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Sample records for earthquake caused significant

  1. Earthquakes

    MedlinePlus

    ... Search Term(s): Main Content Home Be Informed Earthquakes Earthquakes An earthquake is the sudden, rapid shaking of the earth, ... by the breaking and shifting of underground rock. Earthquakes can cause buildings to collapse and cause heavy ...

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

    NASA Astrophysics Data System (ADS)

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

    2017-12-01

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

  3. Catalog of significant historical earthquakes in the Central United States

    USGS Publications Warehouse

    Bakun, W.H.; Hopper, M.G.

    2004-01-01

    We use Modified Mercalli intensity assignments to estimate source locations and moment magnitude M for eighteen 19th-century and twenty early- 20th-century earthquakes in the central United States (CUS) for which estimates of M are otherwise not available. We use these estimates, and locations and M estimated elsewhere, to compile a catelog of significant historical earthquakes in the CUS. The 1811-1812 New Madrid earthquakes apparently dominated CUS seismicity in the first two decades of the 19th century. M5-6 earthquakes occurred in the New Madrid Seismic Zone in 1843 and 1878, but none have occurred since 1878. There has been persistent seismic activity in the Illinois Basin in southern Illinois and Indiana, with M > 5.0 earthquakes in 1895, 1909, 1917, 1968, and 1987. Four other M > 5.0 CUS historical earthquakes have occurred: in Kansas in 1867, in Nebraska in 1877, in Oklahoma in 1882, and in Kentucky in 1980.

  4. Earthquakes

    MedlinePlus

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

  5. Preparing for a significant central U.S. earthquake : science needs of the emergency response community.

    DOT National Transportation Integrated Search

    2009-02-01

    The New Madrid and Wabash Valley seismic zones are capable of producing large magnitude earthquakes that could cause significant damage and interrupt the east to west flow of transportation, communication, electricity, natural gas and oil across the ...

  6. Earthquakes.

    ERIC Educational Resources Information Center

    Walter, Edward J.

    1977-01-01

    Presents an analysis of the causes of earthquakes. Topics discussed include (1) geological and seismological factors that determine the effect of a particular earthquake on a given structure; (2) description of some large earthquakes such as the San Francisco quake; and (3) prediction of earthquakes. (HM)

  7. History of significant earthquakes in the Parkfield area

    USGS Publications Warehouse

    Bakun, W.H.

    1988-01-01

    Seismicity on the San Andreas fault near Parkfield occurs in a tectonic section that differs markedly from neighboring sections along the San Andreas to the northwest and to the southeast. Northwest of the Parkfield section, small shocks (magnitudes of less than 4) do occur frequently, but San Andreas movement occurs predominantly as aseismic fault creep; shocks of magnitude 6 and larger are unknown, and little, if any, strain is accumulating. In contrast, very few small earthquakes and no aseismic slip have been observed on the adjacent section to the southeast, the Cholame section, which is considered to be locked, in as much as it apparently ruptures exclusively in large earthquakes (magnitudes greater than 7), most recently during the great Fort Tejon earthquake of 1857. The Parkfield section is thus a transition zone between two sections having different modes of fault failure. In fact, the regularity of significant earthquakes at Parkfield since 1857 may be due to the nearly constant slip rate pattern on the adjoining fault sections. Until the magnitude 6.7 Coalinga earthquake on May 2, 1983, 40 kilmoeters northeast of Parkfield, the Parkfield section had been relatively free of stress changes due to nearby shocks; the effect of the Coalinga shock on the timing of the next Parkfield shock is not known. 

  8. Challenges to communicate risks of human-caused earthquakes

    NASA Astrophysics Data System (ADS)

    Klose, C. D.

    2014-12-01

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

  9. Statistical aspects and risks of human-caused earthquakes

    NASA Astrophysics Data System (ADS)

    Klose, C. D.

    2013-12-01

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

  10. Understanding earthquake from the granular physics point of view — Causes of earthquake, earthquake precursors and predictions

    NASA Astrophysics Data System (ADS)

    Lu, Kunquan; Hou, Meiying; Jiang, Zehui; Wang, Qiang; Sun, Gang; Liu, Jixing

    2018-03-01

    We treat the earth crust and mantle as large scale discrete matters based on the principles of granular physics and existing experimental observations. Main outcomes are: A granular model of the structure and movement of the earth crust and mantle is established. The formation mechanism of the tectonic forces, which causes the earthquake, and a model of propagation for precursory information are proposed. Properties of the seismic precursory information and its relevance with the earthquake occurrence are illustrated, and principle of ways to detect the effective seismic precursor is elaborated. The mechanism of deep-focus earthquake is also explained by the jamming-unjamming transition of the granular flow. Some earthquake phenomena which were previously difficult to understand are explained, and the predictability of the earthquake is discussed. Due to the discrete nature of the earth crust and mantle, the continuum theory no longer applies during the quasi-static seismological process. In this paper, based on the principles of granular physics, we study the causes of earthquakes, earthquake precursors and predictions, and a new understanding, different from the traditional seismological viewpoint, is obtained.

  11. Significance of beating observed in earthquake responses of buildings

    USGS Publications Warehouse

    Çelebi, Mehmet; Ghahari, S. F.; Taciroglu, E.

    2016-01-01

    The beating phenomenon observed in the recorded responses of a tall building in Japan and another in the U.S. are examined in this paper. Beating is a periodic vibrational behavior caused by distinctive coupling between translational and torsional modes that typically have close frequencies. Beating is prominent in the prolonged resonant responses of lightly damped structures. Resonances caused by site effects also contribute to accentuating the beating effect. Spectral analyses and system identification techniques are used herein to quantify the periods and amplitudes of the beating effects from the strong motion recordings of the two buildings. Quantification of beating effects is a first step towards determining remedial actions to improve resilient building performance to strong earthquake induced shaking.

  12. Distribution of scientific raw data of human-caused earthquakes

    NASA Astrophysics Data System (ADS)

    Klose, C. D.

    2012-12-01

    The second catalog edition on earthquakes caused by humans is presented that was recently published in the Journal of Seismology. The earthquakes with seismic magnitudes of up to M=7.9 have been documented and published since the first half of the 20th century. They were caused by geomechanical pollution due to artificial water reservoir impoundments, underground and open-pit mining, coastal management, hydrocarbon production and fluid injections/extractions. The overall data set contains physical properties that were collected and initially summarized in an unpublished earthquake catalog presented at a meeting of Seismological Society of America in 2006. The earthquakes result from a larger set of more than 500 scientific research papers, conference proceedings and abstracts. The overall data set is made available for the public at www.cdklose.com, which includes actual properties and features, figures that explain physical relationships, and statistical correlation and regression tests. The data set can be used by students, educators, the general public or scientists from other disciplines who are interested in the environmental hazard of human-caused earthquakes.

  13. Significance of stress transfer in time-dependent earthquake probability calculations

    USGS Publications Warehouse

    Parsons, T.

    2005-01-01

    A sudden change in stress is seen to modify earthquake rates, but should it also revise earthquake probability? Data used to derive input parameters permits an array of forecasts; so how large a static stress change is require to cause a statistically significant earthquake probability change? To answer that question, effects of parameter and philosophical choices are examined through all phases of sample calculations, Drawing at random from distributions of recurrence-aperiodicity pairs identifies many that recreate long paleoseismic and historic earthquake catalogs. Probability density funtions built from the recurrence-aperiodicity pairs give the range of possible earthquake forecasts under a point process renewal model. Consequences of choices made in stress transfer calculations, such as different slip models, fault rake, dip, and friction are, tracked. For interactions among large faults, calculated peak stress changes may be localized, with most of the receiving fault area changed less than the mean. Thus, to avoid overstating probability change on segments, stress change values should be drawn from a distribution reflecting the spatial pattern rather than using the segment mean. Disparity resulting from interaction probability methodology is also examined. For a fault with a well-understood earthquake history, a minimum stress change to stressing rate ratio of 10:1 to 20:1 is required to significantly skew probabilities with >80-85% confidence. That ratio must be closer to 50:1 to exceed 90-95% confidence levels. Thus revision to earthquake probability is achievable when a perturbing event is very close to the fault in question or the tectonic stressing rate is low.

  14. GIS learning tool for world's largest earthquakes and their causes

    NASA Astrophysics Data System (ADS)

    Chatterjee, Moumita

    The objective of this thesis is to increase awareness about earthquakes among people, especially young students by showing the five largest and two most predictable earthquake locations in the world and their plate tectonic settings. This is a geographic based interactive tool which could be used for learning about the cause of great earthquakes in the past and the safest places on the earth in order to avoid direct effect of earthquakes. This approach provides an effective way of learning for the students as it is very user friendly and more aligned to the interests of the younger generation. In this tool the user can click on the various points located on the world map which will open a picture and link to the webpage for that point, showing detailed information of the earthquake history of that place including magnitude of quake, year of past quakes and the plate tectonic settings that made this place earthquake prone. Apart from knowing the earthquake related information students will also be able to customize the tool to suit their needs or interests. Students will be able to add/remove layers, measure distance between any two points on the map, select any place on the map and know more information for that place, create a layer from this set to do a detail analysis, run a query, change display settings, etc. At the end of this tool the user has to go through the earthquake safely guidelines in order to be safe during an earthquake. This tool uses Java as programming language and uses Map Objects Java Edition (MOJO) provided by ESRI. This tool is developed for educational purpose and hence its interface has been kept simple and easy to use so that students can gain maximum knowledge through it instead of having a hard time to install it. There are lots of details to explore which can help more about what a GIS based tool is capable of. Only thing needed to run this tool is latest JAVA edition installed in their machine. This approach makes study more fun and

  15. Earthquake nucleation by transient deformations caused by the M = 7.9 Denali, Alaska, earthquake

    USGS Publications Warehouse

    Gomberg, J.; Bodin, P.; Larson, K.; Dragert, H.

    2004-01-01

    The permanent and dynamic (transient) stress changes inferred to trigger earthquakes are usually orders of magnitude smaller than the stresses relaxed by the earthquakes themselves, implying that triggering occurs on critically stressed faults. Triggered seismicity rate increases may therefore be most likely to occur in areas where loading rates are highest and elevated pore pressures, perhaps facilitated by high-temperature fluids, reduce frictional stresses and promote failure. Here we show that the 2002 magnitude M = 7.9 Denali, Alaska, earthquake triggered wide-spread seismicity rate increases throughout British Columbia and into the western United States. Dynamic triggering by seismic waves should be enhanced in directions where rupture directivity focuses radiated energy, and we verify this using seismic and new high-sample GPS recordings of the Denali mainshock. These observations are comparable in scale only to the triggering caused by the 1992 M = 7.4 Landers, California, earthquake, and demonstrate that Landers triggering did not reflect some peculiarity of the region or the earthquake. However, the rate increases triggered by the Denali earthquake occurred in areas not obviously tectonically active, implying that even in areas of low ambient stressing rates, faults may still be critically stressed and that dynamic triggering may be ubiquitous and unpredictable.

  16. Mechanical and Statistical Evidence of Human-Caused Earthquakes - A Global Data Analysis

    NASA Astrophysics Data System (ADS)

    Klose, C. D.

    2012-12-01

    The causality of large-scale geoengineering activities and the occurrence of earthquakes with magnitudes of up to M=8 is discussed and mechanical and statistical evidence is provided. The earthquakes were caused by artificial water reservoir impoundments, underground and open-pit mining, coastal management, hydrocarbon production and fluid injections/extractions. The presented global earthquake catalog has been recently published in the Journal of Seismology and is available for the public at www.cdklose.com. The data show evidence that geomechanical relationships exist with statistical significance between a) seismic moment magnitudes of observed earthquakes, b) anthropogenic mass shifts on the Earth's crust, and c) lateral distances of the earthquake hypocenters to the locations of the mass shifts. Research findings depend on uncertainties, in particular, of source parameter estimations of seismic events before instrumental recoding. First analyses, however, indicate that that small- to medium size earthquakes (M6) tend to be triggered. The rupture propagation of triggered events might be dominated by pre-existing tectonic stress conditions. Besides event specific evidence, large earthquakes such as China's 2008 M7.9 Wenchuan earthquake fall into a global pattern and can not be considered as outliers or simply seen as an act of god. Observations also indicate that every second seismic event tends to occur after a decade, while pore pressure diffusion seems to only play a role when injecting fluids deep underground. The chance of an earthquake to nucleate after two or 20 years near an area with a significant mass shift is 25% or 75% respectively. Moreover, causative effects of seismic activities highly depend on the tectonic stress regime in the Earth's crust in which geoengineering takes place.

  17. What caused a large number of fatalities in the Tohoku earthquake?

    NASA Astrophysics Data System (ADS)

    Ando, M.; Ishida, M.; Nishikawa, Y.; Mizuki, C.; Hayashi, Y.

    2012-04-01

    The Mw9.0 earthquake caused 20,000 deaths and missing persons in northeastern Japan. 115 years prior to this event, there were three historical tsunamis that struck the region, one of which is a "tsunami earthquake" resulted with a death toll of 22,000. Since then, numerous breakwaters were constructed along the entire northeastern coasts and tsunami evacuation drills were carried out and hazard maps were distributed to local residents on numerous communities. However, despite the constructions and preparedness efforts, the March 11 Tohoku earthquake caused numerous fatalities. The strong shaking lasted three minutes or longer, thus all residents recognized that this is the strongest and longest earthquake that they had been ever experienced in their lives. The tsunami inundated an enormous area at about 560km2 over 35 cities along the coast of northeast Japan. To find out the reasons behind the high number of fatalities due to the March 11 tsunami, we interviewed 150 tsunami survivors at public evacuation shelters in 7 cities mainly in Iwate prefecture in mid-April and early June 2011. Interviews were done for about 30min or longer focused on their evacuation behaviors and those that they had observed. On the basis of the interviews, we found that residents' decisions not to evacuate immediately were partly due to or influenced by earthquake science results. Below are some of the factors that affected residents' decisions. 1. Earthquake hazard assessments turned out to be incorrect. Expected earthquake magnitudes and resultant hazards in northeastern Japan assessed and publicized by the government were significantly smaller than the actual Tohoku earthquake. 2. Many residents did not receive accurate tsunami warnings. The first tsunami warning were too small compared with the actual tsunami heights. 3. The previous frequent warnings with overestimated tsunami height influenced the behavior of the residents. 4. Many local residents above 55 years old experienced

  18. 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.

  19. Mitigating mass movement caused by earthquakes and typhoons: a case study of central Taiwan

    NASA Astrophysics Data System (ADS)

    Lin, Jiun-Chuan

    2013-04-01

    Typhoons caused huge damages to Taiwan at the average of 3.8 times a year in the last 100 years, according to Central Weather Bureau data. After the Chi-Chi earthquake of 1999 at the magnitude of Richard Scale 7.3, typhoons with huge rainfall would cause huge debris flow and deposits at river channels. As a result of earthquakes, loose debris falls and flows became significant hazards in central Taiwan. Analysis of rainfall data and data about the sites of slope failure show that damage from natural hazards was enhanced in the last 20 years, as a result of the Chi-Chi earthquake. There are three main types of mass movement in Central Taiwan: landslides, debris flows and gully erosion. Landslides occurred mainly along hill slopes and river channel banks. Many dams, check dams, housing structures and even river channels can be raised to as high as 60 meters as a result of stacking up floating materials of landslides. Debris flows occurred mainly through typhoon periods and activated ancient debris deposition. New gullies were thus developed from deposits loosened and shaken up by earthquakes. Extreme earthquakes and typhoon events occurred frequently in the last 20 years. This paper analyzes the geological and geomorphologic background for the precarious areas and typhoons in central Taiwan, to make a systematic understanding of mass movement harzards. The mechanism and relations of debris flows and rainfall data in central Taiwan are analyzed. Ways for mitigating mass movement threats are also proposed in this paper. Keywords: mass movement, earthquakes, typhoons, hazard mitigation, central Ta

  20. Low magnitude earthquakes generating significant subsidence: the Lunigiana case study

    NASA Astrophysics Data System (ADS)

    Samsonov, S. V.; Polcari, M.; Melini, D.; Cannelli, V.; Moro, M.; Bignami, C.; Saroli, M.; Vannoli, P.; Stramondo, S.

    2013-12-01

    We applied the Differential Interferometric Synthetic Aperture Radar (DInSAR) technique to investigate and measure surface displacements due to the ML 5.2, June 21, 2013, earthquake occurred in the Apuan Alps (NW Italy) at a depth of about 5 km. The Centroid Moment Tensor (CMT) solution from INGV indicates an almost pure normal fault mechanism. Two differential interferograms showing the coseismic displacement were generated using X- band and C-band data respectively. The X-Band interferogram was obtained from a Cosmo-SkyMed ascending pair (azimuth -7.9° and incidence angle 40°) with a time interval of one day (June 21 - June 22) and 139 m spatial baseline, covering an area of about 40x40 km around the epicenter. The topographic phase component was removed using the 90 m SRTM DEM. The C-Band interferferogram was computed from two RADARSAT-2 Standard-3 (S3) images, characterized by 24 days temporal and 69 m spatial baselines, acquired on June 18 and July 12, 2013 on ascending orbit (azimuth -10.8°) with an incidence angle of 34° and covering 100x100 km area around the epicenter. The topographic phase component was removed using 30 m ASTER DEM. Adaptive filtering, phase unwrapping with Minimum Cost Flow (MCF) algorithm and orbital refinement were also applied to both interferograms. We modeled the observed SAR deformation fields using the Okada analytical formulation within a nonlinear inversion scheme, and found them to be consistent with a fault plane dipping towards NW at an angle of about 45°. In spite of the small magnitude, this earthquake produces a surface subsidence of about 1.5 cm in the Line-Of-Sight (LOS) direction, corresponding to about 3 cm along the vertical axis, that can be observed in both interferograms and appears consistent with the normal fault mechanisms.

  1. An earthquake in Japan caused large waves in Norwegian fjords

    NASA Astrophysics Data System (ADS)

    Schult, Colin

    2013-08-01

    Early on a winter morning a few years ago, many residents of western Norway who lived or worked along the shores of the nation's fjords were startled to see the calm morning waters suddenly begin to rise and fall. Starting at around 7:15 A.M. local time and continuing for nearly 3 hours, waves up to 1.5 meters high coursed through the previously still fjord waters. The scene was captured by security cameras and by people with cell phones, reported to local media, and investigated by a local newspaper. Drawing on this footage, and using a computational model and observations from a nearby seismic station, Bondevik et al. identified the cause of the waves—the powerful magnitude 9.0 Tohoku earthquake that hit off the coast of Japan half an hour earlier.

  2. Temporal stress changes caused by earthquakes: A review

    USGS Publications Warehouse

    Hardebeck, Jeanne L.; Okada, Tomomi

    2018-01-01

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

  3. Temporal Stress Changes Caused by Earthquakes: A Review

    NASA Astrophysics Data System (ADS)

    Hardebeck, Jeanne L.; Okada, Tomomi

    2018-02-01

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

  4. Investigating landslides caused by earthquakes - A historical review

    USGS Publications Warehouse

    Keefer, D.K.

    2002-01-01

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

  5. Age and significance of earthquake-induced liquefaction near Vancouver, British Columbia, Canada

    USGS Publications Warehouse

    Clague, J.J.; Naesgaard, E.; Nelson, A.R.

    1997-01-01

    In late 1994, sand dykes, large sand blows, and deformed strata were exposed in the walls of an excavation at Annacis Island on the Fraser River delta near Vancouver, British Columbia. The features record liquefaction during a large earthquake about 1700 years ago; this was perhaps the largest earthquake to affect the Vancouver area in the last 3500 years. Similar, less well-dated features have been reported from several other sites on the Fraser delta and may be products of the same earthquake. Three radiocarbon ages that closely delimit the time of liquefaction on Annacis Island are similar to the most precise radiocarbon ages on coseismically subsided marsh soils at estuaries in southern Washington and Oregon. Both the liquefaction and the subsidence may have been produced by a single great plate-boundary earthquake at the Cascadia subduction zone. Alternatively, liquefaction at Annacis Island may have been caused by a large crustal or subcrustal earthquake of about the same age as a plate-boundary earthquake farther west. The data from Annacis Island and other sites on the Fraser delta suggest that earthquakes capable of producing extensive liquefaction in this area are rare events. Further, liquefaction analysis using historical seismicity suggests that current assessment procedures may overestimate liquefaction risk.

  6. Investigating Landslides Caused by Earthquakes A Historical Review

    NASA Astrophysics Data System (ADS)

    Keefer, David K.

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

  7. Testing earthquake prediction algorithms: Statistically significant advance prediction of the largest earthquakes in the Circum-Pacific, 1992-1997

    USGS Publications Warehouse

    Kossobokov, V.G.; Romashkova, L.L.; Keilis-Borok, V. I.; Healy, J.H.

    1999-01-01

    Algorithms M8 and MSc (i.e., the Mendocino Scenario) were used in a real-time intermediate-term research prediction of the strongest earthquakes in the Circum-Pacific seismic belt. Predictions are made by M8 first. Then, the areas of alarm are reduced by MSc at the cost that some earthquakes are missed in the second approximation of prediction. In 1992-1997, five earthquakes of magnitude 8 and above occurred in the test area: all of them were predicted by M8 and MSc identified correctly the locations of four of them. The space-time volume of the alarms is 36% and 18%, correspondingly, when estimated with a normalized product measure of empirical distribution of epicenters and uniform time. The statistical significance of the achieved results is beyond 99% both for M8 and MSc. For magnitude 7.5 + , 10 out of 19 earthquakes were predicted by M8 in 40% and five were predicted by M8-MSc in 13% of the total volume considered. This implies a significance level of 81% for M8 and 92% for M8-MSc. The lower significance levels might result from a global change in seismic regime in 1993-1996, when the rate of the largest events has doubled and all of them become exclusively normal or reversed faults. The predictions are fully reproducible; the algorithms M8 and MSc in complete formal definitions were published before we started our experiment [Keilis-Borok, V.I., Kossobokov, V.G., 1990. Premonitory activation of seismic flow: Algorithm M8, Phys. Earth and Planet. Inter. 61, 73-83; Kossobokov, V.G., Keilis-Borok, V.I., Smith, S.W., 1990. Localization of intermediate-term earthquake prediction, J. Geophys. Res., 95, 19763-19772; Healy, J.H., Kossobokov, V.G., Dewey, J.W., 1992. A test to evaluate the earthquake prediction algorithm, M8. U.S. Geol. Surv. OFR 92-401]. M8 is available from the IASPEI Software Library [Healy, J.H., Keilis-Borok, V.I., Lee, W.H.K. (Eds.), 1997. Algorithms for Earthquake Statistics and Prediction, Vol. 6. IASPEI Software Library]. ?? 1999 Elsevier

  8. Gas and Dust Phenomena of Mega-earthquakes and the Cause

    NASA Astrophysics Data System (ADS)

    Yue, Z.

    2013-12-01

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

  9. Possible cause for an improbable earthquake: The 1997 MW 4.9 southern Alabama earthquake and hydrocarbon recovery

    USGS Publications Warehouse

    Gomberg, J.; Wolf, L.

    1999-01-01

    Circumstantial and physical evidence indicates that the 1997 MW 4.9 earthquake in southern Alabama may have been related to hydrocarbon recovery. Epicenters of this earthquake and its aftershocks were located within a few kilometers of active oil and gas extraction wells and two pressurized injection wells. Main shock and aftershock focal depths (2-6 km) are within a few kilometers of the injection and withdrawal depths. Strain accumulation at geologic rates sufficient to cause rupture at these shallow focal depths is not likely. A paucity of prior seismicity is difficult to reconcile with the occurrence of an earthquake of MW 4.9 and a magnitude-frequency relationship usually assumed for natural earthquakes. The normal-fault main-shock mechanism is consistent with reactivation of preexisting faults in the regional tectonic stress field. If the earthquake were purely tectonic, however, the question arises as to why it occurred on only the small fraction of a large, regional fault system coinciding with active hydrocarbon recovery. No obvious temporal correlation is apparent between the earthquakes and recovery activities. Although thus far little can be said quantitatively about the physical processes that may have caused the 1997 sequence, a plausible explanation involves the poroelastic response of the crust to extraction of hydrocarbons.

  10. Widespread ground motion distribution caused by rupture directivity during the 2015 Gorkha, Nepal earthquake

    NASA Astrophysics Data System (ADS)

    Koketsu, Kazuki; Miyake, Hiroe; Guo, Yujia; Kobayashi, Hiroaki; Masuda, Tetsu; Davuluri, Srinagesh; Bhattarai, Mukunda; Adhikari, Lok Bijaya; Sapkota, Soma Nath

    2016-06-01

    The ground motion and damage caused by the 2015 Gorkha, Nepal earthquake can be characterized by their widespread distributions to the east. Evidence from strong ground motions, regional acceleration duration, and teleseismic waveforms indicate that rupture directivity contributed significantly to these distributions. This phenomenon has been thought to occur only if a strike-slip or dip-slip rupture propagates to a site in the along-strike or updip direction, respectively. However, even though the earthquake was a dip-slip faulting event and its source fault strike was nearly eastward, evidence for rupture directivity is found in the eastward direction. Here, we explore the reasons for this apparent inconsistency by performing a joint source inversion of seismic and geodetic datasets, and conducting ground motion simulations. The results indicate that the earthquake occurred on the underthrusting Indian lithosphere, with a low dip angle, and that the fault rupture propagated in the along-strike direction at a velocity just slightly below the S-wave velocity. This low dip angle and fast rupture velocity produced rupture directivity in the along-strike direction, which caused widespread ground motion distribution and significant damage extending far eastwards, from central Nepal to Mount Everest.

  11. Marcellus Shale fracking waste caused earthquakes in Ohio

    NASA Astrophysics Data System (ADS)

    Schultz, Colin

    2013-08-01

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

  12. [Psychological effects on medical students caused by earthquakes of 1985].

    PubMed

    Piña Barba, B; Torres Cosme, J L; Prawda Witemberg, M; Pérez Reséndiz, G

    1991-01-01

    Eight months after the earthquakes of September 1985 in Mexico City, an analysis about the psychological symptoms, commonly associated with traumatic experiences was performed, among a population of 708 students, coursing the first year of Medical School. By means of a questionnaire, they reported the symptoms they had experienced before the earthquakes, during the following two weeks, and at the moment of the survey was still higher symptoms at the moment of the survey was still higher than before the earthquakes, so eight months appear to be an insufficient lapse for the complete remission of new cases. About 15.8 per cent of the studied population reported symptomatology that can be considered as having been triggered by the earthquakes. Another sector of the population (11%), previously symptomatic, reported remission after the earthquakes. The group of students directly affected by severe injuries for deaths of either family members, cohabiting persons, or of persons with whom strong affective ties prevailed, showed a greater tendency to present symptomatic states. Women represented the group most affected psychologically by the earthquakes.

  13. Reverberations on the watery element: A significant, tsunamigenic historical earthquake offshore the Carolina coast

    USGS Publications Warehouse

    Hough, Susan E.; Munsey, Jeffrey; Ward, Steven N.

    2013-01-01

    We investigate an early nineteenth‐century earthquake that has been previously cataloged but not previously investigated in detail or recognized as a significant event. The earthquake struck at approximately 4:30 a.m. LT on 8 January 1817 and was widely felt throughout the southeastern and mid‐Atlantic United States. Around 11:00 a.m. the same day, an eyewitness described a 12‐inch tide that rose abruptly and agitated boats on the Delaware River near Philadelphia. We show that the timing of this tide is consistent with the predicted travel time for a tsunami generated by an offshore earthquake 6–7 hours earlier. By combining constraints provided by the shaking intensity distribution and the tsunami observation, we conclude that the 1817 earthquake had a magnitude of low‐ to mid‐M 7 and a location 800–1000 km offshore of South Carolina. Our results suggest that poorly understood offshore source zones might represent a previously unrecognized hazard to the southern and mid‐Atlantic coast. Both observational and modeling results indicate that potential tsunami hazard within Delaware Bay merits consideration: the simple geometry of the bay appears to catch and focus tsunami waves. Our preferred location for the 1817 earthquake is along a diffuse northeast‐trending zone defined by instrumentally recorded and historical earthquakes. The seismotectonic framework for this region remains enigmatic.

  14. Toward resolving an earthquake ground motion mystery in west Seattle, Washington State: Shallow seismic focusing may cause anomalous chimney damage

    USGS Publications Warehouse

    Stephenson, W.J.; Frankel, A.D.; Odum, J.K.; Williams, R.A.; Pratt, T.L.

    2006-01-01

    A shallow bedrock fold imaged by a 1.3-km long high-resolution shear-wave seismic reflection profile in west Seattle focuses seismic waves arriving from the south. This focusing may cause a pocket of amplified ground shaking and the anomalous chimney damage observed in earthquakes of 1949, 1965 and 2001. The 200-m bedrock fold at ???300-m depth is caused by deformation across an inferred fault within the Seattle fault zone. Ground motion simulations, using the imaged geologic structure and northward-propagating north-dipping plane wave sources, predict a peak horizontal acceleration pattern that matches that observed in strong motion records of the 2001 Nisqually event. Additionally, a pocket of chimney damage reported for both the 1965 and the 2001 earthquakes generally coincides with a zone of simulated amplification caused by focusing. This study further demonstrates the significant impact shallow (<1km) crustal structures can have on earthquake ground-motion variability.

  15. Environmental impact of the landslides caused by the 12 May 2008, Wenchuan, China earthquake

    USGS Publications Warehouse

    Highland, Lynn; Sun, Ping; Edited by Margottini, Claudio; Canuti, Paolo; Sassa, Kyoji

    2013-01-01

    The magnitude 7.9 (Mw) Wenchuan, China, earthquake of May 12, 2008 caused at least 88,000 deaths of which one third are estimated to be due to the more than 56,000 earthquake-induced landslides. The affected area is mountainous, featuring densely-vegetated, steep slopes through which narrowly confined rivers and streams flow. Numerous types of landslides occurred in the area, including rock avalanches, rock falls, translational and rotational slides, lateral spreads and debris flows. Some landslides mobilized hundreds of million cubic meters of material, often resulting in the damming of rivers and streams, impacting river ecosystems and morphology. Through an extensive search of both Chinese- and English-language publications we provide a summary of pertinent research on environmental effects, emphasizing key findings. Environmental effects caused by landslides include the alteration of agriculture, changes to natural ecosystems, changes in river morphology due to landslide dams and other effects such as sedimentation and flooding. Damage by landslides to the giant panda reserve infrastructure and habitat, was severe, threatening the survival of one of the world’s rarest species. The Panda reserves are of national significance to China, and to the vital tourism economy of the region. One of the major impacts to both the natural and built environment is the complete relocation of some human populations and infrastructure to new areas, resulting in the abandonment of towns and other areas that were damaged by the earthquake and landslides. The landslide effects have affected the biodiversity of the affected area, and it has been hypothesized that strict forest preservation measures taken in the years preceding the earthquake resulted in a reduction of the environmental damage to the area.

  16. Earthquakes.

    ERIC Educational Resources Information Center

    Pakiser, Louis C.

    One of a series of general interest publications on science topics, the booklet provides those interested in earthquakes with an introduction to the subject. Following a section presenting an historical look at the world's major earthquakes, the booklet discusses earthquake-prone geographic areas, the nature and workings of earthquakes, earthquake…

  17. Relocation of earthquakes at southwestern Indian Ocean Ridge and its tectonic significance

    NASA Astrophysics Data System (ADS)

    Luo, W.; Zhao, M.; Haridhi, H.; Lee, C. S.; Qiu, X.; Zhang, J.

    2015-12-01

    The southwest Indian Ridge (SWIR) is a typical ultra-slow spreading ridge (Dick et al., 2003) and further plate boundary where the earthquakes often occurred. Due to the lack of the seismic stations in SWIR, positioning of earthquakes and micro-earthquakes is not accurate. The Ocean Bottom Seismometers (OBS) seismic experiment was carried out for the first time in the SWIR 49 ° 39 'E from Jan. to March, 2010 (Zhao et al., 2013). These deployed OBS also recorded the earthquakes' waveforms during the experiment. Two earthquakes occurred respectively in Feb. 7 and Feb. 9, 2010 with the same magnitude of 4.4 mb. These two earthquakes were relocated using the software HYPOSAT based on the spectrum analysis and band-pass (3-5 Hz) filtering and picking up the travel-times of Pn and Sn. Results of hypocentral determinations show that there location error is decreased significantly by joined OBS's recording data. This study do not only provide the experiences for the next step deploying long-term wide-band OBSs, but also deepen understanding of the structure of SWIR and clarify the nature of plate tectonic motivation. This research was granted by the Natural Science Foundation of China (41176053, 91028002, 91428204). Keywords: southwest Indian Ridge (SWIR), relocation of earthquakes, Ocean Bottom Seismometers (OBS), HYPOSAT References:[1] Dick, H. J. B., Lin J., Schouten H. 2003. An ultraslow-spreading class of ocean ridge. Nature, 426(6965): 405-412. [2] Zhao M. H., et al. 2013. Three-dimensional seismic structure of the Dragon Flag oceanic core complex at the ultraslow spreading Southwest Indian Ridge (49°39' E). Geochemistry Geophysics Geosystems, 14(10): 4544-4563.

  18. The 2008 M7.9 Wenchuan earthquake - a human-caused event

    NASA Astrophysics Data System (ADS)

    Klose, C. D.

    2013-12-01

    A catalog of global human-caused earthquakes shows statistical evidence that the triggering of earthquakes by large-scale geoengineering activities depends on geological and tectonic constrains (in Klose 2013). Such geoengineering activities also include the filling of water reservoirs. This presentation illuminates mechanical and statistical aspects of the 2008 M7.9 Wenchuan earthquake in light of the hypothesis of being NOT human-caused. However, available data suggest that the Wenchuan earthquake was triggered by the filling of the Zipungpu water reservoir 30 months prior to the mainshock. The reservoir spatially extended parallel and near to the main Beichuan fault zone in a highly stressed reverse fault regime. It is mechanically evident that reverse faults tend to be very trigger-sensitive due to mass shifts (static loads) that occur on the surface of the Earth's crust. These circumstances made a triggering of a seismic event of this magnitude at this location possible (in Klose 2008, 2012). The data show that the Wenchuan earthquake is not an outlier. From a statistical view point, the earthquake falls into the upper range of the family of reverse fault earthquakes that were caused by humans worldwide.

  19. Localized damage caused by topographic amplification during the 2010 M7.0 Haiti earthquake

    USGS Publications Warehouse

    Hough, S.E.; Altidor, J.R.; Anglade, D.; Given, D.; Janvier, M.G.; Maharrey, J.Z.; Meremonte, M.; Mildor, B.S.-L.; Prepetit, C.; Yong, A.

    2010-01-01

    Local geological conditions, including both near-surface sedimentary layers and topographic features, are known to significantly influence ground motions caused by earthquakes. Microzonation maps use local geological conditions to characterize seismic hazard, but commonly incorporate the effect of only sedimentary layers. Microzonation does not take into account local topography, because significant topographic amplification is assumed to be rare. Here we show that, although the extent of structural damage in the 2010 Haiti earthquake was primarily due to poor construction, topographic amplification contributed significantly to damage in the district of Petionville, south of central Port-au-Prince. A large number of substantial, relatively well-built structures situated along a foothill ridge in this district sustained serious damage or collapse. Using recordings of aftershocks, we calculate the ground motion response at two seismic stations along the topographic ridge and at two stations in the adjacent valley. Ground motions on the ridge are amplified relative to both sites in the valley and a hard-rock reference site, and thus cannot be explained by sediment-induced amplification. Instead, the amplitude and predominant frequencies of ground motion indicate the amplification of seismic waves by a narrow, steep ridge. We suggest that microzonation maps can potentially be significantly improved by incorporation of topographic effects. ?? 2010 Macmillan Publishers Limited. All rights reserved.

  20. The Cause of the Cauca, Colombia, Cluster of Intermediate-Depth Earthquakes From Earthquake Relocation and Focal Mechanisms

    NASA Astrophysics Data System (ADS)

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

    2016-12-01

    In subducting slabs, a high seismicity rate in a concentrated volume (an earthquake cluster) is often associated with geometric complexities such as slab detachment, tearing, or contortions. The intermediate-depth Cauca, Colombia, cluster (3.5°N-5.5°N), in contrast, appears to be located in a slab without such complexities. However, previous constraints on the slab geometry are based on global data. We use regional data to investigate the cause of the Cauca cluster by estimating its geometry from earthquake relocations and stress regime from focal mechanism calculations and stress inversions. The Cauca segment of the Nazca Plate is characterized by relatively sparse seismicity away from the cluster and a narrow volcanic arc. To the northeast of the Cauca cluster, six active volcanoes are concentrated within an 80-km along-trench distance and are isolated 180 km from the rest of the northern Andes volcanic arc. The Colombian National Seismic Network, from Jan 2010 to Mar 2014, reports 433 earthquakes in the cluster at depths of 50-200 km with local magnitudes ranging from 2.0-4.7. Earthquake relocations show a continuous 20-km-thick seismic zone dipping at 33°-43°, with the angle increasing to the south. In addition, earthquakes locate in two columns that extend normal to the slab and into the mantle wedge. The focal mechanisms show various types, including down-dip extension, strike slip, and trench-parallel compression, but are consistent with a predominantly down-dip extensional stress field. The maximum and intermediate stress axes are interchangeable because of their similar magnitudes. The down-dip extensional stress regime may expel dehydrated fluid from the slab into the mantle wedge. As the fluid moves through the mantle wedge, it may generate hydrofractures and the observed mantle-wedge earthquakes. The fluid in the mantle wedge may be transported along the trench, from the steeper southern section to the more shallowly-dipping northern section, and

  1. Factors influencing to earthquake caused economical losses on urban territories

    NASA Astrophysics Data System (ADS)

    Nurtaev, B.; Khakimov, S.

    2005-12-01

    Questions of assessment of earthquake economical losses on urban territories of Uzbekistan, taking into account damage forming factors, which are increqasing or reducing economical losses were discussed in the paper. Buildings and facilities vulnerability factors were classified. From total value (equal to 50) were selected most important ones. Factors ranging by level of impact and weight function in loss assessment were ranged. One group of damage forming factors includs seismic hazard assessment, design, construction and maintenance of building and facilities. Other one is formed by city planning characteristics and includes : density of constructions and population, area of soft soils, existence of liquefaction susceptible soils and etc. To all these factors has been given weight functions and interval values by groups. Methodical recomendations for loss asessment taking into account above mentioned factors were developed. It gives possibility to carry out preventive measures for protection of vulnerable territories, to differentiate cost assessment of each region in relation with territory peculiarity and damage value. Using developed method we have ranged cities by risk level. It has allowed to establish ratings of the general vulnerability of urban territories of cities and on their basis to make optimum decisions, oriented to loss mitigation and increase of safety of population. Besides the technique can be used by insurance companies for estimated zoning of territory, development of effective utilization schema of land resources, rational town-planning, an economic estimation of used territory for supply with information of the various works connected to an estimation of seismic hazard. Further improvement of technique of establishment of rating of cities by level of damage from earthquakes will allow to increase quality of construction, rationality of accommodation of buildings, will be an economic stimulator for increasing of seismic resistance of

  2. Spatiotemporal variations in the b-value of earthquake magnitude-frequency distributions: Classification and causes

    NASA Astrophysics Data System (ADS)

    El-Isa, Z. H.; Eaton, David W.

    2014-03-01

    Interpretation of the b-value of earthquake frequency-magnitude distributions has received considerable attention in recent decades. This paper provides a comprehensive review of previous investigations of spatial and temporal variations in b-value, including their classification and possible causes. Based on least-squares regression of seismicity data compiled from the NEIC, IRIS and ISC catalogs, we find an average value of 1.02 ± 0.03 for the whole Earth and its two hemispheres, consistent with the general view that in seismically active regions the long-term average value is close to unity. Nevertheless, wide-ranging b-variations (0.3 ≤ b ≤ 2.5) have been reported in the literature. This variability has been interpreted to arise from one or more of the following factors: prevailing stress state, crustal heterogeneity, focal depth, pore pressure, geothermal gradient, tectonic setting, petrological/environmental/geophysical characteristics, clustering of events, incomplete catalog data, and/or method of calculation. Excluding the latter, all of these factors appear to be linked, directly or indirectly, with the effective state of stress. Although time-dependent changes in b-value are well documented, conflicting observations reveal either a precursory increase or decrease in b value before major earthquakes. Our compilation of published analyses suggests that statistically significant b-variations occur globally on various timescales, including annual, monthly and perhaps diurnal. Taken together, our review suggests that b-variations are most plausibly linked with changes in effective stress.

  3. Significant earthquakes on the Enriquillo fault system, Hispaniola, 1500-2010: Implications for seismic hazard

    USGS Publications Warehouse

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

    2012-01-01

    Historical records indicate frequent seismic activity along the north-east Caribbean plate boundary over the past 500 years, particularly on the island of Hispaniola. We use accounts of historical earthquakes to assign intensities and the intensity assignments for the 2010 Haiti earthquakes to derive an intensity attenuation relation for Hispaniola. The intensity assignments and the attenuation relation are used in a grid search to find source locations and magnitudes that best fit the intensity assignments. Here we describe a sequence of devastating earthquakes on the Enriquillo fault system in the eighteenth century. An intensity magnitude MI 6.6 earthquake in 1701 occurred near the location of the 2010 Haiti earthquake, and the accounts of the shaking in the 1701 earthquake are similar to those of the 2010 earthquake. A series of large earthquakes migrating from east to west started with the 18 October 1751 MI 7.4–7.5 earthquake, probably located near the eastern end of the fault in the Dominican Republic, followed by the 21 November 1751 MI 6.6 earthquake near Port-au-Prince, Haiti, and the 3 June 1770 MI 7.5 earthquake west of the 2010 earthquake rupture. The 2010 Haiti earthquake may mark the beginning of a new cycle of large earthquakes on the Enriquillo fault system after 240 years of seismic quiescence. The entire Enriquillo fault system appears to be seismically active; Haiti and the Dominican Republic should prepare for future devastating earthquakes.

