a century later (95 years) an earthquake of moment magnitude 5.6 (I0=7-8 MSK) hit the city of Sofia, on May 22nd, 2012. In the present study as a deterministic scenario event is considered a damaging earthquake with higher probability of occurrence that could affect the city with intensity less than or equal to VIII. The usable and realistic ground motion maps for urban areas are generated: - either from the assumption of a "reference earthquake" - or directly, showing values of macroseimic intensity generated by a damaging, real earthquake. In the study, applying deterministic approach, earthquake scenario in macroseismic intensity ("model" earthquake scenario) for the city of Sofia is generated. The deterministic "model" intensity scenario based on assumption of a "reference earthquake" is compared with a scenario based on observed macroseimic effects caused by the damaging 2012 earthquake (MW5.6). The difference between observed (Io) and predicted (Ip) intensities values is analyzed.

Source parameters of the 2014 Ms6.5 Ludian earthquake sequence and their implications on the seismogenic structure

NASA Astrophysics Data System (ADS)

Zheng, Y.

2015-12-01

On August 3, 2014, an Ms6.5 earthquake struck Ludian county, Zhaotong city in Yunnan province, China. Although this earthquake is not very big, it caused abnormal severe damages. Thus, study on the causes of the serious damages of this moderate strong earthquake may help us to evaluate seismic hazards for similar earthquakes. Besides the factors which directly relate to the damages, such as site effects, quality of buildings, seismogenic structures and the characteristics of the mainshock and the aftershocks may also responsible for the seismic hazards. Since focal mechanism solution and centroid depth provide key information of earthquake source properties and tectonic stress field, and the focal depth is one of the most important parameters which control the damages of earthquakes, obtaining precise FMSs and focal depths of the Ludian earthquake sequence may help us to determine the detailed geometric features of the rupture fault and the seismogenic environment. In this work we obtained the FMSs and centroid depths of the Ludian earthquake and its Ms>3.0 aftershocks by the revised CAP method, and further verified some focal depths using the depth phase method. Combining the FMSs of the mainshock and the strong aftershocks, as well as their spatial distributions, and the seismogenic environment of the source region, we can make the following characteristics of the Ludian earthquake sequence and its seismogenic structure: (1) The Ludian earthquake is a left-lateral strike slip earthquake, with magnitude of about Mw6.1. The FMS of nodal plane I is 75o/56o/180o for strike, dip and rake angles, and 165o/90o/34ofor the other nodal plane. (2) The Ludian earthquake is very shallow with the optimum centroid depth of ~3 km, which is consistent with the strong ground shaking and the surface rupture observed by field survey and strengthens the damages of the Ludian earthquake. (3) The Ludian Earthquake should occur on the NNW trend BXF. Because two later aftershocks occurred close to the fault zone of the ZLF, and their FMSs are similar with the characteristics of the ZLF, the shallower part of the ZLF may also rupture during the aftershock duration of the Ludian earthquake. Since the ZLF is much longer than the BXF, the seismic risk of the ZLF may be high and should be required more attention.

Earthquake Damage Assessment Using Very High Resolution Satelliteimagery

NASA Astrophysics Data System (ADS)

Chiroiu, L.; André, G.; Bahoken, F.; Guillande, R.

Various studies using satellite imagery were applied in the last years in order to assess natural hazard damages, most of them analyzing the case of floods, hurricanes or landslides. For the case of earthquakes, the medium or small spatial resolution data available in the recent past did not allow a reliable identification of damages, due to the size of the elements (e.g. buildings or other structures), too small compared with the pixel size. The recent progresses of remote sensing in terms of spatial resolution and data processing makes possible a reliable damage detection to the elements at risk. Remote sensing techniques applied to IKONOS (1 meter resolution) and IRS (5 meters resolution) imagery were used in order to evaluate seismic vulnerability and post earthquake damages. A fast estimation of losses was performed using a multidisciplinary approach based on earthquake engineering and geospatial analysis. The results, integrated into a GIS database, could be transferred via satellite networks to the rescue teams deployed on the affected zone, in order to better coordinate the emergency operations. The methodology was applied to the city of Bhuj and Anjar after the 2001 Gujarat (India) Earthquake.

Liquefaction-induced lateral spreading in Oceano, California, during the 2003 San Simeon Earthquake

USGS Publications Warehouse

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

2004-01-01

The December 22, 2003, San Simeon, California, (M6.5) earthquake caused damage to houses, road surfaces, and underground utilities in Oceano, California. The community of Oceano is approximately 50 miles (80 km) from the earthquake epicenter. Damage at this distance from a M6.5 earthquake is unusual. To understand the causes of this damage, the U.S. Geological Survey conducted extensive subsurface exploration and monitoring of aftershocks in the months after the earthquake. The investigation included 37 seismic cone penetration tests, 5 soil borings, and aftershock monitoring from January 28 to March 7, 2004. The USGS investigation identified two earthquake hazards in Oceano that explain the San Simeon earthquake damage?site amplification and liquefaction. Site amplification is a phenomenon observed in many earthquakes where the strength of the shaking increases abnormally in areas where the seismic-wave velocity of shallow geologic layers is low. As a result, earthquake shaking is felt more strongly than in surrounding areas without similar geologic conditions. Site amplification in Oceano is indicated by the physical properties of the geologic layers beneath Oceano and was confirmed by monitoring aftershocks. Liquefaction, which is also commonly observed during earthquakes, is a phenomenon where saturated sands lose their strength during an earthquake and become fluid-like and mobile. As a result, the ground may undergo large permanent displacements that can damage underground utilities and well-built surface structures. The type of displacement of major concern associated with liquefaction is lateral spreading because it involves displacement of large blocks of ground down gentle slopes or towards stream channels. The USGS investigation indicates that the shallow geologic units beneath Oceano are very susceptible to liquefaction. They include young sand dunes and clean sandy artificial fill that was used to bury and convert marshes into developable lots. Most of the 2003 damage was caused by lateral spreading in two separate areas, one near Norswing Drive and the other near Juanita Avenue. The areas coincided with areas with the highest liquefaction potential found in Oceano. Areas with site amplification conditions similar to those in Oceano are particularly vulnerable to earthquakes. Site amplification may cause shaking from distant earthquakes, which normally would not cause damage, to increase locally to damaging levels. The vulnerability in Oceano is compounded by the widespread distribution of highly liquefiable soils that will reliquefy when ground shaking is amplified as it was during the San Simeon earthquake. The experience in Oceano can be expected to repeat because the region has many active faults capable of generating large earthquakes. In addition, liquefaction and lateral spreading will be more extensive for moderate-size earthquakes that are closer to Oceano than was the 2003 San Simeon earthquake. Site amplification and liquefaction can be mitigated. Shaking is typically mitigated in California by adopting and enforcing up-to-date building codes. Although not a guarantee of safety, application of these codes ensures that the best practice is used in construction. Building codes, however, do not always require the upgrading of older structures to new code requirements. Consequently, many older structures may not be as resistant to earthquake shaking as new ones. For older structures, retrofitting is required to bring them up to code. Seismic provisions in codes also generally do not apply to nonstructural elements such as drywall, heating systems, and shelving. Frequently, nonstructural damage dominates the earthquake loss. Mitigation of potential liquefaction in Oceano presently is voluntary for existing buildings, but required by San Luis Obispo County for new construction. Multiple mitigation procedures are available to individual property owners. These procedures typically involve either

Chapter B. The Loma Prieta, California, Earthquake of October 17, 1989 - Highway Systems

USGS Publications Warehouse

Yashinsky, Mark

1998-01-01

This paper summarizes the impact of the Loma Prieta earthquake on highway systems. City streets, urban freeways, county roads, state routes, and the national highway system were all affected. There was damage to bridges, roads, tunnels, and other highway structures. The most serious damage occurred in the cities of San Francisco and Oakland, 60 miles from the fault rupture. The cost to repair and replace highways damaged by this earthquake was $2 billion. About half of this cost was to replace the Cypress Viaduct, a long, elevated double-deck expressway that had a devastating collapse which resulted in 42 deaths and 108 injuries. The earthquake also resulted in some positive changes for highway systems. Research on bridges and earthquakes began to be funded at a much higher level. Retrofit programs were started to upgrade the seismic performance of the nation's highways. The Loma Prieta earthquake changed earthquake policy and engineering practice for highway departments not only in California, but all over the world.

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

NASA Astrophysics Data System (ADS)

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

2014-12-01

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

Demand surge following earthquakes

USGS Publications Warehouse

Olsen, Anna H.

2012-01-01

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

Global Instrumental Seismic Catalog: earthquake relocations for 1900-present

NASA Astrophysics Data System (ADS)

Villasenor, A.; Engdahl, E.; Storchak, D. A.; Bondar, I.

2010-12-01

We present the current status of our efforts to produce a set of homogeneous earthquake locations and improved focal depths towards the compilation of a Global Catalog of instrumentally recorded earthquakes that will be complete down to the lowest magnitude threshold possible on a global scale and for the time period considered. This project is currently being carried out under the auspices of GEM (Global Earthquake Model). The resulting earthquake catalog will be a fundamental dataset not only for earthquake risk modeling and assessment on a global scale, but also for a large number of studies such as global and regional seismotectonics; the rupture zones and return time of large, damaging earthquakes; the spatial-temporal pattern of moment release along seismic zones and faults etc. Our current goal is to re-locate all earthquakes with available station arrival data using the following magnitude thresholds: M5.5 for 1964-present, M6.25 for 1918-1963, M7.5 (complemented with significant events in continental regions) for 1900-1917. Phase arrival time data for earthquakes after 1963 are available in digital form from the International Seismological Centre (ISC). For earthquakes in the time period 1918-1963, phase data is obtained by scanning the printed International Seismological Summary (ISS) bulletins and applying optical character recognition routines. For earlier earthquakes we will collect phase data from individual station bulletins. We will illustrate some of the most significant results of this relocation effort, including aftershock distributions for large earthquakes, systematic differences in epicenter and depth with respect to previous location, examples of grossly mislocated events, etc.

Earthquake risk assessment of Alexandria, Egypt

NASA Astrophysics Data System (ADS)

Badawy, Ahmed; Gaber, Hanan; Ibrahim, Hamza

2015-01-01

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

Rupture directivity and local site effects: the M7.3 Honduras earthquake of May 23, 2009

NASA Astrophysics Data System (ADS)

Shulman, D.; Mooney, W. D.

2009-12-01

On May 28, 2009, at 2:24 AM local time, a M 7.3 earthquake struck off the coast of Honduras on the Motagua-Swan Fault System (MSFS), part of the boundary between the North America and Caribbean plates. This plate boundary has an average slip rate of 20 mm/year. This left-lateral earthquake had an average slip of 1.5 m on a 100-km-long near-vertical fault plane (Hayes and Ji, 2009). The hypocenter depth is estimated at 10 km. The main shock caused 130 structures, including homes and office buildings, to collapse or suffer significant damage in northern Honduras. Seven deaths were reported. Due to a lack of recordings in the area, the available documentation of the local effects of this earthquake are the USGS "Did you feel it?" responses and the data collected during our field seismic intensity investigation. We conducted a field investigation in Honduras between May 30 and June 6, 2009, focused on areas with local reports of damage, including the cities of La Ceiba, El Progresso, San Pedro Sula, Puerto Cortes in northern Honduras and the island of Roatan in the Caribbean Sea. The damage ascertained at these five sites shows that the severity of damage did not decrease with distance from the epicenter as predicted by standard attenuation relations. Instead, a concentration of damage was observed in El Progresso, approximately 75 km directly south from the SW end of the rupture and 160 km from the epicenter. The island of Roatan, just 30 km from the epicenter, was graded as VI on the Modified Mercalli Intensity scale while, El Progresso was graded as VIII (one unit higher than “Did you feel it?”). These intensity anomalies can be explained by two factors: (1) SW-directed rupture propagation and proximity to a localized 3.0m slip pulse (asperity) that occurred near the SW end of the fault (Hayes and Ji, 2009) that focused energy toward the city of El Progress on the mainland and; (2) local site effects, particularly the Precambrian schists and gneisses on the island of Roatan, in contrast to the soft river deposits (sand, organics, and clay) beneath the city of El Progresso. This study demonstrates the impact of seismic directivity, a fault asperity, and local site conditions on the observed damage patterns from the May 28, 2009 M 7.3 earthquake.

Stochastic output error vibration-based damage detection and assessment in structures under earthquake excitation

NASA Astrophysics Data System (ADS)

Sakellariou, J. S.; Fassois, S. D.

2006-11-01

A stochastic output error (OE) vibration-based methodology for damage detection and assessment (localization and quantification) in structures under earthquake excitation is introduced. The methodology is intended for assessing the state of a structure following potential damage occurrence by exploiting vibration signal measurements produced by low-level earthquake excitations. It is based upon (a) stochastic OE model identification, (b) statistical hypothesis testing procedures for damage detection, and (c) a geometric method (GM) for damage assessment. The methodology's advantages include the effective use of the non-stationary and limited duration earthquake excitation, the handling of stochastic uncertainties, the tackling of the damage localization and quantification subproblems, the use of "small" size, simple and partial (in both the spatial and frequency bandwidth senses) identified OE-type models, and the use of a minimal number of measured vibration signals. Its feasibility and effectiveness are assessed via Monte Carlo experiments employing a simple simulation model of a 6 storey building. It is demonstrated that damage levels of 5% and 20% reduction in a storey's stiffness characteristics may be properly detected and assessed using noise-corrupted vibration signals.

Continuous permeability measurements record healing inside the Wenchuan earthquake fault zone.

PubMed

Xue, Lian; Li, Hai-Bing; Brodsky, Emily E; Xu, Zhi-Qing; Kano, Yasuyuki; Wang, Huan; Mori, James J; Si, Jia-Liang; Pei, Jun-Ling; Zhang, Wei; Yang, Guang; Sun, Zhi-Ming; Huang, Yao

2013-06-28

Permeability controls fluid flow in fault zones and is a proxy for rock damage after an earthquake. We used the tidal response of water level in a deep borehole to track permeability for 18 months in the damage zone of the causative fault of the 2008 moment magnitude 7.9 Wenchuan earthquake. The unusually high measured hydraulic diffusivity of 2.4 × 10(-2) square meters per second implies a major role for water circulation in the fault zone. For most of the observation period, the permeability decreased rapidly as the fault healed. The trend was interrupted by abrupt permeability increases attributable to shaking from remote earthquakes. These direct measurements of the fault zone reveal a process of punctuated recovery as healing and damage interact in the aftermath of a major earthquake.

Validation of the Earthquake Archaeological Effects methodology by studying the San Clemente cemetery damages generated during the Lorca earthquake of 2011

NASA Astrophysics Data System (ADS)

Martín-González, Fidel; Martín-Velazquez, Silvia; Rodrigez-Pascua, Miguel Angel; Pérez-López, Raul; Silva, Pablo

2014-05-01

The intensity scales determined the damage caused by an earthquake. However, a new methodology takes into account not only the damage but the type of damage "Earthquake Archaeological Effects", EAE's, and its orientation (e.g. displaced masonry blocks, conjugated fractures, fallen and oriented columns, impact marks, dipping broken corners, etc.) (Rodriguez-Pascua et al., 2011; Giner-Robles et al., 2012). Its main contribution is that it focuses not only on the amount of damage but also in its orientation, giving information about the ground motion during the earthquake. Therefore, this orientations and instrumental data can be correlated with historical earthquakes. In 2011 an earthquake of magnitude Mw 5.2 took place in Lorca (SE Spain) (9 casualties and 460 million Euros in reparations). The study of the EAE's was carried out through the whole city (Giner-Robles et al., 2012). The present study aimed to a.- validate the EAE's methodology using it only in a small place, specifically the cemetery of San Clemente in Lorca, and b.- constraining the range of orientation for each EAE's. This cemetery has been selected because these damage orientation data can be correlated with instrumental information available, and also because this place has: a.- wide variety of architectural styles (neogothic, neobaroque, neoarabian), b.- its Cultural Interest (BIC), and c.- different building materials (brick, limestone, marble). The procedure involved two main phases: a.- inventory and identification of damage (EAE's) by pictures, and b.- analysis of the damage orientations. The orientation was calculated for each EAE's and plotted in maps. Results are NW-SE damage orientation. This orientation is consistent with that recorded in the accelerometer of Lorca (N160°E) and with that obtained from the analysis of EAE's for the whole town of Lorca (N130°E) (Giner-Robles et al., 2012). Due to the existence of an accelerometer, we know the orientation of the peak ground acceleration and we have been able to constrain the ranges of orientation for each EAE's. The orientation of the damage is not usually recorded after an earthquake; however, it can provide information on seismic source in historical earthquakes. References Giner-Robles, J. L., Perez-Lopez, R., Silva Barroso, P., Rodriguez-Pascua, M. A., Martin-Gonzalez, F. and Cabanas, L. 2012. Analisis estructural de danos orientados en el terremoto de Lorca del 11 de mayo de 2011. Aplicaciones en arqueosismologia. Boletín Geológico y Minero, 123 (4): 503-513 Rodriguez-Pascua, M.A., Perez-Lopez, R., Silva, P.G., Giner- Robles, J.L., Garduno-Monroy, V.H. and Reicherter, K. 2011. A Comprehensive Classification of Earthquake Archaeological Effects (EAE) for Archaeoseismology. Quaternary International, 242, 20-30.

24 CFR 203.378 - Property condition.

Code of Federal Regulations, 2010 CFR

2010-04-01

... the Commissioner, the property shall be undamaged by fire, earthquake, flood, or tornado, except as... mortgagee shall be responsible for: (1) Damage by fire, flood, earthquake, hurricane, or tornado; (2) Damage...

24 CFR 203.378 - Property condition.

Code of Federal Regulations, 2011 CFR

2011-04-01

... the Commissioner, the property shall be undamaged by fire, earthquake, flood, or tornado, except as... mortgagee shall be responsible for: (1) Damage by fire, flood, earthquake, hurricane, or tornado; (2) Damage...

24 CFR 203.378 - Property condition.

Code of Federal Regulations, 2013 CFR

2013-04-01

... the Commissioner, the property shall be undamaged by fire, earthquake, flood, or tornado, except as... mortgagee shall be responsible for: (1) Damage by fire, flood, earthquake, hurricane, or tornado; (2) Damage...

24 CFR 203.378 - Property condition.

Code of Federal Regulations, 2014 CFR

2014-04-01

... the Commissioner, the property shall be undamaged by fire, earthquake, flood, or tornado, except as... mortgagee shall be responsible for: (1) Damage by fire, flood, earthquake, hurricane, or tornado; (2) Damage...

24 CFR 203.378 - Property condition.

Code of Federal Regulations, 2012 CFR

2012-04-01

... the Commissioner, the property shall be undamaged by fire, earthquake, flood, or tornado, except as... mortgagee shall be responsible for: (1) Damage by fire, flood, earthquake, hurricane, or tornado; (2) Damage...

Are you prepared for the next big earthquake in Alaska?

USGS Publications Warehouse

2006-01-01

Scientists have long recognized that Alaska has more earthquakes than any other region of the United States and is, in fact, one of the most seismically active areas of the world. The second-largest earthquake ever recorded shook the heart of southern Alaska on March 27th, 1964. The largest strike-slip slip earthquake in North America in almost 150 years occurred on the Denali Fault in central Alaska on November 3rd, 2002. “Great” earthquakes (larger than magnitude 8) have rocked the state on an average of once every 13 years since 1900. It is only a matter of time before another major earthquake will impact a large number of Alaskans.Alaska has changed significantly since the damaging 1964 earthquake, and the population has more than doubled. Many new buildings are designed to withstand intense shaking, some older buildings have been reinforced, and development has been discouraged in some particularly hazardous areas. Despite these precautions, future earthquakes may still cause damage to buildings, displace items within buildings, and disrupt the basic utilities that we take for granted. We must take every reasonable action to prepare for damaging earthquakes in order to lower these risks.

Sizing up earthquake damage: Differing points of view

USGS Publications Warehouse

Hough, S.; Bolen, A.

2007-01-01

When a catastrophic event strikes an urban area, many different professionals hit the ground running. Emergency responders respond, reporters report, and scientists and engineers collect and analyze data. Journalists and scientists may share interest in these events, but they have very different missions. To a journalist, earthquake damage is news. To a scientist or engineer, earthquake damage represents a valuable source of data that can help us understand how strongly the ground shook as well as how particular structures responded to the shaking.

A Cloud Computing Approach to Personal Risk Management: The Open Hazards Group

NASA Astrophysics Data System (ADS)

Graves, W. R.; Holliday, J. R.; Rundle, J. B.

2010-12-01

According to the California Earthquake Authority, only about 12% of current California residences are covered by any form of earthquake insurance, down from about 30% in 1996 following the 1994, M6.7 Northridge earthquake. Part of the reason for this decreasing rate of insurance uptake is the high deductible, either 10% or 15% of the value of the structure, and the relatively high cost of the premiums, as much as thousands of dollars per year. The earthquake insurance industry is composed of the CEA, a public-private partnership; modeling companies that produce damage and loss models similar to the FEMA HAZUS model; and financial companies such as the insurance, reinsurance, and investment banking companies in New York, London, the Cayman Islands, Zurich, Dubai, Singapore, and elsewhere. In setting earthquake insurance rates, financial companies rely on models like HAZUS, that calculate on risk and exposure. In California, the process begins with an official earthquake forecast by the Working Group on California Earthquake Probabilities. Modeling companies use these 30 year earthquake probabilities as inputs to their attenuation and damage models to estimate the possible damage factors from scenario earthquakes. Economic loss is then estimated from processes such as structural failure, lost economic activity, demand surge, and fire following the earthquake. Once the potential losses are known, rates can be set so that a target ruin probability of less than 1% or so can be assured. Open Hazards Group was founded with the idea that the global public might be interested in a personal estimate of earthquake risk, computed using data supplied by the public, with models running in a cloud computing environment. These models process data from the ANSS catalog, updated at least daily, to produce rupture forecasts that are backtested with standard Reliability/Attributes and Receiver Operating Characteristic tests, among others. Models for attenuation and structural damage are then used in a computationally efficient workflow to produce real-time estimates of damage and loss for individual structures. All models are based on techniques that either have been published in the literature or will soon be published. Using these results, members of the public can gain an appreciation of their risk of exposure to damage from destructive earthquakes, information that has heretofore only been available to a few members of the financial and insurance industries.

Historical perspective on seismic hazard to Hispaniola and the northeast Caribbean region

USGS Publications Warehouse

ten Brink, Uri S.; Bakun, W.H.; Flores, C.H.

2011-01-01

We evaluate the long-term seismic activity of the North-American/Caribbean plate boundary from 500 years of historical earthquake damage reports. The 2010 Haiti earthquakes and other earthquakes were used to derive regional attenuation relationships between earthquake intensity, magnitude, and distance from the reported damage to the epicenter, for Hispaniola and for Puerto Rico and the Virgin Islands. The attenuation relationship for Hispaniola earthquakes and northern Lesser Antilles earthquakes is similar to that for California earthquakes, indicating a relatively rapid attenuation of damage intensity with distance. Intensities in Puerto Rico and the Virgin Islands decrease less rapidly with distance. We use the intensity-magnitude relationships to systematically search for the location and intensity magnitude MI which best fit all the reported damage for historical earthquakes. Many events occurred in the 20th-century along the plate-boundary segment from central Hispaniola to the NW tip of Puerto Rico, but earlier events from this segment were not identified. The remaining plate boundary to the east to Guadeloupe is probably not associated with M > 8 historical subduction-zone earthquakes. The May 2, 1787 earthquake, previously assigned an M 8–8.25, is probably only MI 6.9 and could be located north, west or SW of Puerto Rico. An MI 6.9 earthquake on July 11, 1785 was probably located north or east of the Virgin Islands. We located MI I 7.7) and May 7, 1842 (MI 7.6) earthquakes ruptured the Septentrional Fault in northern Hispaniola. If so, the recurrence interval on the central Septentrional Fault is ~300 years, and only 170 years has elapsed since the last event. The recurrence interval of large earthquakes along the Hispaniola subduction segment is likely longer than the historical record. Intra-arc M ≥ 7.0 earthquakes may occur every 75–100 years in the 410-km-long segment between the Virgin Islands and Guadeloupe.

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.

Comparison of the sand liquefaction estimated based on codes and practical earthquake damage phenomena

NASA Astrophysics Data System (ADS)

Fang, Yi; Huang, Yahong

2017-12-01

Conducting sand liquefaction estimated based on codes is the important content of the geotechnical design. However, the result, sometimes, fails to conform to the practical earthquake damages. Based on the damage of Tangshan earthquake and engineering geological conditions, three typical sites are chosen. Moreover, the sand liquefaction probability was evaluated on the three sites by using the method in the Code for Seismic Design of Buildings and the results were compared with the sand liquefaction phenomenon in the earthquake. The result shows that the difference between sand liquefaction estimated based on codes and the practical earthquake damage is mainly attributed to the following two aspects: The primary reasons include disparity between seismic fortification intensity and practical seismic oscillation, changes of groundwater level, thickness of overlying non-liquefied soil layer, local site effect and personal error. Meanwhile, although the judgment methods in the codes exhibit certain universality, they are another reason causing the above difference due to the limitation of basic data and the qualitative anomaly of the judgment formulas.

Correlations between ground motion and building damage. Engineering intensity scale applied to the San Fernando earthquake of February 1971

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

Hafen, D.; Kintzer, F.C.

1977-11-01

The correlation between ground motion and building damage was investigated for the San Fernando earthquake of 1971. A series of iso-intensity maps was compiled to summarize the ground motion in terms of the Blume Engineering Intensity Scale (EIS). This involved the analysis of ground motion records from 62 stations in the Los Angeles area. Damage information for low-rise buildings was obtained in the form of records of loans granted by the Small Business Administration to repair earthquake damage. High-rise damage evaluations were based on direct inquiry and building inspection. Damage factors (ratio of damage repair cost to building value) weremore » calculated and summarized on contour maps. A statistical study was then undertaken to determine relationships between ground motion and damage factor. Several parameters for ground motion were considered and evaluated by means of correlation coefficients.« less

Geographical Information Analysis of Tsunami Flooded Area by the Great East Japan Earthquake Using Mobile Mapping System

NASA Astrophysics Data System (ADS)

Koarai, M.; Okatani, T.; Nakano, T.; Nakamura, T.; Hasegawa, M.

2012-07-01

The great earthquake occurred in Tohoku District, Japan on 11th March, 2011. This earthquake is named "the 2011 off the Pacific coast of Tohoku Earthquake", and the damage by this earthquake is named "the Great East Japan Earthquake". About twenty thousand people were killed or lost by the tsunami of this earthquake, and large area was flooded and a large number of buildings were destroyed by the tsunami. The Geospatial Information Authority of Japan (GSI) has provided the data of tsunami flooded area interpreted from aerial photos taken just after the great earthquake. This is fundamental data of tsunami damage and very useful for consideration of reconstruction planning of tsunami damaged area. The authors analyzed the relationship among land use, landform classification, DEMs data flooded depth of the tsunami flooded area by the Great East Japan Earthquake in the Sendai Plain using GIS. Land use data is 100 meter grid data of National Land Information Data by the Ministry of Land, Infrastructure, Transportation and Tourism (MLIT). Landform classification data is vector data of Land Condition Map produced by GSI. DEMs data are 5 meters grid data measured with LiDAR by GSI after earthquake. Especially, the authors noticed the relationship between tsunami hazard damage and flooded depth. The authors divided tsunami damage into three categories by interpreting aerial photos; first is the completely destroyed area where almost wooden buildings were lost, second is the heavily damaged area where a large number of houses were destroyed by the tsunami, and third is the flooded only area where houses were less destroyed. The flooded depth was measured by photogrammetric method using digital image taken by Mobile Mapping System (MMS). The result of these geographic analyses show the distribution of tsunami damage level is as follows: 1) The completely destroyed area was located within 1km area from the coastline, flooded depth of this area is over 4m, and no relationship between damaged area and landform classification. 2) The heavily damaged area was observed up to 3 or 4km from the coastline. Flooded depth of this area is over 1.5m, and there is a good relationship between damaged area and height of DEMs. 3) The flood only area was observed up to 4 or 5km from the coastline. Flooded depth of this area was less than 1.5m, and there is a good relationship between damaged area and landform. For instance, a certain area in valley plain or flooded plain was not affected by the tsunami, even though an area with almost the same height in coastal plain or delta was flooded. These results mean that it is important for tsunami disaster management to consider not only DEMs but also landform classification.

Geographic variation of clinically diagnosed mood and anxiety disorders in Christchurch after the 2010/11 earthquakes.

PubMed

Hogg, Daniel; Kingham, Simon; Wilson, Thomas M; Griffin, Edward; Ardagh, Michael

2014-11-01

The 22nd February 2011 Christchurch earthquake killed 185 people, injured over 8000, damaged over 100,000 buildings and on-going aftershocks maintained high anxiety levels. This paper examines the dose of exposure effect of earthquake damage assessments, earthquake intensity measures, liquefaction and lateral spreading on mood and anxiety disorders in Christchurch after this event. We hypothesise that such disorders are more likely to develop in people who have experienced greater exposure to these impacts within their neighborhood than others who have been less exposed, but also live in the city. For this purpose, almost all clinically diagnosed incident and relapsed cases in Christchurch in a 12 months period after the 2011 earthquake were analysed. Spatio-temporal cluster analysis shows that people living in the widely affected central and eastern parts after the 2010/11 earthquakes have a 23% higher risk of developing a mood or anxiety disorder than people living in other parts of the city. Generally, mood and anxiety-related disorders increase with closer proximity to damage from liquefaction and moderate to major lateral spreading, as well as areas that are more likely to suffer from damage in future earthquakes. Copyright © 2014 Elsevier Ltd. All rights reserved.

The Christchurch earthquake stroke incidence study.

PubMed

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

2014-03-01

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

Damage from the El Mayor-Cucapah earthquake, April 2010: Why society cannot afford to ignore seismic risks to agricultural regions

NASA Astrophysics Data System (ADS)

Stenner, H. D.; Mathieson, E. L.; Okubo, S.; Anderson, R.; Rodriguez C., M. A.

2010-12-01

The M7.2 El Mayor-Cucapah earthquake of April 4, 2010 in Mexico’s Baja California caused extensive damage to the agricultural area of Mexicali Valley. The damage included wide-spread liquefaction and lateral spreading which destroyed or damaged irrigation canals. Without water, wheat, alfalfa, and other crops were lost. Fields were cut by fissures and partially buried by massive sand blows. Regional tilting from the earthquake was a serious issue for the gravity-controlled irrigation system. Ruptured canals and groundwater from sand blows flooded fields, roads, and towns. Flooding further damaged crops and brought contamination with it. Fissures and scarps through farm communities cracked buildings; ruptured water, sewer, and other pipelines; and made roads temporarily difficult to pass. Economically, farmers, seasonal farm workers, and agricultural suppliers were affected; reducing their ability to consume the goods and services of businesses unrelated to agriculture. Similar damage was observed in earlier earthquakes over the past 100 years. Society quickly forgets how the earth responds to strong shaking. We hope to provide a vivid portrait of this agricultural disaster so that other farming communities prone to strong seismic shaking may visualize what can happen from their own inevitable future earthquake. Fissure and sand blows southeast of Cucapah, Baja California, April 16, 2010. Heavily damaged irrigation canal northwest of Zacamoto, Baja California, April 15, 2010.

Damage during the 6-24 February 2017 Ayvacık (Çanakkale) earthquake swarm

NASA Astrophysics Data System (ADS)

Livaoğlu, Ramazan; Ömer Timurağaoğlu, Mehmet; Serhatoğlu, Cavit; Sami Döven, Mahmud

2018-03-01

On 6 February 2017 an earthquake swarm began at the western end of Turkey. This was the first recorded swarm in the Çanakkale region since continuous seismic monitoring began in 1970. The number of earthquakes located increased during the following 10 days. This paper describes the output of a survey carried out in the earthquake-prone towns in the area of Ayvacık, Çanakkale, Turkey, in February 2017 after the earthquakes. Observations of traditional buildings were made on site at the rural area of Ayvacık. A description of the main structural features and their effects on the most frequently viewed damage modes were made according to in-plane, out-of-plane behavior of the wall regarding construction practice, connection type, etc. It was found that there were no convenient connections like cavity ties or sufficient mortar strength resulting in decreased and/or lack of lateral load bearing capacity of the wall. Furthermore, distribution maps of damaged/undamaged buildings according to villages, damage ratios, structures and damage levels are generated. Distribution maps showed that damage ratio of structures is higher in villages close to epicenter and decrease away from epicenter except Gülpınar, where past experiences and development level affect the construction quality.

Earthquakes in Mississippi and vicinity 1811-2010

USGS Publications Warehouse

Dart, Richard L.; Bograd, Michael B.E.

2011-01-01

This map summarizes two centuries of earthquake activity in Mississippi. Work on the Mississippi map was done in collaboration with the Mississippi Department of Environmental Quality, Office of Geology. The earthquake data plotted on the map are from several sources: the Mississippi Department of Environmental Quality, the Center for Earthquake Research and Information, the National Center for Earthquake Engineering Research, and the Arkansas Geological Survey. In addition to earthquake locations, other materials include seismic hazard and isoseismal maps and related text. Earthquakes are a legitimate concern in Mississippi and parts of adjacent States. Mississippi has undergone a number of felt earthquakes since 1811. At least two of these events caused property damage: a magnitude 4.7 earthquake in 1931, and a magnitude 4.3 earthquake in 1967. The map shows all historical and instrumentally located earthquakes in Mississippi and vicinity between 1811 and 2010. The largest historic earthquake in the vicinity of the State was an intensity XI event, on December 16, 1811; the first earthquake in the New Madrid sequence. This violent event and the earthquakes that followed caused considerable damage to the then sparsely settled region.

Distribution of intensity for the Westmorland, California, earthquake of April 26, 1981

USGS Publications Warehouse

Barnhard, L.M.; Thenhaus, P.C.; Algermissen, Sylvester Theodore

1982-01-01

The maximum Modified Mercalli intensity of the April 26, 1981 earthquake located 5 km northwest of Westmorland, California is VII. Twelve buildings in Westmorland were severely damaged with an additional 30 sustaining minor damage. Two brick parapets fell in Calipatria, 14 km northeast of Westmorland and 10 km from the earthquake epicenter. Significant damage in rural areas was restricted to unreinforced, concrete-lined irrigation canals. Liquefaction effects and ground slumping were widespread in rural areas and were the primary causes of road cracking. Preliminary local government estimates of property loss range from one to three million dollars (Imperial Valley Press, 1981). The earthquake was felt over an area of approximately 160,000 km2; about the same felt area of the October 15, 1979 (Reagor and others, 1980), and May 18, 1940 (Ulrich, 1941) Imperial Valley earthquakes.

Taiwan Earthquake Damage Index Sin Mei Nga* and Masataka Andob a* Department of Geology, Chinese Culture University, No. 55, Hwa-Kang Road, Yang-Ming-Shan, Taipei 11114, Taiwan b Institute of Earth Sciences, Academia Sinica, 128, Sec2, Academia Road, Nangang, Taipei 11529, Taiwan * Corresponding author. Tel.: +886 (02) 28 61 05 11 ext.26133 fax: +886 (02) 28 61 49 59 E-mail: wsw2@ulive.pccu.edu.tw or sin_mei_josephine_ng@hotmail.com

NASA Astrophysics Data System (ADS)

Ng, S.

2012-12-01

Taking advantage of a previous study and twelve-year, free-field strong motion data in Taiwan, a preliminary, five-level earthquake damage index is newly proposed: I-No (no damage), II-Very Light, III-Light, IV-Moderate, and V-Heavy. For index I, PGA and PGV are, respectively, <62.5 gal and <11 cm/s. Likewise, for index II, PGA is ≧62.5 and ≦187.5 gal; but, PGV is ≧11 and ≦35 cm/s. Similarly, PGA is ≧187.5 and ≦325 gal; but, PGV is ≧35 and ≦55 cm/s for index III. The corresponding PGA and PGV, for index IV, are ≧325 and ≦450 gal and ≧55 and ≦75 cm/s. Finally, for index V, PGA and PGV are respectively >450 gal and >75 cm/s. Ten damaging seismic events in the past twelve years are redefined using this new earthquake damage index, with the devastating Chi-Chi earthquake and one non-damaging event as reference earthquakes. This newly proposed index depicts seismic hazard of these earthquakes with higher accuracy when compared to the existing intensity scale in Taiwan region. For further analysis, Japan earthquakes are also plotted as references.

Seismic vulnerability: theory and application to Algerian buildings

NASA Astrophysics Data System (ADS)

Mebarki, Ahmed; Boukri, Mehdi; Laribi, Abderrahmane; Farsi, Mohammed; Belazougui, Mohamed; Kharchi, Fattoum

2014-04-01

When dealing with structural damages, under the effect of natural hazards such as earthquakes, it is still a scientific challenge to predict the potential damages, before occurrence of a given hazard, as well as to evaluate the damages once the earthquake has occurred. In the present study, two distinct methods addressing these topics are developed. Thousands (˜54,000) of existing buildings damaged during the Boumerdes earthquake that occurred in Algeria (Mw = 6.8, May 21, 2003) are considered in order to study their accuracy and sensitivity. Once an earthquake has occurred, quick evaluations of the damages are required in order to distinguish which structures should be demolished or evacuated immediately from those which can be kept in service without evacuation of its inhabitants. For this purpose, visual inspections are performed by trained and qualified engineers. For the case of Algeria, an evaluation form has been developed and is still in use since the early 80s: Five categories of damages are considered (no damage or very slight, slight, moderate, major, and very severe/collapse). This paper develops a theoretical methodology that processes the observed damages caused to the structural and nonstructural components (foundations, roofs, slabs, walls, beams, columns, fillings, partition walls, stairways, balconies, etc.), in order to help the evaluator to derive the global damage evaluation. This theoretical methodology transforms the damage category into a corresponding "residual" risk of failure ranging from zero (no damage) to one (complete damage). The global failure risk, in fact its corresponding damage category, is then derived according to given combinations of probabilistic events in order to express the influence of any component on the global damage and behavior. The method is calibrated on a set of ˜54,000 buildings inspected after Boumerdes earthquake. Almost 80 % of accordance (same damage category) is obtained, when comparing the theoretical results to the observed damages. For pre-earthquake analysis, the methodology widely used around the world relies on the prior calibration of the seismic response of the structures under given expected scenarios. As the structural response is governed by the constitutive materials and structural typology as well as the seismic input and soil conditions, the damage prediction depends intimately on the accuracy of the so-called fragility curve and response spectrum established for each type of structure (RC framed structures, confined or unconfined masonry, etc.) and soil (hard rock, soft soil, etc.). In the present study, the adaptation to Algerian buildings concerns the specific soil conditions as well as the structural dynamic response. The theoretical prediction of the expected damages is helpful for the calibration of the methodology. Thousands (˜3,700) of real structures and the damages caused by the earthquake (Algeria, Boumerdes: Mw = 6.8, May 21, 2003) are considered for the a posteriori calibration and validation process. The theoretical predictions show the importance of the elastic response spectrum, the local soil conditions, and the structural typology. Although the observed and predicted categories of damage are close, it appears that the existing form used for the visual damage inspection would still require further improvements, in order to allow easy evaluation and identification of the damage level. These methods coupled to databases, and GIS tools could be helpful for the local and technical authorities during the post-earthquake evaluation process: real time information on the damage extent at urban or regional scales as well as the extent of losses and the required resources for reconstruction, evacuation, strengthening, etc.

GIS-based seismic shaking slope vulnerability map of Sicily (Central Mediterranean)

NASA Astrophysics Data System (ADS)

Nigro, Fabrizio; Arisco, Giuseppe; Perricone, Marcella; Renda, Pietro; Favara, Rocco

2010-05-01

Earthquakes often represent very dangerouses natural events in terms of human life and economic losses and their damage effects are amplified by the synchronous occurrence of seismically-induced ground-shaking failures in wide regions around the seismogenic source. In fact, the shaking associated with big earthquakes triggers extensive landsliding, sometimes at distances of more than 100 km from the epicenter. The active tectonics and the geomorphic/morphodinamic pattern of the regions affected by earthquakes contribute to the slopes instability tendency. In fact, earthquake-induced groun-motion loading determines inertial forces activation within slopes that, combined with the intrinsic pre-existing static forces, reduces the slope stability towards its failure. Basically, under zero-shear stress reversals conditions, a catastrophic failure will take place if the earthquake-induced shear displacement exceeds the critical level of undrained shear strength to a value equal to the gravitational shear stress. However, seismic stability analyses carried out for various infinite slopes by using the existing Newmark-like methods reveal that estimated permanent displacements smaller than the critical value should also be regarded as dangerous for the post-earthquake slope safety, in terms of human activities use. Earthquake-induced (often high-speed) landslides are among the most destructive phenomena related to slopes failure during earthquakes. In fact, damage from earthquake-induced landslides (and other ground-failures), sometimes exceeds the buildings/infrastructures damage directly related to ground-shaking for fault breaking. For this matter, several hearthquakes-related slope failures methods have been developed, for the evaluation of the combined hazard types represented by seismically ground-motion landslides. The methodologies of analysis of the engineering seismic risk related to the slopes instability processes is often achieved through the evaluation of the permanent displacement potentially induced by an seismic scenario. Such methodologies found on the consideration that the conditions of seismic stability and the post-seismic functionality of engineering structures are tightly related to the entity of the permanent deformations that an earthquake can induce. Regarding the existing simplified procedures among slope stability models, Newmark's model is often used to derive indications about slope instabilities due to earthquakes. In this way, we have evaluated the seismically-induced landslides hazard in Sicily (Central Mediterranean) using the Newmark-like model. In order to determine the map distribution of the seismic ground-acceleration from an earthquake scenario, the attenuation-law of Sabetta & Pugliese has been used, analyzing some seismic recordings occurred in Italy. Also, by evaluating permanent displacements, the correlation of Ambraseys & Menu has been assumed. The seismic shaking slope vulnerability map of Sicily has been carried out using GIS application, also considering max seismic ground-acceleration peak distribution (in terms of exceedance probability for fixed time), slope acclivity, cohesion/angle of internal friction of outcropping rocks, allowing the zoning of the unstable slopes under seismic forces.

Rapid Damage Mapping for the 2015 M7.8 Gorkha Earthquake using Synthetic Aperture Radar Data from COSMO-SkyMed and ALOS-2 Satellites

NASA Astrophysics Data System (ADS)

Yun, S. H.; Hudnut, K. W.; Owen, S. E.; Webb, F.; Simons, M.; Macdonald, A.; Sacco, P.; Gurrola, E. M.; Manipon, G.; Liang, C.; Fielding, E. J.; Milillo, P.; Hua, H.; Coletta, A.

2015-12-01

The April 25, 2015 M7.8 Gorkha earthquake caused more than 8,000 fatalities and widespread building damage in central Nepal. Four days after the earthquake, the Italian Space Agency's (ASI's) COSMO-SkyMed Synthetic Aperture Radar (SAR) satellite acquired data over Kathmandu area. Nine days after the earthquake, the Japan Aerospace Exploration Agency's (JAXA's) ALOS-2 SAR satellite covered larger area. Using these radar observations, we rapidly produced damage proxy maps derived from temporal changes in Interferometric SAR (InSAR) coherence. These maps were qualitatively validated through comparison with independent damage analyses by National Geospatial-Intelligence Agency (NGA) and the UNITAR's (United Nations Institute for Training and Research's) Operational Satellite Applications Programme (UNOSAT), and based on our own visual inspection of DigitalGlobe's WorldView optical pre- vs. post-event imagery. Our maps were quickly released to responding agencies and the public, and used for damage assessment, determining inspection/imaging priorities, and reconnaissance fieldwork.

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.

Assessing the location and magnitude of the 20 October 1870 Charlevoix, Quebec, earthquake

USGS Publications Warehouse

Ebel, John E.; Dupuy, Megan; Bakun, William H.

2013-01-01

The Charlevoix, Quebec, earthquake of 20 October 1870 caused damage to several towns in Quebec and was felt throughout much of southeastern Canada and along the U.S. Atlantic seaboard from Maine to Maryland. Site‐specific damage and felt reports from Canadian and U.S. cities and towns were used in analyses of the location and magnitude of the earthquake. The macroseismic center of the earthquake was very close to Baie‐St‐Paul, where the greatest damage was reported, and the intensity magnitude MI was found to be 5.8, with a 95% probability range of 5.5–6.0. After corrections for epicentral‐distance differences are applied, the modified Mercalli intensity (MMI) data for the 1870 earthquake and for the moment magnitude M 6.2 Charlevoix earthquake of 1925 at common sites show that on average, the MMI readings are about 0.8 intensity units smaller for the 1870 earthquake than for the 1925 earthquake, suggesting that the 1870 earthquake was MI 5.7. A similar comparison of the MMI data for the 1870 earthquake with the corresponding data for the M 5.9 1988 Saguenay event suggests that the 1870 earthquake was MI 6.0. These analyses all suggest that the magnitude of the 1870 Charlevoix earthquake is between MI 5.5 and MI 6.0, with a best estimate of MI 5.8.

The Road to Total Earthquake Safety

NASA Astrophysics Data System (ADS)

Frohlich, Cliff

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

A Tsunami Model for Chile for (Re) Insurance Purposes

NASA Astrophysics Data System (ADS)

Arango, Cristina; Rara, Vaclav; Puncochar, Petr; Trendafiloski, Goran; Ewing, Chris; Podlaha, Adam; Vatvani, Deepak; van Ormondt, Maarten; Chandler, Adrian

2014-05-01

Catastrophe models help (re)insurers to understand the financial implications of catastrophic events such as earthquakes and tsunamis. In earthquake-prone regions such as Chile,(re)insurers need more sophisticated tools to quantify the risks facing their businesses, including models with the ability to estimate secondary losses. The 2010 (M8.8) Maule (Chile) earthquake highlighted the need for quantifying losses from secondary perils such as tsunamis, which can contribute to the overall event losses but are not often modelled. This paper presents some key modelling aspects of a new earthquake catastrophe model for Chile developed by Impact Forecasting in collaboration with Aon Benfield Research partners, focusing on the tsunami component. The model has the capability to model tsunami as a secondary peril - losses due to earthquake (ground-shaking) and induced tsunamis along the Chilean coast are quantified in a probabilistic manner, and also for historical scenarios. The model is implemented in the IF catastrophe modelling platform, ELEMENTS. The probabilistic modelling of earthquake-induced tsunamis uses a stochastic event set that is consistent with the seismic (ground shaking) hazard developed for Chile, representing simulations of earthquake occurrence patterns for the region. Criteria for selecting tsunamigenic events (from the stochastic event set) are proposed which take into consideration earthquake location, depth and the resulting seabed vertical displacement and tsunami inundation depths at the coast. The source modelling software RuptGen by Babeyko (2007) was used to calculate static seabed vertical displacement resulting from earthquake slip. More than 3,600 events were selected for tsunami simulations. Deep and shallow water wave propagation is modelled using the Delft3D modelling suite, which is a state-of-the-art software developed by Deltares. The Delft3D-FLOW module is used in 2-dimensional hydrodynamic simulation settings with non-steady flow. Earthquake-induced static seabed vertical displacement is used as an input boundary condition to the model. The model is hierarchically set up with three nested domain levels; with 250 domains in total covering the entire Chilean coast. Spatial grid-cell resolution is equal to the native SRTM resolution of approximately 90m. In addition to the stochastic events, the 1960 (M9.5) Valdivia and 2010 (M8.8) Maule earthquakes are modelled. The modelled tsunami inundation map for the 2010 Maule event is validated through comparison with real observations. The vulnerability component consists of an extensive damage curves database, including curves for buildings, contents and business interruption for 21 occupancies, 24 structural types and two secondary modifies such as building height and period of construction. The building damage curves are developed by use of load-based method in which the building's capacity to resist tsunami loads is treated as equivalent to the design earthquake load capacity. The contents damage and business interruption curves are developed by use of deductive approach i.e. HAZUS flood vulnerability and business function restoration models are adapted for detailed occupancies and then assigned to the dominant structural types in Chile. The vulnerability component is validated through model overall back testing by use of observed aggregated earthquake and tsunami losses for client portfolios for 2010 Maule earthquake.

Introduction to the focus section on the 2015 Gorkha, Nepal, earthquake

USGS Publications Warehouse

Hough, Susan E.

2015-01-01

It has long been recognized that Nepal faces high earthquake hazard, with the most recent large (Mw>7.5) events in 1833 and 1934. When the 25 April 2015Mw 7.8 Gorkha earthquake struck, it appeared initially to be a realization of worst fears. In spite of its large magnitude and proximity to the densely populated Kathmandu valley, however, the level of damage was lower than anticipated, with most vernacular structures within the valley experiencing little or no structural damage. Outside the valley, catastrophic damage did occur in some villages, associated with the high vulnerability of stone masonry construction and, in many cases, landsliding. The unexpected observations from this expected earthquake provide an urgent impetus to understand the event itself and to better characterize hazard from future large Himalayan earthquakes. Toward this end, articles in this special focus section present and describe available data sets and initial results that better illuminate and interpret the earthquake and its effects.

Hotspots, Lifelines, and the Safrr Haywired Earthquake Sequence

NASA Astrophysics Data System (ADS)

Ratliff, J. L.; Porter, K.

2014-12-01

Though California has experienced many large earthquakes (San Francisco, 1906; Loma Prieta, 1989; Northridge, 1994), the San Francisco Bay Area has not had a damaging earthquake for 25 years. Earthquake risk and surging reliance on smartphones and the Internet to handle everyday tasks raise the question: is an increasingly technology-reliant Bay Area prepared for potential infrastructure impacts caused by a major earthquake? How will a major earthquake on the Hayward Fault affect lifelines (roads, power, water, communication, etc.)? The U.S. Geological Survey Science Application for Risk Reduction (SAFRR) program's Haywired disaster scenario, a hypothetical two-year earthquake sequence triggered by a M7.05 mainshock on the Hayward Fault, addresses these and other questions. We explore four geographic aspects of lifeline damage from earthquakes: (1) geographic lifeline concentrations, (2) areas where lifelines pass through high shaking or potential ground-failure zones, (3) areas with diminished lifeline service demand due to severe building damage, and (4) areas with increased lifeline service demand due to displaced residents and businesses. Potential mainshock lifeline vulnerability and spatial demand changes will be discerned by superimposing earthquake shaking, liquefaction probability, and landslide probability damage thresholds with lifeline concentrations and with large-capacity shelters. Intersecting high hazard levels and lifeline clusters represent potential lifeline susceptibility hotspots. We will also analyze possible temporal vulnerability and demand changes using an aftershock shaking threshold. The results of this analysis will inform regional lifeline resilience initiatives and response and recovery planning, as well as reveal potential redundancies and weaknesses for Bay Area lifelines. Identified spatial and temporal hotspots can provide stakeholders with a reference for possible systemic vulnerability resulting from an earthquake sequence.

Napa Earthquake impact on water systems

NASA Astrophysics Data System (ADS)

Wang, J.

2014-12-01

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

A new methodology for earthquake damage assessment (MEDEA) and its application following the Molise Italy earthquake of 31.10.02

NASA Astrophysics Data System (ADS)

Zuccaro, G.; Papa, F.; Spence, R.

2003-04-01

MEDEA is a multi-media tool designed to support earthquake damage assessment teams in Italy, by providing a means to train the technicians involved. In MEDEA, a range of alternative mechanisms of damage are defined and described, and the symptoms of each mechanism which can be recognised by the assessor are identified and linked to the related causative mechanisms. By using MEDEA, the assessor is guided by the experience of experts in the identification of the damage states and also of the separate mechanisms involved. This leads to a better safety assessment, a more homogeneous evaluation of damage across the affected area, and a great enhancement in the value of the damage statistics obtained in the assessment. The method is applied to both masonry and reinforced concrete buildings of the forms widespread in Italy and neighbouring countries. The paper will describe MEDEA and the context for which it was designed; and will present an example of its use in the M5.1 Molise earthquake of 31.10.02 in which 27 people died and which caused damage to hundreds of buildings.

Dynamic permeability in fault damage zones induced by repeated coseismic fracturing events

NASA Astrophysics Data System (ADS)

Aben, F. M.; Doan, M. L.; Mitchell, T. M.

2017-12-01

Off-fault fracture damage in upper crustal fault zones change the fault zone properties and affect various co- and interseismic processes. One of these properties is the permeability of the fault damage zone rocks, which is generally higher than the surrounding host rock. This allows large-scale fluid flow through the fault zone that affects fault healing and promotes mineral transformation processes. Moreover, it might play an important role in thermal fluid pressurization during an earthquake rupture. The damage zone permeability is dynamic due to coseismic damaging. It is crucial for earthquake mechanics and for longer-term processes to understand how the dynamic permeability structure of a fault looks like and how it evolves with repeated earthquakes. To better detail coseismically induced permeability, we have performed uniaxial split Hopkinson pressure bar experiments on quartz-monzonite rock samples. Two sample sets were created and analyzed: single-loaded samples subjected to varying loading intensities - with damage varying from apparently intact to pulverized - and samples loaded at a constant intensity but with a varying number of repeated loadings. The first set resembles a dynamic permeability structure created by a single large earthquake. The second set resembles a permeability structure created by several earthquakes. After, the permeability and acoustic velocities were measured as a function of confining pressure. The permeability in both datasets shows a large and non-linear increase over several orders of magnitude (from 10-20 up to 10-14 m2) with an increasing amount of fracture damage. This, combined with microstructural analyses of the varying degrees of damage, suggests a percolation threshold. The percolation threshold does not coincide with the pulverization threshold. With increasing confining pressure, the permeability might drop up to two orders of magnitude, which supports the possibility of large coseismic fluid pulses over relatively large distances along a fault. Also, a relatively small threshold could potentially increase permeability in a large volume of rock, given that previous earthquakes already damaged these rocks.

How citizen seismology is transforming rapid public earthquake information: the example of LastQuake smartphone application and Twitter QuakeBot

NASA Astrophysics Data System (ADS)

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

2014-12-01

Smartphone applications have swiftly become one of the most popular tools for rapid reception of earthquake information for the public. Wherever someone's own location is, they can be automatically informed when an earthquake has struck just by setting a magnitude threshold and an area of interest. No need to browse the internet: the information reaches you automatically and instantaneously! One question remains: are the provided earthquake notifications always relevant for the public? A while after damaging earthquakes many eyewitnesses scrap the application they installed just after the mainshock. Why? Because either the magnitude threshold is set too high and many felt earthquakes are missed, or it is set too low and the majority of the notifications are related to unfelt earthquakes thereby only increasing anxiety among the population at each new update. Felt and damaging earthquakes are the ones of societal importance even when of small magnitude. LastQuake app and Twitter feed (QuakeBot) focuses on these earthquakes that matter for the public by collating different information threads covering tsunamigenic, damaging and felt earthquakes. Non-seismic detections and macroseismic questionnaires collected online are combined to identify felt earthquakes regardless their magnitude. Non seismic detections include Twitter earthquake detections, developed by the USGS, where the number of tweets containing the keyword "earthquake" is monitored in real time and flashsourcing, developed by the EMSC, which detect traffic surges on its rapid earthquake information website caused by the natural convergence of eyewitnesses who rush to the Internet to investigate the cause of the shaking that they have just felt. We will present the identification process of the felt earthquakes, the smartphone application and the 27 automatically generated tweets and how, by providing better public services, we collect more data from citizens.

Effect of Different Groundwater Levels on Seismic Dynamic Response and Failure Mode of Sandy Slope

PubMed Central

Huang, Shuai; Lv, Yuejun; Peng, Yanju; Zhang, Lifang; Xiu, Liwei

2015-01-01

Heavy seismic damage tends to occur in slopes when groundwater is present. The main objectives of this paper are to determine the dynamic response and failure mode of sandy slope subjected simultaneously to seismic forces and variable groundwater conditions. This paper applies the finite element method, which is a fast and efficient design tool in modern engineering analysis, to evaluate dynamic response of the slope subjected simultaneously to seismic forces and variable groundwater conditions. Shaking table test is conducted to analyze the failure mode and verify the accuracy of the finite element method results. The research results show that dynamic response values of the slope have different variation rules under near and far field earthquakes. And the damage location and pattern of the slope are different in varying groundwater conditions. The destruction starts at the top of the slope when the slope is in no groundwater, which shows that the slope appears obvious whipping effect under the earthquake. The destruction starts at the toe of the slope when the slope is in the high groundwater levels. Meanwhile, the top of the slope shows obvious seismic subsidence phenomenon after earthquake. Furthermore, the existence of the groundwater has a certain effect of damping. PMID:26560103

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 at sites in parts of California.

Earthquakes, November-December 1973

USGS Publications Warehouse

Person, W.J.

1974-01-01

Other parts of the world suffered fatalities and significant damage from earthquakes. In Iran, an earthquake killed one person, injured many, and destroyed a number of homes. Earthquake fatalities also occurred in the Azores and in Algeria. 

Earthquakes in Arkansas and vicinity 1699-2010

USGS Publications Warehouse

Dart, Richard L.; Ausbrooks, Scott M.

2011-01-01

This map summarizes approximately 300 years of earthquake activity in Arkansas. It is one in a series of similar State earthquake history maps. Work on the Arkansas map was done in collaboration with the Arkansas Geological Survey. The earthquake data plotted on the map are from several sources: the Arkansas Geological Survey, the Center for Earthquake Research and Information, the National Center for Earthquake Engineering Research, and the Mississippi Department of Environmental Quality. In addition to earthquake locations, other materials presented include seismic hazard and isoseismal maps and related text. Earthquakes are a legitimate concern in Arkansas and parts of adjacent states. Arkansas has undergone a number of significant felt earthquakes since 1811. At least two of these events caused property damage: a magnitude 4.7 earthquake in 1931, and a magnitude 4.3 earthquake in 1967. The map shows all historical and instrumentally located earthquakes in Arkansas and vicinity between 1811 and 2010. The largest historic earthquake in the vicinity of the State was an intensity XI event, on December 16, 1811; the first earthquake in the New Madrid sequence. This violent event and the earthquakes that followed caused considerable damage to the then sparsely settled region.

The 17 July 2006 Tsunami earthquake in West Java, Indonesia

USGS Publications Warehouse

Mori, J.; Mooney, W.D.; Afnimar,; Kurniawan, S.; Anaya, A.I.; Widiyantoro, S.

2007-01-01

A tsunami earthquake (Mw = 7.7) occurred south of Java on 17 July 2006. The event produced relatively low levels of high-frequency radiation, and local felt reports indicated only weak shaking in Java. There was no ground motion damage from the earthquake, but there was extensive damage and loss of life from the tsunami along 250 km of the southern coasts of West Java and Central Java. An inspection of the area a few days after the earthquake showed extensive damage to wooden and unreinforced masonry buildings that were located within several hundred meters of the coast. Since there was no tsunami warning system in place, efforts to escape the large waves depended on how people reacted to the earthquake shaking, which was only weakly felt in the coastal areas. This experience emphasizes the need for adequate tsunami warning systems for the Indian Ocean region.

Predicting the spatial extent of liquefaction from geospatial and earthquake specific parameters

USGS Publications Warehouse

Zhu, Jing; Baise, Laurie G.; Thompson, Eric M.; Wald, David J.; Knudsen, Keith L.; Deodatis, George; Ellingwood, Bruce R.; Frangopol, Dan M.

2014-01-01

The spatially extensive damage from the 2010-2011 Christchurch, New Zealand earthquake events are a reminder of the need for liquefaction hazard maps for anticipating damage from future earthquakes. Liquefaction hazard mapping as traditionally relied on detailed geologic mapping and expensive site studies. These traditional techniques are difficult to apply globally for rapid response or loss estimation. We have developed a logistic regression model to predict the probability of liquefaction occurrence in coastal sedimentary areas as a function of simple and globally available geospatial features (e.g., derived from digital elevation models) and standard earthquake-specific intensity data (e.g., peak ground acceleration). Some of the geospatial explanatory variables that we consider are taken from the hydrology community, which has a long tradition of using remotely sensed data as proxies for subsurface parameters. As a result of using high resolution, remotely-sensed, and spatially continuous data as a proxy for important subsurface parameters such as soil density and soil saturation, and by using a probabilistic modeling framework, our liquefaction model inherently includes the natural spatial variability of liquefaction occurrence and provides an estimate of spatial extent of liquefaction for a given earthquake. To provide a quantitative check on how the predicted probabilities relate to spatial extent of liquefaction, we report the frequency of observed liquefaction features within a range of predicted probabilities. The percentage of liquefaction is the areal extent of observed liquefaction within a given probability contour. The regional model and the results show that there is a strong relationship between the predicted probability and the observed percentage of liquefaction. Visual inspection of the probability contours for each event also indicates that the pattern of liquefaction is well represented by the model.

Chapter A. The Loma Prieta, California, Earthquake of October 17, 1989 - Strong Ground Motion

USGS Publications Warehouse

Borcherdt, Roger D.

1994-01-01

Strong ground motion generated by the Loma Prieta, Calif., earthquake (MS~7.1) of October 17, 1989, resulted in at least 63 deaths, more than 3,757 injuries, and damage estimated to exceed $5.9 billion. Strong ground motion severely damaged critical lifelines (freeway overpasses, bridges, and pipelines), caused severe damage to poorly constructed buildings, and induced a significant number of ground failures associated with liquefaction and landsliding. It also caused a significant proportion of the damage and loss of life at distances as far as 100 km from the epicenter. Consequently, understanding the characteristics of the strong ground motion associated with the earthquake is fundamental to understanding the earthquake's devastating impact on society. The papers assembled in this chapter address this problem. Damage to vulnerable structures from the earthquake varied substantially with the distance from the causative fault and the type of underlying geologic deposits. Most of the damage and loss of life occurred in areas underlain by 'soft soil'. Quantifying these effects is important for understanding the tragic concentrations of damage in such areas as Santa Cruz and the Marina and Embarcadero Districts of San Francisco, and the failures of the San Francisco-Oakland Bay Bridge and the Interstate Highway 880 overpass. Most importantly, understanding these effects is a necessary prerequisite for improving mitigation measures for larger earthquakes likely to occur much closer to densely urbanized areas in the San Francisco Bay region. The earthquake generated an especially important data set for understanding variations in the severity of strong ground motion. Instrumental strong-motion recordings were obtained at 131 sites located from about 6 to 175 km from the rupture zone. This set of recordings, the largest yet collected for an event of this size, was obtained from sites on various geologic deposits, including a unique set on 'soft soil' deposits (artificial fill and bay mud). These exceptional ground-motion data are used by the authors of the papers in this chapter to infer radiation characteristics of the earthquake source, identify dominant propagation characteristics of the Earth?s crust, quantify amplification characteristics of near-surface geologic deposits, develop general amplification factors for site-dependent building-code provisions, and revise earthquake-hazard assessments for the San Francisco Bay region. Interpretations of additional data recorded in well-instrumented buildings, dams, and freeway overpasses are provided in other chapters of this report.

Rapid Assessment of Seismic Vulnerability in Palestinian Refugee Camps

NASA Astrophysics Data System (ADS)

Al-Dabbeek, Jalal N.; El-Kelani, Radwan J.