  4. Co-located ionospheric and geomagnetic disturbances caused by great earthquakes

    NASA Astrophysics Data System (ADS)

    Hao, Yongqiang; Zhang, Donghe; Xiao, Zuo

    2016-07-01

    Despite primary energy disturbances from the Sun, oscillations of the Earth surface due to a large earthquake will couple with the atmosphere and therefore the ionosphere, to generate so-called coseismic ionospheric disturbances (CIDs). In the cases of 2008 Wenchuan and 2011 Tohoku earthquakes, infrasonic waves accompanying the propagation of seismic Rayleigh waves were observed in the ionosphere by a combination of techniques, total electron content, HF Doppler, and ground magnetometer. This is the very first report to present CIDs recorded by different techniques at co-located sites and profiled with regard to changes of both ionospheric plasma and current (geomagnetic field) simultaneously. Comparison between the oceanic (2011 Tohoku) and inland (2008 Wenchuan) earthquakes revealed that the main directional lobe of latter case is more distinct which is perpendicular to the direction of the fault rupture. We argue that the different fault slip (inland or submarine) may affect the way of couplings of lithosphere with atmosphere. Zhao, B., and Y. Hao (2015), Ionospheric and geomagnetic disturbances caused by the 2008 Wenchuan earthquake: A revisit, J. Geophys. Res., doi:10.1002/2015JA021035. Hao, Y. Q., et al. (2013), Teleseismic magnetic effects (TMDs) of 2011 Tohoku earthquake, J. Geophys. Res., doi:10.1002/jgra.50326. Hao, Y. Q., et al. (2012), Multi-instrument observation on co-seismic ionospheric effects after great Tohoku earthquake, J. Geophys. Res., doi:10.1029/2011JA017036.

  5. Proceedings of preparing for a significant Central United States earthquake-Science needs of the response and recovery community

    USGS Publications Warehouse

    Witt, Emitt C.

    2010-01-01

    Preface Imagine waking up at 2 o'clock in the morning by a violent rumbling that causes ceilings to fall, furniture to topple over, and windows to break. Your home is crumbling, it is dark, and by the time you realize what is going on the shaking stops. You quickly determine that your family members are okay, but you also realize your power is out, all the windows are broken, and there is substantial damage to your home possibly making it unsafe to remain inside. The temperature outside is in the 20s, there is a heavy snow on the ground, and the flu season is at its peak with two of your family members affected. Unfortunately your family is one of thousands in a similar circumstance and the response to your needs may not be immediate, if at all. Could an earthquake like this happen unannounced? It did in the Central United States during the great New Madrid earthquake of 1811-12. A resident of New Madrid, Missouri writes (Martin, 1848 ): 'On the 16th of December 1811, about 2 o'clock, AM, we were visited by a violent shock of an earthquake accompanied by a very awful noise resembling loud but distant thunder, but more hoarse and vibrating, which was followed in a few minutes by the complete saturation of the atmosphere with sulphurious vapor, causing total darkness. The screams of the affrighted inhabitants running to and fro, not knowing where to go, or what to do-the cries of the fowls and beasts of every species-the crackling of trees falling, and the roar of the Mississippi-the current of which was retrograde for a few minutes, owing as is supposed to an irruption in its bed-formed a scene truly horrible.' Eliza Bryan, March 22, 1816 The residents of the Central United States during the great New Madrid earthquake were accustomed to living rugged life styles. Electrical power was not a reality, water was drawn from shallow hand-dug wells or retrieved from streams, food was hunted or grown, and the homes typically were log structures with dirt floors. Though

  6. 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...

  7. 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)

  8. On relating apparent stress to the stress causing earthquake fault slip

    USGS Publications Warehouse

    McGarr, A.

    1999-01-01

    Apparent stress ??a is defined as ??a = ??????, where ???? is the average shear stress loading the fault plane to cause slip and ?? is the seismic efficiency, defined as Ea/W, where Ea is the energy radiated seismically and W is the total energy released by the earthquake. The results of a recent study in which apparent stresses of mining-induced earthquakes were compared to those measured for laboratory stick-slip friction events led to the hypothesis that ??a/???? ??? 0.06. This hypothesis is tested here against a substantially augmented data set of earthquakes for which ???? can be estimated, mostly from in situ stress measurements, for comparison with ??a. The expanded data set, which includes earthquakes artificially triggered at a depth of 9 km in the German Kontinentales Tiefbohrprogramm der Bundesrepublik Deutschland (KTB) borehole and natural tectonic earthquakes, covers a broad range of hypocentral depths, rock types, pore pressures, and tectonic settings. Nonetheless, over ???14 orders of magnitude in seismic moment, apparent stresses exhibit distinct upper bounds defined by a maximum seismic efficiency of ???0.06, consistent with the hypothesis proposed before. This behavior of ??a and ?? can be expressed in terms of two parameters measured for stick-slip friction events in the laboratory: the ratio of the static to the dynamic coefficient of friction and the fault slip overshoot. Typical values for these two parameters yield seismic efficiencies of ???0.06. In contrast to efficiencies for laboratory events for which ?? is always near 0.06, those for earthquakes tend to be less than this bounding value because Ea for earthquakes is usually underestimated due to factors such as band-limited recording. Thus upper bounds on ??a/???? appear to be controlled by just a few fundamental aspects of frictional stick-slip behavior that are common to shallow earthquakes everywhere. Estimates of ???? from measurements of ??a for suites of earthquakes, using ??a

  9. Significance for secure CO2 storage of earthquakes induced by fluid injection

    NASA Astrophysics Data System (ADS)

    Verdon, James P.

    2014-05-01

    The link between subsurface fluid injection and induced seismicity has gained recent significance with an increase in earthquakes associated with the disposal of oilfield waste fluids. There are obvious similarities between wastewater reinjection and proposed CO2 storage (CCS) operations. However, as well as the seismic hazard, induced seismicity during CCS operations poses additional risks, because an induced event located above the target reservoir could compromise the hydraulic integrity of the caprock. In this paper we re-examine case examples where earthquakes have been induced by wastewater injection into deep aquifers in the light of proposed future CCS operations. In particular we consider possible controls on event magnitudes, and look at the spatial distributions of events. We find that the majority of events are located below the target reservoirs. This is an encouraging observation from the perspective of caprock integrity, although it presents a challenge in terms of pre-injection characterization of deep-lying faults several kilometres below the target zone. We observe that 99% of events are found within 20 km of injection wells, suggesting a minimum radius for geomechanical characterization and monitoring. We conclude by making recommendations for modelling and monitoring strategies to be followed prior to and during commercial-scale deployment of CO2 storage projects.

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

    SciTech Connect

    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

  11. Expediting red blood cell transfusions by syringing causes significant hemolysis.

    PubMed

    De Villiers, Willem Lambertus; Murray, Adriaan Albertus; Levin, Andrew Ian

    2017-11-01

    Techniques commonly used to expedite blood transfusions include pneumatically pressurizing red blood cell (RBC) bags or manual syringing its contents. We compared these techniques on RBC hemolysis using a simulated transfusion model. Fifteen warmed RBC units that were 12.3 ± 4.3 (95% confidence interval [CI], 10.1-14.5) days old were each subjected to two experimental rapid transfusion techniques. RBCs from each technique were directed through 18- and 22-gauge cannulas attached to blood administration sets. One technique involved RBC bag pressurization to 300 mmHg. The other employed a 20-mL syringe to effect forceful, manual aspiration from the RBC bag followed by forceful, manual RBC injection. The control group was gravity driven without cannulas. Free hemoglobin (Hb) concentrations were measured and percent hemolysis was calculated. Free Hb concentrations and percent hemolysis (median [95% CI]) were similar in the control (0.05 [0.03-0.08] g/dL and 0.13% [0.09%-0.17%], respectively) and pressurized experiments (0.06 [0.05-0.09] g/dL; 0.14% [0.12%-0.22%]), respectively. Syringing resulted in 10-fold higher free Hb concentrations (0.55 [0.38-0.92] g/dL) and percent hemolysis (1.28% [1.03%-2.15%]) than when employing the control (p < 0.0001) or pressurization (p < 0.0001) techniques. Cannula sizes studied did not affect hemolysis. Forceful manual syringing caused significant hemolysis and high free Hb concentrations. Pressurizing RBC bags induced no more hemolysis than after gravity-facilitated transfusions. Syringing to expedite RBC transfusions should be avoided in favor of pneumatic RBC bag pressurization. © 2017 AABB.

  12. 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.

  13. Improving the RST Approach for Earthquake Prone Areas Monitoring: Results of Correlation Analysis among Significant Sequences of TIR Anomalies and Earthquakes (M>4) occurred in Italy during 2004-2014

    NASA Astrophysics Data System (ADS)

    Tramutoli, V.; Coviello, I.; Filizzola, C.; Genzano, N.; Lisi, M.; Paciello, R.; Pergola, N.

    2015-12-01

    Looking toward the assessment of a multi-parametric system for dynamically updating seismic hazard estimates and earthquake short term (from days to weeks) forecast, a preliminary step is to identify those parameters (chemical, physical, biological, etc.) whose anomalous variations can be, to some extent, associated to the complex process of preparation of a big earthquake. Among the different parameters, the fluctuations of Earth's thermally emitted radiation, as measured by sensors on board of satellite system operating in the Thermal Infra-Red (TIR) spectral range, have been proposed since long time as potential earthquake precursors. Since 2001, a general approach called Robust Satellite Techniques (RST) has been used to discriminate anomalous thermal signals, possibly associated to seismic activity from normal fluctuations of Earth's thermal emission related to other causes (e.g. meteorological) independent on the earthquake occurrence. Thanks to its full exportability on different satellite packages, RST has been implemented on TIR images acquired by polar (e.g. NOAA-AVHRR, EOS-MODIS) and geostationary (e.g. MSG-SEVIRI, NOAA-GOES/W, GMS-5/VISSR) satellite sensors, in order to verify the presence (or absence) of TIR anomalies in presence (absence) of earthquakes (with M>4) in different seismogenic areas around the world (e.g. Italy, Turkey, Greece, California, Taiwan, etc.).In this paper, a refined RST (Robust Satellite Techniques) data analysis approach and RETIRA (Robust Estimator of TIR Anomalies) index were used to identify Significant Sequences of TIR Anomalies (SSTAs) during eleven years (from May 2004 to December 2014) of TIR satellite records, collected over Italy by the geostationary satellite sensor MSG-SEVIRI. On the basis of specific validation rules (mainly based on physical models and results obtained by applying RST approach to several earthquakes all around the world) the level of space-time correlation among SSTAs and earthquakes (with M≥4

  14. Preliminary report on crustal deformation surveys and tsunami measurements caused by the July 17, 2006 South off Java Island Earthquake and Tsunami, Indonesia

    NASA Astrophysics Data System (ADS)

    Kato, T.; Ito, T.; Abidin, H. Z.; Agustan

    2007-09-01

    A large earthquake (Mw=7.7) along a plate boundary occurred in the south of Java Island on July 17, 2006, and caused a significant tsunami. We made GPS observations and tsunami heights measurements during the period from July 24 to August 1, 2006. The earthquake seems to be due to an interplate low angle reverse faulting, though there might be a possibility of high angle faulting within the subducting lithosphere. Crustal deformation distribution due to the earthquake, aided by tsunami heights measurements, might clarify which would be the case. We occupied 29 sites by GPS in the area of southern Java encompassing the area from 107.8 E to 109.50 E. These sites were occupied once before the earthquake. However, we were not able to detect significant co-seismic displacements. The obtained displacements, most of which span several years, show ESE direction in ITRF2000 frame. This represents the direction of Sunda block motion. The tsunami heights measured at 11 sites were 6-7 m along the southern coast of Java and indicate that the observed heights are systematically higher than those estimated from numerical simulations that are based on seismic data analysis. This might suggest that fault offsets might have been larger - nearly double - than those estimated using seismic analysis. These results lead us to an idea that the rupture was very slow. If this is the case, the earthquake might have been a "tsunami earthquake" that is similar to the one that occurred on June 2, 1994 in the east of the present earthquake.

  15. Social impacts of earthquakes caused by gas extraction in the Province of Groningen, The Netherlands

    SciTech Connect

    Voort, Nick van der, E-mail: nickvdvoort@gmail.com; Vanclay, Frank, E-mail: frank.vanclay@rug.nl

    Gas extraction from the Groningen gasfield in the northern Netherlands has led to localised earthquakes which are projected to become more severe. The social impacts experienced by local residents include: damage to property; declining house prices; concerns about the chance of dykes breaking; feelings of anxiety and insecurity; health issues; and anger. These social and emotional impacts are exacerbated by the increasing distrust Groningen people have towards the national government and the gas company, NAM, a partnership between Shell and ExxonMobil. The earthquakes have reopened discussions about the distribution of benefits from gas production and the extent to which benefitsmore » are retained locally. Mitigation of the impacts is attempted, but the lack of trust decreases the effectiveness of the mitigation measures. The extent of this experience of previously-unforeseen, unanticipated impacts suggests that a new social and environmental impact assessment needs to be undertaken, and a new Social Impact Management Plan (SIMP) and Impacts and Benefits Agreement (IBA) developed, so that the project can regain its legitimacy and social licence to operate. In addition to conventional gas, this paper has wider relevance for unconventional gas developments, for example shale gas extraction by hydraulic fracturing methods (fracking). - Highlights: • Gas production in Groningen has caused over 1000 earthquakes. • The induced seismicity has caused many social impacts. • Impacts include building damage, reduced house prices, fear and health issues. • Mitigation measures attempted to date are inadequate. • Distrust towards the national government and operator hinders mitigation efforts. • Gas production in Groningen has lost its social licence to operate.« less

  16. Significant Atmospheric Aerosol Pollution Caused by World Food Cultivation

    NASA Technical Reports Server (NTRS)

    Bauer, Susanne E.; Tsigaridis, Kostas; Miller, Ron

    2016-01-01

    Particulate matter is a major concern for public health, causing cancer and cardiopulmonary mortality. Therefore, governments in most industrialized countries monitor and set limits for particulate matter. To assist policy makers, it is important to connect the chemical composition and severity of particulate pollution to its sources. Here we show how agricultural practices, livestock production, and the use of nitrogen fertilizers impact near-surface air quality. In many densely populated areas, aerosols formed from gases that are released by fertilizer application and animal husbandry dominate over the combined contributions from all other anthropogenic pollution. Here we test reduction scenarios of combustion-based and agricultural emissions that could lower air pollution. For a future scenario, we find opposite trends, decreasing nitrate aerosol formation near the surface while total tropospheric loads increase. This suggests that food production could be increased to match the growing global population without sacrificing air quality if combustion emission is decreased.

  17. Significant atmospheric aerosol pollution caused by world food cultivation

    NASA Astrophysics Data System (ADS)

    Bauer, Susanne E.; Tsigaridis, Kostas; Miller, Ron

    2016-05-01

    Particulate matter is a major concern for public health, causing cancer and cardiopulmonary mortality. Therefore, governments in most industrialized countries monitor and set limits for particulate matter. To assist policy makers, it is important to connect the chemical composition and severity of particulate pollution to its sources. Here we show how agricultural practices, livestock production, and the use of nitrogen fertilizers impact near-surface air quality. In many densely populated areas, aerosols formed from gases that are released by fertilizer application and animal husbandry dominate over the combined contributions from all other anthropogenic pollution. Here we test reduction scenarios of combustion-based and agricultural emissions that could lower air pollution. For a future scenario, we find opposite trends, decreasing nitrate aerosol formation near the surface while total tropospheric loads increase. This suggests that food production could be increased to match the growing global population without sacrificing air quality if combustion emission is decreased.

  18. Significant atmospheric aerosol pollution caused by world food cultivation

    NASA Astrophysics Data System (ADS)

    Bauer, Susanne E.; Tsigaridis, Kostas; Miller, Ron

    2017-04-01

    Particulate matter is a major concern for public health, causing cancer and cardiopulmonary mortality. Therefore, governments in most industrialized countries monitor and set limits for particulate matter. To assist policy makers, it is important to connect the chemical composition and severity of particulate pollution to it s sources. Here we show how agricultural practices, livestock production, and the use of nitrogen fertilizers impact near-surface air quality. In many densely populated areas, aerosols formed from gases that are released by fertilizer application and animal husbandry dominate over the combined contributions from all other anthropogenic pollution. Here we test reduction scenarios of combustion-based and agricultural emissions that could lower air pollution. For a future scenario, we find opposite trends, decreasing nitrate aerosol formation near the surface while total tropospheric loads increase. This suggests that food production could be increased to match the growing global population without sacrificing air quality if combustion emission is decreased.

  19. Significance chasing in research practice: causes, consequences and possible solutions.

    PubMed

    Ware, Jennifer J; Munafò, Marcus R

    2015-01-01

    The low reproducibility of findings within the scientific literature is a growing concern. This may be due to many findings being false positives which, in turn, can misdirect research effort and waste money. We review factors that may contribute to poor study reproducibility and an excess of 'significant' findings within the published literature. Specifically, we consider the influence of current incentive structures and the impact of these on research practices. The prevalence of false positives within the literature may be attributable to a number of questionable research practices, ranging from the relatively innocent and minor (e.g. unplanned post-hoc tests) to the calculated and serious (e.g. fabrication of data). These practices may be driven by current incentive structures (e.g. pressure to publish), alongside the preferential emphasis placed by journals on novelty over veracity. There are a number of potential solutions to poor reproducibility, such as new publishing formats that emphasize the research question and study design, rather than the results obtained. This has the potential to minimize significance chasing and non-publication of null findings. Significance chasing, questionable research practices and poor study reproducibility are the unfortunate consequence of a 'publish or perish' culture and a preference among journals for novel findings. It is likely that top-down change implemented by those with the ability to modify current incentive structure (e.g. funders and journals) will be required to address problems of poor reproducibility. © 2014 Society for the Study of Addiction.

  20. Earthquake-caused subsidence events of the Duck Flats at the eastern end of the Knik Arm, Alaska

    NASA Astrophysics Data System (ADS)

    Reeder, J. W.

    2012-12-01

    A 5 km NS-trending gas pipeline trench, excavated in 1984 across the Duck Flats of the eastern end of the Knik Arm about 50 km NE of Anchorage, Alaska, exposed two continuous buried peat horizons. Two bulk C-14 dates for the upper buried peat horizon were determined to be 790 ± 160 and 775 ± 170 ybp. The depth of this peat horizon varied from 1.0 to 1.8 m. The deeper paleopeat horizon had a single bulk C-14 date of 1190 ± 80 ybp and varied from 1.7 to greater than 2.4 m (depth of trench). A deeper third paleopeat horizon was confirmed in 2012 by hand auger, which was found at a depth of 3.7 m. Turbulent organic (principally grass) mixing with tidal silt and clay immediately above both of the trench paleopeat horizons is interpreted to reflect tsunami flooding. The March 27, 1964, earthquake caused recognized subsidence of up to 0.3 m at the southern end of the trench as based on tidal deposits above 1964 peats. This was caused by consolidation of Matanuska and Knik fluvial deposits immediately to the S and by some tectonic subsidence. The 1964 peat horizon was not recognized for the rest of the trench possibly because of poor near-surface winter exposures or more simply because the 1964 peat horizon is also part of the present surface. The existence of the above continuous paleopeat horizons is significant because they reflect subsidence events not expected with 1964-type megathrust subduction. In fact, the above paleopeat C-14 age dates correlate more with recognized earthquake events of the Castle Mountain fault, an intraplate fault 20 km to the NW, than with recognized 1964-type megathrust events. However, movements on regional crustal faults, such as the Castle Mountain fault, likely would not be enough to account for the large amounts of subsidence observed on the Duck Flats. Instead, these subsidence events probably reflect sudden tectonic movements of the Pacific plate beneath the North American plate in this region. The process would involve flat

  1. Significance chasing in research practice: Causes, consequences, and possible solutions

    PubMed Central

    Ware, Jennifer J.; Munafò, Marcus R.

    2016-01-01

    Background and Aims The low reproducibility of findings within the scientific literature is a growing concern. This may be due to many findings being false positives, which in turn can misdirect research effort and waste money. Methods We review factors that may contribute to poor study reproducibility and an excess of ‘significant’ findings within the published literature. Specifically, we consider the influence of current incentive structures, and the impact of these on research practices. Results The prevalence of false positives within the literature may be attributable to a number of questionable research practices, ranging from the relatively innocent and minor (e.g., unplanned post hoc tests), to the calculated and serious (e.g., fabrication of data). These practices may be driven by current incentive structures (e.g. pressure to publish), alongside the preferential emphasis placed by journals on novelty over veracity. There are a number of potential solutions to poor reproducibility, such as new publishing formats that emphasise the research question and study design, rather than the results obtained. This has the potential to minimise significance chasing and non-publication of null findings. Conclusions Significance chasing, questionable research practices, and poor study reproducibility are the unfortunate consequence of a “publish or perish” culture and a preference among journals for novel findings. It is likely that top-down change implemented by those with the ability to modify current incentive structure (e.g., funders and journals) will be required to address problems of poor reproducibility. PMID:25040652

  2. Insights from interviews regarding high fatality rate caused by the 2011 Tohoku-Oki earthquake

    NASA Astrophysics Data System (ADS)

    Ando, M.; Ishida, M.

    2012-12-01

    The 11 March 2011 Tohoku-Oki earthquake (Mw9.0) caused approximately 19,000 casualties including missing persons along the entire coast of the Tohoku region. Three historical tsunamis occurred in the past 115 years preceding this tsunami. Since these tsunamis, numerous countermeasures against future tsunamis such as breakwaters, early tsunami warning systems and tsunami evacuation drills were implemented. Despite the preparedness, a number of deaths and missing persons occurred. Although this death rate is approximately 4 % of the population in severely inundated areas; 96 % safely evacuated or managed to survive the tsunami. To understand why some people evacuated immediately while others delayed; survivors were interviewed in the northern part of the Tohoku region. Our interviews revealed that many residents obtained no appropriate warnings and many chose to remain in dangerous locations partly because they obtained the wrong idea of the risks. In addition, our interviews also indicated that the resultant high casualties were due to current technology malfunction, underestimated earthquake size and tsunami heights, and failure of warning systems. Furthermore, the existing breakwaters provided the local community a false sense of security. The advanced technology did not work properly, especially at the time of the severe disaster. If residents had taken an immediate action after the major shaking stopped, most local residents might have survived considering that safer highlands are within 5 to 20 minute walking distance from the interviewed areas. However, the elderly and physically disabled people would still be in a much more difficult situation to walk such distance into safety. Nevertheless, even if these problems occur in future earthquakes, better knowledge regarding earthquakes and tsunami hazards could save more lives. People must take immediate action without waiting for official warning or help. To avoid similar high tsunami death ratios in the future

  3. 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.

  4. Temporal Changes in Stress Drop, Frictional Strength, and Earthquake Size Distribution in the 2011 Yamagata-Fukushima, NE Japan, Earthquake Swarm, Caused by Fluid Migration

    NASA Astrophysics Data System (ADS)

    Yoshida, Keisuke; Saito, Tatsuhiko; Urata, Yumi; Asano, Youichi; Hasegawa, Akira

    2017-12-01

    In this study, we investigated temporal variations in stress drop and b-value in the earthquake swarm that occurred at the Yamagata-Fukushima border, NE Japan, after the 2011 Tohoku-Oki earthquake. In this swarm, frictional strengths were estimated to have changed with time due to fluid diffusion. We first estimated the source spectra for 1,800 earthquakes with 2.0 ≤ MJMA < 3.0, by correcting the site-amplification and attenuation effects determined using both S waves and coda waves. We then determined corner frequency assuming the omega-square model and estimated stress drop for 1,693 earthquakes. We found that the estimated stress drops tended to have values of 1-4 MPa and that stress drops significantly changed with time. In particular, the estimated stress drops were very small at the beginning, and increased with time for 50 days. Similar temporal changes were obtained for b-value; the b-value was very high (b 2) at the beginning, and decreased with time, becoming approximately constant (b 1) after 50 days. Patterns of temporal changes in stress drop and b-value were similar to the patterns for frictional strength and earthquake occurrence rate, suggesting that the change in frictional strength due to migrating fluid not only triggered the swarm activity but also affected earthquake and seismicity characteristics. The estimated high Q-1 value, as well as the hypocenter migration, supports the presence of fluid, and its role in the generation and physical characteristics of the swarm.

  5. Earthquake-caused coastal uplift and its effects on rocky intertidal kelp communities.

    PubMed

    Castilla, J C

    1988-10-21

    The coastal uplift(approximately 40 to 60 centimeters) associated with the Chilean earthquake of 3 March 1985 caused extensive mortality of intertidal organisms at the Estación Costera de Investigaciones Marinas, Las Cruces. The kelp belt of the laminarian Lessonia nigrescens was particularly affected. Most of the primary space liberated at the upper border of this belt was invaded by species of barnacles, which showed an opportunistic colonization strategy. Drastic modifications in the environment such as coastal uplift, subsidence, or the effects of the El Niño phenomenon are characteristic of the southern Pacific. Modifications in the marine ecosystem that generate catastrophic and widespread mortalities of intertidal organisms can affect species composition, diversity, or local biogeography.

  6. Bermuda earthquake of March 24, 1978: A significant oceanic intraplate event

    SciTech Connect

    Stewart, G.S.; Helmberger, D.V.

    1981-08-10

    The Bremuda earthquake (Mapprox.6) occured near the westerly extension of the Kane Fracture Zone roughly 370 km southwest of the island of Bermuda. It is one of the largest oceanic intraplate earthquakes to occur off the eastern coast of North America. Because of its size and location, it has provided an excellent set of WWSSN body waves. They can be used to infer its depth and faulting parameters by waveform modeling techniques. The results indicate a north-northwest striking thrust mechanism (strike = N20 /sup 0/W, dip = 42 /sup 0/NE, rake = 90/sup 0/) with the hypocenter located at amore » depth of 11 km, which for an oceanic crust places it predominantly in the mantle. The event had a seismic moment of 3.4 x 10/sup 25/ dyne cm, and its time history was modeled with a symmetric trapezoidal time function 3 s in duration. The north-northwest strike of the event is in good agreement with the bathymetry of the area, the epicenter being close to the southwestern edge of the Bermuda Rise. The strike of the event is also close to that of the inferred extensions of the present ridge fracture zones in the region. The strike of the event is also close to that of the inferred extensions of the present ridge fracture zones in the region. The presence of fracture zones is indicative of local weak zones in the lithosphere. The Bermuda earthquake most likely is associated with one of these zones of weakness and is the result of the application of present day stress imposed on the region by the North American plate in the direction of its absolute motion. This is an important event in terms of understanding and estimating seismic hazard on the eastern seaboard of North America.« less

  7. 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.

  8. Did stress triggering cause the large off-fault aftershocks of the 25 March 1998 MW=8.1 Antarctic plate earthquake?

    USGS Publications Warehouse

    Toda, S.; Stein, R.S.

    2000-01-01

    The 1998 Antarctic plate earthquake produced clusters of aftershocks (MW ??? 6.4) up to 80 km from the fault rupture and up to 100 km beyond the end of the rupture. Because the mainshock occurred far from the nearest plate boundary and the nearest recorded earthquake, it is unusually isolated from the stress perturbations caused by other earthquakes, making it a good candidate for stress transfer analysis despite the absence of near-field observations. We tested whether the off-fault aftershocks lie in regions brought closer to Coulomb failure by the main rupture. We evaluated four published source models for the main rupture. In fourteen tests using different aftershocks sets and allowing the rupture sources to be shifted within their uncertainties, 6 were significant at ??? 99% confidence, 3 at > 95% confidence, and 5 were not significant (< 95% level). For the 9 successful tests, the stress at the site of the aftershocks was typically increased by 1-2 bars (0.1-0.2 MPa). Thus the Antarctic plate event, together with the 1992 MW=7.3 Landers and its MW=6.5 Big Bear aftershock 40 km from the main fault, supply evidence that small stress changes might indeed trigger large earthquakes far from the main fault rupture.

  9. Simulation of earthquake caused building damages for the development of fast reconnaissance techniques

    NASA Astrophysics Data System (ADS)

    Schweier, C.; Markus, M.; Steinle, E.

    2004-04-01

    Catastrophic events like strong earthquakes can cause big losses in life and economic values. An increase in the efficiency of reconnaissance techniques could help to reduce the losses in life as many victims die after and not during the event. A basic prerequisite to improve the rescue teams' work is an improved planning of the measures. This can only be done on the basis of reliable and detailed information about the actual situation in the affected regions. Therefore, a bundle of projects at Karlsruhe university aim at the development of a tool for fast information retrieval after strong earthquakes. The focus is on urban areas as the most losses occur there. In this paper the approach for a damage analysis of buildings will be presented. It consists of an automatic methodology to model buildings in three dimensions, a comparison of pre- and post-event models to detect changes and a subsequent classification of the changes into damage types. The process is based on information extraction from airborne laserscanning data, i.e. digital surface models (DSM) acquired through scanning of an area with pulsed laser light. To date, there are no laserscanning derived DSMs available to the authors that were taken of areas that suffered damages from earthquakes. Therefore, it was necessary to simulate such data for the development of the damage detection methodology. In this paper two different methodologies used for simulating the data will be presented. The first method is to create CAD models of undamaged buildings based on their construction plans and alter them artificially in such a way as if they had suffered serious damage. Then, a laserscanning data set is simulated based on these models which can be compared with real laserscanning data acquired of the buildings (in intact state). The other approach is to use measurements of actual damaged buildings and simulate their intact state. It is possible to model the geometrical structure of these damaged buildings based

  10. 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. 

  11. The determination of interseismic, coseismic and postseismic deformations caused by the Gökçeada-Samothraki earthquake (2014, Mw: 6.9) based on GNSS data

    NASA Astrophysics Data System (ADS)

    Tiryakioglu, Ibrahim; Yigit, Cemal Ozer; Yavasoglu, Hakan; Saka, Mehmet Halis; Alkan, Reha Metin

    2017-09-01

    Since the 1990s, seismic deformations have been commonly determined using the Global Navigation Satellite System (GNSS). Recently, the GNSS systems have become even more powerful with the use of new technologies in innovative studies. In this study, the GNSS data was used to investigate interseismic, coseismic and postseismic deformation and velocity of the Gökçeada-Samothraki earthquake (Mw = 6.9) that occurred on May 24, 2014. The data was obtained at 30 s (0.033 Hz) and 1 s (1 Hz) intervals from the GNSS receivers in the network of Continuously Operating Reference Stations, Turkey (CORS-TR). For the interseismic period, the daily coordinate time series of 12 stations located within 90-250 km of the earthquake epicenter was evaluated for the displacement of stations over a period of approximately 2000 days prior to the day of the earthquakes, from October 1, 2008 to May 23, 2014. In order to analyze the ground motion displacement during the Gökçeada-Samothraki earthquake, 1 Hz data from 8 continuous GNSS stations was processed using precise point positioning (PPP) and relative positioning methods to estimate the epoch-by-epoch positions of the stations. During the earthquake, coseismic displacements of approximately 7 and 30 mm were detected in the NW direction at the YENC and CANA stations, respectively. However, at the IPSA station, a coseismic deformation of 20 mm was observed in the NE direction. There were no significant changes at the other stations during the earthquake. For the postseismic period, the daily coordinate time series of the 12 stations were evaluated for station displacements for 570 days after the day of the earthquakes, from May 24, 2014 to January 1, 2016. The results demonstrated that no significant postseismic deformation with the exception of the EDIR station. An abnormal deformation caused by local factors was determined at the EDIR station. In this study, the PPP and the relative solution were also compared in terms of capturing

  12. Earthquake prognosis:cause for failure and ways for the problem solution

    NASA Astrophysics Data System (ADS)

    Kondratiev, O.

    2003-04-01

    Despite of the more than 50-years history of the development of the prognosis earthquake method this problem is yet not to be resolved. This makes one to have doubt in rightness of the chosen approaches retrospective search of the diverse earthquake precursors. It is obvious to speak of long-term, middle-term and short-term earthquake prognosis. They all have a probabilistic character and it would be more correct to consider them as related to the seismic hazard prognosis. In distinction of them, the problem of the operative prognosis is being discussed in report. The operative prognosis should conclude the opportune presenting of the seismic alarm signal of the place, time and power of the earthquake in order to take necessary measures for maximal mitigation of the catastrophic consequence of this event. To do this it is necessary to predict the earthquake location with accuracy of first dozens of kilometres, time of its occurrence with accuracy of the first days and its power with accuracy of the magnitude units. If the problem is formulated in such a way, it cannot principally be resolved in the framework of the concept of the indirect earthquake precursors using. It is necessary to pass from the concept of the passive observatory network to the concept of the object-oriented search of the potential source zones and direct information obtaining on the parameter medium changes within these zones in the process of the earthquake preparation and development. While formulated in this way, the problem becomes a integrated task for the planet and prospecting geophysics. To detect the source zones it is possible to use the method of the converted waves of earthquakes, for monitoring - seismic reflecting and method of the common point. Arrangement of these and possible other geophysical methods should be provided by organising the special integrated geophysic expedition of the rapid response on the occurred strong earthquakes and conducting purposeful investigation

  13. Surface deformation associated with the 2013 Mw7.7 Balochistan earthquake: Geologic slip rates may significantly underestimate strain release

    NASA Astrophysics Data System (ADS)

    Gold, Ryan; Reitman, Nadine; Briggs, Richard; Barnhart, William; Hayes, Gavin

    2015-04-01

    The 24 September 2013 Mw7.7 Balochistan, Pakistan earthquake ruptured a ~200 km-long stretch of the 60° ± 15° northwest-dipping Hoshab fault in southern Pakistan. The earthquake is notable because it produced the second-largest lateral surface displacement observed for a continental strike-slip earthquake. Surface displacements and geodetic and teleseismic inversions indicate that peak slip occurred within the upper 0-3 km of the crust. To explore along-strike and fault-perpendicular surface deformation patterns, we remotely mapped the surface trace of the rupture and measured its surface deformation using high-resolution (0.5 m) pre- and post-event satellite imagery. Post-event images were collected 7-114 days following the earthquake, so our analysis captures the sum of both the coseismic and post-seismic (e.g., after slip) deformation. We document peak left-lateral offset of ~15 m using 289 near-field (±10 m from fault) laterally offset piercing points, such as streams, terrace risers, and roads. We characterize off-fault deformation by measuring the medium- (±200 m from fault) and far-field (±10 km from fault) displacement using manual (242 measurements) and automated image cross-correlation methods. Off-fault peak lateral displacement values (medium- and far-field) are ~16 m and commonly exceed the on-fault displacement magnitudes. Our observations suggest that coseismic surface displacement typically increases with distance away from the surface trace of the fault; however, the majority of surface displacement is within 100 m of the primary fault trace and is most localized on sections of the rupture exhibiting narrow (<5 m) zones of observable surface deformation. Furthermore, the near-field displacement measurements account for, on average, only 73% of the total coseismic displacement field and the pattern is highly heterogeneous. This analysis highlights the importance of identifying paleoseismic field study sites (e.g. trenches) that span fault

  14. New contributions to the debate on the cause of the January 11th, 1693 tsunami in eastern Sicily (Italy): earthquake or offshore landslide source (or may be both)?

    NASA Astrophysics Data System (ADS)

    Armigliato, A.; Tinti, S.; Zaniboni, F.; Pagnoni, G.; Argnani, A.

    2007-12-01

    Eastern Sicily is among the most exposed regions in Italy and in the whole Mediterranean to tsunami hazard and risk. The historical tsunamis recorded here were generally associated to moderate-to-large magnitude earthquakes. The largest tsunami documented in the area occurred on January 11th, 1693. It followed the highest-magnitude earthquake (7.4) of the Italian seismic history. The tsunami, whose first significant motion was a retreat along the entire eastern Sicily coastline, produced the most devastating effects at Augusta (15 meters run-up) and Catania, being relevant at Siracusa and Messina too. A lively debate exists on whether the earthquake was the only source of the tsunami, or other causes (such as submarine landslides, possibly triggered by the earthquake) contributed to the tsunami generation. In the framework of the EC funded project TRANSFER, we investigate both hypotheses, starting from suitable onshore and offshore faults as well as from offshore landslide bodies, and hence simulating numerically the ensuing tsunami and comparing the results with the available historical information. We base on the results obtained during recent offshore surveys, in particular the multichannel seismic survey MESC2001, carried out in year 2001 on board the R/V Urania of the Italian National Council of Researches (CNR), which mapped both active normal faults and a number of possible landslide bodies along the Hyblaean-Malta escarpment, the most prominent tectonic structure found just few kilometres offshore eastern Sicily. From the modelling point of view, the initial condition for the earthquake- generated tsunamis coincides with the vertical coseismic deformation of the seafloor. Instead, the landslide motion is simulated through the Lagrangian block model UBO-BLOCK2, developed at the University of Bologna. Finally, the finite-element code UBO-TSUFE, implemented by the same research team, is used to simulate the tsunami generation and propagation. The main

  15. Study of the structure changes caused by earthquakes in Chile applying the lineament analysis to the Aster (Terra) satellite data.

    NASA Astrophysics Data System (ADS)

    Arellano-Baeza, A.; Zverev, A.; Malinnikov, V.

    Chile is one of the most seismically and volcanically active regions in the South America due to a constant subdiction of the South American plate, converging with the Nazca plate in the extreme North of Chile. Four events, namely: the Ovalle earthquake of Juny 18, 2003, M=6.3, with epicenter localized at (-30:49:33, -71:18:53), the Calama earthquake of Junly 19, 2001, M=5.2, (-30:29:38,-68:33:18), the Pica earthquake of April 10, 2003, M=5.1, (-21:03:20,-68:47:10) and the La Ligua earthquake of May 6, 2001, M=5.1, (-32:35:31,-71:07:58:) were analysed using the 15 m resolution satellite images, provided by the ASTER/VNIR instrument. The Lineament Extraction and Stripes Statistic Analysis (LESSA) software package was used to examine changes in the lineament features caused by sismic activity. Lack of vegetation facilitates the study of the changes in the topography common to all events and makes it possible to evaluate the sismic risk in this region for the future.

  16. Landslide maps and seismic noise: Rockmass weakening caused by shallow earthquakes

    NASA Astrophysics Data System (ADS)

    Uchida, Tara; Marc, Odin; Sens-Schönfelder, Christoph; Sawazaki, Kaoru; Hobiger, Manuel; Hovius, Niels

    2015-04-01

    Some studies have suggested that the shaking and deformation associated with earthquake would result in a temporary increased hillslope erodibility. However very few data have been able to clarify such effect. We present integrated geomorphic data constraining an elevated landslide rate following 4 continental shallow earthquakes, the Mw 6.9 Finisterre (1993), the Mw 7.6 ChiChi (1999), the Mw 6.6 Niigata (2004) and the Mw 6.8 Iwate-Miyagi (2008) earthquakes. We constrained the magnitude, the recovery time and somewhat the mechanism at the source of this higher landslide risk. We provide some evidences excluding aftershocks or rain forcing intensity as possible mechanism and leaving subsurface weakening as the most likely. The landslide data suggest that this ground strength weakening is not limited to the soil cover but also affect the shallow bedrock. Additionally, we used ambient noise autocorrelation techniques to monitor shallow subsurface seismic velocity within the epicentral area of three of those earthquakes. For most stations we observe a velocity drop followed by a recovery processes of several years in fair agreement with the recovery time estimated based on landslide observation. Thus a common processes could alter the strength of the first 10m of soil/rock and simultaneously drive the landslide rate increase and the seismic velocity drop. The ability to firmly demonstrate this link require additional constraints on the seismic signal interpretation but would provide a very useful tool for post-earthquake risk managment.

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

    USGS Publications Warehouse

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

    2015-01-01

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

  18. Waveform complexity caused by near trench structure and its impact on earthquake source study: application to the 2015 Illapel earthquake sequence

    NASA Astrophysics Data System (ADS)

    Qian, Y.; Wei, S.; Wu, W.; Ni, S.

    2017-12-01

    Among various types of 3D heterogeneity in the Earth, trench might be the most complex systems, which includes rapidly varying bathymetry and usually thick sediment below water layer. These structure complexities can cause substantial waveform complexities on seismograms, but their corresponding impact on the earthquake source studies has not yet been well understood. Here we explore those effects via studies of two moderate aftershocks (one near the coast while the other close to the Peru-Chile trench axis) in the 2015 Illapel earthquake sequence. The horizontal locations and depths of these two events are poorly constrained and the reported results of various agencies display substantial variations. Thus, we first relocated the epicenters using the P-wave first arrivals and determined other parameters by waveform fitting. In a jackknifing way, we found that the trench event has large differences between regional and teleseismic solutions, in particular for depth, while the coastal event shows consistent results. The teleseismic P/Pdiff waves between these two events also display distinctly different features. More specifically, the trench event has more complex P/Pdiff waves and stronger coda waves, in terms of amplitude and duration (longer than 100s). The coda waves are coherent across stations at different distances and azimuths, indicating a more likely origin of scattering waves due to 3D heterogeneity near trench. To quantitatively model those 3D effects, we adopted a hybrid waveform simulation approach that computes the 3D wavefield in the source region by the Spectral Element Method (SEM) and then propagates the wavefield to teleseismic and shadow zone distances through the Direct Solution Method (DSM). We incorporated the GEBCO bathymetry and water layer into the SEM simulations and assumed the IASP91 1D model for DSM computation. Comparing with the poor 1D synthetics fitting to the data, we do obtain dramatic improvement in 3D waveform fittings across a

  19. Field Observations of Precursors to Large Earthquakes: Interpreting and Verifying Their Causes

    NASA Astrophysics Data System (ADS)

    Suyehiro, K.; Sacks, S. I.; Rydelek, P. A.; Smith, D. E.; Takanami, T.

    2017-12-01

    Many reports of precursory anomalies before large earthquakes exist. However, it has proven elusive to even identify these signals before their actual occurrences. They often only become evident in retrospect. A probabilistic cellular automaton model (Sacks and Rydelek, 1995) explains many of the statistical and dynamic natures of earthquakes including the observed b-value decrease towards a large earthquake or a small stress perturbation to have effect on earthquake occurrence pattern. It also reproduces dynamic characters of each earthquake rupture. This model is useful in gaining insights on causal relationship behind complexities. For example, some reported cases of background seismicity quiescence before a main shock only seen for events larger than M=3 4 at years time scale can be reproduced by this model, if only a small fraction ( 2%) of the component cells are strengthened by a small amount. Such an enhancement may physically occur if a tiny and scattered portion of the seismogenic crust undergoes dilatancy hardening. Such a process to occur will be dependent on the fluid migration and microcracks developments under tectonic loading. Eventual large earthquake faulting will be promoted by the intrusion of excess water from surrounding rocks into the zone capable of cascading slips to a large area. We propose this process manifests itself on the surface as hydrologic, geochemical, or macroscopic anomalies, for which so many reports exist. We infer from seismicity that the eastern Nankai Trough (Tokai) area of central Japan is already in the stage of M-dependent seismic quiescence. Therefore, we advocate that new observations sensitive to detecting water migration in Tokai should be implemented. In particular, vertical component strain, gravity, and/or electrical conductivity, should be observed for verification.

  20. Tracking Down the Causes of Recent Induced and Natural Intraplate Earthquakes with 3D Seismological Analyses in Northwest Germany

    NASA Astrophysics Data System (ADS)

    Uta, P.; Brandes, C.; Boennemann, C.; Plenefisch, T.; Winsemann, J.

    2015-12-01

    Northwest Germany is a typical low strain intraplate region with a low seismic activity. Nevertheless, 58 well documented earthquakes with magnitudes of 0.5 - 4.3 affected the area in the last 40 years. Most of the epicenters were located in the vicinity of active natural gas fields and some inside. Accordingly, the earthquakes were interpreted as a consequence of hydrocarbon recovery (e.g. Dahm et al. 2007, Bischoff et al. 2013) and classified as induced events in the bulletins of the Federal Institute for Geosciences and Natural Resources (BGR). The two major ones have magnitudes of 4.3 and 4.0. They are the strongest earthquakes ever recorded in Northern Germany. Consequently, these events raise the question whether the ongoing extraction itself can cause them or if other natural tectonic processes like glacial isostatic adjustment may considerably contribute to their initiation. Recent studies of Brandes et al. (2012) imply that lithospheric stress changes due to post glacial isostatic adjustment might be also a potential natural cause for earthquakes in Central Europe. In order to better analyse the earthquakes and to test this latter hypothesis we performed a relocalization of the events with the NonLinLoc (Lomax et al. 2000) program package and two differently scaled 3D P-wave velocity models. Depending on the station coverage for a distinct event, either a fine gridded local model (88 x 73 x 15 km, WEG-model, made available by the industry) or a coarse regional model (1600 x 1600 x 45 km, data from CRUST1.0, Laske et al. 2013) and for some cases a combination of both models was used for the relocalization. The results confirm the trend of the older routine analysis: The majority of the events are located at the margins of the natural gas fields, some of them are now located closer to them. Focal depths mostly vary between 3.5 km and 10 km. However, for some of the events, especially for the older events with relatively bad station coverage, the error bars

  1. Sources of Increased Spring and Streamflow Caused by the 2014 South Napa Earthquake

    NASA Astrophysics Data System (ADS)

    Rytuba, J. J.; Holzer, T. L.

    2014-12-01

    Seasonally dry springs and creeks began flowing over a broad region in the hills around Napa following the M6.0 South Napa earthquake on August 24, 2014. Flows in hillside creek beds, which were dry before the earthquake, were reported from 19 km west, to 6 km east, and 18 km north of Napa and the epicenter, an area that shook at MMI≥VI. The exact timing of the increased flow is unknown because the earthquake occurred at 3:20 AM PDT. A gaging station on the Napa River, which is downstream from several tributaries that began flowing after the earthquake, showed a sudden increase of flow rate within 45 minutes following the earthquake. The sudden increase at the gaging station suggests flows initiated either contemporaneously with or very soon after the strong shaking. This timing is consistent with eyewitness accounts of other streams and springs at daylight, a few hours after the earthquake. One of the largest increases of streamflow was in Green Valley, where a streamflow rate of about 100 cubic hectometers per day was measured in Wild Horse Creek. Two types of waters are being discharged in the Wild Horse Creek drainage: 1) water with low iron concentration that has exchanged with rhyolitic flows and tuffs in the upper part of the drainage; and 2) high iron concentration water that has exchanged with basaltic andesite in the middle part of drainage (vertical interval of about 75 meters). The high iron waters are depositing FeOOH other iron phases. Mixing of the two water types results in water with pH 6.9 and conductivity of 0.197 mS. This water is used by the Vallejo Water District for domestic purposes after it is mixed with recent surface water runoff stored in Lake Frey reservoir in order to improve its quality. Other drainages that have increased flow since the earthquake have water chemistry consistent with exchange with rhyolitic flows and tuffs that are the dominant rock type in these drainages.

  2. Change in failure stress on the southern San Andreas fault system caused by the 1992 magnitude = 7.4 Landers earthquake

    USGS Publications Warehouse

    Stein, R.S.; King, G.C.P.; Lin, J.

    1992-01-01

    The 28 June Landers earthquake brought the San Andreas fault significantly closer to failure near San Bernardino, a site that has not sustained a large shock since 1812. Stress also increased on the San Jacinto fault near San Bernardino and on the San Andreas fault southeast of Palm Springs. Unless creep or moderate earthquakes relieve these stress changes, the next great earthquake on the southern San Andreas fault is likely to be advanced by one to two decades. In contrast, stress on the San Andreas north of Los Angeles dropped, potentially delaying the next great earthquake there by 2 to 10 years.

  3. Mapping three-dimensional surface deformation caused by the 2010 Haiti earthquake using advanced satellite radar interferometry.

    PubMed

    Jung, Hyung-Sup; Hong, Soo-Min

    2017-01-01

    Mapping three-dimensional (3D) surface deformation caused by an earthquake is very important for the environmental, cultural, economic and social sustainability of human beings. Synthetic aperture radar (SAR) systems made it possible to measure precise 3D deformations by combining SAR interferometry (InSAR) and multiple aperture interferometry (MAI). In this paper, we retrieve the 3D surface deformation field of the 2010 Haiti earthquake which occurred on January 12, 2010 by a magnitude 7.0 Mw by using the advanced interferometric technique that integrates InSAR and MAI data. The surface deformation has been observed by previous researchers using the InSAR and GPS method, but 3D deformation has not been measured yet due to low interferometric coherence. The combination of InSAR and MAI were applied to the ALOS PALSAR ascending and descending pairs, and were validated with the GPS in-situ measurements. The archived measurement accuracy was as little as 1.85, 5.49 and 3.08 cm in the east, north and up directions, respectively. This result indicates that the InSAR/MAI-derived 3D deformations are well matched with the GPS deformations. The 3D deformations are expected to allow us to improve estimation of the area affected by the 2010 Haiti earthquake.

  4. Mapping three-dimensional surface deformation caused by the 2010 Haiti earthquake using advanced satellite radar interferometry

    PubMed Central

    Jung, Hyung-Sup; Hong, Soo-Min

    2017-01-01

    Mapping three-dimensional (3D) surface deformation caused by an earthquake is very important for the environmental, cultural, economic and social sustainability of human beings. Synthetic aperture radar (SAR) systems made it possible to measure precise 3D deformations by combining SAR interferometry (InSAR) and multiple aperture interferometry (MAI). In this paper, we retrieve the 3D surface deformation field of the 2010 Haiti earthquake which occurred on January 12, 2010 by a magnitude 7.0 Mw by using the advanced interferometric technique that integrates InSAR and MAI data. The surface deformation has been observed by previous researchers using the InSAR and GPS method, but 3D deformation has not been measured yet due to low interferometric coherence. The combination of InSAR and MAI were applied to the ALOS PALSAR ascending and descending pairs, and were validated with the GPS in-situ measurements. The archived measurement accuracy was as little as 1.85, 5.49 and 3.08 cm in the east, north and up directions, respectively. This result indicates that the InSAR/MAI-derived 3D deformations are well matched with the GPS deformations. The 3D deformations are expected to allow us to improve estimation of the area affected by the 2010 Haiti earthquake. PMID:29145475

  5. Causes of earthquake spatial distribution beneath the Izu-Bonin-Mariana Arc

    NASA Astrophysics Data System (ADS)

    Kong, Xiangchao; Li, Sanzhong; Wang, Yongming; Suo, Yanhui; Dai, Liming; Géli, Louis; Zhang, Yong; Guo, Lingli; Wang, Pengcheng

    2018-01-01

    Statistics about the occurrence frequency of earthquakes (1973-2015) at shallow, intermediate and great depths along the Izu-Bonin-Mariana (IBM) Arc is presented and a percent perturbation relative to P-wave mean value (LLNL-G3Dv3) is adopted to show the deep structure. The correlation coefficient between the subduction rate and the frequency of shallow seismic events along the IBM is 0.605, proving that the subduction rate is an important factor for shallow seismic events. The relationship between relief amplitudes of the seafloor and earthquake occurrences implies that some seamount chains riding on the Pacific seafloor may have an effect on intermediate-depth seismic events along the IBM. A probable hypothesis is proposed that the seamounts or surrounding seafloor with high degree of fracture may bring numerous hydrous minerals into the deep and may result in a different thermal structure compared to the seafloor where no seamounts are subducted. Fluids from the seamounts or surrounding seafloor are released to trigger earthquakes at intermediate-depth. Deep events in the northern and southern Mariana arc are likely affected by a horizontal propagating tear parallel to the trench.

  6. Does Geothermal Energy Production Cause Earthquakes in the Geysers Region of Northern California?

    NASA Astrophysics Data System (ADS)

    Grove, K.; Bailey, C.; Sotto, M.; Yu, M.; Cohen, M.

    2003-12-01

    The Geysers region is located in Sonoma County, several hours north of San Francisco. At this location, hot magma beneath the surface heats ground water and creates steam that is used to make electricity. Since 1997, 8 billion gallons of treated wastewater have been injected into the ground, where the water becomes hot and increases the amount of thermal energy that can be produced. Frequent micro-earthquakes (up to magnitude 4.5) occur in the region and seem to be related to the geothermal energy production. The region is mostly uninhabited, except for several small towns such as Anderson Springs, where people have been extremely concerned about potential damage to their property. The energy companies are planning to double the amount of wastewater injected into the ground and to increase their energy production. Geothermal energy is important because it is better for the environment than burning coal, oil, or gas. Air and water pollution, which have negative impacts on living things, are reduced compared to power plants that generate electricity by burning fossil fuels. We have studied the frequency and magnitude of earthquakes that have occurred in the region since the early 1970s and that are occurring today. We used software to analyze the earthquakes and to look for patterns related to water injection and energy production. We are interested in exploring ways that energy production can be continued without having negative impacts on the people in the region.

  7. The HayWired Earthquake Scenario—Earthquake Hazards

    USGS Publications Warehouse

    Detweiler, Shane T.; Wein, Anne M.

    2017-04-24

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

  8. Strong ground motion inferred from liquefaction caused by the 1811-1812 New Madrid, Missouri, earthquakes

    USGS Publications Warehouse

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

    2015-01-01

    Peak ground accelerations (PGAs) in the epicentral region of the 1811–1812 New Madrid, Missouri, earthquakes are inferred from liquefaction to have been no greater than ∼0.35g. PGA is inferred in an 11,380  km2 area in the Lower Mississippi Valley in Arkansas and Missouri where liquefaction was extensive in 1811–1812. PGA was inferred by applying liquefaction probability curves, which were originally developed for liquefaction hazard mapping, to detailed maps of liquefaction by Obermeier (1989). The low PGA is inferred because both a shallow (1.5 m deep) water table and a large moment magnitude (M 7.7) earthquake were assumed in the analysis. If a deep (5.0 m) water table and a small magnitude (M 6.8) earthquake are assumed, the maximum inferred PGA is 1.10g. Both inferred PGA values are based on an assumed and poorly constrained correction for sand aging. If an aging correction is not assumed, then the inferred PGA is no greater than 0.22g. A low PGA value may be explained by nonlinear site response. Soils in the study area have an averageVS30 of 220±15  m/s. A low inferred PGA is consistent with PGA values estimated from ground‐motion prediction equations that have been proposed for the New Madrid seismic zone when these estimates are corrected for nonlinear soil site effects. This application of liquefaction probability curves demonstrates their potential usefulness in paleoseismology.

  9. Widespread groundwater-level offsets caused by the Mw 5.8 Mineral, Virginia, earthquake of 23 August 2011

    USGS Publications Warehouse

    Roeloffs, Evelyn A.; Nelms, David L.; Sheets, Rodney A.

    2015-01-01

    Groundwater levels were offset in bedrock observation wells, measured by the U.S. Geological Survey or others, as far as 553 km from the Mw 5.8 Mineral, Virginia (USA), earthquake on 23 August 2011. Water levels dropped as much as 0.47 m in 34 wells and rose as much as 0.15 m in 12 others. In some wells, which are as much as 213 m deep, the water levels recovered from these deviations in hours to days, but in others the water-level offset may have persisted. The groundwater-level offsets occurred in locations where the earthquake was at least weakly felt, and the maximum water-level excursion increased with felt intensity, independent of epicentral distance. Coseismic static strain from the earthquake was too small and localized to have contributed significantly to the groundwater-level offsets. The relation with intensity is consistent with ground motion from seismic waves leading to the water-level offsets. Examination of the hydrographs indicates that short-period ground motion most likely affected the permeability of the bedrock aquifers monitored by the wells.

  10. Earthquake statistics, spatiotemporal distribution of foci and source mechanisms as a key to understanding of causes leading to the West Bohemia/Vogtland earthquake swarms

    NASA Astrophysics Data System (ADS)

    Horalek, Josef; Jakoubkova, Hana

    2017-04-01

    The origin of earthquake swarms is still unclear. The swarms typically occur at the plate margins but also in intracontinental areas. West Bohemia-Vogtland represents one of the most active intraplate earthquake-swarm areas in Europe. It is characterised by a frequent reoccurrence of ML < 4.0 swarms and by high activity of crustal fluids. The Nový Kostel focal zone (NK) dominates the recent seismicity of the whole region. There were swarms in 1997, 2000, 2008 and 20011 followed by reactivation in 2013 which forming a focal belt of about 15 x 6 km, focal depths vary from 6 to 15 km. An exceptional non-swarm activity (mainshock-aftershock sequences) up to magnitudes ML = 4.5, stroke the region in May to August 2014, the events were also located in the NK swarm-focal belt. We analysed geometry of the NK focal zone applying the double-difference method to seismicity in the period 1997 - 2014. The swarms are located close to each other at depths between 6 and 13 km, the 2014 maishock-aftershock sequences among them. The 2000 and 2008 swarms were located on the same portion of the NK fault, similarly the swarms of 1997, 2011 and 2013 also occurred on the same fault segment. Other fault segment hosted three mainshock-aftershock sequences of 2014. The individual swarms differ considerably in their evolution, mainly in the rate of the seismic-moment release and foci migration. The frequency-magnitude distributions of all the swarms show bimodal-like character: the most events obey the b-value = 1.0 distribution, however, a group of the largest events ( ML > 2.8) depart significantly from it. Furthermore, we disclose that all the ML > 2.8 swarm events, which occurred in the given time span, are located in a few dense clusters. It implies that the most of seismic energy in the individual swarms has been released in step by step rupturing of one or a few asperities. The source mechanisms have been retrieved in the full moment-tensor description (MT). The mechanism patters of

  11. Landslides caused by the Klamath Falls, Oregon, earthquakes of September 20, 1993

    USGS Publications Warehouse

    Keefer, D.K.; Schuster, R.L.

    1993-01-01

    In the Klamath Falls area, the most numerous earthquake-induced rock falls were along the east-to southeast-facing flank of a ridge immediately south and west of Howard Bay (locality 1 on the accompanying map), 18 km east-southeast of the epicenter of the magntiude 6.0 shock at 10:45 p.m. This ridge is more than 240 m high and has slopes steeper than 45° in places. The upper part of the ridge is composed of material from basaltic lava flows, an the lower slopes are covered with colluvium and talus deposits containing abundant boulders. 

  12. Coastal uplift and mortality of intertidal organisms caused by the september 1985 Mexico earthquakes.

    PubMed

    Bodin, P; Klinger, T

    1986-09-05

    Coastal uplift associated with the great Mexican earthquake of 19 September 1985 and its principal aftershock produced widespread mortality of intertidal organisms along the coast of the states of Michoacán and Guerrero, Mexico. Measurements of the vertical extent of mortality at ten sites provided estimates of the magnitude of the vertical component of deformation along the coast. Within the affected area, uplift ranged from about 12 centimeters to about 1 meter, and no subsidence was observed. The observations are consistent with models of the tectonic deformation that results from buried slip on a shallow-dipping underthrust fault.

  13. An Examination of Upper Plate Aftershocks of the Tohoku-oki Earthquake: Are They Caused by a Long-term Change in the Dip of the Subducting Plate?

    NASA Astrophysics Data System (ADS)

    Oryan, B.; Buck, W. R.

    2017-12-01

    The Tohoku-oki earthquake was one of the strongest earthquakes ever recorded. 50-80 meters of lateral motion of the sloping seafloor resulted in a tsunami that exceeded predictions and caused one of the costliest natural disasters in history. It was also the first time extensional aftershocks were observed in the upper plate over a region as wide as 250km. Inspired by these findings, researchers found similar upper plate extensional earthquakes after reexamining seismic data from past earthquakes that had also produced large tsunamis. Such extensional aftershocks are difficult to explain in terms of standard subduction models. Most models assume that the dip of the subducting plate remains constant with time. However, geological evidence indicates that the dip angle of the subducting plate changes. We hypothesize that a reduction in the dip angle of the subducting plate can cause upper plate extensional earthquakes. This change in dip angle adds extensional bending stress to the upper plate. During an inter-seismic period, the interface is `locked' causing regional compression that prevents the release of extensional energy. Relief of compressional stresses during a megathrust event can trigger the release of the accumulated extensional energy, explaining why extensional earthquakes were observed after some megathrust events. Numerical models will be used to test our hypothesis. First, we will model long term subduction with a nearly constant dip angle. Then, we will impose a `mantle wind' to reduce the dip angle of the subducting plate. Eventually, we will model a full seismic cycle of the subduction resulting in a megathrust event. The generation of extensional earthquakes in the upper plate of our model following the megathrust event will allow us to determine whether a causal link exists between these earthquakes and a reduction in the dip angle of the subducting plate.

  14. 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.

  15. Hydrologic effects of hypothetical earthquake-caused floods below Jackson Lake, northwestern Wyoming

    USGS Publications Warehouse

    Glass, W.R.; Keefer, T.N.; Rankl, J.G.

    1976-01-01

    Jackson Lake, located in Grand Teton National Park, Wyoming, is in an area of seismic instability. There is a possibility of flooding in the Snake River downstream from Jackson Lake Dam in the event of a severe earthquake. Hypothetical floods were routed 38 miles (61 kilometers) downstream from the dam for three cases: (1) Instantaneous destruction of the dam outlet structure, (2) instantaneous destruction of the entire dam, and (3) for waves overtopping the dam without failure of the dam. In each case, a full reservoir was assumed. Hydrographs for outflow from the reservoir for the two cases of dam failure were developed utilizing an accelerated discharge due to the travel of a negative wave through the reservoir, and Muskingum storage routing. For the case of waves overtopping the dam, a 10-foot (3-meter) wave was assumed to be propagated from the upstream end of the reservori. A multiple-linearization technique was used to route the flow through the reach. The model was calibrated from U.S. Geological Survey streamflow records. Most extensive flooding and largest water velocities would occur if the entire dam were destroyed; floods for the other two cases were smaller. An inundation map was prepared from channel conveyance curves and profiles of the water surface. (Woodard-USGS)

  16. Vegetation recovery patterns assessment at landslides caused by catastrophic earthquake: a case study in central Taiwan.

    PubMed

    Chou, Wen-Chieh; Lin, Wen-Tzu; Lin, Chao-Yuan

    2009-05-01

    The catastrophic earthquake, 7.3 on the Richter scale, occurred on September 21, 1999 in Central Taiwan. Much of standing vegetation on slopes was eliminated and massive, scattered landslides were induced at the Jou-Jou Mountain area of the Wu-Chi basin in Nantou County. We evaluated three methods for assessing landslide hazard and vegetation recovery conditions. (1) Self-organizing map (SOM) neural network coupled with fuzzy technique was used to quickly extract the landslide. (2) The NDVI-based vegetation recovery index derived from multi-temporal SPOT satellite images was used to evaluate vegetation recovery rate in the denudation sites. (3) The spatial distribution index (SDI) based on land-cover topographic location was employed to analyze vegetation recovery patterns, including the invading, surviving and mixed patterns at the Jou-Jou Mountain area. On September 27, 1999, there were 849.20 ha of landslide area extracted using the self-organizing map and fuzzy technique combined model. After six years of natural vegetation succession, the landslide has gradually restored, and vegetation recovery rate reached up to 86%. On-site observation shows that many native pioneer plants have invaded onto the denudation sites even if disturbed by several typhoons. Two native surviving plants, Arundo formosana Hack and Pinus taiwanensis Hayata, play a vital role in natural vegetation succession in this area, especially for the sites on ridgeline and steep slopes.

  17. 47 CFR 51.233 - Significant degradation of services caused by deployment of advanced services.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... deployment of advanced services. 51.233 Section 51.233 Telecommunication FEDERAL COMMUNICATIONS COMMISSION... relevant state commission that a particular technology deployment is causing the significant degradation..., the relevant state commission, must be supported with specific and verifiable information. (d) Where a...

  18. Enchancement of the Ionosphere Alfvén Resonance caused by earthquake: experiment and model

    NASA Astrophysics Data System (ADS)

    Kotsarenko, A.; Grimalsky, V.; Pulinets, S.; Koshevaya, S.; Perez-Enriquez, R.; Cruz Abeyro, J. A. L.

    2009-04-01

    Analysis of geomagnetic and telluric data, measured at the station PRK (Parkfield, ULF flux-gate 3-axial magnetometer) 1 week before (including) the day of major EQ (EarthQuake, Ms=6.0, 28-SEP-2004, 17:15:24) near Parkfield, California, USA, are presented. Spectral analysis reveals enhancement the IAR (Ionosphere Alfvén Resonance) modes, localized in the frequency range 0.25-1 Hz, observed the day before the event, Sep 27, at 15:00-20:00 by UT, and at the day of the EQ, Sep 28, at 11:00-19:00 (9 hours before the event). Estimations of the amplitudes of the signals give following values: up to 20 pT for the magnetic channels and 1.5 mkV/km for the telluric ones. Observed phenomena occurs under quiet geomagnetic conditions (|Dst|< 20 nT). We have calculated the efficiency of the modulation of the Alfvén wave at frequencies f = 0.1 - 10 Hz, which passes from the magnetosphere (z > 600 km) to the ionosphere and the to the Earth's surface and the lithosphere. The set of equations for the both magnetic and electric field components has been solved numerically. It has been obtained that the 20% modulation of the concentration of the ion and electron concentrations (which is also observed experimentally) at the heights z = 200 km can lead to the same (or higher) modulation of the amplitude of the variable magnetic field at the Earth's surface (z = 0) at f = 0.1 - 10 Hz. Moreover, the effect depends weakly on the conductivity of the lithosphere. Therefore, an influence of the coupling mechanisms on the F-layer of the ionosphere could lead to observable effects at the Earth's surface.

  19. Significance of Rib Fractures Potentially Caused by Blunt Impact Non Lethal Weapons

    DTIC Science & Technology

    2017-03-01

    Center Drive Alexandria, Virginia 22311-1882 I N S T I T U T E F O R D E F E N S E A N A L Y S E S Significance of Rib Fractures Potentially...F E N S E A N A L Y S E S IDA Document D-8277 Significance of Rib Fractures Potentially Caused by Blunt-Impact Non-Lethal Weapons Shelley M. Cazares...deterrent by inducing pain or muscle spasm at the site of impact of the affected individual. These weapons may induce rib fractures —the focus of this

  20. Earthquakes at North Atlantic passive margins

    SciTech Connect

    Gregersen, S.; Basham, P.W.

    1989-01-01

    The main focus of this volume is the earthquakes that occur at and near the continental margins on both sides of the North Atlantic. The book, which contains the proceedings of the NATO workshop on Causes and Effects of Earthquakes at Passive Margins and in Areas of Postglacial Rebound on Both Sides of the North Atlantic, draws together the fields of geophysics, geology and geodesy to address the stress and strain in the Earth's crust. The resulting earthquakes produced on ancient geological fault zones and the associated seismic hazards these pose to man are also addressed. Postglacial rebound in Northmore » America and Fennoscandia is a minor source of earthquakes today, during the interglacial period, but evidence is presented to suggest that the ice sheets suppressed earthquake strain while they were in place, and released this strain as a pulse of significant earthquakes after the ice melted about 9000 years ago.« less

  1. Introduced species: A significant component of human-caused global change

    USGS Publications Warehouse

    Vitousek, Peter M.; D'Antonio, Carla M.; Loope, Lloyd L.; Rejmanek, Marcel; Westbrooks, Randy G.

    1997-01-01

    Biological invasions are a widespread and significant component of human-caused global environmental change. The extent of invasions of oceanic islands, and their consequences for native biological diversity, have long been recognized. However, invasions of continental regions also are substantial. For example, more than 2,000 species of alien plants are established in the continental United States. These invasions represent a human-caused breakdown of the regional distinctiveness of Earth's flora and fauna—a substantial global change in and of itself. Moreover, there are well- documented examples of invading species that degrade human health and wealth, alter the structure and functioning of otherwise undisturbed ecosystems, and/or threaten native biological diversity. Invasions also interact synergistically with other components of global change. notably land use change. People and institutions working to understand, prevent, and control invasions are carrying out some of the most important—and potentially most effective—work on global environmental change.

  2. The Loma Prieta earthquake of October 17, 1989 : a brief geologic view of what caused the Loma Prieta earthquake and implications for future California earthquakes: What happened ... what is expected ... what can be done.

    USGS Publications Warehouse

    Ward, Peter L.; Page, Robert A.

    1990-01-01

    The San Andreas fault, in California, is the primary boundary between the North American plate and the Pacific plate. Land west of the fault has been moving northwestward relative to land on the east at an average rate of 2 inches per year for millions of years. This motion is not constant but occurs typically in sudden jumps during large earthquakes. This motion is relentless; therefore earthquakes in California are inevitable.

  3. 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. 

  4. The natural product citral can cause significant damage to the hyphal cell walls of Magnaporthe grisea.

    PubMed

    Li, Rong-Yu; Wu, Xiao-Mao; Yin, Xian-Hui; Liang, Jing-Nan; Li, Ming

    2014-07-15

    In order to find a natural alternative to the synthetic fungicides currently used against the devastating rice blast fungus, Magnaporthe grisea, this study explored the antifungal potential of citral and its mechanism of action. It was found that citral not only inhibited hyphal growth of M. grisea, but also caused a series of marked hyphal morphological and structural alterations. Specifically, citral was tested for antifungal activity against M. grisea in vitro and was found to significantly inhibit colony development and mycelial growth with IC50 and IC90 values of 40.71 and 203.75 μg/mL, respectively. Furthermore, citral reduced spore germination and germ tube length in a concentration-dependent manner. Following exposure to citral, the hyphal cell surface became wrinkled with folds and cell breakage that were observed under scanning electron microscopy (SEM). There was damage to hyphal cell walls and membrane structures, loss of villous-like material outside of the cell wall, thinning of the cell wall, and discontinuities formed in the cell membrane following treatment based on transmission electron microscopy (TEM). This increase in chitinase activity both supports the morphological changes seen in the hyphae, and also suggests a mechanism of action. In conclusion, citral has strong antifungal properties, and treatment with this compound is capable of causing significant damage to the hyphal cell walls of M. grisea.

  5. Landslides caused by the M 7.6 Tecomán, Mexico earthquake of January 21, 2003

    USGS Publications Warehouse

    Keefer, David K.; Wartman, Joseph; Navarro, Ochoa C.; Rodriguez-Marek, Adrian; Wieczorek, Gerald F.

    2006-01-01

    In contrast to the coastal cordilleras, the volcanic rocks to the north were more susceptible to the occurrence of seismically triggered landslides. The greatest number and concentrations of landslides occurred there, and the landslides were larger than those in the coastal cordilleras, even though this volcanic terrain was farther from the earthquake source. Here, stretches of river bluffs several hundred meters long had been stripped of vegetation and surficial material by coalescing landslides, and several days after the main shock, thousands of small rock falls were still occurring each day, indicating an ongoing hazard. The high susceptibility of volcanic materials to earthquake-generated landslides conforms to findings in other recent earthquakes.

  6. Scapulothoracic bursitis as a significant cause of breast and chest wall pain: underrecognized and undertreated.

    PubMed

    Boneti, Cristiano; Arentz, Candy; Klimberg, V Suzanne

    2010-10-01

    Pain is one of the most commonly reported breast complaints. Referred pain from inflammation of the shoulder bursa is often overlooked as a cause of breast pain. The objective of this study is to evaluate the role of shoulder bursitis as a cause of breast/chest pain. An IRB-approved retrospective review from July 2005 to September 2009 identified 461 patients presenting with breast/chest pain. Cases identified with a trigger point in the medial aspect of the ipsilateral scapula were treated with a bursitis injection at the point of maximum tenderness. The bursitis injection contains a mixture of local anesthetic and corticosteroid. Presenting complaint, clinical response and associated factors were recorded and treated with descriptive statistics. Average age of the study group was 53.4 ± 12.7 years, and average BMI was 30.4 ± 7.4. One hundred and three patients were diagnosed with shoulder bursitis as the cause of breast pain and received the bursitis injection. Most cases (81/103 or 78.6%) presented with the breast/chest as the site of most significant discomfort, where 8.7% (9/103) had the most severe pain at the shoulder, 3.9% (4/103) at the axilla and 3.9% (4/103) at the medial scapular border. Of the treated patients, 83.5% (86/103) had complete relief of the pain, 12.6% (13/103) had improvement of symptoms with some degree of residual pain, and only 3.9%(4/103) did not respond at all to the treatment. The most commonly associated factor to the diagnosis of bursitis was the history of a previous mastectomy, present in 27.2% (28/103) of the cases. Shoulder bursitis represents a significant cause of breast/chest pain (22.3% or 103/461) and can be successfully treated with a local injection at site of maximum tenderness in the medial scapular border.

  7. [Comparative analysis of the clinical characteristics of orthopedic inpatients in Lushan and Wenchuan earthquakes].

    PubMed

    Shi, Xiao-Jun; Wang, Guang-Lin; Pei, Fu-Xing; Song, Yue-Ming; Yang, Tian-Fu; Tu, Chong-Qi; Huang, Fu-Guo; Liu, Hao; Lin, Wei

    2013-10-18

    To systematically analyze and compare the clinical characteristics of orthopedic inpatients in Lushan and Wenchuan earthquake, so as to provide useful references for future earthquakes injury rescue. Based on the orthopedic inpatients in Lushan and Wenchuan earthquakes, the data of the age, gender, injury causes, body injured parts and speed of transport were classified and compared. The duration of patients admitted to hospital lasted long and the peak appeared late in Wenchuan earthquake, which is totally opposed to Lushan earthquake. There was no significant difference in the patient's age and gender between the two earthquakes. However, the occurrence rate of crush syndrome, amputation, gas gangrene, vascular injury and multiple organ dysfunction syndrome (MODS) in Wenchuan earthquake was much higher than that in Lushan earthquake. Blunt traumas or crush-related injuries (79.6%) are the major injury cause in Wenchuan earthquake, however, high falling injuries and falls (56.8%) are much higher than blunt trauma or crush-related injuries (39.2%) in Lushan earthquake. The incidence rate of foot fractures, spine fractures and multiple fractures in Lushan earthquake was higher than that in Wenchuan earthquake, but that of open fractures and lower limb fractures was lower than that in Wenchuan earthquake. The rapid rescue scene is the cornerstone of successful treatment, early rescue and transport obviously reduce the incidence of the wound infection, crush syndrome, MODS and amputation. Popularization of correct knowledge of emergency shelters will help to reduce the damage caused by blindly jumping or escaping while earthquake happens.

  8. 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

    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.

  9. Graphene oxide significantly inhibits cell growth at sublethal concentrations by causing extracellular iron deficiency.

    PubMed

    Yu, Qilin; Zhang, Bing; Li, Jianrong; Du, Tingting; Yi, Xiao; Li, Mingchun; Chen, Wei; Alvarez, Pedro J J

    Graphene oxide (GO)-based materials are increasingly being used in medical materials and consumer products. However, their sublethal effects on biological systems are poorly understood. Here, we report that GO (at 10 to 160 mg/L) induced significant inhibitory effects on the growth of different unicellular organisms, including eukaryotes (i.e. Saccharomyces cerevisiae, Candida albicans, and Komagataella pastoris) and prokaryotes (Pseudomonas fluorescens). Growth inhibition could not be explained by commonly reported cytotoxicity mechanisms such as plasma membrane damage or oxidative stress. Based on transcriptomic analysis and measurement of extra- and intracellular iron concentrations, we show that the inhibitory effect of GO was mainly attributable to iron deficiency caused by binding to the O-functional groups of GO, which sequestered iron and disrupted iron-related physiological and metabolic processes. This inhibitory mechanism was corroborated with supplementary experiments, where adding bathophenanthroline disulfonate-an iron chelating agent-to the culture medium exerted similar inhibition, whereas removing surface O-functional groups of GO decreased iron sequestration and significantly alleviated the inhibitory effect. These findings highlight a potential indirect detrimental effect of nanomaterials (i.e. scavenging of critical nutrients), and encourage research on potential biomedical applications of GO-based materials to sequester iron and enhance treatment of iron-dependent diseases such as cancer and some pathogenic infections.

  10. 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. 

  11. Earthquakes: Predicting the unpredictable?

    USGS Publications Warehouse

    Hough, Susan E.

    2005-01-01

    The earthquake prediction pendulum has swung from optimism in the 1970s to rather extreme pessimism in the 1990s. Earlier work revealed evidence of possible earthquake precursors: physical changes in the planet that signal that a large earthquake is on the way. Some respected earthquake scientists argued that earthquakes are likewise fundamentally unpredictable. The fate of the Parkfield prediction experiment appeared to support their arguments: A moderate earthquake had been predicted along a specified segment of the central San Andreas fault within five years of 1988, but had failed to materialize on schedule. At some point, however, the pendulum began to swing back. Reputable scientists began using the "P-word" in not only polite company, but also at meetings and even in print. If the optimism regarding earthquake prediction can be attributed to any single cause, it might be scientists' burgeoning understanding of the earthquake cycle.

  12. Nanoseismicity and picoseismicity rate changes from static stress triggering caused by a Mw 2.2 earthquake in Mponeng gold mine, South Africa

    NASA Astrophysics Data System (ADS)

    Kozłowska, Maria; Orlecka-Sikora, Beata; Kwiatek, Grzegorz; Boettcher, Margaret S.; Dresen, Georg

    2015-01-01

    Static stress changes following large earthquakes are known to affect the rate and distribution of aftershocks, yet this process has not been thoroughly investigated for nanoseismicity and picoseismicity at centimeter length scales. Here we utilize a unique data set of M ≥ -3.4 earthquakes following a Mw 2.2 earthquake in Mponeng gold mine, South Africa, that was recorded during a quiet interval in the mine to investigate if rate- and state-based modeling is valid for shallow, mining-induced seismicity. We use Dieterich's (1994) rate- and state-dependent formulation for earthquake productivity, which requires estimation of four parameters: (1) Coulomb stress changes due to the main shock, (2) the reference seismicity rate, (3) frictional resistance parameter, and (4) the duration of aftershock relaxation time. Comparisons of the modeled spatiotemporal patterns of seismicity based on two different source models with the observed distribution show that while the spatial patterns match well, the rate of modeled aftershocks is lower than the observed rate. To test our model, we used three metrics of the goodness-of-fit evaluation. The null hypothesis, of no significant difference between modeled and observed seismicity rates, was only rejected in the depth interval containing the main shock. Results show that mining-induced earthquakes may be followed by a stress relaxation expressed through aftershocks located on the rupture plane and in regions of positive Coulomb stress change. Furthermore, we demonstrate that the main features of the temporal and spatial distributions of very small, mining-induced earthquakes can be successfully determined using rate- and state-based stress modeling.

  13. Significant Climate Changes Caused by Soot Emitted From Rockets in the Stratosphere

    NASA Astrophysics Data System (ADS)

    Mills, M. J.; Ross, M.; Toohey, D. W.

    2010-12-01

    A new type of hydrocarbon rocket engine with a larger soot emission index than current kerosene rockets is expected to power a fleet of suborbital rockets for commercial and scientific purposes in coming decades. At projected launch rates, emissions from these rockets will create a persistent soot layer in the northern middle stratosphere that would disproportionally affect the Earth’s atmosphere and cryosphere. A global climate model predicts that thermal forcing in the rocket soot layer will cause significant changes in the global atmospheric circulation and distributions of ozone and temperature. Tropical ozone columns decline as much as 1%, while polar ozone columns increase by up to 6%. Polar surface temperatures rise one Kelvin regionally and polar summer sea ice fractions shrink between 5 - 15%. After 20 years of suborbital rocket fleet operation, globally averaged radiative forcing (RF) from rocket soot exceeds the RF from rocket CO_{2} by six orders of magnitude, but remains small, comparable to the global RF from aviation. The response of the climate system is surprising given the small forcing, and should be investigated further with different climate models.

  14. Significant role of serum CRP in differentiating inflammatory from non-inflammatory causes of thyrotoxicosis

    PubMed Central

    Baruah, Manash P.; Bhattacharya, Bhaskar

    2012-01-01

    Background: C-reactive protein (CRP), which is a marker of inflammation, has not been widely studied in inflammatory thyroid disorders particularly in sub-acute thyroiditis (SAT). Aim: This study was aimed to find the significance of CRP level rise in patients with SAT and compare that to the rise in erythrocyte sedimentation rate (ESR), a gold standard laboratory parameter in establishing the diagnosis of SAT. Materials and Methods: Serum CRP levels were measured at initial presentation in 28 subjects with SAT(12 male, 16 female, age (Mean +SD) 37.96 ±8.5 years),and 19 patients with Graves’ disease (2 male, 17 female, age [Mean +SD] 36.8 ±16.5 years) as controls. Erythrocyte sedimentation rate (ESR) was measured in all 28 patients with SAT by Westergrens’ method. Either Tc99 nucleotide thyroid scan or high resolution ultrasonography (HR-USG) was performed to differentiate SAT from Graves’ disease.Fine needle aspiration cytology (FNAC) of thyroid was performed selected patients. Results: Serum CRP level was high in 61% of SAT patients but in none of the Graves′patients. Mean (SEM) (90%CI) serum CRP level (mg/L) was also significantly higher (P <0.0004) in the SAT group [27.55 (5.76) (15.72-39.38)], than in the Graves’ group [4.09 (0.12) (3.81-4.36)]. The sensitivity of serum CRP was 73.33%, specificity 53.85%, positive predictive value (PPV) 64.71%, and negative predictive value (NPV) 63.64% as compared to the sensitivity (53.57%), specificity (15.38%), PPV (57.69 %), and NPV (13.33%) of ESR. Conclusion: There is significantly higher rise in serum CRP level in patients with SAT is compared to patients with Graves’ disease. It correlates well with the rise in ESR. Such findings of this pilot study highlight the scope of using serum CRP as a diagnostic marker of SAT specially in situations when it may be confused with Graves’ disease, another common cause of thyrotoxicosis. It is logical to carry out studies to find a particular cut-off for serum CRP

  15. Significant role of serum CRP in differentiating inflammatory from non-inflammatory causes of thyrotoxicosis.

    PubMed

    Baruah, Manash P; Bhattacharya, Bhaskar

    2012-11-01

    C-reactive protein (CRP), which is a marker of inflammation, has not been widely studied in inflammatory thyroid disorders particularly in sub-acute thyroiditis (SAT). This study was aimed to find the significance of CRP level rise in patients with SAT and compare that to the rise in erythrocyte sedimentation rate (ESR), a gold standard laboratory parameter in establishing the diagnosis of SAT. Serum CRP levels were measured at initial presentation in 28 subjects with SAT(12 male, 16 female, age (Mean +SD) 37.96 ±8.5 years),and 19 patients with Graves' disease (2 male, 17 female, age [Mean +SD] 36.8 ±16.5 years) as controls. Erythrocyte sedimentation rate (ESR) was measured in all 28 patients with SAT by Westergrens' method. Either Tc(99) nucleotide thyroid scan or high resolution ultrasonography (HR-USG) was performed to differentiate SAT from Graves' disease.Fine needle aspiration cytology (FNAC) of thyroid was performed selected patients. Serum CRP level was high in 61% of SAT patients but in none of the Graves'patients. Mean (SEM) (90%CI) serum CRP level (mg/L) was also significantly higher (P <0.0004) in the SAT group [27.55 (5.76) (15.72-39.38)], than in the Graves' group [4.09 (0.12) (3.81-4.36)]. The sensitivity of serum CRP was 73.33%, specificity 53.85%, positive predictive value (PPV) 64.71%, and negative predictive value (NPV) 63.64% as compared to the sensitivity (53.57%), specificity (15.38%), PPV (57.69 %), and NPV (13.33%) of ESR. There is significantly higher rise in serum CRP level in patients with SAT is compared to patients with Graves' disease. It correlates well with the rise in ESR. Such findings of this pilot study highlight the scope of using serum CRP as a diagnostic marker of SAT specially in situations when it may be confused with Graves' disease, another common cause of thyrotoxicosis. It is logical to carry out studies to find a particular cut-off for serum CRP which can serve as an objective parameter for grading the inflammation in

  16. 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.

  17. Constrained parameterisation of photosynthetic capacity causes significant increase of modelled tropical vegetation surface temperature

    NASA Astrophysics Data System (ADS)

    Kattge, J.; Knorr, W.; Raddatz, T.; Wirth, C.