Studies of historical and recorded earthquakes in Palestine demonstrate that damaging earthquakes are occurring frequently along the Dead Sea Transform: Earthquake of 11 July 1927 (ML 6.2), Earthquake of 11 February 2004 (ML 5.2). In order to reduce seismic vulnerability of buildings, losses in lives, properties and infrastructures, an attempt was made to estimate the percentage of damage degrees and losses at selected refugee camps: Al Ama`ri, Balata and Dhaishe. Assessing the vulnerability classes of building structures was carried out according to the European Macro-Seismic Scale 1998 (EMS-98) and the Fedral Emergency Management Agency (FEMA). The rapid assessment results showed that very heavy structural and non structural damages will occur in the common buildings of the investigated Refugee Camps (many buildings will suffer from damages grades 4 and 5). Bad quality of buildings in terms of design and construction, lack of uniformity, absence of spaces between the building and the limited width of roads will definitely increase the seismic vulnerability under the influence of moderate-strong (M 6-7) earthquakes in the future.

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. The sensitivity analysis of the model results to the variation in basic parameters shows that the maximum magnitude has the most significant impact on the hazard, especially for long forecast periods.

Road Damage Extraction from Post-Earthquake Uav Images Assisted by Vector Data

NASA Astrophysics Data System (ADS)

Chen, Z.; Dou, A.

2018-04-01

Extraction of road damage information after earthquake has been regarded as urgent mission. To collect information about stricken areas, Unmanned Aerial Vehicle can be used to obtain images rapidly. This paper put forward a novel method to detect road damage and bring forward a coefficient to assess road accessibility. With the assistance of vector road data, image data of the Jiuzhaigou Ms7.0 Earthquake is tested. In the first, the image is clipped according to vector buffer. Then a large-scale segmentation is applied to remove irrelevant objects. Thirdly, statistics of road features are analysed, and damage information is extracted. Combining with the on-filed investigation, the extraction result is effective.

The impact of earthquakes on the city of Aigio in Greece. Urban planning as a factor in mitigating seismic damage.

NASA Astrophysics Data System (ADS)

Athanasopoulou, Evanthia; Despoiniadou, Varvara; Dritsos, Stefanos

2008-07-01

This paper examines the effects of the mortal earthquake on the city of Aigio in Greece in 1995, with particular focus on urbanization and planning policies. It is based on interviews with experts and surveys on damage to buildings following this earthquake. The analysis takes into account several factors, such as exact location, land use, construction period and the height of damaged buildings. Furthermore, the relationship between the seismic damage and the postseismic construction development of Aigio is examined and the conclusion is reached that the Greek urban planning system needs to be better organized to prepare for seismic damage. To this end, the paper recommends a five-point discussion agenda for applying local planning to seismic mitigation.

Repair of earthquake-damaged bridge columns with interlocking spirals and fractured bars.

DOT National Transportation Integrated Search

2014-07-01

During earthquakes, reinforced concrete (RC) bridge columns may experience different levels of damage such as cracking, spalling, or crushing of concrete and yielding, buckling, or fracture of reinforcing bars. Although several repair options exist f...

Visual inspection & capacity assessment of earthquake damaged reinforced concrete bridge elements.

DOT National Transportation Integrated Search

2008-11-01

The overarching objective of this project was to produce standard procedures and associated training materials, for the conduct of post-earthquake visual inspection and capacity assessment of damaged reinforced concrete (RC) bridges where the procedu...

Evaluation of long carbon fiber reinforced concrete to mitigate earthquake damage of infrastructure components.

DOT National Transportation Integrated Search

2013-06-01

The proposed study involves investigating long carbon fiber reinforced concrete as a method of mitigating earthquake damage to : bridges and other infrastructure components. Long carbon fiber reinforced concrete has demonstrated significant resistanc...

Study of Earthquake Disaster Prediction System of Langfang city Based on GIS

NASA Astrophysics Data System (ADS)

Huang, Meng; Zhang, Dian; Li, Pan; Zhang, YunHui; Zhang, RuoFei

2017-07-01

In this paper, according to the status of China’s need to improve the ability of earthquake disaster prevention, this paper puts forward the implementation plan of earthquake disaster prediction system of Langfang city based on GIS. Based on the GIS spatial database, coordinate transformation technology, GIS spatial analysis technology and PHP development technology, the seismic damage factor algorithm is used to predict the damage of the city under different intensity earthquake disaster conditions. The earthquake disaster prediction system of Langfang city is based on the B / S system architecture. Degree and spatial distribution and two-dimensional visualization display, comprehensive query analysis and efficient auxiliary decision-making function to determine the weak earthquake in the city and rapid warning. The system has realized the transformation of the city’s earthquake disaster reduction work from static planning to dynamic management, and improved the city’s earthquake and disaster prevention capability.

Rapid Field Response to the 3 September 2016 M5.8 Earthquake Near Pawnee, Oklahoma: Summary of Structural Damage and Liquefaction Observations

NASA Astrophysics Data System (ADS)

Bennett, S. E. K.; Streig, A. R.; Chang, J. C.; Hornsby, K. T.; Woelfel, I. E.; Andrews, R. D.; Briggs, R. W.; McNamara, D. E.; Williams, R. A.; Wald, D. J.

2016-12-01

The Mw5.8 Pawnee, Oklahoma earthquake occurred on 03 September 2016 (07:02:44 local time; depth 5.6 km) in a rural, sparsely populated area. The USGS, Mw-phase moment tensor indicated slip occurred on a sub-vertical fault plane, striking WNW or NNE. Relocations of this mainshock and a dozen aftershocks (Mw 2.5-3.6) in the day following the event were broadly aligned along a WNW trend. These data, along with USGS `Did You Feel It?' and ShakeMap products, helped guide our field response. Our team arrived to the epicentral region 10 hours after the mainshock and spent the next 1.5 days examining 60 km of paved and dirt roads across a 40 km2 area for evidence of surface deformation, liquefaction, and structural damage. We completed a 2 km-long, NNE transect on foot centered on the epicenter, perpendicular to the suspected WNW-striking source fault. No surface rupture was observed during our reconnaissance surveys. We interviewed 10 residents within a 1-6 km radius of the epicenter, who reported up to 30 seconds of shaking. Structural damage was common and ranged from minor to moderate. Failure and collapse of masonry chimneys and exterior house facades made of stone or brick was common near the epicenter, yet a few were undamaged. At several locations, damage patterns suggest an E-W shaking direction; for example, only the western wall of a century-old unreinforced brick storage building failed, elevated fuel tanks shook E-W, and most metal straps securing a trailer home to its cinder-block foundation were sheared in an E-W direction. One earthquake-related injury was caused by chimney bricks that struck a man on the head. Strong ground motion cracked foundations and interior walls at many homes near the epicenter. Minor ground settlement and ground cracking was observed in artificial fill surrounding houses and along the crests of small earthen dams. A large barn fire was attributed to the earthquake. Landowners reported sand blows in farm fields underlain by sandy floodplain deposits 5-10 km from the epicenter. Subsequent site visits and examination of post-event WorldView-1 satellite imagery confirmed reports of fresh liquefaction, but we were unable to identify additional liquefaction features. The sparse population in the epicentral region appears to have averted widespread damage from this earthquake.

ANALYSIS ON THE GROUND DESTROYED FEATURES AND TECTONIC STRESS FIELD OF THE 2008 WENCHUAN EARTHQUAKE AND OUR TREATING TACTICS

NASA Astrophysics Data System (ADS)

Guo, Y.; Wang, H.; Deng, Z.; You, H.

2009-12-01

To research the ground destroyed features and tectonic stress field of the 2008 Wenchuan Earthquake, we went the earthquake-hazard area, Hongkou Town in Dujiangyan City, Yingxiu Town in Wenchuan County, Bailu Town in Pengzhou City, Yinghua Town in Shifang City, Hanwang Town in Mianzhu City and Beichuan Cit early and late twice in 2008. The geological survey was made. Firstly, the ground destroyed features of the Wenchuan Earthquake around both Yingxiu - Beichuan Fracture and Guanxian - Jiangyou Fracture were analyzed. They mainly display as the ground crack ground, road steep slope, ground deformation, road rise high and deformation, road staggering and rupture, etc. Besides, the Wenchuan Earthquake resulted in the great deal of building collapse and lots of bridges damage even break down; It can be seen that the first floor of the building disappeared or damaged seriously; Some building still stood there although damaged by the earthquake; A few of building was damaged slightly and kept intact structure. Furthermore, the earthquake caused earth slide, mudflow and rolling stone, which lead to the building destroyed seriously, river blocked up, the life line engineering destroyed. Secondly, the phenomena of the ground destroy were analyzed preliminarily. The seismic intensity was determined based on the field investigation. The damaged situation of the construction was concluded. Based on the principle of structure geology and making use of the Stereographic projection, the stress field was analyzed according to the attitude, structural nature and relations among the fracture, fault scratch and joint fissure as well as the characteristics of ground deformation thirdly. The geodynamics of the 2008 Wenchuan Earthquake are probed into preliminarily. The main compressive stress (the maximum main stress) σ1 took Northeast by east direction, and the main tensile stress (the minimum main stress)σ3 took Northwest by north direction. The main fracture shows as the right-lateral thrust fracture. The general horizontal diminution and the vertical upheaval of the ground are discussed. At last, the paper compared the relationship between the ground damage and the fracture in the area hit by the 2008 Wenchuan Earthquake. The method to avoid and mitigate the loss of treasure and life caused by the earthquake is proposed. The chief aspects that require the more attention for the reconstruction after disaster are given.

GeoNet's `Felt Rapid': Collecting What Is Needed, When You Need It, No More, No Less. Rapid, Volumous Data For Response Versus Detailed, Precise Data For Research

NASA Astrophysics Data System (ADS)

Little, C. L.; McBride, S.; Balfour, N.

2016-12-01

New Zealand's geohazard monitoring agency, GeoNet, recently implemented `Felt Rapid': earthquake felt reporting that is quick and simple. GeoNet locates 20,000 earthquakes each year with hundreds of those reported as being felt. Starting in the late 1800s, the New Zealand public has become adept at completing felt reports but feedback since the Canterbury Earthquake Sequence suggested that traditional felt reporting was not meeting researchers' or the public's needs. GeoNet required something rapid, adaptable and robust. The solution was Felt Rapid, a mobile app and website where respondents simply pick from 6 cartoon images - representing Modified Mercalli Intensity (MMI) 3-8 - that best aligned to what they felt. For the last decade, felt reporting has been conducted via the GeoNet website, with additional targeted surveys after damaging earthquakes. The vast majority of the submitted felt reports were for earthquakes too small to cause damage, as these are by far the most frequent. Reports from small events are of little interest to researchers who are only concerned with damaging, MMI6 and above. However, we found that when damaging earthquakes did occur, such as Christchurch's M6.3, they were only sparsely reported (3,776 reports). Understandably, sitting at a computer and completing a lengthy online form wasn't a priority for people after a devastating earthquake. With Felt Rapid, reporting has to be completed within an hour of an earthquake, the use of GeoNet's automatically compiled felt reporting maps had evolved; their main purpose is immediate assessment of an earthquake's impact on populations, and is used by Civil Defence agencies. Reports are immediately displayed on an interactive map via the website and mobile app. With over 250,000 users this provides rapid and robust information regarding the experienced shaking. When a damaging earthquake occurs and researchers want to collect important and rare damaging felt reports, a separate in-depth survey is commissioned targeted to areas that experienced the highest levels of shaking. These surveys will be distributed via a range of mediums including posted as well an online call for submissions. GeoNet maintains an engaged and trusting community via social media channels which makes these calls for submissions effective.

Fear based Education or Curiosity based Education as an Example of Earthquake and Natural Disaster Education: Results of Statistical Study in Primary Schools in Istanbul-Turkey

NASA Astrophysics Data System (ADS)

Ozcep, T.; Ozcep, F.

2012-04-01

Natural disaster reduction focuses on the urgent need for prevention activities to reduce loss of life, damage to property, infrastructure and environment, and the social and economic disruption caused by natural hazards. One of the most important factors in reduction of the potential damage of earthquakes is trained manpower. To understanding the causes of earthquakes and other natural phenomena (landslides, avalanches, floods, volcanoes, etc.) is one of the pre-conditions to show a conscious behavior. The aim of the study is to analysis and to investigate, how earthquakes and other natural phenomena are perceived by the students and the possible consequences of this perception, and their effects of reducing earthquake damage. One of the crucial questions is that is our education system fear or curiosity based education system? Effects of the damages due to earthquakes have led to look like a fear subject. In fact, due to the results of the effects, the earthquakes are perceived scary phenomena. In the first stage of the project, the learning (or perception) levels of earthquakes and other natural disasters for the students of primary school are investigated with a survey. Aim of this survey study of earthquakes and other natural phenomena is that have the students fear based or curiosity based approaching to the earthquakes and other natural events. In the second stage of the project, the path obtained by the survey are evaluated with the statistical point of approach. A questionnaire associated with earthquakes and natural disasters are applied to primary school students (that total number of them is approximately 700 pupils) to measure the curiosity and/or fear levels. The questionnaire consists of 17 questions related to natural disasters. The questions are: "What is the Earthquake ?", "What is power behind earthquake?", "What is the mental response during the earthquake ?", "Did we take lesson from earthquake's results ?", "Are you afraid of earthquake ?", "Could earthquake be predicted ?", "Does earthquake kill people or buildings ?", "What is fault?", "Who is earthquake scientist?", "Are the Moon, Sun and other planets caused the earthquake?", "Does the weather conditions trigger the earthquake?", "What is the cause of tsunami?", "What is cause of the flood?", " What is the cause of volcanic eruption?", "What is cause of the landslide?", "What is the cause of disasters?", "What is your feeling about the earthquake; curiosity or fear?". Answers of these questions are evaluated. In the result, the primary school students think that earthquakes and other events are both religious and scientific origin. As example; the answers of "What is your feeling about the earthquake; corusity or fear?" question are replied 81 % Fear and %19 Curiosity.

Recent damaging earthquakes in Japan, 2003-2008

USGS Publications Warehouse

Kayen, Robert E

2008-01-01

During the last six years, from 2003-2008, Japan has been struck by three significant and damaging earthquakes: The most recent M6.6 Niigata Chuetsu Oki earthquake of July 16, 2007 off the coast of Kashiwazaki City, Japan; The M6.6 Niigata Chuetsu earthquake of October 23, 2004, located in Niigata Prefecture in the central Uonuma Hills; and the M8.0 Tokachi Oki Earthquake of September 26, 2003 effecting southeastern Hokkaido Prefecture. These earthquakes stand out among many in a very active period of seismicity in Japan. Within the upper 100 km of the crust during this period, Japan experienced 472 earthquakes of magnitude 6, or greater. Both Niigata events affected the south-central region of Tohoku Japan, and the Tokachi-Oki earthquake affected a broad region of the continental shelf and slope southeast of the Island of Hokkaido. This report is synthesized from the work of scores of Japanese and US researchers who led and participated in post-earthquake reconnaissance of these earthquakes: their noteworthy and valuable contributions are listed in an extended acknowledgements section at the end of the paper. During the Niigata Chuetsu Oki event of 2007, damage to the Kashiwazaki-Kariwa nuclear power plant, structures, infrastructure, and ground were primarily the product of two factors: (1) high intensity motions from this moderate-sized shallow event, and (2) soft, poor performing, or liquefiable soils in the coastal region of southwestern Niigata Prefecture. Structural and geotechnical damage along the slopes of dunes was ubiquitous in the Kashiwazaki-Kariwa region. The 2004 Niigata Chuetsu Earthquake was the most significant to affect Japan since the 1995 Kobe earthquake. Forty people were killed, almost 3,000 were injured, and many hundreds of landslides destroyed entire upland villages. Landslides were of all types; some dammed streams, temporarily creating lakes threatening to overtop their new embankments and cause flash floods and mudslides. The numerous landslides resulted, in part, from heavy rain associated with Typhoon Tokage. The earthquake forced more than 100,000 people into temporary shelters, and as many as 10,000 displaced from their upland homes for several years. Total damages was estimated by Japanese authorities at US$40 billion, making this the second most costly disaster in history, after the 1995 Kobe earth-quake. The 2003 Tokachi-Oki earthquake was the third event of magnitude 8.0+ to strike the southeastern portion of Hokkaido in the last 50 years. The event produced tsunami run-ups along the shoreline of southern Hokkaido that reached maximum heights of 4 meters. Accelerations recorded by seismic networks of Hokkaido indicated a high intensity motion region from Hiroo area to Kushiro City, with a PGA values in the range of 0.35 to 0.6g. Despite high acceleration levels, the observed ground failure, liquefaction, structural, port, and lifeline damages were remarkably light.

Public participation in reconstruction after the earthquakes in Friuli (Italy) and the Upper Soca Valley (Slovenia) in 1976, 1998, and 2004

NASA Astrophysics Data System (ADS)

Pipan, P.

2012-04-01

Northern Friuli (in northeast Italy) and the Upper Soča Valley (in northwest Slovenia) are extremely seismically active. The earthquakes of 6 May and 15 September 1976, with an epicenter in the Venzone area, claimed 939 lives in Italy and 157,000 people were left homeless. The same two earthquakes affected northwest Slovenia, which was still part of communist Yugoslavia at the time; they did not claim any lives, but they damaged 12,000 buildings and 13,000 people were left homeless. The "Easter Earthquake" of 12 April 1998, with an epicenter in the Krn Mountains, damaged 4,000 structures in Slovenia, among which nearly 1,500 had to be completely rebuilt. Even though there was noticeably less damage than in the 1976 earthquakes, in some settlements more than 80% of the houses were damaged. The same area was hit by another earthquake on 12 July 2004, which damaged nearly 2,000 structures, including some that had already been repaired after the 1998 earthquake. More than three decades after the 1976 earthquakes, a qualitative study was carried out on public participation in rebuilding after these earthquakes and public influence on the success of rebuilding. The research is based on studies of cases of individual settlements in Italy and Slovenia, where in-depth interviews were conducted with relevant persons that had been directly involved in the post-earthquake rebuilding efforts. This article highlights six case studies ranked on Arnstein's ladder of citizen participation. Examples from Italy include Venzone, Portis, and Resia for the 1976 earthquakes, and examples from Slovenia include Breginj for the 1976 earthquakes, Drežni\\vske Ravne for the 1998 earthquake, and Čezsoča for the 1998 and 2004 earthquakes. Alongside various political, legislative, and administrative circumstances, a responsible citizenry was also an important factor. In the case of Venzone, the majority of the residents and stakeholders had a positive influence on the preservation of cultural heritage because they limited individuals' negative impact and successfully resisted the municipal authorities' inclination to quickly rebuild after the earthquake, as was done in Breginj. Portis is a good example of the local community's great success in agreeing on how to rebuild their settlement and also carrying this out completely autonomously. For the Municipality of Resia, as a weak local community, responsibility for rebuilding after the earthquake was too much to handle. Because of the large extent of the damage and ineffective management of reconstruction, rebuilding was only completed two decades later. In the case of the preservation of cultural heritage in Breginj, the local community was divided, and the municipality's responsibility for rebuilding was insufficiently funded by the state, which also censored media reports on the failure to preserve cultural heritage. Drežni\\vske Ravne is a case of successful agreement with the residents in preparing a management plan for post-earthquake reconstruction of the affected settlement. Unfortunately, due to a lack of state resources, the management plan was not completely carried out. Čezsoča is a case in which the warnings and dissatisfaction expressed by the residents about improper rebuilding after the 1998 earthquake were confirmed by the 2004 earthquake.

ShakeCast Manual

USGS Publications Warehouse

Lin, Kuo-Wan; Wald, David J.

2008-01-01

ShakeCast is a freely available, post-earthquake situational awareness application that automatically retrieves earthquake shaking data from ShakeMap, compares intensity measures against users? facilities, and generates potential damage assessment notifications, facility damage maps, and other Web-based products for emergency managers and responders.

Accelerations from the September 5, 2012 (Mw=7.6) Nicoya, Costa Rica Earthquake

NASA Astrophysics Data System (ADS)

Simila, G. W.; Quintero, R.; Burgoa, B.; Mohammadebrahim, E.; Segura, J.

2013-05-01

Since 1984, the Seismic Network of the Volcanological and Seismological Observatory of Costa Rica, Universidad Nacional (OVSICORI-UNA) has been recording and registering the seismicity in Costa Rica. Before September 2012, the earthquakes registered by this seismic network in northwestern Costa Rica were moderate to small, except the Cóbano earthquake of March 25, 1990, 13:23, Mw 7.3, lat. 9.648, long. 84.913, depth 20 km; a subduction quake at the entrance of the Gulf of Nicoya and generated peak intensities in the range of MM = VIII near the epicentral area and VI-VII in the Central Valley of Costa Rica. Six years before the installation of the seismic network, OVSICORI-UNA registered two subduction earthquakes in northwestern Costa Rica, specifically on August 23, 1978, at 00:38:32 and 00:50:29 with magnitudes Mw 7.0 (HRVD), Ms 7.0 (ISC) and depths of 58 and 69 km, respectively (EHB Bulletin). On September 5, 2012, at 14:42:02.8 UTC, the seismic network OVSICORI-UNA registered another large subduction earthquake in Nicoya peninsula, northwestern Costa Rica, located 29 km south of Samara, with a depth of 21 km and magnitude Mw 7.6, lat. 9.6392, long. 85.6167. This earthquake was caused by the subduction of the Cocos plate under the Caribbean plate in northwestern Costa Rica. This earthquake was felt throughout the country and also in much of Nicaragua. The instrumental intensity map for the Nicoya earthquake indicates that the earthquake was felt with an intensity of VII-VIII in the Puntarenas and Nicoya Peninsulas, in an area between Liberia, Cañas, Puntarenas, Cabo Blanco, Carrillo, Garza, Sardinal, and Tamarindo in Guanacaste; Nicoya city being the place where the maximum reported intensity of VIII is most notable. An intensity of VIII indicates that damage estimates are moderate to severe, and intensity VII indicates that damage estimates are moderate. According to the National Emergency Commission of Costa Rica, 371 affected communities were reported; most reports were of damage to homes, bridges, roads, aqueducts, schools and public buildings. There were 12 structures reported with damages in hospitals and health care sites, specifically in Hojancha, Nandayure, Nicoya, Santa Cruz and Puntarenas. There are no reports of deaths from the earthquake and only 78 injured and a total of 1474 people mobilized, which includes hospital evacuations and preventive transfers. 223 schools were reported with various damages, mostly in Santa Cruz, Nicoya, Carrillo, Nandayure, and Puntarenas. A total of 98 homes were reported with severe damage, 805 with moderate damage and 87 with minor damage. In general, the buildings in the Nicoya Peninsula (where the highest intensities were reported) endured the Nicoya Earthquake. Also, acceleration data from OVSICORI, UCR, LIS-UCR, and the Seismic Strong Motion Array Project (SSMAP) show a range of accelerations (500 - 10 cm/sec2) for distance range of 30-250 km, respectively.

A Crowdsourcing-based Taiwan Scientific Earthquake Reporting System

NASA Astrophysics Data System (ADS)

Liang, W. T.; Lee, J. C.; Lee, C. F.

2017-12-01

To collect immediately field observations for any earthquake-induced ground damages, such as surface fault rupture, landslide, rock fall, liquefaction, and landslide-triggered dam or lake, etc., we are developing an earthquake damage reporting system which particularly relies on school teachers as volunteers after taking a series of training courses organized by this project. This Taiwan Scientific Earthquake Reporting (TSER) system is based on the Ushahidi mapping platform, which has been widely used for crowdsourcing on different purposes. Participants may add an app-like icon for mobile devices to this website at https://ies-tser.iis.sinica.edu.tw. Right after a potential damaging earthquake occurred in the Taiwan area, trained volunteers will be notified/dispatched to the source area to carry out field surveys and to describe the ground damages through this system. If the internet is available, they may also upload some relevant images in the field right away. This collected information will be shared with all public after a quick screen by the on-duty scientists. To prepare for the next strong earthquake, we set up a specific project on TSER for sharing spectacular/remarkable geologic features wherever possible. This is to help volunteers get used to this system and share any teachable material on this platform. This experimental, science-oriented crowdsourcing system was launched early this year. Together with a DYFI-like intensity reporting system, Taiwan Quake-Catcher Network, and some online games and teaching materials, the citizen seismology has been much improved in Taiwan in the last decade. All these constructed products are now either operated or promoted at the Taiwan Earthquake Research Center (TEC). With these newly developed platforms and materials, we are aiming not only to raise the earthquake awareness and preparedness, but also to encourage public participation in earthquake science in Taiwan.

Landslide Distribution, Damage and Land Use Interactions During the 2004 Chuetsu Earthquake

NASA Astrophysics Data System (ADS)

Sidle, R. C.; Trandafir, A. C.; Kamai, T.

2005-05-01

A series of earthquakes struck Niigata Prefecture, Japan, on 23 October 2004 killing about 40 people and injuring about 3000. These earthquakes were characterized by a shallow focal depth (13 km) that generated strong levels of ground motion, resulting in extensive damage and thousands of landslides throughout the region. Most landslides on natural slopes occurred in the regional geological structure consisting of sandy siltstone and thin-bedded alternations of sandstone and siltstone. Earthquakes exacerbate such potential instabilities by the ground motion induced and the enhancement of pore water pressure in wet regoliths. The three strongest earthquakes occurred within a period of less than 40 minutes, and had sequential magnitudes (JMA) of 6.8, 6.3, and 6.5. The highest density of landslides (12/km2) was mapped within a 2.9 km radius of the M6.5 epicenter near Yamakoshi village; about 4 times higher density compared to the other epicenters located to the east and west. This higher density may be a consequence of the cumulative shaking effects associated with the two earlier earthquakes of M6.8 and 6.5, in addition to the topographic and geologic factors controlling the stability of the region. Roads, residential fills, agricultural terraces on hillslopes, and other earthworks increased the susceptibility of sites to slope failure. Numerous earthquake-induced failures in terraces and adjacent hillslopes around rice paddy fields occurred near Yamakoshi village. A housing development in Nagaoka city constructed on an old earthflow suffered from severe damage to fill slopes during the earthquake. Nearly saturated conditions in these deep fills together with poor drainage systems contributed to the landslide damages. Clearly, land use activities in rural and urban areas exacerbated the extent of earthquake-triggered landslides.

Post earthquake recovery in natural gas systems--1971 San Fernando Earthquake

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

Johnson, W.T. Jr.

1983-01-01

In this paper a concise summary of the post earthquake investigations for the 1971 San Fernando Earthquake is presented. The effects of the earthquake upon building and other above ground structures are briefly discussed. Then the damages and subsequent repairs in the natural gas systems are reported.

The 1748 Montesa (south-east Spain) earthquake, a singular event

NASA Astrophysics Data System (ADS)

Buforn, Elisa; Udías, Agustín; Sanz de Galdeano, Carlos

2015-04-01

The Montesa earthquakes of 1748 took place in the south-east region of the Iberian Peninsula. Its location falls somewhat outside the seismic active region of southern Spain. The main shock took place on the 23 of March and was followed by a series of aftershocks, the largest on the 2 of April. Despite of the large number of documents with descriptions of the damage produced by this earthquake it has not been the object of a detailed seismological study. Documents described the damage in about 100 towns and villages over a wide area and it was felt in Valencia, Alcoy and Cartagena. The castle of Montesa was totally destroyed and the town of Xàtiva suffered heavy damage. The source region with seismic intensity IX extends about 15 km from Sellent to Enguera, along a possible fault of NE-SW direction. This is a singular event because it occurred in an area with an assigned low seismic risk where in the past very few large earthquakes have happened. This earthquake shows that a destructive earthquake may happen in the future in this region. The area affected by the earthquake has today a high industrial and tourist development.

Izmit, Turkey 1999 Earthquake Interferogram

NASA Image and Video Library

2001-03-30

This image is an interferogram that was created using pairs of images taken by Synthetic Aperture Radar (SAR). The images, acquired at two different times, have been combined to measure surface deformation or changes that may have occurred during the time between data acquisition. The images were collected by the European Space Agency's Remote Sensing satellite (ERS-2) on 13 August 1999 and 17 September 1999 and were combined to produce these image maps of the apparent surface deformation, or changes, during and after the 17 August 1999 Izmit, Turkey earthquake. This magnitude 7.6 earthquake was the largest in 60 years in Turkey and caused extensive damage and loss of life. Each of the color contours of the interferogram represents 28 mm (1.1 inches) of motion towards the satellite, or about 70 mm (2.8 inches) of horizontal motion. White areas are outside the SAR image or water of seas and lakes. The North Anatolian Fault that broke during the Izmit earthquake moved more than 2.5 meters (8.1 feet) to produce the pattern measured by the interferogram. Thin red lines show the locations of fault breaks mapped on the surface. The SAR interferogram shows that the deformation and fault slip extended west of the surface faults, underneath the Gulf of Izmit. Thick black lines mark the fault rupture inferred from the SAR data. Scientists are using the SAR interferometry along with other data collected on the ground to estimate the pattern of slip that occurred during the Izmit earthquake. This then used to improve computer models that predict how this deformation transferred stress to other faults and to the continuation of the North Anatolian Fault, which extends to the west past the large city of Istanbul. These models show that the Izmit earthquake further increased the already high probability of a major earthquake near Istanbul. http://photojournal.jpl.nasa.gov/catalog/PIA00557

Izmit, Turkey 1999 Earthquake Interferogram

NASA Technical Reports Server (NTRS)

2001-01-01

This image is an interferogram that was created using pairs of images taken by Synthetic Aperture Radar (SAR). The images, acquired at two different times, have been combined to measure surface deformation or changes that may have occurred during the time between data acquisition. The images were collected by the European Space Agency's Remote Sensing satellite (ERS-2) on 13 August 1999 and 17 September 1999 and were combined to produce these image maps of the apparent surface deformation, or changes, during and after the 17 August 1999 Izmit, Turkey earthquake. This magnitude 7.6 earthquake was the largest in 60 years in Turkey and caused extensive damage and loss of life. Each of the color contours of the interferogram represents 28 mm (1.1 inches) of motion towards the satellite, or about 70 mm (2.8 inches) of horizontal motion. White areas are outside the SAR image or water of seas and lakes. The North Anatolian Fault that broke during the Izmit earthquake moved more than 2.5 meters (8.1 feet) to produce the pattern measured by the interferogram. Thin red lines show the locations of fault breaks mapped on the surface. The SAR interferogram shows that the deformation and fault slip extended west of the surface faults, underneath the Gulf of Izmit. Thick black lines mark the fault rupture inferred from the SAR data. Scientists are using the SAR interferometry along with other data collected on the ground to estimate the pattern of slip that occurred during the Izmit earthquake. This then used to improve computer models that predict how this deformation transferred stress to other faults and to the continuation of the North Anatolian Fault, which extends to the west past the large city of Istanbul. These models show that the Izmit earthquake further increased the already high probability of a major earthquake near Istanbul.

Using remote sensing to predict earthquake impacts

NASA Astrophysics Data System (ADS)

Fylaktos, Asimakis; Yfantidou, Anastasia

2017-09-01

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

Analysis of a school building damaged by the 2015 Ranau earthquake Malaysia

NASA Astrophysics Data System (ADS)

Takano, Shugo; Saito, Taiki

2017-10-01

On June 5th, 2015 a severe earthquake with a moment Magnitude of 6.0 occurred in Ranau, Malaysia. Depth of the epicenter is 10 km. Due to the earthquake, many facilities were damaged and 18 people were killed due to rockfalls [1]. Because the British Standard (BS) is adopted as a regulation for built buildings in Malaysia, the seismic force is not considered in the structural design. Therefore, the seismic resistance of Malaysian buildings is unclear. To secure the human life and building safety, it is important to grasp seismic resistance of the building. The objective of this study is to evaluate the seismic resistance of the existing buildings in Malaysia built by the British Standard. A school building that was damaged at the Ranau earthquake is selected as the target building. The building is a four story building and the ground floor is designed to be a parking space for the staff. The structural types are infill masonries where main frame is configured by reinforced concrete columns and beams and brick is installed inside the frame as walls. Analysis is performed using the STERA_3D software that is the software to analyze the seismic performance of buildings developed by one of the authors. Firstly, the natural period of the building is calculated and compared with the result of micro-tremor measurement. Secondly, the nonlinear push-over analysis was conducted to evaluate the horizontal load bearing capacity of the building. Thirdly, the earthquake response analysis was conducted using the time history acceleration data measured at the Ranau earthquake by the seismograph installed at Kota Kinabalu. By comparing the results of earthquake response analysis and the actual damage of the building, the reason that caused damage to the building is clarified.

Disparate Tectonic Settings of Devastating Earthquakes in Mexico, September 2017

NASA Astrophysics Data System (ADS)

Li, J.; Chen, W. P.; Ning, J.

2017-12-01

Large earthquakes associated with thrust faulting along the plate interface typically pose the highest seismic risk along subduction zones. However, both damaging earthquakes in Mexico of September 2017 are notable exceptions. The Tehuantepec event on the 8th (Mw 8.1) occurred just landward of the trench but is associated with normal faulting, akin to the large (Ms 8) historical event of 1931 that occurred about 200 km to the northwest along this subduction zone. The Puebla earthquake (on the 19th, Mw 7.1) occurred almost 300 km away from the trench where seismic imaging had indicated that the flat-lying slab steepens abruptly and plunges aseismically into the deep mantle. Here we show that both types of tectonic settings are in fact common along a large portion of the Mexican subduction zone, thus identifying source zones of potentially damaging earthquakes away from the plate interface. Additionally, modeling of broadband waveforms made clear that another significant event (Mw 6.1) on the 23rd, is associated with shallow normal faulting in the upper crust, not directly related to the two damaging earthquakes.

Estimating the residual axial load capacity of flexure-dominated reinforced concrete bridge columns.

DOT National Transportation Integrated Search

2014-08-01

Extreme events such as earthquakes have the potential to damage hundreds, if not thousands, of bridges on a : transportation network. Following an earthquake, the damaged bridges are inspected by engineers sequentially to : decide whether or not to c...

ShakeCast: Automating and Improving the Use of ShakeMap for Post-Earthquake Decision- Making and Response

NASA Astrophysics Data System (ADS)

Lin, K.; Wald, D. J.

2007-12-01

ShakeCast is a freely available, post-earthquake situational awareness application that automatically retrieves earthquake shaking data from ShakeMap, compares intensity measures against users" facilities, sends notifications of potential damage to responsible parties, and generates facility damage maps and other Web-based products for emergency managers and responders. ShakeMap, a tool used to portray the extent of potentially damaging shaking following an earthquake, provides overall information regarding the affected areas. When a potentially damaging earthquake occurs, utility and other lifeline managers, emergency responders, and other critical users have an urgent need for information about the impact on their particular facilities so they can make appropriate decisions and take quick actions to ensure safety and restore system functionality. To this end, ShakeCast estimates the potential damage to a user's widely distributed facilities by comparing the complex shaking distribution with the potentially highly variable damageability of their inventory to provide a simple, hierarchical list and maps showing structures or facilities most likely impacted. All ShakeMap and ShakeCast files and products are non-propriety to simplify interfacing with existing users" response tools and to encourage user-made enhancement to the software. ShakeCast uses standard RSS and HTTP requests to communicate with the USGS Web servers that host ShakeMaps, which are widely-distributed and heavily mirrored. The RSS approach allows ShakeCast users to initiate and receive selected ShakeMap products and information on software updates. To assess facility damage estimates, ShakeCast users can combine measured or estimated ground motion parameters with damage relationships that can be pre-computed, use one of these ground motion parameters as input, and produce a multi-state discrete output of damage likelihood. Presently three common approaches are being used to provide users with an indication of damage: HAZUS-based, intensity-based, and customized damage functions. Intensity-based thresholds are for locations with poorly established damage relationships; custom damage levels are for advanced ShakeCast users such as Caltrans which produces its own set of damage functions that correspond to the specific details of each California bridge or overpass in its jurisdiction. For users whose portfolio of structures is comprised of common, standard designs, ShakeCast offers a simplified structural damage-state estimation capability adapted from the HAZUS-MH earthquake module (NIBS and FEMA, 2003). Currently the simplified fragility settings consist of 128 combinations of HAZUS model building types, construction materials, building heights, and building-code eras.

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

Saragoni, G. Rodolfo

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

A smartphone application for earthquakes that matter!

NASA Astrophysics Data System (ADS)

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

2014-05-01

Smartphone applications have swiftly become one of the most popular tools for rapid reception of earthquake information for the public, some of them having been downloaded more than 1 million times! The advantages are obvious: wherever someone's own location is, they can be automatically informed when an earthquake has struck. Just by setting a magnitude threshold and an area of interest, there is no longer the need to browse the internet as the information reaches you automatically and instantaneously! One question remains: are the provided earthquake notifications always relevant for the public? What are the earthquakes that really matters to laypeople? One clue may be derived from some newspaper reports that show that a while after damaging earthquakes many eyewitnesses scrap the application they installed just after the mainshock. Why? Because either the magnitude threshold is set too high and many felt earthquakes are missed, or it is set too low and the majority of the notifications are related to unfelt earthquakes thereby only increasing anxiety among the population at each new update. Felt and damaging earthquakes are the ones that matter the most for the public (and authorities). They are the ones of societal importance even when of small magnitude. A smartphone application developed by EMSC (Euro-Med Seismological Centre) with the financial support of the Fondation MAIF aims at providing suitable notifications for earthquakes by collating different information threads covering tsunamigenic, potentially damaging and felt earthquakes. Tsunamigenic earthquakes are considered here to be those ones that are the subject of alert or information messages from the PTWC (Pacific Tsunami Warning Centre). While potentially damaging earthquakes are identified through an automated system called EQIA (Earthquake Qualitative Impact Assessment) developed and operated at EMSC. This rapidly assesses earthquake impact by comparing the population exposed to each expected level of shaking intensity with empirical models of fatality losses calibrated on past earthquakes in each country. Non-seismic detections and macroseismic questionnaires collected online are combined to identify as many as possible of the felt earthquakes regardless their magnitude. Non seismic detections include Twitter earthquake detections, developed by the US Geological Survey, where the number of tweets containing the keyword "earthquake" is monitored in real time and flashsourcing, developed by the EMSC, which detect traffic surges on its rapid earthquake information website caused by the natural convergence of eyewitnesses who rush to the Internet to investigate the cause of the shaking that they have just felt. All together, we estimate that the number of detected felt earthquakes is around 1 000 per year, compared with the 35 000 earthquakes annually reported by the EMSC! Felt events are already the subject of the web page "Latest significant earthquakes" on EMSC website (http://www.emsc-csem.org/Earthquake/significant_earthquakes.php) and of a dedicated Twitter service @LastQuake. We will present the identification process of the earthquakes that matter, the smartphone application itself (to be released in May) and its future evolutions.

Rapid Seismic Deployment for Capturing Aftershocks of the September 2017 Tehuantepec, Mexico (M=8.1) and Morelos-Puebla (M=7.1), Mexico Earthquakes

NASA Astrophysics Data System (ADS)

Velasco, A. A.; Karplus, M. S.; Dena, O.; Gonzalez-Huizar, H.; Husker, A. L.; Perez-Campos, X.; Calo, M.; Valdes, C. M.

2017-12-01

The September 7 Tehuantepec, Mexico (M=8.1) and the September 19 Morelos-Puebla, Mexico (M=7.1) earthquakes ruptured with extensional faulting within the Cocos Plate at 70-km and 50-km depth, as it subducts beneath the continental North American Plate. Both earthquakes caused significant damage and loss of life. These events were followed by a M=6.1 extensional earthquake at only 10-km depth in Oaxaca on September 23, 2017. While the Morelos-Puebla earthquake was likely too far away to be statically triggered by the Tehuantepec earthquake, initial Coulomb stress analyses show that the M=6.1 event may have been an aftershock of the Tehuantepec earthquake. Many questions remain about these earthquakes, including: Did the Cocos Plate earthquakes load the upper plate, and could they possibly trigger an equal or larger earthquake on the plate interface? Are these the result of plate bending? Do the aftershocks migrate to the locked zone in the subduction zone? Why did the intermediate depth earthquakes create so much damage? Are these earthquakes linked by dynamic stresses? Is it possible that a potential slow-slip event triggered both events? To address some of these questions, we deployed 10 broadband seismometers near the epicenter of the Tehuantepec, Mexico earthquake and 51 UTEP-owned nodes (5-Hz, 3-component geophones) to record aftershocks and augment networks deployed by the Universidad Nacional Autónoma de México (UNAM). The 10 broadband instruments will be deployed for 6 months, while the nodes were deployed 25 days. The relative ease-of-deployment and larger numbers of the nodes allowed us to deploy them quickly in the area near the M=6.1 Oaxaca earthquake, just a few days after that earthquake struck. We deployed them near the heavily-damaged cities of Juchitan, Ixtaltepec, and Ixtepec as well as in Tehuantepec and Salina Cruz, Oaxaca in order to test their capabilities for site characterization and aftershock studies. This is the first test of these instruments in a region heavily affected by aftershocks, outside of Oklahoma. Analysis of the nodal and broadband data will allow us to investigate fault geometries from aftershock locations, stress release and orientation from the determination of fault plane solutions, and site effects and characteristics in regions of extensive damage.

Surface and Subsurface Fault Displacements from the September 2010 Darfield (Canterbury) Earthquake

NASA Astrophysics Data System (ADS)

Meyers, B.; Furlong, K. P.; Hayes, G. P.; Herman, M. W.; Quigley, M.

2012-12-01

On September 3, 2010 a Magnitude 7.1 earthquake struck near Darfield, New Zealand. This was to be the first earthquake in an ongoing, damaging sequence near the city of Christchurch. The earthquake produced a surface rupture with measurable offsets of up to 5.3m along a 30km surface fault system. The spatial pattern of slip during this rupture has been determined by various groups using a range of approaches and several independent data sets. Surface fault rupture was measured in the field and fault slip at depth has been inferred from a seismologic finite fault model (FFM) and various geodetic observations including GPS and InSAR. Here we compare the observed segmented surface displacements with fault slip inferred from the other data. Measurements of the surface rupture show segmented faulting consistent with subsurface slip in the FFM. In the FFM, the main slip patch near the hypocenter can be directly correlated to the region of maximum surface displacement. The FFM and some evidence in the InSAR data also indicate that the Greendale fault system, the structure responsible for the bulk of the rupture, continues at depth closer towards Christchurch than is seen in surface rupture patterns. There is an additional 20km long patch with up to 3m of modeled slip seen in the eastern end of the inverted fault, offset to the south from the Greendale fault trace. This additional fault segment is consistent with a zone of aftershock activity of the main Darfield event, and with local patterns of strong motion. It thus appears that slip recorded at the surface does not describe the entire fault system. This eastward extension of the September rupture means that there is only a short segment of unruptured crust remaining along the entire fault system involved in the Canterbury earthquake sequence.

Earthquakes in Virginia and vicinity 1774 - 2004

USGS Publications Warehouse

Tarr, Arthur C.; Wheeler, Russell L.

2006-01-01

This map summarizes two and a third centuries of earthquake activity. The seismic history consists of letters, journals, diaries, and newspaper and scholarly articles that supplement seismograph recordings (seismograms) dating from the early twentieth century to the present. All of the pre-instrumental (historical) earthquakes were large enough to be felt by people or to cause shaking damage to buildings and their contents. Later, widespread use of seismographs meant that tremors too small or distant to be felt could be detected and accurately located. Earthquakes are a legitimate concern in Virginia and parts of adjacent States. Moderate earthquakes cause slight local damage somewhere in the map area about twice a decade on the average. Additionally, many buildings in the map area were constructed before earthquake protection was added to local building codes. The large map shows all historical and instrumentally located earthquakes from 1774 through 2004.

Overview of the critical disaster management challenges faced during Van 2011 earthquakes.

PubMed

Tolon, Mert; Yazgan, Ufuk; Ural, Derin N; Goss, Kay C

2014-01-01

On October 23, 2011, a M7.2 earthquake caused damage in a widespread area in the Van province located in eastern Turkey. This strong earthquake was followed by a M5.7 earthquake on November 9, 2011. This sequence of damaging earthquakes led to 644 fatalities. The management during and after these earthquake disaster imposed many critical challenges. In this article, an overview of these challenges is presented based on the observations by the authors in the aftermath of this disaster. This article presents the characteristics of 2011 Van earthquakes. Afterward, the key information related to the four main phases (ie, preparedness, mitigation, response, and recovery) of the disaster in Van is presented. The potential strategies that can be taken to improve the disaster management practice are identified, and a set of recommendations are proposed to improve the existing situation.

Developing ShakeCast statistical fragility analysis framework for rapid post-earthquake assessment

USGS Publications Warehouse

Lin, K.-W.; Wald, D.J.

2012-01-01

When an earthquake occurs, the U. S. Geological Survey (USGS) ShakeMap estimates the extent of potentially damaging shaking and provides overall information regarding the affected areas. The USGS ShakeCast system is a freely-available, post-earthquake situational awareness application that automatically retrieves earthquake shaking data from ShakeMap, compares intensity measures against users’ facilities, sends notifications of potential damage to responsible parties, and generates facility damage assessment maps and other web-based products for emergency managers and responders. We describe notable improvements of the ShakeMap and the ShakeCast applications. We present a design for comprehensive fragility implementation, integrating spatially-varying ground-motion uncertainties into fragility curves for ShakeCast operations. For each facility, an overall inspection priority (or damage assessment) is assigned on the basis of combined component-based fragility curves using pre-defined logic. While regular ShakeCast users receive overall inspection priority designations for each facility, engineers can access the full fragility analyses for further evaluation.

[Operating room during natural disaster: lessons from the 2011 Tohoku earthquake].

PubMed

Fukuda, Ikuo; Hashimoto, Hiroshi; Suzuki, Yasuyuki; Satomi, Susumu; Unno, Michiaki; Ohuchi, Noriaki; Nakaji, Shigeyuki

2012-03-01

Objective of this study is to clarify damages in operating rooms after the 2011 Tohoku Earthquake. To survey structural and non-structural damage in operating theaters, we sent questionnaires to 155 acute care hospitals in Tohoku area. Questionnaires were sent back from 105 hospitals (70.3%). Total of 280 patients were undergoing any kinds of operations during the earthquake and severe seismic tremor greater than JMA Seismic Intensity 6 hit 49 hospitals. Operating room staffs experienced life-threatening tremor in 41 hospitals. Blackout occurred but emergency electronic supply unit worked immediately in 81 out of 90 hospitals. However, emergency power plant did not work in 9 hospitals. During earthquake some materials fell from shelves in 44 hospitals and medical instruments fell down in 14 hospitals. In 5 hospitals, they experienced collapse of operating room wall or ceiling causing inability to maintain sterile operative field. Damage in electric power and water supply plus damage in logistics made many operating rooms difficult to perform routine surgery for several days. The 2011 Tohoku earthquake affected medical supply in wide area of Tohoku district and induced dysfunction of operating room. Supply-chain management of medical goods should be reconsidered to prepare severe natural disaster.

Analysis of the Impact of Fault Mechanism Radiation Patterns on Macroseismic Fields in the Epicentral Area of 1998 and 2004 Krn Mountains Earthquakes (NW Slovenia)

PubMed Central

2014-01-01

Two moderate magnitude (Mw = 5.6 and 5.2) earthquakes in Krn Mountains occurred in 1998 and 2004 which had maximum intensity VII-VIII and VI-VII EMS-98, respectively. Comparison of both macroseismic fields showed unexpected differences in the epicentral area which cannot be explained by site effects. Considerably, different distribution of the highest intensities can be noticed with respect to the strike of the seismogenic fault and in some localities even higher intensities have been estimated for the smaller earthquake. Although hypocentres of both earthquakes were only 2 km apart and were located on the same seismogenic Ravne fault, their focal mechanisms showed a slight difference: almost pure dextral strike-slip for the first event and a strike-slip with small reverse component on a steep fault plane for the second one. Seismotectonically the difference is explained as an active growth of the Ravne fault at its NW end. The radiation patterns of both events were studied to explain their possible impact on the observed variations in macroseismic fields and damage distribution. Radiation amplitude lobes were computed for three orthogonal directions: radial P, SV, and SH. The highest intensities of both earthquakes were systematically observed in directions of four (1998) or two (2004) large amplitude lobes in SH component (which corresponds mainly to Love waves), which have significantly different orientation for both events. On the other hand, radial P direction, which is almost purely symmetrical for the strike-slip mechanism of 1998 event, showed for the 2004 event that its small reverse component of movement has resulted in a very pronounced amplitude lobe in SW direction where two settlements are located which expressed higher intensities in the case of the 2004 event with respect to the 1998 one. Although both macroseismic fields are very complex due to influences of multiple earthquakes, retrofitting activity after 1998, site effects, and sparse distribution of settlements, unusual differences in observed intensities can be explained with different radiation patterns. PMID:24772011

Analysis of the impact of fault mechanism radiation patterns on macroseismic fields in the epicentral area of 1998 and 2004 Krn Mountains earthquakes (NW Slovenia).

PubMed

Gosar, Andrej

2014-01-01

Two moderate magnitude (Mw = 5.6 and 5.2) earthquakes in Krn Mountains occurred in 1998 and 2004 which had maximum intensity VII-VIII and VI-VII EMS-98, respectively. Comparison of both macroseismic fields showed unexpected differences in the epicentral area which cannot be explained by site effects. Considerably, different distribution of the highest intensities can be noticed with respect to the strike of the seismogenic fault and in some localities even higher intensities have been estimated for the smaller earthquake. Although hypocentres of both earthquakes were only 2 km apart and were located on the same seismogenic Ravne fault, their focal mechanisms showed a slight difference: almost pure dextral strike-slip for the first event and a strike-slip with small reverse component on a steep fault plane for the second one. Seismotectonically the difference is explained as an active growth of the Ravne fault at its NW end. The radiation patterns of both events were studied to explain their possible impact on the observed variations in macroseismic fields and damage distribution. Radiation amplitude lobes were computed for three orthogonal directions: radial P, SV, and SH. The highest intensities of both earthquakes were systematically observed in directions of four (1998) or two (2004) large amplitude lobes in SH component (which corresponds mainly to Love waves), which have significantly different orientation for both events. On the other hand, radial P direction, which is almost purely symmetrical for the strike-slip mechanism of 1998 event, showed for the 2004 event that its small reverse component of movement has resulted in a very pronounced amplitude lobe in SW direction where two settlements are located which expressed higher intensities in the case of the 2004 event with respect to the 1998 one. Although both macroseismic fields are very complex due to influences of multiple earthquakes, retrofitting activity after 1998, site effects, and sparse distribution of settlements, unusual differences in observed intensities can be explained with different radiation patterns.

A detailed study of the Pernik (Bulgaria) seismic sequence of 2012

NASA Astrophysics Data System (ADS)

Raykova, Plamena; Solakov, Dimcho; Simeonova, Stela; Dimitrova, Liliya

2014-05-01

A detailed study of the Pernik (Bulgaria) seismic sequence of 2012 D.Solakov, S.Simeonova ,I. Georgiev, P.Raykova, L.Dimitrova and V.Protopopova National Institute of Geophysics, Geodesy and Geography-BAS, Sofia, Bulgaria The spatial and temporal clustering of aftershocks is the dominant non-random element of seismicity, so that when aftershocks are removed, the remaining activity can be modelled (as first approximation) as a Poisson process. The properties of aftershock sequences (distinct cluster, for example; even aftershocks can have aftershocks) allow time-dependent prediction of aftershock probabilities. Consideration of recent earthquake sequences suggests that aftershocks to large earthquakes although they are still, by definition, smaller events, can be very damaging and should be addressed in emergence planning scenarios. Because of the factors such as location and radiation pattern and the cumulative nature of building damage, aftershocks can cause more damage than the main shock. An earthquake of moment magnitude 5.6 hit Sofia seismic zone, on May 22nd, 2012. The earthquake occurred in the vicinity of Pernik city, at about 25 km south west of the city of Sofia (the capital of Bulgaria). The event was followed by intensive activity. The active area is situated in the central part of western Bulgaria. That is the most populated (more than 1.2 mil. inhabitants), industrial and cultural region of Bulgaria. Seismicity in the zone is related to the marginal neotectonic faults of Sofia graben. The boundaries of the graben are represented by SE-NW fault system with expressive neotectonic activity. This zone is characterized by shallow earthquakes. The strongest known event in the region is the 1858 quake with intensity I0=9-10 MSK. The 1858 earthquake caused heavy destruction in the city of Sofia and the appearance of thermal spring. It is worth mentioning that the seismic sequence of May 2912 occurred in an area characterized by a long quiescence (of 95 years) for moderate events. Moreover, a reduced number of small earthquakes has also been registered in the recent past. The manifold purpose of this study is first to study spatial and temporal distribution of aftershocks than to analyze wave forms and to determine individual focal mechanisms of the largest shocks. Additionally, a joint hypocenter determination and composite focal mechanism of a large number of small aftershocks were carried out. Finally, the current state of stress in the considered region, obtained on the base of aftershock focal mechanisms, was compared with horizontal crustal movement inferred from GPS measurement.

Coulomb stress change sensitivity due to variability in mainshock source models and receiving fault parameters: A case study of the 2010-2011 Christchurch, New Zealand, earthquakes

USGS Publications Warehouse

Zhan, Zhongwen; Jin, Bikai; Wei, Shengji; Graves, Robert W.

2011-01-01

Strong aftershocks following major earthquakes present significant challenges for infrastructure recovery as well as for emergency rescue efforts. A tragic instance of this is the 22 February 2011 Mw 6.3 Christchurch aftershock in New Zealand, which caused more than 100 deaths while the 2010 Mw 7.1 Canterbury mainshock did not cause a single fatality (Figure 1). Therefore, substantial efforts have been directed toward understanding the generation mechanisms of aftershocks as well as mitigating hazards due to aftershocks. Among these efforts are the prediction of strong aftershocks, earthquake early warning, and aftershock probability assessment. Zhang et al. (1999) reported a successful case of strong aftershock prediction with precursory data such as changes in seismicity pattern, variation of b-value, and geomagnetic anomalies. However, official reports of such successful predictions in geophysical journals are extremely rare, implying that deterministic prediction of potentially damaging aftershocks is not necessarily more scientifically feasible than prediction of mainshocks.

Surface Deformation Due to the May 27, 1995 Sakhalin Earthquake and Related Events Measured by JERS-1 SAR Interferometry

NASA Technical Reports Server (NTRS)

Fielding, E. J.; Fujiwara, Satoshi; Hensley, S.; Rosen, P. A.; Tobita, Mikio; Shimada, Masanobu

1996-01-01

A large (M&subw;=7.0) earthquake on May 27, 1995 completely destroyed the town of Neftegorsk in the northern part of Sakhalin Island and caused more than 2000 human deaths. The shallow, right-lateral, strick-slip earthquake resulted in extensive surface ruptures and up to 7 m of horizontal displacement as reported by field workers. The sourthern part of the mainshock epicenter zone was imaged by the JERS-1 SAR (synthetic aperature radar) one month (April 28) before and two weeks after (June 11) the mainshock. Despite drastically changed surface conditions in the 44 days between the two images, due primarily to spring thaw, we obtained reasonably good interferometric correlation with the L-band (24 cm) SAR pair. The interoferogram records the distribution of deformation reflecting displacement during both the mainshock and aftershocks. The ability to map the deformation pattern can aid the assessment and mitigation of damage.

Characteristics of seismic and tsunami fragility of industries, revealed by the 2011 Tohoku-oki earthquake

NASA Astrophysics Data System (ADS)

Kuwahara, Y.; Hasegawa, I.; Yoshimi, M.; Namegaya, Y.; Horikawa, H.; Nakai, M.; Masuda, S.

2013-12-01

We have developed seismic and tsunami fragility curves of industries by using damage data of industrial companies, estimated strong motions and estimated tsunami heights of the 2011 Tohoku-oki earthquake. The damage data were obtained from 7,019 industrial companies, which responded to an inquiry survey to 30,000 companies carried out by the Regional Innovation Research Center of Tohoku University. As a damage level indicator for each company, we introduced a ratio of an economical damage of physical fixed assets excluding lands to previous balance of the physical fixed assets. The estimated strong motions of the 2011 Tohoku-oki earthquake at all the sites of the companies were from the database of the so-called QuiQuake system (Quick estimation system for earthquake maps triggered by observation records) operated by the National Institute of Advanced Industrial Science and Technology (AIST). It is noted that the estimated data were obtained by taking account of seismic local site effects and the actually observed ones. The tsunami height data at each site of the company were obtained by interpolating the confirmed data compiled by the 2011 Tohoku Earthquake Tsunami Joint Survey Group (2013). A frequency-damage level distribution for each seismic intensity is well correlated with a binominal distribution where the only parameter characterizing the distribution is an average value of the damage levels in each seismic intensity. The averaged damage levels of all the data for respective seismic intensity scales are 0.016 for SIj 5 lower, 0.042 for SIj 5 upper, 0.067 for SIj 6 lower, 0.092 for SIj 6 upper, and 0.16 for SIj 7, where SIj stands for the Japanese seismic intensity scale. The data were sorted into several classified industries and fragility curve for each classified industry is found to have a different character from each other. The tsunami fragilities are also obtained as a function of the tsunami height in the same way. The averaged damage levels of all the data for respective tsunami height are 0.051 for less than 3m, 0.23 for 0.3-1 m, 0.27 for 1-2 m, 0.43 for 2-3 m, and 0.50 for higher than 3m, respectively. These fragility curves can be useful not only to estimate economic damages for future huge earthquakes, but also to rapidly assess the damage just after earthquakes.

NASA-Produced Maps Help Gauge Italy Earthquake Damage

NASA Image and Video Library

2016-10-05

A NASA-funded program provided valuable information for responders and groups supporting the recovery efforts for the Aug. 24, 2016, magnitude 6.2 earthquake that struck central Italy. The earthquake caused significant loss of life and property damage in the town of Amatrice. To assist in the disaster response efforts, scientists at NASA's Jet Propulsion Laboratory and Caltech, both in Pasadena, California, obtained and used radar imagery of the earthquake's hardest-hit region to discriminate areas of damage from that event. The views indicate the extent of damage caused by the earthquake and subsequent aftershocks in and around Amatrice, based on changes to the ground surface detected by radar. The color variations from yellow to red indicate increasingly more significant ground surface change. The damage maps were created from data obtained before and after the earthquake by satellites belonging to the Italian Space Agency (ASI) and the Japan Aerospace Exploration Agency (JAXA). The radar-derived damage maps compare well with a damage map produced by the European Commission Copernicus Emergency Management Service based upon visual inspection of high-resolution pre-earthquake aerial photographs and post-earthquake satellite optical imagery, and provide broader geographic coverage of the earthquake's impact in the region. The X-band COSMO-SkyMed (CSK) data were provided through a research collaboration with ASI and were acquired on July 3, August 20, and August 28, 2016. The L-band ALOS/PALSAR-2 data were provided by JAXA through its science research program and were acquired on September 9, 2015, January 27, 2016, and August 24, 2016. The radar data were processed by the Advanced Rapid Imaging and Analysis (ARIA) team at JPL and Caltech. ARIA is a NASA-funded project that is building an automated system for demonstrating the ability to rapidly and reliably provide GPS and satellite data to support the local, national and international hazard monitoring and response communities. Using space-based imagery of disasters, ARIA data products can provide rapid assessments of the geographic region impacted by a disaster, as well as detailed imaging of the locations where damage occurred. Radar can "see" through clouds day and night and measure centimeter-level ground movements. NASA is partnering with the Indian Space Research Organization (ISRO) to develop the NASA ISRO Synthetic Aperture Radar (NISAR) mission that will routinely provide systematic SAR observations of Earth's land and ice-covered surfaces at least twice every 12 days, enabling greater scientific understanding of the dynamic processes that drive the Earth system and natural hazards, as well as providing actionable support for disaster response and recovery. http://photojournal.jpl.nasa.gov/catalog/PIA21091

The evaluation of damage mechanism of unreinforced masonry buildings after Van (2011) and Elazig (2010) Earthquakes

NASA Astrophysics Data System (ADS)

Güney, D.; Aydin, E.; Öztürk, B.

2015-07-01

On March 8th, 2010 Karakocan-Elazig earthquake of magnitude 6.0 occurred at a region where masonry and adobe construction is very common. Karakocan-Elazig is located in a high seismicity region on Eastern Anatolian Fault System (EAFS). Due to the earthquake, 42 people were killed and 14’113 buildings were damaged. Another city, Van located at South east of Turkey is hit by earthquakes with M = 7.2 occurred on October 23rd, 2011 at 13:41 (local time), whose epicenter was about 16 km north of Van (Tabanli village) and M = 5.6 on November 9th, 2011 with an epicenter near the town of Edremit, south of Van and caused the loss of life and heavy damages. Both earthquakes killed 644 people and 2608 people were injured. Approximately 10’000 buildings were seriously damaged. There are many traditional types of structures existing in the region hit by earthquakes (both Van and Elazig). These buildings were built as adobe, unreinforced masonry or mixed type. These types of buildings are very common in rural areas (especially south and east) of Turkey because of easy workmanship and cheap construction cost. Many of those traditional type structures experienced serious damages. The use of masonry is very common in some of the world's most hazard-prone regions, such as in Latin America, Africa, the Indian subcontinent and other parts of Asia, the Middle East, and southern Europe. Based on damage and failure mechanism of those buildings, the parameters affecting the seismic performance of those traditional buildings are analyzed in this paper. The foundation type, soil conditions, production method of the masonry blocks, construction method, the geometry of the masonry walls, workmanship quality, existence of wooden beams, type of roof, mortar between adobe blocks are studied in order to understand the reason of damage for these types of buildings.

Spatial variability of "Did You Feel It?" intensity data: insights into sampling biases in historical earthquake intensity distributions

USGS Publications Warehouse

Hough, Susan E.

2013-01-01

Recent parallel development of improved quantitative methods to analyze intensity distributions for historical earthquakes and of web‐based systems for collecting intensity data for modern earthquakes provides an opportunity to reconsider not only important individual historical earthquakes but also the overall characterization of intensity distributions for historical events. The focus of this study is a comparison between intensity distributions of historical earthquakes with those from modern earthquakes for which intensities have been determined by the U.S. Geological Survey “Did You Feel It?” (DYFI) website (see Data and Resources). As an example of a historical earthquake, I focus initially on the 1843 Marked Tree, Arkansas, event. Its magnitude has been previously estimated as 6.0–6.2. I first reevaluate the macroseismic effects of this earthquake, assigning intensities using a traditional approach, and estimate a preferred magnitude of 5.4. Modified Mercalli intensity (MMI) values for the Marked Tree earthquake are higher, on average, than those from the 2011 >Mw 5.8 Mineral, Virginia, earthquake for distances ≤500  km but comparable or lower on average at larger distances, with a smaller overall felt extent. Intensity distributions for other moderate historical earthquakes reveal similar discrepancies; the discrepancy is also even more pronounced using earlier published intensities for the 1843 earthquake. I discuss several hypotheses to explain the discrepancies, including the possibility that intensity values associated with historical earthquakes are commonly inflated due to reporting/sampling biases. A detailed consideration of the DYFI intensity distribution for the Mineral earthquake illustrates how reporting and sampling biases can account for historical earthquake intensity biases as high as two intensity units and for the qualitative difference in intensity distance decays for modern versus historical events. Thus, intensity maps for historical earthquakes tend to imply more widespread damage patterns than are revealed by intensity distributions of modern earthquakes of comparable magnitude. However, intensity accounts of historical earthquakes often include fragmentary accounts suggesting long‐period shaking effects that will likely not be captured fully in historical intensity distributions.

Studies of images of short-lived events using ERTS data. [forest fires, oil spills, vegetation damage, volcanoes, storm ridges, earthquakes, and floods

NASA Technical Reports Server (NTRS)

Deutschman, W. A. (Principal Investigator)

1973-01-01

The author has identified the following significant results. Detection of short-lived events has continued. Forest fires, oil spills, vegetation damage, volcanoes, storm ridges, earthquakes, and floods have been detected and analyzed.