    2009-04-01

    Photosynthetic capacity is one of the most sensitive parameters of terrestrial biosphere models whose representation in global scale simulations has been severely hampered by a lack of systematic analyses using a sufficiently broad database. Due to its coupling to stomatal conductance changes in the parameterisation of photosynthetic capacity may potentially influence transpiration rates and vegetation surface temperature. Here, we provide a constrained parameterisation of photosynthetic capacity for different plant functional types in the context of the photosynthesis model proposed by Farquhar et al. (1980), based on a comprehensive compilation of leaf photosynthesis rates and leaf nitrogen content. Mean values of photosynthetic capacity were implemented into the coupled climate-vegetation model ECHAM5/JSBACH and modelled gross primary production (GPP) is compared to a compilation of independent observations on stand scale. Compared to the current standard parameterisation the root-mean-squared difference between modelled and observed GPP is substantially reduced for almost all PFTs by the new parameterisation of photosynthetic capacity. We find a systematic depression of NUE (photosynthetic capacity divided by leaf nitrogen content) on certain tropical soils that are known to be deficient in phosphorus. Photosynthetic capacity of tropical trees derived by this study is substantially lower than standard estimates currently used in terrestrial biosphere models. This causes a decrease of modelled GPP while it significantly increases modelled tropical vegetation surface temperatures, up to 0.8°C. These results emphasise the importance of a constrained parameterisation of photosynthetic capacity not only for the carbon cycle, but also for the climate system.

  18. Impact of earthquakes on sex ratio at birth: Eastern Marmara earthquakes

    PubMed Central

    Doğer, Emek; Çakıroğlu, Yiğit; Köpük, Şule Yıldırım; Ceylan, Yasin; Şimşek, Hayal Uzelli; Çalışkan, Eray

    2013-01-01

    Objective: Previous reports suggest that maternal exposure to acute stress related to earthquakes affects the sex ratio at birth. Our aim was to examine the change in sex ratio at birth after Eastern Marmara earthquake disasters. Material and Methods: This study was performed using the official birth statistics from January 1997 to December 2002 – before and after 17 August 1999, the date of the Golcuk Earthquake – supplied from the Turkey Statistics Institute. The secondary sex ratio was expressed as the male proportion at birth, and the ratio of both affected and unaffected areas were calculated and compared on a monthly basis using data from gender with using the Chi-square test. Results: We observed significant decreases in the secondary sex ratio in the 4th and 8th months following an earthquake in the affected region compared to the unaffected region (p= 0.001 and p= 0.024). In the earthquake region, the decrease observed in the secondary sex ratio during the 8th month after an earthquake was specific to the period after the earthquake. Conclusion: Our study indicated a significant reduction in the secondary sex ratio after an earthquake. With these findings, events that cause sudden intense stress such as earthquakes can have an effect on the sex ratio at birth. PMID:24592082

  19. Theoretical computation of internal co- and post-seismic deformation fields caused by great earthquakes in a spherically stratified viscoelastic earth

    NASA Astrophysics Data System (ADS)

    Takagi, Y.; Okubo, S.

    2016-12-01

    Internal co- and post-seismic deformation fields such as strain and stress changes have been modelled in order to study their effects on the subsequent earthquake and/or volcanic activity around the epicentre. When modelling strain or stress changes caused by great earthquakes (M>9.0), we should use a realistic earth model including earth's curvature and stratification; according to Toda et al.'s (2011) result, the stress changes caused by the 2011 Tohoku-oki earthquake (Mw=9.0) exceed 0.1 bar (0.01 MPa) even at the epicentral distance over 400 km. Although many works have been carried out to compute co- and post-seismic surface deformation fields using a spherically stratified viscoelastic earth (e.g. Piersanti et al. 1995; Pollitz 1996, 1997; Tanaka et al. 2006), less attention has been paid to `internal' deformation fields. Tanaka et al. (2006) succeeded in computing post-seismic surface displacements in a continuously stratified compressible viscoelastic earth by evaluating the inverse Laplace integration numerically. To our regret, however, their method cannot calculate internal deformation because they use Okubo's (1993) reciprocity theorem. We found that Okubo's (1993) reciprocity theorem can be extended to computation of internal deformation fields. In this presentation, we show a method of computing internal co- and post-seismic deformation fields and discuss the effects of earth's curvature and stratification on them.

  20. Using SSTAs (Significant Sequences of TIR Anomalies) to trigger Natural Time Analysis: a Long Term Study on Earthquakes (M>4) occurred over Greece in 2004-2013

    NASA Astrophysics Data System (ADS)

    Tramutoli, V.; Eleftheriou, A.; Filizzola, C.; Genzano, N.; Lacava, T.; Lisi, M.; Paciello, R.; Pergola, N.; Vallianatos, F.

    2016-12-01

    From an appropriate identification and real-time integration of independent observations we expect to significantly improve our present capability of dynamically assess Seismic Hazard. Sometime one specific observation (e.g. anomaly in one parameter) can be used as a trigger or as a reference point (in the space and/or time domain) for activating/improving analysis on other independent parameters (e.g. b-value computation and/or Natural Time Analysis on seismic data) whose systematic computation could result otherwise very computationally expensive or impossible. In this paper one of these parameter (the Earth's emitted radiation in the Thermal Infra-Red spectral region) will be used to drive the application of Natural Time Analysis of seismic data in order to verify possible improvements in the forecast of earthquakes (with M≥4) occurred in Greece in the 10 years period 2004-2013. The RST (Robust Satellite Technique) data analysis approach and RETIRA (Robust Estimator of TIR Anomalies) index were used to preliminarily define, and then to identify, Significant Sequences of TIR Anomalies (SSTAs) in 10 years (2004-2013) of daily TIR images acquired by the Spinning Enhanced Visible and Infrared Imager (SEVIRI) on board the Meteosat Second Generation (MSG) satellite. A previous paper already demonstrated that more than 93% of all identified SSTAs occurred in a pre-fixed space-time window around earthquakes time (30 days before up to 15 after) and location (within 150 km or Dorbrovolsky distance) with a false positive rate smaller than 7%. In this paper just the barycenter of (and not all the alerted area) SSTAs is used to define the center of the circular area from which collect seismic data required for NTA analysis. Changes in the quality of earthquake forecast achieved by using each individual parameter in different configurations as well as the improvement rising by their joint use will be presented with reference to the 10 years considered period and to several

  1. Congenital Cytomegalovirus Infection: A Significant Cause of Deafness and Mental Deficiency.

    ERIC Educational Resources Information Center

    Eichhorn, Sarah K.

    1982-01-01

    Research on cytomegalovirus (CMV), a herpes virus causing neurological damage (hearing problems and/or mental retardation) in 10 percent of infants born with the condition, is reviewed. Incidence of hearing and retardation in CMV cases is reported and current treatment described. (CL)

  2. Earthquakes; July-August, 1978

    USGS Publications Warehouse

    Person, W.J.

    1979-01-01

    Earthquake activity during this period was about normal. Deaths from earthquakes were reported from Greece and Guatemala. Three major earthquakes (magnitude 7.0-7.9) occurred in Taiwan, Chile, and Costa Rica. In the United States, the most significant earthquake was a magnitude 5.6 on August 13 in southern California. 

  3. 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. 

  4. Remotely triggered earthquakes following moderate main shocks

    USGS Publications Warehouse

    Hough, S.E.

    2007-01-01

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

  5. Causes of unusual distribution of coseismic landslides triggered by the Mw 6.1 2014 Ludian, Yunnan, China earthquake

    NASA Astrophysics Data System (ADS)

    Chen, Xiao-li; Liu, Chun-guo; Wang, Ming-ming; Zhou, Qing

    2018-06-01

    The Mw 6.1 2014 Ludian, Yunnan, China earthquake triggered numerous coseismic landslides that do not appear to be associated with any previously known seismogenic fault. Traditional models of triggering for seismically generated landslides do not provide a reasonable explanation for the landslide pattern observed here. Here the Newmark method is applied to a grid to calculate the minimum accelerations required for slope failures throughout the affected region. The results demonstrate that for much of the study area, the distribution of failure prone slopes is similar to the actual pattern of coseismic landslides, however there are some areas where the model predicts considerably fewer failures than occurred. We suggest that this is a result of the complex source faults that generated the Ludian earthquake, which produced a half-conjugate rupture on nearly EW- and NNW trending faults at depth. The rupture directed much of its seismic moment southeast of the epicenter, increasing ground shaking and the number of resulting landslides.

  6. Stress transfer among en echelon and opposing thrusts and tear faults: Triggering caused by the 2003 Mw = 6.9 Zemmouri, Algeria, earthquake

    USGS Publications Warehouse

    Lin, J.; Stein, R.S.; Meghraoui, M.; Toda, S.; Ayadi, A.; Dorbath, C.; Belabbes, S.

    2011-01-01

    The essential features of stress interaction among earthquakes on en echelon thrusts and tear faults were investigated, first through idealized examples and then by study of thrust faulting in Algeria. We calculated coseismic stress changes caused by the 2003 Mw = 6.9 Zemmouri earthquake, finding that a large majority of the Zemmouri afterslip sites were brought several bars closer to Coulomb failure by the coseismic stresses, while the majority of aftershock nodal planes were brought closer to failure by an average of ~2 bars. Further, we calculated that the shallow portions of the adjacent Thenia tear fault, which sustained ~0.25 m slip, were brought >2 bars closer to failure. We calculated that the Coulomb stress increased by 1.5 bars on the deeper portions of the adjacent Boumerdes thrust, which lies just 10–20 km from the city of Algiers; both the Boumerdes and Thenia faults were illuminated by aftershocks. Over the next 6 years, the entire south dipping thrust system extending 80 km to the southwest experienced an increased rate of seismicity. The stress also increased by 0.4 bar on the east Sahel thrust fault west of the Zemmouri rupture. Algiers suffered large damaging earthquakes in A.D. 1365 and 1716 and is today home to 3 million people. If these shocks occurred on the east Sahel fault and if it has a ~2 mm/yr tectonic loading rate, then enough loading has accumulated to produce a Mw = 6.6–6.9 shock today. Thus, these potentially lethal faults need better understanding of their slip rate and earthquake history.

  7. Three-dimensional deformation caused by the Bam, Iran, earthquake and the origin of shallow slip deficit.

    PubMed

    Fialko, Yuri; Sandwell, David; Simons, Mark; Rosen, Paul

    2005-05-19

    Our understanding of the earthquake process requires detailed insights into how the tectonic stresses are accumulated and released on seismogenic faults. We derive the full vector displacement field due to the Bam, Iran, earthquake of moment magnitude 6.5 using radar data from the Envisat satellite of the European Space Agency. Analysis of surface deformation indicates that most of the seismic moment release along the 20-km-long strike-slip rupture occurred at a shallow depth of 4-5 km, yet the rupture did not break the surface. The Bam event may therefore represent an end-member case of the 'shallow slip deficit' model, which postulates that coseismic slip in the uppermost crust is systematically less than that at seismogenic depths (4-10 km). The InSAR-derived surface displacement data from the Bam and other large shallow earthquakes suggest that the uppermost section of the seismogenic crust around young and developing faults may undergo a distributed failure in the interseismic period, thereby accumulating little elastic strain.

  8. [Significance of Hypoxia-related microRNA for Estimating the Cause of Mechanical Asphyxia Death].

    PubMed

    Zeng, Y; Ma, J L; Chen, L

    2017-02-01

    Under hypoxia condition, microRNA (miRNA) can interact with transcription factors for regulating the cell metabolism, angiogenesis, erythropoiesis, cellular proliferation, differentiation and apoptosis. The biological processes above may play an important role in mechanical asphyxia death. This article reviews the regulating function of miRNA under hypoxia condition and the influence of hypoxia to biosynthesis of miRNA, which may provide some new ideas to the research of miRNA on determining the cause of mechanical asphyxia death in the field of forensic medicine. Copyright© by the Editorial Department of Journal of Forensic Medicine.

  9. [Mechanism Causing Abnormal Laboratory Data--Significance of Electrophoresis and Information Transmission--Chairmen's Introductory Remarks].

    PubMed

    Maekawa, Masato; Fujita, Kiyotaka

    2014-11-01

    Abnormal laboratory data are observed due to some kinds of modification as well as pathological conditions of patients. Elucidation of the causal mechanism is very important for clinical laboratories. This symposium was planned to highlight the significance of electrophoresis. Electrophoresis is one of the most important tools to provide clinicians with information for medical diagnosis and care.

  10. Two Cases of Tsunami Dust Pneumonia: Organizing Pneumonia Caused by the Inhalation of Dried Tsunami Sludge after the 2011 Great East Japan Earthquake.

    PubMed

    Yamanda, Shinsuke; Kobayashi, Seiichi; Hanagama, Masakazu; Sato, Hikari; Suzuki, Satoshi; Ueda, Shinsaku; Takahashi, Toru; Yanai, Masaru

    We report two cases of organizing pneumonia (OP) secondary to the inhalation of the dried tsunami sludge which formed during the 2011 Great East Japan Earthquake and the consequent tsunami. After the disaster, both of these patients had been engaged in the restoration work. About half a month later, they developed shortness of breath and pulmonary infiltrates. These patients were diagnosed with interstitial pneumonia. Their biopsy specimens revealed multifocal peribronchiolitis and OP. An electron probe microanalysis of these specimens demonstrated the presence of elements from the earth's crust in the inflammatory lesions. These two cases indicate that exposure to dried tsunami sludge can cause OP.

  11. Observation and prediction of dynamic ground strains, tilts, and torsions caused by the Mw 6.0 2004 Parkfield, California, earthquake and aftershocks, derived from UPSAR array observations

    USGS Publications Warehouse

    Spudich, P.; Fletcher, Joe B.

    2008-01-01

    The 28 September 2004 Parkfield, California, earthquake (Mw 6.0) and four aftershocks (Mw 4.7-5.1) were recorded on 12 accelerograph stations of the U.S. Geological Survey Parkfield seismic array (UPSAR), an array of three-component accelerographs occupying an area of about 1 km2 located 8.8 km from the San Andreas fault. Peak horizontal acceleration and velocity at UPSAR during the mainshock were 0.45g and 27 cm/sec, respectively. We determined both time-varying and peak values of ground dilatations, shear strains, torsions, tilts, torsion rates, and tilt rates by applying a time-dependent geodetic analysis to the observed array displacement time series. Array-derived dilatations agree fairly well with point measurements made on high sample rate recordings of the Parkfield-area dilatometers (Johnston et al., 2006). Torsion Fourier amplitude spectra agree well with ground velocity spectra, as expected for propagating plane waves. A simple predictive relation, using the predicted peak velocity from the Boore-Atkinson ground-motion prediction relation (Boore and Atkinson, 2007) scaled by a phase velocity of 1 km/sec, predicts observed peak Parkfield and Chi-Chi rotations (Huang, 2003) well. However, rotation rates measured during Mw 5 Ito, Japan, events observed on a gyro sensor (Takeo, 1998) are factors of 5-60 greater than those predicted by our predictive relation. This discrepancy might be caused by a scale dependence in rotation, with rotations measured over a short baseline exceeding those measured over long baselines. An alternative hypothesis is that events having significant non-double-couple mechanisms, like the Ito events, radiate much stronger rotations than double-couple events. If this is true, then rotational observations might provide an important source of new information for monitoring seismicity in volcanic areas.

  12. A media player causes clinically significant telemetry interference with implantable loop recorders.

    PubMed

    Thaker, Jay P; Patel, Mehul B; Shah, Ashok J; Liepa, Valdis V; Jongnarangsin, Krit; Thakur, Ranjan K

    2009-03-01

    The implantable loop recorder is a useful diagnostic tool for intermittent cardiovascular symptoms because it can automatically record arrhythmias as well as a patient-triggered ECG. Media players have been shown to cause telemetry interference with pacemakers. Telemetry interference may be important in patients with implantable loop recorders because capturing a patient-triggered ECG requires a telemetry link between a hand-held activator and the implanted device. The purpose of this study was to determine if a media player causes interference with implantable loop recorders. Fourteen patients with implantable loop recorders underwent evaluation for interference with a 15 GB third generation iPod (Apple, Inc.) media player. All patients had the Reveal Plus (Medtronic, Inc.) implantable loop recorder. We tested for telemetry interference on the programmer by first establishing a telemetry link with the loop recorder and then, the media player was placed next to it, first turned off and then, on. We evaluated for telemetry interference between the activator and the implanted device by placing the activator over the device (normal use) and the media player next to it, first turned off and then, on. We made 5 attempts to capture a patient-triggered ECG by depressing the activator switch 5 times while the media player was off or on. Telemetry interference on the programmer screen, consisting of either high frequency spikes or blanking of the ECG channel was seen in all patients. Telemetry interference with the activator resulted in failure to capture an event in 7 patients. In one of these patients, a green indicator light on the activator suggested that a patient-triggered event was captured, but loop recorder interrogation did not show a captured event. In the remaining 7 patients, an event was captured and appropriately recognized by the device at least 1 out of 5 times. A media player playing in close proximity to an implanted loop recorder may interfere with

  13. Leptin receptors are expressed in coronary arteries, and hyperleptinemia causes significant coronary endothelial dysfunction.

    PubMed

    Knudson, Jarrod D; Dincer, U Deniz; Zhang, Cuihua; Swafford, Albert N; Koshida, Ryoji; Picchi, Andrea; Focardi, Marta; Dick, Gregory M; Tune, Johnathan D

    2005-07-01

    Obesity is associated with marked increases in plasma leptin concentration, and hyperleptinemia is an independent risk factor for coronary artery disease. As a result, the purpose of this investigation was to test the following hypotheses: 1) leptin receptors are expressed in coronary endothelial cells; and 2) hyperleptinemia induces coronary endothelial dysfunction. RT-PCR analysis revealed that the leptin receptor gene is expressed in canine coronary arteries and human coronary endothelium. Furthermore, immunocytochemistry demonstrated that the long-form leptin receptor protein (ObRb) is present in human coronary endothelium. The functional effects of leptin were determined using pressurized coronary arterioles (<130 microm) isolated from Wistar rats, Zucker rats, and mongrel dogs. Leptin induced pharmacological vasodilation that was abolished by denudation and the nitric oxide synthase inhibitor N(omega)-nitro-l-arginine methyl ester and was absent in obese Zucker rats. Intracoronary leptin dose-response experiments were conducted in anesthetized dogs. Normal and obese concentrations of leptin (0.1-3.0 microg/min ic) did not significantly change coronary blood flow or myocardial oxygen consumption; however, obese concentrations of leptin significantly attenuated the dilation to graded intracoronary doses of acetylcholine (0.3-30.0 microg/min). Additional experiments were performed in canine coronary rings, and relaxation to acetylcholine (6.25 nmol/l-6.25 micromol/l) was significantly attenuated by obese concentrations of leptin (625 pmol/l) but not by physiological concentrations of leptin (250 pmol/l). The major findings of this investigation were as follows: 1) the ObRb is present in coronary arteries and coupled to pharmacological, nitric oxide-dependent vasodilation; and 2) hyperleptinemia produces significant coronary endothelial dysfunction.

  14. Significance of heme-based respiration in meat spoilage caused by Leuconostoc gasicomitatum.

    PubMed

    Jääskeläinen, Elina; Johansson, Per; Kostiainen, Olli; Nieminen, Timo; Schmidt, Georg; Somervuo, Panu; Mohsina, Marzia; Vanninen, Paula; Auvinen, Petri; Björkroth, Johanna

    2013-02-01

    Leuconostoc gasicomitatum is a psychrotrophic lactic acid bacterium (LAB) which causes spoilage in cold-stored modified-atmosphere-packaged (MAP) meat products. In addition to the fermentative metabolism, L. gasicomitatum is able to respire when exogenous heme and oxygen are available. In this study, we investigated the respiration effects on growth rate, biomass, gene expression, and volatile organic compound (VOC) production in laboratory media and pork loin. The meat samples were evaluated by a sensory panel every second or third day for 29 days. We observed that functional respiration increased the growth (rate and yield) of L. gasicomitatum in laboratory media with added heme and in situ meat with endogenous heme. Respiration increased enormously (up to 2,600-fold) the accumulation of acetoin and diacetyl, which are buttery off-odor compounds in meat. Our transcriptome analyses showed that the gene expression patterns were quite similar, irrespective of whether respiration was turned off by excluding heme from the medium or mutating the cydB gene, which is essential in the respiratory chain. The respiration-based growth of L. gasicomitatum in meat was obtained in terms of population development and subsequent development of sensory characteristics. Respiration is thus a key factor explaining why L. gasicomitatum is so well adapted in high-oxygen packed meat.

  15. Detection of Subtle Hydromechanical Medium Changes Caused By a Small-Magnitude Earthquake Swarm in NE Brazil

    NASA Astrophysics Data System (ADS)

    D'Hour, V.; Schimmel, M.; Do Nascimento, A. F.; Ferreira, J. M.; Lima Neto, H. C.

    2016-04-01

    Ambient noise correlation analyses are largely used in seismology to map heterogeneities and to monitor the temporal evolution of seismic velocity changes associated mostly with stress field variations and/or fluid movements. Here we analyse a small earthquake swarm related to a main mR 3.7 intraplate earthquake in North-East of Brazil to study the corresponding post-seismic effects on the medium. So far, post-seismic effects have been observed mainly for large magnitude events. In our study, we show that we were able to detect localized structural changes even for a small earthquake swarm in an intraplate setting. Different correlation strategies are presented and their performances are also shown. We compare the classical auto-correlation with and without pre-processing, including 1-bit normalization and spectral whitening, and the phase auto-correlation. The worst results were obtained for the pre-processed data due to the loss of waveform details. The best results were achieved with the phase cross-correlation which is amplitude unbiased and sensitive to small amplitude changes as long as there exist waveform coherence superior to other unrelated signals and noise. The analysis of 6 months of data using phase auto-correlation and cross-correlation resulted in the observation of a progressive medium change after the major recorded event. The progressive medium change is likely related to the swarm activity through opening new path ways for pore fluid diffusion. We further observed for the auto-correlations a lag time frequency-dependent change which likely indicates that the medium change is localized in depth. As expected, the main change is observed along the fault.

  16. Use of high resolution satellite images for tracking of changes in the lineament structure, caused by earthquakes, situated nearly the Pacific coast of the North and South America.

    NASA Astrophysics Data System (ADS)

    Arellano-Baeza, A. A.; Garcia, R. V.; Trejo-Soto, M.

    The Pacific coast of the North and South America is one of the most seismically and volcanically active regions in the world forming part of the so-called Ring of Fire More than 10 earthquakes with the Richter scale magnitude 4 5 were analyzed They were located in the regions with small seasonal variations and limited vegetation to facilitate the tracking of features associated with the seismic activity only High resolution Aster satellite images were used to extract the principal lineaments using The Lineament Extraction and Stripes Statistic Analysis LESSA software package It was found that the number and orientation of lineaments changed significantly about one month before an earthquake approximately and a few months later the system returns to its initial state This effect increases with the earthquake magnitude and it is much more easily detectable in case of convergent plate boundaries for example Nasca and South American plates The results obtained open the possibility to develop a methodology able to evaluate the seismic risk in the regions with similar geological conditions

  17. Earthquake Hazard in the Heart of the Homeland

    USGS Publications Warehouse

    Gomberg, Joan; Schweig, Eugene

    2007-01-01

    Evidence that earthquakes threaten the Mississippi, Ohio, and Wabash River valleys of the Central United States abounds. In fact, several of the largest historical earthquakes to strike the continental United States occurred in the winter of 1811-1812 along the New Madrid seismic zone, which stretches from just west of Memphis, Tenn., into southern Illinois. Several times in the past century, moderate earthquakes have been widely felt in the Wabash Valley seismic zone along the southern border of Illinois and Indiana. Throughout the region, between 150 and 200 earthquakes are recorded annually by a network of monitoring instruments, although most are too small to be felt by people. Geologic evidence for prehistoric earthquakes throughout the region has been mounting since the late 1970s. But how significant is the threat? How likely are large earthquakes and, more importantly, what is the chance that the shaking they cause will be damaging?

  18. Mobile phone use for 5 minutes can cause significant memory impairment in humans.

    PubMed

    Kalafatakis, F; Bekiaridis-Moschou, D; Gkioka, Eirini; Tsolaki, Magda

    2017-01-01

    control group the second measurement was better than the first and the third even better than both previous ones. All differences were statistically significant. The reduction of the performance in the task after using the MP was even higher for the age group of 60-80 years old in comparison with younger age groups, as well as for the individuals with MCI in comparison to healthy participants. Age was significantly negative correlated with performance in the task, while gender showed no significant correlation. MP use has a significant negative impact on working memory performance of human participants. The effect is apparent even for a 5 minute use of the MP. Working memory deficits are greater not only for the 60 years old and above participants but also for individuals with Mild Cognitive Impairment. These results are in agreement with previous studies on animals as well as humans on the effects of MP use on the brain. It is argued that low sensitivity of some of the cognitive tasks used until now and the lack of a validated tool in the form of a cognitive task may account for some of the variability in the literature so far. It is suggested that the experimental paradigm that was used in this study for an increased sensitivity measurement of cognitive function and working memory processes in particular may be used for the display of the effects of MP use on cognitive function and for the development of other tasks sensitive to it. Overall, it is concluded that the development of certain restrictions on MP use is necessary for the protection of the brain health of the users.

  19. Silencing onion lachrymatory factor synthase causes a significant change in the sulfur secondary metabolite profile.

    PubMed

    Eady, Colin C; Kamoi, Takahiro; Kato, Masahiro; Porter, Noel G; Davis, Sheree; Shaw, Martin; Kamoi, Akiko; Imai, Shinsuke

    2008-08-01

    Through a single genetic transformation in onion (Allium cepa), a crop recalcitrant to genetic transformation, we suppressed the lachrymatory factor synthase gene using RNA interference silencing in six plants. This reduced lachrymatory synthase activity by up to 1,544-fold, so that when wounded the onions produced significantly reduced levels of tear-inducing lachrymatory factor. We then confirmed, through a novel colorimetric assay, that this silencing had shifted the trans-S-1-propenyl-l-cysteine sulfoxide breakdown pathway so that more 1-propenyl sulfenic acid was converted into di-1-propenyl thiosulfinate. A consequence of this raised thiosulfinate level was a marked increase in the downstream production of a nonenzymatically produced zwiebelane isomer and other volatile sulfur compounds, di-1-propenyl disulfide and 2-mercapto-3,4-dimethyl-2,3-dihydrothiophene, which had previously been reported in trace amounts or had not been detected in onion. The consequences of this dramatic simultaneous down- and up-regulation of secondary sulfur products on the health and flavor attributes of the onion are discussed.

  20. Significant Improvement in Chronic Persistent Headaches Caused by Small Rathke Cleft Cysts After Transsphenoidal Surgery.

    PubMed

    Fukui, Issei; Hayashi, Yasuhiko; Kita, Daisuke; Sasagawa, Yasuo; Oishi, Masahiro; Tachibana, Osamu; Nakada, Mitsutoshi

    2017-03-01

    Rathke cleft cysts (RCC) usually are asymptomatic and can be observed via the use of conservative methods. Some patients with RCCs, however, have severe headaches even if they are small enough to be confined to the sella, and these small RCCs seldom have been discussed. This study presents an investigation into clinical characteristics of small RCCs associated with severe headaches, demonstrating efficacy and safety of endoscopic transsphenoidal surgery (ETSS) to relieve headaches. In this study, 13 patients with small RCCs (maximum diameter <10 mm) who presented with headaches and were treated by ETSS at our institute from 2009 to 2014 were recruited. These RCCs were treated Headache Impact Test-6 (HIT-6) score was calculated both pre- and postoperatively to evaluate headache severity. All patients complained of severe headaches, which disturbed their daily life. Most headaches were nonpulsating and localized in the frontal area. Characteristically, 6 patients (46%) experienced severe headaches with sudden onset that continued chronically. HIT-6 score was 64 on average, meaning headaches affected daily life severely. After surgical decompression of the cyst, headache in all of the patients improved dramatically and HIT-6 score decreased significantly to 37, suggesting that headaches were diminished. No newly developed deficiencies of the anterior pituitary lobe function were detected. Postoperative occurrence of diabetes insipidus was found in 2 patients, both of which were transient. No recurring cysts were found. Severe headaches can develop from small RCCs. In the present study, ETSS was performed on such patients effectively and safely to relieve their headaches. Copyright © 2017 Elsevier Inc. All rights reserved.

  1. Extending earthquakes' reach through cascading.

    PubMed

    Marsan, David; Lengliné, Olivier

    2008-02-22

    Earthquakes, whatever their size, can trigger other earthquakes. Mainshocks cause aftershocks to occur, which in turn activate their own local aftershock sequences, resulting in a cascade of triggering that extends the reach of the initial mainshock. A long-lasting difficulty is to determine which earthquakes are connected, either directly or indirectly. Here we show that this causal structure can be found probabilistically, with no a priori model nor parameterization. Large regional earthquakes are found to have a short direct influence in comparison to the overall aftershock sequence duration. Relative to these large mainshocks, small earthquakes collectively have a greater effect on triggering. Hence, cascade triggering is a key component in earthquake interactions.

  2. Study of changes in the lineament structure, caused by earthquakes in South America by applying the lineament analysis to the Aster (Terra) satellite data

    NASA Astrophysics Data System (ADS)

    Arellano-Baeza, A. A.; Zverev, A. T.; Malinnikov, V. A.

    The region between Southern Peru and Northern Chile is one of the most seismically and volcanically active regions in South America. This is caused by a constant subduction of the South American Plate, converging with the Nazca Plate in the extreme North of Chile. We used the 15 and 30 m resolution satellite images, provided by the ASTER (VNIR and SWIR) instrument onboard the Terra satellite to study changes in the geological faults close to earthquake epicenters in southern Peru. Visible and infrared spectral bands were analysed using “The Lineament Extraction and Stripes Statistic Analysis” (LESSA) software package to examine changes in the lineament features and stripe density fields caused by seismic activity. We used the satellite images 128 and 48 days before and 73 days after a 5.2 Richter scale magnitude earthquake. The fact that the seasonal variations in the South of Peru and North of Chile are very small, and the vegetation is very limited, allowed us to establish substantial changes in the lineament and the stripe density field features. We develop a methodology that allows to evaluate the seismic risk in this region for the future.

  3. The size, distribution, and mobility of landslides caused by the 2015 Mw7.8 Gorkha earthquake, Nepal

    NASA Astrophysics Data System (ADS)

    Roback, Kevin; Clark, Marin K.; West, A. Joshua; Zekkos, Dimitrios; Li, Gen; Gallen, Sean F.; Chamlagain, Deepak; Godt, Jonathan W.

    2018-01-01

    Coseismic landslides pose immediate and prolonged hazards to mountainous communities, and provide a rare opportunity to study the effect of large earthquakes on erosion and sediment budgets. By mapping landslides using high-resolution satellite imagery, we find that the 25 April 2015 Mw7.8 Gorkha earthquake and aftershock sequence produced at least 25,000 landslides throughout the steep Himalayan Mountains in central Nepal. Despite early reports claiming lower than expected landslide activity, our results show that the total number, area, and volume of landslides associated with the Gorkha event are consistent with expectations, when compared to prior landslide-triggering earthquakes around the world. The extent of landsliding mimics the extent of fault rupture along the east-west trace of the Main Himalayan Thrust and increases eastward following the progression of rupture. In this event, maximum modeled Peak Ground Acceleration (PGA) and the steepest topographic slopes of the High Himalaya are not spatially coincident, so it is not surprising that landslide density correlates neither with PGA nor steepest slopes on their own. Instead, we find that the highest landslide density is located at the confluence of steep slopes, high mean annual precipitation, and proximity to the deepest part of the fault rupture from which 0.5-2 Hz seismic energy originated. We suggest that landslide density was determined by a combination of earthquake source characteristics, slope distributions, and the influence of precipitation on rock strength via weathering and changes in vegetation cover. Determining the relative contribution of each factor will require further modeling and better constrained seismic parameters, both of which are likely to be developed in the coming few years as post-event studies evolve. Landslide mobility, in terms of the ratio of runout distance to fall height, is comparable to small volume landslides in other settings, and landslide volume-runout scaling is

  4. The size, distribution, and mobility of landslides caused by the 2015 Mw7.8 Gorkha earthquake, Nepal

    USGS Publications Warehouse

    Roback, Kevin; Clark, Marin K.; West, A. Joshua; Zekkos, Dimitrios; Li, Gen; Gallen, Sean F.; Chamlagain, Deepak; Godt, Jonathan W.

    2018-01-01

    Coseismic landslides pose immediate and prolonged hazards to mountainous communities, and provide a rare opportunity to study the effect of large earthquakes on erosion and sediment budgets. By mapping landslides using high-resolution satellite imagery, we find that the 25 April 2015 Mw7.8 Gorkha earthquake and aftershock sequence produced at least 25,000 landslides throughout the steep Himalayan Mountains in central Nepal. Despite early reports claiming lower than expected landslide activity, our results show that the total number, area, and volume of landslides associated with the Gorkha event are consistent with expectations, when compared to prior landslide-triggering earthquakes around the world. The extent of landsliding mimics the extent of fault rupture along the east-west trace of the Main Himalayan Thrust and increases eastward following the progression of rupture. In this event, maximum modeled Peak Ground Acceleration (PGA) and the steepest topographic slopes of the High Himalaya are not spatially coincident, so it is not surprising that landslide density correlates neither with PGA nor steepest slopes on their own. Instead, we find that the highest landslide density is located at the confluence of steep slopes, high mean annual precipitation, and proximity to the deepest part of the fault rupture from which 0.5–2 Hz seismic energy originated. We suggest that landslide density was determined by a combination of earthquake source characteristics, slope distributions, and the influence of precipitation on rock strength via weathering and changes in vegetation cover. Determining the relative contribution of each factor will require further modeling and better constrained seismic parameters, both of which are likely to be developed in the coming few years as post-event studies evolve. Landslide mobility, in terms of the ratio of runout distance to fall height, is comparable to small volume landslides in other settings, and landslide volume-runout scaling

  5. Character and Significance of Surface Rupture Near the Intersection of the Denali and Totschunda Faults, M7.9 Denali Fault Earthquake, Alaska, November 3, 2002

    NASA Astrophysics Data System (ADS)

    Wallace, W. K.; Sherrod, B. L.; Dawson, T. E.

    2002-12-01

    Preliminary observations suggest that right-lateral strike-slip on the Denali fault is transferred to the Totschunda fault via an extensional bend in the Little Tok River valley. Most of the surface rupture during the Denali fault earthquake was along an east- to east-southeast striking, gently curved segment of the Denali fault. However, in the Little Tok River valley, rupture transferred to the southeast-striking Totschunda fault and continued to the southeast for another 75 km. West of the Little Tok River valley, 5-7 m of right-lateral slip and up to 2 m of vertical offset occurred on the main strand of the Denali fault, but no apparent displacement occurred on the Denali fault east of the valley. Rupture west of the intersection also occurred on multiple discontinuous strands parallel to and south of the main strand of the Denali fault. In the Little Tok River valley, the northern part of the Totschunda fault system consists of multiple discontinuous southeast-striking strands that are connected locally by south-striking stepover faults. Faults of the northern Totschunda system display 0-2.5 m of right-lateral slip and 0-2.75 m of vertical offset, with the largest vertical offset on a dominantly extensional stepover fault. The strands of the Totschunda system converge southeastward to a single strand that had up to 2 m of slip. Complex and discontinuous faulting may reflect in part the immaturity of the northern Totschunda system, which is known to be younger and have much less total slip than the Denali. The Totschunda fault forms an extensional bend relative to the dominantly right-lateral Denali fault to the west. The fault geometry and displacements at the intersection suggest that slip on the Denali fault during the earthquake was accommodated largely by extension in the northern Totschunda fault system, allowing a significant decrease in strike-slip relative to the Denali fault. Strands to the southwest in the area of the bend may represent shortcut

  6. 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.…

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

    NASA Astrophysics Data System (ADS)

    Yao, Y. B.; Chen, P.; Zhang, S.; Chen, J. J.; Yan, F.; Peng, W. F.

    2012-03-01

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

  8. 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. 

  9. Earthquakes, September-October 1993

    USGS Publications Warehouse

    Person, W.J.

    1993-01-01

    The fatalities in the United States were caused by two earthquakes in southern Oregon on September 21. These earthquakes, both with magnitude 6.0 and separated in time by about 2 hrs, led to the deaths of two people. One of these deaths was apparently due to a heart attack induced by the earthquake

  10. Introduction to the special issue on the 2004 Parkfield earthquake and the Parkfield earthquake prediction experiment

    USGS Publications Warehouse

    Harris, R.A.; Arrowsmith, J.R.

    2006-01-01

    The 28 September 2004 M 6.0 Parkfield earthquake, a long-anticipated event on the San Andreas fault, is the world's best recorded earthquake to date, with state-of-the-art data obtained from geologic, geodetic, seismic, magnetic, and electrical field networks. This has allowed the preearthquake and postearthquake states of the San Andreas fault in this region to be analyzed in detail. Analyses of these data provide views into the San Andreas fault that show a complex geologic history, fault geometry, rheology, and response of the nearby region to the earthquake-induced ground movement. Although aspects of San Andreas fault zone behavior in the Parkfield region can be modeled simply over geological time frames, the Parkfield Earthquake Prediction Experiment and the 2004 Parkfield earthquake indicate that predicting the fine details of future earthquakes is still a challenge. Instead of a deterministic approach, forecasting future damaging behavior, such as that caused by strong ground motions, will likely continue to require probabilistic methods. However, the Parkfield Earthquake Prediction Experiment and the 2004 Parkfield earthquake have provided ample data to understand most of what did occur in 2004, culminating in significant scientific advances.

  11. Missing great earthquakes

    USGS Publications Warehouse

    Hough, Susan E.

    2013-01-01

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

  12. A Study on distinguishing seismic waves caused by natural earthquakes and underground nuclear explosion within North Korean Context

    NASA Astrophysics Data System (ADS)

    Premlet, B.; Sabu, S.; Kamarudheen, R.; Subair, S.

    2017-12-01

    Since the first nuclear test on 15 July 1945 , there have been over 2,051 other weapon tests around the world . The waveforms of a natural earthquake which generates strong S waves and an underground explosion which is dominated by P waves were distinguished from the analysis of data corresponding to a 2005 M5.0 Earthquake and a 2016 North Korean nuclear test , both at similar distances from seismometer . Further differences between the seismograms were evaluated and successfully distinguished between the origins of the elastic waves through the data using Moment Tensor Solution using stations BJT , HIA and INCN . North Korea has developed a nuclear fuel cycle capability and has both plutonium and enriched uranium programs at Pyongyang . Seismic recordings of vertical ground motion at Global Seismographic Network station IC.MDJ of the 4 seismic events at Punggye-ri , North Korea , which occurred on the 9th of October 2006 , 25th of May 2009, 12th of February 2013 and on the 6th of January and 9th of September , 2016 were examined and the P waves of these seismic waves , which show very similar wave form , were inspected and compared to the seismic data of the latest underground nuclear test on the 3rd of September 2017 at 03:30 UTC at the same site which is many times more powerful than the previous tests . The country , which is the only nation to have tested nuclear weapons in this millennium , has successfully prevented the release of radioactive isotopes and hampered data collection but further studies were done using acoustic data which was analysed from sonograms of the 4 North Korean tests at station MDJ. The latest explosion data from 3rd September was also compared to 42 presumed underground explosions which occurred in China , India , the U.S.S.R , Iran , Turkey and recorded at Arkansas Seismic Network.

  13. 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.

  14. 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. 

  15. 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. 

  16. Acute Myocardial Infarction and Stress Cardiomyopathy following the Christchurch Earthquakes

    PubMed Central

    Chan, Christina; Elliott, John; Troughton, Richard; Frampton, Christopher; Smyth, David; Crozier, Ian; Bridgman, Paul

    2013-01-01

    Background Christchurch, New Zealand, was struck by 2 major earthquakes at 4:36am on 4 September 2010, magnitude 7.1 and at 12:51pm on 22 February 2011, magnitude 6.3. Both events caused widespread destruction. Christchurch Hospital was the region's only acute care hospital. It remained functional following both earthquakes. We were able to examine the effects of the 2 earthquakes on acute cardiac presentations. Methods Patients admitted under Cardiology in Christchurch Hospital 3 week prior to and 5 weeks following both earthquakes were analysed, with corresponding control periods in September 2009 and February 2010. Patients were categorised based on diagnosis: ST elevation myocardial infarction, Non ST elevation myocardial infarction, stress cardiomyopathy, unstable angina, stable angina, non cardiac chest pain, arrhythmia and others. Results There was a significant increase in overall admissions (p<0.003), ST elevation myocardial infarction (p<0.016), and non cardiac chest pain (p<0.022) in the first 2 weeks following the early morning September earthquake. This pattern was not seen after the early afternoon February earthquake. Instead, there was a very large number of stress cardiomyopathy admissions with 21 cases (95% CI 2.6–6.4) in 4 days. There had been 6 stress cardiomyopathy cases after the first earthquake (95% CI 0.44–2.62). Statistical analysis showed this to be a significant difference between the earthquakes (p<0.05). Conclusion The early morning September earthquake triggered a large increase in ST elevation myocardial infarction and a few stress cardiomyopathy cases. The early afternoon February earthquake caused significantly more stress cardiomyopathy. Two major earthquakes occurring at different times of day differed in their effect on acute cardiac events. PMID:23844213

  17. Acute myocardial infarction and stress cardiomyopathy following the Christchurch earthquakes.

    PubMed

    Chan, Christina; Elliott, John; Troughton, Richard; Frampton, Christopher; Smyth, David; Crozier, Ian; Bridgman, Paul

    2013-01-01

    Christchurch, New Zealand, was struck by 2 major earthquakes at 4:36 am on 4 September 2010, magnitude 7.1 and at 12:51 pm on 22 February 2011, magnitude 6.3. Both events caused widespread destruction. Christchurch Hospital was the region's only acute care hospital. It remained functional following both earthquakes. We were able to examine the effects of the 2 earthquakes on acute cardiac presentations. Patients admitted under Cardiology in Christchurch Hospital 3 week prior to and 5 weeks following both earthquakes were analysed, with corresponding control periods in September 2009 and February 2010. Patients were categorised based on diagnosis: ST elevation myocardial infarction, Non ST elevation myocardial infarction, stress cardiomyopathy, unstable angina, stable angina, non cardiac chest pain, arrhythmia and others. There was a significant increase in overall admissions (p<0.003), ST elevation myocardial infarction (p<0.016), and non cardiac chest pain (p<0.022) in the first 2 weeks following the early morning September earthquake. This pattern was not seen after the early afternoon February earthquake. Instead, there was a very large number of stress cardiomyopathy admissions with 21 cases (95% CI 2.6-6.4) in 4 days. There had been 6 stress cardiomyopathy cases after the first earthquake (95% CI 0.44-2.62). Statistical analysis showed this to be a significant difference between the earthquakes (p<0.05). The early morning September earthquake triggered a large increase in ST elevation myocardial infarction and a few stress cardiomyopathy cases. The early afternoon February earthquake caused significantly more stress cardiomyopathy. Two major earthquakes occurring at different times of day differed in their effect on acute cardiac events.

  18. Coping with earthquakes induced by fluid injection

    USGS Publications Warehouse

    McGarr, Arthur F.; Bekins, Barbara; Burkardt, Nina; Dewey, James W.; Earle, Paul S.; Ellsworth, William L.; Ge, Shemin; Hickman, Stephen H.; Holland, Austin F.; Majer, Ernest; Rubinstein, Justin L.; Sheehan, Anne

    2015-01-01

    Large areas of the United States long considered geologically stable with little or no detected seismicity have recently become seismically active. The increase in earthquake activity began in the mid-continent starting in 2001 (1) and has continued to rise. In 2014, the rate of occurrence of earthquakes with magnitudes (M) of 3 and greater in Oklahoma exceeded that in California (see the figure). This elevated activity includes larger earthquakes, several with M > 5, that have caused significant damage (2, 3). To a large extent, the increasing rate of earthquakes in the mid-continent is due to fluid-injection activities used in modern energy production (1, 4, 5). We explore potential avenues for mitigating effects of induced seismicity. Although the United States is our focus here, Canada, China, the UK, and others confront similar problems associated with oil and gas production, whereas quakes induced by geothermal activities affect Switzerland, Germany, and others.

  19. 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

  20. Earthquakes and emergence

    NASA Astrophysics Data System (ADS)

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

  1. 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.

  2. Post-Earthquake Reconstruction — in Context of Housing

    NASA Astrophysics Data System (ADS)

    Sarkar, Raju

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

  3. Earthquakes, September-October 1991

    USGS Publications Warehouse

    Person, W.J.

    1992-01-01

    There were two major earthquakes (7.0-7.9) during this reporting period. the first was in the Solomon Islands on October 14 and the second was in India on October 19. Earthquake-related deaths were reported in Guatemala and India. Htere were no significant earthquakes in the United States during the period covered in this report. 

  4. Coseismic displacement caused by the Mw 6.1 Mashhad earthquake in NE Iran from Sentinel-1A TOPS radar images

    NASA Astrophysics Data System (ADS)

    Su, Z.; Hu, J. C.; Talebian, M.

    2017-12-01

    Determining the relationship between crustal movement and associated slip partitioning is essential for understanding earthquake source and addressing the proposed models of a potential earthquake hazard. An Mw 6.1 earthquake struck the southeastern margin of the Mashhad valley in the northeast of Iran on 5 April 2017. In this study, we use both the ascending and descending mode of Sentinel-1A TOPS satellite data to characterize coseismic deformation pattern and to inverse the coseismic slip distribution on the fault patches. The best fitting model predicts that the coseismic rupture occurs along a fault plane with strike of 324.4º and dip of 28.1ºE. Our results show the fault tip does not propagate to the ground surface, and the predicted coseismic slip on the surface is about 0.11 m located on the hanging wall of the fault. Significant slip is concentrated on the fault patches at depth of 4-8 km and an along-strike distance of 10 km with varying slip magnitude from 0.1 m to 0.9 m. The fault slip is composed by thrusting with right-lateral strike slip, which is consistent with the focal mechanism solution. The over-thrusting was occurred from the depth of 14 km and terminated at the 4 km depth. While the right-lateral strike slip was only concentrated at a shallower depth of 4 to 8 km depth with the maximum slip of 0.9 m. The seismic moment release of our preferred fault model is 1.71×1018 Nm, equivalent to Mw 6.16 event. The Coulomb failure stress (CFS) calculated by the preferred fault model predicts significant positive CFS change on the three paralleled subsidiary faults of the southernmost Mashhad and Kashafrud fault, the Tus, Sorkhdeh and Natu faults. Consequently, these segments should be considered to have increasing of risk for future seismic hazard. Although most of the northward motion of the Lut and Central Iranian Blocks have been absorbed by the crustal shortening (e.g. thrusting and folding along the Binalud and Kopeh Dagh), simple strike

  5. On near-source earthquake triggering

    USGS Publications Warehouse

    Parsons, T.; Velasco, A.A.

    2009-01-01

    When one earthquake triggers others nearby, what connects them? Two processes are observed: static stress change from fault offset and dynamic stress changes from passing seismic waves. In the near-source region (r ??? 50 km for M ??? 5 sources) both processes may be operating, and since both mechanisms are expected to raise earthquake rates, it is difficult to isolate them. We thus compare explosions with earthquakes because only earthquakes cause significant static stress changes. We find that large explosions at the Nevada Test Site do not trigger earthquakes at rates comparable to similar magnitude earthquakes. Surface waves are associated with regional and long-range dynamic triggering, but we note that surface waves with low enough frequency to penetrate to depths where most aftershocks of the 1992 M = 5.7 Little Skull Mountain main shock occurred (???12 km) would not have developed significant amplitude within a 50-km radius. We therefore focus on the best candidate phases to cause local dynamic triggering, direct waves that pass through observed near-source aftershock clusters. We examine these phases, which arrived at the nearest (200-270 km) broadband station before the surface wave train and could thus be isolated for study. Direct comparison of spectral amplitudes of presurface wave arrivals shows that M ??? 5 explosions and earthquakes deliver the same peak dynamic stresses into the near-source crust. We conclude that a static stress change model can readily explain observed aftershock patterns, whereas it is difficult to attribute near-source triggering to a dynamic process because of the dearth of aftershocks near large explosions.

  6. 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. 

  7. Earthquake sources near Uturuncu Volcano

    NASA Astrophysics Data System (ADS)

    Keyson, L.; West, M. E.

    2013-12-01

    Uturuncu, located in southern Bolivia near the Chile and Argentina border, is a dacitic volcano that was last active 270 ka. It is a part of the Altiplano-Puna Volcanic Complex, which spans 50,000 km2 and is comprised of a series of ignimbrite flare-ups since ~23 ma. Two sets of evidence suggest that the region is underlain by a significant magma body. First, seismic velocities show a low velocity layer consistent with a magmatic sill below depths of 15-20 km. This inference is corroborated by high electrical conductivity between 10km and 30km. This magma body, the so called Altiplano-Puna Magma Body (APMB) is the likely source of volcanic activity in the region. InSAR studies show that during the 1990s, the volcano experienced an average uplift of about 1 to 2 cm per year. The deformation is consistent with an expanding source at depth. Though the Uturuncu region exhibits high rates of crustal seismicity, any connection between the inflation and the seismicity is unclear. We investigate the root causes of these earthquakes using a temporary network of 33 seismic stations - part of the PLUTONS project. Our primary approach is based on hypocenter locations and magnitudes paired with correlation-based relative relocation techniques. We find a strong tendency toward earthquake swarms that cluster in space and time. These swarms often last a few days and consist of numerous earthquakes with similar source mechanisms. Most seismicity occurs in the top 10 kilometers of the crust and is characterized by well-defined phase arrivals and significant high frequency content. The frequency-magnitude relationship of this seismicity demonstrates b-values consistent with tectonic sources. There is a strong clustering of earthquakes around the Uturuncu edifice. Earthquakes elsewhere in the region align in bands striking northwest-southeast consistent with regional stresses.

  8. Listening to the 2011 magnitude 9.0 Tohoku-Oki, Japan, earthquake

    USGS Publications Warehouse

    Peng, Zhigang; Aiken, Chastity; Kilb, Debi; Shelly, David R.; Enescu, Bogdan

    2012-01-01

    The magnitude 9.0 Tohoku-Oki, Japan, earthquake on 11 March 2011 is the largest earthquake to date in Japan’s modern history and is ranked as the fourth largest earthquake in the world since 1900. This earthquake occurred within the northeast Japan subduction zone (Figure 1), where the Pacific plate is subducting beneath the Okhotsk plate at rate of ∼8–9 cm/yr (DeMets et al. 2010). This type of extremely large earthquake within a subduction zone is generally termed a “megathrust” earthquake. Strong shaking from this magnitude 9 earthquake engulfed the entire Japanese Islands, reaching a maximum acceleration ∼3 times that of gravity (3 g). Two days prior to the main event, a foreshock sequence occurred, including one earthquake of magnitude 7.2. Following the main event, numerous aftershocks occurred around the main slip region; the largest of these was magnitude 7.9. The entire foreshocks-mainshock-aftershocks sequence was well recorded by thousands of sensitive seismometers and geodetic instruments across Japan, resulting in the best-recorded megathrust earthquake in history. This devastating earthquake resulted in significant damage and high death tolls caused primarily by the associated large tsunami. This tsunami reached heights of more than 30 m, and inundation propagated inland more than 5 km from the Pacific coast, which also caused a nuclear crisis that is still affecting people’s lives in certain regions of Japan.

  9. PAGER--Rapid assessment of an earthquake?s impact

    USGS Publications Warehouse

    Wald, D.J.; Jaiswal, K.; Marano, K.D.; Bausch, D.; Hearne, M.

    2010-01-01

    PAGER (Prompt Assessment of Global Earthquakes for Response) is an automated system that produces content concerning the impact of significant earthquakes around the world, informing emergency responders, government and aid agencies, and the media of the scope of the potential disaster. PAGER rapidly assesses earthquake impacts by comparing the population exposed to each level of shaking intensity with models of economic and fatality losses based on past earthquakes in each country or region of the world. Earthquake alerts--which were formerly sent based only on event magnitude and location, or population exposure to shaking--now will also be generated based on the estimated range of fatalities and economic losses.

  10. 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. 

  11. Slide-induced waves, seiching and ground fracturing caused by the earthquake of March 27, 1964 at Kenai Lake, Alaska: Chapter A in The Alaska earthquake, March 27, 1964: regional effects

    USGS Publications Warehouse

    McCulloch, David S.

    1966-01-01

    The March 27, 1964, earthquake dislodged slides from nine deltas in Kenai Lake, south-central Alaska. Sliding removed protruding parts of deltas-often the youngest parts-and steepened delta fronts, increasing the chances of further sliding. Fathograms show that debris from large slides spread widely over the lake floor, some reaching the toe of the opposite shore; at one place debris traveled 5,000 feet over the horizontal lake floor. Slides generated two kinds of local waves: a backfill and far-shore wave. Backfill waves were formed by water that rushed toward the delta to fill the void left by the sinking slide mass, overtopped the slide scrap, and came ashore over the delta. Some backfill waves had runup heights of 30 feet and ran inland more than 300 feet, uprooting and breaking off large trees. Far-shore waves hit the shore opposite the slides. They were formed by slide debris that crossed the lake floor and forced water ahead of it, which then ran up the opposite slope, burst above the lake surface, and struck the shore. One far-shore wave had a runup height of 72 feet. Kenai Lake was tilted and seiched; a power spectrum analysis of a limnogram shows a wave having the period of the calculated uninodal seiche (36 minutes) and several shorter period waves. In constricted and shallow reaches, waves caused by seiching had 20- and 30-foot runup heights. Deep lateral spreading of sediments toward delta margins displaced deeply driven railroad-bridge piles, and set up stress fields in the surface sediments which resulted in the formation of many shear and some tension fractures on the surface of two deltas.

  12. The 1909 Taipei earthquake: implication for seismic hazard in Taipei

    USGS Publications Warehouse

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

    2012-01-01

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

  13. 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.

  14. 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. 

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

    NASA Astrophysics Data System (ADS)

    Liu, B.

    2017-12-01

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

  16. Coseismic Stress Changes of the 2016 Mw 7.8 Kaikoura, New Zealand, Earthquake and Its Implication for Seismic Hazard Assessment

    NASA Astrophysics Data System (ADS)

    Shan, B.; LIU, C.; Xiong, X.

    2017-12-01

    On 13 November 2016, an earthquake with moment magnitude Mw 7.8 stroke North Canterbury, New Zealand as result of shallow oblique-reverse faulting close to boundary between the Pacific and Australian plates in the South Island, collapsing buildings and resulting in significant economic losses. The distribution of early aftershocks extended about 150 km to the north-northeast of the mainshock, suggesting the potential of earthquake triggering in this complex fault system. Strong aftershocks following major earthquakes present significant challenges for locals' reconstruction and rehabilitation. The regions around the mainshock may also suffer from earthquakes triggered by the Kaikoura earthquake. Therefore, it is significantly important to outline the regions with potential aftershocks and high seismic hazard to mitigate future disasters. Moreover, this earthquake ruptured at least 13 separate faults, and provided an opportunity to test the theory of earthquake stress triggering for a complex fault system. In this study, we calculated the coseismic Coulomb Failure Stress changes (ΔCFS) caused by the Kaikoura earthquake on the hypocenters of both historical earthquakes and aftershocks of this event with focal mechanisms. Our results show that the percentage of earthquake with positive ΔCFS within the aftershocks is higher than that of historical earthquakes. It means that the Kaikoura earthquake effectively influence the seismicity in this region. The aftershocks of Mw 7.8 Kaikoura earthquake are mainly located in the regions with positive ΔCFS. The aftershock distributions can be well explained by the coseismic ΔCFS. Furthermore, earthquake-induced ΔCFS on the surrounding active faults was further discussed. The northeastern Alpine fault, the southwest part of North Canterbury Fault, parts of the Marlborough fault system and the southwest ends of the Kapiti-Manawatu faults are significantly stressed by the Kaikoura earthquake. The earthquake-induced stress

  17. Earthquake chemical precursors in groundwater: a review

    NASA Astrophysics Data System (ADS)

    Paudel, Shukra Raj; Banjara, Sushant Prasad; Wagle, Amrita; Freund, Friedemann T.

    2018-03-01

    We review changes in groundwater chemistry as precursory signs for earthquakes. In particular, we discuss pH, total dissolved solids (TDS), electrical conductivity, and dissolved gases in relation to their significance for earthquake prediction or forecasting. These parameters are widely believed to vary in response to seismic and pre-seismic activity. However, the same parameters also vary in response to non-seismic processes. The inability to reliably distinguish between changes caused by seismic or pre-seismic activities from changes caused by non-seismic activities has impeded progress in earthquake science. Short-term earthquake prediction is unlikely to be achieved, however, by pH, TDS, electrical conductivity, and dissolved gas measurements alone. On the other hand, the production of free hydroxyl radicals (•OH), subsequent reactions such as formation of H2O2 and oxidation of As(III) to As(V) in groundwater, have distinctive precursory characteristics. This study deviates from the prevailing mechanical mantra. It addresses earthquake-related non-seismic mechanisms, but focused on the stress-induced electrification of rocks, the generation of positive hole charge carriers and their long-distance propagation through the rock column, plus on electrochemical processes at the rock-water interface.

  18. Selective Impact of Disease on Coral Communities: Outbreak of White Syndrome Causes Significant Total Mortality of Acropora Plate Corals

    PubMed Central

    Hobbs, Jean-Paul A.; Frisch, Ashley J.; Newman, Stephen J.; Wakefield, Corey B.

    2015-01-01

    Coral diseases represent a significant and increasing threat to coral reefs. Among the most destructive diseases is White Syndrome (WS), which is increasing in distribution and prevalence throughout the Indo-Pacific. The aim of this study was to determine taxonomic and spatial patterns in mortality rates of corals following the 2008 outbreak of WS at Christmas Island in the eastern Indian Ocean. WS mainly affected Acropora plate corals and caused total mortality of 36% of colonies across all surveyed sites and depths. Total mortality varied between sites but was generally much greater in the shallows (0–96% of colonies at 5 m depth) compared to deeper waters (0–30% of colonies at 20 m depth). Site-specific mortality rates were a reflection of the proportion of corals affected by WS at each site during the initial outbreak and were predicted by the initial cover of live Acropora plate cover. The WS outbreak had a selective impact on the coral community. Following the outbreak, live Acropora plate coral cover at 5 m depth decreased significantly from 7.0 to 0.8%, while the cover of other coral taxa remained unchanged. Observations five years after the initial outbreak revealed that total Acropora plate cover remained low and confirmed that corals that lost all their tissue due to WS did not recover. These results demonstrate that WS represents a significant and selective form of coral mortality and highlights the serious threat WS poses to coral reefs in the Indo-Pacific. PMID:26147291

  19. Far-field pressurization likely caused one of the largest injection induced earthquakes by reactivating a large pre-existing basement fault structure

    USGS Publications Warehouse

    Yeck, William; Weingarten, Matthew; Benz, Harley M.; McNamara, Daniel E.; Bergman, E.; Herrmann, R.B; Rubinstein, Justin L.; Earle, Paul

    2016-01-01

    The Mw 5.1 Fairview, Oklahoma, earthquake on 13 February 2016 and its associated seismicity produced the largest moment release in the central and eastern United States since the 2011 Mw 5.7 Prague, Oklahoma, earthquake sequence and is one of the largest earthquakes potentially linked to wastewater injection. This energetic sequence has produced five earthquakes with Mw 4.4 or larger. Almost all of these earthquakes occur in Precambrian basement on a partially unmapped 14 km long fault. Regional injection into the Arbuckle Group increased approximately sevenfold in the 36 months prior to the start of the sequence (January 2015). We suggest far-field pressurization from clustered, high-rate wells greater than 12 km from this sequence induced these earthquakes. As compared to the Fairview sequence, seismicity is diffuse near high-rate wells, where pressure changes are expected to be largest. This points to the critical role that preexisting faults play in the occurrence of large induced earthquakes.

  20. Shallow Geological Structures Triggered During the Mw6.4 Meinong Earthquake and Their Significance in Accommodating Long-term Shortening Across the Foothills of Southwestern Taiwan

    NASA Astrophysics Data System (ADS)

    Le Beon, M.; Suppe, J.; Huang, M. H.; Huang, S. T.; Ulum, H. H. M.; Ching, K. E.; Hsieh, Y. H.

    2017-12-01

    The 2016 Mw6.4 Meinong earthquake generated up to 10 cm surface displacement located 10-35 km W of the epicenter and monitored by InSAR and GPS. In addition to coseismic deformation related to the deep earthquake source, InSAR revealed three sharp surface displacement gradients that suggest slip triggering on shallow structures. To characterize these shallow structures, we build two EW regional balanced cross-sections, based on surface geology, subsurface data, and coseismic and interseismic geodetic data. From the Coastal Plain to the eastern edge of the coseismic deformation area, we propose a series of three active W-dipping back-thrusts: the Houchiali fault, the Napalin-Pitou back-thrust, and the Lungchuan back-thrust. They all root on the 3.5-4.0 km deep Tainan detachment located near the base of the 3-km-thick Plio-Pleistocene Gutingkeng mudstone. Further east, the detachment would ramp down to a 7-km-deep detachment, allowing the E-dipping Lungchuan thrust and Pingxi thrust to bring Miocene formations to the surface. Another ramp from 7 to 11-km depth, is expected further east to bring the slate belt to the surface. Coseismic surface deformation measurements suggest that, in addition to the deeper (15-20 km) main rupture plane, mostly the 4-7-km deep ramp, the Lungchuan back-thrust, and the Tainan detachment slipped aseismically during or right after the earthquake. Preliminary restorations show that the E-dipping Lungchuan thrust and Pingxi thrust consumed >10 km shortening each, while evidence for present-day tectonic activity remains to be found. By contrast, structures located west of the 4-7-km deep ramp accommodated all together <10 km shortening since 450 ka ago or less based on published nannostratigraphy, and they show numerous evidence of Late Quaternary and present-day activity. The restorations also allow connecting the 11-km-depth detachment to a main detachment level evidenced from a velocity inversion in the local tomography. By contrast, the

  1. 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. 

  2. Comparative study of earthquake-related and non-earthquake-related head traumas using multidetector computed tomography

    PubMed Central

    Chu, Zhi-gang; Yang, Zhi-gang; Dong, Zhi-hui; Chen, Tian-wu; Zhu, Zhi-yu; Shao, Heng

    2011-01-01

    OBJECTIVE: The features of earthquake-related head injuries may be different from those of injuries obtained in daily life because of differences in circumstances. We aim to compare the features of head traumas caused by the Sichuan earthquake with those of other common head traumas using multidetector computed tomography. METHODS: In total, 221 patients with earthquake-related head traumas (the earthquake group) and 221 patients with other common head traumas (the non-earthquake group) were enrolled in our study, and their computed tomographic findings were compared. We focused the differences between fractures and intracranial injuries and the relationships between extracranial and intracranial injuries. RESULTS: More earthquake-related cases had only extracranial soft tissue injuries (50.7% vs. 26.2%, RR = 1.9), and fewer cases had intracranial injuries (17.2% vs. 50.7%, RR = 0.3) compared with the non-earthquake group. For patients with fractures and intracranial injuries, there were fewer cases with craniocerebral injuries in the earthquake group (60.6% vs. 77.9%, RR = 0.8), and the earthquake-injured patients had fewer fractures and intracranial injuries overall (1.5±0.9 vs. 2.5±1.8; 1.3±0.5 vs. 2.1±1.1). Compared with the non-earthquake group, the incidences of soft tissue injuries and cranial fractures combined with intracranial injuries in the earthquake group were significantly lower (9.8% vs. 43.7%, RR = 0.2; 35.1% vs. 82.2%, RR = 0.4). CONCLUSION: As depicted with computed tomography, the severity of earthquake-related head traumas in survivors was milder, and isolated extracranial injuries were more common in earthquake-related head traumas than in non-earthquake-related injuries, which may have been the result of different injury causes, mechanisms and settings. PMID:22012045

  3. Long-period ground motions at near-regional distances caused by the PL wave from, inland earthquakes: Observation and numerical simulation of the 2004 Mid-Niigata, Japan, Mw6.6 earthquake

    NASA Astrophysics Data System (ADS)

    Furumura, T.; Kennett, B. L. N.

    2017-12-01

    We examine the development of large, long-period ground motions at near-regional distances (D=50-200 km) generated by the PL wave from large, shallow inland earthquakes, based on the analysis of strong motion records and finite-difference method (FDM) simulations of seismic wave propagation. PL wave can be represented as leaking modes of the crustal waveguide and are commonly observed at regional distances between 300 to 1000 km as a dispersed, long-period signal with a dominant period of about 20 s. However, observations of recent earthquakes at the dense K-NET and KiK-net strong motion networks in Japan demonstrate the dominance of the PL wave at near-regional (D=50-200 km) distances as, e.g., for the 2004 Mid Niigata, Japan, earthquake (Mw6.6; h=13 km). The observed PL wave signal between P and S wave shows a large, dispersed wave packet with dominant period of about T=4-10 s with amplitude almost comparable to or larger than the later arrival of the S and surface waves. Thus, the early arrivals of the long-period PL wave immediately after P wave can enhance resonance with large-scale constructions such as high-rise buildings and large oil-storage tanks etc. with potential for disaster. Such strong effects often occurred during the 2004 Mid Niigata earthquakes and other large earthquakes which occurred nearby the Kanto (Tokyo) basin. FDM simulation of seismic wave propagation employing realistic 3-D sedimentary structure models demonstrates the process by which the PL wave develops at near-regional distances from shallow, crustal earthquakes by constructive interference of the P wave in the long-period band. The amplitude of the PL wave is very sensitive to low-velocity structure in the near-surface. Lowered velocities help to develop large SV-to-P conversion and weaken the P-to-SV conversion at the free surface. Both effects enhance the multiple P reflections in the crustal waveguide and prevent the leakage of seismic energy into the mantle. However, a very

  4. Response of a 14-story Anchorage, Alaska, building in 2002 to two close earthquakes and two distant Denali fault earthquakes

    USGS Publications Warehouse

    Celebi, M.

    2004-01-01

    The recorded responses of an Anchorage, Alaska, building during four significant earthquakes that occurred in 2002 are studied. Two earthquakes, including the 3 November 2002 M7.9 Denali fault earthquake, with epicenters approximately 275 km from the building, generated long trains of long-period (>1 s) surface waves. The other two smaller earthquakes occurred at subcrustal depths practically beneath Anchorage and produced higher frequency motions. These two pairs of earthquakes have different impacts on the response of the building. Higher modes are more pronounced in the building response during the smaller nearby events. The building responses indicate that the close-coupling of translational and torsional modes causes a significant beating effect. It is also possible that there is some resonance occurring due to the site frequency being close to the structural frequency. Identification of dynamic characteristics and behavior of buildings can provide important lessons for future earthquake-resistant designs and retrofit of existing buildings. ?? 2004, Earthquake Engineering Research Institute.

  5. Potentially induced earthquakes in Oklahoma, USA: links between wastewater injection and the 2011 Mw 5.7 earthquake sequence

    USGS Publications Warehouse

    Keranen, Katie M.; Savage, Heather M.; Abers, Geoffrey A.; Cochran, Elizabeth S.

    2013-01-01

    Significant earthquakes are increasingly occurring within the continental interior of the United States, including five of moment magnitude (Mw) ≥ 5.0 in 2011 alone. Concurrently, the volume of fluid injected into the subsurface related to the production of unconventional resources continues to rise. Here we identify the largest earthquake potentially related to injection, an Mw 5.7 earthquake in November 2011 in Oklahoma. The earthquake was felt in at least 17 states and caused damage in the epicentral region. It occurred in a sequence, with 2 earthquakes of Mw 5.0 and a prolific sequence of aftershocks. We use the aftershocks to illuminate the faults that ruptured in the sequence, and show that the tip of the initial rupture plane is within ~200 m of active injection wells and within ~1 km of the surface; 30% of early aftershocks occur within the sedimentary section. Subsurface data indicate that fluid was injected into effectively sealed compartments, and we interpret that a net fluid volume increase after 18 yr of injection lowered effective stress on reservoir-bounding faults. Significantly, this case indicates that decades-long lags between the commencement of fluid injection and the onset of induced earthquakes are possible, and modifies our common criteria for fluid-induced events. The progressive rupture of three fault planes in this sequence suggests that stress changes from the initial rupture triggered the successive earthquakes, including one larger than the first.

  6. Do Earthquakes Shake Stock Markets?

    PubMed Central

    2015-01-01

    This paper examines how major earthquakes affected the returns and volatility of aggregate stock market indices in thirty-five financial markets over the last twenty years. Results show that global financial markets are resilient to shocks caused by earthquakes even if these are domestic. Our analysis reveals that, in a few instances, some macroeconomic variables and earthquake characteristics (gross domestic product per capita, trade openness, bilateral trade flows, earthquake magnitude, a tsunami indicator, distance to the epicenter, and number of fatalities) mediate the impact of earthquakes on stock market returns, resulting in a zero net effect. However, the influence of these variables is market-specific, indicating no systematic pattern across global capital markets. Results also demonstrate that stock market volatility is unaffected by earthquakes, except for Japan. PMID:26197482

  7. Do Earthquakes Shake Stock Markets?

    PubMed

    Ferreira, Susana; Karali, Berna

    2015-01-01

    This paper examines how major earthquakes affected the returns and volatility of aggregate stock market indices in thirty-five financial markets over the last twenty years. Results show that global financial markets are resilient to shocks caused by earthquakes even if these are domestic. Our analysis reveals that, in a few instances, some macroeconomic variables and earthquake characteristics (gross domestic product per capita, trade openness, bilateral trade flows, earthquake magnitude, a tsunami indicator, distance to the epicenter, and number of fatalities) mediate the impact of earthquakes on stock market returns, resulting in a zero net effect. However, the influence of these variables is market-specific, indicating no systematic pattern across global capital markets. Results also demonstrate that stock market volatility is unaffected by earthquakes, except for Japan.

  8. Estimation of Surface Deformation due to Pasni Earthquake Using SAR Interferometry

    NASA Astrophysics Data System (ADS)

    Ali, M.; Shahzad, M. I.; Nazeer, M.; Kazmi, J. H.

    2018-04-01

    Earthquake cause ground deformation in sedimented surface areas like Pasni and that is a hazard. Such earthquake induced ground displacements can seriously damage building structures. On 7 February 2017, an earthquake with 6.3 magnitudes strike near to Pasni. We have successfully distinguished widely spread ground displacements for the Pasni earthquake by using InSAR-based analysis with Sentinel-1 satellite C-band data. The maps of surface displacement field resulting from the earthquake are generated. Sentinel-1 Wide Swath data acquired from 9 December 2016 to 28 February 2017 was used to generate displacement map. The interferogram revealed the area of deformation. The comparison map of interferometric vertical displacement in different time period was treated as an evidence of deformation caused by earthquake. Profile graphs of interferogram were created to estimate the vertical displacement range and trend. Pasni lies in strong earthquake magnitude effected area. The major surface deformation areas are divided into different zones based on significance of deformation. The average displacement in Pasni is estimated about 250 mm. Maximum pasni area is uplifted by earthquake and maximum uplifting occurs was about 1200 mm. Some of areas was subsidized like the areas near to shoreline and maximum subsidence was estimated about 1500 mm. Pasni is facing many problems due to increasing sea water intrusion under prevailing climatic change where land deformation due to a strong earthquake can augment its vulnerability.

  9. Injection-induced earthquakes

    USGS Publications Warehouse

    Ellsworth, William L.

    2013-01-01

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

  10. Earthquake Hazards.

    ERIC Educational Resources Information Center

    Donovan, Neville

    1979-01-01

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

  11. On the use of SSTAs (Significant Sequences of TIR Anomalies) to activate Natural Time Analysis: a long term study on earthquakes (M>4) occurred in Greece during 2004-2013

    NASA Astrophysics Data System (ADS)

    Lisi, Mariano; Tramutoli, Valerio; Eleftheriou, Alexander; Filizzola, Carolina; Genzano, Nicola; Lacava, Teodosio; Paciello, Rossana; Pergola, Nicola; Vallianatos, Filippos

    2017-04-01

    Real-time integration of independent observations is expected to significantly improve our present capability of dynamically assess Seismic Hazard. Specific observations (e.g. anomaly in one parameter) can be used as a trigger (and/or to establish space/time constraints) for activating (implementing) the analysis on other independent parameters (e.g. b-value computation, Natural Time Analysis, on seismic data) whose systematic computation could result otherwise very computationally expensive or operationally impossible. In the present paper one of these parameters (the Earth's emitted radiation in the Thermal Infra-Red spectral region) has been used to activate the application of Natural Time Analysis of seismic data in order to verify possible improvements in the forecast of earthquakes (with M≥4) occurred in Greece during 2004-2013. The RST (Robust Satellite Technique) data analysis approach and RETIRA (Robust Estimator of TIR Anomalies) index were used to preliminarily define, and then to identify, Significant Sequences of TIR Anomalies (SSTAs) in 10 years (2004-2013) of daily TIR images acquired by the Spinning Enhanced Visible and Infrared Imager (SEVIRI) on board the Meteosat Second Generation (MSG) satellite. A previous paper showed that in the same period of time more than 93% of all identified SSTAs occurred in a pre-fixed space-time window around earthquakes time (30 days before up to 15 after) and epicenter (within 150 km or Dorbrovolsky distance) with a false positive rate smaller than 7%. In this paper a circular area around the barycenter of the observed Thermal Anomalies (and not just the convolution of them) has been used to define the area from which to collect seismic data required for Natural Time Analysis. Fifteen days prior the date of the first observed Significant Thermal Anomaly (STA) was the starting time used for collecting earthquakes from the catalog. The changes in the quality of earthquake forecast that were achieved by using each

  12. Analog earthquakes

    SciTech Connect

    Hofmann, R.B.

    1995-09-01

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

  13. Near-simultaneous great earthquakes at Tongan megathrust and outer rise in September 2009.

    PubMed

    Beavan, J; Wang, X; Holden, C; Wilson, K; Power, W; Prasetya, G; Bevis, M; Kautoke, R

    2010-08-19

    The Earth's largest earthquakes and tsunamis are usually caused by thrust-faulting earthquakes on the shallow part of the subduction interface between two tectonic plates, where stored elastic energy due to convergence between the plates is rapidly released. The tsunami that devastated the Samoan and northern Tongan islands on 29 September 2009 was preceded by a globally recorded magnitude-8 normal-faulting earthquake in the outer-rise region, where the Pacific plate bends before entering the subduction zone. Preliminary interpretation suggested that this earthquake was the source of the tsunami. Here we show that the outer-rise earthquake was accompanied by a nearly simultaneous rupture of the shallow subduction interface, equivalent to a magnitude-8 earthquake, that also contributed significantly to the tsunami. The subduction interface event was probably a slow earthquake with a rise time of several minutes that triggered the outer-rise event several minutes later. However, we cannot rule out the possibility that the normal fault ruptured first and dynamically triggered the subduction interface event. Our evidence comes from displacements of Global Positioning System stations and modelling of tsunami waves recorded by ocean-bottom pressure sensors, with support from seismic data and tsunami field observations. Evidence of the subduction earthquake in global seismic data is largely hidden because of the earthquake's slow rise time or because its ground motion is disguised by that of the normal-faulting event. Earthquake doublets where subduction interface events trigger large outer-rise earthquakes have been recorded previously, but this is the first well-documented example where the two events occur so closely in time and the triggering event might be a slow earthquake. As well as providing information on strain release mechanisms at subduction zones, earthquakes such as this provide a possible mechanism for the occasional large tsunamis generated at the Tonga

  14. Earthquake Risk Mitigation in the Tokyo Metropolitan area

    NASA Astrophysics Data System (ADS)

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

    2010-12-01

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

  15. OMG Earthquake! Can Twitter improve earthquake response?

    NASA Astrophysics Data System (ADS)

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

    2009-12-01

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

  16. Road Damage Following Earthquake

    NASA Technical Reports Server (NTRS)

    1989-01-01

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

  17. Data mining of atmospheric parameters associated with coastal earthquakes

    NASA Astrophysics Data System (ADS)

    Cervone, Guido

    Earthquakes are natural hazards that pose a serious threat to society and the environment. A single earthquake can claim thousands of lives, cause damages for billions of dollars, destroy natural landmarks and render large territories uninhabitable. Studying earthquakes and the processes that govern their occurrence, is of fundamental importance to protect lives, properties and the environment. Recent studies have shown that anomalous changes in land, ocean and atmospheric parameters occur prior to earthquakes. The present dissertation introduces an innovative methodology and its implementation to identify anomalous changes in atmospheric parameters associated with large coastal earthquakes. Possible geophysical mechanisms are discussed in view of the close interaction between the lithosphere, the hydrosphere and the atmosphere. The proposed methodology is a multi strategy data mining approach which combines wavelet transformations, evolutionary algorithms, and statistical analysis of atmospheric data to analyze possible precursory signals. One dimensional wavelet transformations and statistical tests are employed to identify significant singularities in the data, which may correspond to anomalous peaks due to the earthquake preparatory processes. Evolutionary algorithms and other localized search strategies are used to analyze the spatial and temporal continuity of the anomalies detected over a large area (about 2000 km2), to discriminate signals that are most likely associated with earthquakes from those due to other, mostly atmospheric, phenomena. Only statistically significant singularities occurring within a very short time of each other, and which tract a rigorous geometrical path related to the geological properties of the epicentral area, are considered to be associated with a seismic event. A program called CQuake was developed to implement and validate the proposed methodology. CQuake is a fully automated, real time semi-operational system, developed to

  18. Magnetic fields are causing small, but significant changes of the radiochromic EBT3 film response to 6 MV photons.

    PubMed

    Delfs, Björn; Schoenfeld, Andreas A; Poppinga, Daniela; Kapsch, Ralf-Peter; Jiang, Ping; Harder, Dietrich; Poppe, Björn; Looe, Hui Khee

    2018-01-31

    The optical density (OD) of EBT3 radiochromic films (Ashland Specialty Ingredients, Bridgewater, NJ, USA) exposed to absorbed doses to water up to D  =  20 Gy in magnetic fields of B  =  0.35 and 1.42 T was measured in the three colour channels of an Epson Expression 10000XL flatbed scanner. A 7 cm wide water phantom with fixed film holder was placed between the pole shoes of a constant-current electromagnet with variable field strength and was irradiated by a 6 MV photon beam whose axis was directed at right angles with the field lines. The doses at the film position at water depth 5 cm were measured with a calibrated ionization chamber when the magnet was switched off and were converted to the doses in presence of the magnetic field via the monitor units and by a Monte Carlo-calculated correction accounting for the slight change of the depth dose curves in magnetic fields. In the presence of the 0.35 and 1.42 T fields small negative changes of the OD values at given absorbed doses to water occurred and just significantly exceeded the uncertainty margin given by the stochastic and the uncorrected systematic deviations. This change can be described by a  +2.1% change of the dose values needed to produce a given optical density in the presence of a 1.42 T field. The thereby modified OD versus D function remained unchanged irrespective of whether the original short film side-the preference direction of the monomer crystals of the film-was directed parallel or orthogonal to the magnetic field. The 'orientation effect', the difference between the optical densities measured in the 'portrait' or 'landscape' film positions on the scanner bed caused by the reflection of polarised light in the scanner's mirror system, remained unaltered after EBT3 film exposure in magnetic fields. An independent optical bench investigation of EBT3 films exposed to doses of 10 and 20 Gy at 0.35 and 1.42 T showed that the direction of the electric vector of polarised

  19. Earthquakes, November-December 1991

    USGS Publications Warehouse

    Person, W.J.

    1992-01-01

    There were three major earthquakes (7.0-7.9) during the last two months of the year: a magntidue 7.0 on November 19 in Columbia, a magnitude 7.4 in the Kuril Islands on December 22, and a magnitude 7.1 in the South Sandwich Islands on December 27. Earthquake-related deaths were reported in Colombia, Yemen, and Iran. there were no significant earthquakes in the United States during this reporting period. 

  20. Machine Learning Seismic Wave Discrimination: Application to Earthquake Early Warning

    NASA Astrophysics Data System (ADS)

    Li, Zefeng; Meier, Men-Andrin; Hauksson, Egill; Zhan, Zhongwen; Andrews, Jennifer

    2018-05-01

    Performance of earthquake early warning systems suffers from false alerts caused by local impulsive noise from natural or anthropogenic sources. To mitigate this problem, we train a generative adversarial network (GAN) to learn the characteristics of first-arrival earthquake P waves, using 300,000 waveforms recorded in southern California and Japan. We apply the GAN critic as an automatic feature extractor and train a Random Forest classifier with about 700,000 earthquake and noise waveforms. We show that the discriminator can recognize 99.2% of the earthquake P waves and 98.4% of the noise signals. This state-of-the-art performance is expected to reduce significantly the number of false triggers from local impulsive noise. Our study demonstrates that GANs can discover a compact and effective representation of seismic waves, which has the potential for wide applications in seismology.

  1. 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.

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

    PubMed

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

    2015-01-01

    showed no significant differences. Major earthquakes of the similar magnitude can cause different injury mechanisms, traumatic conditions and complications in the wounded under different climate and geographic environment.When an earthquake occurs in a poor traffic area of high altitude and large temperature difference, early medical rescue, injury control and wounded evacuation as well as sufficient warmth retention and food supply are of vital significance.

  3. 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.

  4. Magnetic fields are causing small, but significant changes of the radiochromic EBT3 film response to 6 MV photons

    NASA Astrophysics Data System (ADS)

    Delfs, Björn; Schoenfeld, Andreas A.; Poppinga, Daniela; Kapsch, Ralf-Peter; Jiang, Ping; Harder, Dietrich; Poppe, Björn; Khee Looe, Hui

    2018-02-01

    The optical density (OD) of EBT3 radiochromic films (Ashland Specialty Ingredients, Bridgewater, NJ, USA) exposed to absorbed doses to water up to D  =  20 Gy in magnetic fields of B  =  0.35 and 1.42 T was measured in the three colour channels of an Epson Expression 10000XL flatbed scanner. A 7 cm wide water phantom with fixed film holder was placed between the pole shoes of a constant-current electromagnet with variable field strength and was irradiated by a 6 MV photon beam whose axis was directed at right angles with the field lines. The doses at the film position at water depth 5 cm were measured with a calibrated ionization chamber when the magnet was switched off and were converted to the doses in presence of the magnetic field via the monitor units and by a Monte Carlo-calculated correction accounting for the slight change of the depth dose curves in magnetic fields. In the presence of the 0.35 and 1.42 T fields small negative changes of the OD values at given absorbed doses to water occurred and just significantly exceeded the uncertainty margin given by the stochastic and the uncorrected systematic deviations. This change can be described by a  +2.1% change of the dose values needed to produce a given optical density in the presence of a 1.42 T field. The thereby modified OD versus D function remained unchanged irrespective of whether the original short film side—the preference direction of the monomer crystals of the film—was directed parallel or orthogonal to the magnetic field. The ‘orientation effect’, the difference between the optical densities measured in the ‘portrait’ or ‘landscape’ film positions on the scanner bed caused by the reflection of polarised light in the scanner’s mirror system, remained unaltered after EBT3 film exposure in magnetic fields. An independent optical bench investigation of EBT3 films exposed to doses of 10 and 20 Gy at 0.35 and 1.42 T showed that the direction of the electric

  5. 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. 

  6. Charles Darwin's earthquake reports

    NASA Astrophysics Data System (ADS)

    Galiev, Shamil

    2010-05-01

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

  7. 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.

  8. 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. 

  9. 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.

  10. Patient trends in orthopedic traumas and related disorders after tsunami caused by the Great East Japan Earthquake: An experience in the primary referral medical center.