A new method to assess damage to RCMRFs from period elongation and Park-Ang damage index using IDA

NASA Astrophysics Data System (ADS)

Aghagholizadeh, Mehrdad; Massumi, Ali

2016-09-01

Despite a significant progress in loading and design codes of seismic resistant structures and technology improvements in building structures, the field of civil engineering is still facing critical challenges. An example of those challenges is the assessment of the state of damage that has been imposed to a structure after earthquakes of different intensities. To determine the operability of a structure and its resistance to probable future earthquakes, quick assessment of damages and determining the operability of a structure after an earthquake are crucial. Present methods to calculate damage to structures are time consuming and do not accurately provide the rate of damage. Damage estimation is important task in the fields of structural health monitoring and decision-making. This study examines the relationship between period elongation and the Park-Ang damage index. A dynamic non-linear analysis is employed with IDARC program to calculate the amount of damage and period of the current state. This new method is shown to be a quick and accurate technique for damage assessment. It is easy to calculate the period of an existing structure and changes in the period which reflects changes in the stiffness matrix.

Structural damages of L'Aquila (Italy) earthquake

NASA Astrophysics Data System (ADS)

Kaplan, H.; Bilgin, H.; Yilmaz, S.; Binici, H.; Öztas, A.

2010-03-01

On 6 April 2009 an earthquake of magnitude 6.3 occurred in L'Aquila city, Italy. In the city center and surrounding villages many masonry and reinforced concrete (RC) buildings were heavily damaged or collapsed. After the earthquake, the inspection carried out in the region provided relevant results concerning the quality of the materials, method of construction and the performance of the structures. The region was initially inhabited in the 13th century and has many historic structures. The main structural materials are unreinforced masonry (URM) composed of rubble stone, brick, and hollow clay tile. Masonry units suffered the worst damage. Wood flooring systems and corrugated steel roofs are common in URM buildings. Moreover, unconfined gable walls, excessive wall thicknesses without connection with each other are among the most common deficiencies of poorly constructed masonry structures. These walls caused an increase in earthquake loads. The quality of the materials and the construction were not in accordance with the standards. On the other hand, several modern, non-ductile concrete frame buildings have collapsed. Poor concrete quality and poor reinforcement detailing caused damage in reinforced concrete structures. Furthermore, many structural deficiencies such as non-ductile detailing, strong beams-weak columns and were commonly observed. In this paper, reasons why the buildings were damaged in the 6 April 2009 earthquake in L'Aquila, Italy are given. Some suggestions are made to prevent such disasters in the future.

Impact of average household income and damage exposure on post-earthquake distress and functioning: A community study following the February 2011 Christchurch earthquake.

PubMed

Dorahy, Martin J; Rowlands, Amy; Renouf, Charlotte; Hanna, Donncha; Britt, Eileen; Carter, Janet D

2015-08-01

Post-traumatic stress, depression and anxiety symptoms are common outcomes following earthquakes, and may persist for months and years. This study systematically examined the impact of neighbourhood damage exposure and average household income on psychological distress and functioning in 600 residents of Christchurch, New Zealand, 4-6 months after the fatal February, 2011 earthquake. Participants were from highly affected and relatively unaffected suburbs in low, medium and high average household income areas. The assessment battery included the Acute Stress Disorder Scale, the depression module of the Patient Health Questionnaire (PHQ-9), and the Generalized Anxiety Disorder Scale (GAD-7), along with single item measures of substance use, earthquake damage and impact, and disruptions in daily life and relationship functioning. Controlling for age, gender and social isolation, participants from low income areas were more likely to meet diagnostic cut-offs for depression and anxiety, and have more severe anxiety symptoms. Higher probabilities of acute stress, depression and anxiety diagnoses were evident in affected versus unaffected areas, and those in affected areas had more severe acute stress, depression and anxiety symptoms. An interaction between income and earthquake effect was found for depression, with those from the low and medium income affected suburbs more depressed. Those from low income areas were more likely, post-earthquake, to start psychiatric medication and increase smoking. There was a uniform increase in alcohol use across participants. Those from the low income affected suburb had greater general and relationship disruption post-quake. Average household income and damage exposure made unique contributions to earthquake-related distress and dysfunction. © 2014 The British Psychological Society.

ELER software - a new tool for urban earthquake loss assessment

NASA Astrophysics Data System (ADS)

Hancilar, U.; Tuzun, C.; Yenidogan, C.; Erdik, M.

2010-12-01

Rapid loss estimation after potentially damaging earthquakes is critical for effective emergency response and public information. A methodology and software package, ELER-Earthquake Loss Estimation Routine, for rapid estimation of earthquake shaking and losses throughout the Euro-Mediterranean region was developed under the Joint Research Activity-3 (JRA3) of the EC FP6 Project entitled "Network of Research Infrastructures for European Seismology-NERIES". Recently, a new version (v2.0) of ELER software has been released. The multi-level methodology developed is capable of incorporating regional variability and uncertainty originating from ground motion predictions, fault finiteness, site modifications, inventory of physical and social elements subjected to earthquake hazard and the associated vulnerability relationships. Although primarily intended for quasi real-time estimation of earthquake shaking and losses, the routine is also equally capable of incorporating scenario-based earthquake loss assessments. This paper introduces the urban earthquake loss assessment module (Level 2) of the ELER software which makes use of the most detailed inventory databases of physical and social elements at risk in combination with the analytical vulnerability relationships and building damage-related casualty vulnerability models for the estimation of building damage and casualty distributions, respectively. Spectral capacity-based loss assessment methodology and its vital components are presented. The analysis methods of the Level 2 module, i.e. Capacity Spectrum Method (ATC-40, 1996), Modified Acceleration-Displacement Response Spectrum Method (FEMA 440, 2005), Reduction Factor Method (Fajfar, 2000) and Coefficient Method (ASCE 41-06, 2006), are applied to the selected building types for validation and verification purposes. The damage estimates are compared to the results obtained from the other studies available in the literature, i.e. SELENA v4.0 (Molina et al., 2008) and ATC-55 (Yang, 2005). An urban loss assessment exercise for a scenario earthquake for the city of Istanbul is conducted and physical and social losses are presented. Damage to the urban environment is compared to the results obtained from similar software, i.e. KOERILoss (KOERI, 2002) and DBELA (Crowley et al., 2004). The European rapid loss estimation tool is expected to help enable effective emergency response, on both local and global level, as well as public information.

Breaks in Pavement and Pipes as Indicators of Range-Front Faulting Resulting from the 1989 Loma Prieta Earthquake near the Southwest Margin of the Santa Clara Valley, California

USGS Publications Warehouse

Schmidt, Kevin M.; Ellen, Stephen D.; Haugerud, Ralph A.; Peterson, David M.; Phelps, Geoffery A.

1995-01-01

Damage to pavement and near-surface utility pipes, caused by the October 17, 1989, Loma Prieta earthquake, provide indicators for ground deformation in a 663 km2 area near the southwest margin of the Santa Clara Valley, California. The spatial distribution of 1284 sites of such damage documents the extent and distribution of detectable ground deformation. Damage was concentrated in four zones, three of which are near previously mapped faults. The zone through Los Gatos showed the highest concentration of damage, as well as evidence for pre- and post-earthquake deformation. Damage along the foot of the Santa Cruz Mountains reflected shortening that is consistent with movement along reverse faults in the region and with the hypothesis that tectonic strain is distributed widely across numerous faults in the California Coast Ranges.

Early Earthquakes of the Americas

NASA Astrophysics Data System (ADS)

Ni, James

2004-11-01

Robert Kovach's second book looks at the interplay of earthquake and volcanic events, archeology, and history in the Americas. Throughout history, major earthquakes have caused the deaths of millions of people and have damaged countless cities. Earthquakes undoubtedly damaged prehistoric cities in the Americas, and evidence of these events could be preserved in archeological records. Kovach asks, Did indigenous native cultures-Indians of the Pacific Northwest, Aztecs, Mayas, and Incas-document their natural history? Some events have been explicitly documented, for example, in Mayan codices, but many may have been recorded as myth and legend. Kovach's discussions of how early cultures dealt with fearful events such as earthquakes and volcanic eruptions are colorful, informative, and entertaining, and include, for example, a depiction of how the Maya would talk to maize plants in their fields during earthquakes to reassure them.

The Loma Prieta, California, Earthquake of October 17, 1989: Performance of the Built Environment

USGS Publications Warehouse

Coordinated by Holzer, Thomas L.

1998-01-01

Professional Paper 1552 focuses on the response of buildings, lifelines, highway systems, and earth structures to the earthquake. Losses to these systems totaled approximated $5.9 billion. The earthquake displaced many residents from their homes and severely disrupted transportation systems. Some significant findings were: * Approximately 16,000 housing units were uninhabitable after the earthquake including 13,000 in the San Francisco Bay region. Another 30,000-35,000 units were moderately damaged in the earthquake. Renters and low-income residents were particularly hard hit. * Failure of highway systems was the single largest cause of loss of life during the earthquake. Forty-two of the 63 earthquake fatalities died when the Cypress Viaduct in Oakland collapsed. The cost to repair and replace highways damaged by the earthquake was $2 billion, about half of which was to replace the Cypress Viaduct. * Major bridge failures were the result of antiquated designs and inadequate anticipation of seismic loading. * Twenty one kilometers (13 mi) of gas-distribution lines had to be replaced in several communities and more than 1,200 leaks and breaks in water mains and service connections had to be excavated and repaired. At least 5 electrical substations were badly damaged, overwhelming the designed redundancy of the electrical system. * Instruments in 28 buildings recorded their response to earthquake shaking that provided opportunities to understand how different types of buildings responded, the importance of site amplification, and how buildings interact with their foundation when shaken (soil structure interaction).

Sustained water-level changes caused by damage and compaction induced by teleseismic earthquakes

NASA Astrophysics Data System (ADS)

Shalev, Eyal; Kurzon, Ittai; Doan, Mai-Linh; Lyakhovsky, Vladimir

2016-07-01

Sustained water-level increase and decrease induced by distant earthquakes were observed in two wells, Gomè 1 and Meizar 1 in Israel. The Gomè 1 well is located within a damage zone of a major fault zone, and Meizar 1 is relatively far from a fault. The monitored pressure change in both wells shows significant water-level oscillations and sustained water-level changes in response to the passage of the seismic waves. The sustained water-level changes include short-term (minutes) undrained behavior and longer-period (hours and days) drained behavior associated with groundwater flow. We model the short-term undrained response of water pressure oscillations and sustained change to the distant 2013 Mw 7.7 Balochistan earthquake by nonlinear elastic behavior of damaged rocks, accounting for small wave-induced compaction and damage accumulation. We suggest that the rocks are close to failure in both locations and strain oscillations produced by the passing seismic waves periodically push the rock above the yield cap, creating compaction when volumetric strain increases and damage when shear strain increases. Compaction increases pore pressure, whereas damage accumulation decreases pore pressure by fracture dilation. The dominant process depends on the properties of the rock. For highly damaged rocks, dilatancy is dominant and a sustained pressure decrease is expected. For low-damage rocks, compaction is the dominant process creating sustained water-level increase. We calculate damage and porosity changes associated to the Balochistan earthquake in both wells and quantify damage accumulation and compaction during the passage of the seismic waves.

Application of laser scanning technique in earthquake protection of Istanbul's historical heritage buildings

NASA Astrophysics Data System (ADS)

Çaktı, Eser; Ercan, Tülay; Dar, Emrullah

2017-04-01

Istanbul's vast historical and cultural heritage is under constant threat of earthquakes. Historical records report repeated damages to the city's landmark buildings. Our efforts towards earthquake protection of several buildings in Istanbul involve earthquake monitoring via structural health monitoring systems, linear and non-linear structural modelling and analysis in search of past and future earthquake performance, shake-table testing of scaled models and non-destructive testing. More recently we have been using laser technology in monitoring structural deformations and damage in five monumental buildings which are Hagia Sophia Museum and Fatih, Sultanahmet, Süleymaniye and Mihrimah Sultan Mosques. This presentation is about these efforts with special emphasis on the use of laser scanning in monitoring of edifices.

RICHTER: A Smartphone Application for Rapid Collection of Geo-Tagged Pictures of Earthquake Damage

NASA Astrophysics Data System (ADS)

Skinnemoen, H.; Bossu, R.; Furuheim, K.; Bjorgo, E.

2010-12-01

RICHTER (Rapid geo-Images for Collaborative Help Targeting Earthquake Response) is a smartphone version of a professional application developed to provide high quality geo-tagged image communication over challenging network links, such as satellites and poor mobile links. Developed for Android mobile phones, it allows eyewitnesses to share their pictures of earthquake damage easily and without cost with the Euro-Mediterranean Seismological Centre (EMSC). The goal is to engage citizens in the collection of the most up-to-date visual information on local damage for improved rapid impact assessment. RICHTER integrates the innovative and award winning ASIGN protocol initially developed for satellite communication between cameras / computers / satcom terminals and servers at HQ. ASIGN is a robust and optimal image and video communication management solution for bandwidth-limited communication networks which was developed for use particularly in emergency and disaster situations. Contrary to a simple Multimedia Messaging System (MMS), RICHTER allows access to high definition images with embedded location information. Location is automatically assigned from either the internal GPS, derived from the mobile network (triangulation) or the current Wi-Fi domain, in that order, as this corresponds to the expected positioning accuracy. Pictures are compressed to 20-30KB of data typically for fast transfer and to avoid network overload. Full size images can be requested by the EMSC either fully automatically, or on a case-by-case basis, depending on the user preferences. ASIGN was initially developed in coordination with INMARSAT and the European Space Agency. It was used by the Rapid Mapping Unit of the United Nations notably for the damage assessment of the January 12, 2010 Haiti earthquake where more than 700 photos were collected. RICHTER will be freely distributed on the EMSC website to eyewitnesses in the event of significantly damaging earthquakes. The EMSC is the second most popular rapid earthquake information website after the USGS. Eyewitnesses of widely felt or damaging earthquakes usually arrive at the EMSC website within a couple of minutes of the event’s occurrence, making it an ideal site for rapid and targeted dissemination. RICHTER is the latest development in a series of internet applications designed to harness the collective power of citizens to provide rapid earthquake damage analysis reports. This strategy is called “Citizen Seismology,” and includes online macroseismic questionnaires available in 32 languages, real time analysis of EMSC website traffic to map felt and damaged areas from localized increases - or significant absence - of visitors after an earthquake occurrence, collection of pictures, mobile-phone targeted macroseismic questionnaires in which damage-representative thumbnail images replace textual questionnaires, as well as a citizen-operated network of embedded laptop motion sensors. Future developments for RICHTER under consideration include the collection of video and harnessing the embedded motion sensors to capture seismic activity.

Study on vulnerability matrices of masonry buildings of mainland China

NASA Astrophysics Data System (ADS)

Sun, Baitao; Zhang, Guixin

2018-04-01

The degree and distribution of damage to buildings subjected to earthquakes is a concern of the Chinese Government and the public. Seismic damage data indicates that seismic capacities of different types of building structures in various regions throughout mainland China are different. Furthermore, the seismic capacities of the same type of structure in different regions may vary. The contributions of this research are summarized as follows: 1) Vulnerability matrices and earthquake damage matrices of masonry structures in mainland China were chosen as research samples. The aim was to analyze the differences in seismic capacities of sample matrices and to present general rules for categorizing seismic resistance. 2) Curves relating the percentage of damaged masonry structures with different seismic resistances subjected to seismic demand in different regions of seismic intensity (VI to X) have been developed. 3) A method has been proposed to build vulnerability matrices of masonry structures. The damage ratio for masonry structures under high-intensity events such as the Ms 6.1 Panzhihua earthquake in Sichuan province on 30 August 2008, was calculated to verify the applicability of this method. This research offers a significant theoretical basis for predicting seismic damage and direct loss assessment of groups of buildings, as well as for earthquake disaster insurance.

Characteristics of strong motions and damage implications of M S6.5 Ludian earthquake on August 3, 2014

NASA Astrophysics Data System (ADS)

Xu, Peibin; Wen, Ruizhi; Wang, Hongwei; Ji, Kun; Ren, Yefei

2015-02-01

The Ludian County of Yunnan Province in southwestern China was struck by an M S6.5 earthquake on August 3, 2014, which was another destructive event following the M S8.0 Wenchuan earthquake in 2008, M S7.1 Yushu earthquake in 2010, and M S7.0 Lushan earthquake in 2013. National Strong-Motion Observation Network System of China collected 74 strong motion recordings, which the maximum peak ground acceleration recorded by the 053LLT station in Longtoushan Town was 949 cm/s2 in E-W component. The observed PGAs and spectral ordinates were compared with ground-motion prediction equation in China and the NGA-West2 developed by Pacific Earthquake Engineering Researcher Center. This earthquake is considered as the first case for testing applicability of NGA-West2 in China. Results indicate that the observed PGAs and the 5 % damped pseudo-response spectral accelerations are significantly lower than the predicted ones. The field survey around some typical strong motion stations verified that the earthquake damage was consistent with the official isoseismal by China Earthquake Administration.

Nonstructural damages of reinforced concrete buildings due to 2015 Ranau earthquake

NASA Astrophysics Data System (ADS)

Adiyanto, Mohd Irwan; Majid, Taksiah A.; Nazri, Fadzli Mohamed

2017-07-01

On 15th June 2016 a moderate earthquake with magnitude Mw5.9 was occurred in Sabah, Malaysia. Specifically, the epicentre was located at 16 km northwest of Ranau. Less than two days after the first event, a reconnaissance mission took action to investigate the damages on buildings. Since the reinforced concrete buildings in Ranau were designed based on gravity and wind load only, a lot of minor to severe damages was occurred. This paper presents the damages on the nonstructural elements of reinforced concrete buildings due to Ranau earthquake. The assessment was conducted via in-situ field investigation covering the visual observation, taking photo, and interview with local resident. Based on in-situ field investigation, there was a lot of damages occurred on the nonstructural elements like the brick walls. Such damages cannot be neglected since it can cause injury and fatality to the victims. Therefore, it can be concluded that the installation of nonstructural elements should be reviewed for the sake of safety.

Integrating Machine Learning into a Crowdsourced Model for Earthquake-Induced Damage Assessment

NASA Technical Reports Server (NTRS)

Rebbapragada, Umaa; Oommen, Thomas

2011-01-01

On January 12th, 2010, a catastrophic 7.0M earthquake devastated the country of Haiti. In the aftermath of an earthquake, it is important to rapidly assess damaged areas in order to mobilize the appropriate resources. The Haiti damage assessment effort introduced a promising model that uses crowdsourcing to map damaged areas in freely available remotely-sensed data. This paper proposes the application of machine learning methods to improve this model. Specifically, we apply work on learning from multiple, imperfect experts to the assessment of volunteer reliability, and propose the use of image segmentation to automate the detection of damaged areas. We wrap both tasks in an active learning framework in order to shift volunteer effort from mapping a full catalog of images to the generation of high-quality training data. We hypothesize that the integration of machine learning into this model improves its reliability, maintains the speed of damage assessment, and allows the model to scale to higher data volumes.

Foreshock patterns preceding large earthquakes in the subduction zone of Chile

NASA Astrophysics Data System (ADS)

Minadakis, George; Papadopoulos, Gerassimos A.

2016-04-01

Some of the largest earthquakes in the globe occur in the subduction zone of Chile. Therefore, it is of particular interest to investigate foreshock patterns preceding such earthquakes. Foreshocks in Chile were recognized as early as 1960. In fact, the giant (Mw9.5) earthquake of 22 May 1960, which was the largest ever instrumentally recorded, was preceded by 45 foreshocks in a time period of 33h before the mainshock, while 250 aftershocks were recorded in a 33h time period after the mainshock. Four foreshocks were bigger than magnitude 7.0, including a magnitude 7.9 on May 21 that caused severe damage in the Concepcion area. More recently, Brodsky and Lay (2014) and Bedford et al. (2015) reported on foreshock activity before the 1 April 2014 large earthquake (Mw8.2). However, 3-D foreshock patterns in space, time and size were not studied in depth so far. Since such studies require for good seismic catalogues to be available, we have investigated 3-D foreshock patterns only before the recent, very large mainshocks occurring on 27 February 2010 (Mw 8.8), 1 April 2014 (Mw8.2) and 16 September 2015 (Mw8.4). Although our analysis does not depend on a priori definition of short-term foreshocks, our interest focuses in the short-term time frame, that is in the last 5-6 months before the mainshock. The analysis of the 2014 event showed an excellent foreshock sequence consisting by an early-weak foreshock stage lasting for about 1.8 months and by a main-strong precursory foreshock stage that was evolved in the last 18 days before the mainshock. During the strong foreshock period the seismicity concentrated around the mainshock epicenter in a critical area of about 65 km mainly along the trench domain to the south of the mainshock epicenter. At the same time, the activity rate increased dramatically, the b-value dropped and the mean magnitude increased significantly, while the level of seismic energy released also increased. In view of these highly significant seismicity changes we used the 1 April 2014 large earthquake as a reference event when examining the 2015 and 2010 large Chilean earthquakes. This consideration is also justified by that the 3-D patterns revealed before the 2014 earthquake are quite similar to the ones that preceded the M = 6.3 L'Aquila (Italy) mainshock of 6 April 2009. The 2015 large event was preceded only by a weak foreshock sequence while no statistically significant foreshock activity was detected before the 2010 large mainshock. It is not clear so far if these different results are due to geophysical factors or to the fact that the catalogue completeness is much better in the area of the 2014 event than in the areas of 2010 and 2015 events. This is a contribution of the research project EARTHWARN, funded by the Institute of Geodynamics, National Observatory of Athens, Greece.

Resilience of aging populations after devastating earthquake event and its determinants - A case study of the Chi-Chi earthquake in Taiwan

NASA Astrophysics Data System (ADS)

Hung, Chih-Hsuan; Hung, Hung-Chih

2016-04-01

1.Background Major portions of urban areas in Asia are highly exposed and vulnerable to devastating earthquakes. Many studies identify ways to reduce earthquake risk by concentrating more on building resilience for the particularly vulnerable populations. By 2020, as the United Nations' warning, many Asian countries would become 'super-aged societies', such as Taiwan. However, local authorities rarely use resilience approach to frame earthquake disaster risk management and land use strategies. The empirically-based research about the resilience of aging populations has also received relatively little attention. Thus, a challenge arisen for decision-makers is how to enhance resilience of aging populations within the context of risk reduction. This study aims to improve the understanding of the resilience of aging populations and its changes over time in the aftermath of a destructive earthquake at the local level. A novel methodology is proposed to assess the resilience of aging populations and to characterize their changes of spatial distribution patterns, as well as to examine their determinants. 2.Methods and data An indicator-based assessment framework is constructed with the goal of identifying composite indicators (including before, during and after a disaster) that could serve as proxies for attributes of the resilience of aging populations. Using the recovery process of the Chi-Chi earthquake struck central Taiwan in 1999 as a case study, we applied a method combined a geographical information system (GIS)-based spatial statistics technique and cluster analysis to test the extent of which the resilience of aging populations is spatially autocorrelated throughout the central Taiwan, and to explain why clustering of resilient areas occurs in specific locations. Furthermore, to scrutinize the affecting factors of resilience, we develop an aging population resilience model (APRM) based on existing resilience theory. Using the APRM, we applied a multivariate regression analysis to identify and examine how various factors connect to the resilience of aging populations. To illustrate the proposed methodology, the study collected data on the resilience attributes, the disaster impacts and damages due to the Chi-Chi earthquake. The data were offered by the National Science and Technology Center for Disaster Reduction, Taiwan, as well as collected from the National Land Use Investigation, official census statistics and questionnaire surveys. 3.Results Integrating cluster analysis with GIS-based spatial statistical analysis, the resilience of aging populations were divided into five clusters of distribution patterns over the 10 years after the Chi-Chi earthquake. It shows that both population and elderly distributions were highly heterogeneous and spatial correlated across the study areas. We also demonstrated the 'hot spots' areas of the highly concentrated aging population across central Taiwan. Results of regression analysis disclosed the major factors that caused low resilience and changes of aging population distributions over time. These factors included the levels of seismic damage, infrastructure investments, as well as the land-use and socioeconomic attributes associated with the disaster areas. Finally, our findings provide stakeholders and policy-makers with better adaptive options to design and synthesize appropriate patchworks of planning measures for different types of resilience areas to reduce earthquake disaster risk.

Knowledge base about earthquakes as a tool to minimize strong events consequences

NASA Astrophysics Data System (ADS)

Frolova, Nina; Bonnin, Jean; Larionov, Valery; Ugarov, Alexander; Kijko, Andrzej

2017-04-01

The paper describes the structure and content of the knowledge base on physical and socio-economical consequences of damaging earthquakes, which may be used for calibration of near real-time loss assessment systems based on simulation models for shaking intensity, damage to buildings and casualties estimates. Such calibration allows to compensate some factors which influence on reliability of expected damage and loss assessment in "emergency" mode. The knowledge base contains the description of past earthquakes' consequences for the area under study. It also includes the current distribution of built environment and population at the time of event occurrence. Computer simulation of the recorded in knowledge base events allow to determine the sets of regional calibration coefficients, including rating of seismological surveys, peculiarities of shaking intensity attenuation and changes in building stock and population distribution, in order to provide minimum error of damaging earthquakes loss estimations in "emergency" mode. References 1. Larionov, V., Frolova, N: Peculiarities of seismic vulnerability estimations. In: Natural Hazards in Russia, volume 6: Natural Risks Assessment and Management, Publishing House "Kruk", Moscow, 120-131, 2003. 2. Frolova, N., Larionov, V., Bonnin, J.: Data Bases Used In Worlwide Systems For Earthquake Loss Estimation In Emergency Mode: Wenchuan Earthquake. In Proc. TIEMS2010 Conference, Beijing, China, 2010. 3. Frolova N. I., Larionov V. I., Bonnin J., Sushchev S. P., Ugarov A. N., Kozlov M. A. Loss Caused by Earthquakes: Rapid Estimates. Natural Hazards Journal of the International Society for the Prevention and Mitigation of Natural Hazards, vol.84, ISSN 0921-030, Nat Hazards DOI 10.1007/s11069-016-2653

Breaking new ground for remote sensing in support of disaster relief efforts: Detecting and pinpointing earthquake damage in near real-time (El Salvador, January 2001)

NASA Astrophysics Data System (ADS)

Nezry, Edmond; Romeijn, Paul P.; Sarti, Francesco; Inglada, Jordi; Zagolski, Francis; Yakam-Simen, Francis

2002-01-01

On January 13th 2001, a very strong earthquake struck El-Salvador, causing almost 1000 deaths and huge destruction, leaving more than one million people homeless. As support to the rescue teams, a project was initiated to provide up-to date maps and to identify damages to housing and infrastructures, covering the whole country. Based on the analysis of SPOT Panchromatic satellite imagery, updated maps were delivered to the rescue teams within 72 hours after the earthquake. In addition, during the 10 days following the earthquake, high resolution mapping of the damages was carried out in cooperation and coordination with rescue teams and relief organizations. Some areas of particular interest were even processed and damage maps delivered through the Internet, three hours after the request. For the first time in the history of spaceborne Earth observation, identification and evaluation of the damages were delivered on-site, in real-time (during the interventions), to local authorities, rescue teams and humanitarian organizations. In this operation, operating 24 hours a day and technical ability were the keys for success and contributed to saving lives.

Unbonded Prestressed Columns for Earthquake Resistance

DOT National Transportation Integrated Search

2012-05-01

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

Observations on water system and pipeline performance in the Limon area of Costa Rica due to the April 22, 1991 earthquake. Technical report

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

O'Rourke, M.J.; Ballantyne, D.

The document focuses on earthquake damage to water and oil pipelines, water supply, and water treatment following the 22 April 1991 Costa Rica Earthquake. The moment magnitude 7.5 earthquake occurred approximately 40 km south-southwest of Limon, and resulted in a coseismic uplift of up to 1.5 meters along Costa Rica's east coast. The report also provides an overview of the engineering aspects of the event and recovery activities. Turbidity in the watershed which provides Limon's primary water supply increased to as high as 2.4 percent solids, making it extremely difficult to treat. In addition, the water treatment plant was damagedmore » by the earthquake. Cast iron, ductile iron and reinforced concrete cylinder pipe water transmission lines were damaged by both wave propagation and permanent ground deformation. Water distribution piping, also including PVC and galvanized iron, was similarly impacted. Documentation and evaluation of that damage is described, and compared with empirical estimates from previous earthquakes. Twin 150 mm (6 in), 100 km long, oil transmission lines suffered only a single failure from wrinkling. A description of the pipelines and the failure is provided.« less

Building vulnerability and human loss assessment in different earthquake intensity and time: a case study of the University of the Philippines, Los Baños (UPLB) Campus

NASA Astrophysics Data System (ADS)

Rusydy, I.; Faustino-Eslava, D. V.; Muksin, U.; Gallardo-Zafra, R.; Aguirre, J. J. C.; Bantayan, N. C.; Alam, L.; Dakey, S.

2017-02-01

Study on seismic hazard, building vulnerability and human loss assessment become substantial for building education institutions since the building are used by a lot of students, lecturers, researchers, and guests. The University of the Philippines, Los Banos (UPLB) located in an earthquake prone area. The earthquake could cause structural damage and injury of the UPLB community. We have conducted earthquake assessment in different magnitude and time to predict the posibility of ground shaking, building vulnerability and estimated the number of casualty of the UPLB community. The data preparation in this study includes the earthquake scenario modeling using Intensity Prediction Equations (IPEs) for shallow crustal shaking attenuation to produce intensity map of bedrock and surface. Earthquake model was generated from the segment IV and the segment X of the Valley Fault System (VFS). Building vulnerability of different type of building was calculated using fragility curve of the Philippines building. The population data for each building in various occupancy time, damage ratio, and injury ratio data were used to compute the number of casualties. The result reveals that earthquake model from the segment IV and the segment X of the VFS could generate earthquake intensity between 7.6 - 8.1 MMI in the UPLB campus. The 7.7 Mw earthquake (scenario I) from the segment IV could cause 32% - 51% damage of building and 6.5 Mw earthquake (scenario II) occurring in the segment X could cause 18% - 39% structural damage of UPLB buildings. If the earthquake occurs at 2 PM (day-time), it could injure 10.2% - 18.8% for the scenario I and could injure 7.2% - 15.6% of UPLB population in scenario II. The 5 Pm event, predicted will injure 5.1%-9.4% in the scenario I, and 3.6%-7.8% in scenario II. A nighttime event (2 Am) cause injury to students and guests who stay in dormitories. The earthquake is predicted to injure 13 - 66 students and guests in the scenario I and 9 - 47 people in the scenario II. To reduce the number of injuries, the authority of UPLB have to carry out the buildings restoration, set up earthquake early warning system in all dormitories, and evacuation sign board.

Children's Ideas about Earthquakes

ERIC Educational Resources Information Center

Simsek, Canan Lacin

2007-01-01

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

Turkish Children's Ideas about Earthquakes

ERIC Educational Resources Information Center

Simsek, Canan Lacin

2007-01-01

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

Building Damage Assessment after Earthquake Using Post-Event LiDAR Data

NASA Astrophysics Data System (ADS)

Rastiveis, H.; Eslamizade, F.; Hosseini-Zirdoo, E.

2015-12-01

After an earthquake, damage assessment plays an important role in leading rescue team to help people and decrease the number of mortality. Damage map is a map that demonstrates collapsed buildings with their degree of damage. With this map, finding destructive buildings can be quickly possible. In this paper, we propose an algorithm for automatic damage map generation after an earthquake using post-event LiDAR Data and pre-event vector map. The framework of the proposed approach has four main steps. To find the location of all buildings on LiDAR data, in the first step, LiDAR data and vector map are registered by using a few number of ground control points. Then, building layer, selected from vector map, are mapped on the LiDAR data and all pixels which belong to the buildings are extracted. After that, through a powerful classifier all the extracted pixels are classified into three classes of "debris", "intact building" and "unclassified". Since textural information make better difference between "debris" and "intact building" classes, different textural features are applied during the classification. After that, damage degree for each candidate building is estimated based on the relation between the numbers of pixels labelled as "debris" class to the whole building area. Calculating the damage degree for each candidate building, finally, building damage map is generated. To evaluate the ability proposed method in generating damage map, a data set from Port-au-Prince, Haiti's capital after the 2010 Haiti earthquake was used. In this case, after calculating of all buildings in the test area using the proposed method, the results were compared to the damage degree which estimated through visual interpretation of post-event satellite image. Obtained results were proved the reliability of the proposed method in damage map generation using LiDAR data.

Seismic velocities and geologic logs from boreholes at three downhole arrays in San Francisco, California

USGS Publications Warehouse

Gibbs, James F.; Fumal, Thomas E.; Borcherdt, Roger D.; Warrick, Richard E.; Liu, Hsi-Ping; Westerlund, Robert E.

1994-01-01

The Loma Prieta earthquake of October 17, 1989 (1704 PST), has reinforced observations made by Wood and others (1908) after the 1906 San Francisco earthquake, that poor ground conditions (soft soil) increase the likelihood of shaking damage to structures. Since 1908 many studies (for example Borcherdt, 1970, Borcherdt and Gibbs, 1976, Borcherdt and Glassmoyer, 1992) have shown that soft soils amplify seismic waves at frequencies that can be damaging to structures. Damage in the City of San Francisco from the Loma Prieta earthquake was concentrated in the Marina District, the Embarcadero, and the China Basin areas. Each of these areas, to some degree, is underlain by soft soil deposits. These concentrations of damage raise important questions regarding the amplification effects of such deposits at damaging levels of motion. Unfortunately, no strong-motion recordings were obtained in these areas during the Loma Prieta earthquake and only a limited number (< 10) have been obtained on other soft soil sites in the United States. Consequently, important questions exist regarding the response of such deposits during damaging earthquakes, especially questions regarding the nonlinear soil response. Towards developing a data set to address these important questions, borehole strong-motion arrays have been installed at three locations. These arrays consist of groups of wide-dynamic-range pore-pressure transducers and three-component accelerometers, the outputs of which are recorded digitally. The arrays are designed to provide an integrated set of data on ground shaking, liquifaction-induced ground failure, and structural response. This report describes the detailed geologic, seismic, and material-property determinations derived at each of these sites.

A classifying method analysis on the number of returns for given pulse of post-earthquake airborne LiDAR data

NASA Astrophysics Data System (ADS)

Wang, Jinxia; Dou, Aixia; Wang, Xiaoqing; Huang, Shusong; Yuan, Xiaoxiang

2016-11-01

Compared to remote sensing image, post-earthquake airborne Light Detection And Ranging (LiDAR) point cloud data contains a high-precision three-dimensional information on earthquake disaster which can improve the accuracy of the identification of destroy buildings. However after the earthquake, the damaged buildings showed so many different characteristics that we can't distinguish currently between trees and damaged buildings points by the most commonly used method of pre-processing. In this study, we analyse the number of returns for given pulse of trees and damaged buildings point cloud and explore methods to distinguish currently between trees and damaged buildings points. We propose a new method by searching for a certain number of neighbourhood space and calculate the ratio(R) of points whose number of returns for given pulse greater than 1 of the neighbourhood points to separate trees from buildings. In this study, we select some point clouds of typical undamaged building, collapsed building and tree as samples from airborne LiDAR point cloud data which got after 2010 earthquake in Haiti MW7.0 by the way of human-computer interaction. Testing to get the Rvalue to distinguish between trees and buildings and apply the R-value to test testing areas. The experiment results show that the proposed method in this study can distinguish between building (undamaged and damaged building) points and tree points effectively but be limited in area where buildings various, damaged complex and trees dense, so this method will be improved necessarily.

A media information analysis for implementing effective countermeasure against harmful rumor

NASA Astrophysics Data System (ADS)

Nagao, Mitsuyoshi; Suto, Kazuhiro; Ohuchi, Azuma

2010-04-01

When large scale earthquake occurred, the word of "harmful rumor" came to be frequently heard. The harmful rumor means an economic damage which is caused by the action that people regard actually safe foods or areas as dangerous and then abort consumption or sightseeing. In the case of harmful rumor caused by earthquake, especially, tourism industry receives massive economic damage. Currently, harmful rumor which gives substantial economic damage have become serious social issue which must be solved. In this paper, we propose a countermeasure method for harmful rumor on the basis of media trend in order to implement speedy recovery from harmful rumor. Here, we investigate the amount and content of information which is transmitted to the general public by the media when an earthquake occurred. In addition, the media information in three earthquakes is treated as instance. Finally, we discuss an effective countermeasure method for dispeling harmful rumor through these analysis results.

Cumulative co-seismic fault damage and feedbacks on earthquake rupture

NASA Astrophysics Data System (ADS)

Mitchell, T. M.; Aben, F. M.; Ostermeijer, G.; Rockwell, T. K.; Doan, M. L.

2017-12-01

The importance of the damage zone in the faulting and earthquake process is widely recognized, but our understanding of how damage zones are created, what their properties are, and how they feed back into the seismic cycle, is remarkably poorly known. Firstly, damaged rocks have reduced elastic moduli, cohesion and yield strength, which can cause attenuation and potentially non-linear wave propagation effects during ruptures. Secondly, damaged fault rocks are generally more permeable than intact rocks, and hence play a key role in the migration of fluids in and around fault zones over the seismic cycle. Finally, the dynamic generation of damage as the earthquake propagates can itself influence the dynamics of rupture propagation, by increasing the amount of energy dissipation, decreasing the rupture velocity, modifying the size of the earthquake, changing the efficiency of weakening mechanisms such as thermal pressurisation of pore fluids, and even generating seismic waves itself . All of these effects imply that a feedback exists between the damage imparted immediately after rupture propagation, at the early stages of fault slip, and the effects of that damage on subsequent ruptures dynamics. In recent years, much debate has been sparked by the identification of so-called `pulverized rocks' described on various crustal-scale faults, a type of intensely damaged fault rock which has undergone minimal shear strain, and the occurrence of which has been linked to damage induced by transient high strain-rate stress perturbations during earthquake rupture. Damage induced by such transient stresses, whether compressional or tensional, likely constitute heterogeneous modulations of the remote stresses that will impart significant changes on the strength, elastic and fluid flow properties of a fault zone immediately after rupture propagation, at the early stage of fault slip. In this contribution, we will demonstrate laboratory and field examples of two dynamic mechanisms that have been proposed for the generation of pulverized rocks; (i) compressive loading by high-frequency stress pulses due to the radiation of seismic waves and (ii) explosive dilation in tension in rocks containing pressurized pore fluids.

Preliminary investigation of some large landslides triggered by the 2008 Wenchuan earthquake, Sichuan Province, China

USGS Publications Warehouse

Wang, F.; Cheng, Q.; Highland, L.; Miyajima, M.; Wang, Hongfang; Yan, C.

2009-01-01

The M s 8.0 Wenchuan earthquake or "Great Sichuan Earthquake" occurred at 14:28 p.m. local time on 12 May 2008 in Sichuan Province, China. Damage by earthquake-induced landslides was an important part of the total earthquake damage. This report presents preliminary observations on the Hongyan Resort slide located southwest of the main epicenter, shallow mountain surface failures in Xuankou village of Yingxiu Town, the Jiufengchun slide near Longmenshan Town, the Hongsong Hydro-power Station slide near Hongbai Town, the Xiaojiaqiao slide in Chaping Town, two landslides in Beichuan County-town which destroyed a large part of the town, and the Donghekou and Shibangou slides in Qingchuan County which formed the second biggest landslide lake formed in this earthquake. The influences of seismic, topographic, geologic, and hydro-geologic conditions are discussed. ?? 2009 Springer-Verlag.

The 1964 Great Alaska Earthquake and tsunamis: a modern perspective and enduring legacies

USGS Publications Warehouse

Brocher, Thomas M.; Filson, John R.; Fuis, Gary S.; Haeussler, Peter J.; Holzer, Thomas L.; Plafker, George; Blair, J. Luke

2014-01-01

The magnitude 9.2 Great Alaska Earthquake that struck south-central Alaska at 5:36 p.m. on Friday, March 27, 1964, is the largest recorded earthquake in U.S. history and the second-largest earthquake recorded with modern instruments. The earthquake was felt throughout most of mainland Alaska, as far west as Dutch Harbor in the Aleutian Islands some 480 miles away, and at Seattle, Washington, more than 1,200 miles to the southeast of the fault rupture, where the Space Needle swayed perceptibly. The earthquake caused rivers, lakes, and other waterways to slosh as far away as the coasts of Texas and Louisiana. Water-level recorders in 47 states—the entire Nation except for Connecticut, Delaware, and Rhode Island— registered the earthquake. It was so large that it caused the entire Earth to ring like a bell: vibrations that were among the first of their kind ever recorded by modern instruments. The Great Alaska Earthquake spawned thousands of lesser aftershocks and hundreds of damaging landslides, submarine slumps, and other ground failures. Alaska’s largest city, Anchorage, located west of the fault rupture, sustained heavy property damage. Tsunamis produced by the earthquake resulted in deaths and damage as far away as Oregon and California. Altogether the earthquake and subsequent tsunamis caused 129 fatalities and an estimated $2.3 billion in property losses (in 2013 dollars). Most of the population of Alaska and its major transportation routes, ports, and infrastructure lie near the eastern segment of the Aleutian Trench that ruptured in the 1964 earthquake. Although the Great Alaska Earthquake was tragic because of the loss of life and property, it provided a wealth of data about subductionzone earthquakes and the hazards they pose. The leap in scientific understanding that followed the 1964 earthquake has led to major breakthroughs in earth science research worldwide over the past half century. This fact sheet commemorates Great Alaska Earthquake and examines the advances in knowledge and technology that have helped to improve earthquake preparation and response both in Alaska and around the world.

Seismicity and Seismic Hazard along the Western part of the Eurasia-Nubia plate boundary

NASA Astrophysics Data System (ADS)

Bezzeghoud, Mourad; Fontiela, João; Ferrão, Celia; Borges, José Fernando; Caldeira, Bento; Dib, Assia; Ousadou, Farida

2016-04-01

The seismic phenomenon is the most damaging natural hazard known in the Mediterranean area. The western part of the Eurasia-Nubia plate boundary extends from the Azores to the Mediterranean region. The oceanic part of the plate boundary is well delimited from the Azores Islands, along the Azores-Gibraltar fault to approximately 12°W (west of the Strait of Gibraltar). From 12°W to 3.5°E, including the Iberia-Nubia region and extending to the western part of Algeria, the boundary is more diffuse and forms a wider area of deformation. The boundary between the Iberia and Nubia plates is the most complex part of the margin. This region corresponds to the transition from an oceanic boundary to a continental boundary, where Iberia and Nubia collide. Although most earthquakes along this plate boundary are shallow and generally have magnitudes less than 5.5, there have been several high-magnitude events. Many devastating earthquakes, some of them tsunami-triggering, inflicted heavy loss and considerable economic damage to the region. From 1920 to present, three earthquakes with magnitudes of about 8.0 (Mw 8.2, 25 November 1941; Ms 8.0, 25 February 1969; and Mw 7.9, 26 May 1975) occurred in the oceanic region, and four earthquakes with magnitudes of about 7.0 (Mw 7.1, 8 May 1939, Santa Maria Island and Mw 7.1, January 1980, Terceira and Graciosa Islands, both in the Azores; Ms 7.1, 20 May 1931, Azores-Gibraltar fracture zone; and Mw 7.3, 10 October 1980, El Asnam, Algeria) occurred along the western part of the Eurasia-Nubia plate boundary. In general, large earthquakes (M ≥7) occur within the oceanic region, with the exception of the El Asnam (Algeria) earthquakes. Some of these events caused extensive damage. The 1755 Lisbon earthquake (˜Mw 9) on the Portugal Atlantic margin, about 200 km W-SW of Cape St. Vincent, was followed by a tsunami and fires that caused the near-total destruction of Lisbon and adjacent areas. Estimates of the death toll in Lisbon alone (~70,000) make it one of the deadliest earthquakes in history. Measured in lives lost, the 1926, 1980 and 1998 Azores earthquakes (Portugal), the 1954 and 1980 El Asnam earthquakes (North Algeria), the 1994 and 2004 Alhoceima earthquakes (North Morocco), and the 2003 Boumerdes earthquakes (North Algeria) were the worst earthquakes in the past 120 years in the study area. Hence, this region has experienced many large and damaging earthquakes. The city of Cairo (Egypt) was struck in October 1992 by an Mw 5.8 magnitude earthquake, which caused large damage. In 1935, the Syrte region in Libya experienced an M6.9 earthquake with severe damage. Generally, North Africa has experienced moderate earthquakes. However, the region remains vulnerable due to the shallow seismicity, the poor mechanical properties of its soil and local site conditions, and the consequent strength of the ground shaking. Knowing the behaviour of a seismogenic area, particularly the fault zone, will lead us to better assess the hazard and risk in and around large urban areas. In order to mitigate the destructive impact of the earthquakes, the regional seismic hazard in North Africa is assessed using different approaches (ex. deterministic and probabilistic) using historical and instrumental seismicity, earthquake sources, seismotectonic zonation, structural models and attenuation laws. As a result, reliable seismic hazard maps are produced in terms of maximum displacement and in terms of maximum intensity map. This research is funded by the Fundação para a Ciência e a Tecnologia (FCT, Portugal) under the project ICT-UID/GEO/04683/2013. This study also was conducted within the scope of the MEDYNA FP7-PEOPLE-2013-IRSES project, WP-1: Present-day Kinematics and seismic hazards, funded by the Seventh Framework European Programme.

Earthquake damage to schools

USGS Publications Warehouse

McCullough, Heather

1994-01-01

These unusual slides show earthquake damage to school and university buildings around the world. They graphically illustrate the potential danger to our schools, and to the welfare of our children, that results from major earthquakes. The slides range from Algeria, where a collapsed school roof is held up only by students' desks; to Anchorage, Alaska, where an elementary school structure has split in half; to California and other areas, where school buildings have sustained damage to walls, roofs, and chimneys. Interestingly, all the United States earthquakes depicted in this set of slides occurred either on a holiday or before or after school hours, except the 1935 tremor in Helena, Montana, which occurred at 11:35 am. It undoubtedly would have caused casualties had the schools not been closed days earlier by Helena city officials because of a damaging foreshock. Students in Algeria, the People's Republic of China, Armenia, and other stricken countries were not so fortunate. This set of slides represents 17 destructive earthquakes that occurred in 9 countries, and covers more than a century--from 1886 to 1988. Two of the tremors, both of which occurred in the United States, were magnitude 8+ on the Richter Scale, and four were magnitude 7-7.9. The events represented by the slides (see table below) claimed more than a quarter of a million lives.

A revised “earthquake report” questionaire

USGS Publications Warehouse

Stover, C.; Reagor, G.; Simon, R.

1976-01-01

The U.S geological Survey is responsible for conducting intensity and damage surveys following felt or destructive earthquakes in the United States. Shortly after a felt or damaging earthquake occurs, a canvass of the affected area is made. Specially developed questionnaires are mailed to volunteer observers located within the estimated felt area. These questionnaires, "Earthquake Reports," are filled out by the observers and returned to the Survey's National Earthquake Information Service, which is located in Colorado. They are then evaluated, and, based on answers to questions about physical effects seen or felt, each canvassed location is assigned to the various locations, they are plotted on an intensity distribution map. When all of the intensity data have been plotted, isoseismals can then be contoured through places where equal intensity was experienced. The completed isoseismal map yields a detailed picture of the earthquake, its effects, and its felt area. All of the data and maps are published quarterly in a U.S Geological Survey Circular series entitled "Earthquakes in the United States".  

Structural damages observed in state buildings after Simav/Turkey earthquake occurred on 19 May 2011

NASA Astrophysics Data System (ADS)

Tama, Y. S.

2012-08-01

Different levels of damages occurred in state buildings, especially in educational facilities, during the Simav earthquake (ML=5.7) on 19 May 2011. A site survey was carried out in the area after the earthquake, where six state buildings were examined in detail. The results of the survey showed that main reasons for the formation of damages in these buildings are the use of low strength concrete, insufficient reinforcement, inappropriate detailing, and low-quality workmanship. The investigated buildings were also evaluated by P25-rapid assessment method. The method demonstrates that two of the buildings in question are in "high risk band"; the other two fall into "detailed evaluation band", and the rest are in the "low risk band". This figure also matches with the damages observed in the site survey.

Understanding the distribution of strong motions and the damage caused during the September 19th, 2017 earthquake

NASA Astrophysics Data System (ADS)

Aguirre, J.; Ramirez-Guzman, L.; Leonardo Suárez, M.; Quintanar, L.

2017-12-01

On September 19, 2017, a normal fault earthquake of magnitude Mw 7.1 occurred 120 km from Mexico City. The quake generated large accelerations, more than 200 cm/s*s at least in two stations in Mexico City, where there was extensive damage. The damage pattern, which includes more than 40 building collapses, differs from the one induced by the 1985 Michoacan earthquake. While the observed accelerations in stations located in the Hill and Transition zones are the largest ever recorded, in the Lake zone the intensities were lower than those recorded in 1985. Even though the proximity of the epicenter could partially explain the accelerations, other factors need to be explored to understand the nuances of the ground motion. Unlike 1985, there is a substantially larger number of acceleration records in Mexico City, operated and maintained by different institutions. In this paper, we present the analysis of acceleration records and 3D numerical simulations to understand if effects such as focusing and directionality participate in the amplified motion. Finally, transfer functions between Lake and Hill zones and response and design spectral values are analyzed in regions where the building code requirements were exceeded. Acknowledgments: Records used in this research are obtained, processed and maintained by the National Autonomous University of Mexico through the Seismic Instrumentation Unit of the Institute of Engineering and the National Seismological Service of the Institute of Geophysics. The Centro de Intrumentacion y Registro Sismico A.C. (CIRES) kindly provided their records. This Project was funded in part by the Secretaria de Ciencia, Tecnología e Innovación (SECITI) of Mexico City. Project SECITI/073/2016.

What is the earthquake fracture energy?

NASA Astrophysics Data System (ADS)

Di Toro, G.; Nielsen, S. B.; Passelegue, F. X.; Spagnuolo, E.; Bistacchi, A.; Fondriest, M.; Murphy, S.; Aretusini, S.; Demurtas, M.

2016-12-01

The energy budget of an earthquake is one of the main open questions in earthquake physics. During seismic rupture propagation, the elastic strain energy stored in the rock volume that bounds the fault is converted into (1) gravitational work (relative movement of the wall rocks bounding the fault), (2) in- and off-fault damage of the fault zone rocks (due to rupture propagation and frictional sliding), (3) frictional heating and, of course, (4) seismic radiated energy. The difficulty in the budget determination arises from the measurement of some parameters (e.g., the temperature increase in the slipping zone which constraints the frictional heat), from the not well constrained size of the energy sinks (e.g., how large is the rock volume involved in off-fault damage?) and from the continuous exchange of energy from different sinks (for instance, fragmentation and grain size reduction may result from both the passage of the rupture front and frictional heating). Field geology studies, microstructural investigations, experiments and modelling may yield some hints. Here we discuss (1) the discrepancies arising from the comparison of the fracture energy measured in experiments reproducing seismic slip with the one estimated from seismic inversion for natural earthquakes and (2) the off-fault damage induced by the diffusion of frictional heat during simulated seismic slip in the laboratory. Our analysis suggests, for instance, that the so called earthquake fracture energy (1) is mainly frictional heat for small slips and (2), with increasing slip, is controlled by the geometrical complexity and other plastic processes occurring in the damage zone. As a consequence, because faults are rapidly and efficiently lubricated upon fast slip initiation, the dominant dissipation mechanism in large earthquakes may not be friction but be the off-fault damage due to fault segmentation and stress concentrations in a growing region around the fracture tip.

Flash-sourcing or the rapid detection and characterisation of earthquake effects through clickstream data analysis

NASA Astrophysics Data System (ADS)

Bossu, R.; Mazet-Roux, G.; Roussel, F.; Frobert, L.

2011-12-01

Rapid characterisation of earthquake effects is essential for a timely and appropriate response in favour of victims and/or of eyewitnesses. In case of damaging earthquakes, any field observations that can fill the information gap characterising their immediate aftermath can contribute to more efficient rescue operations. This paper presents the last developments of a method called "flash-sourcing" addressing these issues. It relies on eyewitnesses, the first informed and the first concerned by an earthquake occurrence. More precisely, their use of the EMSC earthquake information website (www.emsc-csem.org) is analysed in real time to map the area where the earthquake was felt and identify, at least under certain circumstances zones of widespread damage. The approach is based on the natural and immediate convergence of eyewitnesses on the website who rush to the Internet to investigate cause of the shaking they just felt causing our traffic to increase The area where an earthquake was felt is mapped simply by locating Internet Protocol (IP) addresses during traffic surges. In addition, the presence of eyewitnesses browsing our website within minutes of an earthquake occurrence excludes the possibility of widespread damage in the localities they originate from: in case of severe damage, the networks would be down. The validity of the information derived from this clickstream analysis is confirmed by comparisons with EMS98 macroseismic map obtained from online questionnaires. The name of this approach, "flash-sourcing", is a combination of "flash-crowd" and "crowdsourcing" intending to reflect the rapidity of the data collation from the public. For computer scientists, a flash-crowd names a traffic surge on a website. Crowdsourcing means work being done by a "crowd" of people; It also characterises Internet and mobile applications collecting information from the public such as online macroseismic questionnaires. Like crowdsourcing techniques, flash-sourcing is a crowd-to-agency system, but unlike them it is not based on declarative information (e.g. answers to a questionnaire) but on implicit data, clickstream observed on our website. We present first the main improvements of the method, improved detection of traffic surges, and a way to instantly map areas affected by severe damage or network disruptions. The second part describes how the derived information improves and fastens public earthquake information and, beyond seismology, what it can teach us on public behaviour when facing an earthquake. Finally, the discussion will focus on the future evolutions and how flash-sourcing could ultimately improve earthquake response.

Earthquake-Induced Building Damage Assessment Based on SAR Correlation and Texture

NASA Astrophysics Data System (ADS)

Gong, Lixia; Li, Qiang; Zhang, Jingfa

2016-08-01

Comparing with optical Remote Sensing, the Synthetic Aperture Radar (SAR) has unique advantages as applied to seismic hazard monitoring and evaluation. SAR can be helpful in the whole process of after an earthquake, which can be divided into three stages. On the first stage, pre-disaster imagery provides history information of the attacked area. On the mid-term stage, up-to-date thematic maps are provided for disaster relief. On the later stage, information is provided to assist secondary disaster monitoring, post- disaster assessment and reconstruction second stage. In recent years, SAR has become an important data source of earthquake damage analysis and evaluation.Correlation between pre- and post-event SAR images is considered to be related with building damage. There will be a correlation decrease when the building collapsed in a shock. Whereas correlation decrease does not definitely indicate building changes. Correlation is also affected by perpendicular baseline, the ground coverage type, atmospheric change and other natural conditions, data processing and other factors. Building samples in the earthquake are used to discriminate the relation between damage degree and SAR correlation.

The Extraction of Post-Earthquake Building Damage Informatiom Based on Convolutional Neural Network

NASA Astrophysics Data System (ADS)

Chen, M.; Wang, X.; Dou, A.; Wu, X.

2018-04-01

The seismic damage information of buildings extracted from remote sensing (RS) imagery is meaningful for supporting relief and effective reduction of losses caused by earthquake. Both traditional pixel-based and object-oriented methods have some shortcoming in extracting information of object. Pixel-based method can't make fully use of contextual information of objects. Object-oriented method faces problem that segmentation of image is not ideal, and the choice of feature space is difficult. In this paper, a new stratage is proposed which combines Convolution Neural Network (CNN) with imagery segmentation to extract building damage information from remote sensing imagery. the key idea of this method includes two steps. First to use CNN to predicate the probability of each pixel and then integrate the probability within each segmentation spot. The method is tested through extracting the collapsed building and uncollapsed building from the aerial image which is acquired in Longtoushan Town after Ms 6.5 Ludian County, Yunnan Province earthquake. The results show that the proposed method indicates its effectiveness in extracting damage information of buildings after earthquake.

Improving PAGER's real-time earthquake casualty and loss estimation toolkit: a challenge

USGS Publications Warehouse

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

2012-01-01

We describe the on-going developments of PAGER’s loss estimation models, and discuss value-added web content that can be generated related to exposure, damage and loss outputs for a variety of PAGER users. These developments include identifying vulnerable building types in any given area, estimating earthquake-induced damage and loss statistics by building type, and developing visualization aids that help locate areas of concern for improving post-earthquake response efforts. While detailed exposure and damage information is highly useful and desirable, significant improvements are still necessary in order to improve underlying building stock and vulnerability data at a global scale. Existing efforts with the GEM’s GED4GEM and GVC consortia will help achieve some of these objectives. This will benefit PAGER especially in regions where PAGER’s empirical model is less-well constrained; there, the semi-empirical and analytical models will provide robust estimates of damage and losses. Finally, we outline some of the challenges associated with rapid casualty and loss estimation that we experienced while responding to recent large earthquakes worldwide.

A new Bayesian Inference-based Phase Associator for Earthquake Early Warning

NASA Astrophysics Data System (ADS)

Meier, Men-Andrin; Heaton, Thomas; Clinton, John; Wiemer, Stefan

2013-04-01

State of the art network-based Earthquake Early Warning (EEW) systems can provide warnings for large magnitude 7+ earthquakes. Although regions in the direct vicinity of the epicenter will not receive warnings prior to damaging shaking, real-time event characterization is available before the destructive S-wave arrival across much of the strongly affected region. In contrast, in the case of the more frequent medium size events, such as the devastating 1994 Mw6.7 Northridge, California, earthquake, providing timely warning to the smaller damage zone is more difficult. For such events the "blind zone" of current systems (e.g. the CISN ShakeAlert system in California) is similar in size to the area over which severe damage occurs. We propose a faster and more robust Bayesian inference-based event associator, that in contrast to the current standard associators (e.g. Earthworm Binder), is tailored to EEW and exploits information other than only phase arrival times. In particular, the associator potentially allows for reliable automated event association with as little as two observations, which, compared to the ShakeAlert system, would speed up the real-time characterizations by about ten seconds and thus reduce the blind zone area by up to 80%. We compile an extensive data set of regional and teleseismic earthquake and noise waveforms spanning a wide range of earthquake magnitudes and tectonic regimes. We pass these waveforms through a causal real-time filterbank with passband filters between 0.1 and 50Hz, and, updating every second from the event detection, extract the maximum amplitudes in each frequency band. Using this dataset, we define distributions of amplitude maxima in each passband as a function of epicentral distance and magnitude. For the real-time data, we pass incoming broadband and strong motion waveforms through the same filterbank and extract an evolving set of maximum amplitudes in each passband. We use the maximum amplitude distributions to check whether the incoming waveforms are consistent with amplitude and frequency patterns of local earthquakes by means of a maximum likelihood approach. If such a single-station event likelihood is larger than a predefined threshold value we check whether there are neighboring stations that also have single-station event likelihoods above the threshold. If this is the case for at least one other station, we evaluate whether the respective relative arrival times are in agreement with a common earthquake origin (assuming a simple velocity model and using an Equal Differential Time location scheme). Additionally we check if there are stations where, given the preliminary location, observations would be expected but were not reported ("not-yet-arrived data"). Together, the single-station event likelihood functions and the location likelihood function constitute the multi-station event likelihood function. This function can then be combined with various types of prior information (such as station noise levels, preceding seismicity, fault proximity, etc.) to obtain a Bayesian posterior distribution, representing the degree of belief that the ensemble of the current real-time observations correspond to a local earthquake, rather than to some other signal source irrelevant for EEW. Additional to the reduction of the blind zone size, this approach facilitates the eventual development of an end-to-end probabilistic framework for an EEW system that provides systematic real-time assessment of the risk of false alerts, which enables end users of EEW to implement damage mitigation strategies only above a specified certainty level.

Earthquake and Tsunami Disaster Mitigation in the Marmara Region and Disaster Education in Turkey Part3

NASA Astrophysics Data System (ADS)

Kaneda, Yoshiyuki; Ozener, Haluk; Meral Ozel, Nurcan; Kalafat, Dogan; Ozgur Citak, Seckin; Takahashi, Narumi; Hori, Takane; Hori, Muneo; Sakamoto, Mayumi; Pinar, Ali; Oguz Ozel, Asim; Cevdet Yalciner, Ahmet; Tanircan, Gulum; Demirtas, Ahmet

2017-04-01

There have been many destructive earthquakes and tsunamis in the world.The recent events are, 2011 East Japan Earthquake/Tsunami in Japan, 2015 Nepal Earthquake and 2016 Kumamoto Earthquake in Japan, and so on. And very recently a destructive earthquake occurred in Central Italy. In Turkey, the 1999 Izmit Earthquake as the destructive earthquake occurred along the North Anatolian Fault (NAF). The NAF crosses the Sea of Marmara and the only "seismic gap" remains beneath the Sea of Marmara. Istanbul with high population similar to Tokyo in Japan, is located around the Sea of Marmara where fatal damages expected to be generated as compound damages including Tsunami and liquefaction, when the next destructive Marmara Earthquake occurs. The seismic risk of Istanbul seems to be under the similar risk condition as Tokyo in case of Nankai Trough earthquake and metropolitan earthquake. It was considered that Japanese and Turkish researchers can share their own experiences during past damaging earthquakes and can prepare for the future large earthquakes in cooperation with each other. Therefore, in 2013 the two countries, Japan and Turkey made an agreement to start a multidisciplinary research project, MarDiM SATREPS. The Project runs researches to aim to raise the preparedness for possible large-scale earthquake and Tsunami disasters in Marmara Region and it has four research groups with the following goals. 1) The first one is Marmara Earthquake Source region observational research group. This group has 4 sub-groups such as Seismicity, Geodesy, Electromagnetics and Trench analyses. Preliminary results such as seismicity and crustal deformation on the sea floor in Sea of Marmara have already achieved. 2) The second group focuses on scenario researches of earthquake occurrence along the North Anatolia Fault and precise tsunami simulation in the Marmara region. Research results from this group are to be the model of earthquake occurrence scenario in Sea of Marmara and the case studies with advanced tsunami simulation for measure cities. 3) Aims of the third group are improvements and constructions of seismic characterizations and damage predictions based on observation researches and precise simulations. Research results from this group will be very important for disaster measures. 4) The fourth group is promoting disaster educations using research result visuals. The mission of this group is very important for information dissemination and practical and effective disaster education in Turkey. The research results from all components will be integrated and utilized for disaster mitigation in Marmara region and disaster education in Turkey. Updated research results of the MarDiM SATREPS Project will be officially presented toward the end of the Project period, which is March 2018.

Effects of the earthquake of March 27, 1964, on air and water transport, communications, and utilities systems in south-central Alaska: Chapter B in The Alaska earthquake, March 27, 1964: effects on transportation, communications, and utilities

USGS Publications Warehouse

Eckel, Edwin B.

1967-01-01

The earthquake of March 27, 1964, wrecked or severely hampered all forms of transportation, all utilities, and all communications systems over a very large part of south-central Alaska. Effects on air transportation were minor as compared to those on the water, highway, and railroad transport systems. A few planes were damaged or wrecked by seismic vibration or by flooding. Numerous airport facilities were damaged by vibration or by secondary effects of the earthquake, notably seismic sea and landslide-generated waves, tectonic subsidence, and compaction. Nearly all air facilities were partly or wholly operational within a few hours after the earthquake. The earthquake inflicted enormous damage on the shipping industry, which is indispensable to a State that imports fully 90 percent of its requirements—mostly by water—and whose largest single industry is fishing. Except for those of Anchorage, all port facilities in the earthquake-affected area were destroyed or made inoperable by submarine slides, waves, tectonic uplift, and fire. No large vessels were lost, but more than 200 smaller ones (mostly crab or salmon boats) were lost or severely damaged. Navigation aids were destroyed, and hitherto well-known waterways were greatly altered by uplift or subsidence. All these effects wrought far-reaching changes in the shipping economy of Alaska, many of them to its betterment. Virtually all utilities and communications in south-central Alaska were damaged or wrecked by the earthquake, but temporary repairs were effected in remarkably short times. Communications systems were silenced almost everywhere by loss of power or by downed lines; their place was quickly taken by a patchwork of self-powered radio transmitters. A complex power-generating system that served much of the stricken area from steam, diesel, and hydrogenerating plants was disrupted in many places by vibration damage to equipment and by broken transmission lines. Landslides in Anchorage broke gas-distribution lines in many places, but the main transmission line from the Kenai Peninsula was virtually undamaged. Petroleum supplies were disrupted, principally by breakage or loss of storage tanks caused by seismic vibration, slides, waves, and fire. Water-supply and sewer lines were also broken in many towns.

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.

Effects of topographic position and geology on shaking damage to residential wood-framed structures during the 2003 San Simeon earthquake, western San Luis obispo county, California

USGS Publications Warehouse

McCrink, T.P.; Wills, C.J.; Real, C.R.; Manson, M.W.

2010-01-01

A statistical evaluation of shaking damage to wood-framed houses caused by the 2003 M6.5 San Simeon earthquake indicates that both the rate and severity of damage, independent of structure type, are significantly greater on hilltops compared to hill slopes when underlain by Cretaceous or Tertiary sedimentary rocks. This increase in damage is interpreted to be the result of topographic amplification. An increase in the damage rate is found for all structures built on Plio-Pleistocene rocks independent of topographic position, and this is interpreted to be the result of amplified shaking caused by geologic site response. Damage rate and severity to houses built on Tertiary rocks suggest that amplification due to both topographic position and geologic site response may be occurring in these rocks, but effects from other topographic parameters cannot be ruled out. For all geologic and topographic conditions, houses with raised foundations are more frequently damaged than those with slab foundations. However, the severity of damage to houses on raised foundations is only significantly greater for those on hill slopes underlain by Tertiary rocks. Structures with some damage-resistant characteristics experienced greater damage severity on hilltops, suggesting a spectral response to topographic amplification. ?? 2010, Earthquake Engineering Research Institute.

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 unlikely to sustain heavy damage proved sound. In addition, we compared mapped liquefaction extents (derived from post-earthquake aerial photographs) from the 4 Sept 2010 Mw7.1 and 22 Feb 2011 Mw6.2 earthquakes with our liquefaction susceptibility map. The overall area of liquefaction for these two earthquakes was similar, and statistics show that for the first (large regional) earthquake, c. 93% of mapped liquefaction fell within the liquefaction-prone area, and for the second (local, high peak ground acceleration) earthquake, almost 99% fell within the liquefaction-prone area. We conclude that basic geological and groundwater data when coupled with LiDAR data can usefully delineate areas susceptible to liquefaction from those unlikely to suffer damaging liquefaction. We believe that these techniques can be used successfully in many other cities around the world.

Earthquakes, September-October 1978

USGS Publications Warehouse

Person, W.J.

1979-01-01

The months of September and October were somewhat quiet seismically speaking. One major earthquake, magnitude (M) 7.7 occurred in Iran on September 16. In Germany, a magntidue 5.0 earthquake caused damage and considerable alarm to many people in parts of that country. In the United States, the largest earthquake occurred along the California-Nevada border region. 

Geotechnical aspects of the 2016 MW 6.2, MW 6.0, and MW 7.0 Kumamoto earthquakes

USGS Publications Warehouse

Kayen, Robert E.; Dashti, Shideh; Kokusho, T.; Hazarika, H.; Franke, Kevin; Oettle, N. K.; Wham, Brad; Ramirez Calderon, Jenny; Briggs, Dallin; Guillies, Samantha; Cheng, Katherine; Tanoue, Yutaka; Takematsu, Katsuji; Matsumoto, Daisuke; Morinaga, Takayuki; Furuichi, Hideo; Kitano, Yuuta; Tajiri, Masanori; Chaudhary, Babloo; Nishimura, Kengo; Chu, Chu

2017-01-01

The 2016 Kumamoto earthquakes are a series of events that began with an earthquake of moment magnitude 6.2 on the Hinagu Fault on April 14, 2016, followed by another foreshock of moment magnitude 6.0 on the Hinagu Fault on April 15, 2016, and a larger moment magnitude 7.0 event on the Futagawa Fault on April 16, 2016 beneath Kumamoto City, Kumamoto Prefecture on Kyushu, Japan. These events are the strongest earthquakes recorded in Kyushu during the modern instrumental era. The earthquakes resulted in substantial damage to infrastructure, buildings, cultural heritage of Kumamoto Castle, roads and highways, slopes, and river embankments due to earthquake-induced landsliding and debris flows. Surface fault rupture produced offset and damage to roads, buildings, river levees, and an agricultural dam. Surprisingly, given the extremely intense earthquake motions, liquefaction occurred only in a few districts of Kumamoto City and in the port areas indicating that the volcanic soils were less susceptible to liquefying than expected given the intensity of earthquake shaking, a significant finding from this event.

Vulnerability of populations and man-made facilities to seismic hazards

NASA Astrophysics Data System (ADS)

Badal, J.; Vazquez-Prada, M.; Gonzalez, A.; Chourak, M.; Samardzhieva, E.; Zhang, Z.

2003-04-01

Earthquakes become major societal risks when they impinge on vulnerable populations. According to the available worldwide data during the twentieth century (NEIC Catalog of Earthquakes 1980-1999), almost half a thousand of earthquakes resulted in more than 1,615,000 human victims. Besides human casualty levels, destructive earthquakes frequently inflict huge economic losses. An additional problem of very different nature, but also worthy of being considered in a damage and loss analysis, is the direct cost associated with the damages derived from a strong seismic impact. We focus our attention on both aspects to their rapid quantitative assessment, and to lessen the earthquake disaster in areas affected by relatively strong earthquakes. Our final goal is the knowledge of potential losses from earthquakes to forward national programs in emergency management, and consequently the minimization of the life loss due to earthquakes, and to aid in response and recovery tasks. For this purpose we follow a suitable and comprehensible methodology for risk-based loss analysis, and simulate the occurence of a seismic event in densely populated areas of Spain.

Research on Optimal Observation Scale for Damaged Buildings after Earthquake Based on Optimal Feature Space

NASA Astrophysics Data System (ADS)

Chen, J.; Chen, W.; Dou, A.; Li, W.; Sun, Y.

2018-04-01

A new information extraction method of damaged buildings rooted in optimal feature space is put forward on the basis of the traditional object-oriented method. In this new method, ESP (estimate of scale parameter) tool is used to optimize the segmentation of image. Then the distance matrix and minimum separation distance of all kinds of surface features are calculated through sample selection to find the optimal feature space, which is finally applied to extract the image of damaged buildings after earthquake. The overall extraction accuracy reaches 83.1 %, the kappa coefficient 0.813. The new information extraction method greatly improves the extraction accuracy and efficiency, compared with the traditional object-oriented method, and owns a good promotional value in the information extraction of damaged buildings. In addition, the new method can be used for the information extraction of different-resolution images of damaged buildings after earthquake, then to seek the optimal observation scale of damaged buildings through accuracy evaluation. It is supposed that the optimal observation scale of damaged buildings is between 1 m and 1.2 m, which provides a reference for future information extraction of damaged buildings.

The October 12, 1992, Dahshur, Egypt, Earthquake

USGS Publications Warehouse

Thenhaus, P.C.; Celebi, M.; Sharp, R.V.

1993-01-01

We were part of an international reconnaissance team that investigated the Dahsur earthquake. This article summarizes our findings and points out how even a relatively moderate sized earthquake can cause widespread damage and a large number of casualities. 

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.

The ShakeOut Earthquake Scenario - A Story That Southern Californians Are Writing

USGS Publications Warehouse

Perry, Suzanne; Cox, Dale; Jones, Lucile; Bernknopf, Richard; Goltz, James; Hudnut, Kenneth; Mileti, Dennis; Ponti, Daniel; Porter, Keith; Reichle, Michael; Seligson, Hope; Shoaf, Kimberley; Treiman, Jerry; Wein, Anne

2008-01-01

The question is not if but when southern California will be hit by a major earthquake - one so damaging that it will permanently change lives and livelihoods in the region. How severe the changes will be depends on the actions that individuals, schools, businesses, organizations, communities, and governments take to get ready. To help prepare for this event, scientists of the U.S. Geological Survey (USGS) have changed the way that earthquake scenarios are done, uniting a multidisciplinary team that spans an unprecedented number of specialties. The team includes the California Geological Survey, Southern California Earthquake Center, and nearly 200 other partners in government, academia, emergency response, and industry, working to understand the long-term impacts of an enormous earthquake on the complicated social and economic interactions that sustain southern California society. This project, the ShakeOut Scenario, has applied the best current scientific understanding to identify what can be done now to avoid an earthquake catastrophe. More information on the science behind this project will be available in The ShakeOut Scenario (USGS Open-File Report 2008-1150; http://pubs.usgs.gov/of/2008/1150/). The 'what if?' earthquake modeled in the ShakeOut Scenario is a magnitude 7.8 on the southern San Andreas Fault. Geologists selected the details of this hypothetical earthquake by considering the amount of stored strain on that part of the fault with the greatest risk of imminent rupture. From this, seismologists and computer scientists modeled the ground shaking that would occur in this earthquake. Engineers and other professionals used the shaking to produce a realistic picture of this earthquake's damage to buildings, roads, pipelines, and other infrastructure. From these damages, social scientists projected casualties, emergency response, and the impact of the scenario earthquake on southern California's economy and society. The earthquake, its damages, and resulting losses are one realistic outcome, deliberately not a worst-case scenario, rather one worth preparing for and mitigating against. Decades of improving the life-safety requirements in building codes have greatly reduced the risk of death in earthquakes, yet southern California's economic and social systems are still vulnerable to large-scale disruptions. Because of this, the ShakeOut Scenario earthquake would dramatically alter the nature of the southern California community. Fortunately, steps can be taken now that can change that outcome and repay any costs many times over. The ShakeOut Scenario is the first public product of the USGS Multi-Hazards Demonstration Project, created to show how hazards science can increase a community's resiliency to natural disasters through improved planning, mitigation, and response.

Modified Mercalli Intensity for scenario earthquakes in Evansville, Indiana

USGS Publications Warehouse

Cramer, Chris; Haase, Jennifer; Boyd, Oliver

2012-01-01

Evansville, Indiana, has experienced minor damage from earthquakes several times in the past 200 years. Because of this history and the fact that Evansville is close to the Wabash Valley and New Madrid seismic zones, there is concern about the 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. Earthquake-hazard maps provide one way of conveying such estimates of strong ground shaking and will help the region prepare for future earthquakes and reduce earthquake-caused losses.

Re-examination of the original questionnaire documents for the 1944 Tonankai, 1945 Mikawa, and 1946 Nanaki earthquakes

NASA Astrophysics Data System (ADS)

Harada, Tomoya; Satake, Kenji; Furumura, Takashi

2016-04-01

With the object of estimating seismic intensity, the Earthquakes Research Institute (ERI) of the University of Tokyo performed questionnaire surveys for the significant (destructive or large/great) earthquakes from 1943 to 1988 (Kayano, 1990, BERI). In these surveys, Kawasumi (1943)'s 12-class seismic intensity scale similar to the Modified Mercalli scale (MM-scale) was used. Survey results for earthquakes after 1950 were well investigated and published (e.g. Kayano and Komaki, 1977, BERI; Kayano and Sato, 1975, BERI), but the survey results for earthquakes in the 1940s have not been published and original documents of the surveys was missing. Recently, the original sheets of the surveys for the five earthquakes in the 1940s with more than 1,000 casualties were discovered in the ERI warehouse, although they are incomplete (Tsumura et al, 2010). They are from the 1943 Tottori (M 7.2), 1944 Tonankai (M 7.9), 1945 Mikawa (M 6.8), 1946 Nankai (M 8.0), and 1948 Fukui (M 7.1) earthquakes. In this study, we examined original questionnaire and summary sheets for the 1944 Tonankai, 1945 Mikawa, and 1946 Nanaki earthquakes, and estimated the distributions of seismic intensity, various kinds of damage, and human behaviors in detail. Numbers of the survey points for the 1944, 1945, and 1946 event are 287, 145, and 1,014, respectively. The numbers for the 1944 and 1945 earthquakes are much fewer than that of the 1946 event, because they occurred during the last years of World War II. The 1944 seismic intensities in the prefectures near the source region (Aichi, Mie, Shizuoka, and Gifu Pref.) tend to be high. However, the 1944 intensities are also high and damage is serious at the Suwa Lake shore in Nagano Pref. which is about 240 km far from the source region because seismic waves are amplified dramatically in the thick sediment in the Suwa Basin. Seismic intensities of the 1945 Mikawa earthquake near the source region in Aichi Pref. were very high (X-XI). However, the intensities rapidly decrease with the epicenter distance, and show relatively low numbers (IV-VI) outside Aichi Pref. because the 1945 earthquake was a shallow crust earthquake with moderate size (M 6.8). The maximum seismic intensity of the 1946 Nankai earthquake estimated from the damage of Japanese-style wooden houses reach X-XI near the source-rupture area such as in Shikoku Island and Wakayama and Okayama Prefectures. The damage of wooden houses was more serious in the plains and basins of populated cities than that in the mountainous regions. The estimated seismic intensities from other damage (bridges, stone walls, underground pipes, etc.) also exceed X. Acknowledgement: This study was supported by the MEXT's "New disaster mitigation research project on Mega thrust earthquakes around Nankai/Ryukyu subduction zones".

Localised Effects of a Mega-Disturbance: Spatiotemporal Responses of Intertidal Sandy Shore Communities to the 2010 Chilean Earthquake.

PubMed

Sepúlveda, Roger D; Valdivia, Nelson

2016-01-01

Determining the effects of unpredictable disturbances on dynamic ecological systems is challenged by the paucity of appropriate temporal and spatial coverage of data. On 27 February 2010, an 8.8 Mw mega-earthquake and tsunami struck central Chile and caused coastal land-level changes, massive damage to coastal infrastructure, and widespread mortality of coastal organisms. Wave-exposed sandy beaches showed significant changes of species abundances from before to after the earthquake, but the highly dynamic biotic and abiotic conditions of these habitats make difficult to draw clear-cut conclusions from these patterns. Here, we analysed a beyond-BACI (Before-After Control-Impact) sampling design to test whether the effects of the Maule earthquake on sandy-shore species diversity, abundance, and structure were heterogeneous along the shore. Invertebrate species abundances were quantified before (i.e. February 2010) and after (i.e. March 2010, September 2010, and March 2011) the earthquake at three sandy shores randomly located within the earthquake rupture area and three sites within a "control" area located >400 km southward from epicentre. Immediately after the earthquake took place, the three sites located in the rupture area showed anomalous beach-profile uplifts that did not comply with the erosion (i.e. "negative" uplifts) that regularly occurs during late summer in the region. Species richness, abundance, and community structure significantly varied from before to after the strike, but these patterns of change varied among sites within both areas. Only the site with the strongest and persistent beach-profile uplift within the rupture area showed significant concomitant changes in species richness and community structure; after 13 months, this community showed a similar multivariate structure to the before-disturbance state. This site, in particular, was located in the section of the rupture area that received most of the impact of the after-earthquake tsunami. Therefore, our results suggest that the effects of the Maule mega-earthquake on the ecological communities were spatially heterogeneous and highly localised. We suggest that high mobility and other species' adaptations to the dynamic environmental conditions of sandy beaches might explain the comparatively high resilience of these assemblages. With this work we hope to motivate further experimental research on the role of individual- and population-level properties in the response of sandy-beach communities to interacting sources of disturbances.

Localised Effects of a Mega-Disturbance: Spatiotemporal Responses of Intertidal Sandy Shore Communities to the 2010 Chilean Earthquake

PubMed Central

Sepúlveda, Roger D.; Valdivia, Nelson

2016-01-01

Determining the effects of unpredictable disturbances on dynamic ecological systems is challenged by the paucity of appropriate temporal and spatial coverage of data. On 27 February 2010, an 8.8 Mw mega-earthquake and tsunami struck central Chile and caused coastal land-level changes, massive damage to coastal infrastructure, and widespread mortality of coastal organisms. Wave-exposed sandy beaches showed significant changes of species abundances from before to after the earthquake, but the highly dynamic biotic and abiotic conditions of these habitats make difficult to draw clear-cut conclusions from these patterns. Here, we analysed a beyond-BACI (Before-After Control-Impact) sampling design to test whether the effects of the Maule earthquake on sandy-shore species diversity, abundance, and structure were heterogeneous along the shore. Invertebrate species abundances were quantified before (i.e. February 2010) and after (i.e. March 2010, September 2010, and March 2011) the earthquake at three sandy shores randomly located within the earthquake rupture area and three sites within a “control” area located >400 km southward from epicentre. Immediately after the earthquake took place, the three sites located in the rupture area showed anomalous beach-profile uplifts that did not comply with the erosion (i.e. “negative” uplifts) that regularly occurs during late summer in the region. Species richness, abundance, and community structure significantly varied from before to after the strike, but these patterns of change varied among sites within both areas. Only the site with the strongest and persistent beach-profile uplift within the rupture area showed significant concomitant changes in species richness and community structure; after 13 months, this community showed a similar multivariate structure to the before-disturbance state. This site, in particular, was located in the section of the rupture area that received most of the impact of the after-earthquake tsunami. Therefore, our results suggest that the effects of the Maule mega-earthquake on the ecological communities were spatially heterogeneous and highly localised. We suggest that high mobility and other species’ adaptations to the dynamic environmental conditions of sandy beaches might explain the comparatively high resilience of these assemblages. With this work we hope to motivate further experimental research on the role of individual- and population-level properties in the response of sandy-beach communities to interacting sources of disturbances. PMID:27383744

Introducing ShakeMap to potential users in Puerto Rico using scenarios of damaging historical and probable earthquakes

NASA Astrophysics Data System (ADS)

Huerfano, V. A.; Cua, G.; von Hillebrandt, C.; Saffar, A.

2007-12-01

The island of Puerto Rico has a long history of damaging earthquakes. Major earthquakes from off-shore sources have affected Puerto Rico in 1520, 1615, 1670, 1751, 1787, 1867, and 1918 (Mueller et al, 2003; PRSN Catalogue). Recent trenching has also yielded evidence of possible M7.0 events inland (Prentice, 2000). The high seismic hazard, large population, high tsunami potential and relatively poor construction practice can result in a potentially devastating combination. Efficient emergency response in event of a large earthquake will be crucial to minimizing the loss of life and disruption of lifeline systems in Puerto Rico. The ShakeMap system (Wald et al, 2004) developed by the USGS to rapidly display and disseminate information about the geographical distribution of ground shaking (and hence potential damage) following a large earthquake has proven to be a vital tool for post earthquake emergency response efforts, and is being adopted/emulated in various seismically active regions worldwide. Implementing a robust ShakeMap system is among the top priorities of the Puerto Rico Seismic Network. However, the ultimate effectiveness of ShakeMap in post- earthquake response depends not only on its rapid availability, but also on the effective use of the information it provides. We developed ShakeMap scenarios of a suite of damaging historical and probable earthquakes that severely impact San Juan, Ponce, and Mayagüez, the 3 largest cities in Puerto Rico. Earthquake source parameters were obtained from McCann and Mercado (1998); and Huérfano (2004). For historical earthquakes that generated tsunamis, tsunami inundation maps were generated using the TIME method (Shuto, 1991). The ShakeMap ground shaking maps were presented to local and regional governmental and emergency response agencies at the 2007 Annual conference of the Puerto Rico Emergency Management and Disaster Administration in San Juan, PR, and at numerous other emergency management talks and training sessions. Economic losses are estimated using the ShakeMap scenario ground motions (Saffar, 2007). The calibration tasks necessary in generating these scenarios (developing Vs30 maps, attenuation relationships) complement the on-going efforts of the Puerto Rico Seismic Network to generate ShakeMaps in real-time.

The numerical simulation study of the dynamic evolutionary processes in an earthquake cycle on the Longmen Shan Fault

NASA Astrophysics Data System (ADS)

Tao, Wei; Shen, Zheng-Kang; Zhang, Yong

2016-04-01

The Longmen Shan, located in the conjunction of the eastern margin the Tibet plateau and Sichuan basin, is a typical area for studying the deformation pattern of the Tibet plateau. Following the 2008 Mw 7.9 Wenchuan earthquake (WE) rupturing the Longmen Shan Fault (LSF), a great deal of observations and studies on geology, geophysics, and geodesy have been carried out for this region, with results published successively in recent years. Using the 2D viscoelastic finite element model, introducing the rate-state friction law to the fault, this thesis makes modeling of the earthquake recurrence process and the dynamic evolutionary processes in an earthquake cycle of 10 thousand years. By analyzing the displacement, velocity, stresses, strain energy and strain energy increment fields, this work obtains the following conclusions: (1) The maximum coseismic displacement on the fault is on the surface, and the damage on the hanging wall is much more serious than that on the foot wall of the fault. If the detachment layer is absent, the coseismic displacement would be smaller and the relative displacement between the hanging wall and foot wall would also be smaller. (2) In every stage of the earthquake cycle, the velocities (especially the vertical velocities) on the hanging wall of the fault are larger than that on the food wall, and the values and the distribution patterns of the velocity fields are similar. While in the locking stage prior to the earthquake, the velocities in crust and the relative velocities between hanging wall and foot wall decrease. For the model without the detachment layer, the velocities in crust in the post-seismic stage is much larger than those in other stages. (3) The maximum principle stress and the maximum shear stress concentrate around the joint of the fault and detachment layer, therefore the earthquake would nucleate and start here. (4) The strain density distribution patterns in stages of the earthquake cycle are similar. There are two concentration areas in the model, one is located in the mid and upper crust on the hanging wall where the strain energy could be released by permanent deformation like folding, and the other lies in the deep part of the fault where the strain energy could be released by earthquakes. (5) The whole earthquake dynamic process could be clearly reflected by the evolutions of the strain energy increments on the stages of the earthquake cycle. In the inter-seismic period, the strain energy accumulates relatively slowly; prior to the earthquake, the fault is locking and the strain energy accumulates fast, and some of the strain energy is released on the upper crust on the hanging wall of the fault. In coseismic stage, the strain energy is released fast along the fault. In the poseismic stage, the slow accumulation process of strain recovers rapidly as that in the inerseismic period in around one hundred years. The simulation study in this thesis would help better understand the earthquake dynamic process.

Seismic Rehabilitation of RC Frames by Using Steel Panels

NASA Astrophysics Data System (ADS)

Mowrtage, Waiel

2008-07-01

Every major earthquake in Turkey causes a large number of building suffer moderate damage due to poor construction. If a proper and fast retrofit is not applied, the aftershocks, which may sometimes come days or weeks after the main shock, can push a moderately damaged building into a major damage or even total collapse. This paper presents a practical retrofit method for moderately damaged buildings, which increases the seismic performance of the structural system by reducing the displacement demand. Fabricated steel panels are used for the retrofit. They are light-weight, easy to handle, and can be constructed very quickly. Moreover, they are cheap, and do not need formwork or skilled workers. They can be designed to compensate for the stiffness and strength degradation, and to fit easily inside a moderately damaged reinforced concrete frame. To test the concept, a half-scale, single-story 3D reinforced concrete frame specimen was constructed at the shake-table laboratories of the Kandilli Observatory and Earthquake Research Institute of Bogazici University, and subjected to recorded real earthquake base accelerations. The amplitudes of base accelerations were increased until a moderate damage level is reached. Then, the damaged RC frames was retrofitted by means of steel panels and tested under the same earthquake. The seismic performance of the specimen before and after the retrofit was evaluated using FEMA356 standards, and the results were compared in terms of stiffness, strength, and deformability. The results have confirmed effectiveness of the proposed retrofit scheme.

Comparison of Earthquake Damage Patterns and Shallow-Depth Vs Structure Across the Napa Valley, Inferred From Multichannel Analysis of Surface Waves (MASW) and Multichannel Analysis of Love Waves (MALW) Modeling of Basin-Wide Seismic Profiles

NASA Astrophysics Data System (ADS)

Chan, J. H.; Catchings, R.; Strayer, L. M.; Goldman, M.; Criley, C.; Sickler, R. R.; Boatwright, J.

2017-12-01

We conducted an active-source seismic investigation across the Napa Valley (Napa Valley Seismic Investigation-16) in September of 2016 consisting of two basin-wide seismic profiles; one profile was 20 km long and N-S-trending (338°), and the other 15 km long and E-W-trending (80°) (see Catchings et al., 2017). Data from the NVSI-16 seismic investigation were recorded using a total of 666 vertical- and horizontal-component seismographs, spaced 100 m apart on both seismic profiles. Seismic sources were generated by a total of 36 buried explosions spaced 1 km apart. The two seismic profiles intersected in downtown Napa, where a large number of buildings were red-tagged by the City following the 24 August 2014 Mw 6.0 South Napa earthquake. From the recorded Rayleigh and Love waves, we developed 2-Dimensional S-wave velocity models to depths of about 0.5 km using the multichannel analysis of surface waves (MASW) method. Our MASW (Rayleigh) and MALW (Love) models show two prominent low-velocity (Vs = 350 to 1300 m/s) sub-basins that were also previously identified from gravity studies (Langenheim et al., 2010). These basins trend N-W and also coincide with the locations of more than 1500 red- and yellow-tagged buildings within the City of Napa that were tagged after the 2014 South Napa earthquake. The observed correlation between low-Vs, deep basins, and the red-and yellow-tagged buildings in Napa suggests similar large-scale seismic investigations can be performed. These correlations provide insights into the likely locations of significant structural damage resulting from future earthquakes that occur adjacent to or within sedimentary basins.

Site Effects Study In Athens (greece) Using The 7th September 1999 Earthquake Aftershock Sequence

NASA Astrophysics Data System (ADS)

Serpetsidaki, A.; Sokos, E.

On 7 September 1999 at 11:56:50 GMT, an earthquake of Mw=5.9 occurred at Athens capital of Greece. The epicenter was located in the Northwest area of Parnitha Moun- tain at 18km distance from the city centre. This earthquake was one of the most de- structive in Greece during the modern times. The intensity of the earthquake reached IX in the Northwest territories of the city and caused the death of 143 people and seri- ous structural damage in many buildings. On the 13th of September the Seismological Laboratory of Patras University, installed a seismic network of 30 stations in order to observe the evolution of the aftershock sequence. This temporary seismic network remained in the area of Attika for 50 days and recorded a significant part of the af- tershock sequence. In this paper we use the high quality recordings of this network to investigate the influence of the surface geology to the seismic motion, on sites within the epicentral area, which suffered the most during this earthquake. We applied the horizontal-to-vertical (H/V) spectral ratio method on noise and on earthquake records and the obtained results exhibit very good agreement. Finally we compare the results with the geological conditions of the study area and the damage distribution. Most of the obtained amplification levels were low with an exemption in the site of Ano Liosia were a significant amount of damage was observed and the results indicate that the earthquake motion was amplified four times. Based on the above we conclude that the damages in the city of Athens were due to source effects rather than site effects.

The 7.9 Denali Fault Earthquake: Damage to Structures and Lifelines

NASA Astrophysics Data System (ADS)

Cox, T.; Hreinsdöttir, S.; Larsen, C.; Estes, S.

2002-12-01

In the early afternoon of Sunday, November 3rd, the residents of many interior Alaska towns were shaken up by a magnitude 7.9 earthquake. The shaking lasted an average of three minutes and when it stopped, nearly 300 km of the Denali Fault had ruptured. In the hours that followed, the Alaska Earthquake Information Center (AEIC) fielded reports of structural damage from Cantwell to Tok and other earthquake effects as far away as Louisiana. Upon investigation, the most severe effects were found in the village of Mentasta where basic utilities were interrupted and the school and several houses suffered major damage. Almost 3000 reports submitted to a community internet intensity map show a maximum Mercalli intensity VIII along the eastern end of the rupture area. The Richardson and Parks Highways, two main north-south thoroughfares in Alaska, both buckled and split as a result of the fault rupture. Traffic was stopped for a few hours while repairs were made. Between the Richardson Highway the Tok Cutoff, a section of the Glenn Highway that connects Tok and Glennallen, the maximum offsets on the Denali Fault were observed. Designed to withstand a magnitude 8.5 earthquake at the Denali Fault crossing, the 800-mile long Trans-Alaska Pipeline suffered relatively minor damage. According to Alyeska Pipeline Service Company press releases, the pipeline was shut down shortly after the earthquake occurred. Repairs to pipeline supports and engineering evaluations began immediately thereafter, and oil began flowing through the pipeline Thursday, November 7th . Through it all, the AEIC has collected and archived many photographs, emails, and eyewitness accounts of those who experienced the destruction firsthand. We will detail the effects that the M7.9 Denali Fault earthquake had from near and far.

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.

Pattern recognition approach to the subsequent event of damaging earthquakes in Italy

NASA Astrophysics Data System (ADS)

Gentili, S.; Di Giovambattista, R.

2017-05-01

In this study, we investigate the occurrence of large aftershocks following the most significant earthquakes that occurred in Italy after 1980. In accordance with previous studies (Vorobieva and Panza, 1993; Vorobieva, 1999), we group clusters associated with mainshocks into two categories: ;type A; if, given a main shock of magnitude M, the subsequent strongest earthquake in the cluster has magnitude ≥M - 1 or type B otherwise. In this paper, we apply a pattern recognition approach using statistical features to foresee the class of the analysed clusters. The classification of the two categories is based on some features of the time, space, and magnitude distribution of the aftershocks. Specifically, we analyse the temporal evolution of the radiated energy at different elapsed times after the mainshock, the spatio-temporal evolution of the aftershocks occurring within a few days, and the probability of a strong earthquake. An attempt is made to classify the studied region into smaller seismic zones with a prevalence of type A and B clusters. We demonstrate that the two types of clusters have distinct preferred geographic locations inside the Italian territory that likely reflected key properties of the deforming regions, different crustal domains and faulting style. We use decision trees as classifiers of single features to characterize the features depending on the cluster type. The performance of the classification is tested by the Leave-One-Out method. The analysis is performed on different time-spans after the mainshock to simulate the dependence of the accuracy on the information available as data increased over a longer period with increasing time after the mainshock.

Evaluating Post-Earthquake Building Safety Using Economical MEMS Seismometers

PubMed Central

Yin, Ren-Cheng

2018-01-01

The earthquake early warning (EEW)-research group at National Taiwan University has been developing a microelectromechanical system-based accelerometer called “P-Alert”, designed for issuing EEWs. The main advantage of P-Alert is that it is a relatively economical seismometer. However, because of the expensive nature of commercial hardware for structural health monitoring (SHM) systems, the application of SHM to buildings remains limited. To determine the performance of P-Alert for evaluating post-earthquake building safety, we conducted a series of steel-frame shaking table tests with incremental damage. We used the fragility curves of different damage levels and the interstory drift ratios (calculated by the measured acceleration of each story using double integration and a filter) to gauge the potential damage levels. We concluded that the acceptable detection of damage for an entire building is possible. With improvements to the synchronization of the P-Alert sensors, we also anticipate a damage localization feature for the stories of a building. PMID:29734736

Evaluating Post-Earthquake Building Safety Using Economical MEMS Seismometers.

PubMed

Hsu, Ting-Yu; Yin, Ren-Cheng; Wu, Yih-Min

2018-05-05

The earthquake early warning (EEW)-research group at National Taiwan University has been developing a microelectromechanical system-based accelerometer called “P-Alert”, designed for issuing EEWs. The main advantage of P-Alert is that it is a relatively economical seismometer. However, because of the expensive nature of commercial hardware for structural health monitoring (SHM) systems, the application of SHM to buildings remains limited. To determine the performance of P-Alert for evaluating post-earthquake building safety, we conducted a series of steel-frame shaking table tests with incremental damage. We used the fragility curves of different damage levels and the interstory drift ratios (calculated by the measured acceleration of each story using double integration and a filter) to gauge the potential damage levels. We concluded that the acceptable detection of damage for an entire building is possible. With improvements to the synchronization of the P-Alert sensors, we also anticipate a damage localization feature for the stories of a building.

Damage From the Nahrin, Afghanistan, Earthquake of 25 March, 2002

NASA Astrophysics Data System (ADS)

Madden, C. L.; Yeats, R. S.

2002-12-01

On 25 March, 2002, a destructive earthquake of mb = 6.1 struck the city of Nahrin and nearby villages in Baghlan Province in northeastern Afghanistan. The earthquake occurred on a southeast-dipping reverse fault that parallels the linear northeast-trending range front of the Hindu Kush Mountains, east of Nahrin. Field reconnaissance showed no disturbance of the ground by surface rupture, liquefaction, or lateral spreading, and virtually no evidence of landsliding or rockfall. United Nations and Afghan authorities estimate the death toll from the earthquake to be over 2000, with about 20,000 families impacted by the earthquake. We conducted a survey of damage in 68 villages affected by the earthquake and found that areas within 25 km of the epicenter experienced modified Mercalli intensities of between VI and VII. Shaking intensities were strong enough to cause complete building collapse in many villages. Site conditions were an important factor in the distribution of damage in the Nahrin area. Houses built on the narrow crests of ridges eroded in loess suffered major damage due to the focusing of near-surface seismic waves on ridge-tops. Houses on low fluvial terraces along the Nahrin River also suffered major damage, likely due to their close proximity to the water table. Structures built on metamorphic bedrock and alluvial fans along the range front of the Hindu Kush Mountains or on high terraces along the Nahrin River suffered comparatively less damage. Building failure was predominantly caused by the mud-block construction, characteristic of much of Afghanistan and adjacent countries. Most houses are built of mud blocks made from reworked loess, which contains a relatively low percentage of clay. The walls contain no bracing against lateral shear, and wall corners are not tied together, leading to failure at corners and roof collapse. In several villages, mosques were constructed to a higher standard and suffered significantly less damage than surrounding mud structures. The mosques often had concrete foundations and structural supports tied to the foundations. Had houses been built to the same standards as most mosques, loss of life would have been greatly reduced.

Quantitative Study of Vulnerability / Damage Curves in South Africa

NASA Astrophysics Data System (ADS)

Pule, Tebogo

2014-05-01

Southern Africa is considered a stable continental region in spite of several cases of reported earthquakes, which caused considerable damage and casualties particularly in the mining industry. Most buildings and structures in South Africa are not designed to resist any intensity of earthquake and most architects, engineers and builders in the country do not consider seismic resistance as a design requirement. This is mainly because the region has not experienced any large and serious destructive earthquake in recent years. The most destructive earthquake recorded in South Africa is the Ceres earthquake of 1969. The earthquake with a magnitude of 6.3 occurred on September 29, 1969 in the Ceres-Tulbagh region of the Western Cape Province about 100 km northeast of Cape Town. Serious damage occurred to certain buildings in the area (amounting to a total of U.S. 24 million). The structural damage varied from almost total destruction of old and poorly constructed buildings to large cracks in the better-built ones, twelve people were killed and many more were injured. Another event that caused severe damage to infrastructure occurred on March 9, 2005 at Stilfontein near Klerksdorp. It is known that up to 40 or more tremors are recorded monthly in Southern Africa, the locations are predominantly in the places surrounding the gold mining areas with many events around the Carletonville and Klerksdorp areas. Recent years have seen at least four mining induced tremors causing significant damage (Welkom 1976, Klerksdorp 1977, Welkom 1989 and Carletonville 1992). Such events show that it is very necessary to take seismic events into account in the design of any infrastructure. Assessing and understanding the risk facing the South African cities as a result of major seismic activity has been paid little attention. The main focus of this study is to use results of a deterministic hazard assessment to develop the most suitable damage curves for twelve of the most common building classes in four of the major cities in South Africa, namely, Johannesburg, Cape Town, Durban and Port Elizabeth.

Urban seismic risk assessment: statistical repair cost data and probable structural losses based on damage scenario—correlation analysis

NASA Astrophysics Data System (ADS)

Eleftheriadou, Anastasia K.; Baltzopoulou, Aikaterini D.; Karabinis, Athanasios I.

2016-06-01

The current seismic risk assessment is based on two discrete approaches, actual and probable, validating afterwards the produced results. In the first part of this research, the seismic risk is evaluated from the available data regarding the mean statistical repair/strengthening or replacement cost for the total number of damaged structures (180,427 buildings) after the 7/9/1999 Parnitha (Athens) earthquake. The actual evaluated seismic risk is afterwards compared to the estimated probable structural losses, which is presented in the second part of the paper, based on a damage scenario in the referring earthquake. The applied damage scenario is based on recently developed damage probability matrices (DPMs) from Athens (Greece) damage database. The seismic risk estimation refers to 750,085 buildings situated in the extended urban region of Athens. The building exposure is categorized in five typical structural types and represents 18.80 % of the entire building stock in Greece. The last information is provided by the National Statistics Service of Greece (NSSG) according to the 2000-2001 census. The seismic input is characterized by the ratio, a g/ a o, where a g is the regional peak ground acceleration (PGA) which is evaluated from the earlier estimated research macroseismic intensities, and a o is the PGA according to the hazard map of the 2003 Greek Seismic Code. Finally, the collected investigated financial data derived from different National Services responsible for the post-earthquake crisis management concerning the repair/strengthening or replacement costs or other categories of costs for the rehabilitation of earthquake victims (construction and function of settlements for earthquake homeless, rent supports, demolitions, shorings) are used to determine the final total seismic risk factor.

Examining Communities at Risk: Physical and Socioeconomic Impacts of an Earthquake Scenario on the Hayward Fault (The HayWired Scenario)

NASA Astrophysics Data System (ADS)

Dinitz, L.; Wein, A. M.; Johnson, L. A.; Jones, J. L.

2015-12-01

This research led by the U.S. Geological Survey aims to inform and stimulate the development of plans and policies in disaster management and hazard mitigation that will help improve the capacity of residents, businesses and communities to rebound from disasters. As was evidenced in the 1994 Northridge earthquake, "ghost towns" emerged in neighborhoods with high concentrations of damaged rental housing. Also, rental properties that served predominantly lower income households had more difficulty financing repairs which led to blight and other long-term community recovery challenges. Our approach is to develop a framework for identifying and spatially analyzing communities at risk of long-term displacement and recovery challenges for an earthquake scenario. The HayWired scenario postulates a M7.05 earthquake on the Hayward Fault in the San Francisco Bay Area with surface fault rupture, liquefaction, landslides, and fires, as well as subsequent aftershocks. The analytical framework relies on the literature and prior disaster experience to identify and systematically combine physical and socioeconomic impacts of the earthquake sequence with pre-existing socioeconomic conditions to identify areas where housing and building damage, lifeline service disruption, and socioeconomic challenges intersect and can potentially lead to long-term displacements of people, businesses, and jobs. Hazus analyses estimate $46 billion in building damage from the HayWired main shock, which increases by 10-25% due to aftershocks. Heavy damage to large apartment buildings exceeds many other housing types, and preliminary analyses identify neighborhoods where these damage concentrations also intersect with concentrations of low income households. Also, in some counties, the estimated population displaced from severely damaged housing far exceeds the number of vacant housing units, which means residents may be forced to move well away from former neighborhoods and even outside the region altogether.

75 FR 30004 - Notice of Intent To Prepare an Environmental Impact Statement for the Elliott Bay Seawall Project...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-05-28

... (seawall) provides protection to Seattle's downtown waterfront from storm waves and the erosive tidal... associated with coastal storms, shoreline erosion and earthquake damage that could lead to failure of the... evaluate the seawall from a coastal storm and earthquake damage reduction perspective; the seawall is the...

Seismic maps foster landmark legislation

USGS Publications Warehouse

Borcherdt, Roger D.; Brown, Robert B.; Page, Robert A.; Wentworth, Carl M.; Hendley, James W.

1995-01-01

When a powerful earthquake strikes an urban region, damage concentrates not only near the quake's source. Damage can also occur many miles from the source in areas of soft ground. In recent years, scientists have developed ways to identify and map these areas of high seismic hazard. This advance has spurred pioneering legislation to reduce earthquake losses in areas of greatest hazard.

Geotechnical aspects in the epicentral region of the 2011, Mw5.8 Mineral, Virginia earthquake

USGS Publications Warehouse

Green, Russell A.; Lasley, Samuel; Carter, Mark W.; Munsey, Jeffrey W.; Maurer, Brett W.; Tuttle, Martitia P.

2015-01-01

A reconnaissance team documented the geotechnical and geological aspects in the epicentral region of the Mw (moment magnitude) 5.8 Mineral, Virginia (USA), earthquake of 23 August 2011. Tectonically and seismically induced ground deformations, evidence of liquefaction, rock slides, river bank slumps, ground subsidence, performance of earthen dams, damage to public infrastructure and lifelines, and other effects of the earthquake were documented. This moderate earthquake provided the rare opportunity to collect data to help assess current geoengineering practices in the region, as well as to assess seismic performance of the aging infrastructure in the region. Ground failures included two marginal liquefaction sites, a river bank slump, four minor rockfalls, and a ~4-m-wide, ~12-m-long, ~0.3-m-deep subsidence on a residential property. Damage to lifelines included subsidence of the approaches for a bridge and a water main break to a heavily corroded, 5-cm-diameter valve in Mineral, Virginia. Observed damage to dams, landfills, and public-use properties included a small, shallow slide in the temporary (“working”) clay cap of the county landfill, damage to two earthen dams (one in the epicentral region and one further away near Bedford, Virginia), and substantial structural damage to two public school buildings.

Strain-dependent Damage Evolution and Velocity Reduction in Fault Zones Induced by Earthquake Rupture

NASA Astrophysics Data System (ADS)

Zhong, J.; Duan, B.

2009-12-01

Low-velocity fault zones (LVFZs) with reduced seismic velocities relative to the surrounding wall rocks are widely observed around active faults. The presence of such a zone will affect rupture propagation, near-field ground motion, and off-fault damage in subsequent earth-quakes. In this study, we quantify the reduction of seismic velocities caused by dynamic rup-ture on a 2D planar fault surrounded by a low-velocity fault zone. First, we implement the damage rheology (Lyakhovsky et al. 1997) in EQdyna (Duan and Oglesby 2006), an explicit dynamic finite element code. We further extend this damage rheology model to include the dependence of strains on crack density. Then, we quantify off-fault continuum damage distribution and velocity reduction induced by earthquake rupture with the presence of a preexisting LVFZ. We find that the presence of a LVFZ affects the tempo-spatial distribu-tions of off-fault damage. Because lack of constraint in some damage parameters, we further investigate the relationship between velocity reduction and these damage prameters by a large suite of numerical simulations. Slip velocity, slip, and near-field ground motions computed from damage rheology are also compared with those from off-fault elastic or elastoplastic responses. We find that the reduction in elastic moduli during dynamic rupture has profound impact on these quantities.

Local amplification of seismic waves from the Denali earthquake and damaging seiches in Lake Union, Seattle, Washington

USGS Publications Warehouse

Barberopoulou, A.; Qamar, A.; Pratt, T.L.; Creager, K.C.; Steele, W.P.

2004-01-01

The Mw7.9 Denali, Alaska earthquake of 3 November, 2002, caused minor damage to at least 20 houseboats in Seattle, Washington by initiating water waves in Lake Union. These water waves were likely initiated during the large amplitude seismic surface waves from this earthquake. Maps of spectral amplification recorded during the Denali earthquake on the Pacific Northwest Seismic Network (PNSN) strong-motion instruments show substantially increased shear and surface wave amplitudes coincident with the Seattle sedimentary basin. Because Lake Union is situated on the Seattle basin, the size of the water waves may have been increased by local amplification of the seismic waves by the basin. Complete hazard assessments require understanding the causes of these water waves during future earthquakes. Copyright 2004 by the American Geophysical Union.

Reactivated faulting near Cushing, Oklahoma: Increased potential for a triggered earthquake in an area of United States strategic infrastructure

USGS Publications Warehouse

McNamara, Daniel E.; Hayes, Gavin; Benz, Harley M.; Williams, Robert; McMahon, Nicole D; Aster, R.C.; Holland, Austin F.; Sickbert, T; Herrmann, Robert B.; Briggs, Richard; Smoczyk, Gregory M.; Bergman, Eric; Earle, Paul S.

2015-01-01

In October 2014 two moderate-sized earthquakes (Mw 4.0 and 4.3) struck south of Cushing, Oklahoma, below the largest crude oil storage facility in the world. Combined analysis of the spatial distribution of earthquakes and regional moment tensor focal mechanisms indicate reactivation of a subsurface unnamed and unmapped left-lateral strike-slip fault. Coulomb failure stress change calculations using the relocated seismicity and slip distribution determined from regional moment tensors, allow for the possibility that the Wilzetta-Whitetail fault zone south of Cushing, Oklahoma, could produce a large, damaging earthquake comparable to the 2011 Prague event. Resultant very strong shaking levels (MMI VII) in the epicentral region present the possibility of this potential earthquake causing moderate to heavy damage to national strategic infrastructure and local communities.

Geomorphic and geologic controls of geohazards induced by Nepal's 2015 Gorkha earthquake.

PubMed

Kargel, J S; Leonard, G J; Shugar, D H; Haritashya, U K; Bevington, A; Fielding, E J; Fujita, K; Geertsema, M; Miles, E S; Steiner, J; Anderson, E; Bajracharya, S; Bawden, G W; Breashears, D F; Byers, A; Collins, B; Dhital, M R; Donnellan, A; Evans, T L; Geai, M L; Glasscoe, M T; Green, D; Gurung, D R; Heijenk, R; Hilborn, A; Hudnut, K; Huyck, C; Immerzeel, W W; Liming, Jiang; Jibson, R; Kääb, A; Khanal, N R; Kirschbaum, D; Kraaijenbrink, P D A; Lamsal, D; Shiyin, Liu; Mingyang, Lv; McKinney, D; Nahirnick, N K; Zhuotong, Nan; Ojha, S; Olsenholler, J; Painter, T H; Pleasants, M; Pratima, K C; Yuan, Q I; Raup, B H; Regmi, D; Rounce, D R; Sakai, A; Donghui, Shangguan; Shea, J M; Shrestha, A B; Shukla, A; Stumm, D; van der Kooij, M; Voss, K; Xin, Wang; Weihs, B; Wolfe, D; Lizong, Wu; Xiaojun, Yao; Yoder, M R; Young, N

2016-01-08

The Gorkha earthquake (magnitude 7.8) on 25 April 2015 and later aftershocks struck South Asia, killing ~9000 people and damaging a large region. Supported by a large campaign of responsive satellite data acquisitions over the earthquake disaster zone, our team undertook a satellite image survey of the earthquakes' induced geohazards in Nepal and China and an assessment of the geomorphic, tectonic, and lithologic controls on quake-induced landslides. Timely analysis and communication aided response and recovery and informed decision-makers. We mapped 4312 coseismic and postseismic landslides. We also surveyed 491 glacier lakes for earthquake damage but found only nine landslide-impacted lakes and no visible satellite evidence of outbursts. Landslide densities correlate with slope, peak ground acceleration, surface downdrop, and specific metamorphic lithologies and large plutonic intrusions. Copyright © 2016, American Association for the Advancement of Science.

Geomorphic and Geologic Controls of Geohazards induced by Nepal's 2015 Gorkha Earthquake

NASA Technical Reports Server (NTRS)

Kargel, J. S.; Leonard, G. J.; Shugar, D. H.; Haritashya, U.K.; Bevington, A.; Fielding, E. J.; Fujita, K.; Geertsema, M.; Miles, E. S.; Steiner, J.;

Assessment of Seismic Damage on The Exist Buildings Using Fuzzy Logic

NASA Astrophysics Data System (ADS)

Pınar, USTA; Nihat, MOROVA; EVCİ, Ahmet; ERGÜN, Serap

2018-01-01

Earthquake as a natural disaster could damage the lives of many people and buildings all over the world. These is micvulnerability of the buildings needs to be evaluated. Accurate evaluation of damage sustained by buildings during natural disaster events is critical to determine the buildings safety and their suitability for future occupancy. The earthquake is one of the disasters that structures face the most. There fore, there is a need to evaluate seismic damage and vulnerability of the buildings to protect them. These days fuzzy systems have been widely used in different fields of science because of its simpli city and efficiency. Fuzzy logic provides a suitable framework for reasoning, deduction, and decision making in fuzzy conditions. In this paper, studies on earthquake hazard evaluation of buildings by fuzzy logic modeling concepts in the literature have been investigated and evaluated, as a whole.

Seismic risk maps

USGS Publications Warehouse

Perkins, David M.; Mallis, Robert

1974-01-01

What is the possibility that an earthquake will occur near you? Have you ever wondered what the chances were that an earthquake could affect you at home or at work? Perhaps you are planning to move to a part of the country subject to frequent earthquakes. How do you determine the relative likelihood that an earthquake will cause damage at a particular place.  

A comparison of socio-economic loss analysis from the 2013 Haiyan Typhoon and Bohol Earthquake events in the Philippines in near real-time

NASA Astrophysics Data System (ADS)

Daniell, James; Mühr, Bernhard; Kunz-Plapp, Tina; Brink, Susan A.; Kunz, Michael; Khazai, Bijan; Wenzel, Friedemann

2014-05-01

In the aftermath of a disaster, the extent of the socioeconomic loss (fatalities, homelessness and economic losses) is often not known and it may take days before a reasonable estimate is known. Using the technique of socio-economic fragility functions developed (Daniell, 2014) using a regression of socio-economic indicators through time against historical empirical loss vs. intensity data, a first estimate can be established. With more information from the region as the disaster unfolds, a more detailed estimate can be provided via a calibration of the initial loss estimate parameters. In 2013, two main disasters hit the Philippines; the Bohol earthquake in October and the Haiyan typhoon in November. Although both disasters were contrasting and hit different regions, the same generalised methodology was used for initial rapid estimates and then the updating of the disaster loss estimate through time. The CEDIM Forensic Disaster Analysis Group of KIT and GFZ produced 6 reports for Bohol and 2 reports for Haiyan detailing various aspects of the disasters from the losses to building damage, the socioeconomic profile and also the social networking and disaster response. This study focusses on the loss analysis undertaken. The following technique was used:- 1. A regression of historical earthquake and typhoon losses for the Philippines was examined using the CATDAT Damaging Earthquakes Database, and various Philippines databases respectively. 2. The historical intensity impact of the examined events were placed in a GIS environment in order to allow correlation with the population and capital stock database from 1900-2013 to create a loss function. The modified human development index from 1900-2013 was also used to also calibrate events through time. 3. The earthquake intensity and the wind speed intensity was used from the 2013 events as well as the 2013 capital stock and population in order to calculate the number of fatalities (except in Haiyan), homeless and economic losses. 4. After the initial estimate, damage patterns were examined and the loss estimates calibrated. The economic loss estimates of 9.5 billion USD capital stock and 4.1 billion USD GDP costs and the estimate of 2.1 million long term homeless from the Typhoon Haiyan event from the initial model proved very accurate with around the same values coming from reports around a month after the event. For the Bohol earthquake, the economic loss estimate was reasonable (around 100 million USD), however, the number of fatalities was slightly underestimated given the intensity field being underestimated and due to the number of landslide and other deaths (heart attacks etc.) in the first day. As the damage estimates were reported on post-disaster over the next days, the fatality function was calibrated and produced results closer to 200 deaths. Such parsimonious modelling in the aftermath of a disaster and socioeconomic profiling of the disaster area can prove useful to relief agencies and governments as well as those on the ground giving a first estimate of the extent of the damage and the models will as such continue to be developed in the course of FDA. Daniell J.E. (2014) The development of socio-economic fragility functions for use in worldwide rapid earthquake loss estimation procedures, Ph.D. Thesis (in publishing), Karlsruhe Institute of Technology, Karlsruhe, Germany.

UCERF3: A new earthquake forecast for California's complex fault system

USGS Publications Warehouse

Field, Edward H.; ,

2015-01-01

With innovations, fresh data, and lessons learned from recent earthquakes, scientists have developed a new earthquake forecast model for California, a region under constant threat from potentially damaging events. The new model, referred to as the third Uniform California Earthquake Rupture Forecast, or "UCERF" (http://www.WGCEP.org/UCERF3), provides authoritative estimates of the magnitude, location, and likelihood of earthquake fault rupture throughout the state. Overall the results confirm previous findings, but with some significant changes because of model improvements. For example, compared to the previous forecast (Uniform California Earthquake Rupture Forecast 2), the likelihood of moderate-sized earthquakes (magnitude 6.5 to 7.5) is lower, whereas that of larger events is higher. This is because of the inclusion of multifault ruptures, where earthquakes are no longer confined to separate, individual faults, but can occasionally rupture multiple faults simultaneously. The public-safety implications of this and other model improvements depend on several factors, including site location and type of structure (for example, family dwelling compared to a long-span bridge). Building codes, earthquake insurance products, emergency plans, and other risk-mitigation efforts will be updated accordingly. This model also serves as a reminder that damaging earthquakes are inevitable for California. Fortunately, there are many simple steps residents can take to protect lives and property.

Impact of the Christchurch earthquakes on hospital staff.

PubMed

Tovaranonte, Pleayo; Cawood, Tom J

2013-06-01

On September 4, 2010 a major earthquake caused widespread damage, but no loss of life, to Christchurch city and surrounding areas. There were numerous aftershocks, including on February 22, 2011 which, in contrast, caused substantial loss of life and major damage to the city. The research aim was to assess how these two earthquakes affected the staff in the General Medicine Department at Christchurch Hospital. Problem To date there have been no published data assessing the impact of this type of natural disaster on hospital staff in Australasia. A questionnaire that examined seven domains (demographics, personal impact, psychological impact, emotional impact, impact on care for patients, work impact, and coping strategies) was handed out to General Medicine staff and students nine days after the September 2010 earthquake and 14 days after the February 2011 earthquake. Response rates were ≥ 99%. Sixty percent of responders were <30 years of age, and approximately 60% were female. Families of eight percent and 35% had to move to another place due to the September and February earthquakes, respectively. A fifth to a third of people had to find an alternative route of transport to get to work but only eight percent to 18% took time off work. Financial impact was more severe following the February earthquake, with 46% reporting damage of >NZ $1,000, compared with 15% following the September earthquake (P < .001). Significantly more people felt upset about the situation following the February earthquake than the September earthquake (42% vs 69%, P < .001). Almost a quarter thought that quality of patient care was affected in some way following the September earthquake but this rose to 53% after the February earthquake (12/53 vs 45/85, P < .001). Half believed that discharges were delayed following the September earthquake but this dropped significantly to 15% following the February earthquake (27/53 vs 13/62, P < .001). This survey provides a measure of the result of two major but contrasting Christchurch earthquakes upon General Medicine hospital staff. The effect was widespread with minor financial impact during the first but much more during the second earthquake. Moderate psychological impact was experienced in both earthquakes. This data may be useful to help prepare plans for future natural disasters. .

A Hybrid Tsunami Risk Model for Japan

NASA Astrophysics Data System (ADS)

Haseemkunju, A. V.; Smith, D. F.; Khater, M.; Khemici, O.; Betov, B.; Scott, J.

2014-12-01

Around the margins of the Pacific Ocean, denser oceanic plates slipping under continental plates cause subduction earthquakes generating large tsunami waves. The subducting Pacific and Philippine Sea plates create damaging interplate earthquakes followed by huge tsunami waves. It was a rupture of the Japan Trench subduction zone (JTSZ) and the resultant M9.0 Tohoku-Oki earthquake that caused the unprecedented tsunami along the Pacific coast of Japan on March 11, 2011. EQECAT's Japan Earthquake model is a fully probabilistic model which includes a seismo-tectonic model describing the geometries, magnitudes, and frequencies of all potential earthquake events; a ground motion model; and a tsunami model. Within the much larger set of all modeled earthquake events, fault rupture parameters for about 24000 stochastic and 25 historical tsunamigenic earthquake events are defined to simulate tsunami footprints using the numerical tsunami model COMCOT. A hybrid approach using COMCOT simulated tsunami waves is used to generate inundation footprints, including the impact of tides and flood defenses. Modeled tsunami waves of major historical events are validated against observed data. Modeled tsunami flood depths on 30 m grids together with tsunami vulnerability and financial models are then used to estimate insured loss in Japan from the 2011 tsunami. The primary direct report of damage from the 2011 tsunami is in terms of the number of buildings damaged by municipality in the tsunami affected area. Modeled loss in Japan from the 2011 tsunami is proportional to the number of buildings damaged. A 1000-year return period map of tsunami waves shows high hazard along the west coast of southern Honshu, on the Pacific coast of Shikoku, and on the east coast of Kyushu, primarily associated with major earthquake events on the Nankai Trough subduction zone (NTSZ). The highest tsunami hazard of more than 20m is seen on the Sanriku coast in northern Honshu, associated with the JTSZ.

A Study on the Relationship between Disaster and Spectral Intensity

NASA Astrophysics Data System (ADS)

Yeh, Yeong-Tein; Kao, Ching-Yun

2010-05-01

Nowadays, the structural environment is becoming so complicated that an index, which can better assess earthquake damage than the originally defined intensity scale and PGA, is needed. Housner [1] suggested that spectral intensity (SI) can be a risk index of an earthquake. After Housner some earthquake engineers keep on exploring different period range of SI and its application [2-5]. The study of Matsumura [4] shows that SI is a better measure of earthquake intensity for a wide range of frequencies with a good correlation with damage than peak ground acceleration (adequate to structures with shorter natural period) and peak ground velocity (adequate to structures with longer natural period). Recently, Jean [6] investigated earthquake intensity attenuation law and site effect of strong ground motion using earthquake records in Taiwan area. Their results show that SI is a better earthquake damage index than PGA. This study enhanced the SI concept proposed by Jean [6]. The spectral intensity was separated into three periods, short period (acceleration controlled period), medium period (velocity controlled period), and long period (displacement controlled period). The average spectral intensity of short period, medium period, and long period can be an earthquake damage index of low-rise buildings, buildings of medium height, and high-rise buildings. Since average value of a certain data is meaningful when the data has a small variance, the start and end points of the three periods are calculated by statistical method so that the data at each period has minimum variance. Finally, the relationship between disaster and spectral intensity of 1999 Taiwan Chi-Chi earthquake was investigated in this study. [1] Housner, G. W. (1952). "Spectrum intensity of strong-motion earthquakes," in Proc. Sym. Earthq. Blast Eeff. on Stru., EERI, U.C.L.A.. [2] Hidalgo.P. and R. W.Clough (1974). "Earthquake simulator study of a reinforced concrete frame," Report UCB/EERC-74/13, EERC, University of California, Berkeley. [3] Kappos, A. J (1991). "Analytical prediction of the collpase earthquake for R. C. buildings: suggested methodology," Earthq. Eng. Stru. Dyn., 20, 2, pp. 167-176. [4] Matsumura, K. (1992). "On the intensity measure of strong motions related to structural failures," in Proceeding of 10 WCEE, 1, pp. 375-380. [5] Martinez-Rueda, J. E (1998). "Scaling procedure for natural accelerograms based on a system of spectrum intensity scales," Earthq. Spec., 14, 1,. [6] Jean, W. Y., Y. W. Chang, K. L. Wen, and C. H. Loh (2006). "Early estimation of seismic hazard for strong earthquakes in Taiwan," Natural Hazards, vol. 37, pp. 39-53.

Major Earthquakes of the Past Decade (2000-2010): A Comparative Review of Various Aspects of Management

PubMed Central

Kalantar Motamedi, Mohammad Hosein; Sagafinia, Masoud; Ebrahimi, Ali; Shams, Ehsan; Kalantar Motamedi, Mostafa

2012-01-01

Objectives: This article sought to review and compare data of major earthquakes of the past decade and their aftermath in order to compare the magnitude, death toll, type of injuries, management procedures, extent of destruction and effectiveness of relief efforts. Materials and Methods: A retrospective study of the various aspects of management and aftermath of 5 major earthquakes of the past decade (2000–2010) was undertaken. This included earthquakes occurring in Bam Iran, Sichuan China, Port-au-Prince Haiti, Kashmir Pakistan and Ica Peru. A literature search was done via computer of published articles (indexed in Pubmed). The issues assessed included: 1)Local magnitude,2)Type of building structure 3)Time of the earthquake (day/time/season), 4)Time to rescue, 5)Triage, Transfer, and Treatment 6) Distribution of casualties (dead/ injured), 7)Degree of city damage, 8)Degree of damage to health facilities, 9)Field hospital availability, 10)International aid, 11)Air transfer, 12) Telecommunication systems availability, 13) PTSD prevalence, 14) Most common injury and 15) Most common disease outbreak. Results: The Bam earthquake had the lowest (6.6 Richter’s) and the Sichuan earthquake had the greatest magnitude (8.0 Richter’s). Mortality in Haiti was 212,000 and it was the deadliest earthquake of the past decade. Collapse of heavy clay roofing structures was a major cause of death in Iran and Pakistan. Earthquakes occurring at night and nonworking days carried a high death toll. The time to rescue and treat was the lengthiest in Haiti (possibly contributing to the death to injured ratio). However, the worst dead to injured ratios were in Bam (51%) and in Pakistan (47%); the best ratio was in China (15%). Iran and Pakistan suffered the highest percentage of damage to the health facilities (90%). Field hospital availability, international aid and air transfer were important issues. Telecommunication systems were best in China and worst in Pakistan. PTSD prevalence was highest in Iran. Respiratory infection was the most common infection following all 5 earthquakes. Conclusions: Earthquake damage, death toll, managerial protocols etc. vary in different countries and are influenced by many factors including the hour the earthquake hits and the day of the week. Additionally, social, structural and geographic factors as well as the medical, governmental and NGO respondents are influential. Engineered residential construction remains to be of importance in reducing mortality in developing countries. It is essential that hospitals, fire departments and police stations, water, telephone and electrical facilities be made earthquake proof. PMID:24829886

Major earthquakes of the past decade (2000-2010): a comparative review of various aspects of management.

PubMed

Kalantar Motamedi, Mohammad Hosein; Sagafinia, Masoud; Ebrahimi, Ali; Shams, Ehsan; Kalantar Motamedi, Mostafa

2012-01-01

This article sought to review and compare data of major earthquakes of the past decade and their aftermath in order to compare the magnitude, death toll, type of injuries, management procedures, extent of destruction and effectiveness of relief efforts. A retrospective study of the various aspects of management and aftermath of 5 major earthquakes of the past decade (2000-2010) was undertaken. This included earthquakes occurring in Bam Iran, Sichuan China, Port-au-Prince Haiti, Kashmir Pakistan and Ica Peru. A literature search was done via computer of published articles (indexed in Pubmed). The issues assessed included: 1)Local magnitude,2)Type of building structure 3)Time of the earthquake (day/time/season), 4)Time to rescue, 5)Triage, Transfer, and Treatment 6) Distribution of casualties (dead/ injured), 7)Degree of city damage, 8)Degree of damage to health facilities, 9)Field hospital availability, 10)International aid, 11)Air transfer, 12) Telecommunication systems availability, 13) PTSD prevalence, 14) Most common injury and 15) Most common disease outbreak. The Bam earthquake had the lowest (6.6 Richter's) and the Sichuan earthquake had the greatest magnitude (8.0 Richter's). Mortality in Haiti was 212,000 and it was the deadliest earthquake of the past decade. Collapse of heavy clay roofing structures was a major cause of death in Iran and Pakistan. Earthquakes occurring at night and nonworking days carried a high death toll. The time to rescue and treat was the lengthiest in Haiti (possibly contributing to the death to injured ratio). However, the worst dead to injured ratios were in Bam (51%) and in Pakistan (47%); the best ratio was in China (15%). Iran and Pakistan suffered the highest percentage of damage to the health facilities (90%). Field hospital availability, international aid and air transfer were important issues. Telecommunication systems were best in China and worst in Pakistan. PTSD prevalence was highest in Iran. Respiratory infection was the most common infection following all 5 earthquakes. Earthquake damage, death toll, managerial protocols etc. vary in different countries and are influenced by many factors including the hour the earthquake hits and the day of the week. Additionally, social, structural and geographic factors as well as the medical, governmental and NGO respondents are influential. Engineered residential construction remains to be of importance in reducing mortality in developing countries. It is essential that hospitals, fire departments and police stations, water, telephone and electrical facilities be made earthquake proof.