    PubMed

    Matsuzawa, Gaku; Sano, Hirotaka; Ohnuma, Hideji; Tomiya, Akihito; Kuwahara, Yoshiyuki; Hashimoto, Chihiro; Imamura, Itaru; Ishibashi, Satoru; Kobayashi, Michio; Kobayashi, Masakazu; Ishii, Tadashi; Kaneda, Iwao; Itoi, Eiji

    2016-07-01

    In the Great East Japan Earthquake, the Japanese Red Cross Ishinomaki Hospital played an important role as a principal referral center within the Ishinomaki region, one of the most severely affected areas in eastern Japan. The present study describes the patient population, clinical characteristics, and time courses of the medical problems observed at this hospital. A retrospective survey of medical logs and records was conducted on the first 2 weeks after the earthquake to characterize orthopedic traumas and related disorders treated during this catastrophe. Patient number, severity of injuries, number of patients secondarily transported to the referral medical centers in the inland area, and the number of surgeries performed during the study period were investigated. Totally, 7686 patients visited the hospital. Of which, 1807 patients suffered from exogenous diseases, such as trauma, burns, crush syndrome, deep venous thrombosis, and infectious diseases. Patients who suffered from hypothermia were the most frequently seen within the first 2 weeks after the earthquake. Interestingly, most patients' conditions were not severe and required only simple treatments. Four patients (0.2% of patients with exogenous diseases) were secondarily transported to the referral medical centers in the inland area and only four patients were surgically treated because of a lack of available implants, surgical devices, and electric power supply. The Great East Japan Earthquake and subsequent tsunami, which occurred during an early spring afternoon, resulted in a unique orthopedic patient population, which included few severely injured patients compared with numerous deaths. We believe that each coastal region hospital should develop its own emergency medical care system to address future tsunami events while considering their surrounding environment. The information described in the present study should be important for preparation toward future events involving massive earthquakes

  11. Earthquake Facts

    MedlinePlus

    ... recordings of large earthquakes, scientists built large spring-pendulum seismometers in an attempt to record the long- ... are moving away from one another. The first “pendulum seismoscope” to measure the shaking of the ground ...

  12. The 1999 Izmit, Turkey, earthquake: A 3D dynamic stress transfer model of intraearthquake triggering

    USGS Publications Warehouse

    Harris, R.A.; Dolan, J.F.; Hartleb, R.; Day, S.M.

    2002-01-01

    Before the August 1999 Izmit (Kocaeli), Turkey, earthquake, theoretical studies of earthquake ruptures and geological observations had provided estimates of how far an earthquake might jump to get to a neighboring fault. Both numerical simulations and geological observations suggested that 5 km might be the upper limit if there were no transfer faults. The Izmit earthquake appears to have followed these expectations. It did not jump across any step-over wider than 5 km and was instead stopped by a narrower step-over at its eastern end and possibly by a stress shadow caused by a historic large earthquake at its western end. Our 3D spontaneous rupture simulations of the 1999 Izmit earthquake provide two new insights: (1) the west- to east-striking fault segments of this part of the North Anatolian fault are oriented so as to be low-stress faults and (2) the easternmost segment involved in the August 1999 rupture may be dipping. An interesting feature of the Izmit earthquake is that a 5-km-long gap in surface rupture and an adjacent 25° restraining bend in the fault zone did not stop the earthquake. The latter observation is a warning that significant fault bends in strike-slip faults may not arrest future earthquakes.

  13. Mid-arm muscle circumference as a significant predictor of all-cause mortality in male individuals

    PubMed Central

    Wu, Li-Wei; Lin, Yuan-Yung; Kao, Tung-Wei; Lin, Chien-Ming; Liaw, Fang-Yih; Wang, Chung-Ching; Peng, Tao-Chun; Chen, Wei-Liang

    2017-01-01

    Background Emerging evidences indicate that mid-arm muscle circumference (MAMC) is one of the anthropometric indicators that reflect health and nutritional status, but its correlative effectiveness in all-cause mortality prediction of United States individuals remains uncertain. Methods and findings design We investigated the joint association between MAMC and all-cause mortality in the US general population. A population-based longitudinal study of 6,769 participants aged 40 to 90 years in the third National Health and Nutrition Examination Survey (NHANES III) conducted by the National Center for Health Statistics of the Centers for Disease Control and Prevention. All participants were divided into two groups based on the gender: male and female group; each group was then divided into three subgroups depending on their MAMC level. The tertiles were as follows: T1 (18<27.3), T2 (27.3<29.6), T3 (29.6≤40.0) cm in the male group and T1 (15<22.3), T2 (22.3<24.6), T3 (24.6≤44.0) cm in the female group. Multivariable Cox regression analyses and Kaplan–Meier survival probabilities were utilized to jointly relate all-cause mortality risk to different MAMC level. For all-cause mortality in male participants, multivariable adjusted hazard ratios (HRs) were 0.83 (95% confidence interval (CI): 0.69–0.98; p = 0.033) for MAMC of 27.3–29.6 cm compared with 18–27.3 cm, and 0.76 (95% CI: 0.61–0.95; p = 0.018) for MAMC of 29.6–40 cm compared with 18–27.3 cm. For all-cause mortality in female participants, multivariable adjusted hazard ratios (HRs) were 0.84 (95% confidence interval (CI): 0.69–1.02; p = 0.075) for MAMC of 22.3–24.6 cm compared with 15–22.3 cm, and 0.94 (95% CI: 0.75–1.17; p = 0.583) for MAMC of 24.6–44 cm compared with 15–22.3 cm. Conclusion Results support a lower MAMC is associated with a higher mortality risk in male individuals. PMID:28196081

  14. Earthquake watch

    USGS Publications Warehouse

    Hill, M.

    1976-01-01

     When the time comes that earthquakes can be predicted accurately, what shall we do with the knowledge? This was the theme of a November 1975 conference on earthquake warning and response held in San Francisco called by Assistant Secretary of the Interior Jack W. Carlson. Invited were officials of State and local governments from Alaska, California, Hawaii, Idaho, Montana, Nevada, utah, Washington, and Wyoming and representatives of the news media. 

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

    USGS Publications Warehouse

    Jones, Lucile M.

    1994-01-01

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

  16. 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

  17. 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.

  18. Earthquake Simulator Finds Tremor Triggers

    ScienceCinema

    Johnson, Paul

    2018-01-16

    Using a novel device that simulates earthquakes in a laboratory setting, a Los Alamos researcher has found that seismic waves-the sounds radiated from earthquakes-can induce earthquake aftershocks, often long after a quake has subsided. The research provides insight into how earthquakes may be triggered and how they recur. Los Alamos researcher Paul Johnson and colleague Chris Marone at Penn State have discovered how wave energy can be stored in certain types of granular materials-like the type found along certain fault lines across the globe-and how this stored energy can suddenly be released as an earthquake when hit by relatively small seismic waves far beyond the traditional “aftershock zone” of a main quake. Perhaps most surprising, researchers have found that the release of energy can occur minutes, hours, or even days after the sound waves pass; the cause of the delay remains a tantalizing mystery.

  19. Global earthquake casualties due to secondary effects: A quantitative analysis for improving rapid loss analyses

    USGS Publications Warehouse

    Marano, K.D.; Wald, D.J.; Allen, T.I.

    2010-01-01

    This study presents a quantitative and geospatial description of global losses due to earthquake-induced secondary effects, including landslide, liquefaction, tsunami, and fire for events during the past 40 years. These processes are of great importance to the US Geological Survey's (USGS) Prompt Assessment of Global Earthquakes for Response (PAGER) system, which is currently being developed to deliver rapid earthquake impact and loss assessments following large/significant global earthquakes. An important question is how dominant are losses due to secondary effects (and under what conditions, and in which regions)? Thus, which of these effects should receive higher priority research efforts in order to enhance PAGER's overall assessment of earthquakes losses and alerting for the likelihood of secondary impacts? We find that while 21.5% of fatal earthquakes have deaths due to secondary (non-shaking) causes, only rarely are secondary effects the main cause of fatalities. The recent 2004 Great Sumatra-Andaman Islands earthquake is a notable exception, with extraordinary losses due to tsunami. The potential for secondary hazards varies greatly, and systematically, due to regional geologic and geomorphic conditions. Based on our findings, we have built country-specific disclaimers for PAGER that address potential for each hazard (Earle et al., Proceedings of the 14th World Conference of the Earthquake Engineering, Beijing, China, 2008). We will now focus on ways to model casualties from secondary effects based on their relative importance as well as their general predictability. ?? Springer Science+Business Media B.V. 2009.

  20. Earthquakes for Kids

    MedlinePlus

    ... across a fault to learn about past earthquakes. Science Fair Projects A GPS instrument measures slow movements of the ground. Become an Earthquake Scientist Cool Earthquake Facts Today in Earthquake History A scientist stands in ...

  1. Measuring the size of an earthquake

    USGS Publications Warehouse

    Spence, W.

    1977-01-01

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

  2. Improvement Rate of Acute Otitis Media Caused by Haemophilus influenzae at 1 Week Is Significantly Associated with Time to Recovery

    PubMed Central

    Yamazaki, Yoshitaka; Qin, Liang; Okitsu, Naohiro; Yahara, Koji; Irimada, Mihoko; Hirakata, Yoichi; Kaku, Mitsuo; Kobayashi, Toshimitsu; Watanabe, Hiroshi

    2013-01-01

    Acute otitis media (AOM) is the most common upper respiratory tract infection in childhood. Children with AOM were enrolled at Tohoku Rosai Hospital between July 2006 and June 2011 if their middle ear fluid cultures after tympanocentesis yielded only Haemophilus influenzae. The susceptibilities of the isolates to ampicillin were determined, and microtiter biofilm assays and invasion assays using BEAS-2B cells were performed. The association between these bacterial characteristics and clinical relapses of AOM and treatment failures was evaluated. Seventy-four children (39 boys and 35 girls) with a median age of 1 year (interquartile range [IQR], 0.25 to 2 years) were enrolled. Among 74 H. influenzae isolates, 37 showed intermediate resistance or resistance to ampicillin (MIC, ≥2 μg/ml). In the microtiter biofilm assay, the median optical density at 600 nm (OD600) was 0.68 (IQR, 0.24 to 1.02), and 70 isolates formed biofilms. The median invasion rate was 15% (IQR, 0 to 10%), and 46 isolates invaded BEAS-2B cells. Relapses and treatment failures occurred in 19 and 6 children, respectively. There was no significant difference in the invasion rates between patients with and those without relapses or treatment failures. Also, there was no significant association between biofilm formation and relapse or treatment failure. The improvements in the severity scores after 1 week were significantly associated with the recovery time (P < 0.0001). We did not identify any significant association between relapse or treatment failure and bacterial factors. AOM has a multifactorial etiology, and this may explain why we could not find a significant association. An improvement in the severity score after 1 week of treatment may be a useful predictor of the outcome of AOM. PMID:23966504

  3. 88 hours: the U.S. Geological Survey National Earthquake Information Center response to the March 11, 2011 Mw 9.0 Tohoku earthquake

    USGS Publications Warehouse

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

    2011-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2014-12-01

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

  5. Comparison of Structurally Controlled Landslide Hazard Simulation to the Co-seismic Landslides Caused by the M 7.2 2013 Bohol Earthquake.

    NASA Astrophysics Data System (ADS)

    Galang, J. A. M. B.; Eco, R. C.; Lagmay, A. M. A.

    2014-12-01

    The M_w 7.2 October 15, 2013 Bohol earthquake is one of the more destructive earthquake to hit the Philippines in the 21st century. The epicenter was located in Sagbayan municipality, central Bohol and was generated by a previously unmapped reverse fault called the "Inabanga Fault". The earthquake resulted in 209 fatalities and over 57 million USD worth of damages. The earthquake generated co-seismic landslides most of which were related to fault structures. Unlike rainfall induced landslides, the trigger for co-seismic landslides happen without warning. Preparations for this type of landslides rely heavily on the identification of fracture-related slope instability. To mitigate the impacts of co-seismic landslide hazards, morpho-structural orientations of discontinuity sets were mapped using remote sensing techniques with the aid of a Digital Terrain Model (DTM) obtained in 2012. The DTM used is an IFSAR derived image with a 5-meter pixel resolution and approximately 0.5 meter vertical accuracy. Coltop 3D software was then used to identify similar structures including measurement of their dip and dip directions. The chosen discontinuity sets were then keyed into Matterocking software to identify potential rock slide zones due to planar or wedged discontinuities. After identifying the structurally-controlled unstable slopes, the rock mass propagation extent of the possible rock slides was simulated using Conefall. Separately, a manually derived landslide inventory has been performed using post-earthquake satellite images and LIDAR. The results were compared to the landslide inventory which identified at least 873 landslides. Out of the 873 landslides identified through the inventory, 786 or 90% intersect the simulated structural-controlled landslide hazard areas of Bohol. The results show the potential of this method to identify co-seismic landslide hazard areas for disaster mitigation. Along with computer methods to simulate shallow landslides, and debris flow

  6. Delayed flood recession in central Yangtze floodplains can cause significant food shortages for wintering geese: results of inundation experiment.

    PubMed

    Guan, Lei; Wen, Li; Feng, Duoduo; Zhang, Hong; Lei, Guangchun

    2014-12-01

    Carex meadows are critical habitat for wintering geese in the floodplains of the middle and lower reaches of Yangtze River, China. These meadows follow a growth cycle closely tied to the seasonal hydrological fluctuation: as water levels recede in the fall, exposed mudflats provide habitat for Carex spp. growth. The seasonal growth of Carex overlaps the arrival of wintering geese and provides an important food source for the migrants. Recent alterations to the Yangtze's hydrology, however, have disrupted the synchronous relationship between water levels, Carex growth and wintering geese at Dongting Lake. In October 2012, we carried out an outdoor mesocosm experiment to investigate potential impacts of delayed water recession on the germination and growth of Carex heterolepis, the dominant Carex species at Dongting Lake, to understand how changes in hydrology might impact wintering goose habitat. Results showed that the delayed flood recession exerted significant impact on the first growth cycle of Carex growth. Prolonged inundation significantly lowered the intrinsic growth rate (P = 0.03) and maximum growth rates (P = 0.02). It also took significantly longer time to reach the peak growth rate (P = 0.04 and 0.05 for number of shoot and biomass, respectively). As a result, biomass accumulation was reduced by 45, 62 and 90 % for 10-day, 20-day and 30-day inundation treatments, respectively. These results indicate a severe risk of food shortage for wintering geese when water recession delayed. This potential risk should be taken into consideration when operating any hydrological control structures that alter the flood regimes in Dongting Lake.

  7. 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.

  8. On the Diurnal Periodicity of Representative Earthquakes in Greece: Comparison of Data from Different Observation Systems

    NASA Astrophysics Data System (ADS)

    Desherevskii, A. V.; Sidorin, A. Ya.

    2017-12-01

    Due to the initiation of the Hellenic Unified Seismic Network (HUSN) in late 2007, the quality of observation significantly improved by 2011. For example, the representative magnitude level considerably has decreased and the number of annually recorded events has increased. The new observational system highly expanded the possibilities for studying regularities in seismicity. In view of this, the authors revisited their studies of the diurnal periodicity of representative earthquakes in Greece that was revealed earlier in the earthquake catalog before 2011. We use 18 samples of earthquakes of different magnitudes taken from the catalog of Greek earthquakes from 2011 to June 2016 to derive a series of the number of earthquakes for each of them and calculate its average diurnal course. To increase the reliability of the results, we compared the data for two regions. With a high degree of statistical significance, we have obtained that no diurnal periodicity can be found for strongly representative earthquakes. This finding differs from the estimates obtained earlier from an analysis of the catalog of earthquakes at the same area for 1995-2004 and 2005-2010, i.e., before the initiation of the Hellenic Unified Seismic Network. The new results are consistent with the hypothesis of noise discrimination (observational selection) explaining the cause of the diurnal variation of earthquakes with different sensitivity of the seismic network in daytime and nighttime periods.

  9. Chronic exposure to 50Hz magnetic fields causes a significant weakening of antioxidant defence systems in aged rat brain.

    PubMed

    Falone, Stefano; Mirabilio, Alessandro; Carbone, Maria Cristina; Zimmitti, Vincenzo; Di Loreto, Silvia; Mariggiò, Maria Addolorata; Mancinelli, Rosa; Di Ilio, Carmine; Amicarelli, Fernanda

    2008-01-01

    Several studies suggest that extremely low-frequency magnetic fields (ELF-MFs) may enhance the free radical endogenous production. It is also well known that one of the unavoidable consequences of ageing is an overall oxidative stress-based decline in several physiological functions and in the general resistance to stressors. On the basis of these assumptions, the aim of this study was to establish whether the ageing process can increase susceptibility towards widely present ELF-MF-mediated pro-oxidative challenges. To this end, female Sprague-Dawley rats were continuously exposed to a sinusoidal 50 Hz, 0.1 mT magnetic field for 10 days. Treatment-induced changes in the major antioxidant protection systems and in the neurotrophic support were investigated, as a function of the age of the subjects. All analyses were performed in brain cortices, due to the high susceptibility of neuronal cells to oxidative injury. Our results indicated that ELF-MF exposure significantly affects anti-oxidative capability, both in young and aged animals, although in opposite ways. Indeed, exposed young individuals enhanced their neurotrophic signalling and anti-oxidative enzymatic defence against a possible ELF-MF-mediated increase in oxygen radical species. In contrast, aged subjects were not capable of increasing their defences in response to ELF-MF treatment but, on the contrary, they underwent a significant decrease in the major antioxidant enzymatic activities. In conclusion, our data seem to suggest that the exposure to ELF-MFs may act as a risk factor for the occurrence of oxidative stress-based nervous system pathologies associated with ageing.

  10. Preliminary Study on Earthquake Surface Rupture Extraction from Uav Images

    NASA Astrophysics Data System (ADS)

    Yuan, X.; Wang, X.; Ding, X.; Wu, X.; Dou, A.; Wang, S.

    2018-04-01

    Because of the advantages of low-cost, lightweight and photography under the cloud, UAVs have been widely used in the field of seismic geomorphology research in recent years. Earthquake surface rupture is a typical seismic tectonic geomorphology that reflects the dynamic and kinematic characteristics of crustal movement. The quick identification of earthquake surface rupture is of great significance for understanding the mechanism of earthquake occurrence, disasters distribution and scale. Using integrated differential UAV platform, series images were acquired with accuracy POS around the former urban area (Qushan town) of Beichuan County as the area stricken seriously by the 2008 Wenchuan Ms8.0 earthquake. Based on the multi-view 3D reconstruction technique, the high resolution DSM and DOM are obtained from differential UAV images. Through the shade-relief map and aspect map derived from DSM, the earthquake surface rupture is extracted and analyzed. The results show that the surface rupture can still be identified by using the UAV images although the time of earthquake elapse is longer, whose middle segment is characterized by vertical movement caused by compression deformation from fault planes.

  11. Pressurized Martian-Like Pure CO2 Atmosphere Supports Strong Growth of Cyanobacteria, and Causes Significant Changes in their Metabolism

    NASA Astrophysics Data System (ADS)

    Murukesan, Gayathri; Leino, Hannu; Mäenpää, Pirkko; Ståhle, Kurt; Raksajit, Wuttinun; Lehto, Harry J.; Allahverdiyeva-Rinne, Yagut; Lehto, Kirsi

    2016-03-01

    Surviving of crews during future missions to Mars will depend on reliable and adequate supplies of essential life support materials, i.e. oxygen, food, clean water, and fuel. The most economical and sustainable (and in long term, the only viable) way to provide these supplies on Martian bases is via bio-regenerative systems, by using local resources to drive oxygenic photosynthesis. Selected cyanobacteria, grown in adequately protective containment could serve as pioneer species to produce life sustaining substrates for higher organisms. The very high (95.3 %) CO2 content in Martian atmosphere would provide an abundant carbon source for photo-assimilation, but nitrogen would be a strongly limiting substrate for bio-assimilation in this environment, and would need to be supplemented by nitrogen fertilizing. The very high supply of carbon, with rate-limiting supply of nitrogen strongly affects the growth and the metabolic pathways of the photosynthetic organisms. Here we show that modified, Martian-like atmospheric composition (nearly 100 % CO2) under various low pressure conditions (starting from 50 mbar to maintain liquid water, up to 200 mbars) supports strong cellular growth. Under high CO2 / low N2 ratio the filamentous cyanobacteria produce significant amount of H2 during light due to differentiation of high amount of heterocysts.

  12. Silencing Onion Lachrymatory Factor Synthase Causes a Significant Change in the Sulfur Secondary Metabolite Profile1[W][OA

    PubMed Central

    Eady, Colin C.; Kamoi, Takahiro; Kato, Masahiro; Porter, Noel G.; Davis, Sheree; Shaw, Martin; Kamoi, Akiko; Imai, Shinsuke

    2008-01-01

    Through a single genetic transformation in onion (Allium cepa), a crop recalcitrant to genetic transformation, we suppressed the lachrymatory factor synthase gene using RNA interference silencing in six plants. This reduced lachrymatory synthase activity by up to 1,544-fold, so that when wounded the onions produced significantly reduced levels of tear-inducing lachrymatory factor. We then confirmed, through a novel colorimetric assay, that this silencing had shifted the trans-S-1-propenyl-l-cysteine sulfoxide breakdown pathway so that more 1-propenyl sulfenic acid was converted into di-1-propenyl thiosulfinate. A consequence of this raised thiosulfinate level was a marked increase in the downstream production of a nonenzymatically produced zwiebelane isomer and other volatile sulfur compounds, di-1-propenyl disulfide and 2-mercapto-3,4-dimethyl-2,3-dihydrothiophene, which had previously been reported in trace amounts or had not been detected in onion. The consequences of this dramatic simultaneous down- and up-regulation of secondary sulfur products on the health and flavor attributes of the onion are discussed. PMID:18583530

  13. Spaceflight and simulated microgravity cause a significant reduction of key gene expression in early T-cell activation

    PubMed Central

    Martinez, Emily M.; Yoshida, Miya C.; Candelario, Tara Lynne T.

    2015-01-01

    Healthy immune function depends on precise regulation of lymphocyte activation. During the National Aeronautics and Space Administration (NASA) Apollo and Shuttle eras, multiple spaceflight studies showed depressed lymphocyte activity under microgravity (μg) conditions. Scientists on the ground use two models of simulated μg (sμg): 1) the rotating wall vessel (RWV) and 2) the random positioning machine (RPM), to study the effects of altered gravity on cell function before advancing research to the true μg when spaceflight opportunities become available on the International Space Station (ISS). The objective of this study is to compare the effects of true μg and sμg on the expression of key early T-cell activation genes in mouse splenocytes from spaceflight and ground animals. For the first time, we compared all three conditions of microgravity spaceflight, RPM, and RWV during immune gene activation of Il2, Il2rα, Ifnγ, and Tagap; moreover, we confirm two new early T-cell activation genes, Iigp1 and Slamf1. Gene expression for all samples was analyzed using quantitative real-time PCR (qRT-PCR). Our results demonstrate significantly increased gene expression in activated ground samples with suppression of mouse immune function in spaceflight, RPM, and RWV samples. These findings indicate that sμg models provide an excellent test bed for scientists to develop baseline studies and augment true μg in spaceflight experiments. Ultimately, sμg and spaceflight studies in lymphocytes may provide insight into novel regulatory pathways, benefiting both future astronauts and those here on earth suffering from immune disorders. PMID:25568077

  14. Spaceflight and simulated microgravity cause a significant reduction of key gene expression in early T-cell activation.

    PubMed

    Martinez, Emily M; Yoshida, Miya C; Candelario, Tara Lynne T; Hughes-Fulford, Millie

    2015-03-15

    Healthy immune function depends on precise regulation of lymphocyte activation. During the National Aeronautics and Space Administration (NASA) Apollo and Shuttle eras, multiple spaceflight studies showed depressed lymphocyte activity under microgravity (μg) conditions. Scientists on the ground use two models of simulated μg (sμg): 1) the rotating wall vessel (RWV) and 2) the random positioning machine (RPM), to study the effects of altered gravity on cell function before advancing research to the true μg when spaceflight opportunities become available on the International Space Station (ISS). The objective of this study is to compare the effects of true μg and sμg on the expression of key early T-cell activation genes in mouse splenocytes from spaceflight and ground animals. For the first time, we compared all three conditions of microgravity spaceflight, RPM, and RWV during immune gene activation of Il2, Il2rα, Ifnγ, and Tagap; moreover, we confirm two new early T-cell activation genes, Iigp1 and Slamf1. Gene expression for all samples was analyzed using quantitative real-time PCR (qRT-PCR). Our results demonstrate significantly increased gene expression in activated ground samples with suppression of mouse immune function in spaceflight, RPM, and RWV samples. These findings indicate that sμg models provide an excellent test bed for scientists to develop baseline studies and augment true μg in spaceflight experiments. Ultimately, sμg and spaceflight studies in lymphocytes may provide insight into novel regulatory pathways, benefiting both future astronauts and those here on earth suffering from immune disorders.

  15. Earthquake impact scale

    USGS Publications Warehouse

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

    2011-01-01

    also be both specific (although allowably uncertain) and actionable. In this analysis, an attempt is made at both simple and intuitive color-coded alerting criteria; yet the necessary uncertainty measures by which one can gauge the likelihood for the alert to be over- or underestimated are preserved. The essence of the proposed impact scale and alerting is that actionable loss information is now available in the immediate aftermath of significant earthquakes worldwide on the basis of quantifiable loss estimates. Utilizing EIS, PAGER's rapid loss estimates can adequately recommend alert levels and suggest appropriate response protocols, despite the uncertainties; demanding or awaiting observations or loss estimates with a high level of accuracy may increase the losses. ?? 2011 American Society of Civil Engineers.

  16. Earthquake number forecasts testing

    NASA Astrophysics Data System (ADS)

    Kagan, Yan Y.

    2017-10-01

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

  17. Unraveling earthquake stresses: Insights from dynamically triggered and induced earthquakes

    NASA Astrophysics Data System (ADS)

    Velasco, A. A.; Alfaro-Diaz, R. A.

    2017-12-01

    Induced seismicity, earthquakes caused by anthropogenic activity, has more than doubled in the last several years resulting from practices related to oil and gas production. Furthermore, large earthquakes have been shown to promote the triggering of other events within two fault lengths (static triggering), due to static stresses caused by physical movement along the fault, and also remotely from the passage of seismic waves (dynamic triggering). Thus, in order to understand the mechanisms for earthquake failure, we investigate regions where natural, induced, and dynamically triggered events occur, and specifically target Oklahoma. We first analyze data from EarthScope's USArray Transportable Array (TA) and local seismic networks implementing an optimized (STA/LTA) detector in order to develop local detection and earthquake catalogs. After we identify triggered events through statistical analysis, and perform a stress analysis to gain insight on the stress-states leading to triggered earthquake failure. We use our observations to determine the role of different transient stresses in contributing to natural and induced seismicity by comparing these stresses to regional stress orientation. We also delineate critically stressed regions of triggered seismicity that may indicate areas susceptible to earthquake hazards associated with sustained fluid injection in provinces of induced seismicity. Anthropogenic injection and extraction activity can alter the stress state and fluid flow within production basins. By analyzing the stress release of these ancient faults caused by dynamic stresses, we may be able to determine if fluids are solely responsible for increased seismic activity in induced regions.

  18. The long range transport of birch (Betula) pollen from Poland and Germany causes significant pre-season concentrations in Denmark

    NASA Astrophysics Data System (ADS)

    Ambelas Skjoth, C.; Sommer, J.; Stach, A.; Smith, M.; Brandt, J.; Christensen, J. H.; Frohn, L. M.; Geels, C.; Hansen, K. M.; Hedegaard, G. B.

    2009-04-01

    In Denmark, where birch pollen is considered to be among the most important allergenic pollen, about one million people suffer from seasonal allergic rhinitis. In Denmark, the official reported pollen forecast is based on the daily weather forecast, the pollen calendar and local 24-h measurements. Birch pollen has the potential for long-range transport but the present Danish pollen forecast does not account for birch pollen being transported into the country from distant sources.. Long-range transport episodes are intermittent and often out of the main pollen season, where individuals in general will be medically unprotected. Here we use an integrated approach to investigate whether or not Denmark receives significant quantities of birch pollen from Poland and Germany before local trees start to flower. In 2006 we used a combination of phenological observations and pollen measurements in Poland (Poznań) and Denmark (Copenhagen). Seasonal and diurnal variations in birch pollen measurement from Copenhagen (2000-2006) were examined with the aim of identifying pre-seasonal episodes originating from long-range transport. The 2.5% accumulation method was used for identifying start of season. If daily pollen counts exceeded 30 grains/m3 either before the local flowering season began or on the actual start day, the episode was chosen for investigation with back trajectory analysis. A birch forest inventory for Northern Europe was produced and implemented in DEHM-Pollen along with a simple unified pollen release model SUPREME to investigate the 2006 campaign in detail. In 2006, full flowering took place in Poznan between 20th and 28th of April and daily concentrations varied between 739 and 2169 grains/m3. In Copenhagen phenological observations showed that local flowering was initiated the 2nd of May. In Copenhagen several episodes with pollen concentrations at 108, 244 and 41 grains/m3 were recorded the 23rd, 26th and 27th of April, respectively. Back-trajectory analysis

  19. Earthquake hazards: a national threat

    USGS Publications Warehouse

    ,

    2006-01-01

    Earthquakes are one of the most costly natural hazards faced by the Nation, posing a significant risk to 75 million Americans in 39 States. The risks that earthquakes pose to society, including death, injury, and economic loss, can be greatly reduced by (1) better planning, construction, and mitigation practices before earthquakes happen, and (2) providing critical and timely information to improve response after they occur. As part of the multi-agency National Earthquake Hazards Reduction Program, the U.S. Geological Survey (USGS) has the lead Federal responsibility to provide notification of earthquakes in order to enhance public safety and to reduce losses through effective forecasts based on the best possible scientific information.

  20. Gravity drives Great Earthquakes

    NASA Astrophysics Data System (ADS)

    Lister, Gordon; Forster, Marnie

    2010-05-01

    The most violent of Great Earthquakes are driven by ruptures on giant megathrusts adjacent to actively forming mountain belts. Current theory suggests that the seismic rupture harvests (and thus releases) elastic energy that has been previously stored in locked segments of the megathrust. The general belief, however, is that this energy was accumulated as the result of relative motion of the adjacent stiff elastic tectonic plates. This mechanism fails to explain many first order aspects of large earthquakes, however. The energy source for strain accumulation must also include gravitational collapse of orogenic crust and/or in the foundering (or roll-back) of an adjacent subducting lithospheric slab. Therefore we have conducted an analysis of the geometry of aftershocks, and report that this allows distinction of two types of failure on giant megathrusts. Mode I failure involves horizontal shortening, and is consistent with the classic view that megathrusts fail in compression, with motion analogous to that expected if accretion takes place against a rigid (or elastic) backstop. Mode II failure involves horizontal extension, and requires the over-riding plate to stretch during an earthquake. This process is likely to continue during the subsequent period of afterslip, and therefore will again be evident in aftershock patterns. Mode I behaviour may well have applied to the southern segment of the Sumatran megathrust, from whence emanated the rupture that drove the 2004 Great Earthquake. Mode II behaviour appears to apply to the northern segment of the same rupture, however. The geometry of aftershocks beneath the Andaman Sea suggest that the crust above the initial rupture failed in an extensional mode. The edge of the Indian plate is foundering, with slab-hinge roll-back in a direction orthogonal to its motion vector. The only possible cause for this extension therefore is westward roll-back of the subducting Indian plate, and the consequent gravity-driven movement

  1. Retrospective Cohort Analysis of Chest Injury Characteristics and Concurrent Injuries in Patients Admitted to Hospital in the Wenchuan and Lushan Earthquakes in Sichuan, China

    PubMed Central

    Yuan, Yong; Zhao, Yong-Fan

    2014-01-01

    Background The aim of this study was to compare retrospectively the characteristics of chest injuries and frequencies of other, concurrent injuries in patients after earthquakes of different seismic intensity. Methods We compared the cause, type, and body location of chest injuries as well as the frequencies of other, concurrent injuries in patients admitted to our hospital after the Wenchuan and Lushan earthquakes in Sichuan, China. We explored possible relationships between seismic intensity and the causes and types of injuries, and we assessed the ability of the Injury Severity Score, New Injury Severity Score, and Chest Injury Index to predict respiratory failure in chest injury patients. Results The incidence of chest injuries was 9.9% in the stronger Wenchuan earthquake and 22.2% in the less intensive Lushan earthquake. The most frequent cause of chest injuries in both earthquakes was being accidentally struck. Injuries due to falls were less prevalent in the stronger Wenchuan earthquake, while injuries due to burial were more prevalent. The distribution of types of chest injury did not vary significantly between the two earthquakes, with rib fractures and pulmonary contusions the most frequent types. Spinal and head injuries concurrent with chest injuries were more prevalent in the less violent Lushan earthquake. All three trauma scoring systems showed poor ability to predict respiratory failure in patients with earthquake-related chest injuries. Conclusions Previous studies may have underestimated the incidence of chest injury in violent earthquakes. The distributions of types of chest injury did not differ between these two earthquakes of different seismic intensity. Earthquake severity and interval between rescue and treatment may influence the prevalence and types of injuries that co-occur with the chest injury. Trauma evaluation scores on their own are inadequate predictors of respiratory failure in patients with earthquake-related chest injuries. PMID

  2. Retrospective cohort analysis of chest injury characteristics and concurrent injuries in patients admitted to hospital in the Wenchuan and Lushan earthquakes in Sichuan, China.

    PubMed

    Zheng, Xi; Hu, Yang; Yuan, Yong; Zhao, Yong-Fan

    2014-01-01

    The aim of this study was to compare retrospectively the characteristics of chest injuries and frequencies of other, concurrent injuries in patients after earthquakes of different seismic intensity. We compared the cause, type, and body location of chest injuries as well as the frequencies of other, concurrent injuries in patients admitted to our hospital after the Wenchuan and Lushan earthquakes in Sichuan, China. We explored possible relationships between seismic intensity and the causes and types of injuries, and we assessed the ability of the Injury Severity Score, New Injury Severity Score, and Chest Injury Index to predict respiratory failure in chest injury patients. The incidence of chest injuries was 9.9% in the stronger Wenchuan earthquake and 22.2% in the less intensive Lushan earthquake. The most frequent cause of chest injuries in both earthquakes was being accidentally struck. Injuries due to falls were less prevalent in the stronger Wenchuan earthquake, while injuries due to burial were more prevalent. The distribution of types of chest injury did not vary significantly between the two earthquakes, with rib fractures and pulmonary contusions the most frequent types. Spinal and head injuries concurrent with chest injuries were more prevalent in the less violent Lushan earthquake. All three trauma scoring systems showed poor ability to predict respiratory failure in patients with earthquake-related chest injuries. Previous studies may have underestimated the incidence of chest injury in violent earthquakes. The distributions of types of chest injury did not differ between these two earthquakes of different seismic intensity. Earthquake severity and interval between rescue and treatment may influence the prevalence and types of injuries that co-occur with the chest injury. Trauma evaluation scores on their own are inadequate predictors of respiratory failure in patients with earthquake-related chest injuries.

  3. Understanding Earthquakes

    ERIC Educational Resources Information Center

    Davis, Amanda; Gray, Ron

    2018-01-01

    December 26, 2004 was one of the deadliest days in modern history, when a 9.3 magnitude earthquake--the third largest ever recorded--struck off the coast of Sumatra in Indonesia (National Centers for Environmental Information 2014). The massive quake lasted at least 10 minutes and devastated the Indian Ocean. The quake displaced an estimated…

  4. Earthquake Testing

    NASA Technical Reports Server (NTRS)

    1979-01-01

    During NASA's Apollo program, it was necessary to subject the mammoth Saturn V launch vehicle to extremely forceful vibrations to assure the moonbooster's structural integrity in flight. Marshall Space Flight Center assigned vibration testing to a contractor, the Scientific Services and Systems Group of Wyle Laboratories, Norco, California. Wyle-3S, as the group is known, built a large facility at Huntsville, Alabama, and equipped it with an enormously forceful shock and vibration system to simulate the liftoff stresses the Saturn V would encounter. Saturn V is no longer in service, but Wyle-3S has found spinoff utility for its vibration facility. It is now being used to simulate earthquake effects on various kinds of equipment, principally equipment intended for use in nuclear power generation. Government regulations require that such equipment demonstrate its ability to survive earthquake conditions. In upper left photo, Wyle3S is preparing to conduct an earthquake test on a 25ton diesel generator built by Atlas Polar Company, Ltd., Toronto, Canada, for emergency use in a Canadian nuclear power plant. Being readied for test in the lower left photo is a large circuit breaker to be used by Duke Power Company, Charlotte, North Carolina. Electro-hydraulic and electro-dynamic shakers in and around the pit simulate earthquake forces.

  5. Global earthquake fatalities and population

    USGS Publications Warehouse

    Holzer, Thomas L.; Savage, James C.

    2013-01-01

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

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

    PubMed

    Stein, Seth; Liu, Mian

    2009-11-05

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

  7. Earthquake rupture below the brittle-ductile transition in continental lithospheric mantle

    PubMed Central

    Prieto, Germán A.; Froment, Bérénice; Yu, Chunquan; Poli, Piero; Abercrombie, Rachel

    2017-01-01

    Earthquakes deep in the continental lithosphere are rare and hard to interpret in our current understanding of temperature control on brittle failure. The recent lithospheric mantle earthquake with a moment magnitude of 4.8 at a depth of ~75 km in the Wyoming Craton was exceptionally well recorded and thus enabled us to probe the cause of these unusual earthquakes. On the basis of complete earthquake energy balance estimates using broadband waveforms and temperature estimates using surface heat flow and shear wave velocities, we argue that this earthquake occurred in response to ductile deformation at temperatures above 750°C. The high stress drop, low rupture velocity, and low radiation efficiency are all consistent with a dissipative mechanism. Our results imply that earthquake nucleation in the lithospheric mantle is not exclusively limited to the brittle regime; weakening mechanisms in the ductile regime can allow earthquakes to initiate and propagate. This finding has significant implications for understanding deep earthquake rupture mechanics and rheology of the continental lithosphere. PMID:28345055

  8. Earthquake rupture below the brittle-ductile transition in continental lithospheric mantle.

    PubMed

    Prieto, Germán A; Froment, Bérénice; Yu, Chunquan; Poli, Piero; Abercrombie, Rachel

    2017-03-01

    Earthquakes deep in the continental lithosphere are rare and hard to interpret in our current understanding of temperature control on brittle failure. The recent lithospheric mantle earthquake with a moment magnitude of 4.8 at a depth of ~75 km in the Wyoming Craton was exceptionally well recorded and thus enabled us to probe the cause of these unusual earthquakes. On the basis of complete earthquake energy balance estimates using broadband waveforms and temperature estimates using surface heat flow and shear wave velocities, we argue that this earthquake occurred in response to ductile deformation at temperatures above 750°C. The high stress drop, low rupture velocity, and low radiation efficiency are all consistent with a dissipative mechanism. Our results imply that earthquake nucleation in the lithospheric mantle is not exclusively limited to the brittle regime; weakening mechanisms in the ductile regime can allow earthquakes to initiate and propagate. This finding has significant implications for understanding deep earthquake rupture mechanics and rheology of the continental lithosphere.

  9. 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).

  10. 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.

  11. The Loma Prieta, California, Earthquake of October 17, 1989: Earthquake Occurrence

    USGS Publications Warehouse

    Coordinated by Bakun, William H.; Prescott, William H.

    1993-01-01

    Professional Paper 1550 seeks to understand the M6.9 Loma Prieta earthquake itself. It examines how the fault that generated the earthquake ruptured, searches for and evaluates precursors that may have indicated an earthquake was coming, reviews forecasts of the earthquake, and describes the geology of the earthquake area and the crustal forces that affect this geology. Some significant findings were: * Slip during the earthquake occurred on 35 km of fault at depths ranging from 7 to 20 km. Maximum slip was approximately 2.3 m. The earthquake may not have released all of the strain stored in rocks next to the fault and indicates a potential for another damaging earthquake in the Santa Cruz Mountains in the near future may still exist. * The earthquake involved a large amount of uplift on a dipping fault plane. Pre-earthquake conventional wisdom was that large earthquakes in the Bay area occurred as horizontal displacements on predominantly vertical faults. * The fault segment that ruptured approximately coincided with a fault segment identified in 1988 as having a 30% probability of generating a M7 earthquake in the next 30 years. This was one of more than 20 relevant earthquake forecasts made in the 83 years before the earthquake. * Calculations show that the Loma Prieta earthquake changed stresses on nearby faults in the Bay area. In particular, the earthquake reduced stresses on the Hayward Fault which decreased the frequency of small earthquakes on it. * Geological and geophysical mapping indicate that, although the San Andreas Fault can be mapped as a through going fault in the epicentral region, the southwest dipping Loma Prieta rupture surface is a separate fault strand and one of several along this part of the San Andreas that may be capable of generating earthquakes.

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

    NASA Astrophysics Data System (ADS)

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

    2012-12-01

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

  13. The SCEC/USGS dynamic earthquake rupture code verification exercise

    USGS Publications Warehouse

    Harris, R.A.; Barall, M.; Archuleta, R.; Dunham, E.; Aagaard, Brad T.; Ampuero, J.-P.; Bhat, H.; Cruz-Atienza, Victor M.; Dalguer, L.; Dawson, P.; Day, S.; Duan, B.; Ely, G.; Kaneko, Y.; Kase, Y.; Lapusta, N.; Liu, Yajing; Ma, S.; Oglesby, D.; Olsen, K.; Pitarka, A.; Song, S.; Templeton, E.