The results of the Seismic Alert System of Mexico SASMEX, during the earthquakes of 7 and 19 of September 2017

NASA Astrophysics Data System (ADS)

Espinosa Aranda, J. M., Sr.; Cuellar Martinez, A.

2017-12-01

The Seismic Alert System of Mexico, SASMEX began in 1991, is integrated by the seismic alert system of Mexico City and the seismic alert system of Oaxaca. SASMEX has 97 seismic sensors which are distributed in the seismic regions of the Pacific coast and the South of the Trans-Mexican Volcanic Belt of states of Jalisco, Colima, Michoacán, Guerrero, Oaxaca and Puebla. The alert dissemination covers the cities of: Acapulco, Chilpancingo, Morelia, Puebla, Oaxaca, Toluca and Mexico City, reaching the earthquake warnings to more than 25 millions of people. SASMEX has detected correctly more than 5600 earthquakes and warned 156. Mexico City has different alert dissemination systems like several Radio and Tv commercial broadcasters, dedicated radio receivers, EAS-SAME-SARMEX radio receivers and more tha 6700 public loud speakers. The other cities have only some of those systems. The Mw 8.2 Chiapas earthquake on September 7, despite the epicentral distance far of the first seismic detections (more than 180 km) and the low amplitudes of the P waves, the earthquake warning time gave more than 90 seconds to Mexico City before the arrivals of S waves with minor damages to the city in contrast with high damages in towns in the coast. This earthquake offered an opportunity to show the developments and lacks to reduce the risk, such as the need to increase the seismic detection coverage and the earthquake warning dissemination in towns with high seismic vulnerability. The Mw 7.1 Morelos earthquake on September 19 caused thousands of damages and hundreds of deaths and injuries in Mexico City, this earthquake is the second with the most damages after the Mw 8.1 Michoacán earthquake of September 19 on 1985. The earthquake early warning gave 11 seconds after the arrivals of S waves, however the activation occurred few seconds after the P waves arrives to Mexico City, and due to the seismic focus was near to the city, the P waves were felt for the people. The Accelerographic Network of Mexico City, reported absolute accelerations of 225 cm/s2 in the transition soils , which have never recorded in the Mexico Valley.

Earthquake Building Damage Mapping Based on Feature Analyzing Method from Synthetic Aperture Radar Data

NASA Astrophysics Data System (ADS)

An, L.; Zhang, J.; Gong, L.

2018-04-01

Playing an important role in gathering information of social infrastructure damage, Synthetic Aperture Radar (SAR) remote sensing is a useful tool for monitoring earthquake disasters. With the wide application of this technique, a standard method, comparing post-seismic to pre-seismic data, become common. However, multi-temporal SAR processes, are not always achievable. To develop a post-seismic data only method for building damage detection, is of great importance. In this paper, the authors are now initiating experimental investigation to establish an object-based feature analysing classification method for building damage recognition.

Concerns of Disaster Medical Assistance Team (DMAT) members about troubles at the nuclear power plant: experience from the Niigata Chuetsu-Oki earthquake, 16 July 2007, in Japan.

PubMed

Akashi, Makoto; Kumagaya, Ken; Kondo, Hisayoshi; Hirose, Yasuo

2010-06-01

An earthquake measuring 6.8 on the Richter scale struck the Niigata-Chuetsu region of Japan at 10:13 on 16 July 2007. The earthquake was followed by the sustained occurrence of numerous aftershocks, delaying the reconstruction of community lifelines. The earthquake affected the Kashiwazaki-Kariwa nuclear power plants (NPPs), the biggest NPP site in the world. The earthquake caused damage to NPPs, resulting in a small amount of radioactive materials being released into the air and the sea. However, no significant effects were detected in the public and the environment. As medical response to this earthquake, 42 Disaster Medical Assistance Teams (DMATs) were sent to hospitals and first-aid care centers at the NPP site. In order to evaluate the perceptions of the deployed DMAT personnel regarding concerns about the health effects of radiation and information about the damage to NPPs, questionnaires were sent to 40 facilities that dispatched DMATs to the earthquake area. Most of them were concerned with the effects of radiation, and adequate information about the problems at the NPPs was not communicated to them. This preliminary study suggests that communication of information is extremely important for DMAT members in the case of disasters, in particular if there exists a possibility of radiation exposure, since radiation cannot be detected by our senses. DMAT members are critical to any mass casualty incident, whether caused by humans or nature. We have learned from this earthquake that there is urgent need for an all-hazards approach, including a "combined disaster" strategy, which should be emphasized for current disaster planning and response. This is the first report on DMATs deployed to an earthquake site with damage to NPPs.

Earthquake and Tsunami Disaster Mitigation in The Marmara Region and Disaster Education in Turkey Part2 Yoshiyuki KANEDA Nagoya University Japan Agency for Marine-Earth Science and Technology (JAMSTEC) Haluk OZENER Boğaziçi University, Earthquake Researches Institute (KOERI) and Members of SATREPS Japan-Turkey project

NASA Astrophysics Data System (ADS)

Kaneda, Y.; Ozener, H.

2015-12-01

The 1999 Izumit Earthquake as the destructive earthquake occurred near the Marmara Sea. The Marmara Sea should be focused on because of a seismic gap in the North Anatolian fault. Istanbul is located around the Marmara Sea, so, if next earthquake will occur near Istanbul, fatal damages will be generated. The Japan and Turkey can share our own experiences during past damaging earthquakes and we can prepare for future large earthquakes in cooperation with each other. In earthquakes in Tokyo area and Istanbul area as the destructive earthquakes near high population cities, there are common disaster researches and measures. For disaster mitigation, we are progressing multidisciplinary researches. Our goals of this SATREPS project are as follows, To develop disaster mitigation policy and strategies based on multidisciplinary research activities. To provide decision makers with newly found knowledge for its implementation to the current regulations. To organize disaster education programs in order to increase disaster awareness in Turkey. To contribute the evaluation of active fault studies in Japan. This project is composed of four research groups. The first group is Marmara Earthquake Source region observationally research group. This group has 4 sub-themes such as Seismicity, Geodesy, Electromagnetics and Trench analyses. The second group focuses on scenario researches of earthquake occurrence along the North Anatolia fault and precise tsunami simulation in the Marmara region. Aims of the third group are improvements and constructions of seismic characterizations and damage predictions based on observation researches and precise simulations. The fourth group is promoting disaster educations using research result visuals. In this SATREPS project, we will integrate these research results for disaster mitigation in Marmara region and .disaster education in Turkey. We will have a presentation of the updated results of this SATREPS project.

Magnitude 8.1 Earthquake off the Solomon Islands

NASA Technical Reports Server (NTRS)

2007-01-01

On April 1, 2007, a magnitude 8.1 earthquake rattled the Solomon Islands, 2,145 kilometers (1,330 miles) northeast of Brisbane, Australia. Centered less than ten kilometers beneath the Earth's surface, the earthquake displaced enough water in the ocean above to trigger a small tsunami. Though officials were still assessing damage to remote island communities on April 3, Reuters reported that the earthquake and the tsunami killed an estimated 22 people and left as many as 5,409 homeless. The most serious damage occurred on the island of Gizo, northwest of the earthquake epicenter, where the tsunami damaged the hospital, schools, and hundreds of houses, said Reuters. This image, captured by the Landsat-7 satellite, shows the location of the earthquake epicenter in relation to the nearest islands in the Solomon Island group. Gizo is beyond the left edge of the image, but its triangular fringing coral reefs are shown in the upper left corner. Though dense rain forest hides volcanic features from view, the very shape of the islands testifies to the geologic activity of the region. The circular Kolombangara Island is the tip of a dormant volcano, and other circular volcanic peaks are visible in the image. The image also shows that the Solomon Islands run on a northwest-southeast axis parallel to the edge of the Pacific plate, the section of the Earth's crust that carries the Pacific Ocean and its islands. The earthquake occurred along the plate boundary, where the Australia/Woodlark/Solomon Sea plates slide beneath the denser Pacific plate. Friction between the sinking (subducting) plates and the overriding Pacific plate led to the large earthquake on April 1, said the United States Geological Survey (USGS) summary of the earthquake. Large earthquakes are common in the region, though the section of the plate that produced the April 1 earthquake had not caused any quakes of magnitude 7 or larger since the early 20th century, said the USGS.

Earthquakes; March-April 1975

USGS Publications Warehouse

Person, W.J.

1975-01-01

There were no major earthquakes (magnitude 7.0-7.9) in March or April; however, there were earthquake fatalities in Chile, Iran, and Venezuela and approximately 35 earthquake-related injuries were reported around the world. In the United States a magnitude 6.0 earthquake struck the Idaho-Utah border region. Damage was estimated at about a million dollars. The shock was felt over a wide area and was the largest to hit the continental Untied States since the San Fernando earthquake of February 1971. 

A Rapid Public Health Needs Assessment Framework for after Major Earthquakes Using High-Resolution Satellite Imagery.

PubMed

Zhao, Jian; Ding, Fan; Wang, Zhe; Ren, Jinghuan; Zhao, Jing; Wang, Yeping; Tang, Xuefeng; Wang, Yong; Yao, Jianyi; Li, Qun

2018-05-30

Background : Earthquakes causing significant damage have occurred frequently in China, producing enormous health losses, damage to the environment and public health issues. Timely public health response is crucial to reduce mortality and morbidity and promote overall effectiveness of rescue efforts after a major earthquake. Methods : A rapid assessment framework was established based on GIS technology and high-resolution remote sensing images. A two-step casualties and injures estimation method was developed to evaluate health loss with great rapidity. Historical data and health resources information was reviewed to evaluate the damage condition of medical resources and public health issues. Results : The casualties and injures are estimated within a few hours after an earthquake. For the Wenchuan earthquake, which killed about 96,000 people and injured about 288,000, the estimation accuracy is about 77%. 242/294 (82.3%) of the medical existing institutions were severely damaged. About 40,000 tons of safe drinking water was needed every day to ensure basic living needs. The risk of water-borne and foodborne disease, respiratory and close contact transmission disease is high. For natural foci diseases, the high-risk area of schistosomiasis was mapped in Lushan County as an example. Finally, temporary settlements for victims of earthquake were mapped. Conclusions : High resolution Earth observation technology can provide a scientific basis for public health emergency management in the major disasters field, which will be of great significance in helping policy makers effectively improve health service ability and public health emergency management in prevention and control of infectious diseases and risk assessment.

Security Implications of Induced Earthquakes

NASA Astrophysics Data System (ADS)

Jha, B.; Rao, A.

2016-12-01

The increase in earthquakes induced or triggered by human activities motivates us to research how a malicious entity could weaponize earthquakes to cause damage. Specifically, we explore the feasibility of controlling the location, timing and magnitude of an earthquake by activating a fault via injection and production of fluids into the subsurface. Here, we investigate the relationship between the magnitude and trigger time of an induced earthquake to the well-to-fault distance. The relationship between magnitude and distance is important to determine the farthest striking distance from which one could intentionally activate a fault to cause certain level of damage. We use our novel computational framework to model the coupled multi-physics processes of fluid flow and fault poromechanics. We use synthetic models representative of the New Madrid Seismic Zone and the San Andreas Fault Zone to assess the risk in the continental US. We fix injection and production flow rates of the wells and vary their locations. We simulate injection-induced Coulomb destabilization of faults and evolution of fault slip under quasi-static deformation. We find that the effect of distance on the magnitude and trigger time is monotonic, nonlinear, and time-dependent. Evolution of the maximum Coulomb stress on the fault provides insights into the effect of the distance on rupture nucleation and propagation. The damage potential of induced earthquakes can be maintained even at longer distances because of the balance between pressure diffusion and poroelastic stress transfer mechanisms. We conclude that computational modeling of induced earthquakes allows us to measure feasibility of weaponzing earthquakes and developing effective defense mechanisms against such attacks.

Historical earthquake research in Austria

NASA Astrophysics Data System (ADS)

Hammerl, Christa

2017-12-01

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

Seismic safety assessment of unreinforced masonry low-rise buildings in Pakistan and its neighbourhood

NASA Astrophysics Data System (ADS)

Korkmaz, K. A.

2009-06-01

Pakistan and neighbourhood experience numerous earthquakes, most of which result in damaged or collapsed buildings and loss of life that also affect the economy adversely. On 29 October, 2008, an earthquake of magnitude 6.5 occurred in Ziarat, Quetta Region, Pakistan which was followed by more than 400 aftershocks. Many villages were completely destroyed and more than 200 people died. The previous major earthquake was in 2005, known as the South Asian earthquake (Mw=7.6) occurred in Kashmir, where 80 000 people died. Inadequate building stock is to be blamed for the degree of disaster, as the majority of the buildings in the region are unreinforced masonry low-rise buildings. In this study, seismic vulnerability of regionally common unreinforced masonry low-rise buildings was investigated using probabilistic based seismic safety assessment. The results of the study showed that unreinforced masonry low-rise buildings display higher displacements and shear force. Probability of damage due to higher displacements and shear forces can be directly related to damage or collapse.

Efficient Risk Determination of Risk of Road Blocking by Means of MMS and Data of Buildings and Their Surrounding

NASA Astrophysics Data System (ADS)

Nose, Kazuhito; Hatake, Shuhei

2016-06-01

Massive earthquake named "Tonankai Massive earthquake" is predicted to occur in the near future and is feared to cause severe damage in Kinki District . "Hanshin-Awaji Massive Earthquake" in 1995 destroyed most of the buildings constructed before 1981 and not complying with the latest earthquake resistance standards. Collapsed buildings blocked roads, obstructed evacuation, rescue and firefighting operations and inflicted further damages.To alleviate the damages, it is important to predict the points where collapsed buildings are likely block the roads and to take precautions in advance. But big cities have an expanse of urban areas with densely-distributed buildings, and it requires time and cost to check each and every building whether or not it will block the road. In order to reduce blocked roads when a disaster strikes, we made a study and confirmed that the risk of road blocking can be determined easily by means of the latest technologies of survey and geographical information.

The MW 7.0 Haiti Earthquake of January 12, 2010: USGS/EERI Advance Reconnaissance Team Report

USGS Publications Warehouse

Eberhard, Marc O.; Baldridge, Steven; Marshall, Justin; Mooney, Walter; Rix, Glenn J.

2010-01-01

Executive Summary A field reconnaissance in Haiti by a five-member team with expertise in seismology and earthquake engineering has revealed a number of factors that led to catastrophic losses of life and property during the January 12, 2010, Mw 7.0 earthquake. The field study was conducted from January 26 to February 3, 2010, and included investigations in Port-au-Prince and the heavily damaged communities to the west, including Leogane, Grand Goave, Petite Goave, and Oliver. Seismology Despite recent seismic quiescence, Haiti has suffered similar devastating earthquakes in the historical past (1701, 1751, 1770 and 1860). Despite this knowledge of historical seismicity, Haiti had no seismograph stations during the main earthquake, so it is impossible to estimate accurately the intensity of ground motions. Nonetheless, the wide range of buildings damaged by the January 12, 2010, earthquake suggests that the ground motions contained seismic energy over a wide range of frequencies. Another earthquake of similar magnitude could strike at any time on the eastern end of the Enriquillo Fault, directly to the south of Port-au-Prince. Reconstruction must take this hazard into account. The four portable seismographs installed by the team recorded a series of small aftershocks. As expected, the ground motions recorded at a hard-rock site contained a greater proportion of high frequencies than the motions recorded at a soil site. Two of the stations continue to monitor seismic activity. A thorough field investigation of the mapped Enriquillo Fault south of the city of Leogane failed to find any evidence of surface faulting. This led the team to conclude that the earthquake was unlikely to have produced any surface rupture in the study area. Geotechnical Aspects Soil liquefaction, landslides and rockslides in cut slopes, and road embankment failures contributed to extensive damage in Port-au-Prince and elsewhere. A lack of detailed knowledge of the physical conditions of the soils (for example, lithology, stiffness, density, and thickness) made it difficult for us to quantitatively assess the role of ground-motion amplification in the widespread damage. Buildings The Haitian Ministry of Statistics and Informatics reported that one-story buildings represent 73 percent of the building inventory. Most ordinary, one-story houses have roofs made of sheet metal (82 percent), whereas most multistory houses and apartments have roofs made of concrete (71 percent). Walls made of concrete/block/stone predominate both in ordinary houses and apartments. It appears that the widespread damage to residences and commercial and government buildings was attributable to a great extent to the lack of earthquake-resistant design. In many cases, the structural types, member dimensions, and detailing practices were inadequate to resist strong ground motions. These vulnerabilities may have been exacerbated by poor construction practices. Reinforced concrete frames with concrete block masonry infill appeared to perform particularly poorly. Structures with light (timber or sheet metal) roofs performed better compared to structures with concrete roofs and slabs. The seismic performance of some buildings was adequate, and some of the damaged buildings appeared to have had low deformation demands. These observations suggest that structures designed and constructed with adequate stiffness and reinforcing details would have resisted the earthquake without being damaged severely. A damage survey of 107 buildings in downtown Port-au-Prince indicated that 28 percent had collapsed and another 33 percent were damaged enough to require repairs. A similar survey of 52 buildings in Leogane found that 62 percent had collapsed and another 31 percent required repairs. Bridges There was no evidence of bridge collapses attributable to the earthquake. Most bridges in Port-au-Prince are simple box culverts consisting of box girders 2.0 to 2.

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

Rodriguez, Mario E.

An area in earthquake risk reduction that needs an urgent examination is the selection of earthquake records for nonlinear dynamic analysis of structures. An often-mentioned shortcoming from results of nonlinear dynamic analyses of structures is that these results are limited to the type of records that these analyses use as input data. This paper proposes a procedure for selecting earthquake records for nonlinear dynamic analysis of structures. This procedure uses a seismic damage index evaluated using the hysteretic energy dissipated by a Single Degree of Freedom System (SDOF) representing a multi-degree-of freedom structure responding to an earthquake record, and themore » plastic work capacity of the system at collapse. The type of structural system is considered using simple parameters. The proposed method is based on the evaluation of the damage index for a suite of earthquake records and a selected type of structural system. A set of 10 strong ground motion records is analyzed to show an application of the proposed procedure for selecting earthquake records for structural design.« less

8 March 2010 Elazığ-Kovancilar (Turkey) Earthquake: observations on ground motions and building damage

USGS Publications Warehouse

Akkar, Sinan; Aldemir, A.; Askan, A.; Bakir, S.; Canbay, E.; Demirel, I.O.; Erberik, M.A.; Gulerce, Z.; Gulkan, Polat; Kalkan, Erol; Prakash, S.; Sandikkaya, M.A.; Sevilgen, V.; Ugurhan, B.; Yenier, E.

2011-01-01

An earthquake of MW = 6.1 occurred in the Elazığ region of eastern Turkey on 8 March 2010 at 02:32:34 UTC. The United States Geological Survey (USGS) reported the epicenter of the earthquake as 38.873°N-39.981°E with a focal depth of 12 km. Forty-two people lost their lives and 137 were injured during the event. The earthquake was reported to be on the left-lateral strike-slip east Anatolian fault (EAF), which is one of the two major active fault systems in Turkey. Teams from the Earthquake Engineering Research Center of the Middle East Technical University (EERC-METU) visited the earthquake area in the aftermath of the mainshock. Their reconnaissance observations were combined with interpretations of recorded ground motions for completeness. This article summarizes observations on building and ground damage in the area and provides a discussion of the recorded motions. No significant observations in terms of geotechnical engineering were made.

What are the determinants of post-traumatic stress disorder: age, gender, ethnicity or other? Evidence from 2008 Wenchuan earthquake.

PubMed

Kun, P; Tong, X; Liu, Y; Pei, X; Luo, H

2013-07-01

To estimate the prevalence of post-traumatic stress disorder (PTSD) and assess determinants related to PTSD symptoms among adult earthquake survivors after the 2008 Wenchuan earthquake in China. Cross-sectional multicluster sample surveys with data collected from four counties. Surveys were conducted separately in four counties in Sichuan Province, with a total of 2004 respondents. Beichuan County and Dujiangyan City were damaged more severely than Yaan County and Langzhong County during the earthquake. In total, 1890 households were represented, with a mean of 2.2 respondents per household. Data were collected using structured interviews, and the Harvard Trauma Questionnaire and Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition criteria were used to diagnose PTSD. The prevalence rates of suspected PTSD were 47.3% (n = 436) in heavily damaged areas and 10.4% (n = 93) in moderately damaged areas. The prevalence rates of PTSD symptoms among elderly, middle aged and young adults were 55.8%, 50.2% and 28.6% (P = 0.001), respectively, in heavily damaged areas. Older age, female gender, unmarried/divorced/widowed, ethnic minority, death of family member, no household income and damaged household were independent risk factors for PTSD symptoms in heavily damaged areas. Interventions designed to reduce PTSD among populations affected by the 2008 earthquake should focus on people without household incomes, those with damaged households and those who experienced the death of a family member. Effective, sustainable and culturally sensitive psychosocial interventions and mental health services are required, and attention should be directed to survivors who experienced the death of a family member, women and older adults following the devastating natural disaster. Governments should support income-generating activities and improve living conditions. Trained field personnel can assist with PTSD assessments and referrals, and existing rural healthcare services can be used to provide treatment for common psychiatric disorders. Copyright © 2013 The Royal Society for Public Health. Published by Elsevier Ltd. All rights reserved.

Map showing depth to bedrock of the Tacoma and part of the Centralia 30' x 60' quadrangles, Washington

USGS Publications Warehouse

Buchanan-Banks, Jane M.; Collins, Donley S.

1994-01-01

The heavily populated Puget Sound region in the State of Washington has experienced moderate to large earthquakes in the recent past (Nuttli, 1952; Mullineaux and others, 1967). Maps showing thickness of unconsolidated sedimentary deposits are useful aids in delineating areas where damage to engineered structures can result from increased shaking resulting from these earthquakes. Basins containing thick deposits of unconsolidated materials can amplify earthquakes waves and cause far more damage to structures than the same waves passing through bedrock (Singh and others, 1988; Algermissen and others, 1985). Configurations of deep sedimentary basins can also cause reflection and magnification of earthquake waves in ways still not fully understood and presently under investigation (Frankel and Vidale, 1992).

Performance evaluation of existing building structure with pushover analysis

NASA Astrophysics Data System (ADS)

Handana, MAP; Karolina, R.; Steven

2018-02-01

In the management of the infrastructure of the building, during the period of buildings common building damage as a result of several reasons, earthquakes are common. The building is planned to work for a certain service life. But during the certain service life, the building vulnerable to damage due to various things. Any damage to cultivate can be detected as early as possible, because the damage could spread, triggering and exacerbating the latest. The newest concept to earthquake engineering is Performance Based Earthquake Engineering (PBEE). PBEE divided into two, namely Performance Based Seismic Design (PBSD) and Performance Based Seismic Evaluation (PBSE). Evaluation on PBSE one of which is the analysis of nonlinear pushover. Pushover analysis is a static analysis of nonlinear where the influence of the earthquake plan on building structure is considered as burdens static catch at the center of mass of each floor, which it was increased gradually until the loading causing the melting (plastic hinge) first within the building structure, then the load increases further changes the shapes of post-elastic large it reached the condition of elastic. Then followed melting (plastic hinge) in the location of the other structured.

The Fusion of Financial Analysis and Seismology: Statistical Methods from Financial Market Analysis Applied to Earthquake Data

NASA Astrophysics Data System (ADS)

Ohyanagi, S.; Dileonardo, C.

2013-12-01

As a natural phenomenon earthquake occurrence is difficult to predict. Statistical analysis of earthquake data was performed using candlestick chart and Bollinger Band methods. These statistical methods, commonly used in the financial world to analyze market trends were tested against earthquake data. Earthquakes above Mw 4.0 located on shore of Sanriku (37.75°N ~ 41.00°N, 143.00°E ~ 144.50°E) from February 1973 to May 2013 were selected for analysis. Two specific patterns in earthquake occurrence were recognized through the analysis. One is a spread of candlestick prior to the occurrence of events greater than Mw 6.0. A second pattern shows convergence in the Bollinger Band, which implies a positive or negative change in the trend of earthquakes. Both patterns match general models for the buildup and release of strain through the earthquake cycle, and agree with both the characteristics of the candlestick chart and Bollinger Band analysis. These results show there is a high correlation between patterns in earthquake occurrence and trend analysis by these two statistical methods. The results of this study agree with the appropriateness of the application of these financial analysis methods to the analysis of earthquake occurrence.

Money matters: Rapid post-earthquake financial decision-making

USGS Publications Warehouse

Wald, David J.; Franco, Guillermo

2016-01-01

Post-earthquake financial decision-making is a realm beyond that of many people. In the immediate aftermath of a damaging earthquake, billions of dollars of relief, recovery, and insurance funds are in the balance through new financial instruments that allow those with resources to hedge against disasters and those at risk to limit their earthquake losses and receive funds for response and recovery.

BAREPP: Earthquake preparedness for the San Francisco Bay area

USGS Publications Warehouse

1986-01-01

The threat of major and damaging earthquakes in California is a fact. How people respond to that threat is a concern shared by many local, state, federal, volunteer and private sector organizations. The Bay Area Regional Earthquake Preparedness Project (BAREPP) promotes comprehensive earthquake preparedness actions by these organizations and provides technical and planning assistance for a variety of programs.

A newly discovered historical earthquake or merely a chronological mistake? Report of Mary Eliza Rogers from October 10, 1856

NASA Astrophysics Data System (ADS)

Zohar, Motti

2017-09-01

In her nineteenth century book "Domestic Life in Palestine", Mary Eliza Rogers describes the earthquake she had experienced in Haifa in the middle of the night between the 10th and 11th of October 1856. Although she reports that the earthquake was well felt in northern Palestine and even slightly damaged structures in Haifa, she is the only one who reported the event. However, on the following night, a destructive earthquake that occurred close to Crete was reported by many contemporary sources. Rogers' report is not cited in any of the existing earthquake catalogs or literature. Thus, the question arises is whether what she reports is an earthquake that was unknown to us till now or perhaps she merely dated incorrectly the event she had experienced. To resolve this question, I interpreted her description of the moon phase at the time of the earthquake occurrence and concluded that Rogers incorrectly dated the event whereas in fact what she had experienced was the Crete earthquake. The rest of her description is probably reliable and reinforces reports of damaged localities along the coast of northern Palestine and southern Lebanon.

Landslides and dam damage resulting from the Jiuzhaigou earthquake (8 August 2017), Sichuan, China

PubMed Central

Wang, Yun-sheng; Luo, Yong-hong; Li, Jia; Zhang, Xin; Shen, Tong

2018-01-01

At 21.19 on 8 August 2017, an Ms 7.0 earthquake struck the Jiuzhaigou scenic spot in northwestern Sichuan Province, China. The Jiuzhaigou earthquake is a strike-slip earthquake with a focal depth of 20 km at 33.20° N and 103.82° E, and was caused by two concealed faults. According to emergency investigations and remote sensing interpretations, the Jiuzhaigou earthquake triggered 1780 landslides, damaged one dam (Nuorilang Waterfall) and broke one dam (Huohua Lake). The landslides mainly occurred in the Rize Valley and Shuzheng Valley and in Jiuzhai Paradise. The landslides involved hanging wall and back-slope effects, and the slope angle, slope aspect, seismic faults and valley trend were obviously related to the occurrence of the landslides. Specifically, most of the landslides were shallow landslides, rockfalls and rock avalanches and were small in scale. The failure modes of landslides mainly include wedge rock mass failure, residual deposit failure, relaxed rock mass failure and weathered rock mass failure. The initial low stability of the dam coupled with the topographic effect, back-slope effect and excess pore water pressure led to damage to the Nuorilang Waterfall dam. PMID:29657755

Landslides and dam damage resulting from the Jiuzhaigou earthquake (8 August 2017), Sichuan, China

NASA Astrophysics Data System (ADS)

Zhao, Bo; Wang, Yun-sheng; Luo, Yong-hong; Li, Jia; Zhang, Xin; Shen, Tong

2018-03-01

At 21.19 on 8 August 2017, an Ms 7.0 earthquake struck the Jiuzhaigou scenic spot in northwestern Sichuan Province, China. The Jiuzhaigou earthquake is a strike-slip earthquake with a focal depth of 20 km at 33.20° N and 103.82° E, and was caused by two concealed faults. According to emergency investigations and remote sensing interpretations, the Jiuzhaigou earthquake triggered 1780 landslides, damaged one dam (Nuorilang Waterfall) and broke one dam (Huohua Lake). The landslides mainly occurred in the Rize Valley and Shuzheng Valley and in Jiuzhai Paradise. The landslides involved hanging wall and back-slope effects, and the slope angle, slope aspect, seismic faults and valley trend were obviously related to the occurrence of the landslides. Specifically, most of the landslides were shallow landslides, rockfalls and rock avalanches and were small in scale. The failure modes of landslides mainly include wedge rock mass failure, residual deposit failure, relaxed rock mass failure and weathered rock mass failure. The initial low stability of the dam coupled with the topographic effect, back-slope effect and excess pore water pressure led to damage to the Nuorilang Waterfall dam.

Landslides and dam damage resulting from the Jiuzhaigou earthquake (8 August 2017), Sichuan, China.

PubMed

Zhao, Bo; Wang, Yun-Sheng; Luo, Yong-Hong; Li, Jia; Zhang, Xin; Shen, Tong

2018-03-01

At 21.19 on 8 August 2017, an Ms 7.0 earthquake struck the Jiuzhaigou scenic spot in northwestern Sichuan Province, China. The Jiuzhaigou earthquake is a strike-slip earthquake with a focal depth of 20 km at 33.20° N and 103.82° E, and was caused by two concealed faults. According to emergency investigations and remote sensing interpretations, the Jiuzhaigou earthquake triggered 1780 landslides, damaged one dam (Nuorilang Waterfall) and broke one dam (Huohua Lake). The landslides mainly occurred in the Rize Valley and Shuzheng Valley and in Jiuzhai Paradise. The landslides involved hanging wall and back-slope effects, and the slope angle, slope aspect, seismic faults and valley trend were obviously related to the occurrence of the landslides. Specifically, most of the landslides were shallow landslides, rockfalls and rock avalanches and were small in scale. The failure modes of landslides mainly include wedge rock mass failure, residual deposit failure, relaxed rock mass failure and weathered rock mass failure. The initial low stability of the dam coupled with the topographic effect, back-slope effect and excess pore water pressure led to damage to the Nuorilang Waterfall dam.

Rapid repair of severely earthquake-damaged bridge piers with flexural-shear failure mode

NASA Astrophysics Data System (ADS)

Sun, Zhiguo; Wang, Dongsheng; Du, Xiuli; Si, Bingjun

2011-12-01

An experimental study was conducted to investigate the feasibility of a proposed rapid repair technique for severely earthquake-damaged bridge piers with flexural-shear failure mode. Six circular pier specimens were first tested to severe damage in flexural-shear mode and repaired using early-strength concrete with high-fluidity and carbon fiber reinforced polymers (CFRP). After about four days, the repaired specimens were tested to failure again. The seismic behavior of the repaired specimens was evaluated and compared to the original specimens. Test results indicate that the proposed repair technique is highly effective. Both shear strength and lateral displacement of the repaired piers increased when compared to the original specimens, and the failure mechanism of the piers shifted from flexural-shear failure to ductile flexural failure. Finally, a simple design model based on the Seible formulation for post-earthquake repair design was compared to the experimental results. It is concluded that the design equation for bridge pier strengthening before an earthquake could be applicable to seismic repairs after an earthquake if the shear strength contribution of the spiral bars in the repaired piers is disregarded and 1.5 times more FRP sheets is provided.

Thermal anomaly before earthquake and damage assessment using remote sensing data for 2014 Yutian earthquake

NASA Astrophysics Data System (ADS)

Zhang, Yanmei; Huang, Haiying; Jiang, Zaisen; Fang, Ying; Cheng, Xiao

2014-12-01

Thermal anomaly appears to be a significant precursor of some strong earthquakes. In this study, time series of MODIS Land Surface Temperature (LST) products from 2001 to 2014 are processed and analyzed to locate possible anomalies prior to the Yutian earthquake (12 February 2014, Xinjiang, CHINA). In order to reduce the seasonal or annual effects from the LST variations, also to avoid the rainy and cloudy weather in this area, a background mean of ten-day nighttime LST are derived using averaged MOD11A2 products from 2001 to 2012. Then the ten-day LST data from Jan 2014 to FebJanuary 2014 were differenced using the above background. Abnormal LST increase before the earthquake is quite obvious from the differential images, indicating that this method is useful in such area with high mountains and wide-area deserts. Also, in order to assess the damage to infrastructure, China's latest civilian high-resolution remote sensing satellite - GF-1 remote sensed data are applied to the affected counties in this area. The damaged infrastructures and ground surface could be easily interpreted in the fused pan-chromatic and multi-spectral images integrating both texture and spectral information.

Chapter C. The Loma Prieta, California, Earthquake of October 17, 1989 - Building Structures

USGS Publications Warehouse

Çelebi, Mehmet

1998-01-01

Several approaches are used to assess the performance of the built environment following an earthquake -- preliminary damage surveys conducted by professionals, detailed studies of individual structures, and statistical analyses of groups of structures. Reports of damage that are issued by many organizations immediately following an earthquake play a key role in directing subsequent detailed investigations. Detailed studies of individual structures and statistical analyses of groups of structures may be motivated by particularly good or bad performance during an earthquake. Beyond this, practicing engineers typically perform stress analyses to assess the performance of a particular structure to vibrational levels experienced during an earthquake. The levels may be determined from recorded or estimated ground motions; actual levels usually differ from design levels. If a structure has seismic instrumentation to record response data, the estimated and recorded response and behavior of the structure can be compared.

Concerns over modeling and warning capabilities in wake of Tohoku Earthquake and Tsunami

NASA Astrophysics Data System (ADS)

Showstack, Randy

2011-04-01

Improved earthquake models, better tsunami modeling and warning capabilities, and a review of nuclear power plant safety are all greatly needed following the 11 March Tohoku earthquake and tsunami, according to scientists at the European Geosciences Union's (EGU) General Assembly, held 3-8 April in Vienna, Austria. EGU quickly organized a morning session of oral presentations and an afternoon panel discussion less than 1 month after the earthquake and the tsunami and the resulting crisis at Japan's Fukushima nuclear power plant, which has now been identified as having reached the same level of severity as the 1986 Chernobyl disaster. Many of the scientists at the EGU sessions expressed concern about the inability to have anticipated the size of the earthquake and the resulting tsunami, which appears likely to have caused most of the fatalities and damage, including damage to the nuclear plant.

Accounts of damage from historical earthquakes in the northeastern Caribbean to aid in the determination of their location and intensity magnitudes

USGS Publications Warehouse

Flores, Claudia H.; ten Brink, Uri S.; Bakun, William H.

2012-01-01

Documentation of an event in the past depended on the population and political trends of the island, and the availability of historical documents is limited by the physical resource digitization schedule and by the copyright laws of each archive. Examples of documents accessed are governors' letters, newspapers, and other circulars published within the Caribbean, North America, and Western Europe. Key words were used to search for publications that contain eyewitness accounts of various large earthquakes. Finally, this catalog provides descriptions of damage to buildings used in previous studies for the estimation of moment intensity (MI) and location of significantly damaging or felt earthquakes in Hispaniola and in the northeastern Caribbean, all of which have been described in other studies.

Using structures of the August 24, 2016 Amatrice earthquake affected area as seismoscopes for assessing ground motion characteristics and parameters of the main shock and its largest aftershocks

NASA Astrophysics Data System (ADS)

Carydis, Panayotis; Lekkas, Efthymios; Mavroulis, Spyridon

2017-04-01

On August 24, 2016 an Mw 6.0 earthquake struck Central Apennines (Italy) resulting in 299 fatalities, 388 injuries and about 3000 homeless in Amatrice wider area. Normal faulting surface ruptures along the western slope of Mt Vettore along with provided focal mechanisms demonstrated a NW-SE striking and SE dipping causative normal fault. The dominant building types in the affected area are unreinforced masonry (URM) and reinforced concrete (RC) buildings. Based on our macroseismic survey in the affected area immediately after the earthquake, RC buildings suffered non-structural damage including horizontal cracking of infill and internal partition walls, detachment of infill walls from the surrounding RC frame and detachment of large plaster pieces from infill walls as well as structural damage comprising soft story failure, symmetrical buckling of rods, compression damage at midheight of columns and bursting of over-stressed columns resulting in partial or total collapse. Damage in RC buildings was due to poor quality of concrete, inadequacy of reinforcement, inappropriate foundation close to the edge of slopes leading to differential settlements, poor workmanship and the destructive effect of vertical ground motions. Damage in URM buildings ranged from cracks and detachment of large plaster pieces from load-bearing walls to destruction due to poor workmanship with randomly placed materials bound by low-strength mortars, the effect of the vertical ground motion, inadequate repair and/or strengthening after previous earthquakes as well as inadequate interventions, additions and extensions to older URM buildings. During field surveying, the authors had the opportunity to observe damage induced not only by the main shock but also by its largest aftershocks (Mw 4.5-5.3) during the first three days of the aftershock sequence (August 24-26). Bearing in mind that: (a) soil conditions in foundations of the affected villages were more or less similar, (b) building damage induced by the studied earthquakes indicated the predominant effect of the vertical ground motion on buildings based on already reported building damage induced by recent destructive events in the Mediterranean region, (c) the conventional dynamic parameters of buildings did not play a significant role in their seismic response against the vertical component, due to its impact type of loading, (d) structures and materials presented similar response to ground motions almost independent from type and existing quality, and carried memories from previous large shocks of this sequence, (e) the main shock and its largest aftershocks caused building damage including spatial homothetic motions that reached statistically significant levels, it is concluded that the main shock and its largest aftershocks had similar focal mechanism parameters (normal faulting), were shallow events and were near-field earthquakes with short duration but high amplitude and the vertical component of the earthquakes' ground motion has prevailed. The aforementioned approach based solely on macroseismic observations was applied in the case of the 1755 Great Lisbon earthquake in order to determine its mechanism and epicenter location. Thus, it is suggested that the aforementioned methodology can be applied either in past historic earthquakes or complementarily in cases when the available seismological data are insufficient.

33 CFR 222.4 - Reporting earthquake effects.

Code of Federal Regulations, 2012 CFR

2012-07-01

.... This indicates the possibility that earthquake induced loads may not have been adequately considered in... misalignment of hydraulic control structures or gates. Induced dynamic loading on earth dams may result in loss... area where the earthquake is felt but causes no or insignificant damage (Modified Mercalli Intensity VI...

33 CFR 222.4 - Reporting earthquake effects.

Code of Federal Regulations, 2013 CFR

2013-07-01

.... This indicates the possibility that earthquake induced loads may not have been adequately considered in... misalignment of hydraulic control structures or gates. Induced dynamic loading on earth dams may result in loss... area where the earthquake is felt but causes no or insignificant damage (Modified Mercalli Intensity VI...

Earthquakes and Schools

ERIC Educational Resources Information Center

National Clearinghouse for Educational Facilities, 2008

2008-01-01

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

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.

1964 Great Alaska Earthquake: a photographic tour of Anchorage, Alaska

USGS Publications Warehouse

Thoms, Evan E.; Haeussler, Peter J.; Anderson, Rebecca D.; McGimsey, Robert G.

2014-01-01

On March 27, 1964, at 5:36 p.m., a magnitude 9.2 earthquake, the largest recorded earthquake in U.S. history, struck southcentral Alaska (fig. 1). The Great Alaska Earthquake (also known as the Good Friday Earthquake) occurred at a pivotal time in the history of earth science, and helped lead to the acceptance of plate tectonic theory (Cox, 1973; Brocher and others, 2014). All large subduction zone earthquakes are understood through insights learned from the 1964 event, and observations and interpretations of the earthquake have influenced the design of infrastructure and seismic monitoring systems now in place. The earthquake caused extensive damage across the State, and triggered local tsunamis that devastated the Alaskan towns of Whittier, Valdez, and Seward. In Anchorage, the main cause of damage was ground shaking, which lasted approximately 4.5 minutes. Many buildings could not withstand this motion and were damaged or collapsed even though their foundations remained intact. More significantly, ground shaking triggered a number of landslides along coastal and drainage valley bluffs underlain by the Bootlegger Cove Formation, a composite of facies containing variably mixed gravel, sand, silt, and clay which were deposited over much of upper Cook Inlet during the Late Pleistocene (Ulery and others, 1983). Cyclic (or strain) softening of the more sensitive clay facies caused overlying blocks of soil to slide sideways along surfaces dipping by only a few degrees. This guide is the document version of an interactive web map that was created as part of the commemoration events for the 50th anniversary of the 1964 Great Alaska Earthquake. It is accessible at the U.S. Geological Survey (USGS) Alaska Science Center website: http://alaska.usgs.gov/announcements/news/1964Earthquake/. The website features a map display with suggested tour stops in Anchorage, historical photographs taken shortly after the earthquake, repeat photography of selected sites, scanned documents, and small-scale maps, as well as links to slideshows of additional photographs and Google Street View™ scenes. Buildings in Anchorage that were severely damaged, sites of major landslides, and locations of post-earthquake engineering responses are highlighted. The web map can be used online as a virtual tour or in a physical self-guided tour using a web-enabled Global Positioning System (GPS) device. This publication serves the purpose of committing most of the content of the web map to a single distributable document. As such, some of the content differs from the online version.

Effect of the 2015 earthquake on pediatric inpatient pattern at a tertiary care hospital in Nepal.

PubMed

Giri, Bishnu Rath; Chapagain, Ram Hari; Sharma, Samana; Shrestha, Sandeep; Ghimire, Sunita; Shankar, P Ravi

2018-02-05

Earthquakes impact child health in many ways. Diseases occurring immediately following an earthquake have been studied in field based hospitals but studies on the inpatient disease pattern among children without trauma in a permanent hospital setup is lacking. We examined the diagnoses of all children without trauma, admitted to Kanti Children's Hospital, Kathmandu for fifteen-week duration (from 4th week to end of the 18th week) following the 7.8 magnitude Nepal earthquake on 25th April 2015. The admitted children were grouped based on direct effect of earthquake on their family (house damaged or family member injured or dead) and on whether their place of residence was located in an earthquake affected district. Most common diagnoses were identified and their distribution between the aforementioned groups analyzed to examine differences, if any, in disease occurrence or presentation. The fifteen weeks study duration was divided into three parts of five weeks each, to study trends in illness presentation. Variables were compared among various groups using appropriate statistical tests (p < 0.05). A total of 1057 patients were admitted. The proportion of patients requiring admission for pneumonia, acute gastroenteritis and acute or poststreptococcal glomerulonephritis (AGN/PSGN) was significantly higher among children belonging to earthquake affected districts. Proportion of patients with any infective condition was also significantly higher in this group. Acute gastroenteritis and any infective condition were significantly higher among children from substantially affected families. The proportion of AGN/PSGN among admitted patients increased in successive time categories among patients from affected districts and from substantially affected families. Urinary Tract Infection, bronchiolitis, tuberculosis, pleural effusion, protein energy malnutrition/failure to thrive, nephrotic syndrome, meningitis/meningoencephalitis, epilepsy or seizure disorders, leukemia/malignancies, enteric fever, infective hepatitis and congenital heart disease were not significantly different among children from affected and not affected districts or between substantially affected and not affected families. Patients from substantially affected families were admitted to semi-intensive care ward or ICU in significantly higher proportions (12.6% vs 7.8%, p = 0.014). Children seeking care for certain diseases were more likely to be from earthquake affected families and districts. Those from affected families required critical care more often.

Fluid-rock interaction during a large earthquake recorded in fault gouge: A case study of the Nojima fault, Japan

NASA Astrophysics Data System (ADS)

Bian, D.; Lin, A.

2016-12-01

Distinguishing the seismic ruptures during the earthquake from a lot of fractures in borehole core is very important to understand rupture processes and seismic efficiency. In particular, a great earthquake like the 1995 Mw 7.2 Kobe earthquake, but again, evidence has been limited to the grain size analysis and the color of fault gouge. In the past two decades, increasing geological evidence has emerged that seismic faults and shear zones within the middle to upper crust play a crucial role in controlling the architectures of crustal fluid migration. Rock-fluid interactions along seismogenic faults give us a chance to find the seismic ruptures from the same event. Recently, a new project of "Drilling into Fault Damage Zone" has being conducted by Kyoto University on the Nojima Fault again after 20 years of the 1995 Kobe earthquake for an integrated multidisciplinary study on the assessment of activity of active faults involving active tectonics, geochemistry and geochronology of active fault zones. In this work, we report on the signature of slip plane inside the Nojima Fault associated with individual earthquakes on the basis of trace element and isotope analyses. Trace element concentrations and 87Sr/86Sr ratios of fault gouge and host rocks were determined by an inductively coupled plasma mass spectrometer (ICP-MS) and thermal ionization mass spectrometry (TIMS). Samples were collected from two trenches and an outcrop of Nojima Fault which. Based on the geochemical result, we interpret these geochemical results in terms of fluid-rock interactions recorded in fault friction during earthquake. The trace-element enrichment pattern of the slip plane can be explained by fluid-rock interactions at high temperature. It also can help us find the main coseismic fault slipping plane inside the thick fault gouge zone.

GIS characterization of spatially distributed lifeline damage

USGS Publications Warehouse

Toprak, Selcuk; O'Rourke, Thomas; Tutuncu, Ilker

1999-01-01

This paper describes the visualization of spatially distributed water pipeline damage following an earthquake using geographical information systems (GIS). Pipeline damage is expressed as a repair rate (RR). Repair rate contours are developed with GIS by dividing the study area into grid cells (n ?? n), determining the number of particular pipeline repairs in each grid cell, and dividing the number of repairs by the length of that pipeline in each cell area. The resulting contour plot is a two-dimensional visualization of point source damage. High damage zones are defined herein as areas with an RR value greater than the mean RR for the entire study area of interest. A hyperbolic relationship between visual display of high pipeline damage zones and grid size, n, was developed. The relationship is expressed in terms of two dimensionless parameters, threshold area coverage (TAC) and dimensionless grid size (DGS). The relationship is valid over a wide range of different map scales spanning approximately 1,200 km2 for the largest portion of the Los Angeles water distribution system to 1 km2 for the Marina in San Francisco. This relationship can aid GIS users to get sufficiently refined, but easily visualized, maps of damage patterns.

Seismic damage identification using multi-line distributed fiber optic sensor system

NASA Astrophysics Data System (ADS)

Ou, Jinping; Hou, Shuang

2005-06-01

Determination of the actual nonlinear inelastic response mechanisms developed by civil structures such as buildings and bridges during strong earthquakes and post-earthquake damage assessment of these structures represent very difficult challenges for earthquake structural engineers. One of the main reasons is that the traditional sensor can't serve for such a long period to cover an earthquake and the seismic damage location in the structure can't be predicted in advance definitely. It is thought that the seismic damage of reinforced concrete (RC) structure can be related to the maximum response the structure, which can also be related to the cracks on the concrete. A distributed fiber optic sensor was developed to detect the cracks on the reinforced concrete structure under load. Fiber optic couples were used in the sensor system to extend the sensor system's capacity from one random point detection to more. An optical time domain reflectometer (OTDR) is employed for interrogation of the sensor signal. Fiber optic sensors are attached on the surface of the concrete by the epoxy glue. By choosing the strength of epoxy, the damage state of the concrete can be responded to the occurrence of the Fresnel scattering in the fiber optic sensor. Experiments involved monotonic loading to failure. Finally, the experimental results in terms of crack detection capability are presented and discussed.

Mitigation of Debris Flow Damage--­ A Case Study of Debris Flow Damage

NASA Astrophysics Data System (ADS)

Lin, J. C.; Jen, C. H.

Typhoon Toraji caused more than 30 casualties in Central Taiwan on the 31st July 2001. It was the biggest Typhoon since the Chi-Chi earthquake of 1999 with huge amounts of rainfall. Because of the influence of the earthquake, loose debris falls and flows became major hazards in Central Taiwan. Analysis of rainfall data and sites of slope failure show that damage from these natural hazards were enhanced as a result of the Chi-Chi earthquake. Three main types of hazard occurred in Central Taiwan: land- slides, debris flows and gully erosion. Landslides occurred mainly along hill slopes and banks of channels. Many dams and houses were destroyed by flooding. Debris flows occurred during typhoon periods and re-activated ancient debris depositions. Many new gullies were therefore developed from deposits loosened and shaken by the earthquake. This paper demonstrates the geological/geomorphological background of the hazard area, and reviews methods of damage mitigation in central Taiwan. A good example is Hsi-Tou, which had experienced no gully erosion for more than 40 years. The area experienced much gully erosion as a result of the combined effects of earth- quake and typhoon. Although Typhoon Toraji produced only 30% of the rainfall of Typhoon Herb of 1996, it caused more damage in the Hsi-Tou area. The mitigation of debris flow hazards in Hsi-tou area is discussed in this paper.

Modelling earthquake ruptures with dynamic off-fault damage

NASA Astrophysics Data System (ADS)

Okubo, Kurama; Bhat, Harsha S.; Klinger, Yann; Rougier, Esteban

2017-04-01

Earthquake rupture modelling has been developed for producing scenario earthquakes. This includes understanding the source mechanisms and estimating far-field ground motion with given a priori constraints like fault geometry, constitutive law of the medium and friction law operating on the fault. It is necessary to consider all of the above complexities of a fault systems to conduct realistic earthquake rupture modelling. In addition to the complexity of the fault geometry in nature, coseismic off-fault damage, which is observed by a variety of geological and seismological methods, plays a considerable role on the resultant ground motion and its spectrum compared to a model with simple planer fault surrounded by purely elastic media. Ideally all of these complexities should be considered in earthquake modelling. State of the art techniques developed so far, however, cannot treat all of them simultaneously due to a variety of computational restrictions. Therefore, we adopt the combined finite-discrete element method (FDEM), which can effectively deal with pre-existing complex fault geometry such as fault branches and kinks and can describe coseismic off-fault damage generated during the dynamic rupture. The advantage of FDEM is that it can handle a wide range of length scales, from metric to kilometric scale, corresponding to the off-fault damage and complex fault geometry respectively. We used the FDEM-based software tool called HOSSedu (Hybrid Optimization Software Suite - Educational Version) for the earthquake rupture modelling, which was developed by Los Alamos National Laboratory. We firstly conducted the cross-validation of this new methodology against other conventional numerical schemes such as the finite difference method (FDM), the spectral element method (SEM) and the boundary integral equation method (BIEM), to evaluate the accuracy with various element sizes and artificial viscous damping values. We demonstrate the capability of the FDEM tool for modelling earthquake ruptures. We then modelled earthquake ruptures allowing for coseismic off-fault damage with appropriate fracture nucleation and growth criteria. We studied the effect of different conditions such as rupture speed (sub-Rayleigh or supershear), the orientation of the initial maximum principal stress with respect to the fault and the magnitude of the initial stress (to mimic depth). The comparison between the sub-Rayleigh and supershear case shows that the coseismic off-fault damage is enhanced in the supershear case when compared with the sub-Rayleigh case. The orientation of the maximum principal stress also has significant difference such that the dynamic off-fault cracking is more likely to occur on the extensional side of the fault for high principal stress orientation. It is found that the coseismic off-fault damage reduces the rupture speed due to the dissipation of the energy by dynamic off-fault cracking generated in the vicinity of the rupture front. In terms of the ground motion amplitude spectra it is shown that the high-frequency radiation is enhanced by the coseismic off-fault damage though it is quickly attenuated. This is caused by the intricate superposition of the radiation generated by the off-fault damage and the perturbation of the rupture speed on the main fault.

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.

Damage Assessment Map from Interferometric Coherence

NASA Astrophysics Data System (ADS)

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

2010-12-01

Large earthquakes cause buildings to collapse, which often claims the lives of many. For example, 2010 Haiti earthquake killed about 230,000 people, with about 280,000 buildings collapsed or severely damaged. When a major earthquake hits an urban area, one of the most critical information for rescue operations is rapid and accurate assessment of building-collapse areas. From a study on 2003 Bam earthquake in Iran, interferometric coherence was proved useful for earthquake damage assessment (Fielding et al., 2005) when similar perpendicular baselines can be found for pre- and coseismic interferometric pairs and when there is little temporal and volume decorrelation. In this study we develop a new algorithm to create a more robust and accurate damage assessment map using interferometric coherence despite different interferometric baselines and with other decorrelation sources. We test the algorithm on a building block that recently underwent demolition, which is a proxy for building collapse due to earthquakes, for new construction in the City of Pasadena, California. The size of the building block is about 150 m E-W and 300 m N-S, and the demolition project started on April 23, 2007 and continued until January 22, 2008. After we process Japanese L-band ALOS PALSAR data with ROI_PAC, an interferometric coherence map that spans the demolition period is registered to a coherence map before the demolition, and the relative bias of the coherence values are removed, then a causality constraint is applied to enhance the change due to demolition. The results show clear change in coherence at the demolition site. We improve the signal-to-noise ratio of the coherence change at the demolition site from 17.3 (for simple difference) to 44.6 (with the new algorithm). The damage assessment map algorithm will become more useful with the emergence of InSAR missions with more frequent data acquisition, such as Sentinel-1 and DESDynI.

Earth Observations taken by the Expedition 22 Crew

NASA Image and Video Library

2010-02-27

ISS022-E-074881 (27 Feb. 2010) --- Earthquake damage in Concepcion, Chile is featured in this image photographed by an Expedition 22 crew member on the International Space Station. This detailed view of the Chilean cities of Concepcion and Hualpen was acquired from the space station approximately seven hours after a magnitude 8.8 earthquake occurred offshore 115 kilometers to the north-northeast. Much of the Chilean coastline is located above the boundary between the converging Nazca and South American tectonic plates. This type of plate boundary is known as a subduction zone; such zones frequently experience moderate to strong earthquakes as one tectonic plate overrides the other. The largest earthquake worldwide during the past 200 years (magnitude 9.5 in May 1960) had a source region approximately 230 kilometers north of the Feb. 27 quake. While the image is not detailed enough to see damage to individual buildings or roadways some indicators of earthquake damage are visible. A dark smoke plume is visible at lower left near an oil refinery in Hualpen. At lower right, parts of the road bed of a single-lane bridge over the Bio-Bio River appear to have collapsed. A smaller, white smoke plume is visible at right near the Universidad de Concepcion. Smoke and haze possibly related to the earthquake was noted over Santiago, Chile in data acquired by the MODIS sensor less than one hour after this photograph was taken.

Natural Hazard Public Policy Implications of the May 12, 2008 M7.9 Wenchuan Earthquake, Sichuan, China

NASA Astrophysics Data System (ADS)

Cydzik, K.; Hamilton, D.; Stenner, H. D.; Cattarossi, A.; Shrestha, P. L.

2009-12-01

The May 12, 2008 M7.9 Wenchuan Earthquake in Sichuan Province, China killed almost 90,000 people and affected a population of over 45.5 million throughout western China. Shaking caused the destruction of five million buildings, many of them homes and schools, and damaged 21 million other structures, inflicting devastating impacts to communities. Landslides, a secondary effect of the shaking, caused much of the devastation. Debris flows buried schools and homes, rock falls crushed cars, and rockslides, landslides, and rock avalanches blocked streams and rivers creating massive, unstable landslide dams, which formed “quake lakes” upstream of the blockages. Impassable roads made emergency access slow and extremely difficult. Collapses of buildings and structures large and small took the lives of many. Damage to infrastructure impaired communication, cut off water supplies and electricity, and put authorities on high alert as the integrity of large engineered dams were reviewed. During our field reconnaissance three months after the disaster, evidence of the extent of the tragedy was undeniably apparent. Observing the damage throughout Sichuan reminded us that earthquakes in the United States and throughout the world routinely cause widespread damage and destruction to lives, property, and infrastructure. The focus of this poster is to present observations and findings based on our field reconnaissance regarding the scale of earthquake destruction with respect to slope failures, landslide dams, damage to infrastructure (e.g., schools, engineered dams, buildings, roads, rail lines, and water resources facilities), human habitation within the region, and the mitigation and response effort to this catastrophe. This is presented in the context of the policy measures that could be developed to reduce risks of similar catastrophes. The rapid response of the Chinese government and the mobilization of the Chinese People’s Liberation Army to help the communities affected by the earthquake have allowed survivors to begin rebuilding their lives. However, the long-term impact of the earthquake continues to make headlines. Post-earthquake landslides and debris flows initiated by storm events have continued to impart devastation on the region. Events such as the Wenchuan Earthquake provide unique opportunities for engineers, scientists, and policy makers to collaborate for purposes of exploring the details of natural hazards and developing sound policies to protect lives and property in the future.

Disaster mitigation science for Earthquakes and Tsunamis -For resilience society against natural disasters-

NASA Astrophysics Data System (ADS)

Kaneda, Y.; Takahashi, N.; Hori, T.; Kawaguchi, K.; Isouchi, C.; Fujisawa, K.

2017-12-01

Destructive natural disasters such as earthquakes and tsunamis have occurred frequently in the world. For instance, 2004 Sumatra Earthquake in Indonesia, 2008 Wenchuan Earthquake in China, 2010 Chile Earthquake and 2011 Tohoku Earthquake in Japan etc., these earthquakes generated very severe damages. For the reduction and mitigation of damages by destructive natural disasters, early detection of natural disasters and speedy and proper evacuations are indispensable. And hardware and software developments/preparations for reduction and mitigation of natural disasters are quite important. In Japan, DONET as the real time monitoring system on the ocean floor is developed and deployed around the Nankai trough seismogenic zone southwestern Japan. So, the early detection of earthquakes and tsunamis around the Nankai trough seismogenic zone will be expected by DONET. The integration of the real time data and advanced simulation researches will lead to reduce damages, however, in the resilience society, the resilience methods will be required after disasters. Actually, methods on restorations and revivals are necessary after natural disasters. We would like to propose natural disaster mitigation science for early detections, evacuations and restorations against destructive natural disasters. This means the resilience society. In natural disaster mitigation science, there are lots of research fields such as natural science, engineering, medical treatment, social science and literature/art etc. Especially, natural science, engineering and medical treatment are fundamental research fields for natural disaster mitigation, but social sciences such as sociology, geography and psychology etc. are very important research fields for restorations after natural disasters. Finally, to realize and progress disaster mitigation science, human resource cultivation is indispensable. We already carried out disaster mitigation science under `new disaster mitigation research project on Mega thrust earthquakes around Nankai/Ryukyu subduction zone', and `SATREPS project of earthquake and tsunami disaster mitigation in the Marmara region and disaster education in Turkey'. Furthermore, we have to progress the natural disaster mitigation science against destructive natural disaster in the near future.

10 th of July, 1894 İstanbul Earthquake (Marmara Sea, Turkey)

NASA Astrophysics Data System (ADS)

Yaltırak, Cenk; Şahin, Murat

2017-04-01

The sea of Marmara is a region with the longest historical earthquake record of our planet. The earthquake of 10 July 1894 in Istanbul is the last earthquake of the historical period before the beginning of the instrumental period in the region. The magnitude and location of this earthquake and also its relationship with the North Anatolian Fault should be discussed in literature. Previous studies have not fully analyzed the historical data of 1894 earthquakes. For this reason, conflicting views are put forward regarding an earthquake in Marmara in the future. According to the historical records, the major damage was in the Istanbul Peninsula, Avcılar, Adalar, Karamürsel and Yalova. Due to its formation properties, it was effective in remote areas (İzmit, Gölcük, Adapazarı). It is clear that the most damage was in Old Istanbul and Prince Island. The tension cracks in different directions were observed in Heybeliada, Büyükada and Burgazada. There are observations to be interpreted as a tsunami wave about one and a half meter-height between Avcılar and Kartal. The submarine telegraph line extending from Kartal to Marmara Sea was broken at three points in the east of Büyükada. According to the damage assessment after the earthquake and other observations, it is understood that this earthquake was along the Adalar Fault. When considering seismic and multibeam data, it is apparent that the Adalar Fault was composed of echolon segments. The submarine landslides were mapped in front of the fault scarp. The Adalar Fault is a 45 km-long, 80o SW-dipping right-lateral normal oblique fault. The tsunami scenarios that we modelld along this fault are compatible with historical observations along the coast of İstanbul. Our GIS-based intensity scenario shows that the magnitude of the 1894 Istanbul Earthquake is Mw 7.

Feasibility of Twitter Based Earthquake Characterization From Analysis of 32 Million Tweets: There's Got to be a Pony in Here Somewhere!

NASA Astrophysics Data System (ADS)

Earle, P. S.; Guy, M. R.; Smoczyk, G. M.; Horvath, S. R.; Jessica, T. S.; Bausch, D. B.

2014-12-01

The U.S. Geological Survey (USGS) operates a real-time system that detects earthquakes using only data from Twitter—a service for sending and reading public text-based messages of up to 140 characters. The detector algorithm scans for significant increases in tweets containing the word "earthquake" in several languages and sends internal alerts with the detection time, representative tweet texts, and the location of the population center where most of the tweets originated. It has been running in real-time for over two years and finds, on average, two or three felt events per day, with a false detection rate of 9%. The main benefit of the tweet-based detections is speed, with most detections occurring between 20 and 120 seconds after the earthquake origin time. This is considerably faster than seismic detections in poorly instrumented regions of the world. The detections have reasonable coverage of populated areas globally. The number of Twitter-based detections is small compared to the number of earthquakes detected seismically, and only a rough location and qualitative assessment of shaking can be determined based on Tweet data alone. However, the Twitter-based detections are generally caused by widely felt events in populated urban areas that are of more immediate interest than those with no human impact. We will present a technical overview of the system and investigate the potential for rapid characterization of earthquake damage and effects using the 32 million "earthquake" tweets that the system has so far amassed. Initial results show potential for a correlation between characteristic responses and shaking level. For example, tweets containing the word "terremoto" were common following the MMI VII shaking produced by the April 1, 2014 M8.2 Iquique, Chile earthquake whereas a widely-tweeted deep-focus M5.2 north of Santiago, Chile on April 4, 2014 produced MMI VI shaking and almost exclusively "temblor" tweets. We are also investigating the use of other social media such as Instagram to obtain rapid images of earthquake-related damage. An Instagram search following the damaging M6.9 earthquake near the Mexico, Guatemala boarder on July 7, 2014 reveled half a dozen unconfirmed images of damage; the first posted 15 minutes after the event.

Simulation and monitoring tools to protect disaster management facilities against earthquakes

NASA Astrophysics Data System (ADS)

Saito, Taiki

2017-10-01

The earthquakes that hit Kumamoto Prefecture in Japan on April 14 and 16, 2016 severely damaged over 180,000 houses, including over 8,000 that were completely destroyed and others that were partially damaged according to the Cabinet Office's report as of November 14, 2016 [1]. Following these earthquakes, other parts of the world have been struck by earthquakes including Italy and New Zealand as well as the central part of Tottori Prefecture in October, where the earthquake-induced collapse of buildings has led to severe damage and casualties. The earthquakes in Kumamoto Prefecture, in fact, damaged various disaster management facilities including Uto City Hall, which significantly hindered the city's evacuation and recovery operations. One of the most crucial issues in times of disaster is securing the functions of disaster management facilities such as city halls, hospitals and fire stations. To address this issue, seismic simulations are conducted on the East and the West buildings of Toyohashi City Hall using the analysis tool developed by the author, STERA_3D, with the data of the ground motion waveform prediction for the Nankai Trough earthquake provided by the Ministry of Land, Infrastructure, Transport and Tourism. As the result, it was found that the buildings have sufficient earthquake resistance. It turned out, however, that the west building is at risk for wall cracks or ceiling panel's collapse while in the east building, people would not be able to stand through the strong quakes of 7 on the seismic intensity scale and cabinets not secured to the floors or walls would fall over. Additionally, three IT strong-motion seismometers were installed in the city hall to continuously monitor vibrations. Every five minutes, the vibration data obtained by the seismometers are sent to the computers in Toyohashi University of Technology via the Internet for the analysis tools to run simulations in the cloud. If an earthquake strikes, it is able to use the results of the simulations to assess whether it is safe to continue using the buildings. There is a plan to implement more measures against earthquakes, for example by having additional monitoring locations including fire stations and evacuation facilities, and installing a dedicated line for disaster prevention. Accumulating real-time data in the cloud can also improve the accuracy of the simulations.

A quick earthquake disaster loss assessment method supported by dasymetric data for emergency response in China

NASA Astrophysics Data System (ADS)

Xu, Jinghai; An, Jiwen; Nie, Gaozong

2016-04-01

Improving earthquake disaster loss estimation speed and accuracy is one of the key factors in effective earthquake response and rescue. The presentation of exposure data by applying a dasymetric map approach has good potential for addressing this issue. With the support of 30'' × 30'' areal exposure data (population and building data in China), this paper presents a new earthquake disaster loss estimation method for emergency response situations. This method has two phases: a pre-earthquake phase and a co-earthquake phase. In the pre-earthquake phase, we pre-calculate the earthquake loss related to different seismic intensities and store them in a 30'' × 30'' grid format, which has several stages: determining the earthquake loss calculation factor, gridding damage probability matrices, calculating building damage and calculating human losses. Then, in the co-earthquake phase, there are two stages of estimating loss: generating a theoretical isoseismal map to depict the spatial distribution of the seismic intensity field; then, using the seismic intensity field to extract statistics of losses from the pre-calculated estimation data. Thus, the final loss estimation results are obtained. The method is validated by four actual earthquakes that occurred in China. The method not only significantly improves the speed and accuracy of loss estimation but also provides the spatial distribution of the losses, which will be effective in aiding earthquake emergency response and rescue. Additionally, related pre-calculated earthquake loss estimation data in China could serve to provide disaster risk analysis before earthquakes occur. Currently, the pre-calculated loss estimation data and the two-phase estimation method are used by the China Earthquake Administration.

Rapid damage mapping for the 2015 M7.8 Gorkha earthquake using synthetic aperture radar data from COSMO-SkyMed and ALOS-2 satellites

USGS Publications Warehouse

Yun, Sang-Ho; Hudnut, Kenneth W.; Owen, Susan; Webb, Frank; Simons, Mark; Sacco, Patrizia; Gurrola, Eric; Manipon, Gerald; Liang, Cunren; Fielding, Eric; Milillo, Pietro; Hua, Hook; Coletta, Alessandro

2015-01-01

The 25 April 2015 Mw 7.8 Gorkha earthquake caused more than 8000 fatalities and widespread building damage in central Nepal. The Italian Space Agency’s COSMO–SkyMed Synthetic Aperture Radar (SAR) satellite acquired data over Kathmandu area four days after the earthquake and the Japan Aerospace Exploration Agency’s Advanced Land Observing Satellite-2 SAR satellite for larger area nine days after the mainshock. We used these radar observations and rapidly produced damage proxy maps (DPMs) derived from temporal changes in Interferometric SAR coherence. Our DPMs were qualitatively validated through comparison with independent damage analyses by the National Geospatial-Intelligence Agency and the United Nations Institute for Training and Research’s United Nations Operational Satellite Applications Programme, and based on our own visual inspection of DigitalGlobe’s WorldView optical pre- versus postevent imagery. Our maps were quickly released to responding agencies and the public, and used for damage assessment, determining inspection/imaging priorities, and reconnaissance fieldwork.

Field survey of earthquake effects from the magnitude 4.0 southern Maine earthquake of October 16, 2012

USGS Publications Warehouse

Amy L. Radakovich,; Alex J. Fergusen,; Boatwright, John

2016-06-02

The magnitude 4.0 earthquake that occurred on October 16, 2012, near Hollis Center and Waterboro in southwestern Maine surprised and startled local residents but caused only minor damage. A two-person U.S. Geological Survey (USGS) team was sent to Maine to conduct an intensity survey and document the damage. The only damage we observed was the failure of a chimney and plaster cracks in two buildings in East and North Waterboro, 6 kilometers (km) west of the epicenter. We photographed the damage and interviewed residents to determine the intensity distribution in the epicentral area. The damage and shaking reports are consistent with a maximum Modified Mercalli Intensity (MMI) of 5–6 for an area 1–8 km west of the epicenter, slightly higher than the maximum Community Decimal Intensity (CDI) of 5 determined by the USGS “Did You Feel It?” Web site. The area of strong shaking in East Waterboro corresponds to updip rupture on a fault plane that dips steeply east. 

Geotechnical and structural lessons learnt from the aqaba (ml = 6.2) earthquake of Novemeber 22, 1995

NASA Astrophysics Data System (ADS)

Al-Homoud, A.

2003-04-01

This study reflects in some details on the following aspects related to the region: geological and tectonic setting, seismicity, swarms activity data base and seismic hazard assessment. Moreover, it documents the following aspects of the November 22, 1995 earthquake: tectonic, seismological, instrumental seismic data, strong motion recordings and response spectral and local site effect analysis, geotechnical effects and structural observations in the region affected by the earthquake. The study identifies local site effects on structural damages. These observations were analyzed in connection with the observed damages. It is concluded that liquefaction potential, effect of soil column, poor quality of construction, and underestimating the design base shear are the main factors that contributed to the observed damages. Practical recommendations are suggested for the authorities to avoid similar damages in newly constructed buildings and lifelines during future similar earthquakes. On November 22, 1995, the Gulf of Aqaba region was shaken by a strong earthquake that was felt from Sudan to Lebanon. The epicenter was located in the gulf water midway between the Egyptian cities of Dahab and Nuweiba on the Sinai Peninsula. The main shock was followed by thousands of aftershocks, the strongest of which occurred on November 23, 1995 with a local magnitude of 5.4. The main shock triggered strong motion accelerographs belonging to the Jordanian and Israeli networks at Aqaba and Eilat cities, respectively. Structural damages to buildings and lifeline systems were reported in several cities located along the gulf coast including Aqaba in Jordan,Haql in Saudi Arabia, Sharm Al-Sheik, Dahab and Nuweiba in Egypt, and Eilat in Israel. In the city of Nuweiba, located 40 km north of the epicenter, surveyed damage suggests that the horizontal peak ground was in the range of 0.16 g - 0.25 g. Strong motion records indicated that at the port cit of Eilat (a distance of 92.7 km from the epicenter) maximum peak ground acceleration was 0.110 g. Almost, similar values were obtained at the Jordanian side. In general, buildings and lifeline systems in the epicentral region performed poorly during the earthquake .

Earthquake Damage Assessment over Port-au-Prince (Haiti) by Fusing Optical and SAR Data

NASA Astrophysics Data System (ADS)

Romaniello, V.; Piscini, A.; Bignami, C.; Anniballe, R.; Pierdicca, N.; Stramondo, S.

2016-08-01

This work proposes methodologies aiming at evaluating the sensitivity of optical and SAR change features obtained from satellite images with respect to the damage grade. The proposed methods are derived from the literature ([1], [2], [3], [4]) and the main novelty concerns the estimation of these change features at object scale.The test case is the Mw 7.0 earthquake that hit Haiti on January 12, 2010.The analysis of change detection indicators is based on ground truth information collected during a post- earthquake survey. We have generated the damage map of Port-au-Prince by considering a set of polygons extracted from the open source Open Street Map geo- database. The resulting damage map was calculated in terms of collapse ratio [5].We selected some features having a good sensitivity with damage at object scale [6]: the Normalised Difference Index, the Kullback-Libler Divergence, the Mutual Information and the Intensity Correlation Difference.The Naive Bayes and the Support Vector Machine classifiers were used to evaluate the goodness of these features. The classification results demonstrate that the simultaneous use of several change features from EO observations can improve the damage estimation at object scale.

Rapid building damage assessment system using mobile phone technology

NASA Astrophysics Data System (ADS)

Cimellaro, Gian Paolo; Scura, G.; Renschler, C. S.; Reinhorn, A. M.; Kim, H. U.

2014-09-01

One common scenario during disasters such as earthquakes is that the activity of damage field reconnaissance on site is not well-coordinated. For example in Italy the damage assessment of structures after an earthquake is managed from the Italian Emergency Authority, using printed forms (AeDES) which are filled by experts on site generating a lot of confusion in filling and transferring the forms to the Disaster Management Operative Center. Because of this, the paper explores the viability of using mobile communication technologies (smart phones) and the Web to develop response systems that would aid communities after a major disaster, providing channels for allowing residents and responders of uploading and distributing information, related to structural damages coordinating the damage field reconnaissance. A mobile application that can be run by residents on smart phones has been developed, to give an initial damage evaluation of the area, which is going to be very useful when resources (e.g. the number of experts is limited). The mobile application has been tested for the first time during 2012 Emilia earthquake to enhance the emergency response, showing the efficiency of the proposed method in statistical terms comparing the proposed procedure with the standard procedure.

Monitoring the Dead Sea Region by Multi-Parameter Stations

NASA Astrophysics Data System (ADS)

Mohsen, A.; Weber, M. H.; Kottmeier, C.; Asch, G.

2015-12-01

The Dead Sea Region is an exceptional ecosystem whose seismic activity has influenced all facets of the development, from ground water availability to human evolution. Israelis, Palestinians and Jordanians living in the Dead Sea region are exposed to severe earthquake hazard. Repeatedly large earthquakes (e.g. 1927, magnitude 6.0; (Ambraseys, 2009)) shook the whole Dead Sea region proving that earthquake hazard knows no borders and damaging seismic events can strike anytime. Combined with the high vulnerability of cities in the region and with the enormous concentration of historical values this natural hazard results in an extreme earthquake risk. Thus, an integration of earthquake parameters at all scales (size and time) and their combination with data of infrastructure are needed with the specific aim of providing a state-of-the-art seismic hazard assessment for the Dead Sea region as well as a first quantitative estimate of vulnerability and risk. A strong motivation for our research is the lack of reliable multi-parameter ground-based geophysical information on earthquakes in the Dead Sea region. The proposed set up of a number of observatories with on-line data access will enable to derive the present-day seismicity and deformation pattern in the Dead Sea region. The first multi-parameter stations were installed in Jordan, Israel and Palestine for long-time monitoring. All partners will jointly use these locations. All stations will have an open data policy, with the Deutsches GeoForschungsZentrum (GFZ, Potsdam, Germany) providing the hard and software for real-time data transmission via satellite to Germany, where all partners can access the data via standard data protocols.

Landslides and megathrust splay faults captured by the late Holocene sediment record of eastern Prince William Sound, Alaska

USGS Publications Warehouse

Finn, S.P.; Liberty, Lee M.; Haeussler, Peter J.; Pratt, Thomas L.

2015-01-01

We present new marine seismic‐reflection profiles and bathymetric maps to characterize Holocene depositional patterns, submarine landslides, and active faults beneath eastern and central Prince William Sound (PWS), Alaska, which is the eastern rupture patch of the 1964 Mw 9.2 earthquake. We show evidence that submarine landslides, many of which are likely earthquake triggered, repeatedly released along the southern margin of Orca Bay in eastern PWS. We document motion on reverse faults during the 1964 Great Alaska earthquake and estimate late Holocene slip rates for these growth faults, which splay from the subduction zone megathrust. Regional bathymetric lineations help define the faults that extend 40–70 km in length, some of which show slip rates as great as 3.75  mm/yr. We infer that faults mapped below eastern PWS connect to faults mapped beneath central PWS and possibly onto the Alaska mainland via an en echelon style of faulting. Moderate (Mw>4) upper‐plate earthquakes since 1964 give rise to the possibility that these faults may rupture independently to potentially generate Mw 7–8 earthquakes, and that these earthquakes could damage local infrastructure from ground shaking. Submarine landslides, regardless of the source of initiation, could generate local tsunamis to produce large run‐ups along nearby shorelines. In a more general sense, the PWS area shows that faults that splay from the underlying plate boundary present proximal, perhaps independent seismic sources within the accretionary prism, creating a broad zone of potential surface rupture that can extend inland 150 km or more from subduction zone trenches.

Earthquakes, November-December 1992

USGS Publications Warehouse

Person, W.J.

1993-01-01

There were two major earthquakes (7.0≤M<8.0) during the last two months of the year, a magntidue 7.5 earthquake on December 12 in the Flores region, Indonesia, and a magnitude 7.0 earthquake on December 20 in the Banda Sea. Earthquakes caused fatalities in China and Indonesia. The greatest number of deaths (2,500) for the year occurred in Indonesia. In Switzerland, six people were killed by an accidental explosion recoreded by seismographs. In teh United States, a magnitude 5.3 earthquake caused slight damage at Big Bear in southern California. 

Automatic Blocked Roads Assessment after Earthquake Using High Resolution Satellite Imagery

NASA Astrophysics Data System (ADS)

Rastiveis, H.; Hosseini-Zirdoo, E.; Eslamizade, F.

2015-12-01

In 2010, an earthquake in the city of Port-au-Prince, Haiti, happened quite by chance an accident and killed over 300000 people. According to historical data such an earthquake has not occurred in the area. Unpredictability of earthquakes has necessitated the need for comprehensive mitigation efforts to minimize deaths and injuries. Blocked roads, caused by debris of destroyed buildings, may increase the difficulty of rescue activities. In this case, a damage map, which specifies blocked and unblocked roads, can be definitely helpful for a rescue team. In this paper, a novel method for providing destruction map based on pre-event vector map and high resolution world view II satellite images after earthquake, is presented. For this purpose, firstly in pre-processing step, image quality improvement and co-coordination of image and map are performed. Then, after extraction of texture descriptor from the image after quake and SVM classification, different terrains are detected in the image. Finally, considering the classification results, specifically objects belong to "debris" class, damage analysis are performed to estimate the damage percentage. In this case, in addition to the area objects in the "debris" class their shape should also be counted. The aforementioned process are performed on all the roads in the road layer.In this research, pre-event digital vector map and post-event high resolution satellite image, acquired by Worldview-2, of the city of Port-au-Prince, Haiti's capital, were used to evaluate the proposed method. The algorithm was executed on 1200×800 m2 of the data set, including 60 roads, and all the roads were labelled correctly. The visual examination have authenticated the abilities of this method for damage assessment of urban roads network after an earthquake.

Earthquake!

ERIC Educational Resources Information Center

Hernandez, Hildo

2000-01-01

Examines the types of damage experienced by California State University at Northridge during the 1994 earthquake and what lessons were learned in handling this emergency are discussed. The problem of loose asbestos is addressed. (GR)

The Determination Method of Extreme Earthquake Disaster Area Based on the Dust Detection Result from GF-4 Data

NASA Astrophysics Data System (ADS)

Dou, A.; Ding, L.; Chen, M.; Wang, X.

2018-04-01

The remote sensing has played an important role in many earthquake emergencies by rapidly providing the building damage, road damage, landslide and other disaster information. The earthquake in the mountains often caused to the loosening of the mountains and the blowing of the dust in the epicentre area. The dust particles are more serious in the epicentre area than the other disaster area. Basis on the analysis of abnormal spectrum characteristics, the dust detection methods from medium and high resolutions satellite imagery are studied in order to determinate the extreme earthquake disaster area. The results indicate the distribution of extreme disaster can be acquired using the dust detection information from imagery, which can provide great help for disaster intensity assessment.

Geomorphic and geologic controls of geohazards induced by Nepal’s 2015 Gorkha earthquake

USGS Publications Warehouse

Kargel, J.S.; Leonard, G.J.; Shugar, D. H.; Haritashya, U. K.; Bevington, A.; Fielding, E.J.; Fujita, K.; Geertsema, M.; Miles, E. S.; Steiner, J.; Anderson, E.; Bajracharya, S.; Bawden, G.W.; Breashears, D. F.; Byers, A.; Collins, B.; Dhital, M. R.; Donnellan, A.; Evans, T. L.; Geai, M. L.; Glasscoe, M. T.; Green, D.; Gurung, D. R.; Heijenk, R.; Hilborn, A.; Hudnut, K.; Huyck, C.; Immerzeel, W. W.; Liming, Jiang; Jibson, R.; Kaab, A.; Khanal, N. R.; Kirschbaum, D.; Kraaijenbrink, P. D. A.; Lamsal, D.; Shiyin, Liu; Mingyang, Lv; McKinney, D.; Nahirnick, N. K.; Zhuotong, Nan; Ojha, S.; Olsenholler, J.; Painter, T.H.; Pleasants, M.; Pratima, K. C.; Yuan, Q. I.; Raup, B.H.; Regmi, D.; Rounce, D. R.; Sakai, A.; Donghui, Shangguan; Shea, J. M.; Shrestha, A. B.; Shukla, A.; Stumm, D.; van der Kooij, M.; Voss, K.; Xin, Wang; Weihs, B.; Lizong, Wu; Xiaojun, Yao; Yoder, M. R.; Young, N.

2016-01-01

The Gorkha earthquake (magnitude 7.8) on 25 April 2015 and later aftershocks struck South Asia, killing ~9000 people and damaging a large region. Supported by a large campaign of responsive satellite data acquisitions over the earthquake disaster zone, our team undertook a satellite image survey of the earthquakes’ induced geohazards in Nepal and China and an assessment of the geomorphic, tectonic, and lithologic controls on quake-induced landslides. Timely analysis and communication aided response and recovery and informed decision-makers. We mapped 4312 coseismic and postseismic landslides. We also surveyed 491 glacier lakes for earthquake damage but found only nine landslide-impacted lakes and no visible satellite evidence of outbursts. Landslide densities correlate with slope, peak ground acceleration, surface downdrop, and specific metamorphic lithologies and large plutonic intrusions.

Spatial and temporal variability in rates of landsliding in seismically active mountain ranges

NASA Astrophysics Data System (ADS)

Parker, R.; Petley, D.; Rosser, N.; Densmore, A.; Gunasekera, R.; Brain, M.

2012-04-01

Where earthquake and precipitation driven disasters occur in steep, mountainous regions, landslides often account for a large proportion of the associated damage and losses. This research addresses spatial and temporal variability in rates of landslide occurrence in seismically active mountain ranges as a step towards developing better regional scale prediction of losses in such events. In the first part of this paper we attempt to explain reductively the variability in spatial rates of landslide occurrence, using data from five major earthquakes. This is achieved by fitting a regression-based conditional probability model to spatial probabilities of landslide occurrence, using as predictor variables proxies for spatial patterns of seismic ground motion and modelled hillslope stability. A combined model for all earthquakes performs well in hindcasting spatial probabilities of landslide occurrence as a function of readily-attainable spatial variables. We present validation of the model and demonstrate the extent to which it may be applied globally to derive landslide probabilities for future earthquakes. In part two we examine the temporal behaviour of rates of landslide occurrence. This is achieved through numerical modelling to simulate the behaviour of a hypothetical landscape. The model landscape is composed of hillslopes that continually weaken, fail and reset in response to temporally-discrete forcing events that represent earthquakes. Hillslopes with different geometries require different amounts of weakening to fail, such that they fail and reset at different temporal rates. Our results suggest that probabilities of landslide occurrence are not temporally constant, but rather vary with time, irrespective of changes in forcing event magnitudes or environmental conditions. Various parameters influencing the magnitude and temporal patterns of this variability are identified, highlighting areas where future research is needed. This model has important implications for landslide hazard and risk analysis in mountain areas as existing techniques usually assume that susceptibility to failure does not change with time.

NRIAG's Effort to Mitigate Earthquake Disasters in Egypt Using GPS and Seismic Data

NASA Astrophysics Data System (ADS)

Mahmoud, Salah

It has been estimated that, during historical time more than 50 million people have lost their lives in earthquakes during ground shaking, such as soil amplification and/or liquefaction, landslides and tsunamis or its immediate aftereffects, as fires. The distribution of population takes generally no account of earthquake risk, at least on a large scale. An earthquake may be large but not destructive, on the other hand, an earthquake may be destructive but not large. The absence of correlation is due to the fact that, great number of other factors entering into consideration: first of all, the location of the earthquake in relation to populated areas, also soil conditions and building constructions. Soil liquefaction has been identified as the underlying phenomenon for many ground failures, settlements and lateral spreads, which are a major cause of damage to soil structures and building foundations in many events. Egypt is suffered a numerous of destructive earthquakes as well as Kalabsha earthquake (1981, Mag 5.4) near Aswan city and the High dam, Dahshour earthquake (1992, Mag 5.9) near Cairo city and Aqaba earthquake (1995, Mag 7.2). As the category of earthquake damage includes all the phenomena related to the direct and indirect damages, the Egyptian authorities do a great effort to mitigate the earthquake disasters. The seismicity especially at the zones of high activity is investigated in details in order to obtain the active source zones not only by the Egyptian National Seismic Network (ENSN) but also by the local seismic networks at, Aswan, Hurghada, Aqaba, Abu Dabbab and Dabbaa. On the other hand the soil condition, soil amplification, soil structure interaction, liquefaction and seismic hazard are carried out in particular the urbanized areas and the region near the source zones. All these parameters are integrated to obtain the Egyptian building code which is valid to construct buildings resist damages and consequently mitigate the earthquake disasters. Since the year of 1994 till now, the geodetic observations by means of Global Positioning System (GPS) were applied instead of the terrestrial ones to cover some other regions of the country. These regions include Sinai, Gulf of Suez, Greater Cairo, Aswan and the Middle part on the River Nile. Data adjustment and analysis of the repeated GPS campaigns from the different networks prevailed significant movements which may help in more understanding the geodynamics of these regions. In the meantime, GPS measurements of crustal motions for 189 sites extending east-west from the Caucasus Mountains to the Adriatic Sea and north-south from the southern edge of the Eurasian plate to the northern edge of the African plate were carried out for the period from 1988 till 2005. Estimate of plate motions at stations located at different plates were determined.

Permeability, storage and hydraulic diffusivity controlled by earthquakes

NASA Astrophysics Data System (ADS)

Brodsky, E. E.; Fulton, P. M.; Xue, L.

2016-12-01

Earthquakes can increase permeability in fractured rocks. In the farfield, such permeability increases are attributed to seismic waves and can last for months after the initial earthquake. Laboratory studies suggest that unclogging of fractures by the transient flow driven by seismic waves is a viable mechanism. These dynamic permeability increases may contribute to permeability enhancement in the seismic clouds accompanying hydraulic fracking. Permeability enhancement by seismic waves could potentially be engineered and the experiments suggest the process will be most effective at a preferred frequency. We have recently observed similar processes inside active fault zones after major earthquakes. A borehole observatory in the fault that generated the M9.0 2011 Tohoku earthquake reveals a sequence of temperature pulses during the secondary aftershock sequence of an M7.3 aftershock. The pulses are attributed to fluid advection by a flow through a zone of transiently increased permeability. Directly after the M7.3 earthquake, the newly damaged fault zone is highly susceptible to further permeability enhancement, but ultimately heals within a month and becomes no longer as sensitive. The observation suggests that the newly damaged fault zone is more prone to fluid pulsing than would be expected based on the long-term permeability structure. Even longer term healing is seen inside the fault zone of the 2008 M7.9 Wenchuan earthquake. The competition between damage and healing (or clogging and unclogging) results in dynamically controlled permeability, storage and hydraulic diffusivity. Recent measurements of in situ fault zone architecture at the 1-10 meter scale suggest that active fault zones often have hydraulic diffusivities near 10-2 m2/s. This uniformity is true even within the damage zone of the San Andreas fault where permeability and storage increases balance each other to achieve this value of diffusivity over a 400 m wide region. We speculate that fault zones may evolve to a preferred diffusivity in a dynamic equilibrium.

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.

Effects of the earthquake of March 27, 1964, on the communities of Kodiak and nearby islands: Chapter F in The Alaska earthquake, March 27, 1964: effects on communities

USGS Publications Warehouse

Kachadoorian, Reuben; Plafker, George

1967-01-01

The great earthquake (Richter magnitude of 8.4–8.5) that struck south-central Alaska at 5:36 p.m., Alaska standard time, on March 27, 1964 (03:36, March 28, Greenwich mean time), was felt in every community on Kodiak Island and the nearby islands. It was the most severe earthquake to strike this part of Alaska in modern time, and took the lives of 18 persons in the area by drowning; this includes two in Kodiak and three at Kaguyak. Property damage and loss of income to the communities is estimated at more than $45 million. The largest community, Kodiak, had the greatest loss from the earthquake. Damage was caused chiefly by 5.6 feet of tectonic subsidence and a train of 10 seismic sea waves that inundated the low-lying areas of the town. The seismic sea waves destroyed all but one of the docking facilities and more than 215 structures; many other structures were severely damaged. The waves struck the town during the evening hours of March 27 and early morning hours of March 28. They moved from the southwest and northeast: and reached their maximum height of 20–30 feet above mean lower low water at Shahafka Cove between 11:00 and 11:45 p.m., March 27. The violently destructive seismic sea waves not only severely damaged homes, shops, and naval-station structures but also temporarily crippled the fishing industry in Kodiak by destroying the processing plants and most of the fishing vessels. The waves scoured out 10 feet of sediments in the channel between Kodiak Island and Near Island and exposed bedrock. This bedrock presented a major post-earthquake construction problem because no sediments remained into which piles could be driven for foundations of waterfront facilities. Because of tectonic subsidence, high tides now flood Mission and Potatopatch Lakes which, before the earthquake, had not been subject to tidal action. The subsidence also accelerated erosion of the unconsolidated sediments along the shoreline in the city of Kodiak. Seismic shaking lasted 4½–5½ minutes at Kodiak and had a rolling motion. Inasmuch as most of Kodiak is underlain by bedrock or by only a thin veneer of unconsolidated sediments, very little if any damage occurred from ground motion or seismic shaking. The ground motion, however, did cause a massive short circuit and power failure at Kodiak. The Kodiak Naval Station, 5 miles southwest of Kodiak, was also severely damaged by the earthquake. The station was inundated by at least 10 seismic sea waves which reached a maximum height of 25 feet above post-earthquake mean lower low water between 11:16 and 11:34 p.m. on March 27, 1964. The first seismic sea wave that inundated the station did not do severe damage because it behaved much like a rapid rise of tide, but the subsequent and more violent waves destroyed most of the docking facilities and several other shoreline structures. The waves struck the station from the southwest and from the east. The shoreline structures that were not destroyed required rehabilitation because the 5.6 feet of tectonic subsidence put them under water during the highest tides. Furthermore the subsidence accelerated erosion during high tide of the soft unconsolidated sediments and fill in the low-lying areas of the station. Seismic shaking did little damage to the station housing facility, but it was responsible for compaction of sediments, lateral displacement of a seawall, and the development of fissures in the aircraft parking area. The ground motion was as south-southeast–north-northwest to north-south in direction. An unusual case of radioactive contamination was reported at the naval station. The inundating seismic sea waves entered a building in which radionuclides were stored. The contamination was restricted to the building only, however, and did not spread throughout the station. Afognak was abandoned because of the extensive damage incurred from tectonic subsistence and seismic sea waves. The seismic effects, estimated Mercalli intensity VI-VII, did not directly cause any significant property damage at Afognak Serious long-term damage, however, resulted from tectonic subsidence estimated to be from 3½ to 5½ feet. The subsidence has resulted in rapid erosion of the coast, landward shift and building up of bench berms to the new higher sea levels, and flooding of extensive low-lying areas behind the barrier beaches. Inundation of low-lying parts of the village by a train of seismic sea waves having maximum heights of 10.8 feet above post-earthquake tide level (14.5 ft above post-earthquake mean lower low water) caused losses of about half a million dollars to homes, vehicles, bridges, and personal possessions. Uzinki was damaged by tectonic subsidence and seismic sea waves. No significant damage resulted from the ground motion during the earthquake; the Mercalli intensity was about VI. However, tectonic subsidence, estimated to be 5 feet, caused inundation of a narrow zone along the waterfront. Structures and vessels were damaged as a result of the seismic sea waves that repeatedly flooded the waterfront area after the earthquake. Old Harbor was damaged by seismic shock, subsidence, and seismic sea waves. The tremors, which had a Mercalli intensity estimated at VII-VIII, toppled two concrete-block chimneys, cracked interior walls, and caused minor breakage of personal property in the homes. Regional tectonic subsidence and superficial subsidence of the unconsolidated deposits on which the village is situated apparently caused incursion of salt water into the school well. A quarter of million yards of fill was required to raise the waterfront areas to their pre-earthquake elevations relative to sea level. Seismic sea waves having a maximum runup of about 12 feet above tide level (16 ft above post-earthquake mean lower low water) destroyed 34 of the 35 residences in the village and presumably drowned one man who lived immediately across the strait from Old Harbor. At Kaguyak, seismic sea waves having a maximum runup of about 25 feet above mean lower low water carried away all 10 buildings in the village, took three lives, and damaged an unknown number of fishing vessels. The village site has been abandoned. The communities of Akhiok, Karluk, and Larsen Bay were virtually undamaged by the earthquake tremors, which had estimated Mercalli intensities of VI-VII, but tectonic subsidence of about 2–2½ feet at Larsen Bay made it necessary to raise the cannery dock level at an estimated cost of $80,000.

Atmospheric Baseline Monitoring Data Losses Due to the Samoa Earthquake

NASA Astrophysics Data System (ADS)

Schnell, R. C.; Cunningham, M. C.; Vasel, B. A.; Butler, J. H.

2009-12-01

The National Oceanic and Atmospheric Administration (NOAA) operates an Atmospheric Baseline Observatory at Cape Matatula on the north-eastern point of American Samoa, opened in 1973. The manned observatory conducts continuous measurements of a wide range of climate forcing and atmospheric composition data including greenhouse gas concentrations, solar radiation, CFC and HFC concentrations, aerosols and ozone as well as less frequent measurements of many other parameters. The onset of September 29, 2009 earthquake is clearly visible in the continuous data streams in a variety of ways. The station electrical generator came online when the Samoa power grid failed so instruments were powered during and subsequent to the earthquake. Some instruments ceased operation in a spurt of spurious data followed by silence. Other instruments just stopped sending data abruptly when the shaking from the earthquake broke a data or power links, or an integral part of the instrument was damaged. Others survived the shaking but were put out of calibration. Still others suffered damage after the earthquake as heaters ran uncontrolled or rotating shafts continued operating in a damaged environment grinding away until they seized up or chewed a new operating space. Some instruments operated as if there was no earthquake, others were brought back online within a few days. Many of the more complex (and in most cases, most expensive) instruments will be out of service, some for at least 6 months or more. This presentation will show these results and discuss the impact of the earthquake on long-term measurements of climate forcing agents and other critical climate measurements.

Investigating the March 28th 1875 and the September 20th 1920 earthquakes/tsunamis of the Southern Vanuatu arc, offshore Loyalty Islands, New Caledonia

NASA Astrophysics Data System (ADS)

Ioualalen, Mansour; Pelletier, Bernard; Solis Gordillo, Gabriela

2017-07-01

New Caledonia's Loyalty Islands are located in the southwest region of the Pacific ocean in the highly seismogenic southern Vanuatu subduction zone and therefore may be subject to devastating local tsunamis. Over the past 150 years, two large tsunamis were triggered by major earthquakes on March 28th 1875 and September 20th 1920. In this study, we use historical observations of these tsunamis (mostly in the form of testimonials), earthquake scenarios, and tsunami modeling to derive the magnitudes of these earthquakes, as well as tsunami runup and inundation maps. Assuming that these earthquakes were located on the interplate megathrust zone, the 1875 earthquake's magnitude was Mw8.1-8.2 and the 1920 event's magnitude was Mw7.5-7.8. The tsunami damage inflicted on the Lifou and Maré islands was approximately proportional to these magnitudes, with Maré being less impacted due to favorable wave directivity. Damage at Ouvéa island may have varied irregularly with the magnitude due to the effects of resonance. This study demonstrates that the quantitative characteristics of historical tsunamigenic earthquakes may be derived from qualitative estimates of tsunami runup.

NEIC; the National Earthquake Information Center

USGS Publications Warehouse

Masse, R.P.; Needham, R.E.

1989-01-01

At least 9,500 people were killed, 30,000 were injured and 100,000 were left homeless by this earthquake. According to some unconfirmed reports, the death toll from this earthquake may have been as high as 35,000. this earthquake is estimated to have seriously affected an area of 825,000 square kilometers, caused between 3 and 4 billion dollars in damage, and been felt by 20 million people. 

Faulting, damage, and intensity in the Canyondam earthquake of May 23, 2013

USGS Publications Warehouse

Chapman, K.; Gold, M.B.; Boatwright, John; Sipe, J.; Quitoriano, V.; Dreger, D.; Hardebeck, Jeanne

2016-09-23

On Thursday evening, May 23, 2013 (0347 May 24 UTC), a moment magnitude (Mw) = 5.7 earthquake occurred northeast of Canyondam, California. A two-person team of U.S. Geological Survey scientists went to the area to search for surface rupture and to canvass damage in the communities around Lake Almanor. While the causative fault had not been identified at the time of the field survey, surface rupture was expected to have occurred just south of Lake Almanor, approximately 2–4 kilometers south of the epicenter. No surface rupture was discovered. Felt intensity among the communities around Lake Almanor appeared to vary significantly. Lake Almanor West (LAW), Lake Almanor Country Club (LACC), and Hamilton Branch (HB) experienced Modified Mercalli Intensity (MMI) ≥7, whereas other communities around the lake experienced MMI ≤6; the maximum observed intensity was MMI 8, in LAW. Damage in the high intensity areas consisted of broken and collapsed chimneys, ruptured pipes, and some damage to foundations and to structural elements within houses. Although this shaking damage is not usually expected for an Mw 5.7 earthquake, the intensities at Lake Almanor Country Club correlate with the peak ground acceleration (38 percent g) and peak ground velocity (30 centimeters per second) recorded by the California Strong Motion Instrumentation Program accelerometer located at the nearby Lake Almanor Fire Station. The intensity distribution for the three hardest hit areas (LAW, LACC, and HB) appears to increase as the azimuth from epicenter to the intensity sites approaches the fault strike. The small communities of Almanor and Prattville on the southwestern shore of Lake Almanor experienced somewhat lower intensities. The town of Canyondam experienced a lower intensity as well, despite its location up-dip of the earthquake rupture. This report contains information on the earthquake itself, the search for surface rupture, and the damage we observed and compiled from other sources. 

The Collapse of Ancient Societies by Great Earthquakes

NASA Astrophysics Data System (ADS)

Nur, A. M.

2001-12-01

Although earthquakes have often been associated with inexplicable past societal disasters their impact has thought to be only secondary for two reasons: Inconclusive archaeological interpretation of excavated destruction, and misconceptions about patterns of seismicity. However, new and revised archaeological evidence and a better understanding of the irregularities of the time-space patterns of large earthquakes together suggest that earthquakes (and associated tsunamis) have probably been responsible for some of the great and enigmatic catastrophes in ancient times. The most relevant aspect of seismicity is the episodic time-space clustering of earthquakes such as during the eastern Mediterranean seismic crisis in the second half of the 4th century AD and the seismicity of the north Anatolian fault during our century. During these earthquake clusters, plate boundary rupture by a series of large earthquakes that occur over a period of only 50 to 100 years or so, followed by hundreds or even thousands of years of relative inactivity. The extent of the destruction by such rare but powerful earthquake clusters must have been far greater than similar modern events due to poorer construction and the lack of any earthquake preparedness in ancient times. The destruction by very big earthquakes also made ancient societies so vulnerable because so much of the wealth and power was concentrated and protected by so few. Thus the breaching by an earthquake of the elite's fortified cities must have often led to attacks by (1) external enemies during ongoing wars (e.g., Joshua and Jericho, Arab attack on Herod's Jerusalem in 31 BCE); (2) neighbors during ongoing conflicts (e.g., Mycenea's fall in @1200 BCE, Saul's battle at Michmash @1020 BCE); and (3) uprisings of poor and often enslaved indigenous populations (e.g., Sparta and the Helots @465 BCE, Hattusas @1200 BCE?, Teotihuacan @ 700 AD). When the devastation was by a local earthquake, during a modest conflict, damage was probably limited and may have required a few tens of years to rebuild. But when severe ground shaking is widespread, and when it happened during a major military conflict the devastation may have been so great that it took hundreds of years for a society to recover- going through a dark ages period during which many of the technical skills (e.g., writing) are abandoned (e.g., the cessation of linear B), construction and repairs of monumental buildings ceased, and looting of building materials by surviving squatters was common. In contrast we can imagine the pastoral countryside, especially away from the tsunami prone coastal areas, to have been much less affected (and perhaps even flourished a little as their tax burden to the ruling elite is reduced). During a regional seismic crisis an entire region must have been subjected to a series of devastations by earthquakes over a short period of time. The catastrophic collapse of the main eastern Mediterranean civilizations at the end of the Bronze Age may be a case in point, with the `Sea People' being mostly squatters and refugees.

Microzonation of seismic risk in a low-rise Latin American city based on the macroseismic evaluation of the vulnerability of residential buildings: Colima city, México

NASA Astrophysics Data System (ADS)

Zobin, V. M.; Cruz-Bravo, A. A.; Ventura-Ramírez, F.

2010-06-01

A macroseismic methodology of seismic risk microzonation in a low-rise city based on the vulnerability of residential buildings is proposed and applied to Colima city, Mexico. The seismic risk microzonation for Colima consists of two elements: the mapping of residential blocks according to their vulnerability level and the calculation of an expert-opinion based damage probability matrix (DPM) for a given level of earthquake intensity and a given type of residential block. A specified exposure time to the seismic risk for this zonation is equal to the interval between two destructive earthquakes. The damage probability matrices were calculated for three types of urban buildings and five types of residential blocks in Colima. It was shown that only 9% of 1409 residential blocks are able to resist to the Modify Mercalli (MM) intensity VII and VIII earthquakes without significant damage. The proposed DPM-2007 is in good accordance with the experimental damage curves based on the macroseismic evaluation of 3332 residential buildings in Colima that was carried out after the 21 January 2003 intensity MM VII earthquake. This methodology and the calculated PDM-2007 curves may be applied also to seismic risk microzonation for many low-rise cities in Latin America, Asia, and Africa.

A physical model of the Mexico City seismic response after the damaging M7.1 earthquake of September 19, 2017

NASA Astrophysics Data System (ADS)

Cruz-Atienza, V. M.; Tago, J.; Villafuerte, C. D.; Chaljub, E.; Sanabria-Gómez, J. D.

2017-12-01

Built-up on top of ancient lake deposits, Mexico City experiences some of the largest seismic site effects in the world. The M7.1 intermediate-depth earthquake of September 19, 2017 (S19) collapsed 43 one-to-ten story buildings in the city close to the western edge of the lake-bed sediments, on top of the geotechnically-known transition zone. In this work we explore the physical reasons explaining such a damaging pattern and the long-lasting strong motion records well-documented from past events by means of new observations and high performance computational modeling. Besides the extreme amplification of seismic waves, duration of intense ground motion in the lake-bed lasts more than three times those recorded in hard-rock a few kilometers away. Different mechanisms contribute to the long lasting motions, such as the regional dispersion and multiple-scattering of the incoming wavefield all the way from the source. However, recent beamforming observations at hard-rock suggest that duration of the incoming field is significantly shorter than the strong shaking in the lake-bed. We show that despite the highly dissipative shallow deposits, seismic energy can propagate long distances in the deep structure of the valley, promoting also a large elongation of motion. Our simulations reveal that the seismic response of the basin is dominated by surface-waves overtones, and that this mechanism increases the duration of ground motion up to 280% and 500% of the incoming wavefield duration at 0.5 and 0.3 Hz, respectively. Furthermore, our results indicate that the damage pattern of the S19 earthquake is most likely due to the propagation of the fundamental mode in the transition zone of the basin. These conclusions contradicts what has been previously stated from observational and modeling investigations, where the basin itself has been discarded as a preponderant factor promoting long and devastating shaking in Mexico City. Reference: Cruz-Atienza, V. M., J. Tago, J. D. Sanabria-Gómez, E. Chaljub, V. Etienne, J. Virieux and L. Quintanar. Long Duration of Ground Motion in the Paradigmatic Valley of Mexico. Nature - Scientific Reports, 6, 38807; doi:10.1038/srep38807, 2016.

Earthquakes; July-August 1982

USGS Publications Warehouse

Person, W.J.

1983-01-01

During this reporting period, there were three major (7.0-7.9) earthquakes all in unpopulated areas. The quakes occurred north of Macquarie Island on July 7, in the Santa Cruz Islands on August 5, and south of Panama on August 19. In the United Stats, a number of earthquakes occurred, but no damage was reported. 

Earthquake Preparedness: What Every Childcare Provider Should Know.

ERIC Educational Resources Information Center

California State Office of Emergency Services, Sacramento.

This brochure provides information to help child care providers reduce or avoid damage, injuries, or loss of life during earthquakes. It first discusses steps to implement before an earthquake strikes, including securing household contents, and practicing with children how to duck and cover. Next, the brochure describes what to do during an…

Shake, Rattle, and Hopefully Not Fall

ERIC Educational Resources Information Center

Maltese, Adam

2009-01-01

Earthquakes occur across the globe, and their efforts can be felt by people regardless of location. However, a moderate earthquake in Pakistan or Turkey may cause much greater damage than a stronger earthquake in Tokyo. It is imperative to help students understand why this disparity exists--often due to both natural and human influences. Students…

The influence of construction measurement and structure storey on seismic performance of masonry structure

NASA Astrophysics Data System (ADS)

Sun, Baitao; Zhao, Hexian; Yan, Peilei

2017-08-01

The damage of masonry structures in earthquakes is generally more severe than other structures. Through the analysis of two typical earthquake damage buildings in the Wenchuan earthquake in Xuankou middle school, we found that the number of storeys and the construction measures had great influence on the seismic performance of masonry structures. This paper takes a teachers’ dormitory in Xuankou middle school as an example, selected the structure arrangement and storey number as two independent variables to design working conditions. Finally we researched on the seismic performance difference of masonry structure under two variables by finite element analysis method.

Triggered earthquakes and the 1811-1812 New Madrid, central United States, earthquake sequence

USGS Publications Warehouse

Hough, S.E.

2001-01-01

The 1811-1812 New Madrid, central United States, earthquake sequence included at least three events with magnitudes estimated at well above M 7.0. I discuss evidence that the sequence also produced at least three substantial triggered events well outside the New Madrid Seismic Zone, most likely in the vicinity of Cincinnati, Ohio. The largest of these events is estimated to have a magnitude in the low to mid M 5 range. Events of this size are large enough to cause damage, especially in regions with low levels of preparedness. Remotely triggered earthquakes have been observed in tectonically active regions in recent years, but not previously in stable continental regions. The results of this study suggest, however, that potentially damaging triggered earthquakes may be common following large mainshocks in stable continental regions. Thus, in areas of low seismic activity such as central/ eastern North America, the hazard associated with localized source zones might be more far reaching than previously recognized. The results also provide additional evidence that intraplate crust is critically stressed, such that small stress changes are especially effective at triggering earthquakes.

The psychological impact of a dual-disaster caused by earthquakes and radioactive contamination in Ichinoseki after the Great East Japan Earthquake.

PubMed

Niitsu, Tomihisa; Takaoka, Kota; Uemura, Saho; Kono, Akiko; Saito, Akihiko; Kawakami, Norito; Nakazato, Michiko; Shimizu, Eiji

2014-05-20

The psychological impact of dual-disasters (earthquakes and a nuclear accident), on affected communities is unknown. This study investigated the impact of a dual-disaster (earthquakes and radioactive contamination) on the prevalence of psychological distress in a landlocked city within the Tohoku area, Japan. A cross-sectional mail-in survey with a random sample of inhabitants from Ichinoseki city was conducted eleven months after the disasters, and data from 902 respondents were analyzed by logistic regression models, with multiple imputation methodology. The K6 was used to determine psychological distress. The estimated prevalence of psychological distress was 48.0 percent. House damage due to earthquakes and anxiety about radioactive contamination were significantly associated with psychological distress (p < 0.05), while an interactive effect between house damage and anxiety about radioactive contamination was not significant. Being female, middle-to-low educational status and unemployed were additional risk factors for psychological distress. This dual-disaster was associated with a moderate prevalence of psychological distress in the area. The impact of the earthquake and radioactive contamination appeared additive.

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.

Impact of the 11 March, 2011, Tohoku earthquake and tsunami on the chemical industry

NASA Astrophysics Data System (ADS)

Krausmann, E.; Cruz, A. M.

2012-04-01

An earthquake of magnitude 9.0 occurred off the Pacific coast of Tohoku, Japan, on March 11, 2011, at 14:46:23 Japan Standard Time (5:46:23 UTC). It generated a tsunami 130 km off the coast of Miyagi Prefecture in northeast Japan, which inundated over 400 km2 of land. The death toll has reached >15,800 according to the Japan National Policy Agency with over 3,700 still missing as of 26 October 2011. Significant damage to or complete collapse of houses also resulted. The earthquake generated strong ground motion; nevertheless most damage was caused by the tsunami, which is a tribute to the effectiveness of Japan's earthquake damage reduction measures in saving lives and property. Nonetheless, the direct losses amount to more than 200 billion US dollars (not counting the costs of the accident at the Fukushima nuclear power plant). The earthquake and tsunami had a significant impact on all types of industry, and in particular on the petrochemical and chemical industry in the affected areas, resulting in hazardous-materials releases, fires and explosions and forcing businesses to interrupt production. These so-called Natech accidents pose an immediate or even long-term threat to the population and the environment, and can also interrupt the supply chain. Overall, the earthquake and tsunami took over 30% of Japan's oil production offline, and two refineries are still not or only partially in operation to repair the damage caused by the fires and explosions. The fire-fighting efforts could only be started 4 days after the disaster due to the absence of personnel that had been evacuated and because of the continuing tsunami alerts. In one of the affected refineries the fires could only be extinguished 10 days after the disasters. Many petrochemical and chemical companies reported problems either due to damage to facilities or because of power outages. In fact, in facilities that suffered no or only minor damage the resuming of operations was hampered by continuous aftershocks, tsunami alerts, the evacuation of personnel, a lack of utilities (water, electricity), damage to infrastructures (berths, roads etc.) and the shortage of raw materials. The Tohoku disaster showed that even prepared countries are at risk and consequently many lessons can be learned for future Natech prevention and mitigation. An in-depth analysis is required to single out the main reasons for the widespread industrial damage and downtime. This analysis, based on information from companies and authorities, in addition to a field visit to the affected areas, is presented.

Uncovering the 2010 Haiti earthquake death toll

NASA Astrophysics Data System (ADS)

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

2013-05-01

Casualties are estimated for the 12 January 2010 earthquake in Haiti using various reports calibrated by observed building damage states from satellite imagery and reconnaissance reports on the ground. By investigating various damage reports, casualty estimates and burial figures, for a one year period from 12 January 2010 until 12 January 2011, there is also strong evidence that the official government figures of 316 000 total dead and missing, reported to have been caused by the earthquake, are significantly overestimated. The authors have examined damage and casualties report to arrive at their estimation that the median death toll is less than half of this value (±137 000). The authors show through a study of historical earthquake death tolls, that overestimates of earthquake death tolls occur in many cases, and is not unique to Haiti. As death toll is one of the key elements for determining the amount of aid and reconstruction funds that will be mobilized, scientific means to estimate death tolls should be applied. Studies of international aid in recent natural disasters reveal that large distributions of aid which do not match the respective needs may cause oversupply of help, aggravate corruption and social disruption rather than reduce them, and lead to distrust within the donor community.

Observations of changes in waveform character induced by the 1999 Mw7.6 Chi-Chi earthquake

USGS Publications Warehouse

Chen, K.H.; Furumura, T.; Rubinstein, J.; Rau, R.-J.

2011-01-01

We observe changes in the waveforms of repeating earthquakes in eastern Taiwan following the 1999 Mw7.6 Chi-Chi earthquake, while their recurrence intervals appear to be unaffected. There is a clear reduction in waveform similarity and velocity changes indicated by delayed phases at the time of the Chi-Chi event. These changes are limited to stations in and paths that cross the 70 × 100 km region surrounding the Chi-Chi source area, the area where seismic intensity and co-seismic surface displacements were largest. This suggests that damage at the near-surface is responsible for the observed waveform changes. Delays are largest in the late S-wave coda, reaching approximately 120 ms. This corresponds to a path averaged Swave velocity reduction of approximately 1%. There is also evidence that damage in the fault-zone caused changes in waveform character at sites in the footwall, where source-receiver paths propagate either along or across the rupture. The reduction in waveform similarity persists through the most recent repeating event in our study (November 15, 2007), indicating that the subsurface damage induced by the Chi-Chi earthquake did not fully heal within the first 8 years following the Chi-Chi earthquake.

Observations of changes in waveform character induced by the 1999 M w7.6 Chi-Chi earthquake

USGS Publications Warehouse

Chen, K.H.; Furumura, T.; Rubinstein, J.; Rau, R.-J.

2011-01-01

We observe changes in the waveforms of repeating earthquakes in eastern Taiwan following the 1999 Mw7.6 Chi-Chi earthquake, while their recurrence intervals appear to be unaffected. There is a clear reduction in waveform similarity and velocity changes indicated by delayed phases at the time of the Chi-Chi event. These changes are limited to stations in and paths that cross the 70 ?? 100 km region surrounding the Chi-Chi source area, the area where seismic intensity and co-seismic surface displacements were largest. This suggests that damage at the near-surface is responsible for the observed waveform changes. Delays are largest in the late S-wave coda, reaching approximately 120 ms. This corresponds to a path averaged S wave velocity reduction of approximately 1%. There is also evidence that damage in the fault-zone caused changes in waveform character at sites in the footwall, where source-receiver paths propagate either along or across the rupture. The reduction in waveform similarity persists through the most recent repeating event in our study (November 15, 2007), indicating that the subsurface damage induced by the Chi-Chi earthquake did not fully heal within the first 8 years following the Chi-Chi earthquake. ?? 2011 by the American Geophysical Union.

Reproductive and Birth Outcomes in Haiti Before and After the 2010 Earthquake.

PubMed

Harville, Emily W; Do, Mai

2016-02-01

We aimed to examine the relationship between exposure to the 2010 Haiti earthquake and pregnancy wantedness, interpregnancy interval, and birth weight. From the nationally representative Haiti 2012 Demographic and Health Survey, information on "size of child at birth" (too small or not) was available for 7280 singleton births in the previous 5 years, whereas information on birth weight was available for 1607 births. Pregnancy wantedness, short (<1 year) interpregnancy interval, and maternal-reported birth weight were compared before and after the earthquake and by level of damage. Multiple logistic regression and linear regression analyses were conducted. Post-earthquake births were less likely to be wanted and more likely to be born after a short interpregnancy interval. Earthquake exposure was associated with increased likelihood of a child being born too small: timing of birth (after earthquake vs. before earthquake, adjusted odds ratio [aOR]: 1.27, 95% confidence interval [CI]: 1.12-1.45), region (hardest-hit vs. rest of country; aOR: 1.43, 95% CI: 1.14- 1.80), and house damage (aOR: 1.27 95% CI: 1.02-1.58). Mean birth weight was 150 to 300 g lower in those exposed to the earthquake. Experience with the earthquake was associated with worse reproductive and birth outcomes, which underscores the need to provide reproductive health services as part of relief efforts.

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 mitigation will be presented. The session includes contributions showing methodological and modelling approaches from scientists in geophysical/seismological, hydrological, remote sensing, civil engineering, insurance, and urbanism, amongst other fields, as well as presentations from practitioners working on specific case studies, regarding analysis of recent events and their impact on cities as well as re-evaluation of past events from the point of view of long-time recovery. In 2005 it was called for: Most strategies for both preparedness and emergency management in case of disaster mitigation are related to urban planning. While natural, engineering and social sciences contribute to the evaluation of the impact of earthquakes and their secondary events (including tsunamis, earthquake triggered landslides, or fire), floods, landslides, high winds, and volcanic eruptions on urban areas, there are the instruments of urban planning which are to be employed for both visualisation as well as development and implementation of strategy concepts for pre- and postdisaster intervention. The evolution of natural systems towards extreme conditions is taken into consideration so far at it concerns the damaging impact on urban areas and infrastructure and the impact on the natural environment of interventions to reduce such damaging impact.

Stochastic strong motion generation using slip model of 21 and 22 May 1960 mega-thrust earthquakes in the main cities of Central-South Chile

NASA Astrophysics Data System (ADS)

Ruiz, S.; Ojeda, J.; DelCampo, F., Sr.; Pasten, C., Sr.; Otarola, C., Sr.; Silva, R., Sr.

2017-12-01

In May 1960 took place the most unusual seismic sequence registered instrumentally. The Mw 8.1, Concepción earthquake occurred May, 21, 1960. The aftershocks of this event apparently migrated to the south-east, and the Mw 9.5, Valdivia mega-earthquake occurred after 33 hours. The structural damage produced by both events is not larger than other earthquakes in Chile and lower than crustal earthquakes of smaller magnitude. The damage was located in the sites with shallow soil layers of low shear wave velocity (Vs). However, no seismological station recorded this sequence. For that reason, we generate synthetic acceleration times histories for strong motion in the main cities affected by these events. We use 155 points of vertical surface displacements recopiled by Plafker and Savage in 1968, and considering the observations of this authors and local residents we separated the uplift and subsidence information associated to the first earthquake Mw 8.1 and the second mega-earthquake Mw 9.5. We consider the elastic deformation propagation, assume realist lithosphere geometry, and compute a Bayesian method that maximizes the probability density a posteriori to obtain the slip distribution. Subsequently, we use a stochastic method of generation of strong motion considering the finite fault model obtained for both earthquakes. We considered the incidence angle of ray to the surface, free surface effect and energy partition for P, SV and SH waves, dynamic corner frequency and the influence of site effect. The results show that the earthquake Mw 8.1 occurred down-dip the slab, the strong motion records are similar to other Chilean earthquake like Tocopilla Mw 7.7 (2007). For the Mw 9.5 earthquake we obtain synthetic acceleration time histories with PGA values around 0.8 g in cities near to the maximum asperity or that have low velocity soil layers. This allows us to conclude that strong motion records have important influence of the shallow soil deposits. These records correlate well with our structural damage observations.

Damage in the town of Miahuatlan by Oaxaca earthquake of September 30, 1999

NASA Astrophysics Data System (ADS)

Cuenca, J.; Bernal, I.

2007-05-01

Instituto de Ingeniería Coordinación de Ingeniería Sismológica Universidad Nacional Autónoma de México jccsa@pumas.ingen.unam.mx On September 30, 1999 (11:31 local time) a 7.4-magnitude earthquake occurred along the coast of the southern state of Oaxaca (by its proximity called Puerto Escondido earthquake) resulting of subduction of the Cocos plate under the North American continental plate. Reported fatalities 30 people and much more injured. The intense movement felt by people in Mexico City with great scare, caused considerable damage in churches of Oaxaca, as religious representative monuments. Its behavior was some stronger and better earthquake resistant characteristics. Very much houses made of adobe widely used in a poorest state were damaged. Many heavy parapets fell over the street. From 440 km to Mexico City (with light damage) was registered maximum horizontal acceleration of 28 cm/s2, also near to 137 km from the epicenter with 196 cm/s2 on Oaxaca City, were the damage was concentrated, with more than 260 historical building. Constructions moderns were not damaged. To south of Oaxaca the rural town of Miahuatlan was damaged in your adobe houses and some of them destroyed with wood roofs supporting clay tiles, your principal church suffer the collapse of the tower in the side left and some failures in the interior of this church. The fallen superior part of its left tower was projected toward the left side and the other tower of right side not collapsed. Crack in the walls bordering the base of the towers (over the ceiling) as a form of stresses acting along to small walls with cracks in X form (showing effects in this walls to the action of inverted pendulum), as indication of the movement on the four directions. Also was observed some cracks in the small arcs of the towers and in a very high parapet upon of the entrance in the upper in the front of the church without cracks or collapse. It is showed much of the failure in adobe houses characteristic from damage for earthquake. Others adobe houses reinforce in your base not suffered damage due to this and wide walls.

Effectiveness of modified pushover analysis procedure for the estimation of seismic demands of buildings subjected to near-fault ground motions having fling step

NASA Astrophysics Data System (ADS)

Mortezaei, A.; Ronagh, H. R.

2013-06-01

Near-fault ground motions with long-period pulses have been identified as being critical in the design of structures. These motions, which have caused severe damage in recent disastrous earthquakes, are characterized by a short-duration impulsive motion that transmits large amounts of energy into the structures at the beginning of the earthquake. In nearly all of the past near-fault earthquakes, significant higher mode contributions have been evident in building structures near the fault rupture, resulting in the migration of dynamic demands (i.e. drifts) from the lower to the upper stories. Due to this, the static nonlinear pushover analysis (which utilizes a load pattern proportional to the shape of the fundamental mode of vibration) may not produce accurate results when used in the analysis of structures subjected to near-fault ground motions. The objective of this paper is to improve the accuracy of the pushover method in these situations by introducing a new load pattern into the common pushover procedure. Several pushover analyses are performed for six existing reinforced concrete buildings that possess a variety of natural periods. Then, a comparison is made between the pushover analyses' results (with four new load patterns) and those of FEMA (Federal Emergency Management Agency)-356 with reference to nonlinear dynamic time-history analyses. The comparison shows that, generally, the proposed pushover method yields better results than all FEMA-356 pushover analysis procedures for all investigated response quantities and is a closer match to the nonlinear time-history responses. In general, the method is able to reproduce the essential response features providing a reasonable measure of the likely contribution of higher modes in all phases of the response.

The Near-Source Intensity Distribution for the August 24, 2014, South Napa Earthquake

NASA Astrophysics Data System (ADS)

Boatwright, J.; Pickering, A.; Blair, J. L.

2016-12-01

The 2014 Mw=6.0 South Napa earthquake was the largest and most damaging earthquake to occur in the Bay Area since the 1989 Mw=6.9 Loma Prieta earthquake. The City of Napa estimated that the earthquake caused 300 million damage to homes and commercial properties and 58 million to public infrastructure. Over 41,000 reports were entered on the USGS "Did You Feel It?" (DYFI) website: 730 of these reports were located within 15 km of the rupture. Unfortunately, very few geocoded intensities were obtained immediately west and north of the rupture area. In the weeks following the earthquake, we conducted an intensity survey focused on areas poorly sampled by the DYFI reports. 75 sites were surveyed within 15 km of the earthquake rupture. In addition, we checked and manually geocoded many of the DYFI reports, locating 245 reports within 15 km of the rupture that the automated DYFI processing failed to geocode. We combine the survey sites and the newly geocoded DYFI reports with the original geocoded DYFI reports to map and contour the near-source shaking intensity. In addition to imaging the strong shaking (MMI 7.0-8.0) in the City of Napa, we find an area of very strong shaking (MMI 7.5-8.0) to the northwest of the earthquake rupture. This area, marked by ground cracks, damage to modern wood-frame buildings, and reports of people knocked down, coincides with the directivity expected for rupture to the northwest and up dip. The intensities from the survey sites are consistent with the intensities from the DYFI reports, but are much less variable. For DYFI intensities MMI 4-6, this variability could be derived from the 3:20 AM occurrence of the earthquake: some of the effects that the DYFI questionnaire uses to assign these intensities (objects swaying, bushes and trees shaken) cannot be observed in the dark.

Social tension as precursor of large damaging earthquake: legend or reality?

NASA Astrophysics Data System (ADS)

Molchanov, O.

2008-11-01

Using case study of earthquake (EQ) activity and war conflicts in Caucasus during 1975 2002 time interval and correlation analysis of global distribution of damaging EQs and war-related social tension during 1901 2005 period we conclude:

• There is a statistically reliable increase of social tension several years (or several months in case study) before damaging EQs,
• There is evident decrease of social tension several years after damaging EQs, probably due to society consolidation,
• Preseismic effect is absent for the large EQs in unpopulated areas,
• There is some factual background for legendary belief in Almighty retribution for social abnormal behavior.

Lessons learned from the 12 May 2008 Wenchuan earthquake: Impact on industry

NASA Astrophysics Data System (ADS)

Krausmann, E.; Cruz, A. M.; Affeltranger, B.

2009-04-01

The earthquake that shook Wenchuan County in China's Sichuan Province on 12 May 2008 was a major event with a moment magnitude of MW = 7.9 and a depth of only 19 km. It caused a fault rupture of 270 km length and affected a total area of about 500,000 km2. With the intensity reaching XI in the region near the epicentre and peak ground acceleration values as high as 0.63g the earthquake killed almost 70,000 people, injured over 374,000 and rendered 5,000,000 homeless. Over 18,000 are still listed as missing. Prior to the earthquake the area was considered a region of moderate seismicity with a design intensity of 7. Sichuan Province is home to a significant proportion of Chinese chemical and nuclear industry and consequently has a very strong economy. The direct economic loss due to the earthquake amounts to over 1.1 billion Euros. In addition to economic damage there is also concern about earthquake-triggered damage to and destruction of industrial facilities housing or processing hazardous substances and the potential consequences of their release to man or the environment. In order to understand how well the chemical industry fared in the earthquake-affected areas a reconnaissance field trip was organised from 15-21 November, 2008, which included visits to industry in Deyang, Shifang, Mianzhu, Mianyang, Anxian and Dujiangyan. In total we collected information on earthquake effects at 18 industrial facilities. Lessons learned from this reconnaissance field trip confirm the devastating consequences that natural disasters can have on industrial facilities. In addition to casualties and environmental harm the economic losses due to damage, prolonged shut-down periods and business interruption are often ruinous and may result in lay-off of workers. In the case of the visited facilities the shut-down time was up to 6 months. Two facilities were damaged beyond repair and have resulted in significant ammonia, sulphuric acid and other releases that in addition to polluting a river also necessitated the evacuation of 6,000 residents. The main cause of worker death and injury was the collapse of warehouses, office and manufacturing buildings. This concerned mostly concrete structures with insufficient confinement or poor reinforcement that could not withstand the earthquake loads. The falling debris resulted in equipment damage and loss, as well as pipe severing and crushing in buildings housing machinery. This was brought about either by direct debris impact or by support failure inside buildings. Pipes were also severed, bent or crushed outside of structures when connected tanks were displaced or buildings collapsed, although in many cases anchoring proved to be effective in avoiding displacement. Pipe support concrete columns in the open generally performed well. In some sites soil-liquefaction induced damage was evident, highlighting the need to consider potential site effects when selecting the location for a facility.