    2009-01-01

    Numerical simulations of earthquake rupture dynamics are now common, yet it has been difficult to test the validity of these simulations because there have been few field observations and no analytic solutions with which to compare the results. This paper describes the Southern California Earthquake Center/U.S. Geological Survey (SCEC/USGS) Dynamic Earthquake Rupture Code Verification Exercise, where codes that simulate spontaneous rupture dynamics in three dimensions are evaluated and the results produced by these codes are compared using Web-based tools. This is the first time that a broad and rigorous examination of numerous spontaneous rupture codes has been performed—a significant advance in this science. The automated process developed to attain this achievement provides for a future where testing of codes is easily accomplished.Scientists who use computer simulations to understand earthquakes utilize a range of techniques. Most of these assume that earthquakes are caused by slip at depth on faults in the Earth, but hereafter the strategies vary. Among the methods used in earthquake mechanics studies are kinematic approaches and dynamic approaches.The kinematic approach uses a computer code that prescribes the spatial and temporal evolution of slip on the causative fault (or faults). These types of simulations are very helpful, especially since they can be used in seismic data inversions to relate the ground motions recorded in the field to slip on the fault(s) at depth. However, these kinematic solutions generally provide no insight into the physics driving the fault slip or information about why the involved fault(s) slipped that much (or that little). In other words, these kinematic solutions may lack information about the physical dynamics of earthquake rupture that will be most helpful in forecasting future events.To help address this issue, some researchers use computer codes to numerically simulate earthquakes and construct dynamic, spontaneous

  14. 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.

  15. Earthquake Catalogue of the Caucasus

    NASA Astrophysics Data System (ADS)

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

    2016-12-01

    The Caucasus has a documented historical catalog stretching back to the beginning of the Christian era. Most of the largest historical earthquakes prior to the 19th century are assumed to have occurred on active faults of the Greater Caucasus. Important earthquakes include the Samtskhe earthquake of 1283 (Ms˜7.0, Io=9); Lechkhumi-Svaneti earthquake of 1350 (Ms˜7.0, Io=9); and the Alaverdi earthquake of 1742 (Ms˜6.8, Io=9). Two significant historical earthquakes that may have occurred within the Javakheti plateau in the Lesser Caucasus are the Tmogvi earthquake of 1088 (Ms˜6.5, Io=9) and the Akhalkalaki earthquake of 1899 (Ms˜6.3, Io =8-9). Large earthquakes that occurred in the Caucasus within the period of instrumental observation are: Gori 1920; Tabatskuri 1940; Chkhalta 1963; Racha earthquake of 1991 (Ms=7.0), is the largest event ever recorded in the region; Barisakho earthquake of 1992 (M=6.5); Spitak earthquake of 1988 (Ms=6.9, 100 km south of Tbilisi), which killed over 50,000 people in Armenia. Recently, permanent broadband stations have been deployed across the region as part of the various national networks (Georgia (˜25 stations), Azerbaijan (˜35 stations), Armenia (˜14 stations)). The data from the last 10 years of observation provides an opportunity to perform modern, fundamental scientific investigations. In order to improve seismic data quality a catalog of all instrumentally recorded earthquakes has been compiled by the IES (Institute of Earth Sciences/NSMC, Ilia State University) in the framework of regional joint project (Armenia, Azerbaijan, Georgia, Turkey, USA) "Probabilistic Seismic Hazard Assessment (PSHA) in the Caucasus. The catalogue consists of more then 80,000 events. First arrivals of each earthquake of Mw>=4.0 have been carefully examined. To reduce calculation errors, we corrected arrivals from the seismic records. We improved locations of the events and recalculate Moment magnitudes in order to obtain unified magnitude

  16. Housing Damage Following Earthquake

    NASA Technical Reports Server (NTRS)

    1989-01-01

    An automobile lies crushed under the third story of this apartment building in the Marina District after the Oct. 17, 1989, Loma Prieta earthquake. The ground levels are no longer visible because of structural failure and sinking due to liquefaction. Sand and soil grains have faces that can cause friction as they roll and slide against each other, or even cause sticking and form small voids between grains. This complex behavior can cause soil to behave like a liquid under certain conditions such as earthquakes or when powders are handled in industrial processes. Mechanics of Granular Materials (MGM) experiments aboard the Space Shuttle use the microgravity of space to simulate this behavior under conditons that carnot be achieved in laboratory tests on Earth. MGM is shedding light on the behavior of fine-grain materials under low effective stresses. Applications include earthquake engineering, granular flow technologies (such as powder feed systems for pharmaceuticals and fertilizers), and terrestrial and planetary geology. Nine MGM specimens have flown on two Space Shuttle flights. Another three are scheduled to fly on STS-107. The principal investigator is Stein Sture of the University of Colorado at Boulder. Credit: J.K. Nakata, U.S. Geological Survey.

  17. Sand Volcano Following Earthquake

    NASA Technical Reports Server (NTRS)

    1989-01-01

    Sand boil or sand volcano measuring 2 m (6.6 ft.) in length erupted in median of Interstate Highway 80 west of the Bay Bridge toll plaza when ground shaking transformed loose water-saturated deposit of subsurface sand into a sand-water slurry (liquefaction) in the October 17, 1989, Loma Prieta earthquake. Vented sand contains marine-shell fragments. Sand and soil grains have faces that can cause friction as they roll and slide against each other, or even cause sticking and form small voids between grains. This complex behavior can cause soil to behave like a liquid under certain conditions such as earthquakes or when powders are handled in industrial processes. Mechanics of Granular Materials (MGM) experiments aboard the Space Shuttle use the microgravity of space to simulate this behavior under conditions that carnot be achieved in laboratory tests on Earth. MGM is shedding light on the behavior of fine-grain materials under low effective stresses. Applications include earthquake engineering, granular flow technologies (such as powder feed systems for pharmaceuticals and fertilizers), and terrestrial and planetary geology. Nine MGM specimens have flown on two Space Shuttle flights. Another three are scheduled to fly on STS-107. The principal investigator is Stein Sture of the University of Colorado at Boulder. (Credit: J.C. Tinsley, U.S. Geological Survey)

  18. 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. 

  19. The next new Madrid earthquake

    SciTech Connect

    Atkinson, W.

    1988-01-01

    Scientists who specialize in the study of Mississippi Valley earthquakes say that the region is overdue for a powerful tremor that will cause major damage and undoubtedly some casualties. The inevitability of a future quake and the lack of preparation by both individuals and communities provided the impetus for this book. It brings together applicable information from many disciplines: history, geology and seismology, engineering, zoology, politics and community planning, economics, environmental science, sociology, and psychology and mental health to provide a perspective of the myriad impacts of a major earthquake on the Mississippi Valley. The author addresses such basic questionsmore » as What, actually, are earthquakes How do they occur Can they be predicted, perhaps even prevented He also addresses those steps that individuals can take to improve their chances for survival both during and after an earthquake.« less

  20. YaAn earthquake increases blood pressure among hospitalized patients.

    PubMed

    Li, Chuanwei; Luo, Xiaoli; Zhang, Wen; Zhou, Liang; Wang, Hongyong; Zeng, Chunyu

    YaAn, a city in Sichuan province, China, was struck by a major earthquake measuring 7.0 on the Richter scale on April 20, 2013. This study sought to investigate the impact of YaAn earthquake on the blood pressure (BP) among hospitalized patients in the department of cardiology. We enrolled 52 hospitalized patients who were admitted to our hospital at least three days before the day of earthquake in 2013 (disaster group) as compared with 52 patients during April 20, 2014 (nondisaster group). BP was measured three times per day and the prescription of antihypertensive medicine was recorded. The earthquake induced a 3.3 mm Hg significant increase in the mean postdisaster systolic blood pressure (SBP) in the disaster group as compared with the nondisaster group. SBP at admission was positively associated with the elevated SBP in the logistic regression model (odds ratio (OR) = 1.09, 95% confidence interval (CI):1.016-1.168, p = 0.015), but not other potential influencing factors, including antihypertensive medicine, sex, age, and body weight, excluding β-blockers. Patients with β-blockers prescription at the time of earthquake showed a blunt response to earthquake-induced SBP elevation than those who were taking other antihypertensive drugs (OR = 0.128, 95% CI: 0.019-0.876, p = 0.036). The YaAn earthquake induced significant increase in SBP even at a distance from the epicenter among hospitalized patients. The findings demonstrate that pure psychological components seem to be a cause of the pressor response and β-blockers might be better in controlling disaster-induced hypertension.

  1. 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

  2. The mechanism of earthquake

    NASA Astrophysics Data System (ADS)

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

    2018-03-01

    earthquakes and deep-focus earthquakes are the energy release caused by the slip or flow of rocks following a jamming-unjamming transition. (4) The energetics and impending precursors of earthquake: The energy of earthquake is the kinetic energy released from the jamming-unjamming transition. Calculation shows that the kinetic energy of seismic rock sliding is comparable with the total work demanded for rocks’ shear failure and overcoming of frictional resistance. There will be no heat flow paradox. Meanwhile, some valuable seismic precursors are likely to be identified by observing the accumulation of additional tectonic forces, local geological changes, as well as the effect of rock state changes, etc.

  3. Connecting slow earthquakes to huge earthquakes.

    PubMed

    Obara, Kazushige; Kato, Aitaro

    2016-07-15

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

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

    NASA Astrophysics Data System (ADS)

    Muhammad, Ario; Goda, Katsuichiro; Alexander, Nicholas A.; Kongko, Widjo; Muhari, Abdul

    2017-12-01

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

  5. Near real-time aftershock hazard maps for earthquakes

    NASA Astrophysics Data System (ADS)

    McCloskey, J.; Nalbant, S. S.

    2009-04-01

    Stress interaction modelling is routinely used to explain the spatial relationships between earthquakes and their aftershocks. On 28 October 2008 a M6.4 earthquake occurred near the Pakistan-Afghanistan border killing several hundred and causing widespread devastation. A second M6.4 event occurred 12 hours later 20km to the south east. By making some well supported assumptions concerning the source event and the geometry of any likely triggered event it was possible to map those areas most likely to experience further activity. Using Google earth, it would further have been possible to identify particular settlements in the source area which were particularly at risk and to publish their locations globally within about 3 hours of the first earthquake. Such actions could have significantly focused the initial emergency response management. We argue for routine prospective testing of such forecasts and dialogue between social and physical scientists and emergency response professionals around the practical application of these techniques.

  6. Defeating Earthquakes

    NASA Astrophysics Data System (ADS)

    Stein, R. S.

    2012-12-01

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

  7. Centimeter-scale surface deformation caused by the 2011 Mineral, Virginia, earthquake sequence at the Carter farm site—Subsidiary structures with a quaternary history

    USGS Publications Warehouse

    Harrison, Richard W.; Schindler, J. Stephen; Pavich, Milan J.; Horton, J. Wright; Carter, Mark W.

    2016-08-25

    Centimeter-scale ground-surface deformation was produced by the August 23, 2011, magnitude (M) 5.8 earthquake that occurred in Mineral, Virginia. Ground-surface deformation also resulted from the earthquake aftershock sequence. This deformation occurred along a linear northeast-trend near Pendleton, Virginia. It is approximately 10 kilometers (km) northeast of the M5.8 epicenter and near the northeastern periphery of the epicentral area as defined by aftershocks. The ground-surface deformation extends over a distance of approximately 1.4 km and consists of parallel, small-scale (a few centimeters (cm) in amplitude) linear ridges and swales. Individual ridge and swale features are discontinuous and vary in length across a zone that ranges from about 20 meters (m) to less than 5 m in width. At one location, three fence posts and adjoining rails were vertically misaligned. Approximately 5 cm of uplift on one post provides a maximum estimate of vertical change from pre-earthquake conditions along the ridge and swale features. There was no change in the alignment of fence posts, indicating that deformation was entirely vertical. A broad monoclinal flexure with approximately 1 m of relief was identified by transit survey across surface deformation at the Carter farm site. There, surface deformation overlies the Carter farm fault, which is a zone of brittle faulting and fracturing along quartz veins, striking N40°E and dipping approximately 75°SE. Brecciation and shearing along this fault is interpreted as Quaternary in age because it disrupts the modern B-soil horizon. However, deformation is confined to saprolitized schist of the Ordovician Quantico Formation and the lowermost portion of overlying residuum, and is absent in the uppermost residuum and colluvial layer at the ground surface. Because there is a lack of surface shearing and very low relief, landslide processes were not a causative mechanism for the surface deformation. Two possible tectonic models and one

  8. Responses of a tall building in Los Angeles, California as inferred from local and distant earthquakes

    USGS Publications Warehouse

    Çelebi, Mehmet; Hasan Ulusoy,; Nori Nakata,

    2016-01-01

    Increasing inventory of tall buildings in the United States and elsewhere may be subjected to motions generated by near and far seismic sources that cause long-period effects. Multiple sets of records that exhibited such effects were retrieved from tall buildings in Tokyo and Osaka ~ 350 km and 770 km from the epicenter of the 2011 Tohoku earthquake. In California, very few tall buildings have been instrumented. An instrumented 52-story building in downtown Los Angeles recorded seven local and distant earthquakes. Spectral and system identification methods exhibit significant low frequencies of interest (~0.17 Hz, 0.56 Hz and 1.05 Hz). These frequencies compare well with those computed by transfer functions; however, small variations are observed between the significant low frequencies for each of the seven earthquakes. The torsional and translational frequencies are very close and are coupled. Beating effect is observed in at least two of the seven earthquake data.

  9. [Analysis of the changes in the causes of blindness and significant vision loss among children and young adults born between 1974 and 2004].

    PubMed

    Seroczyńska, Małgorzata; Grałek, Mirosława; Kanigowska, Krystyna

    2007-01-01

    Visual impairment develops serious medical, psychological, social and economical problems. Thus, of most importance is improvement in prophylaxis, early diagnosis and treatment. THE AIM of this paper is to define the reasons of blindness and significant loss of vision in children and youths in Poland, and changes in them among children and youths under the age of 24, born between 1974-2004, with classification by age. Included in the study were the records of 2,518 children and youths under the age of 24, associates of the Polski Zwiazek Niewidomych (PZN, Polish Association of the Blind); these were analyzed for the prevalence of each cause of vision loss. There were two groups. The first group were files of 1,504 students and pupils in the institutions for blind and visually impaired children, and the archives of PZN, describing the members who joined it between year 1974 and 1998. The second, comparative group, was based on files of 1,014 children and students, who joined PZN between year 1999 and 2004. Each group was also analysed within different age groups. The most important causes of visual impairment are: optic nerve atrophy, retinopathy of prematurity (ROP), high myopia, congenital cataract and retinal degradations. Changes in them between 1998-2004 introduce a percentage growth of optic nerve atrophy from 21.66% to 25.41% and decrement in vision degrading stages of ROP from 14.14% to 10.71%, in development disorders from 8.09% to 7.10%. There is an alarming growth in congenital toxoplasmosis percentage, from 1.06% to 2.39%, and of congenital cataract, from 3.02% to 4.47%. High myopia among the visually impaired remains at the same level. There is a big growth in the percentage of heavy (bilateral) injuries, which cause significant vision loss. Less often, the cause of serious vision damage are uveitis, secondary glaucoma and toxocariasis. The study conducted between 1998-2004 revealed changes in the causes of blindness and significantly vision loss in

  10. Association between earthquake events and cholera outbreaks: a cross-country 15-year longitudinal analysis.

    PubMed

    Sumner, Steven A; Turner, Elizabeth L; Thielman, Nathan M

    2013-12-01

    Large earthquakes can cause population displacement, critical sanitation infrastructure damage, and increased threats to water resources, potentially predisposing populations to waterborne disease epidemics such as cholera. Problem The risk of cholera outbreaks after earthquake disasters remains uncertain. A cross-country analysis of World Health Organization (WHO) cholera data that would contribute to this discussion has yet to be published. A cross-country longitudinal analysis was conducted among 63 low- and middle-income countries from 1995-2009. The association between earthquake disasters of various effect sizes and a relative spike in cholera rates for a given country was assessed utilizing fixed-effects logistic regression and adjusting for gross domestic product per capita, water and sanitation level, flooding events, percent urbanization, and under-five child mortality. Also, the association between large earthquakes and cholera rate increases of various degrees was assessed. Forty-eight of the 63 countries had at least one year with reported cholera infections during the 15-year study period. Thirty-six of these 48 countries had at least one earthquake disaster. In adjusted analyses, country-years with ≥10,000 persons affected by an earthquake had 2.26 times increased odds (95 CI, 0.89-5.72, P = .08) of having a greater than average cholera rate that year compared to country-years having <10,000 individuals affected by an earthquake. The association between large earthquake disasters and cholera infections appeared to weaken as higher levels of cholera rate increases were tested. A trend of increased risk of greater than average cholera rates when more people were affected by an earthquake in a country-year was noted. However these findings did not reach statistical significance at traditional levels and may be due to chance. Frequent large-scale cholera outbreaks after earthquake disasters appeared to be relatively uncommon.

  11. Twitter earthquake detection: Earthquake monitoring in a social world

    USGS Publications Warehouse

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

    2011-01-01

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

  12. Earthquake Hazard and the Environmental Seismic Intensity (ESI) Scale

    NASA Astrophysics Data System (ADS)

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

    2016-05-01

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

  13. Earthquakes and depleted gas reservoirs: which comes first?

    NASA Astrophysics Data System (ADS)

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

    2015-10-01

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

  14. Insignificant solar-terrestrial triggering of earthquakes

    USGS Publications Warehouse

    Love, Jeffrey J.; Thomas, Jeremy N.

    2013-01-01

    We examine the claim that solar-terrestrial interaction, as measured by sunspots, solar wind velocity, and geomagnetic activity, might play a role in triggering earthquakes. We count the number of earthquakes having magnitudes that exceed chosen thresholds in calendar years, months, and days, and we order these counts by the corresponding rank of annual, monthly, and daily averages of the solar-terrestrial variables. We measure the statistical significance of the difference between the earthquake-number distributions below and above the median of the solar-terrestrial averages by χ2 and Student's t tests. Across a range of earthquake magnitude thresholds, we find no consistent and statistically significant distributional differences. We also introduce time lags between the solar-terrestrial variables and the number of earthquakes, but again no statistically significant distributional difference is found. We cannot reject the null hypothesis of no solar-terrestrial triggering of earthquakes.

  15. Earthquakes and depleted gas reservoirs: which comes first?

    NASA Astrophysics Data System (ADS)

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

    2014-12-01

    While scientists are paying increasing attention to the seismicity potentially induced by hydrocarbon exploitation, little is known about the reverse problem, i.e. the impact of active faulting and earthquakes on hydrocarbon reservoirs. The recent 2012 earthquakes in Emilia, Italy, raised concerns among the public for being possibly human-induced, but also shed light on the possible use of gas wells as a marker of the seismogenic potential of an active fold-and-thrust belt. Based on the analysis of over 400 borehole datasets from wells drilled along the Ferrara-Romagna Arc, a large oil and gas reserve in the southeastern Po Plain, we found that the 2012 earthquakes occurred within a cluster of sterile wells surrounded by productive ones. Since the geology of the productive and sterile areas is quite similar, we suggest that past earthquakes caused the loss of all natural gas from the potential reservoirs lying above their causative faults. Our findings have two important practical implications: (1) they may allow major seismogenic zones to be identified in areas of sparse seismicity, and (2) suggest that gas should be stored in exploited reservoirs rather than in sterile hydrocarbon traps or aquifers as this is likely to reduce the hazard of triggering significant earthquakes.

  16. Landslides Triggered by the 2015 Gorkha, Nepal Earthquake

    NASA Astrophysics Data System (ADS)

    Xu, C.

    2018-04-01

    The 25 April 2015 Gorkha Mw 7.8 earthquake in central Nepal caused a large number of casualties and serious property losses, and also induced numerous landslides. Based on visual interpretation of high-resolution optical satellite images pre- and post-earthquake and field reconnaissance, we delineated 47,200 coseismic landslides with a total distribution extent more than 35,000 km2, which occupy a total area about 110 km2. On the basis of a scale relationship between landslide area (A) and volume (V), V = 1.3147 × A1.2085, the total volume of the coseismic landslides is estimated to be about 9.64 × 108 m3. Calculation yields that the landslide number density, area density, and volume density are 1.32 km-2, 0.31 %, and 0.027 m, respectively. The spatial distribution of these landslides is consistent with that of the mainshock and aftershocks and the inferred causative fault, indicating the effect of the earthquake energy release on the pattern on coseismic landslides. This study provides a new, more detailed and objective inventory of the landslides triggered by the Gorkha earthquake, which would be significant for further study of genesis of coseismic landslides, hazard assessment and the long-term impact of the slope failure on the geological environment in the earthquake-scarred region.

  17. Real Time Earthquake Information System in Japan

    NASA Astrophysics Data System (ADS)

    Doi, K.; Kato, T.

    2003-12-01

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

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

    NASA Astrophysics Data System (ADS)

    Serata, S.

    2006-12-01

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

  19. Estimated cause of extreme acceleration records at the KiK-net IWTH25 station during the 2008 Iwate-Miyagi Nairiku earthquake, Japan

    NASA Astrophysics Data System (ADS)

    Ohmachi, Tatsuo; Inoue, Shusaku; Mizuno, Ken-Ichi; Yamada, Masato

    During the 2008 Iwate-Miyagi Nairiku earthquake in Japan (MJ =7.2), extremely high accelerations were recorded at the KiK-net IWTH25 (Ichinoseki-nishi) station. The peak acceleration in the vertical component of the surface record was about 4 g where g is acceleration due to gravity, and the upward acceleration in the surface record was much larger than the downward acceleration. Some researchers have suggested that the ground surface was tossed into the air like a body on a trampoline. However, additional features found in the surface record suggest rocking motion accompanied with downward impact of the station with the ground. For example, there are many vertical peaks that can be found to occur at the same time as the horizontal peaks. After obtaining information about the station, in-situ investigations, shake-table experiments, and numerical simulations were conducted to determine the fundamental characteristics of the rocking motion and to reproduce the acceleration time histories of the surface record by using the bore-hole record at a depth of 260 m as the input motion. Prior to the numerical simulation, the wave velocities of subsurface layers were evaluated from Fourier spectra of both records, which showed that the velocities were reduced considerably during the main shock. A 2-D FEM code capable of handling separation and impact between the elements was used for the numerical simulation. Simulation results are shown in Figs. 17 and 18 indicating the impact between the IWTH25 station and the ground at around 4 sec when the acceleration in the vertical direction was about 4 g. Three kinds of acceleration time histories are shown with fairly good agreement between the simulated and observed time histories, suggesting the influence of the station is included in the record. It is also indicated that the vertical acceleration at the free surface without the influence of the IWTH25 station is about 1.6 g.

  20. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2017-12-01

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

  2. Earthquake Potential in Myanmar

    NASA Astrophysics Data System (ADS)

    Aung, Hla Hla

    Myanmar region is generally believed to be an area of high earthquake potential from the point of view of seismic activity which has been low compared to the surrounding regions like Indonesia, China, and Pakistan. Geoscientists and seismologists predicted earthquakes to occur in the area north of the Sumatra-Andaman Islands, i.e. the southwest and west part of Myanmar. Myanmar tectonic setting relative to East and SE Asia is rather peculiar and unique with different plate tectonic models but similar to the setting of western part of North America. Myanmar crustal blocks are caught within two lithospheric plates of India and Indochina experiencing oblique subduction with major dextral strike-slip faulting of the Sagaing fault. Seismic tomography and thermal structure of India plate along the Sunda subduction zone vary from south to north. Strong partitioning in central Andaman basin where crustal fragmentation and northward dispersion of Burma plate by back-arc spreading mechanism has been operating since Neogene. Northward motion of Burma plate relative to SE Asia would dock against the major continent further north and might have caused the accumulation of strain which in turn will be released as earthquakes in the future.

  3. 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

  4. 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.

  5. Man-made Earthquakes & Multifractals in Neutral Fluid Turbulence/Injection

    NASA Astrophysics Data System (ADS)

    Maksoed, Wh-

    Man-made earthquakes coincides with induced seismicity:''typically minor earthquakes & tremors that are caused by human activity that alters the stresses & Strains on the earth crust''[Wikipedia:''induced seismicity'']. For these, RD Andrews wrote:''Based on observed seismicity rate &geographical trends following major oil & gas plays with large amounts of produced water, the rates &trends in seismicity are very unlikely to represent a naturally occurring process''. ``The Prague, Oklahoma, earthquake sequence of 2011, along the Wilzetta faults zone, included the significant foreshock, a main shock of magnetic 5.7, it has been suggested that this sequence represent earthquakes triggered by fluid injection/natural fluid turbulence shows multifractal characteristics , of [405 ]-325-7968 of Dr. G. Randy Keller to UI tuitions of @ Rp. 29, 405, 000.00. Acknowledgements to HE. Mr. H. TUK SETYOHADI, Jl. Sriwijaya Raya 3, South-Jakarta, INDONESIA.

  6. The use of waveform shapes to automatically determine earthquake focal depth

    USGS Publications Warehouse

    Sipkin, S.A.

    2000-01-01

    Earthquake focal depth is an important parameter for rapidly determining probable damage caused by a large earthquake. In addition, it is significant both for discriminating between natural events and explosions and for discriminating between tsunamigenic and nontsunamigenic earthquakes. For the purpose of notifying emergency management and disaster relief organizations as well as issuing tsunami warnings, potential time delays in determining source parameters are particularly detrimental. We present a method for determining earthquake focal depth that is well suited for implementation in an automated system that utilizes the wealth of broadband teleseismic data that is now available in real time from the global seismograph networks. This method uses waveform shapes to determine focal depth and is demonstrated to be valid for events with magnitudes as low as approximately 5.5.

  7. 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.

  8. Urban Earthquakes - Reducing Building Collapse Through Education

    NASA Astrophysics Data System (ADS)

    Bilham, R.

    2004-12-01

    Fatalities from earthquakes rose from 6000k to 9000k/year in the past decade, yet the ratio of numbers of earthquake fatalities to instantaneous population continues to fall. Since 1950 the ratio declined worldwide by a factor of three, but in some countries the ratio has changed little. E.g in Iran, 1 in 3000 people can expect to die in an earthquake, a percentage that has not changed significantly since 1890. Fatalities from earthquakes remain high in those countries that have traditionally suffered from frequent large earthquakes (Turkey, Iran, Japan, and China), suggesting that the exposure time of recently increased urban populations in other countries may be too short to have interacted with earthquakes with long recurrence intervals. This in turn, suggests that disasters of unprecendented size will occur (more than 1 million fatalities) when future large earthquakes occur close to megacities. However, population growth is most rapid in cities of less than 1 million people in the developing nations, where the financial ability to implement earthquake resistant construction methods is limited. In that structural collapse can often be traced to ignorance about the forces at work in an earthquake, the future collapse of buildings presently under construction could be much reduced were contractors, builders and occupants educated in the principles of earthquake resistant assembly. Education of builders who are tempted to cut assembly costs is likely to be more cost effective than material aid.

  9. Foreshock and aftershocks in simple earthquake models.

    PubMed

    Kazemian, J; Tiampo, K F; Klein, W; Dominguez, R

    2015-02-27

    Many models of earthquake faults have been introduced that connect Gutenberg-Richter (GR) scaling to triggering processes. However, natural earthquake fault systems are composed of a variety of different geometries and materials and the associated heterogeneity in physical properties can cause a variety of spatial and temporal behaviors. This raises the question of how the triggering process and the structure interact to produce the observed phenomena. Here we present a simple earthquake fault model based on the Olami-Feder-Christensen and Rundle-Jackson-Brown cellular automata models with long-range interactions that incorporates a fixed percentage of stronger sites, or asperity cells, into the lattice. These asperity cells are significantly stronger than the surrounding lattice sites but eventually rupture when the applied stress reaches their higher threshold stress. The introduction of these spatial heterogeneities results in temporal clustering in the model that mimics that seen in natural fault systems along with GR scaling. In addition, we observe sequences of activity that start with a gradually accelerating number of larger events (foreshocks) prior to a main shock that is followed by a tail of decreasing activity (aftershocks). This work provides further evidence that the spatial and temporal patterns observed in natural seismicity are strongly influenced by the underlying physical properties and are not solely the result of a simple cascade mechanism.

  10. Dancing Earthquake Science Assists Recovery from the Christchurch Earthquakes

    ERIC Educational Resources Information Center

    Egan, Candice J.; Quigley, Mark C.

    2015-01-01

    The 2010-2012 Christchurch (Canterbury) earthquakes in New Zealand caused loss of life and psychological distress in residents throughout the region. In 2011, student dancers of the Hagley Dance Company and dance professionals choreographed the performance "Move: A Seismic Journey" for the Christchurch Body Festival that explored…

  11. Identification of Deep Earthquakes

    DTIC Science & Technology

    2010-09-01

    discriminants that will reliably separate small, crustal earthquakes (magnitudes less than about 4 and depths less than about 40 to 50 km) from small...characteristics on discrimination plots designed to separate nuclear explosions from crustal earthquakes. Thus, reliably flagging these small, deep events is...Further, reliably identifying subcrustal earthquakes will allow us to eliminate deep events (previously misidentified as crustal earthquakes) from

  12. Earthquake Triggering in the September 2017 Mexican Earthquake Sequence

    NASA Astrophysics Data System (ADS)

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

    2017-12-01

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

  13. Geological and historical evidence of irregular recurrent earthquakes in Japan.

    PubMed

    Satake, Kenji

    2015-10-28

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

  14. Revisiting the 1872 Owens Valley, California, Earthquake

    USGS Publications Warehouse

    Hough, S.E.; Hutton, K.

    2008-01-01

    The 26 March 1872 Owens Valley earthquake is among the largest historical earthquakes in California. The felt area and maximum fault displacements have long been regarded as comparable to, if not greater than, those of the great San Andreas fault earthquakes of 1857 and 1906, but mapped surface ruptures of the latter two events were 2-3 times longer than that inferred for the 1872 rupture. The preferred magnitude estimate of the Owens Valley earthquake has thus been 7.4, based largely on the geological evidence. Reinterpreting macroseismic accounts of the Owens Valley earthquake, we infer generally lower intensity values than those estimated in earlier studies. Nonetheless, as recognized in the early twentieth century, the effects of this earthquake were still generally more dramatic at regional distances than the macroseismic effects from the 1906 earthquake, with light damage to masonry buildings at (nearest-fault) distances as large as 400 km. Macroseismic observations thus suggest a magnitude greater than that of the 1906 San Francisco earthquake, which appears to be at odds with geological observations. However, while the mapped rupture length of the Owens Valley earthquake is relatively low, the average slip was high. The surface rupture was also complex and extended over multiple fault segments. It was first mapped in detail over a century after the earthquake occurred, and recent evidence suggests it might have been longer than earlier studies indicated. Our preferred magnitude estimate is Mw 7.8-7.9, values that we show are consistent with the geological observations. The results of our study suggest that either the Owens Valley earthquake was larger than the 1906 San Francisco earthquake or that, by virtue of source properties and/or propagation effects, it produced systematically higher ground motions at regional distances. The latter possibility implies that some large earthquakes in California will generate significantly larger ground motions than San

  15. 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

  16. Earthquake precursors from InSAR geodesy: insights from the L'Aquila (Central Italy) April 6, 2009 earthquake

    NASA Astrophysics Data System (ADS)

    Bignami, C.; Moro, M.; Saroli, M.; Stramondo, S.; Albano, M.; Falcucci, E.; Gori, S.; Doglioni, C.; Polcari, M.; Tallini, M.; Macerola, L.; Novali, F.; Costantini, M.; Malvarosa, F.; Wegmüller, U.

    2017-12-01

    In modern seismology, the identification of earthquake precursors is one of the most important issue to investigate on. Precursor indicators based on the use of updated and most satellite advanced geodetic techniques such as GPS and SAR interferometry, have not been conclusively identified so far. However, the latest progress in terms of new satellite missions and processing algorithms may bring this goal closer. Here we present evidence of ground deformation signals preceding the 2009 L'Aquila earthquake, which have been observed using multi-temporal InSAR techniques. We exploited a wide dataset from RADARSAT2, ENVISAT and COSMO-SkyMed missions to derive mean velocity and ground acceleration maps of the epicentral area, for a time span of approximately 6 years before the earthquake and about one year after the earthquake. The maps of ground accelerations before the mainshock, have allowed the identification of two peculiar displacement patterns, well localized in two Quaternary basins, close to the focal volume of the seismic event (Mw 6.3) that hit the city of L'Aquila on 6 April 2009. In these two regions, a significant subsidence began approximately three years before the earthquake, reaching a value of about 1.5 cm, and persisted until the earthquake. Conversely, in the post-seismic phase, the two basins showed an uplift, with velocities approximately of 5 to 18 mm/yr. The deep knowledge of the geological, hydrogeological and geotechnical setting of the area has provided a plausible explanation of the observed phenomenon. The two Quaternary basins are filled with sediments that host multi-layer aquifers that are hydrologically connected with the neighbouring carbonatic hydrostructures. Before the earthquake, the rocks at depth have dilated and fractures opened. Consequently, fluids have migrated into the dilated volume causing the lowering the groundwater table in the carbonate hydrostructures and in the hydrologically connected multi-layer aquifers within the

  17. 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.

  18. Earthquake and tsunami forecasts: Relation of slow slip events to subsequent earthquake rupture

    PubMed Central

    Dixon, Timothy H.; Jiang, Yan; Malservisi, Rocco; McCaffrey, Robert; Voss, Nicholas; Protti, Marino; Gonzalez, Victor

    2014-01-01

    The 5 September 2012 Mw 7.6 earthquake on the Costa Rica subduction plate boundary followed a 62-y interseismic period. High-precision GPS recorded numerous slow slip events (SSEs) in the decade leading up to the earthquake, both up-dip and down-dip of seismic rupture. Deeper SSEs were larger than shallower ones and, if characteristic of the interseismic period, release most locking down-dip of the earthquake, limiting down-dip rupture and earthquake magnitude. Shallower SSEs were smaller, accounting for some but not all interseismic locking. One SSE occurred several months before the earthquake, but changes in Mohr–Coulomb failure stress were probably too small to trigger the earthquake. Because many SSEs have occurred without subsequent rupture, their individual predictive value is limited, but taken together they released a significant amount of accumulated interseismic strain before the earthquake, effectively defining the area of subsequent seismic rupture (rupture did not occur where slow slip was common). Because earthquake magnitude depends on rupture area, this has important implications for earthquake hazard assessment. Specifically, if this behavior is representative of future earthquake cycles and other subduction zones, it implies that monitoring SSEs, including shallow up-dip events that lie offshore, could lead to accurate forecasts of earthquake magnitude and tsunami potential. PMID:25404327

  19. Earthquake and tsunami forecasts: relation of slow slip events to subsequent earthquake rupture.

    PubMed

    Dixon, Timothy H; Jiang, Yan; Malservisi, Rocco; McCaffrey, Robert; Voss, Nicholas; Protti, Marino; Gonzalez, Victor

    2014-12-02

    The 5 September 2012 M(w) 7.6 earthquake on the Costa Rica subduction plate boundary followed a 62-y interseismic period. High-precision GPS recorded numerous slow slip events (SSEs) in the decade leading up to the earthquake, both up-dip and down-dip of seismic rupture. Deeper SSEs were larger than shallower ones and, if characteristic of the interseismic period, release most locking down-dip of the earthquake, limiting down-dip rupture and earthquake magnitude. Shallower SSEs were smaller, accounting for some but not all interseismic locking. One SSE occurred several months before the earthquake, but changes in Mohr-Coulomb failure stress were probably too small to trigger the earthquake. Because many SSEs have occurred without subsequent rupture, their individual predictive value is limited, but taken together they released a significant amount of accumulated interseismic strain before the earthquake, effectively defining the area of subsequent seismic rupture (rupture did not occur where slow slip was common). Because earthquake magnitude depends on rupture area, this has important implications for earthquake hazard assessment. Specifically, if this behavior is representative of future earthquake cycles and other subduction zones, it implies that monitoring SSEs, including shallow up-dip events that lie offshore, could lead to accurate forecasts of earthquake magnitude and tsunami potential.

  20. 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

  1. Urban Landslides Induced by the 2004 Niigata-Chuetsu Earthquake

    NASA Astrophysics Data System (ADS)

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

    2005-05-01

    Landslides triggered by the Chuetsu earthquake occurred in artificial slopes of some new developments in suburban Nagaoka, the largest city in the affected area. The landslides occurred in hilly terrain of the eastern part of Nagaoka between the alluvial plain and Tertiary folded mountains of Yamakoshi. Although the extent of landslides in urban Nagaoka was small compared with landslides on natural slopes (especially near Yamakoshi), they represent an important case study for urban landslide disasters. Slope instabilities in urban residential areas were classified as: A) landslides in steep embankments; B) landslides in gently sloping artificial valley fills; C) re-activation of old landslides; and D) liquefaction in deep artificial valley fills. All these failures occurred in relatively uniform suburban landscapes, which were significantly modified from the original landforms. Recent destructive earthquakes in Japan caused similar types of slope failures in urban regions, suggesting that lessons from past earthquakes were not implemented. The greatest damage due to type-A failures occurred in the 25-yr old Takamachi residential area, where about 70 of 522 homes were judged to be uninhabitable. Before development, this area was an isolated hill (90 m elevation) with an adjacent terrace (60 m elevation) consisting of gravel, sand, and silt of the lower to middle Pleistocene deposits. Development earthworks removed the hill crest and created a wide plateau (70 m elevation); excavated soil was placed on the perimeter as an embankment. During the earthquake, the embankment slope collapsed, including retaining walls, perimeter road, and homes. The most serious damage occurred in five places around the margin of the plateau corresponding to shallow valley fills (5 to 8 m thick). Earthquake response analyses using an equivalent linear model indicated the amplification of seismic waves at the surface of embankment slopes, and the peak earthquake acceleration exceeded 1 G

  2. Thermal Infrared Anomalies of Several Strong Earthquakes

    PubMed Central

    Wei, Congxin; Guo, Xiao; Qin, Manzhong

    2013-01-01

    In the history of earthquake thermal infrared research, it is undeniable that before and after strong earthquakes there are significant thermal infrared anomalies which have been interpreted as preseismic precursor in earthquake prediction and forecasting. In this paper, we studied the characteristics of thermal radiation observed before and after the 8 great earthquakes with magnitude up to Ms7.0 by using the satellite infrared remote sensing information. We used new types of data and method to extract the useful anomaly information. Based on the analyses of 8 earthquakes, we got the results as follows. (1) There are significant thermal radiation anomalies before and after earthquakes for all cases. The overall performance of anomalies includes two main stages: expanding first and narrowing later. We easily extracted and identified such seismic anomalies by method of “time-frequency relative power spectrum.” (2) There exist evident and different characteristic periods and magnitudes of thermal abnormal radiation for each case. (3) Thermal radiation anomalies are closely related to the geological structure. (4) Thermal radiation has obvious characteristics in abnormal duration, range, and morphology. In summary, we should be sure that earthquake thermal infrared anomalies as useful earthquake precursor can be used in earthquake prediction and forecasting. PMID:24222728

  3. Thermal infrared anomalies of several strong earthquakes.

    PubMed

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

    2013-01-01

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

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

    PubMed

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

    2014-08-21

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

  5. Estimating Casualties for Large Earthquakes Worldwide Using an Empirical Approach

    USGS Publications Warehouse

    Jaiswal, Kishor; Wald, David J.; Hearne, Mike

    2009-01-01

    We developed an empirical country- and region-specific earthquake vulnerability model to be used as a candidate for post-earthquake fatality estimation by the U.S. Geological Survey's Prompt Assessment of Global Earthquakes for Response (PAGER) system. The earthquake fatality rate is based on past fatal earthquakes (earthquakes causing one or more deaths) in individual countries where at least four fatal earthquakes occurred during the catalog period (since 1973). Because only a few dozen countries have experienced four or more fatal earthquakes since 1973, we propose a new global regionalization scheme based on idealization of countries that are expected to have similar susceptibility to future earthquake losses given the existing building stock, its vulnerability, and other socioeconomic characteristics. The fatality estimates obtained using an empirical country- or region-specific model will be used along with other selected engineering risk-based loss models for generation of automated earthquake alerts. These alerts could potentially benefit the rapid-earthquake-response agencies and governments for better response to reduce earthquake fatalities. Fatality estimates are also useful to stimulate earthquake preparedness planning and disaster mitigation. The proposed model has several advantages as compared with other candidate methods, and the country- or region-specific fatality rates can be readily updated when new data become available.

  6. Fault lubrication during earthquakes.

    PubMed

    Di Toro, G; Han, R; Hirose, T; De Paola, N; Nielsen, S; Mizoguchi, K; Ferri, F; Cocco, M; Shimamoto, T

    2011-03-24

    The determination of rock friction at seismic slip rates (about 1 m s(-1)) is of paramount importance in earthquake mechanics, as fault friction controls the stress drop, the mechanical work and the frictional heat generated during slip. Given the difficulty in determining friction by seismological methods, elucidating constraints are derived from experimental studies. Here we review a large set of published and unpublished experiments (∼300) performed in rotary shear apparatus at slip rates of 0.1-2.6 m s(-1). The experiments indicate a significant decrease in friction (of up to one order of magnitude), which we term fault lubrication, both for cohesive (silicate-built, quartz-built and carbonate-built) rocks and non-cohesive rocks (clay-rich, anhydrite, gypsum and dolomite gouges) typical of crustal seismogenic sources. The available mechanical work and the associated temperature rise in the slipping zone trigger a number of physicochemical processes (gelification, decarbonation and dehydration reactions, melting and so on) whose products are responsible for fault lubrication. The similarity between (1) experimental and natural fault products and (2) mechanical work measures resulting from these laboratory experiments and seismological estimates suggests that it is reasonable to extrapolate experimental data to conditions typical of earthquake nucleation depths (7-15 km). It seems that faults are lubricated during earthquakes, irrespective of the fault rock composition and of the specific weakening mechanism involved.

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

    USGS Publications Warehouse

    Boyd, Oliver S.