Seismic design and engineering research at the U.S. Geological Survey

USGS Publications Warehouse

1988-01-01

The Engineering Seismology Element of the USGS Earthquake Hazards Reduction Program is responsible for the coordination and operation of the National Strong Motion Network to collect, process, and disseminate earthquake strong-motion data; and, the development of improved methodologies to estimate and predict earthquake ground motion.  Instrumental observations of strong ground shaking induced by damaging earthquakes and the corresponding response of man-made structures provide the basis for estimating the severity of shaking from future earthquakes, for earthquake-resistant design, and for understanding the physics of seismologic failure in the Earth's crust.

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

Recovering from the ShakeOut earthquake

USGS Publications Warehouse

Wein, Anne; Johnson, Laurie; Bernknopf, Richard

2011-01-01

Recovery from an earthquake like the M7.8 ShakeOut Scenario will be a major endeavor taking many years to complete. Hundreds of Southern California municipalities will be affected; most lack recovery plans or previous disaster experience. To support recovery planning this paper 1) extends the regional ShakeOut Scenario analysis into the recovery period using a recovery model, 2) localizes analyses to identify longer-term impacts and issues in two communities, and 3) considers the regional context of local recovery.Key community insights about preparing for post-disaster recovery include the need to: geographically diversify city procurement; set earthquake mitigation priorities for critical infrastructure (e.g., airport), plan to replace mobile homes with earthquake safety measures, consider post-earthquake redevelopment opportunities ahead of time, and develop post-disaster recovery management and governance structures. This work also showed that communities with minor damages are still sensitive to regional infrastructure damages and their potential long-term impacts on community recovery. This highlights the importance of community and infrastructure resilience strategies as well.

Tsunami hazards to U.S. coasts from giant earthquakes in Alaska

USGS Publications Warehouse

Ryan, Holly F.; von Huene, Roland E.; Scholl, Dave; Kirby, Stephen

2012-01-01

In the aftermath of Japan's devastating 11 March 2011Mw 9.0 Tohoku earthquake and tsunami, scientists are considering whether and how a similar tsunami could be generated along the Alaskan-Aleutian subduction zone (AASZ). A tsunami triggered by an earthquake along the AASZ would cross the Pacific Ocean and cause extensive damage along highly populated U.S. coasts, with ports being particularly vulnerable. For example, a tsunami in 1946 generated by a Mw 8.6 earthquake near Unimak Pass, Alaska (Figure 1a), caused significant damage along the U.S. West Coast, took 150 lives in Hawaii, and inundated shorelines of South Pacific islands and Antarctica [Fryer et al., 2004; Lopez and Okal, 2006]. The 1946 tsunami occurred before modern broadband seismometers were in place, and the mechanisms that created it remain poorly understood.

Use of Ground Motion Simulations of a Historical Earthquake for the Assessment of Past and Future Urban Risks

NASA Astrophysics Data System (ADS)

Kentel, E.; Çelik, A.; karimzadeh Naghshineh, S.; Askan, A.

2017-12-01

Erzincan city located in the Eastern part of Turkey at the conjunction of three active faults is one of the most hazardous regions in the world. In addition to several historical events, this city has experienced one of the largest earthquakes during the last century: The 27 December 1939 (Ms=8.0) event. With limited knowledge of the tectonic structure by then, the city center was relocated to the North after the 1939 earthquake by almost 5km, indeed closer to the existing major strike slip fault. This decision coupled with poor construction technologies, led to severe damage during a later event that occurred on 13 March 1992 (Mw=6.6). The 1939 earthquake occurred in the pre-instrumental era in the region with no available local seismograms whereas the 1992 event was only recorded by 3 nearby stations. There are empirical isoseismal maps from both events indicating indirectly the spatial distribution of the damage. In this study, we focus on this region and present a multidisciplinary approach to discuss the different components of uncertainties involved in the assessment and mitigation of seismic risk in urban areas. For this initial attempt, ground motion simulation of the 1939 event is performed to obtain the anticipated ground motions and shaking intensities. Using these quantified results along with the spatial distribution of the observed damage, the relocation decision is assessed and suggestions are provided for future large earthquakes to minimize potential earthquake risks.

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 scenarios was guided by the perception that usable and realistic (also in the sense of being compatible with seismic histories of cities that are several centuries long) ground motion maps had to be produced for urban areas. By deterministic scenario it is mean a representation of the severity of ground shaking over an urban area, using one or more hazard descriptors. Such representation can be obtained: - either from the assumption of a "reference earthquake" specified by a magnitude or an epicentral intensity, associated to a particular earthquake source - or, directly, showing values of local macroseimic intensity generated by a damaging, real earthquakes of the past. In the study we chose for the second method using the values of macroseimic intensity caused by damaging historical earthquakes (the 1928 quakes in southern Bulgaria; the 1940 and the 1977 Vrancea intermediate earthquakes) - lessons from the past. Such scenarios are intended as a basic input for developing detailed earthquake damage scenarios for the cities and can be used in earthquake-safe town and infrastructure planning.

Urban Earthquake Shaking and Loss Assessment

NASA Astrophysics Data System (ADS)

Hancilar, U.; Tuzun, C.; Yenidogan, C.; Zulfikar, C.; Durukal, E.; Erdik, M.

2009-04-01

This study, conducted under the JRA-3 component of the EU NERIES Project, develops a methodology and software (ELER) for the rapid estimation of earthquake shaking and losses the Euro-Mediterranean region. This multi-level methodology developed together with researchers from Imperial College, NORSAR and ETH-Zurich is capable of incorporating regional variability and sources of uncertainty stemming from ground motion predictions, fault finiteness, site modifications, inventory of physical and social elements subjected to earthquake hazard and the associated vulnerability relationships. GRM Risk Management, Inc. of Istanbul serves as sub-contractor tor the coding of the ELER software. The methodology encompasses the following general steps: 1. Finding of the most likely location of the source of the earthquake using regional seismotectonic data base and basic source parameters, and if and when possible, by the estimation of fault rupture parameters from rapid inversion of data from on-line stations. 2. Estimation of the spatial distribution of selected ground motion parameters through region specific ground motion attenuation relationships and using shear wave velocity distributions.(Shake Mapping) 4. Incorporation of strong ground motion and other empirical macroseismic data for the improvement of Shake Map 5. Estimation of the losses (damage, casualty and economic) at different levels of sophistication (0, 1 and 2) that commensurate with the availability of inventory of human built environment (Loss Mapping) Level 2 analysis of the ELER Software (similar to HAZUS and SELENA) is essentially intended for earthquake risk assessment (building damage, consequential human casualties and macro economic loss quantifiers) in urban areas. The basic Shake Mapping is similar to the Level 0 and Level 1 analysis however, options are available for more sophisticated treatment of site response through externally entered data and improvement of the shake map through incorporation of accelerometric and other macroseismic data (similar to the USGS ShakeMap System). The building inventory data for the Level 2 analysis will consist of grid (geo-cell) based urban building and demographic inventories. For building grouping the European building typology developed within the EU-FP5 RISK-EU project is used. The building vulnerability/fragility relationships to be used can be user selected from a list of applicable relationships developed on the basis of a comprehensive study, Both empirical and analytical relationships (based on the Coefficient Method, Equivalent Linearization Method and the Reduction Factor Method of analysis) can be employed. Casualties in Level 2 analysis are estimated based on the number of buildings in different damaged states and the casualty rates for each building type and damage level. Modifications to the casualty rates can be used if necessary. ELER Level 2 analysis will include calculation of direct monetary losses as a result building damage that will allow for repair-cost estimations and specific investigations associated with earthquake insurance applications (PML and AAL estimations). ELER Level 2 analysis loss results obtained for Istanbul for a scenario earthquake using different techniques will be presented with comparisons using different earthquake damage assessment software. The urban earthquake shaking and loss information is intented for dissemination in a timely manner to related agencies for the planning and coordination of the post-earthquake emergency response. However the same software can also be used for scenario earthquake loss estimation, related Monte-Carlo type simulations and eathquake insurance applications.

The hazard map of ML6.6 0206 Meinong earthquake near Guanmiao and its Neotectonic implication

NASA Astrophysics Data System (ADS)

Chung, L. H.; Shyu, J. B. H.; Huang, M. H.; Yang, K. M.; Le Beon, M.; Lee, Y. H.; Chuang, R.; Yi, D.

2016-12-01

The serious damage was occurred in SW Taiwan by ML 6.6 0206 Meinong earthquake. Based on InSAR result, 10 cm oval-raised surface deformation is 15 km away from its epicenter, and two obviously N-S trend sharp phase change nearby Guanmiao area. Our field investigation shows bulling damage and surface fracture are high related with the two sharp phase change. Here, we perform the detailed shallow underground geometry by using reflection seismic data, geologic data, and field hazard investigation. This N-S trend surface deformation may be induced by local shallow folding, while the huge uplift west of Guanmiao may be related with pure shear deformation of thick clayey Gutingkeng (GTK) Formation. Our results imply that not only a moderate lower crustal earthquake can trigger active structure at shallower depth, but also those minor shallow active structures are occurred serious damage and surface deformation.

Estimation of Damaged Areas due to the 2010 Chile Earthquake and Tsunami Using SAR Imagery of Alos/palsar

NASA Astrophysics Data System (ADS)

Made, Pertiwi Jaya Ni; Miura, Fusanori; Besse Rimba, A.

2016-06-01

A large-scale earthquake and tsunami affect thousands of people and cause serious damages worldwide every year. Quick observation of the disaster damage is extremely important for planning effective rescue operations. In the past, acquiring damage information was limited to only field surveys or using aerial photographs. In the last decade, space-borne images were used in many disaster researches, such as tsunami damage detection. In this study, SAR data of ALOS/PALSAR satellite images were used to estimate tsunami damage in the form of inundation areas in Talcahuano, the area near the epicentre of the 2010 Chile earthquake. The image processing consisted of three stages, i.e. pre-processing, analysis processing, and post-processing. It was conducted using multi-temporal images before and after the disaster. In the analysis processing, inundation areas were extracted through the masking processing. It consisted of water masking using a high-resolution optical image of ALOS/AVNIR-2 and elevation masking which built upon the inundation height using DEM image of ASTER-GDEM. The area result was 8.77 Km2. It showed a good result and corresponded to the inundation map of Talcahuano. Future study in another area is needed in order to strengthen the estimation processing method.

Advancing Integrated STEM Learning through Engineering Design: Sixth-Grade Students' Design and Construction of Earthquake Resistant Buildings

ERIC Educational Resources Information Center

English, Lyn D.; King, Donna; Smeed, Joanna

2017-01-01

As part of a 3-year longitudinal study, 136 sixth-grade students completed an engineering-based problem on earthquakes involving integrated STEM learning. Students employed engineering design processes and STEM disciplinary knowledge to plan, sketch, then construct a building designed to withstand earthquake damage, taking into account a number of…

24 CFR 203.379 - Adjustment for damage or neglect.

Code of Federal Regulations, 2012 CFR

2012-04-01

..., or tornado, or, for mortgages insured on or after January 1, 1977, the property has suffered damage..., earthquake, hurricane, or tornado, or if it was damaged notwithstanding reasonable action by the mortgagee as...

24 CFR 203.379 - Adjustment for damage or neglect.

Code of Federal Regulations, 2014 CFR

2014-04-01

..., or tornado, or, for mortgages insured on or after January 1, 1977, the property has suffered damage..., earthquake, hurricane, or tornado, or if it was damaged notwithstanding reasonable action by the mortgagee as...

24 CFR 203.379 - Adjustment for damage or neglect.

Code of Federal Regulations, 2010 CFR

2010-04-01

..., or tornado, or, for mortgages insured on or after January 1, 1977, the property has suffered damage..., earthquake, hurricane, or tornado, or if it was damaged notwithstanding reasonable action by the mortgagee as...

24 CFR 203.379 - Adjustment for damage or neglect.

Code of Federal Regulations, 2011 CFR

2011-04-01

..., or tornado, or, for mortgages insured on or after January 1, 1977, the property has suffered damage..., earthquake, hurricane, or tornado, or if it was damaged notwithstanding reasonable action by the mortgagee as...

24 CFR 203.379 - Adjustment for damage or neglect.

Code of Federal Regulations, 2013 CFR

2013-04-01

..., or tornado, or, for mortgages insured on or after January 1, 1977, the property has suffered damage..., earthquake, hurricane, or tornado, or if it was damaged notwithstanding reasonable action by the mortgagee as...

Field investigation on severely damaged aseismic buildings in 2014 Ludian earthquake

NASA Astrophysics Data System (ADS)

Lin, Xuchuan; Zhang, Haoyu; Chen, Hongfu; Chen, Hao; Lin, Junqi

2015-03-01

The 2014 magnitude 6.5 Ludian earthquake caused a death toll of 617, many landslides and tens of thousands of collapsed buildings. A field investigation to evaluate the damage to buildings was carried out immediately after the occurrence of the earthquake. Severely damaged aseismic buildings, which were basically observed in the downtown of Longtoushan Town, were carefully examined one by one with the aim to improve design codes. This paper summarizes the damage observed to the investigated aseismic buildings in both the structural and local levels. A common failure mode was observed that most of the aseismic buildings, such as RC frame structures and confined masonry structures, were similarly destroyed by severe damage or complete collapse of the first story. The related strong ground motion, which was recorded at the nearby station, had a short duration of less than 20 s but a very large PGA up to 1.0 g. The RC frames based on the new design codes still failed to achieve the design target for "strong column, weak beam". Typical local failure details, which were related to the interaction between RC columns and infill walls and between constructional columns and masonry walls, are summarized with preliminary analyses.

Failure behavior of concrete pile and super-structure dynamic response as a result of soil liquefaction during earthquake

NASA Astrophysics Data System (ADS)

Kaneda, Shogo; Hayashi, Kazuhiro; Hachimori, Wataru; Tamura, Shuji; Saito, Taiki

2017-10-01

In past earthquake disasters, numerous building structure piles were damaged by soil liquefaction occurring during the earthquake. Damage to these piles, because they are underground, is difficult to find. The authors aim to develop a monitoring method of pile damage based on superstructure dynamic response. This paper investigated the relationship between the damage of large cross section cementitious piles and the dynamic response of the super structure using a centrifuge test apparatus. A dynamic specimen used simple cross section pile models consisting of aluminum rod and mortar, a saturated soil (Toyoura sand) of a relative density of 40% and a super structure model of a natural period of 0.63sec. In the shaking table test under a 50G field (length scale of 1/50), excitation was a total of 3 motions scaled from the Rinkai wave at different amplitudes. The maximum acceleration of each of the excitations was 602gal, 336gal and 299gal. The centrifuge test demonstrated the liquefaction of saturated soil and the failure behavior of piles. In the test result, the damage of piles affected the predominant period of acceleration response spectrum on the footing of the superstructure.

The next big earthquake in the Bay Area may come sooner than you think—Are you prepared?

USGS Publications Warehouse

,

1990-01-01

Many of us breathed a little easier after October 17, 1989. The Lorna Prieta earthquake, 7.1 on the Richter scale, meant that the big one, talked about for decades, had finally happened. And, bad as it was, we had survived.There are two things wrong with that. First, Lorna Prieta was not the big one. It was a moderately big one, certainly destructive to some parts of the Bay Area, but nowhere near the size of the great San Francisco earthquake of 1906. Second, having an earthquake like Lorna Prieta has little to do with the likelihood of having another one on a different fault, somewhere else in the area.The inevitability of a damaging earthquake still confronts everybody in the Bay Area, and we still risk substantial damage. A new study, released in July 1990 by the United States Geological Survey, says that there is a 67 percent chance of another earthquake the size of Lorna Prieta during the next 30 years and that the quake could strike at any time, including today. In other words, scientists think that a magnitude 7 or larger earthquake is now twice as likely to happen as not to happen. This is a substantial increase, since in 1988, scientists thought the chance for such an earthquake was 50 percent Gust as likely to occur as not to occur) within 30 years.The new report also says that the next one will most likely strike farther north than Lorna Prieta, somewhere between San Jose and Santa Rosa on either side of the Bay. The epicenter of the October 1989 quake was in a sparsely populated area. The next one, according to the study, will likely be centered in a more populated area. During the Lorna Prieta earthquake, shaking was so severe in the Santa Cruz Mountains that a van overturned, treetops snapped off, and many people were thrown to the ground. Because the next one is expected to strike closer to an urban area, it will cause much more damage.Fortunately, there is something we can do about it. By taking actions, such as those described in this booklet, we can drastically reduce the losses and we can make the Bay Area a safer place to live. Earthquake damage is particularly great in certain locations and in certain buildings. Most locations and most modem buildings are relatively safe. By identifying the greatest hazards, we can set priorities for using our limited resources most effectively to reduce them. The choice is ours.

Method for detecting moment connection fracture using high-frequency transients in recorded accelerations

USGS Publications Warehouse

Rodgers, J.E.; Elebi, M.

2011-01-01

The 1994 Northridge earthquake caused brittle fractures in steel moment frame building connections, despite causing little visible building damage in most cases. Future strong earthquakes are likely to cause similar damage to the many un-retrofitted pre-Northridge buildings in the western US and elsewhere. Without obvious permanent building deformation, costly intrusive inspections are currently the only way to determine if major fracture damage that compromises building safety has occurred. Building instrumentation has the potential to provide engineers and owners with timely information on fracture occurrence. Structural dynamics theory predicts and scale model experiments have demonstrated that sudden, large changes in structure properties caused by moment connection fractures will cause transient dynamic response. A method is proposed for detecting the building-wide level of connection fracture damage, based on observing high-frequency, fracture-induced transient dynamic responses in strong motion accelerograms. High-frequency transients are short (<1 s), sudden-onset waveforms with frequency content above 25 Hz that are visually apparent in recorded accelerations. Strong motion data and damage information from intrusive inspections collected from 24 sparsely instrumented buildings following the 1994 Northridge earthquake are used to evaluate the proposed method. The method's overall success rate for this data set is 67%, but this rate varies significantly with damage level. The method performs reasonably well in detecting significant fracture damage and in identifying cases with no damage, but fails in cases with few fractures. Combining the method with other damage indicators and removing records with excessive noise improves the ability to detect the level of damage. ?? 2010 Elsevier B.V. All rights reserved.

U.S. Geological Survey National Strong-Motion Project strategic plan, 2017–22

USGS Publications Warehouse

Aagaard, Brad T.; Celebi, Mehmet; Gee, Lind; Graves, Robert; Jaiswal, Kishor; Kalkan, Erol; Knudsen, Keith L.; Luco, Nicolas; Smith, James; Steidl, Jamison; Stephens, Christopher D.

2017-12-11

The mission of the National Strong-Motion Project is to provide measurements of how the ground and built environment behave during earthquake shaking to the earthquake engineering community, the scientific community, emergency managers, public agencies, industry, media, and other users for the following purposes: Improving engineering evaluations and design methods for facilities and systems;Providing timely information for earthquake early warning, damage assessment, and emergency response action; andContributing to a greater understanding of the mechanics of earthquake rupture, groundmotion characteristics, and earthquake effects.

Did you feel it? : citizens contribute to earthquake science

USGS Publications Warehouse

Wald, David J.; Dewey, James W.

2005-01-01

Since the early 1990s, the magnitude and location of an earthquake have been available within minutes on the Internet. Now, as a result of work by the U.S. Geological Survey and with the cooperation of various regional seismic networks, people who experience an earthquake can go online and share information about its effects to help create a map of shaking intensities and damage. Such “Community Internet Intensity Maps” (CIIMs) contribute greatly toward the quick assessment of the scope of an earthquake emergency and provide valuable data for earthquake research.

Geological indicators of a suspected seismic source from Peninsular India

NASA Astrophysics Data System (ADS)

Singh, Yogendra; John, Biju; P, Ganapathy G.; S, Divyalakshmi K.

2014-05-01

An increase in seismicity in Peninsular India during the last few decades has initiated various studies for identifying seismogenic structures and their behaviour. Even though few earthquakes occurred at well defined structures many of them occurred at unexpected locations where no previous seismicity reported. However, studies subsequent to the 1993 Latur earthquake as well as the studies at different parts of peninsular India, have led to the identification of pre-existing faults that have activated in the past. Studies elsewhere in the cratonic hinderland also show that the damaging earthquakes occur on pre-existing faults with a recurrence period of tens of thousands of year Studies subsequent to 1989 Wadakkancheri earthquake (M=4.3) identified Desamangalam fault which are capable of generating earthquakes. However, it is noted that a number of later events are occurring much south of the Desamangalam fault. We identified a set of NW-SE trending lineaments which are influencing the drainage pattern of the area. A network of paleochannels is also observed in the remote sensing analysis and field studies in this area. Regionally these lineaments meeting one of the major lineaments in central Kerala called Periyar lineament, in the south. Charnockite rocks constitutes the major rock type of the region. These rocks at places developed strong foliation similar to the lineament direction. Detailed field studies identified oblique movement (reverse and strike slip component) along NW-SE trending faults which are dipping south-west. The studies also find NNE-SSW trending vertical faults showing strike-slip movement. The damage zones of each of these faults bears different mineral precipitations and gouge injections of episodic nature. The presence of loose gouge may indicate the faulting is a much later development in the brittle regime. The sense of movement of the observed faults may indicate that the various river/drainage abandonment observed in the area are due to the movement of these faults. The correlation of the ongoing earthquake activity with these faults and their sense of movement akin to the present stress condition of Peninsular India and its episodic nature as well as its influence on the drainage network of the area may indicate that these faults may be adjusting to the present tectonic regime and are capable of producing moderate events. Key words Peninsular India, stress regime, lineaments, brittle deformation

Field survey of the 1 April 2014 Iquique tsunami along the coasts of Chile and Peru

NASA Astrophysics Data System (ADS)

Lagos, M.; Fritz, H. M.

2014-12-01

On 1 April, 2014 a magnitude Mw 8.2 earthquake occurred off the coast of northern Chile less than 100 km NW of Iquique within a region of historic quiescence termed the northern Chile seismic gap. The ensuing tsunami inundation caused mostly minor damage centered in Iquique and neighbouring stretches of coastline. Fortunately, ancestral knowledge from the past 1868 and 1877 tsunamis in the region along with the recent 2010 Maule tsunami, as well as tsunami education and evacuation exercises prompted most coastal residents to spontaneously evacuate to high ground after the earthquake. There were no tsunami victims, while a handful of fatalities were associated to the earthquake and the tsunami evacuation. The local scientist deployed in the morning hours to start the tsunami survey in Iquique on the day after the earthquake. The international scientist joined the local effort from April 6 to 11. The international tsunami survey team (ITST) documented flow depths, runup heights, inundation distances, sediment deposition, damage patterns, performance of the navigation infrastructure and impact on the natural environment. The ITST covered a 700 km stretch of coastline from the Mejillones Peninsula (23.5° S) north of Antofagasta in Chile up to Vila Vila (18.1° S) in southern Peru. We surveyed 30 locations with differential GPS and laser range finders. The tsunami impact peaked in the vicinity of Iquique exceeding 4 m in tsunami height. A significant variation in tsunami impact was observed along the coastlines of Chile and Peru both at local and regional scales. The tsunami occurred in the evening hours limiting the availability of eyewitness video footages. Observations from the 2014 Chile tsunami are compared against the 1868, 1877 and 2010 Chile tsunamis. Given the magnitude of the 1 April 2014 earthquake the tsunami could have been significantly larger. However the absence of a massive tsunami may mislead residents in the future to believe another minor tsunami may be generated after an earthquake of similar magnitude. Hence the April fool's day event poses significant challenges to community-based education. The team interviewed numerous eyewitnesses and educated residents about tsunami hazards since awareness programs are essential to save lives in locales at risk from locally generated tsunamis.

Earthquakes, September-October, 1979

USGS Publications Warehouse

Person, W.J.

1980-01-01

In the United States, California experienced the strongest earthquake in that State since 1971. The quake, a M=6.8, occurred on October 15, in Baja California, Mexico, near the California border and caused injuries and damage. 

Towards to Resilience Science -Research on the Nankai trough seismogenic zone-

NASA Astrophysics Data System (ADS)

Kaneda, Yoshiyuki; Shiraki, Wataru; Fujisawa, Kazuhito; Tokozakura, Eiji

2017-04-01

For the last few decades, many destructive earthquakes and tsunamis occurred in the world. Based on lessons learnt from 2004 Sumatra Earthquake/Tsunamis, 2010 Chilean Earthquake/Tsunami and 2011 East Japan Earthquake/Tsunami, we recognized the importance of real time monitoring on Earthquakes and Tsunamis for disaster mitigation. Recently, Kumamoto Earthquake occurred in 2006. This destructive Earthquake indicated that multi strong motions including pre shock and main shock generated severe earthquake damages buildings. Furthermore, we recognize recovers/ revivals are very important and difficult. In Tohoku area damaged by large tsunamis, recovers/revivals have been under progressing after over 5 years passed after the 2011 Tohoku Earthquake. Therefore, we have to prepare the pre plan before next destructive disasters such as the Nankai trough mega thrust earthquake. As one of disaster countermeasures, we would like to propose that Disaster Mitigation Science. This disaster mitigation science is including engineering, science, medicine and social science such as sociology, informatics, law, literature, art, psychology etc. For Urgent evacuations, there are some kinds of real time monitoring system such as Dart buoy and ocean floor network. Especially, the real time monitoring system using multi kinds of sensors such as the accelerometer, broadband seismometer, pressure gauge, difference pressure gauge, hydrophone and thermometer is indispensable for Earthquakes/ Tsunamis monitoring. Furthermore, using multi kind of sensors, we can analyze and estimate broadband crustal activities around mega thrust earthquake seismogenic zones. Therefore, we deployed DONET1 and DONET2 which are dense ocean floor networks around the Nankai trough Southwestern Japan. We will explain about Resilience Science and real time monitoring systems around the Nankai trough seismogenic zone.

A Virtual Tour of the 1868 Hayward Earthquake in Google EarthTM

NASA Astrophysics Data System (ADS)

Lackey, H. G.; Blair, J. L.; Boatwright, J.; Brocher, T.

2007-12-01

The 1868 Hayward earthquake has been overshadowed by the subsequent 1906 San Francisco earthquake that destroyed much of San Francisco. Nonetheless, a modern recurrence of the 1868 earthquake would cause widespread damage to the densely populated Bay Area, particularly in the east Bay communities that have grown up virtually on top of the Hayward fault. Our concern is heightened by paleoseismic studies suggesting that the recurrence interval for the past five earthquakes on the southern Hayward fault is 140 to 170 years. Our objective is to build an educational web site that illustrates the cause and effect of the 1868 earthquake drawing on scientific and historic information. We will use Google EarthTM software to visually illustrate complex scientific concepts in a way that is understandable to a non-scientific audience. This web site will lead the viewer from a regional summary of the plate tectonics and faulting system of western North America, to more specific information about the 1868 Hayward earthquake itself. Text and Google EarthTM layers will include modeled shaking of the earthquake, relocations of historic photographs, reconstruction of damaged buildings as 3-D models, and additional scientific data that may come from the many scientific studies conducted for the 140th anniversary of the event. Earthquake engineering concerns will be stressed, including population density, vulnerable infrastructure, and lifelines. We will also present detailed maps of the Hayward fault, measurements of fault creep, and geologic evidence of its recurrence. Understanding the science behind earthquake hazards is an important step in preparing for the next significant earthquake. We hope to communicate to the public and students of all ages, through visualizations, not only the cause and effect of the 1868 earthquake, but also modern seismic hazards of the San Francisco Bay region.

A Report Of The December 6, 2016 Mw 6.5 Pidie Jaya, Aceh Earthquake

NASA Astrophysics Data System (ADS)

Muzli, M.; Daniarsyad, G.; Nugraha, A. D.; Muksin, U.; Widiyantoro, S.; Bradley, K.; Wang, T.; Jousset, P. G.; Erbas, K.; Nurdin, I.; Wei, S.

2017-12-01

The December 6, 2016 Mw 6.5 earthquake in Pidie Jaya, Aceh was one of the devastating inland earthquakes in Sumatra that took away more than 100 people's life. Here we present our seismological analysis of the earthquake sequence. The earthquake focal mechanism inversions using regional BMKG broadband data and teleseismic waveform data all indicate a strike-slip focal mechanism with a centroid depth of 15 km. Preliminary finite fault inversion using teleseismic body waves prefers the fault plane with strike of 45 degree and dip of 50 degree, in agreement with the surface geology and USGS aftershock distributions. Nine broadband seismic stations were installed in the source region along the coast one week after the earthquake and have collected the data for one month. The data have been used to locate aftershocks with grid search and double-difference algorithm, which results in the lineup of the seismicity in NE-SW direction, in agreement with the fault inversion and geology results. Using the M4.0 calibration earthquake that was recorded by the temporally network, we relocated the mainshock epicenter, which is also consistent with fault geometry defined by the well located aftershocks. In addition, a portion of the seismicity shows a lineation in E-W direction, indicating a secondary fault that has not been identified before. Aftershock focal mechanisms determined by the first motion reveal similar solutions as the mainshock. The observed macro intensity data shows most of the damaged buildings are distributed along the coast, approximately perpendicular to the preferred fault strike instead of parallel with it. It appears that the distribution of damage is strongly related to the site conditions, since these strong shaking/damage regions are mainly located on the costal sedimentary soils.

A discussion of the socio-economic losses and shelter impacts from the Van, Turkey Earthquakes of October and November 2011

NASA Astrophysics Data System (ADS)

Daniell, J. E.; Khazai, B.; Wenzel, F.; Kunz-Plapp, T.; Vervaeck, A.; Muehr, B.; Markus, M.

2012-04-01

The Van earthquake in 2011 hit at 10:41 GMT (13:41 Local) on Sunday, October 23rd, 2011. It was a Mw7.1-7.3 event located at a depth of around 10 km with the epicentre located directly between Ercis (pop. 75,000) and Van (pop. 370,000). Since then, the CEDIM Forensic Analysis Group (using a team of seismologists, engineers, sociologists and meteorologists) and www.earthquake-report.com has reported and analysed on the Van event. In addition, many damaging aftershocks occurring after the main eventwere analysed including a major aftershock centered in Van-Edremit on November 9th, 2011, causing much additional losses. The province of Van has around 1.035 million people as of the last census. The Van province is one of the poorest in Turkey and has much inequality between the rural and urban centers with an average HDI (Human Development Index) around that of Bhutan or Congo. The earthquakes are estimated to have caused 604 deaths (23 October) and 40 deaths (9 November); mostly due to falling debris and house collapse). In addition, between 1 billion TRY to 4 billion TRY (approx. 555 million USD - 2.2 billion USD) is estimated as total economic losses. This represents around 17 to 66% of the provincial GDP of the Van Province (approx. 3.3 billion USD) as of 2011. From the CATDAT Damaging Earthquakes Database, major earthquakes such as this one have occurred in the year 1111 causing major damage and having a magnitude around 6.5-7. In the year 1646 or 1648, Van was again struck by a M6.7 quake killing around 2000 people. In 1881, a M6.3 earthquake near Van killed 95 people. Again, in 1941, a M5.9 earthquake affected Ercis and Van killing between 190 and 430 people. 1945-1946 as well as 1972 brought again damaging and casualty-bearing earthquakes to the Van province. In 1976, the Van-Muradiye earthquake struck the border region with a M7, killing around 3840 people and causing around 51,000 people to become homeless. Key immediate lessons from similar historic earthquakes in eastern Turkey were developed in terms of the mass shelter and post-earthquake housing needs of the displaced population of Van. This included an analysis of shelter and reconstruction requirements under winter weather conditions; community resourcefulness in coping with housing needs through indigenous methods; and issues with in-place sheltering versus relocation and resettlement. A summary of the losses and implications on the GDP, economic dynamics, capital stock, social structure shelter and housing needs of the region is discussed. In addition, a quick comparison to past similar earthquakes is undertaken through the use of CATDAT.

Healing of the landscape after Gorkha earthquake, insights from seismic interferometry

NASA Astrophysics Data System (ADS)

Illien, Luc; Sens-Schönfelder, Christoph; Hovius, Niels; Andermann, Christoff; Turowski, Jens Martin

2017-04-01

It has been shown that earthquakes trigger transient effects in the landscape that can last from several days (enhanced river discharge) to several years (enhanced landslides rates) or even decades (e.g. river bedload). These observations are geomorphic expressions of physical changes in shallow subsurface that are yet poorly understood. To gain insights in the underlying physical processes, we appeal to exploratory geophysical methods that allow us to monitor the variation of rock strength over time. Thanks to a seismic dense array deployed in the Bhote Koshi catchment following the April 2015 7.8 Mw Gorkha (Nepal) earthquake we can apply noise correlation monitoring the evolution of the seismic wave velocities at a high spatial resolution in the landscape. Our results show that the observed velocity changes are spatially heterogeneous after ground shaking events. We attribute these velocity changes to coseismic damage that is followed by a recovery in rock strength in the sampled medium. We suggest that these results directly reflect the state of the most fractured layer in the landscape, in the shallow sub-surface. These findings allow us to discuss where erosion patterns such as landslide-prone areas cluster but also mechanisms responsible for hillslope healing after large earthquakes. Finally, this study highlights the value of seismometers for the investigation of near-surface processes in the context of natural hazards.

Applicability and economic efficiency of earthquake retrofit measures on existing buildings in Bucharest, Romania

NASA Astrophysics Data System (ADS)

Bostenaru, M.

2009-04-01

The research discussed in this contribution contains two aspects: on one side the economic efficiency of seismic retrofit measures, and on the other their applicability. The research was limited to housing buildings. Bucharest, the capital of Romania, was the object of the research. Strong earthquakes affect Bucharest about three times in a century, the damaging earthquakes of the 20th century being in 1940 and 1977. Other strong earthquakes occurred in 1986 and 1990. Since it is a broad topic, first the building type was determined, which should serve further research. For this scope the building types of the 20th century, which are common in Bucharest, Romania, were investigated. For each building type reports have been written, which comprised the earthquake resilient features, the seismic defficiencies, the damage patterns and the retrofit measures. Each of these features was listed for elements of the building. A first result of the research was an integrated system in order to include latter aspects in the planning in the first steps. So already at the building survey attention has to be paid on how a building is subdivided in order to be able to determine the economic efficiency of the planned action. So were defined the `retrofit elements`. In a first step the characteristics were defined, through which these retrofit elements (for example column, wall part between two windows) can be recognised in the building survey. In a further one, which retrofit measures can be connected to these. Diagrams were built, in order to visualise these findings. For each retrofit element and the corresponding measure the costs were calculated. Also, these retrofit elements and the measures connected to them were modelled for the simulation with the structural software, so that the benefit of the measures could be determined. In the part which regarded the economic efficiency, benefits and costs of retrofit measures had to be compared, so the improvement in the rigidity, ductility and/or strength of the structure at different retrofit measures with its costs. In order to investigate the improvement in the seismic characteristics numerous simulations of the earthquake impact on reinforced concrete frame buildings were conducted and in that context conventional strengthening measures with reinforced concrete and steel were considered. In these reinforced concrete frame buildings interwar buildings from Bucharest were modelled, as these proved to be the most vulnerable in the initial investigation. For the investigation of the economic efficiency also the damages through earthquakes were simulated. With help of a characteristic of the software used so called performance points could be set, so at the end of the simulation it could be seen how strongly was damaged the steel and respectively the concrete in the reinforced concrete element and so was conducted a classification of the strength of the damages in different retrofit elements. These simulations were done for the 1977, 1986 and 1990 earthquakes, as for these the strong motion records were digitally available. For two simple models alternatives of retrofit actions and their locations were fully simulated, while for real building models customised retrofit strategies considering more retrofit elements within the strategy were employed. To the benefit belong not only the improvement of the structural behaviour, as often assumed in earthquake engineering circles. There belong also aesthetical and sociologic aspects. In order to give these aspects their rights, a decision tree was developed, in which the actors are the engineer, the architect, the investor and the user. The retrofit measures were evaluated with two different decision systems. This was the part about the applicability. Further research would serve to see how can be used the developed method for the strategic planning, in which not only single buildings but whole urban areas build the object. The research was funded by the Research Training Network 450 "Natural Disasters" supported by the DFG (German Research Network), 2000-2004 while the result was published with support from a subsequent research project of the author, CA'REDIVIVUS, which continued the research, supported by the European Commission, in 2006.

Fault zone structure and kinematics from lidar, radar, and imagery: revealing new details along the creeping San Andreas Fault

NASA Astrophysics Data System (ADS)

DeLong, S.; Donnellan, A.; Pickering, A.

2017-12-01

Aseismic fault creep, coseismic fault displacement, distributed deformation, and the relative contribution of each have important bearing on infrastructure resilience, risk reduction, and the study of earthquake physics. Furthermore, the impact of interseismic fault creep in rupture propagation scenarios, and its impact and consequently on fault segmentation and maximum earthquake magnitudes, is poorly resolved in current rupture forecast models. The creeping section of the San Andreas Fault (SAF) in Central California is an outstanding area for establishing methodology for future scientific response to damaging earthquakes and for characterizing the fine details of crustal deformation. Here, we describe how data from airborne and terrestrial laser scanning, airborne interferometric radar (UAVSAR), and optical data from satellites and UAVs can be used to characterize rates and map patterns of deformation within fault zones of varying complexity and geomorphic expression. We are evaluating laser point cloud processing, photogrammetric structure from motion, radar interferometry, sub-pixel correlation, and other techniques to characterize the relative ability of each to measure crustal deformation in two and three dimensions through time. We are collecting new and synthesizing existing data from the zone of highest interseismic creep rates along the SAF where a transition from a single main fault trace to a 1-km wide extensional stepover occurs. In the stepover region, creep measurements from alignment arrays 100 meters long across the main fault trace reveal lower rates than those in adjacent, geomorphically simpler parts of the fault. This indicates that deformation is distributed across the en echelon subsidiary faults, by creep and/or stick-slip behavior. Our objectives are to better understand how deformation is partitioned across a fault damage zone, how it is accommodated in the shallow subsurface, and to better characterize the relative amounts of fault creep and potential stick-slip fault behavior across the plate boundary at these sites in order to evaluate the potential for rupture propagation in large earthquakes.

Irian Jaya earthquake and tsunami cause serious damage

NASA Astrophysics Data System (ADS)

Imamura, Fumihiko; Subandono, D.; Watson, G.; Moore, A.; Takahashi, T.; Matsutomi, H.; Hidayat, R.

On February 17,1996, at 0559 UT, a major earthquake with moment magnitude (Mw) 7.9 killed 107 people and caused major damage at Biak Island, 30-40 km southwest of the earthquake's epicenter (Figures 1 and 2). A devastating tsunami washed away all of the houses at Korim, a small village located in a narrow bay facing directly towards the incoming wave, and it left behind clear evidence of sand erosion and deposition that indicated how far the tsunami advanced. An unexpectedly large tsunami run-up of 7.7 m was measured at Wardo in western Biak, which faces away from the primary tsunami source. This high run-up may have been caused by a local submarine landslide.

In the shadow of 1857-the effect of the great Ft. Tejon earthquake on subsequent earthquakes in southern California

USGS Publications Warehouse

Harris, R.A.; Simpson, R.W.

1996-01-01

The great 1857 Fort Tejon earthquake is the largest earthquake to have hit southern California during the historic period. We investigated if seismicity patterns following 1857 could be due to static stress changes generated by the 1857 earthquake. When post-1857 earthquakes with unknown focal mechanisms were assigned strike-slip mechanisms with strike and rake determined by the nearest active fault, 13 of the 13 southern California M???5.5 earthquakes between 1857 and 1907 were encouraged by the 1857 rupture. When post-1857 earthquakes in the Transverse Ranges with unknown focal mechanisms were assigned reverse mechanisms and all other events were assumed strike-slip, 11 of the 13 earthquakes were encouraged by the 1857 earthquake. These results show significant correlations between static stress changes and seismicity patterns. The correlation disappears around 1907, suggesting that tectonic loading began to overwhelm the effect of the 1857 earthquake early in the 20th century.

A probabilistic estimate of maximum acceleration in rock in the contiguous United States

USGS Publications Warehouse

Algermissen, Sylvester Theodore; Perkins, David M.

1976-01-01

This paper presents a probabilistic estimate of the maximum ground acceleration to be expected from earthquakes occurring in the contiguous United States. It is based primarily upon the historic seismic record which ranges from very incomplete before 1930 to moderately complete after 1960. Geologic data, primarily distribution of faults, have been employed only to a minor extent, because most such data have not been interpreted yet with earthquake hazard evaluation in mind.The map provides a preliminary estimate of the relative hazard in various parts of the country. The report provides a method for evaluating the relative importance of the many parameters and assumptions in hazard analysis. The map and methods of evaluation described reflect the current state of understanding and are intended to be useful for engineering purposes in reducing the effects of earthquakes on buildings and other structures.Studies are underway on improved methods for evaluating the relativ( earthquake hazard of different regions. Comments on this paper are invited to help guide future research and revisions of the accompanying map.The earthquake hazard in the United States has been estimated in a variety of ways since the initial effort by Ulrich (see Roberts and Ulrich, 1950). In general, the earlier maps provided an estimate of the severity of ground shaking or damage but the frequency of occurrence of the shaking or damage was not given. Ulrich's map showed the distribution of expected damage in terms of no damage (zone 0), minor damage (zone 1), moderate damage (zone 2), and major damage (zone 3). The zones were not defined further and the frequency of occurrence of damage was not suggested. Richter (1959) and Algermissen (1969) estimated the ground motion in terms of maximum Modified Mercalli intensity. Richter used the terms "occasional" and "frequent" to characterize intensity IX shaking and Algermissen included recurrence curves for various parts of the country in the paper accompanying his map.The first probabilistic hazard maps covering portions of the United States were by Milne and Davenport (1969a). Recently, Wiggins, Hirshberg and Bronowicki (1974) prepared a probabilistic map of maximum particle velocity and Modified Mercalli intensity for the entire United States. The maps are based on an analysis of the historical seismicity. In general, geological data were not incorporated into the development of the maps.

[Carbon source metabolic diversity of soil microbial community under different climate types in the area affected by Wenchuan earthquake].

PubMed

Zhang, Guang-Shuai; Lin, Yong-Ming; Ma, Rui-Feng; Deng, Hao-Jun; Du, Kun; Wu, Cheng-Zhen; Hong, Wei

2015-02-01

The MS8.0 Wenchuan earthquake in 2008 led to huge damage to land covers in northwest Sichuan, one of the critical fragile eco-regions in China which can be divided into Semi-arid dry hot climate zone (SDHC) and Subtropical humid monsoon climate zone (SHMC). Using the method of Bilog-ECO-microplate technique, this paper aimed to determine the functional diversity of soil microbial community in the earthquake-affected areas which can be divided into undamaged area (U), recover area (R) and damaged area without recovery (D) under different climate types, in order to provide scientific basis for ecological recovery. The results indicated that the average-well-color-development (AWCD) in undamaged area and recovery area showed SDHC > SHMC, which was contrary to the AWCD in the damaged area without recovery. The AWCD of damaged area without recovery was the lowest in both climate zones. The number of carbon source utilization types of soil microbial in SHMC zone was significantly higher than that in SDHC zone. The carbon source utilization types in both climate zones presented a trend of recover area > undamaged area > damaged area without recovery. The carbon source metabolic diversity characteristic of soil microbial community was significantly different in different climate zones. The diversity index and evenness index both showed a ranking of undamaged area > recover area > damaged area without recovery. In addition, the recovery area had the highest richness index. The soil microbial carbon sources metabolism characteristic was affected by soil nutrient, aboveground vegetation biomass and vegetation coverage to some extent. In conclusion, earthquake and its secondary disasters influenced the carbon source metabolic diversity characteristic of soil microbial community mainly through the change of aboveground vegetation and soil environmental factors.

Re-examining the cause of the "Damage Belt" during the 1995 Kobe Earthquake

NASA Astrophysics Data System (ADS)

Matsushima, S.; Miyake, H.

2017-12-01

The 1995 Kobe earthquake caused devastating disaster which killed 6434 people and collapsed more than 1 million houses. The heavy damage was concentrated in a belt-like area, which was called the "Damage Belt". The cause of the "Damage Belt" was investigated by various researchers and it was found that it was a result of "The Basin-Edge Effect", which is the constructive interference of the direct S-wave with the basin-induced diffracted Rayleigh waves (Kawase, 1996). Matsushima and Kawase (2009) estimated the rupture model of the 1995 Kobe Earthquake by using 3-D reciprocal Green's functions and searching for the best fitting case by grid-search technique assuming plural rectangular strong motion generation areas (SMGAs) and succeeded to reproduce the high PGV area that corresponds to the "Damage Belt". In this study, we re-examine the cause of the "Damage Belt" by combining the estimated rupture model with the up-to-date 3-D velocity structure. The velocity structure of whole Japan has been modeled and is being modified occasionally by the Headquarters for Earthquake Research Promotion using the geological surveys conducted thoroughly by local governments as well as by large research projects since 1995. The very detailed velocity structure of the Osaka basin has been modeled by the Geological Survey of Japan, AIST (Horikawa et al., 2003; Sekiguchi et al., 2008). The aim of this study is to take in account of the different amplification characteristics due to the different velocity structure of the sediment from the seismic bedrock to the surface in Kobe, and investigate its effect to the results of the distribution of PGVs of the simulated ground motions.

Multicomponent seismic loss estimation on the North Anatolian Fault Zone (Turkey)

NASA Astrophysics Data System (ADS)

karimzadeh Naghshineh, S.; Askan, A.; Erberik, M. A.; Yakut, A.

2015-12-01

Seismic loss estimation is essential to incorporate seismic risk of structures into an efficient decision-making framework. Evaluation of seismic damage of structures requires a multidisciplinary approach including earthquake source characterization, seismological prediction of earthquake-induced ground motions, prediction of structural responses exposed to ground shaking, and finally estimation of induced damage to structures. As the study region, Erzincan, a city on the eastern part of Turkey is selected which is located in the conjunction of three active strike-slip faults as North Anatolian Fault, North East Anatolian Fault and Ovacik fault. Erzincan city center is in a pull-apart basin underlain by soft sediments that has experienced devastating earthquakes such as the 27 December 1939 (Ms=8.0) and the 13 March 1992 (Mw=6.6) events, resulting in extensive amount of physical as well as economical losses. These losses are attributed to not only the high seismicity of the area but also as a result of the seismic vulnerability of the constructed environment. This study focuses on the seismic damage estimation of Erzincan using both regional seismicity and local building information. For this purpose, first, ground motion records are selected from a set of scenario events simulated with the stochastic finite fault methodology using regional seismicity parameters. Then, existing building stock are classified into specified groups represented with equivalent single-degree-of-freedom systems. Through these models, the inelastic dynamic structural responses are investigated with non-linear time history analysis. To assess the potential seismic damage in the study area, fragility curves for the classified structural types are derived. Finally, the estimated damage is compared with the observed damage during the 1992 Erzincan earthquake. The results are observed to have a reasonable match indicating the efficiency of the ground motion simulations and building analyses.

Estimating the Locations of Past and Future Large Earthquake Ruptures using Recent M4 and Greater Events

NASA Astrophysics Data System (ADS)

Ebel, J.; Chambers, D. W.

2017-12-01

Although most aftershock activity dies away within months or a few years of a mainshock, there is evidence that aftershocks still occur decades or even centuries after mainshocks, particularly in areas of low background seismicity such as stable continental regions. There also is evidence of long-lasting aftershock sequences in California. New work to study the occurrences of recent M≥4 in California shows that these events occur preferentially at the edges of past major ruptures, with the effect lessening with decreasing magnitude below M4. Prior to several California mainshocks, the M≥4 seismicity was uniformly spread along the future fault ruptures without concentrations at the fault ends. On these faults, the rates of the M≥4 earthquakes prior to the mainshocks were much greater than the rates of the recent M≥4 earthquakes. These results suggest that the spatial patterns and rates of M≥4 earthquakes may help identify which faults are most prone to rupturing in the near future. Using this idea, speculation on which faults in California may be the next ones to experience major earthquakes is presented. Some Japanese earthquakes were also tested for the patterns of M≥4 earthquake seen in California. The 2000 Mw6.6 Western Tottori earthquake shows a premonitory pattern similar to the patterns seen in California, and there have not been any M≥4 earthquakes in the fault vicinity since 2010. The 1995 Mw6.9 Kobe earthquake had little M≥4 seismicity in the years prior to the mainshock, and the M≥4 seismicity since 2000 has been scattered along the fault rupture. Both the 2016 M7.3 Kumamoto, Kyushu earthquake and the 2016 Mw6.2 Central Tottori earthquake had some M≥4 earthquakes along the fault in the two decades before the mainshocks. The results of these analyses suggest that the locations of recent M≥4 earthquakes may be useful for determining the spatial extents of past earthquake ruptures and also may help indicate which faults may have strong earthquakes within the next decade or so.

Rapid Response Products of The ARIA Project for the M6.0 August 24, 2014 South Napa Earthquake

NASA Astrophysics Data System (ADS)

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

2014-12-01

A magnitude 6.0 earthquake struck southern Napa county northeast of San Francisco, California, on Aug. 24, 2014, causing significant damage in the city of Napa and nearby areas. One day after the earthquake, the Advanced Rapid Imaging and Analysis (ARIA) team produced and released observations of coseismic ground displacement measured with continuous GPS stations of the Plate Boundary Observatory (operated by UNAVCO for the National Science Foundation) and the Bay Area Rapid Deformation network (operated by Berkeley Seismological Laboratory). Three days after the earthquake (Aug. 27), the Italian Space Agency's (ASI) COSMO-SkyMed (CSK) satellite acquired their first post-event data. On the same day, the ARIA team, in collaboration with ASI and University of Basilicata, produced and released a coseismic interferogram that revealed ground deformation and surface rupture. The depiction of the surface rupture - discontinuities of color fringes in the CSK interferogram - helped guide field geologists from the US Geological Survey and the California Geological Survey (CGS) to features that may have otherwise gone undetected. Small-scale cracks were found on a runway of the Napa County Airport, as well as bridge damage and damaged roads. ARIA's response to this event highlighted the importance of timeliness for mapping surface deformation features. ARIA's rapid response products were shared through Southern California Earthquake Center's response website and the California Earthquake Clearinghouse. A damage proxy map derived from InSAR coherence of CSK data was produced and distributed on Aug. 27. Field crews from the CGS identified true and false positives, including mobile home damage, newly planted grape vines, and a cripple wall failure of a house. Finite fault slip models constrained from CSK interferograms and continuous GPS observations reveal a north-propagating rupture with well-resolved slip from 0-10.5 km depth. We also measured along-track coseismic displacements of about -30 to 30 cm, along the main surface rupture, using multiple aperture interferometry and SAR pixel offset calculation. We also processed the European Space Agency's Sentinel-1A data on Sep. 3 and compared the result with the CSK interferogram, finding a general agreement between the two observations of surface deformation.

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

NASA Astrophysics Data System (ADS)

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

2017-08-01

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

The race to seismic safety : protecting California's transportation system.

DOT National Transportation Integrated Search

2003-12-01

Will future California earthquakes again cause destruction of portions of Californias transportation system, or will their impacts be controlled to limit the damage and disruption any large earthquake will cause? This is the key question addressed...

Social, not physical, infrastructure: the critical role of civil society after the 1923 Tokyo earthquake.

PubMed

Aldrich, Daniel P

2012-07-01

Despite the tremendous destruction wrought by catastrophes, social science holds few quantitative assessments of explanations for the rate of recovery. This article illuminates four factors-damage, population density, human capital, and economic capital-that are thought to explain the variation in the pace of population recovery following disaster; it also explores the popular but relatively untested factor of social capital. Using time-series, cross-sectional models and propensity score matching, it tests these approaches using new data from the rebuilding of 39 neighbourhoods in Tokyo after its 1923 earthquake. Social capital, more than earthquake damage, population density, human capital, or economic capital, best predicts population recovery in post-earthquake Tokyo. These findings suggest new approaches for research on social capital and disasters as well as public policy avenues for handling catastrophes. © 2012 The Author(s). Journal compilation © Overseas Development Institute, 2012.

Field survey of the March 28, 2005 Nias-Simeulue earthquake and Tsunami

USGS Publications Warehouse

Borrero, J.C.; McAdoo, B.; Jaffe, B.; Dengler, L.; Gelfenbaum, G.; Higman, B.; Hidayat, R.; Moore, A.; Kongko, W.; ,; Peters, R.; Prasetya, G.; Titov, V.; Yulianto, E.

2011-01-01

On the evening of March 28, 2005 at 11:09 p.m. local time (16:09 UTC), a large earthquake occurred offshore of West Sumatra, Indonesia. With a moment magnitude (Mw) of 8.6, the event caused substantial shaking damage and land level changes between Simeulue Island in the north and the Batu Islands in the south. The earthquake also generated a tsunami, which was observed throughout the source region as well as on distant tide gauges. While the tsunami was not as extreme as the tsunami of December 26th, 2004, it did cause significant flooding and damage at some locations. The spatial and temporal proximity of the two events led to a unique set of observational data from the earthquake and tsunami as well as insights relevant to tsunami hazard planning and education efforts. ?? 2010 Springer Basel AG.

Selected Images of the Effects of the October 15, 2006, Kiholo Bay-Mahukona, Hawai'i, Earthquakes and Recovery Efforts

USGS Publications Warehouse

Takahashi, Taeko Jane; Ikeda, Nancy A.; Okubo, Paul G.; Sako, Maurice K.; Dow, David C.; Priester, Anna M.; Steiner, Nolan A.

2011-01-01

Although the vast majority of earthquakes in the State of Hawaii are closely related to the active volcanism associated with the southeastern part of the Island of Hawai‘i, the October 2006 Kīholo Bay and Māhukona earthquakes clearly suggest the devastating potential of deeper lithospheric earthquakes. Large earthquakes thought to be nearly M7 have struck near the islands of Lāna‘i (1871) and Maui (1938). It is thought that these, like the 2006 earthquakes, were deep lithospheric flexure earthquakes (Wyss and Koyanagi, 1992; Klein and others, 2001). Thus, it is important to recognize the potential seismic hazard posed by such earthquakes beneath the older Hawaiian Islands. The data and observations afforded by the 2006 earthquakes promise to improve probabilistic seismic hazards modeling in Hawai‘i. The effects of the October 15, 2006, Kīholo Bay-Māhukona earthquakes are shown in images taken from the coastal route along the northern half of the Island of Hawai‘i, where damage was the most concentrated. The direction of presentation is counter-clockwise, from Pa‘auilo on the eastern or windward (Hāmākua) side to Kealakekua Bay on the western or leeward (Kona) side. A list of sites, their locations, coordinates, and distance from the epicenter at Kīholo Bay are given in table 1. A Google Earth map (fig. 7) and a topographic map (fig. 8) pinpoint the 36 sites where damage was documented and digital images were compiled for this collection.

Flashsourcing or Real-Time Mapping of Earthquake Effects from Instantaneous Analysis of the EMSC Website Traffic

NASA Astrophysics Data System (ADS)

Bossu, R.; Gilles, S.; Roussel, F.

2010-12-01

Earthquake response efforts are often hampered by the lack of timely and reliable information on the earthquake impact. Rapid detection of damaging events and production of actionable information for emergency response personnel within minutes of their occurrence are essential to mitigate the human impacts from earthquakes. Economically developed countries deploy dense real-time accelerometric networks in regions of high seismic hazard to constrain scenarios from in-situ data. A cheaper alternative, named flashsourcing, is based on implicit data derived from the analysis of the visits by eyewitnesses, the first informed persons, to websites offering real time earthquake information. We demonstrated in 2004 that widely felt earthquakes generate a surge of traffic, known as a flashcrowd, caused by people rushing websites such as the EMSC’s to find information about the shaking they have just felt. With detailed traffic analysis and metrics, widely felt earthquakes can be detected within one minute of the earthquake’s occurrence. In addition, the geographical area where the earthquake has been felt is automatically mapped within 5 minutes by statistically analysing the IP locations of the eyewitnesses, without using any seismological data. These results have been validated on more than 150 earthquakes by comparing the automatic felt maps with the felt area derived from macroseismic questionnaires. In practice, the felt maps are available before the first location is published by the EMSC. We have also demonstrated the capacity to rapidly detect and map areas of widespread damage by detecting when visitors suddenly end their sessions on the website en masse. This has been successfully applied to time and map the massive power failure which plunged a large part of Chile into darkness in March, 2010. If damage to power and communication lines cannot be discriminated from damage to buildings, the absence of sudden session closures precludes the possibility of heavy damage and provides further constraints to seismic scenarios. To better discriminate in case of large-scale session closure, we propose to analyze cell phone connections, whose networks may remain viable when land lines have gone down. This presentation aims to give an overview of the potential of this technique which is today the fastest way to collect in-situ information on an earthquake’s effects. It also provides insightful information about the actual reaction of the population after experiencing an earthquake. There are indications that the relative level of shaking for a given event could be estimated through the ratio of actual visitors to the number of inhabitants. By focusing on the reaction of the population rather than the parameters of the seismic source, it identifies what is perceived as an important event by the public regardless its magnitude. Typical examples are low magnitude earthquakes located close to large cities, like the M2.8 located beneath Sofia, Bulgaria, on Aug. 27, 2010. Based on implicit data, the results cannot be easily altered, which differs from other user-generated content where reliability assessment remains essential. This mechanism is an extension of complementary crowdsourcing techniques such as online questionnaires, applied on flash crowds, leading to its name flashsourcing.

Support Needs of the Survivors of the August 17, 1999 Earthquake in Turkey

ERIC Educational Resources Information Center

Kasapoglu, Aytul; Ecevit, Yildiz; Ecevit, Mehmet

2004-01-01

This paper aims to present a sociological analysis of social support related to disaster sociology in general and earthquakes specifically. The analysis is based on field research conducted a year after the 17 August 1999 East Marmara earthquake where 18,000 people died; 50,000 people injured; 5000 buildings collapsed and 340,000 of them damaged;…

Utah braces for the future

USGS Publications Warehouse

Machette, Michael N.; Brown, William M.

1995-01-01

Almost 75 percent of Utah's population lives near the Wasatch Fault. Earth scientists have shown that this fault has repeatedly experienced strong earthquakes of magnitude 7 or larger and will continue to do so in the future. Efforts to increase public awareness of earthquake hazards in Utah have resulted in residents and community leaders taking actions that will save lives and reduce damage in future earthquakes.

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

NASA Astrophysics Data System (ADS)

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

2017-12-01

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

Earthquake history of the Republic of Ragusa (today Dubrovnik, Croatia) (Invited)

NASA Astrophysics Data System (ADS)

Albini, P.; Rovida, A.; Locati, M.

2009-12-01

Among the towns constellating the Dalmatian coast, Ragusa (today Dubrovnik, Croatia), stands out, both because of its location in the middle of the Eastern Adriatic coast and its long-lasting, independent history of a Modern Age town and its small coastal territory. An important intelligence crossroads, squeezed as it was in between powerful and influential neighbours, such as the Ottoman Empire and the Republic of Venice, in its history (1358-1808) the Republic of Ragusa did experience heavily damaging earthquakes. We narrate the story of these earthquakes, which were recorded in the historical documentation of the Republic (today stored at the State Archives of Dubrovnik - Drzavni arhiv u Dubrovniku) as well as in documents from officers of other Mediterranean countries and letters of individuals. Of special note is the 6 April 1667 earthquake, which inflicted a permanent scar on the Republic. The earthquake's direct effects and their consequences caused a serious financial crisis, so critical that it took over 50 years for Ragusa to recover. This large earthquake is reappraised on the basis of newly investigated sources, and effects of the damage within the city walls are detailed. A seismic history of Ragusa is finally proposed, supported by full-text coeval records.

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 to the NSHM scenario were developed for the Hilton Creek and Hartley Springs Faults to account for different opinions in how far these two faults extend into Long Valley Caldera. For each scenario, ground motions were calculated using the current standard practice: the deterministic seismic hazard analysis program developed by Art Frankel of USGS and three Next Generation Ground Motion Attenuation (NGA) models. Ground motion calculations incorporated the potential amplification of seismic shaking by near-surface soils defined by a map of the average shear wave velocity in the uppermost 30 m (VS30) developed by CGS.In addition to ground shaking and shaking-related ground failure such as liquefaction and earthquake induced landslides, earthquakes cause surface rupture displacement, which can lead to severe damage of buildings and lifelines. For each earthquake scenario, potential surface fault displacements are estimated using deterministic and probabilistic approaches. Liquefaction occurs when saturated sediments lose their strength because of ground shaking. Zones of potential liquefaction are mapped by incorporating areas where loose sandy sediments, shallow groundwater, and strong earthquake shaking coincide in the earthquake scenario. The process for defining zones of potential landslide and rockfall incorporates rock strength, surface slope, and existing landslides, with ground motions caused by the scenario earthquake.Each scenario is illustrated with maps of seismic shaking potential and fault displacement, liquefaction, and landslide potential. Seismic shaking is depicted by the distribution of shaking intensity, peak ground acceleration, and 1.0-second spectral acceleration. One-second spectral acceleration correlates well with structural damage to surface facilities. Acceleration greater than 0.2 g is often associated with strong ground shaking and may cause moderate to heavy damage. The extent of strong shaking is influenced by subsurface fault dip and near surface materials. Strong shaking is more widespread in the hanging wall regions of a normal fault. Larger ground motions also occur where young alluvial sediments amplify the shaking. Both of these effects can lead to strong shaking that extends farther from the fault on the valley side than on the hill side.The effect of fault rupture displacements may be localized along the surface trace of the mapped earthquake fault if fault geometry is simple and the fault traces are accurately located. However, surface displacement hazards can spread over a few hundred meters to a few kilometers if the earthquake fault has numerous splays or branches, such as the Hilton Creek Fault. Faulting displacements are estimated to be about 1 meter along normal faults in the study area and close to 2 meters along the White Mountains Fault Zone.All scenarios show the possibility of widespread ground failure. Liquefaction damage would likely occur in the areas of higher ground shaking near the faults where there are sandy/silty sediments and the depth to groundwater is 6.1 meters (20 feet) or less. Generally, this means damage is most common near lakes and streams in the areas of strongest shaking. Landslide potential exists throughout the study region. All steep slopes (>30 degrees) present a potential hazard at any level of shaking. Lesser slopes may have landslides within the areas of the higher ground shaking. The landslide hazard zones also are likely sources for snow avalanches during winter months and for large boulders that can be shaken loose and roll hundreds of feet down hill, which happened during the 1980 Mammoth Lakes earthquakes.Whereas methodologies used in estimating ground shaking, liquefaction, and landslides are well developed and have been applied in published hazard maps; methodologies used in estimating surface fault displacement are still being developed. Therefore, this report provides a more in-depth and detailed discussion of methodologies used for deterministic and probabilistic fault displacement hazard analyses for this project.

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.

Historical Earthquake Scenarios and Effects on the Ancient City of İstanbul (A.D. 478 - 1999)

NASA Astrophysics Data System (ADS)

Şahin, Murat; Elitez, İrem; Özmen, Aybars; Yaltırak, Cenk

2016-04-01

Active fault mapping is one of the most important subject in the active tectonic studies. The consistency of the active fault maps with the reality is curial for the settlements and socio-economic conditions. The Marmara region is one of the precious area where the longest duration settlement and civilization are observed along a fault system. The Marmara Sea and its surrounding area are unique on the earth which has the remarkable history of 1500 years in non-instrumental period. Because, İstanbul was the capital city of both Byzantium and Ottoman Empire and the historical records of İstanbul are reliable for this environment such as A.D. 1509 earthquake known as 'little apocalypse'. Although the active faults of the Marmara Sea have studied and mapped by many researchers, there are only three different main fault model suggested for the Marmara Sea. These are single fault model (Le Pichon et al., 2001), pull-apart model (Armijo et al., 2005) and horsetail model (Yaltırak, 2002; 2015). Yaltırak (2015) grouped the 38 destructive historical earthquakes according to their felt area for these three fault models in the Marmara region. In this study we have modelled the Modified Mercalli Intensities (MMI) of historical buildings and cross checked with damages on the related structure in order to investigate the consistency of fault pattern with historical earthquakes. In this study three-stage evaluation has been made. In the first stage, three models that differ from each other were prepared on a database in commercial ArcGIS software. Mw values were calculated for each segment according to their lengths, seismogenic depths and 18 mm/yr accumulation by using the equation of Kanamori (1977). In the second stage, the 1:25000-scale geological map of the ancient city of İstanbul was revised according to Vs30 data of the İstanbul Metropolitan Municipality. The exact location of the historical constructions in the İstanbul have been plotted by using non-commercial high-resolution satellite images and archaeological maps. The third stage is the calculation of g-acceleration by using attenuation relation of Boore et al. (1993 and 1997). In order to calculate the MMI values for this study, we used the PGA-MMI equation of Bilal and Askan (2010). The MMI data sets produced in ArcGIS 10.2 utilized to generate the images by using the Generic Mapping Tool (GMT). In conclusion, one of the fault patterns (Le Pichon et al., 2001) has major contradictions with historical earthquake records and the other (Armijo et al., 2005) has incompatibilities with records as much as the first one. The remarkable correlation between the active faults and the damages of historical earthquakes on the constructions in ancient city of İstanbul is observed in the third model (Yaltırak, 2002; 2015).

Use of external fixators for damage-control orthopaedics in natural disasters like the 2005 Pakistan earthquake.

PubMed

Awais, Syed; Saeed, Ayesha; Ch, Asad

2014-08-01

In the 2005 Pakistan earthquake, the great many injured with multiple fractures and open wounds provided a unique opportunity to practice damage-control orthopaedics. External fixators remain a time-tested tools for operating surgeons on such occasions. The locally manufactured, readily available Naseer-Awais (NA) external fixator filled such needs of this disaster with good outcome. This is a retrospective descriptive study of 19,700 patients that presented over seven months to the two centres established by the lead author (SMA) in Muzaffarabad and Mansehra just one night after the 2005 earthquake. A series of local and foreign orthopaedic surgeon teams operated in succession. The computerised patient data collection of 1,145 operations was retrospectively analysed. Of the 19,700 patients presenting to the SMA centres, 50% had limb injuries. Total fracture fixations were 1,145, of which 295 were external fixations: 185 were applied on the lower limb and 90 on upper limb, the majority were applied on tibia. External fixators are valuable damage-control tools in natural disasters and warfare injuries. The locally manufactured NA external fixator served the needs of the many limb injuries during the 2005 Pakistan earthquake.

The Alaska earthquake, March 27, 1964: lessons and conclusions

USGS Publications Warehouse

Eckel, Edwin B.

1970-01-01

One of the greatest earthquakes of all time struck south-central Alaska on March 27, 1964. Strong motion lasted longer than for most recorded earthquakes, and more land surface was dislocated, vertically and horizontally, than by any known previous temblor. Never before were so many effects on earth processes and on the works of man available for study by scientists and engineers over so great an area. The seismic vibrations, which directly or indirectly caused most of the damage, were but surface manifestations of a great geologic event-the dislocation of a huge segment of the crust along a deeply buried fault whose nature and even exact location are still subjects for speculation. Not only was the land surface tilted by the great tectonic event beneath it, with resultant seismic sea waves that traversed the entire Pacific, but an enormous mass of land and sea floor moved several tens of feet horizontally toward the Gulf of Alaska. Downslope mass movements of rock, earth, and snow were initiated. Subaqueous slides along lake shores and seacoasts, near-horizontal movements of mobilized soil (“landspreading”), and giant translatory slides in sensitive clay did the most damage and provided the most new knowledge as to the origin, mechanics, and possible means of control or avoidance of such movements. The slopes of most of the deltas that slid in 1964, and that produced destructive local waves, are still as steep or steeper than they were before the earthquake and hence would be unstable or metastable in the event of another great earthquake. Rockslide avalanches provided new evidence that such masses may travel on cushions of compressed air, but a widely held theory that glaciers surge after an earthquake has not been substantiated. Innumerable ground fissures, many of them marked by copious emissions of water, caused much damage in towns and along transportation routes. Vibration also consolidated loose granular materials. In some coastal areas, local subsidence was superimposed on regional tectonic subsidence to heighten the flooding damage. Ground and surface waters were measurably affected by the earthquake, not only in Alaska but throughout the world. Expectably, local geologic conditions largely controlled the extent of structural damage, whether caused directly by seismic vibrations or by secondary effects such as those just described. Intensity was greatest in areas underlain by thick saturated unconsolidated deposits, least on indurated bedrock or permanently frozen ground, and intermediate on coarse well-drained gravel, on morainal deposits, or on moderately indurated sedimentary rocks. Local and even regional geology also controlled the distribution and extent of the earthquake's effects on hydrologic systems. In the conterminous United States, for example, seiches in wells and bodies of surface water were controlled by geologic structures of regional dimension. Devastating as the earthquake was, it had many long-term beneficial effects. Many of these were socioeconomic or engineering in nature; others were of scientific value. Much new and corroborative basic geologic and hydrologic information was accumulated in the course of the earthquake studies, and many new or improved investigative techniques were developed. Chief among these, perhaps, were the recognition that lakes can be used as giant tiltmeters, the refinement of methods for measuring land-level changes by observing displacements of barnacles and other sessile organisms, and the relating of hydrology to seismology by worldwide study of hydroseisms in surface-water bodies and in wells. The geologic and hydrologic lessons learned from studies of the Alaska earthquake also lead directly to better definition of the research needed to further our understanding of earthquakes and of how to avoid or lessen the effects of future ones. Research is needed on the origins and mechanisms of earthquakes, on crustal structure, and on the generation of tsunamis and local waves. Better earthquake-hazard maps, based on improved knowledge of regional geology, fault behavior, and earthquake mechanisms, are needed for the entire country. Their preparation will require the close collaboration of engineers, seismologists, and geologists. Geologic maps of all inhabited places in earthquake-prone parts of the country are also needed by city planners and others, because the direct relationship between local geology and potential earthquake damage is now well understood. Improved and enlarged nets of earthquake-sensing instruments, sited in relation to known geology, are needed, as are many more geodetic and hydrographic measurements. Every large earthquake, wherever located, should be regarded as a full-scale laboratory experiment whose study can give scientific and engineering information unobtainable from any other source. Plans must be made before the event to insure staffing, funding, and coordination of effort for the scientific and engineering study of future earthquakes. Advice of earth scientists and engineers should be used in the decision-making processes involved in reconstruction after any future disastrous earthquake, as was done after the Alaska earthquake. The volume closes with a selected bibliography and a comprehensive index to the entire series of U.S. Geological Survey Professional Papers 541-546. This is the last in a series of six reports that the U.S. Geological Survey published on the results of a comprehensive geologic study that began, as a reconnaissance survey, within 24 hours after the March 27, 1964, Magnitude 9.2 Great Alaska Earthquake and extended, as detailed investigations, through several field seasons. The 1964 Great Alaska earthquake was the largest earthquake in the U.S. since 1700. Professional Paper 546, in 1 part, describes Lessons and Conclusions.

Preliminary Report Summarizes Tsunami Impacts and Lessons Learned from the September 7, 2017, M8.1 Tehuantepec Earthquake

NASA Astrophysics Data System (ADS)

Wilson, R. I.; Ramirez-Herrera, M. T.; Dengler, L. A.; Miller, K.; LaDuke, Y.

2017-12-01

The preliminary tsunami impacts from the September 7, 2017, M8.1 Tehuantepec Earthquake have been summarized in the following report: https://www.eeri.org/wp-content/uploads/EERI-Recon-Rpt-090717-Mexico-tsunami_fn.pdf. Although the tsunami impacts were not as significant as those from the earthquake itself (98 fatalities and 41,000 homes damaged), the following are highlights and lessons learned: The Tehuantepec earthquake was one of the largest down-slab normal faulting events ever recorded. This situation complicated the tsunami forecast since forecast methods and pre-event modeling are primarily associated with megathrust earthquakes where the most significant tsunamis are generated. Adding non-megathrust source modeling to the tsunami forecast databases of conventional warning systems should be considered. Offshore seismic and tsunami hazard analyses using past events should incorporate the potential for large earthquakes occurring along sources other than the megathrust boundary. From an engineering perspective, initial reports indicate there was only minor tsunami damage along the Mexico coast. There was damage to Marina Chiapas where floating docks overtopped their piles. Increasing pile heights could reduce the potential for damage to floating docks. Tsunami warning notifications did not get to the public in time to assist with evacuation. Streamlining the messaging in Mexico from the warning system directly to the public should be considered. And, for local events, preparedness efforts should place emphasis on responding to feeling the earthquake and not waiting to be notified. Although the U.S. tsunami warning centers were timely with their international and domestic messaging, there were some issues with how those messages were presented and interpreted. The use of a "Tsunami Threat" banner on the new main warning center website created confusion with emergency managers in the U.S. where no tsunami threat was expected to exist. Also, some U.S. states and territories in the Pacific were listed in both domestic and international messages, which caused confusion for American Samoa where these messages contained somewhat conflicting information. These issues are being addressed by the warning centers and the U.S. National Tsunami Hazard Mitigation Program.

Multi-Scale Structure and Earthquake Properties in the San Jacinto Fault Zone Area

NASA Astrophysics Data System (ADS)

Ben-Zion, Y.

2014-12-01

I review multi-scale multi-signal seismological results on structure and earthquake properties within and around the San Jacinto Fault Zone (SJFZ) in southern California. The results are based on data of the southern California and ANZA networks covering scales from a few km to over 100 km, additional near-fault seismometers and linear arrays with instrument spacing 25-50 m that cross the SJFZ at several locations, and a dense rectangular array with >1100 vertical-component nodes separated by 10-30 m centered on the fault. The structural studies utilize earthquake data to image the seismogenic sections and ambient noise to image the shallower structures. The earthquake studies use waveform inversions and additional time domain and spectral methods. We observe pronounced damage regions with low seismic velocities and anomalous Vp/Vs ratios around the fault, and clear velocity contrasts across various sections. The damage zones and velocity contrasts produce fault zone trapped and head waves at various locations, along with time delays, anisotropy and other signals. The damage zones follow a flower-shape with depth; in places with velocity contrast they are offset to the stiffer side at depth as expected for bimaterial ruptures with persistent propagation direction. Analysis of PGV and PGA indicates clear persistent directivity at given fault sections and overall motion amplification within several km around the fault. Clear temporal changes of velocities, probably involving primarily the shallow material, are observed in response to seasonal, earthquake and other loadings. Full source tensor properties of M>4 earthquakes in the complex trifurcation area include statistically-robust small isotropic component, likely reflecting dynamic generation of rock damage in the source volumes. The dense fault zone instruments record seismic "noise" at frequencies >200 Hz that can be used for imaging and monitoring the shallow material with high space and time details, and numerous minute local earthquakes that contribute to the high frequency "noise". Updated results will be presented in the meeting. *The studies have been done in collaboration with Frank Vernon, Amir Allam, Dimitri Zigone, Zach Ross, Gregor Hillers, Ittai Kurzon, Michel Campillo, Philippe Roux, Lupei Zhu, Dan Hollis, Mitchell Barklage and others.

Dynamic fracture network around faults: implications for earthquake ruptures, ground motion and energy budget

NASA Astrophysics Data System (ADS)

Okubo, K.; Bhat, H. S.; Rougier, E.; Lei, Z.; Knight, E. E.; Klinger, Y.

2017-12-01

Numerous studies have suggested that spontaneous earthquake ruptures can dynamically induce failure in secondary fracture network, regarded as damage zone around faults. The feedbacks of such fracture network play a crucial role in earthquake rupture, its radiated wave field and the total energy budget. A novel numerical modeling tool based on the combined finite-discrete element method (FDEM), which accounts for the main rupture propagation and nucleation/propagation of secondary cracks, was used to quantify the evolution of the fracture network and evaluate its effects on the main rupture and its associated radiation. The simulations were performed with the FDEM-based software tool, Hybrid Optimization Software Suite (HOSSedu) developed by Los Alamos National Laboratory. We first modeled an earthquake rupture on a planar strike-slip fault surrounded by a brittle medium where secondary cracks can be nucleated/activated by the earthquake rupture. We show that the secondary cracks are dynamically generated dominantly on the extensional side of the fault, mainly behind the rupture front, and it forms an intricate network of fractures in the damage zone. The rupture velocity thereby significantly decreases, by 10 to 20 percent, while the supershear transition length increases in comparison to the one with purely elastic medium. It is also observed that the high-frequency component (10 to 100 Hz) of the near-field ground acceleration is enhanced by the dynamically activated fracture network, consistent with field observations. We then conducted the case study in depth with various sets of initial stress state, and friction properties, to investigate the evolution of damage zone. We show that the width of damage zone decreases in depth, forming "flower-like" structure as the characteristic slip distance in linear slip-weakening law, or the fracture energy on the fault, is kept constant with depth. Finally, we compared the fracture energy on the fault to the energy absorbed by the secondary fracture network to better understand the earthquake energy budget. We conclude that the secondary fracture network plays an important role on the dynamic earthquake rupture, its radiated wave field and the overall energy budget.

Analysis of Landslides Triggered by October 2005, Kashmir Earthquake

PubMed Central

Mahmood, Irfan; Qureshi, Shahid Nadeem; Tariq, Shahina; Atique, Luqman; Iqbal, Muhammad Farooq

2015-01-01

Introduction: The October 2005, Kashmir earthquake main event was triggered along the Balakot-Bagh Fault which runs from Bagh to Balakot, and caused more damages in and around these areas. Major landslides were activated during and after the earthquake inflicting large damages in the area, both in terms of infrastructure and casualties. These landslides were mainly attributed to the minimum threshold of the earthquake, geology of the area, climatologic and geomorphologic conditions, mudflows, widening of the roads without stability assessment, and heavy rainfall after the earthquake. These landslides were mainly rock and debris falls. Hattian Bala rock avalanche was largest landslide associated with the earthquake which completely destroyed a village and blocked the valley creating a lake. Discussion: The present study shows that the fault rupture and fault geometry have direct influence on the distribution of landslides and that along the rupture zone a high frequency band of landslides was triggered. There was an increase in number of landslides due to 2005 earthquake and its aftershocks and that most of earthquakes have occurred along faults, rivers and roads. It is observed that the stability of landslide mass is greatly influenced by amplitude, frequency and duration of earthquake induced ground motion. Most of the slope failures along the roads resulted from the alteration of these slopes during widening of the roads, and seepages during the rainy season immediately after the earthquake. Conclusion: Landslides occurred mostly along weakly cemented and indurated rocks, colluvial sand and cemented soils. It is also worth noting that fissures and ground crack which were induced by main and after shock are still present and they pose a major potential threat for future landslides in case of another earthquake activity or under extreme weather conditions. PMID:26366324

Analysis of Landslides Triggered by October 2005, Kashmir Earthquake.

PubMed

Mahmood, Irfan; Qureshi, Shahid Nadeem; Tariq, Shahina; Atique, Luqman; Iqbal, Muhammad Farooq

2015-08-26

The October 2005, Kashmir earthquake main event was triggered along the Balakot-Bagh Fault which runs from Bagh to Balakot, and caused more damages in and around these areas. Major landslides were activated during and after the earthquake inflicting large damages in the area, both in terms of infrastructure and casualties. These landslides were mainly attributed to the minimum threshold of the earthquake, geology of the area, climatologic and geomorphologic conditions, mudflows, widening of the roads without stability assessment, and heavy rainfall after the earthquake. These landslides were mainly rock and debris falls. Hattian Bala rock avalanche was largest landslide associated with the earthquake which completely destroyed a village and blocked the valley creating a lake. The present study shows that the fault rupture and fault geometry have direct influence on the distribution of landslides and that along the rupture zone a high frequency band of landslides was triggered. There was an increase in number of landslides due to 2005 earthquake and its aftershocks and that most of earthquakes have occurred along faults, rivers and roads. It is observed that the stability of landslide mass is greatly influenced by amplitude, frequency and duration of earthquake induced ground motion. Most of the slope failures along the roads resulted from the alteration of these slopes during widening of the roads, and seepages during the rainy season immediately after the earthquake.  Landslides occurred mostly along weakly cemented and indurated rocks, colluvial sand and cemented soils. It is also worth noting that fissures and ground crack which were induced by main and after shock are still present and they pose a major potential threat for future landslides in case of another earthquake activity or under extreme weather conditions.

The development of damage identification methods for buildings with image recognition and machine learning techniques utilizing aerial photographs of the 2016 Kumamoto earthquake

NASA Astrophysics Data System (ADS)

Shohei, N.; Nakamura, H.; Fujiwara, H.; Naoichi, M.; Hiromitsu, T.

2017-12-01

It is important to get schematic information of the damage situation immediately after the earthquake utilizing photographs shot from an airplane in terms of the investigation and the decision-making for authorities. In case of the 2016 Kumamoto earthquake, we have acquired more than 1,800 orthographic projection photographs adjacent to damaged areas. These photos have taken between April 16th and 19th by airplanes, then we have distinguished damages of all buildings with 4 levels, and organized as approximately 296,000 GIS data corresponding to the fundamental Geospatial data published by Geospatial Information Authority of Japan. These data have organized by effort of hundreds of engineers. However, it is not considered practical for more extensive disasters like the Nankai Trough earthquake by only human powers. So, we have been developing the automatic damage identification method utilizing image recognition and machine learning techniques. First, we have extracted training data of more than 10,000 buildings which have equally damage levels divided in 4 grades. With these training data, we have been raster scanning in each scanning ranges of entire images, then clipping patch images which represents damage levels each. By utilizing these patch images, we have been developing discriminant models by two ways. One is a model using the Support Vector Machine (SVM). First, extract a feature quantity of each patch images. Then, with these vector values, calculate the histogram density as a method of Bag of Visual Words (BoVW), then classify borders with each damage grades by SVM. The other one is a model using the multi-layered Neural Network. First, design a multi-layered Neural Network. Second, input patch images and damage levels based on a visual judgement, and then, optimize learning parameters with error backpropagation method. By use of both discriminant models, we are going to discriminate damage levels in each patches, then create the image that shows building damage situations. It would be helpful for more prompt and widespread damage detection than visual judgement. Acknowledgment: This work was supported by CSTI through the Cross-ministerial Strategic Innovation Promotion Program (SIP), titled "Enhancement of societal resiliency against natural disasters"(Funding agency: JST).

Google earth mapping of damage from the Nigata-Ken-Chuetsu M6.6 earthquake of 16 July 2007

USGS Publications Warehouse

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

2008-01-01

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

Tsunami Field Survey for the Solomon Islands Earthquake of April 1, 2007

NASA Astrophysics Data System (ADS)

Nishimura, Y.; Tanioka, Y.; Nakamura, Y.; Tsuji, Y.; Namegaya, Y.; Murata, M.; Woodward, S.

2007-12-01

Two weeks after the 2007 off-Solomon earthquake, an international tsunami survey team (ITST) of Japanese and US researchers performed a post tsunami survey in Ghizo and adjacent islands. Main purpose of the team was to provide information on the earthquake and tsunami to the national disaster council of the Solomon Islands, who was responsible for the disaster management at that time. The ITST had interview with the affected people and conducted reconnaissance mapping of the tsunami heights and flow directions. Tsunami flow heights at beach and inland were evaluated from watermarks on buildings and the position of broken branches and stuck materials on trees. These tsunami heights along the southern to western coasts of Ghizo Island were ca. 5m (a.s.l.). Tsunami run-up was traced by distribution of floating debris that carried up by the tsunami and deposited at their inundation limit. The maximum run-up was measured at Tapurai of Simbo Island to be ca. 9 m. Most of the inundation area was covered by 0-10 cm thick tsunami deposit that consists of beach sand, coral peaces and eroded soil. Coseismic uplift and subsidence were clearly identified by changes of the sea level before and after the earthquake, that were inferred by eyewitness accounts and evidences such as dried up coral reeves. These deformation patterns, as well as the tsunami height distribution, could constrain the earthquake fault geometry and motion. It is worthy of mention that the tsunami damage in villages in Ranongga Island has significantly reduced by 2-3 m uplift before the tsunami attack.

Assessing whether the 2017 Mw 5.4 Pohang earthquake in South Korea was an induced event

NASA Astrophysics Data System (ADS)

Kim, Kwang-Hee; Ree, Jin-Han; Kim, YoungHee; Kim, Sungshil; Kang, Su Young; Seo, Wooseok

2018-06-01

The moment magnitude (Mw) 5.4 Pohang earthquake, the most damaging event in South Korea since instrumental seismic observation began in 1905, occurred beneath the Pohang geothermal power plant in 2017. Geological and geophysical data suggest that the Pohang earthquake was induced by fluid from an enhanced geothermal system (EGS) site, which was injected directly into a near-critically stressed subsurface fault zone. The magnitude of the mainshock makes it the largest known induced earthquake at an EGS site.

Post-earthquake bridge inspection guidelines.

DOT National Transportation Integrated Search

2010-10-01

This report presents a course of action that can be used by New York States Department of Transportation : (NYSDOT) to respond to an earthquake that may have damaged bridges, so that the highway system can be : assessed for safety and functionalit...

Post-earthquake bridge inspection guidelines

DOT National Transportation Integrated Search

2010-10-01

This report presents a course of action that can be used by New York States Department of Transportation : (NYSDOT) to respond to an earthquake that may have damaged bridges, so that the highway system can be : assessed for safety and functionalit...

School Safety Down to Earth: California's Earthquake-Resistant Schools.

ERIC Educational Resources Information Center

Progressive Architecture, 1979

1979-01-01

Schools in California being built to resist damage by earthquakes are part of a program to meet building standards established in 1933. The three new schools presented reflect the strengths and weaknesses of the program. (Author/MLF)

The 2006 Java Earthquake revealed by the broadband seismograph network in Indonesia

NASA Astrophysics Data System (ADS)

Nakano, M.; Kumagai, H.; Miyakawa, K.; Yamashina, T.; Inoue, H.; Ishida, M.; Aoi, S.; Morikawa, N.; Harjadi, P.

2006-12-01

On May 27, 2006, local time, a moderate-size earthquake (Mw=6.4) occurred in central Java. This earthquake caused severe damages near Yogyakarta City, and killed more than 5700 people. To estimate the source mechanism and location of this earthquake, we performed a waveform inversion of the broadband seismograms recorded by a nationwide seismic network in Indonesia (Realtime-JISNET). Realtime-JISNET is a part of the broadband seismograph network developed by an international cooperation among Indonesia, Germany, China, and Japan, aiming at improving the capabilities to monitor seismic activity and tsunami generation in Indonesia. 12 stations in Realitme-JISNET were in operation when the earthquake occurred. We used the three-component seismograms from the two closest stations, which were located about 100 and 300 km from the source. In our analysis, we assumed pure double couple as the source mechanism, thus reducing the number of free parameters in the waveform inversion. Therefore we could stably estimate the source mechanism using the signals observed by a small number of seismic stations. We carried out a grid search with respect to strike, dip, and rake angles to investigate fault orientation and slip direction. We determined source-time functions of the moment-tensor components in the frequency domain for each set of strike, dip, and rake angles. We also conducted a spatial grid search to find the best-fit source location. The best-fit source was approximately 12 km SSE of Yogyakarta at a depth of 10 km below sea level, immediately below the area of extensive damage. The focal mechanism indicates that this earthquake was caused by compressive stress in the NS direction and strike-slip motion was dominant. The moment magnitude (Mw) was 6.4. We estimated the seismic intensity in the areas of severe damage using the source paramters and an empirical attenuation relation for averaged peak ground velocity (PGV) of horizontal seismic motion. We then calculated the instrumental modified Mercalli intensity (Imm) from the estimated PGV values. Our result indicates that strong ground motion with Imm of 7 or more occurred within 10 km of the earthquake fault, although the actual seismic intensity can be affected by shallow structural heterogeneity. We therefore conclude that the severe damages of the Java earthquake are attributed to the strong ground motion, which was primarily caused by the source located immediately below the populated areas.

The Advanced Rapid Imaging and Analysis (ARIA) Project's Response to the April 25, 2015 M7.8 Nepal Earthquake: Rapid Measurements and Models for Science and Situational Awareness

NASA Astrophysics Data System (ADS)

Owen, S. E.; Fielding, E. J.; Yun, S. H.; Yue, H.; Polet, J.; Riel, B. V.; Liang, C.; Huang, M. H.; Webb, F.; Simons, M.; Moore, A. W.; Agram, P. S.; Barnhart, W. D.; Hua, H.; Liu, Z.; Milillo, P.; Sacco, G. F.; Rosen, P. A.; Manipon, G.

2015-12-01

On April 25, 2015, the M7.8 Gorkha earthquake struck Nepal and the city of Kathmandu. The quake caused a significant humanitarian crisis and killed more than 8,000 due to widespread building damage and triggered landslides throughout the region. This was the strongest earthquake to occur in the region since the 1934 Nepal-Bihar magnitude 8.0 quake caused more than 10,000 fatalities. In the days following the earthquake, the JPL/Caltech ARIA project produced coseismic GPS and SAR displacements, fault slip models, and damage assessments from SAR coherence change that were helpful in both understanding the event and in the response efforts. The ARIA project produced InSAR observations from two new SAR missions - JAXA's ALOS-2 and ESA's Sentinel 1a. The GPS coseismic displacements showed ~1.8 meters of southward motion and ~1.3 meters of uplift in Kathmandu. InSAR images of the displacement field and fault models show that the rupture extended 135 km southeast of the epicenter. The SAR imagery also confirmed that the fault slip did not extend to the surface, though localized offsets formed due to liquefaction. The GPS and SAR analysis has continued to image the large M7.3 aftershock and postseismic deformation. The damage assessments from coherence change were used by several organizations guiding the response effort, including the NGA, the World Bank, and OFDA/USAID. We will present imaging, modeling, and damage assessment results from the recent April 25, 2015 M7.8 earthquake in Nepal, and its largest aftershock, a M7.3 event on May 12, 2015. We also discuss how these data were used for understanding the event, guiding the response, and for educational outreach.

Online monitoring of seismic damage in water distribution systems

NASA Astrophysics Data System (ADS)

Liang, Jianwen; Xiao, Di; Zhao, Xinhua; Zhang, Hongwei

2004-07-01

It is shown that water distribution systems can be damaged by earthquakes, and the seismic damages cannot easily be located, especially immediately after the events. Earthquake experiences show that accurate and quick location of seismic damage is critical to emergency response of water distribution systems. This paper develops a methodology to locate seismic damage -- multiple breaks in a water distribution system by monitoring water pressure online at limited positions in the water distribution system. For the purpose of online monitoring, supervisory control and data acquisition (SCADA) technology can well be used. A neural network-based inverse analysis method is constructed for locating the seismic damage based on the variation of water pressure. The neural network is trained by using analytically simulated data from the water distribution system, and validated by using a set of data that have never been used in the training. It is found that the methodology provides an effective and practical way in which seismic damage in a water distribution system can be accurately and quickly located.

Detection of Earthquake-Induced Damage in a Framed Structure Using a Finite Element Model Updating Procedure

PubMed Central

Kim, Seung-Nam; Park, Taewon; Lee, Sang-Hyun

2014-01-01

Damage of a 5-story framed structure was identified from two types of measured data, which are frequency response functions (FRF) and natural frequencies, using a finite element (FE) model updating procedure. In this study, a procedure to determine the appropriate weightings for different groups of observations was proposed. In addition, a modified frame element which included rotational springs was used to construct the FE model for updating to represent concentrated damage at the member ends (a formulation for plastic hinges in framed structures subjected to strong earthquakes). The results of the model updating and subsequent damage detection when the rotational springs (RS model) were used were compared with those obtained using the conventional frame elements (FS model). Comparisons indicated that the RS model gave more accurate results than the FS model. That is, the errors in the natural frequencies of the updated models were smaller, and the identified damage showed clearer distinctions between damaged and undamaged members and was more consistent with observed damage. PMID:24574888

Local-based damage detection of cyclically loaded bridge piers using wireless sensing units

NASA Astrophysics Data System (ADS)

Hou, Tsung-Chin; Lynch, Jerome P.; Parra-Montesinos, Gustavo

2005-05-01

Concrete bridge piers are a common structural element employed in the design of bridges and elevated roadways. In order to ensure adequate behavior under earthquake-induced displacements, extensive reinforcement detailing in the form of closely spaced ties or spirals is necessary, leading to congestion problems and difficulties during concrete casting. Further, costly repairs are often necessary in bridge piers after a major earthquake which in some cases involve the total or partial shutdown of the bridge. In order to increase the damage tolerance while relaxing the transverse reinforcement requirements of bridge piers, the use of high-performance fiber reinforced cementitious composites (HPFRCC) in earthquake-resistant bridge piers is explored. HPFRCCs are a relatively new class of cementitious material for civil structures with tensile strain-hardening behavior and high damage tolerance. To monitor the behavior of this new class of material in the field, low-cost wireless monitoring technologies will be adopted to provide HPFRCC structural elements the capability to accurately monitor their performance and health. In particular, the computational core of a wireless sensing unit can be harnessed to screen HPFRCC components for damage in real-time. A seismic damage index initially proposed for flexure dominated reinforced concrete elements is modified to serve as an algorithmic tool for the rapid assessment of damage (due to flexure and shear) in HPFRCC bridge piers subjected to large shear reversals. Traditional and non-traditional sensor strategies of an HPFRCC bridge pier are proposed to optimize the correlation between the proposed damage index model and the damage observed in a circular pier test specimen. Damage index models are shown to be a sufficiently accurate rough measure of the degree of local-area damage that can then be wirelessly communicated to bridge officials.

Relationships between mental health distress and work-related factors among prefectural public servants two months after the Great East Japan Earthquake.

PubMed

Fukasawa, Maiko; Suzuki, Yuriko; Obara, Akiko; Kim, Yoshiharu

2015-02-01

In times of disaster, public servants face multiple burdens as they engage in a demanding and stressful disaster-response work while managing their own needs caused by the disaster. We investigated the effects of work-related factors on the mental health of prefectural public servants working in the area devastated by the Great East Japan Earthquake to identify some ideas for organizational work modifications to protect their mental health. Two months after the earthquake, Miyagi prefecture conducted a self-administered health survey of prefectural public servants and obtained 4,331 (82.8%) valid responses. We investigated relationships between mental health distress (defined as K6 ≥ 13) and work-related variables (i.e., job type, overwork, and working environment) stratified by level of earthquake damage experienced. The proportion of participants with mental health distress was 3.0% in the group that experienced less damage and 5.9% in the group that experienced severe damage. In the group that experienced less damage, working >100 h of overtime per month (adjusted odds ratio [OR], 2.06; 95% confidence interval [CI], 1.11-3.82) and poor workplace communication (adjusted OR, 10.96; 95% CI, 6.63-18.09) increased the risk of mental health distress. In the group that experienced severe damage, handling residents' complaints (adjusted OR, 4.79; 95% CI, 1.55-14.82) and poor workplace communication (adjusted OR, 9.14; 95% CI, 3.34-24.97) increased the risk, whereas involvement in disaster-related work (adjusted OR, 0.39; 95% CI, 0.18-0.86) decreased the risk. Workers who have experienced less disaster-related damage might benefit from working fewer overtime hours, and those who have experienced severe damage might benefit from avoiding contact with residents and engaging in disaster-related work. Facilitating workplace communication appeared important for both groups of workers.

Effect of harbor modifications on the tsunami vulnerability of Crescent City, California

NASA Astrophysics Data System (ADS)

Dengler, L.; Uslu, B.

2008-12-01

Crescent City, California has experienced more damaging tsunami events in historic times than any other location on the West Coast of the United States. Thirty-one tsunamis have been observed at Crescent City since a tide gauge was established in 1933, including eleven events with maximum peak to trough wave range exceeding one meter and four that caused damage. The most damaging event occurred in 1964 as a result of the great Alaska earthquake. The ensuing tsunami flooded 29 city blocks and killed 11 in the Crescent City area. As a result of the 1964 tsunami and redevelopment projects, the Crescent City harbor was significantly modified in the early 1970s. A 200 x 300 meter small boat basin was carved into the preexisting shore line, a 123 meter dog leg extension was added to the central breakwater and significant deepening occurred on the eastern side of the harbor. In 2006, a Mw 8.3 earthquake in the Kuril Islands generated a moderate Pacific-wide tsunami. The only location with significant damage was the Crescent City harbor where strong currents damaged docks and boats, causing an estimated 9.2 million (US dollars) in damages. Strong currents estimated by the Harbor Master at 12 knots were observed near the entrance to the small boat basin. Past earthquakes from the northwestern Pacific including the 1933 M 8.3 Sanriku Japan earthquake may have produced similar amplitudes at Crescent City to the 2006 event but caused no damage. We have obtained the pre-modification harbor bathymetry and use the MOST model to compare tsunami water heights and current velocities for the 1933 and 2006 sources using modern and pre- modification bathymetry. We also examine model the 1964 inundation using the actual bathymetry and compare the results to numerical simulations that have only used the modern data.

Damage assessment of RC buildings subjected to the different strong motion duration

NASA Astrophysics Data System (ADS)

Mortezaei, Alireza; mohajer Tabrizi, Mohsen

2015-07-01

An earthquake has three important characteristics; namely, amplitude, frequency content and duration. Amplitude and frequency content have a direct impact but not necessarily the sole cause of structural damage. Regarding the duration, some researchers show a high correlation between strong motion duration and structural damage whereas some others find no relation. This paper focuses on the ground motion durations characterized by Arias Intensity (AI). High duration may increase the damage state of structure for the damage accumulation. This paper investigates the response time histories (acceleration, velocity and displacement) of RC buildings under the different strong motion durations. Generally, eight earthquake records were selected from different soil type, and these records were grouped according to their PGA and frequency ranges. Maximum plastic rotation and drift response was chosen as damage indicator. In general, there was a positive correlation between strong motion duration and damage; however, in some PGA and frequency ranges input motions with shorter durations might cause more damage than the input motions with longer durations. In soft soils, input motions with longer durations caused more damage than the input motions with shorter durations.

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 of earthquakes data in northern Red Sea area for different statistics parameters such as correlation, mean, standard deviation, and other. This analysis is to provide a deep understand of the Seismicity of the area, and existing patterns.

Accelerated Seismic Release and Related Aspects of Seismicity Patterns on Earthquake Faults

NASA Astrophysics Data System (ADS)

Ben-Zion, Y.; Lyakhovsky, V.

2001-05-01

Observational studies indicate that large earthquakes are sometimes preceded by phases of accelerated seismic release (ASR) characterized by cumulative Benioff strain following a power law time-to-failure relation with a term (tf - t)m, where tf is the failure time of the large event and observed values of m are close to 0.3. We discuss properties of ASR and related aspects of seismicity patterns associated with several theoretical frameworks, with a focus on models of heterogeneous faults in continuum solids. Using stress and earthquake histories simulated by the model of Ben-Zion (1996) for a discrete fault with quenched heterogeneities in a 3D elastic half space, we show that large model earthquakes are associated with non-repeating cyclical establishment and destruction of long-range stress correlations, accompanied by non-stationary cumulative Benioff strain release. We then analyze results associated with a regional lithospheric model consisting of a seismogenic upper crust governed by the damage rheology of Lyakhovsky et al. (1997) over a viscoelastic substrate. We demonstrate analytically for a simplified 1D case that the employed damage rheology leads to a singular power law equation for strain proportional to (tf - t)-1/3, and a non-singular power law relation for cumulative Benioff strain proportional to (tf - t)1/3. A simple approximate generalization of the latter for regional cumulative Benioff strain is obtained by adding to the result a linear function of time representing a stationary background release. To go beyond the analytical expectations, we examine results generated by various realizations of the regional lithospheric model producing seismicity following the characteristic frequency-size statistics, Gutenberg-Richter power law distribution, and mode switching activity. We find that phases of ASR exist only when the seismicity preceding a given large event has broad frequency-size statistics. In such cases the simulated ASR phases can be fitted well by the singular analytical relation with m = -1/3, the non-singular equation with m = 0.2, and the generalized version of the latter including a linear term with m = 1/3. The obtained good fits with all three relations highlight the difficulty of deriving reliable information on functional forms and parameter values from such data sets. The activation process in the simulated ASR phases is found to be accommodated both by increasing rates of moderate events and increasing average event size, with the former starting a few years earlier than the latter. The lack of ASR in portions of the seismicity not having broad frequency-size statistics may explain why some large earthquakes are preceded by ASR and other are not.

Oklahoma Area Struck By Magnitude 5.0 Earthquake Imaged by NASA Satellite

NASA Image and Video Library

2016-11-08

On Sunday, Nov. 6, 2016, at 7:44 p.m. local time, a magnitude 5.0 earthquake struck near the town of Cushing, Oklahoma. Numerous buildings were damaged by the temblor, but only a few minor injuries were reported. Cushing is home to one of the world's largest oil storage terminals; no damage was reported to the petroleum facilities. A star marks the epicenter of the earthquake,which occurred at a depth of 3.1 miles (5 kilometers). The image was acquired April 28, 2011, covers an area of 7 by 9 miles (11.4 by 14.5 kilometers), and is located at 36 degrees north, 96.8 degrees west. http://photojournal.jpl.nasa.gov/catalog/PIA21099

Scientific drilling into the San Andreas Fault Zone

USGS Publications Warehouse

Zoback, Mark; Hickman, Stephen; Ellsworth, William

2010-01-01

This year, the world has faced energetic and destructive earthquakes almost every month. In January, an M = 7.0 event rocked Haiti, killing an estimated 230,000 people. In February, an M = 8.8 earthquake and tsunami claimed over 500 lives and caused billions of dollars of damage in Chile. Fatal earthquakes also occurred in Turkey in March and in China and Mexico in April.

Shock Absorbers Save Structures and Lives during Earthquakes

NASA Technical Reports Server (NTRS)

2015-01-01

With NASA funding, North Tonawanda, New York-based Taylor Devices Inc. developed fluidic shock absorbers to safely remove the fuel and electrical connectors from the space shuttles during launch. The company is now employing the technology as seismic dampers to protect structures from earthquakes. To date, 550 buildings and bridges have the dampers, and not a single one has suffered damage in the wake of an earthquake.

The 2006 Pingtung Earthquake Doublet Triggered Seafloor Liquefaction: Revisiting the Evidence with Ultra-High-Resolution Seafloor Mapping

NASA Astrophysics Data System (ADS)

Su, C. C.; Chen, T. T.; Paull, C. K.; Gwiazda, R.; Chen, Y. H.; Lundsten, E. M.; Caress, D. W.; Hsu, H. H.; Liu, C. S.

2017-12-01

Since Heezen and Ewing's (1952) classic work on the 1929 Grand Banks earthquake, the damage of submarine cables have provided critical information on the nature of seafloor mass movements or sediment density flows. However, the understanding of the local conditions that lead to particular seafloor failures earthquakes trigger is still unclear. The Decemeber 26, 2006 Pingtung earthquake doublet which occurred offshore of Fangliao Township, southwestern Taiwan damaged 14 submarine cables between Gaoping slope to the northern terminus of the Manila Trench. Local fisherman reported disturbed waters at the head of the Fangliao submarine canyon, which lead to conjectures that eruptions of mud volcanoes which are common off the southwestern Taiwan. Geophysical survey were conducted to evaluate this area which revealed a series of faults, liquefied strata, pockmarks and acoustically transparent sediments with doming structures which may relate to the submarine groundwater discharge. Moreover, shipboard multi-beam bathymetric survey which was conducted at the east of Fangliao submarine canyon head shows over 10 km2 area with maximum depth around 40 m of seafloor subsidence after Pingtung earthquake. The north end of the subsidence is connected to the Fangliao submarine canyon where the first cable failed after Pingtung earthquake. The evidences suggests the earthquake triggered widespeard liquefaction and generated debris flows within Fangliao submarine canyon. In May 2017, an IONTU-MBARI Joint Survey Cruise (OR1-1163) was conducted on using MBARI Mapping AUV and miniROV to revisit the area where the cable damaged after Pingtung earthquake. From newly collected ultra-high-resolution (1-m lateral resolution) bathymetry data, the stair-stepped morphology is observed at the edge of canyon. The comet-shaped depressions are located along the main headwall of the seafloor failure. The new detailed bathymetry reveal details which suggest Fangliao submarine canyon head is preconditioned to failure. Submarine groundwater discharge from the Pingtung Plain and the southern tip of the Central Mountains is inferred to generate elevated pore pressures leaving the area susceptible to liquefaction and failure when triggered by earthquakes.

The effect of segmented fault zones on earthquake rupture propagation and termination

NASA Astrophysics Data System (ADS)

Huang, Y.

2017-12-01

A fundamental question in earthquake source physics is what can control the nucleation and termination of an earthquake rupture. Besides stress heterogeneities and variations in frictional properties, damaged fault zones (DFZs) that surround major strike-slip faults can contribute significantly to earthquake rupture propagation. Previous earthquake rupture simulations usually characterize DFZs as several-hundred-meter-wide layers with lower seismic velocities than host rocks, and find earthquake ruptures in DFZs can exhibit slip pulses and oscillating rupture speeds that ultimately enhance high-frequency ground motions. However, real DFZs are more complex than the uniform low-velocity structures, and show along-strike variations of damages that may be correlated with historical earthquake ruptures. These segmented structures can either prohibit or assist rupture propagation and significantly affect the final sizes of earthquakes. For example, recent dense array data recorded at the San Jacinto fault zone suggests the existence of three prominent DFZs across the Anza seismic gap and the south section of the Clark branch, while no prominent DFZs were identified near the ends of the Anza seismic gap. To better understand earthquake rupture in segmented fault zones, we will present dynamic rupture simulations that calculate the time-varying rupture process physically by considering the interactions between fault stresses, fault frictional properties, and material heterogeneities. We will show that whether an earthquake rupture can break through the intact rock outside the DFZ depend on the nucleation size of the earthquake and the rupture propagation distance in the DFZ. Moreover, material properties of the DFZ, stress conditions along the fault, and friction properties of the fault also have a critical impact on rupture propagation and termination. We will also present scenarios of San Jacinto earthquake ruptures and show the parameter space that is favorable for rupture propagation through the Anza seismic gap. Our results suggest that a priori knowledge of properties of segmented fault zones is of great importance for predicting sizes of future large earthquakes on major faults.

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

NASA Astrophysics Data System (ADS)

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

2017-04-01

Recently our understanding of tectonic faulting has been shaken by the discoveries of seismic tremor, low frequency earthquakes, slow slip events, and other models of fault slip. These phenomenas represent models of failure that were thought to be non-existent and theoretically impossible only a few years ago. Slow earthquakes are seismic phenomena in which the rupture of geological faults in the earth's crust occurs gradually without creating strong tremors. Despite the growing number of observations of slow earthquakes their origin remains unresolved. Studies show that the duration of slow earthquakes ranges from a few seconds to a few hundred seconds. The regular earthquakes with which most people are familiar release a burst of built-up stress in seconds, slow earthquakes release energy in ways that do little damage. This study focus on the characteristics of the Mw5.6 earthquake occurred in Sofia seismic zone on May 22nd, 2012. The Sofia area is the most populated, industrial and cultural region of Bulgaria that faces considerable earthquake risk. The Sofia seismic zone is located in South-western Bulgaria - the area with pronounce tectonic activity and proved crustal movement. In 19th century the city of Sofia (situated in the centre of the Sofia seismic zone) has experienced two strong earthquakes with epicentral intensity of 10 MSK. During the 20th century the strongest event occurred in the vicinity of the city of Sofia is the 1917 earthquake with MS=5.3 (I0=7-8 MSK64).The 2012 quake occurs in an area characterized by a long quiescence (of 95 years) for moderate events. Moreover, a reduced number of small earthquakes have also been registered in the recent past. The Mw5.6 earthquake is largely felt on the territory of Bulgaria and neighbouring countries. No casualties and severe injuries have been reported. Mostly moderate damages were observed in the cities of Pernik and Sofia and their surroundings. These observations could be assumed indicative for a very low rupture velocity. The low rupture velocity can mean slow-faulting, which brings to slow release of accumulated seismic energy. The slow release energy does principally little to moderate damages. Additionally wave form of the earthquake shows low frequency content of P-waves (the maximum P-wave is at 1.19 Hz) and the specific P- wave displacement spectral is characterise with not expressed spectrum plateau and corner frequency. These and other signs suggest us to the conclusion, that the 2012 Mw5.6 earthquake can be considered as types of slow earthquake, like a low frequency quake. The study is based on data from Bulgarian seismological network (NOTSSI), the local network (LSN) deployed around Kozloduy NPP and System of Accelerographs for Seismic Monitoring of Equipment and Structures (SASMES) installed in the Kozloduy NPP. NOTSSI jointly with LSN and SASMES provide reliable information for multiple studies on seismicity in regional scale.

Constraints on Fault Damage Zone Properties and Normal Modes from a Dense Linear Array Deployment along the San Jacinto Fault Zone

NASA Astrophysics Data System (ADS)

Allam, A. A.; Lin, F. C.; Share, P. E.; Ben-Zion, Y.; Vernon, F.; Schuster, G. T.; Karplus, M. S.

2016-12-01

We present earthquake data and statistical analyses from a month-long deployment of a linear array of 134 Fairfield three-component 5 Hz seismometers along the Clark strand of the San Jacinto fault zone in Southern California. With a total aperture of 2.4km and mean station spacing of 20m, the array locally spans the entire fault zone from the most intensely fractured core to relatively undamaged host rock on the outer edges. We recorded 36 days of continuous seismic data at 1000Hz sampling rate, capturing waveforms from 751 local events with Mw>0.5 and 43 teleseismic events with M>5.5, including two 600km deep M7.5 events along the Andean subduction zone. For any single local event on the San Jacinto fault, the central stations of the array recorded both higher amplitude and longer duration waveforms, which we interpret as the result of damage-related low-velocity structure acting as a broad waveguide. Using 271 San Jacinto events, we compute the distributions of three quantities for each station: maximum amplitude, mean amplitude, and total energy (the integral of the envelope). All three values become statistically lower with increasing distance from the fault, but in addition show a nonrandom zigzag pattern which we interpret as normal mode oscillations. This interpretation is supported by polarization analysis which demonstrates that the high-amplitude late-arriving energy is strongly vertically polarized in the central part of the array, consistent with Love-type trapped waves. These results, comprising nearly 30,000 separate coseismic waveforms, support the consistent interpretation of a 450m wide asymmetric damage zone, with the lowest velocities offset to the northeast of the mapped surface trace by 100m. This asymmetric damage zone has important implications for the earthquake dynamics of the San Jacinto and especially its ability to generate damaging multi-segment ruptures.

Post-Disaster Damage Assessment Through Coherent Change Detection on SAR Imagery

NASA Astrophysics Data System (ADS)

Guida, L.; Boccardo, P.; Donevski, I.; Lo Schiavo, L.; Molinari, M. E.; Monti-Guarnieri, A.; Oxoli, D.; Brovelli, M. A.

2018-04-01

Damage assessment is a fundamental step to support emergency response and recovery activities in a post-earthquake scenario. In recent years, UAVs and satellite optical imagery was applied to assess major structural damages before technicians could reach the areas affected by the earthquake. However, bad weather conditions may harm the quality of these optical assessments, thus limiting the practical applicability of these techniques. In this paper, the application of Synthetic Aperture Radar (SAR) imagery is investigated and a novel approach to SAR-based damage assessment is presented. Coherent Change Detection (CCD) algorithms on multiple interferometrically pre-processed SAR images of the area affected by the seismic event are exploited to automatically detect potential damages to buildings and other physical structures. As a case study, the 2016 Central Italy earthquake involving the cities of Amatrice and Accumoli was selected. The main contribution of the research outlined above is the integration of a complex process, requiring the coordination of a variety of methods and tools, into a unitary framework, which allows end-to-end application of the approach from SAR data pre-processing to result visualization in a Geographic Information System (GIS). A prototype of this pipeline was implemented, and the outcomes of this methodology were validated through an extended comparison with traditional damage assessment maps, created through photo-interpretation of high resolution aerial imagery. The results indicate that the proposed methodology is able to perform damage detection with a good level of accuracy, as most of the detected points of change are concentrated around highly damaged buildings.

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. 

Damage and Site Effects of the May 2012 Emilia-Romagna and Lombardia Earthquake, with Particular Reference to the "Oltrepò Mantovano" (Mantua) Territory

NASA Astrophysics Data System (ADS)

Daminelli, R.; Marcellini, A.; Tento, A.

2014-12-01

The seismic sequence that struck the Lombardia and Emilia-Romagna in May 2012 consisted of seven main events of magnitude greater than 5 followed by numerous aftershocks. The strongest earthquakes occurred on May 20 (M=5.9) and May 29 (M=5.8) near the border between Lombardia and Emilia-Romagna. The epicenters of the main events are aligned in east-west direction in a segment of approx. 50 km just south of the Po river. The area was considered a low to medium seismicity: the seismic hazard in the epicentral area, and in the whole damaged area, was estimated to be less than 0.15 g PGA for 10% exceedance in 50 years. Significant damage occurred over an area greater than 1000 km2, which is extremely large for earthquakes of magnitude less than 6, bearing in mind the low vulnerability level of the structures. As seen in detailed geological investigations the degree of damage and its areal extent is largely attributable to the particular conditions of the soil. We focus on the relationship between damage and soil conditions in the area of Oltrepò Mantovano, situated between the Po River and the epicentral area. The soil is largely composed of Quaternary deposits of sands, silty-clay and clay with a very deep bedrock (greater than 100 m) and Vs30 generally less than 500 m/s. According to the cards Aedes (official forms of the Italian Government to assess the state of damage of buildings) houses declared uninhabitable because of the earthquake were mainly concentrated in a few small towns: Moglia, Gonzaga, Quistello and San Giacomo delle Segnate (located approximately at 20 km, 27 km, 20 km and 14 km from the epicenters of the two main shocks, respectively) which reported 73% of the total of all uninhabitable buildings; Moglia 27 %, Gonzaga 14%, Quistello 20% and San Giacomo delle Segnate 12%. The hydrographic system has evolved considerably since the Middle Bronze Age with the result that the area is characterized by a complex geomorphology with the presence of fluvial paleochannels, fluvial ridges and abandoned river channels where numerous cases of soil liquefaction have been observed. The May 2012 earthquake has highlighted a close relationship between the sites where the damage was concentrated and the geological and geomorphological characteristics of the area.

Localized surface disruptions observed by InSAR during strong earthquakes in Java and Hawai'i

USGS Publications Warehouse

Poland, M.

2010-01-01

Interferometric Synthetic Aperture Radar data spanning strong earthquakes on the islands of Java and Hawai‘i in 2006 reveal patches of subsidence and incoherence indicative of localized ground failure. Interferograms spanning the 26 May 2006 Java earthquake suggest an area of about 7.5 km2 of subsidence (~2 cm) and incoherence south of the city of Yogyakarta that correlates with significant damage to housing, high modeled peak ground accelerations, and poorly consolidated geologic deposits. The subsidence and incoherence is inferred to be a result of intense shaking and/or damage. At least five subsidence patches on the west side of the Island of Hawai‘i, ranging 0.3–2.2 km2 in area and 3–8 cm in magnitude, occurred as a result of a pair of strong earthquakes on 15 October 2006. Although no felt reports or seismic data are available from the areas in Hawai‘i, the Java example suggests that the subsidence patches indicate areas of amplified earthquake shaking. Surprisingly, all subsidence areas in Hawai‘i were limited to recent, and supposedly stable, lava flows and may reflect geological conditions not detectable at the surface. In addition, two ‘a‘ā lava flows in Hawai‘i were partially incoherent in interferograms spanning the earthquakes, indicating surface disruption as a result of the earthquake shaking. Coearthquake incoherence of rubbly deposits, like ‘a‘ā flows, should be explored as a potential indicator of earthquake intensity and past strong seismic activity.

Preliminary observations from the 3 January 2017, MW 5.6 Manu, Tripura (India) earthquake

NASA Astrophysics Data System (ADS)

Debbarma, Jimmi; Martin, Stacey S.; Suresh, G.; Ahsan, Aktarul; Gahalaut, Vineet K.

2017-10-01

On 3 January 2017, a MW 5.6 earthquake occurred in Dhalai district in Tripura (India), at 14:39:03 IST (09:09:03 UTC) with an epicentre at 24.018°N ± 4.9 km and 91.964°E ± 4.4 km, and a focal depth of 31 ± 6.0 km. The focal mechanism solution determined after evaluating data from seismological observatories in India indicated a predominantly strike-slip motion on a steeply dipping plane. The estimated focal depth and focal mechanism solution places this earthquake in the Indian plate that lies beneath the overlying Indo-Burmese wedge. As in the 2016 Manipur earthquake, a strong motion record from Shillong, India, appears to suggest site amplification possibly due to topographic effects. In the epicentral region in Tripura, damage assessed from a field survey and from media reports indicated that the macroseismic intensity approached 6-7 EMS with damage also reported in adjacent parts of Bangladesh. A striking feature of this earthquake were the numerous reports of liquefaction that were forthcoming from fluvial locales in the epicentral region in Tripura, and at anomalous distances farther north in Bangladesh. The occurrence of the 2017 Manu earthquake emphasises the hazard posed by intraplate earthquakes in Tripura and in the neighbouring Bengal basin region where records of past earthquakes are scanty or vague, and where the presence of unconsolidated deltaic sediments and poor implementation of building codes pose a significant societal and economic threat during larger earthquakes in the future.

The effect of yield strength and ductility to fatigue damage

NASA Technical Reports Server (NTRS)

Yeh, H. Y.

1973-01-01

The cumulative damage of aluminium alloys with different yield strength and various ductility due to seismic loads was studied. The responses of an idealized beam with a centered mass at one end and fixed at the other end to El Centro's and Taft's earthquakes are computed by assuming that the alloys are perfectly elastoplastic materials and by using numerical technique. Consequently, the corresponding residual plastic strain can be obtained from the stress-strain relationship. The revised Palmgren-Miner cumulative damage theorem is utilized to calculate the fatigue damage. The numerical results show that in certain cases, the high ductility materials are more resistant to seismic loads than the high yield strength materials. The results also show that if a structure collapse during the earthquake, the collapse always occurs in the very early stage.

Soil quality as a factor of the distribution of damages at the meizoseismal area of the Kozani-Grevena 1995 earthquake, in Greece ( Ms = 6.6)

NASA Astrophysics Data System (ADS)

Christaras, B.; Dimitriou, An; Lemoni, Hel

The physical and mechanical properties of the soil formations were related to the damages observed in Kozani and Grevena area, in Northern Greece, after the earth-quake of 13th May 1995 ( Ms = 6.6). Properties such as grain size distribution, plasticity, shear strength, compression index, permeability and ultrasonic velocity were measured in order to classify the suitability of the soil formations, for urban planning, and correlate their mechanical behaviour with the damages observed in the construction. According to our observations, a great number of recent buildings were damaged also in areas far away from the seismotectonic zones, where silty and clayey soils dominate, presenting very low permeability, low ultrasonic velocity together with high plasticity and compressibility.

Automatic Building Damage Detection Method Using High-Resolution Remote Sensing Images and 3d GIS Model

NASA Astrophysics Data System (ADS)

Tu, Jihui; Sui, Haigang; Feng, Wenqing; Song, Zhina

2016-06-01

In this paper, a novel approach of building damaged detection is proposed using high resolution remote sensing images and 3D GIS-Model data. Traditional building damage detection method considers to detect damaged building due to earthquake, but little attention has been paid to analyze various building damaged types(e.g., trivial damaged, severely damaged and totally collapsed.) Therefore, we want to detect the different building damaged type using 2D and 3D feature of scenes because the real world we live in is a 3D space. The proposed method generalizes that the image geometric correction method firstly corrects the post-disasters remote sensing image using the 3D GIS model or RPC parameters, then detects the different building damaged types using the change of the height and area between the pre- and post-disasters and the texture feature of post-disasters. The results, evaluated on a selected study site of the Beichuan earthquake ruins, Sichuan, show that this method is feasible and effective in building damage detection. It has also shown that the proposed method is easily applicable and well suited for rapid damage assessment after natural disasters.

Understanding continental megathrust earthquake potential through geological mountain building processes: an example in Nepal Himalaya

NASA Astrophysics Data System (ADS)

Zhang, Huai; Zhang, Zhen; Wang, Liangshu; Leroy, Yves; shi, Yaolin

2017-04-01

How to reconcile continent megathrust earthquake characteristics, for instances, mapping the large-great earthquake sequences into geological mountain building process, as well as partitioning the seismic-aseismic slips, is fundamental and unclear. Here, we scope these issues by focusing a typical continental collisional belt, the great Nepal Himalaya. We first prove that refined Nepal Himalaya thrusting sequences, with accurately defining of large earthquake cycle scale, provide new geodynamical hints on long-term earthquake potential in association with, either seismic-aseismic slip partition up to the interpretation of the binary interseismic coupling pattern on the Main Himalayan Thrust (MHT), or the large-great earthquake classification via seismic cycle patterns on MHT. Subsequently, sequential limit analysis is adopted to retrieve the detailed thrusting sequences of Nepal Himalaya mountain wedge. Our model results exhibit apparent thrusting concentration phenomenon with four thrusting clusters, entitled as thrusting 'families', to facilitate the development of sub-structural regions respectively. Within the hinterland thrusting family, the total aseismic shortening and the corresponding spatio-temporal release pattern are revealed by mapping projection. Whereas, in the other three families, mapping projection delivers long-term large (M<8)-great (M>8) earthquake recurrence information, including total lifespans, frequencies and large-great earthquake alternation information by identifying rupture distances along the MHT. In addition, this partition has universality in continental-continental collisional orogenic belt with identified interseismic coupling pattern, while not applicable in continental-oceanic megathrust context.

Damage extraction of buildings in the 2015 Gorkha, Nepal earthquake from high-resolution SAR data

NASA Astrophysics Data System (ADS)

Yamazaki, Fumio; Bahri, Rendy; Liu, Wen; Sasagawa, Tadashi

2016-05-01

Satellite remote sensing is recognized as one of the effective tools for detecting and monitoring affected areas due to natural disasters. Since SAR sensors can capture images not only at daytime but also at nighttime and under cloud-cover conditions, they are especially useful at an emergency response period. In this study, multi-temporal high-resolution TerraSAR-X images were used for damage inspection of the Kathmandu area, which was severely affected by the April 25, 2015 Gorkha Earthquake. The SAR images obtained before and after the earthquake were utilized for calculating the difference and correlation coefficient of backscatter. The affected areas were identified by high values of the absolute difference and low values of the correlation coefficient. The post-event high-resolution optical satellite images were employed as ground truth data to verify our results. Although it was difficult to estimate the damage levels for individual buildings, the high resolution SAR images could illustrate their capability in detecting collapsed buildings at emergency response times.

Recorded motions of the 6 April 2009 Mw 6.3 L'Aquila, Italy, earthquake and implications for building structural damage: Overview

USGS Publications Warehouse

Celebi, M.; Bazzurro, P.; Chiaraluce, L.; Clemente, P.; Decanini, L.; Desortis, A.; Ellsworth, W.; Gorini, A.; Kalkan, E.; Marcucci, S.; Milana, G.; Mollaioli, F.; Olivieri, M.; Paolucci, R.; Rinaldis, D.; Rovelli, A.; Sabetta, F.; Stephens, C.

2010-01-01

The normal-faulting earthquake of 6 April 2009 in the Abruzzo Region of central Italy caused heavy losses of life and substantial damage to centuriesold buildings of significant cultural importance and to modern reinforcedconcrete- framed buildings with hollow masonry infill walls. Although structural deficiencies were significant and widespread, the study of the characteristics of strong motion data from the heavily affected area indicated that the short duration of strong shaking may have spared many more damaged buildings from collapsing. It is recognized that, with this caveat of shortduration shaking, the infill walls may have played a very important role in preventing further deterioration or collapse of many buildings. It is concluded that better new or retrofit construction practices that include reinforcedconcrete shear walls may prove helpful in reducing risks in such seismic areas of Italy, other Mediterranean countries, and even in United States, where there are large inventories of deficient structures. ?? 2010, Earthquake Engineering Research Institute.

Amplification of earthquake ground motions in Washington, DC, and implications for hazard assessments in central and eastern North America

USGS Publications Warehouse

Pratt, Thomas L.; Horton, J. Wright; Munoz, Jessica; Hough, Susan E.; Chapman, Martin C.; Olgun, C. Guney

2017-01-01

The extent of damage in Washington, DC, from the 2011 Mw 5.8 Mineral, VA, earthquake was surprising for an epicenter 130 km away; U.S. Geological Survey “Did-You-Feel-It” reports suggest that Atlantic Coastal Plain and other unconsolidated sediments amplified ground motions in the city. We measure this amplification relative to bedrock sites using earthquake signals recorded on a temporary seismometer array. The spectral ratios show strong amplification in the 0.7 to 4 Hz frequency range for sites on sediments. This range overlaps with resonant frequencies of buildings in the city as inferred from their heights, suggesting amplification at frequencies to which many buildings are vulnerable to damage. Our results emphasize that local amplification can raise moderate ground motions to damaging levels in stable continental regions, where low attenuation extends shaking levels over wide areas and unconsolidated deposits on crystalline metamorphic or igneous bedrock can result in strong contrasts in near-surface material properties.

Earth Observations taken by the Expedition 10 crew

NASA Image and Video Library

2005-01-14

ISS010-E-13088 (15 January 2005) --- Tsunami damage, northwestern Sumatra (Indonesia) is featured in this image photographed by an Expedition 10 crewmember on the International Space Station. On December 26, 2004 a large (magnitude 9.0) earthquake occurred off the western coast of Sumatra in the Indian Ocean. Scientists believe the earthquake was caused by the release of stresses accumulated as the India tectonic plate is overridden by the Burma tectonic plate. Movement of the seafloor due to the earthquake generated a tsunami, or seismic sea wave, that affected coastal regions around the Indian Ocean. The northwestern Sumatra coastline in particular suffered extensive damage and loss of life. This photo, along with image ISS010-E-13079, illustrates damage along the southwestern coast of Aceh Province in the vicinity of the city of Lho’ Kruet, Indonesia. The image captures the sunglint illuminating the Indian Ocean and standing water inland (light gray). Distortion and scale differences are caused by increased obliquity of the view from the Station.

Earth Observations taken by the Expedition 10 crew

NASA Image and Video Library

2005-01-14

ISS010-E-13079 (15 January 2005) --- Tsunami damage, northwestern Sumatra (Indonesia) is featured in this image photographed by an Expedition 10 crewmember on the International Space Station (ISS). On December 26, 2004 a large (magnitude 9.0) earthquake occurred off the western coast of Sumatra in the Indian Ocean. Scientists believe the earthquake was caused by the release of stresses accumulated as the India tectonic plate is overridden by the Burma tectonic plate. Movement of the seafloor due to the earthquake generated a tsunami, or seismic sea wave, that affected coastal regions around the Indian Ocean. The northwestern Sumatra coastline in particular suffered extensive damage and loss of life. This photo, along with image ISS010-E-13088, illustrates damage along the southwestern coast of Aceh Province in the vicinity of the city of Lho’ Kruet, Indonesia. Large areas of bare and disturbed soil (brownish gray) previously covered with vegetation are visible along the coastline. Embayments in the coastline were particularly hard hit, while adjacent headlands were less affected.

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.

POST Earthquake Debris Management — AN Overview

NASA Astrophysics Data System (ADS)

Sarkar, Raju

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

POST Earthquake Debris Management - AN Overview

NASA Astrophysics Data System (ADS)

Sarkar, Raju

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