    2012-01-01

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

  8. Faith after an Earthquake: A Longitudinal Study of Religion and Perceived Health before and after the 2011 Christchurch New Zealand Earthquake

    PubMed Central

    Sibley, Chris G.; Bulbulia, Joseph

    2012-01-01

    On 22 February 2011, Christchurch New Zealand (population 367,700) experienced a devastating earthquake, causing extensive damage and killing one hundred and eighty-five people. The earthquake and aftershocks occurred between the 2009 and 2011 waves of a longitudinal probability sample conducted in New Zealand, enabling us to examine how a natural disaster of this magnitude affected deeply held commitments and global ratings of personal health, depending on earthquake exposure. We first investigated whether the earthquake-affected were more likely to believe in God. Consistent with the Religious Comfort Hypothesis, religious faith increased among the earthquake-affected, despite an overall decline in religious faith elsewhere. This result offers the first population-level demonstration that secular people turn to religion at times of natural crisis. We then examined whether religious affiliation was associated with differences in subjective ratings of personal health. We found no evidence for superior buffering from having religious faith. Among those affected by the earthquake, however, a loss of faith was associated with significant subjective health declines. Those who lost faith elsewhere in the country did not experience similar health declines. Our findings suggest that religious conversion after a natural disaster is unlikely to improve subjective well-being, yet upholding faith might be an important step on the road to recovery. PMID:23227147

  9. Earthquake likelihood model testing

    USGS Publications Warehouse

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

    2007-01-01

    wide range of possible testing procedures exist. Jolliffe and Stephenson (2003) present different forecast verifications from atmospheric science, among them likelihood testing of probability forecasts and testing the occurrence of binary events. Testing binary events requires that for each forecasted event, the spatial, temporal and magnitude limits be given. Although major earthquakes can be considered binary events, the models within the RELM project express their forecasts on a spatial grid and in 0.1 magnitude units; thus the results are a distribution of rates over space and magnitude. These forecasts can be tested with likelihood tests.In general, likelihood tests assume a valid null hypothesis against which a given hypothesis is tested. The outcome is either a rejection of the null hypothesis in favor of the test hypothesis or a nonrejection, meaning the test hypothesis cannot outperform the null hypothesis at a given significance level. Within RELM, there is no accepted null hypothesis and thus the likelihood test needs to be expanded to allow comparable testing of equipollent hypotheses.To test models against one another, we require that forecasts are expressed in a standard format: the average rate of earthquake occurrence within pre-specified limits of hypocentral latitude, longitude, depth, magnitude, time period, and focal mechanisms. Focal mechanisms should either be described as the inclination of P-axis, declination of P-axis, and inclination of the T-axis, or as strike, dip, and rake angles. Schorlemmer and Gerstenberger (2007, this issue) designed classes of these parameters such that similar models will be tested against each other. These classes make the forecasts comparable between models. Additionally, we are limited to testing only what is precisely defined and consistently reported in earthquake catalogs. Therefore it is currently not possible to test such information as fault rupture length or area, asperity location, etc. Also, to account

  10. A coccidioidomycosis outbreak following the Northridge, Calif, earthquake

    USGS Publications Warehouse

    Schneider, E.; Hajjeh, R.A.; Spiegel, R.A.; Jibson, R.W.; Harp, E.L.; Marshall, G.A.; Gunn, R.A.; McNeil, M.M.; Pinner, R.W.; Baron, R.C.; Burger, R.C.; Hutwagner, L.C.; Crump, C.; Kaufman, L.; Reef, S.E.; Feldman, G.M.; Pappagianis, D.; Werner, S.B.

    1997-01-01

    Objective. - To describe a coccidioidomycosis outbreak in Ventura County following the January 1994 earthquake, centered in Northridge, Calif, and to identify factors that increased the risk for acquiring acute coccidioidomycosis infection. Design. - Epidemic investigation, population- based skin test survey, and case-control study. Setting. - Ventura County, California. Results. - In Ventura County, between January 24 and March 15, 1994, 203 outbreak-associated coccidioidomycosis cases, including 3 fatalities, were identified (attack rate [AR], 30 cases per 100 000 population). The majority of cases (56%) and the highest AR (114 per 100 000 population) occurred in the town of Simi Valley, a community located at the base of a mountain range that experienced numerous landslides associated with the earthquake. Disease onset for cases peaked 2 weeks after the earthquake. The AR was 2.8 times greater for persons 40 years of age and older than for younger persons (relative risk, 2.8; 95% confidence interval [CI], 2.1-3.7; P<.001). Environmental data indicated that large dust clouds, generated by landslides following the earthquake and strong aftershocks in the Santa Susana Mountains north of Simi Valley, were dispersed into nearby valleys by northeast winds. Simi Valley case-control study data indicated that physically being in a dust cloud (odds ratio, 3.0; 95% CI, 1.6-5.4; P<.001) and time spent in a dust cloud (P<.001) significantly increased the risk for being diagnosed with acute coccidioidomycosis. Conclusions. - Both the location and timing of cases strongly suggest that the coccidioidomycosis outbreak in Ventura County was caused when arthrospores were spread in dust clouds generated by the earthquake. This is the first report of a coccidioidomycosis outbreak following an earthquake. Public and physician awareness, especially in endemic areas following similar dust cloud- generating events, may result in prevention and early recognition of acute

  11. Late Holocene paleoseismology of Shuyak Island, Kodiak Archipelago, Alaska - surface deformation and plate segmentation within the 1964 Alaska M 9.2 earthquake rupture zone

    NASA Astrophysics Data System (ADS)

    Brader, Martin; Shennan, Ian; Barlow, Natasha; Davies, Frank; Longley, Chris; Tunstall, Neil

    2017-04-01

    Recent paleoseismological studies question whether segment boundaries identified for 20th and 21st century great, >M 8, earthquakes persist through multiple earthquake cycles, or whether smaller segments with different boundaries rupture and cause significant hazards. The smaller segments may include some that are currently slipping rather than locked. The 1964 Alaska M 9.2 earthquake was the largest of five earthquakes of >M 7.9 between 1938 and 1965 along the Aleutian chain and coast of southcentral Alaska that helped define models of rupture segments along the Alaska-Aleutian megathrust. The 1964 M 9.2 earthquake ruptured ˜950 km of the megathrust, involving two main asperities focussed on Kodiak Island and Prince William Sound and crossed the Kenai segment, which is currently creeping. Paleoseismic studies of coastal sediments currently provide a long record of previous large earthquakes for the Prince William Sound segment, with widespread evidence of seven great earthquakes in the last 4000 years and more restricted evidence for three earlier ones. Shorter and more fragmentary records from the Kenai Peninsula, Yakataga and Kodiak Archipelago raise the hypothesis of different patterns of surface deformation during past great earthquakes. We present new evidence from coastal wetlands on Shuyak Island, towards the hypothesised north-eastern boundary of the Kodiak segment, to illustrate different detection limits of paleoseismic indicators and how these influence the identification of segment boundaries in late Holocene earthquakes. We compare predictions of co-seismic uplift and subsidence derived from geophysical models of earthquakes with different rupture modes. The spatial patterns of agreement and misfit between model predictions and quantitative reconstructions of co-seismic submergence and emergence suggest that no earthquake within the last 4000 years had the same rupture pattern as the 1964 M 9.2 earthquake.

  12. The search for Infrared radiation prior to major earthquakes

    NASA Astrophysics Data System (ADS)

    Ouzounov, D.; Taylor, P.; Pulinets, S.

    2004-12-01

    This work describes our search for a relationship between tectonic stresses and electro-chemical and thermodynamic processes in the Earth and increases in mid-IR flux as part of a possible ensemble of electromagnetic (EM) phenomena that may be related to earthquake activity. Recent analysis of continuous ongoing long- wavelength Earth radiation (OLR) indicates significant and anomalous variability prior to some earthquakes. The cause of these anomalies is not well understood but could be the result of a triggering by an interaction between the lithosphere-hydrosphere and atmospheric related to changes in the near surface electrical field and gas composition prior to the earthquake. The OLR anomaly covers large areas surrounding the main epicenter. We have use the NOAA IR data to differentiate between the global and seasonal variability and these transient local anomalies. Indeed, on the basis of a temporal and spatial distribution analysis, an anomaly pattern is found to occur several days prior some major earthquakes. The significance of these observations was explored using data sets of some recent worldwide events.

  13. Predictability of population displacement after the 2010 Haiti earthquake

    PubMed Central

    Lu, Xin; Bengtsson, Linus; Holme, Petter

    2012-01-01

    Most severe disasters cause large population movements. These movements make it difficult for relief organizations to efficiently reach people in need. Understanding and predicting the locations of affected people during disasters is key to effective humanitarian relief operations and to long-term societal reconstruction. We collaborated with the largest mobile phone operator in Haiti (Digicel) and analyzed the movements of 1.9 million mobile phone users during the period from 42 d before, to 341 d after the devastating Haiti earthquake of January 12, 2010. Nineteen days after the earthquake, population movements had caused the population of the capital Port-au-Prince to decrease by an estimated 23%. Both the travel distances and size of people’s movement trajectories grew after the earthquake. These findings, in combination with the disorder that was present after the disaster, suggest that people’s movements would have become less predictable. Instead, the predictability of people’s trajectories remained high and even increased slightly during the three-month period after the earthquake. Moreover, the destinations of people who left the capital during the first three weeks after the earthquake was highly correlated with their mobility patterns during normal times, and specifically with the locations in which people had significant social bonds. For the people who left Port-au-Prince, the duration of their stay outside the city, as well as the time for their return, all followed a skewed, fat-tailed distribution. The findings suggest that population movements during disasters may be significantly more predictable than previously thought. PMID:22711804

  14. Chronic Trichuris muris Infection in C57BL/6 Mice Causes Significant Changes in Host Microbiota and Metabolome: Effects Reversed by Pathogen Clearance

    PubMed Central

    Houlden, Ashley; Hayes, Kelly S.; Bancroft, Allison J.; Worthington, John J.; Wang, Ping; Grencis, Richard K.; Roberts, Ian S.

    2015-01-01

    Trichuris species are a globally important and prevalent group of intestinal helminth parasites, in which Trichuris muris (mouse whipworm) is an ideal model for this disease. This paper describes the first ever highly controlled and comprehensive investigation into the effects of T. muris infection on the faecal microbiota of mice and the effects on the microbiota following successful clearance of the infection. Communities were profiled using DGGE, 454 pyrosequencing, and metabolomics. Changes in microbial composition occurred between 14 and 28 days post infection, resulting in significant changes in α and β- diversity. This impact was dominated by a reduction in the diversity and abundance of Bacteroidetes, specifically Prevotella and Parabacteroides. Metabolomic analysis of stool samples of infected mice at day 41 showed significant differences to uninfected controls with a significant increase in the levels of a number of essential amino acids and a reduction in breakdown of dietary plant derived carbohydrates. The significant reduction in weight gain by infected mice probably reflects these metabolic changes and the incomplete digestion of dietary polysaccharides. Following clearance of infection the intestinal microbiota underwent additional changes gradually transitioning by day 91 towards a microbiota of an uninfected animal. These data indicate that the changes in microbiota as a consequence of infection were transitory requiring the presence of the pathogen for maintenance. Interestingly this was not observed for all of the key immune cell populations associated with chronic T. muris infection. This reflects the highly regulated chronic response and potential lasting immunological consequences of dysbiosis in the microbiota. Thus infection of T. muris causes a significant and substantial impact on intestinal microbiota and digestive function of mice with affects in long term immune regulation. PMID:25938477

  15. Chronic Trichuris muris Infection in C57BL/6 Mice Causes Significant Changes in Host Microbiota and Metabolome: Effects Reversed by Pathogen Clearance.

    PubMed

    Houlden, Ashley; Hayes, Kelly S; Bancroft, Allison J; Worthington, John J; Wang, Ping; Grencis, Richard K; Roberts, Ian S

    2015-01-01

    Trichuris species are a globally important and prevalent group of intestinal helminth parasites, in which Trichuris muris (mouse whipworm) is an ideal model for this disease. This paper describes the first ever highly controlled and comprehensive investigation into the effects of T. muris infection on the faecal microbiota of mice and the effects on the microbiota following successful clearance of the infection. Communities were profiled using DGGE, 454 pyrosequencing, and metabolomics. Changes in microbial composition occurred between 14 and 28 days post infection, resulting in significant changes in α and β- diversity. This impact was dominated by a reduction in the diversity and abundance of Bacteroidetes, specifically Prevotella and Parabacteroides. Metabolomic analysis of stool samples of infected mice at day 41 showed significant differences to uninfected controls with a significant increase in the levels of a number of essential amino acids and a reduction in breakdown of dietary plant derived carbohydrates. The significant reduction in weight gain by infected mice probably reflects these metabolic changes and the incomplete digestion of dietary polysaccharides. Following clearance of infection the intestinal microbiota underwent additional changes gradually transitioning by day 91 towards a microbiota of an uninfected animal. These data indicate that the changes in microbiota as a consequence of infection were transitory requiring the presence of the pathogen for maintenance. Interestingly this was not observed for all of the key immune cell populations associated with chronic T. muris infection. This reflects the highly regulated chronic response and potential lasting immunological consequences of dysbiosis in the microbiota. Thus infection of T. muris causes a significant and substantial impact on intestinal microbiota and digestive function of mice with affects in long term immune regulation.

  16. Statistical tests of simple earthquake cycle models

    NASA Astrophysics Data System (ADS)

    DeVries, Phoebe M. R.; Evans, Eileen L.

    2016-12-01

    A central goal of observing and modeling the earthquake cycle is to forecast when a particular fault may generate an earthquake: a fault late in its earthquake cycle may be more likely to generate an earthquake than a fault early in its earthquake cycle. Models that can explain geodetic observations throughout the entire earthquake cycle may be required to gain a more complete understanding of relevant physics and phenomenology. Previous efforts to develop unified earthquake models for strike-slip faults have largely focused on explaining both preseismic and postseismic geodetic observations available across a few faults in California, Turkey, and Tibet. An alternative approach leverages the global distribution of geodetic and geologic slip rate estimates on strike-slip faults worldwide. Here we use the Kolmogorov-Smirnov test for similarity of distributions to infer, in a statistically rigorous manner, viscoelastic earthquake cycle models that are inconsistent with 15 sets of observations across major strike-slip faults. We reject a large subset of two-layer models incorporating Burgers rheologies at a significance level of α = 0.05 (those with long-term Maxwell viscosities ηM < 4.0 × 1019 Pa s and ηM > 4.6 × 1020 Pa s) but cannot reject models on the basis of transient Kelvin viscosity ηK. Finally, we examine the implications of these results for the predicted earthquake cycle timing of the 15 faults considered and compare these predictions to the geologic and historical record.

  17. Laboratory generated M -6 earthquakes

    USGS Publications Warehouse

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

    2014-01-01

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

  18. The Human Impact of Earthquakes: a Historical Review of Events 1980-2009 and Systematic Literature Review

    PubMed Central

    Doocy, Shannon; Daniels, Amy; Packer, Catherine; Dick, Anna; Kirsch, Thomas D.

    2013-01-01

    Introduction. Population growth and increasing urbanization in earthquake-prone areas suggest that earthquake impacts on human populations will increase in the coming decades. Recent large earthquakes affecting large populations in Japan, Haiti, Chile and New Zealand are evidence of this trend and also illustrate significant variations in outcomes such damage and mortality levels. The objectives of this review were to describe the impact of earthquakes on human populations in terms of mortality, injury and displacement and, to the extent possible, identify risk factors associated with these outcomes. This is one of five reviews on the human impact of natural disasters. Methods. Data on the impact of earthquakes were compiled using two methods, a historical review from 1980 to mid 2009 of earthquake events from multiple databases and a systematic literature review of publications, ending in October 2012. Analysis included descriptive statistics and bivariate tests for associations between earthquake mortality and characteristics using STATA 11. Findings. From 1980 through 2009, there were a total of 372,634 deaths (range 314,634-412,599), 995,219 injuries (range: 845,345-1,145,093), and more than 61 million people affected by earthquakes, and mortality was greatest in Asia. Inconsistent reporting across data sources suggests that the numbers injured and affected are likely underestimates. Findings from a systematic review of the literature indicate that the primary cause of earthquake-related death was trauma due to building collapse and, the very young and the elderly were at increased mortality risk, while gender was not consistently associated with mortality risk. Conclusions. Strategies to mitigate the impact of future earthquakes should include improvements to the built environment and a focus on populations most vulnerable to mortality and injury. PMID:23857161

  19. Pre-earthquake multiparameter analysis of the 2016 Amatrice-Norcia (Central Italy) seismic sequence: a case study for the application of the SAFE project concepts

    NASA Astrophysics Data System (ADS)

    De Santis, A.

    2017-12-01

    The SAFE (Swarm for Earthquake study) project (funded by European Space Agency in the framework "STSE Swarm+Innovation", 2014-2016) aimed at applying the new approach of geosystemics to the analysis of Swarm satellite (ESA) electromagnetic data for investigating the preparatory phase of earthquakes. We present in this talk the case study of the most recent seismic sequence in Italy. First a M6 earthquake on 24 August 2016 and then a M6.5 earthquake on 30 October 2016 shocked almost in the same region of Central Italy causing about 300 deaths in total (mostly on 24 August), with a revival of other significant seismicity on January 2017. Analysing both geophysical and climatological satellite and ground data preceding the major earthquakes of the sequence we present results that confirm a complex solid earth-atmosphere coupling in the preparation phase of the whole sequence.

  20. 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

  1. 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.

  2. Earthquakes: hydrogeochemical precursors

    USGS Publications Warehouse

    Ingebritsen, Steven E.; Manga, Michael

    2014-01-01

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

  3. 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.

  4. 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.

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

    PubMed

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

    1986-07-25

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

  6. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2012-12-01

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

  8. 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

  9. 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.

  10. Redefining Earthquakes and the Earthquake Machine

    ERIC Educational Resources Information Center

    Hubenthal, Michael; Braile, Larry; Taber, John

    2008-01-01

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

  11. SITE AMPLIFICATION OF EARTHQUAKE GROUND MOTION.

    USGS Publications Warehouse

    Hays, Walter W.

    1986-01-01

    When analyzing the patterns of damage in an earthquake, physical parameters of the total earthquake-site-structure system are correlated with the damage. Soil-structure interaction, the cause of damage in many earthquakes, involves the frequency-dependent response of both the soil-rock column and the structure. The response of the soil-rock column (called site amplification) is controversial because soil has strain-dependent properties that affect the way the soil column filters the input body and surface seismic waves, modifying the amplitude and phase spectra and the duration of the surface ground motion.

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

    NASA Astrophysics Data System (ADS)

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

    2013-05-01

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

  13. Important Earthquake Engineering Resources

    Science.gov Websites

    PEER logo Pacific Earthquake Engineering Research Center home about peer news events research Engineering Resources Site Map Search Important Earthquake Engineering Resources - American Concrete Institute Motion Observation Systems (COSMOS) - Consortium of Universities for Research in Earthquake Engineering

  14. 2016 National Earthquake Conference

    Science.gov Websites

    Thank you to our Presenting Sponsor, California Earthquake Authority. What's New? What's Next ? What's Your Role in Building a National Strategy? The National Earthquake Conference (NEC) is a , state government leaders, social science practitioners, U.S. State and Territorial Earthquake Managers

  15. Can We Predict Earthquakes?

    ScienceCinema

    Johnson, Paul

    2018-01-16

    The only thing we know for sure about earthquakes is that one will happen again very soon. Earthquakes pose a vital yet puzzling set of research questions that have confounded scientists for decades, but new ways of looking at seismic information and innovative laboratory experiments are offering tantalizing clues to what triggers earthquakes — and when.

  16. Earthquake and Schools. [Videotape].

    ERIC Educational Resources Information Center

    Federal Emergency Management Agency, Washington, DC.

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

  17. 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…

  18. The 2017 Mw = 8.2 Tehuantepec earthquake: a slab bending or slab pull rupture?

    NASA Astrophysics Data System (ADS)

    Duputel, Z.; Gombert, B.; Simons, M.; Fielding, E. J.; Rivera, L. A.; Bekaert, D. P.; Jiang, J.; Liang, C.; Moore, A. W.; Liu, Z.

    2017-12-01

    On September 8th 2017, a regionally destructive Mw 8.2 intra-slab earthquake struck Mexico in the Gulf of Tehuantepec. While large intermediate depth intra-slab earthquakes are a major hazard, we have only a limited knowledge of the strain budgets within subducting slabs. Several mechanisms have been proposed to explain intraplate earthquakes in subduction zones. Bending stresses might cause the occurrence of seismic events located at depths where the slab dip changes abruptly. However, an alternative explanation is needed if the ruptures are found to propagate through the entire lithosphere. Depending on the coupling of the subduction interface, intraplate earthquakes occurring updip or downdip of the locked zone could also be caused by the negative buoyancy of the sinking slab (i.e., slab pull). The increasing availability of near-fault data provides a unique opportunity to better constrain the seismogenic behavior of large intra-slab earthquakes. Teleseismic analyses of the 2017 Tehuantepec earthquake lead to contrasting statements about the depth extent of the rupture: while most of long period centroid moment tensor inversions yield fairly large centroid depths (>40 km), some finite-fault models suggest much shallower slip concentrated at depths less than 30 km. In this study, we analyze GPS, InSAR, tsunami and seismological data to constrain the earthquake location, fault geometry and slip distribution. We use a Bayesian approach devoid of significant spatial smoothing to characterize the range of allowable rupture depths. In addition, to cope with potential artifacts in centroid depth estimates due to unmodeled lateral heterogeneities, we also analyze long-period seismological data using a full 3D Earth model. Preliminary results suggest a fairly deep rupture consistent with a slab-pull process breaking a significant proportion of the lithosphere and potentially reflecting at least local detachment of the slab.

  19. Operational earthquake forecasting can enhance earthquake preparedness

    USGS Publications Warehouse

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

    2014-01-01

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

  20. Heterogeneous carbonaceous matter in sedimentary rock lithocomponents causes significant trichloroethylene (TCE) sorption in a low organic carbon content aquifer/aquitard system

    NASA Astrophysics Data System (ADS)

    Choung, Sungwook; Zimmerman, Lisa R.; Allen-King, Richelle M.; Ligouis, Bertrand; Feenstra, Stanley

    2014-10-01

    This study evaluated the effects of heterogeneous thermally altered carbonaceous matter (CM) on trichloroethylene (TCE) sorption for a low fraction organic carbon content (foc) alluvial sedimentary aquifer and aquitard system (foc = 0.046-0.105%). The equilibrium TCE sorption isotherms were highly nonlinear with Freundlich exponents of 0.46-0.58. Kerogen + black carbon was the dominant CM fraction extracted from the sediments and accounted for > 60% and 99% of the total in the sands and silt, respectively. Organic petrological examination determined that the kerogen included abundant amorphous organic matter (bituminite), likely of marine origin. The dark calcareous siltstone exhibited the greatest TCE sorption among aquifer lithocomponents and accounted for most sorption in the aquifer. The results suggest that the source of the thermally altered CM, which causes nonlinear sorption, was derived from parent Paleozoic marine carbonate rocks that outcrop throughout much of New York State. A synthetic aquifer-aquitard unit system (10% aquitard) was used to illustrate the effect of the observed nonlinear sorption on mass storage potential at equilibrium. The calculation showed that > 80% of TCE mass contained in the aquifer was sorbed on the aquifer sediment at aqueous concentration < 1000 μg L- 1. These results show that sorption is likely a significant contributor to the persistence of a TCE groundwater plume in the aquifer studied. It is implied that sorption may similarly contribute to TCE persistence in other glacial alluvial aquifers with similar geologic characteristics, i.e., comprised of sedimentary rock lithocomponents that contain thermally altered CM.

  1. Tremors behind the power outlet - where earthquakes appear on our monthly bill

    NASA Astrophysics Data System (ADS)

    Baisch, Stefan

    2013-04-01

    The world's appetite for energy has significantly increased over the last decades, not least due to the rapid growth of Asian economies. In parallel, the Fukushima shock raised widespread concerns against nuclear power generation and an increasing desire for clean energy technologies. To solve the conflict of higher demands, limited resources and a growing level of green consciousness, both up-scaling of conventional and development of renewable energy technologies are required. This is where the phenomenon of man-made earthquakes appears on the radar screen. Several of our energy production technologies have the potential to cause small, moderate, or sometimes even larger magnitude earthquakes. There is a general awareness that coal mining activities can produce moderate sized earthquakes. Similarly, long-term production from hydrocarbon reservoirs can lead to subsurface deformations accompanied by even larger magnitude earthquakes. Even the "renewables" are not necessarily earthquake-free. Several of the largest man-made earthquakes have been caused by water impoundment for hydropower plants. On a much smaller scale, micro earthquakes can occur in enhanced geothermal systems (EGS). Although still in its infancy, the EGS technology has an enormous potential to supply base load electricity, and its technical feasibility for a large scale application is currently being investigated in about a dozen pilot projects. The principal concept of heat extraction by circulating water through a subsurface reservoir is fairly simple, the technical implementation of EGS, however, exhibits several challenges not all of which are yet being solved. As the hydraulic conductivity at depth is usually extremely low at EGS sites, a technical stimulation of hydraulic pathways is required for creating an artificial heat exchanger. By injecting fluid under high pressure into the subsurface, tectonic stress on existing fractures can be released and the associated shearing of the fractures

  2. Living on an Active Earth: Perspectives on Earthquake Science

    NASA Astrophysics Data System (ADS)

    Lay, Thorne

    2004-02-01

    The annualized long-term loss due to earthquakes in the United States is now estimated at $4.4 billion per year. A repeat of the 1923 Kanto earthquake, near Tokyo, could cause direct losses of $2-3 trillion. With such grim numbers, which are guaranteed to make you take its work seriously, the NRC Committee on the Science of Earthquakes begins its overview of the emerging multidisciplinary field of earthquake science. An up-to-date and forward-looking survey of scientific investigation of earthquake phenomena and engineering response to associated hazards is presented at a suitable level for a general educated audience. Perspectives from the fields of seismology, geodesy, neo-tectonics, paleo-seismology, rock mechanics, earthquake engineering, and computer modeling of complex dynamic systems are integrated into a balanced definition of earthquake science that has never before been adequately articulated.

  3. Earthquakes May-June 1980.

    USGS Publications Warehouse

    Person, W.J.

    1981-01-01

    The months were seismically active, although only one major event (7.0-7.9) occurred in an unpopulated Philippine Island. Mexico was struck by a 6.3 quake on June 9 killing at least two people. The most significant earthquake in the United States was in the Mammoth Lakes area of California. -from Author

  4. Injuries and Traumatic Psychological Exposures Associated with the South Napa Earthquake - California, 2014.

    PubMed

    Attfield, Kathleen R; Dobson, Christine B; Henn, Jennifer B; Acosta, Meileen; Smorodinsky, Svetlana; Wilken, Jason A; Barreau, Tracy; Schreiber, Merritt; Windham, Gayle C; Materna, Barbara L; Roisman, Rachel

    2015-09-11

    On August 24, 2014, at 3:20 a.m., a magnitude 6.0 earthquake struck California, with its epicenter in Napa County (1). The earthquake was the largest to affect the San Francisco Bay area in 25 years and caused significant damage in Napa and Solano counties, including widespread power outages, five residential fires, and damage to roadways, waterlines, and 1,600 buildings (2). Two deaths resulted (2). On August 25, Napa County Public Health asked the California Department of Public Health (CDPH) for assistance in assessing postdisaster health effects, including earthquake-related injuries and effects on mental health. On September 23, Solano County Public Health requested similar assistance. A household-level Community Assessment for Public Health Emergency Response (CASPER) was conducted for these counties in two cities (Napa, 3 weeks after the earthquake, and Vallejo, 6 weeks after the earthquake). Among households reporting injuries, a substantial proportion (48% in Napa and 37% in western Vallejo) reported that the injuries occurred during the cleanup period, suggesting that increased messaging on safety precautions after a disaster might be needed. One fifth of respondents overall (27% in Napa and 9% in western Vallejo) reported one or more traumatic psychological exposures in their households. These findings were used by Napa County Mental Health to guide immediate-term mental health resource allocations and to conduct public training sessions and education campaigns to support persons with mental health risks following the earthquake. In addition, to promote community resilience and future earthquake preparedness, Napa County Public Health subsequently conducted community events on the earthquake anniversary and provided outreach workers with psychological first aid training.

  5. Brady's Geothermal Field DAS Earthquake Data

    SciTech Connect

    Kurt Feigl

    The submitted data correspond to the vibration caused by a 3.4 M earthquake and captured by the DAS horizontal and vertical arrays during the PoroTomo Experiment. Earthquake information : M 4.3 - 23km ESE of Hawthorne, Nevada Time: 2016-03-21 07:37:10 (UTC) Location: 38.479 N 118.366 W Depth: 9.9 km

  6. Satellite Infrared Radiation Measurements Prior to the Major Earthquakes

    NASA Technical Reports Server (NTRS)

    Ouzounov, Dimitar; Pulintes, S.; Bryant, N.; Taylor, Patrick; Freund, F.

    2005-01-01

    This work describes our search for a relationship between tectonic stresses and increases in mid-infrared (IR) flux as part of a possible ensemble of electromagnetic (EM) phenomena that may be related to earthquake activity. We present and &scuss observed variations in thermal transients and radiation fields prior to the earthquakes of Jan 22, 2003 Colima (M6.7) Mexico, Sept. 28 .2004 near Parkfield (M6.0) in California and Northern Sumatra (M8.5) Dec. 26,2004. Previous analysis of earthquake events has indicated the presence of an IR anomaly, where temperatures increased or did not return to its usual nighttime value. Our procedures analyze nighttime satellite data that records the general condtion of the ground after sunset. We have found from the MODIS instrument data that five days before the Colima earthquake the IR land surface nighttime temperature rose up to +4 degrees C in a 100 km radius around the epicenter. The IR transient field recorded by MODIS in the vicinity of Parkfield, also with a cloud free environment, was around +1 degree C and is significantly smaller than the IR anomaly around the Colima epicenter. Ground surface temperatures near the Parkfield epicenter four days prior to the earthquake show steady increase. However, on the night preceding the quake, a significant drop in relative humidity was indicated, process similar to those register prior to the Colima event. Recent analyses of continuous ongoing long- wavelength Earth radiation (OLR) indicate significant and anomalous variability prior to some earthquakes. The cause of these anomalies is not well understood but could be the result of a triggering by an interaction between the lithosphere-hydrosphere and atmospheric related to changes in the near surface electrical field and/or gas composition prior to the earthquake. The OLR anomaly usually covers large areas surrounding the main epicenter. We have found strong anomalies signal (two sigma) along the epicentral area signals on Dec 21

  7. Probing failure susceptibilities of earthquake faults using small-quake tidal correlations.

    PubMed

    Brinkman, Braden A W; LeBlanc, Michael; Ben-Zion, Yehuda; Uhl, Jonathan T; Dahmen, Karin A

    2015-01-27

    Mitigating the devastating economic and humanitarian impact of large earthquakes requires signals for forecasting seismic events. Daily tide stresses were previously thought to be insufficient for use as such a signal. Recently, however, they have been found to correlate significantly with small earthquakes, just before large earthquakes occur. Here we present a simple earthquake model to investigate whether correlations between daily tidal stresses and small earthquakes provide information about the likelihood of impending large earthquakes. The model predicts that intervals of significant correlations between small earthquakes and ongoing low-amplitude periodic stresses indicate increased fault susceptibility to large earthquake generation. The results agree with the recent observations of large earthquakes preceded by time periods of significant correlations between smaller events and daily tide stresses. We anticipate that incorporating experimentally determined parameters and fault-specific details into the model may provide new tools for extracting improved probabilities of impending large earthquakes.

  8. Bayesian exploration of recent Chilean earthquakes

    NASA Astrophysics Data System (ADS)

    Duputel, Zacharie; Jiang, Junle; Jolivet, Romain; Simons, Mark; Rivera, Luis; Ampuero, Jean-Paul; Liang, Cunren; Agram, Piyush; Owen, Susan; Ortega, Francisco; Minson, Sarah

    2016-04-01

    The South-American subduction zone is an exceptional natural laboratory for investigating the behavior of large faults over the earthquake cycle. It is also a playground to develop novel modeling techniques combining different datasets. Coastal Chile was impacted by two major earthquakes in the last two years: the 2015 M 8.3 Illapel earthquake in central Chile and the 2014 M 8.1 Iquique earthquake that ruptured the central portion of the 1877 seismic gap in northern Chile. To gain better understanding of the distribution of co-seismic slip for those two earthquakes, we derive joint kinematic finite fault models using a combination of static GPS offsets, radar interferograms, tsunami measurements, high-rate GPS waveforms and strong motion data. Our modeling approach follows a Bayesian formulation devoid of a priori smoothing thereby allowing us to maximize spatial resolution of the inferred family of models. The adopted approach also attempts to account for major sources of uncertainty in the Green's functions. The results reveal different rupture behaviors for the 2014 Iquique and 2015 Illapel earthquakes. The 2014 Iquique earthquake involved a sharp slip zone and did not rupture to the trench. The 2015 Illapel earthquake nucleated close to the coast and propagated toward the trench with significant slip apparently reaching the trench or at least very close to the trench. At the inherent resolution of our models, we also present the relationship of co-seismic models to the spatial distribution of foreshocks, aftershocks and fault coupling models.

  9. Scoring annual earthquake predictions in China

    NASA Astrophysics Data System (ADS)

    Zhuang, Jiancang; Jiang, Changsheng

    2012-02-01

    The Annual Consultation Meeting on Earthquake Tendency in China is held by the China Earthquake Administration (CEA) in order to provide one-year earthquake predictions over most China. In these predictions, regions of concern are denoted together with the corresponding magnitude range of the largest earthquake expected during the next year. Evaluating the performance of these earthquake predictions is rather difficult, especially for regions that are of no concern, because they are made on arbitrary regions with flexible magnitude ranges. In the present study, the gambling score is used to evaluate the performance of these earthquake predictions. Based on a reference model, this scoring method rewards successful predictions and penalizes failures according to the risk (probability of being failure) that the predictors have taken. Using the Poisson model, which is spatially inhomogeneous and temporally stationary, with the Gutenberg-Richter law for earthquake magnitudes as the reference model, we evaluate the CEA predictions based on 1) a partial score for evaluating whether issuing the alarmed regions is based on information that differs from the reference model (knowledge of average seismicity level) and 2) a complete score that evaluates whether the overall performance of the prediction is better than the reference model. The predictions made by the Annual Consultation Meetings on Earthquake Tendency from 1990 to 2003 are found to include significant precursory information, but the overall performance is close to that of the reference model.

  10. 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.

  11. New ideas about the physics of earthquakes

    NASA Astrophysics Data System (ADS)

    Rundle, John B.; Klein, William

    1995-07-01

    It may be no exaggeration to claim that this most recent quaddrenium has seen more controversy and thus more progress in understanding the physics of earthquakes than any in recent memory. The most interesting development has clearly been the emergence of a large community of condensed matter physicists around the world who have begun working on the problem of earthquake physics. These scientists bring to the study of earthquakes an entirely new viewpoint, grounded in the physics of nucleation and critical phenomena in thermal, magnetic, and other systems. Moreover, a surprising technology transfer from geophysics to other fields has been made possible by the realization that models originally proposed to explain self-organization in earthquakes can also be used to explain similar processes in problems as disparate as brain dynamics in neurobiology (Hopfield, 1994), and charge density waves in solids (Brown and Gruner, 1994). An entirely new sub-discipline is emerging that is focused around the development and analysis of large scale numerical simulations of the dynamics of faults. At the same time, intriguing new laboratory and field data, together with insightful physical reasoning, has led to significant advances in our understanding of earthquake source physics. As a consequence, we can anticipate substantial improvement in our ability to understand the nature of earthquake occurrence. Moreover, while much research in the area of earthquake physics is fundamental in character, the results have many potential applications (Cornell et al., 1993) in the areas of earthquake risk and hazard analysis, and seismic zonation.

  12. Crowdsourced earthquake early warning

    PubMed Central

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

    2015-01-01

    Earthquake early warning (EEW) can reduce harm to people and infrastructure from earthquakes and tsunamis, but it has not been implemented in most high earthquake-risk regions because of prohibitive cost. Common consumer devices such as smartphones contain low-cost versions of the sensors used in EEW. Although less accurate than scientific-grade instruments, these sensors are globally ubiquitous. Through controlled tests of consumer devices, simulation of an Mw (moment magnitude) 7 earthquake on California’s Hayward fault, and real data from the Mw 9 Tohoku-oki earthquake, we demonstrate that EEW could be achieved via crowdsourcing. PMID:26601167

  13. Crowdsourced earthquake early warning.

    PubMed

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

    2015-04-01

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

  14. Crowdsourced earthquake early warning

    USGS Publications Warehouse

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

    2015-01-01

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

  15. Changes in environment, climate, land-use and population growth cause significant change in recharge on the western coast of Saudi Arabia

    NASA Astrophysics Data System (ADS)

    Prein, Angela; Weiß, Johannes

    2013-04-01

    calibration. Thus, from the groundwater rise with known storage coefficients the leakage was estimated and checked for plausibility. Model evaluation and sensitivity analysis include the identification of key model parameters, the parameter ranges for the prediction of groundwater levels and the characterization of associated uncertainties. The modelling results show that indeed the anthropogenic recharge caused by leakage from water infrastructure is the most important source of groundwater level rise. Thus, to improve model accuracy, a methodology is needed to cope with limited data availability regarding the leakage from pipelines. For the design of future management strategies, modelling scenarios are used to quantify the factors with possible impacts on groundwater levels, including Red Sea water level rise due to climate change, as well as potentially significant changes in land use, water distribution systems, waste water management, storm water and flood control, and irrigation. The model results are used for the design of a field-based groundwater and surface water monitoring system. Based on these measurements, a decision support system for future groundwater control is planned to be integrated into the upgrade of the water and waste water master plan.

  16. Energy Partition and Variability of Earthquakes

    NASA Astrophysics Data System (ADS)

    Kanamori, H.

    2003-12-01

    mechanically dissipated during faulting. In the context of the slip-weakening model, EG can be estimated from Δ W0 and ER. Alternatively, EG can be estimated from the laboratory data on the surface energy, the grain size and the total volume of newly formed fault gouge. This method suggests that, for crustal earthquakes, EG/E_R is very small, less than 0.2 even for extreme cases, for earthquakes with MW>7. This is consistent with the EG estimated with seismological methods, and the fast rupture speeds during most large earthquakes. For shallow subduction-zone earthquakes, EG/E_R varies substantially depending on the tectonic environments. EH: Direct estimation of EH is difficult. However, even with modest friction, EH can be very large, enough to melt or even dissociate a significant amount of material near the slip zone for large events with large slip, and the associated thermal effects may have significant effects on fault dynamics. The energy partition varies significantly for different types of earthquakes, e.g. large earthquakes on mature faults, large earthquakes on faults with low slip rates, subduction-zone earthquakes, deep focus earthquakes etc; this variability manifests itself in the difference in the evolution of seismic slip pattern. The different behaviors will be illustrated using the examples for large earthquakes, including, the 2001 Kunlun, the 1998 Balleny Is., the 1994 Bolivia, the 2001 India earthquake, the 1999 Chi-Chi, and the 2002 Denali earthquakes.

  17. Heterogeneous carbonaceous matter in sedimentary rock lithocomponents causes significant trichloroethylene (TCE) sorption in a low organic carbon content aquifer/aquitard system.

    PubMed

    Choung, Sungwook; Zimmerman, Lisa R; Allen-King, Richelle M; Ligouis, Bertrand; Feenstra, Stanley

    2014-10-15

    This study evaluated the effects of heterogeneous thermally altered carbonaceous matter (CM) on trichloroethylene (TCE) sorption for a low fraction organic carbon content (foc) alluvial sedimentary aquifer and aquitard system (foc=0.046-0.105%). The equilibrium TCE sorption isotherms were highly nonlinear with Freundlich exponents of 0.46-0.58. Kerogen+black carbon was the dominant CM fraction extracted from the sediments and accounted for >60% and 99% of the total in the sands and silt, respectively. Organic petrological examination determined that the kerogen included abundant amorphous organic matter (bituminite), likely of marine origin. The dark calcareous siltstone exhibited the greatest TCE sorption among aquifer lithocomponents and accounted for most sorption in the aquifer. The results suggest that the source of the thermally altered CM, which causes nonlinear sorption, was derived from parent Paleozoic marine carbonate rocks that outcrop throughout much of New York State. A synthetic aquifer-aquitard unit system (10% aquitard) was used to illustrate the effect of the observed nonlinear sorption on mass storage potential at equilibrium. The calculation showed that >80% of TCE mass contained in the aquifer was sorbed on the aquifer sediment at aqueous concentration <1000 μgL(-1). These results show that sorption is likely a significant contributor to the persistence of a TCE groundwater plume in the aquifer studied. It is implied that sorption may similarly contribute to TCE persistence in other glacial alluvial aquifers with similar geologic characteristics, i.e., comprised of sedimentary rock lithocomponents that contain thermally altered CM. Copyright © 2014 Elsevier B.V. All rights reserved.

  18. Significant Reduction of Brain Cysts Caused by Toxoplasma gondii after Treatment with Spiramycin Coadministered with Metronidazole in a Mouse Model of Chronic Toxoplasmosis

    PubMed Central

    Chew, Wai Kit; Ambu, Stephen; Mak, Joon Wah

    2012-01-01

    Toxoplasma gondii is a parasite that generates latent cysts in the brain; reactivation of these cysts may lead to fatal toxoplasmic encephalitis, for which treatment remains unsuccessful. We assessed spiramycin pharmacokinetics coadministered with metronidazole, the eradication of brain cysts and the in vitro reactivation. Male BALB/c mice were fed 1,000 tachyzoites orally to develop chronic toxoplasmosis. Four weeks later, infected mice underwent different treatments: (i) infected untreated mice (n = 9), which received vehicle only; (ii) a spiramycin-only group (n = 9), 400 mg/kg daily for 7 days; (iii) a metronidazole-only group (n = 9), 500 mg/kg daily for 7 days; and (iv) a combination group (n = 9), which received both spiramycin (400 mg/kg) and metronidazole (500 mg/kg) daily for 7 days. An uninfected control group (n = 10) was administered vehicle only. After treatment, the brain cysts were counted, brain homogenates were cultured in confluent Vero cells, and cysts and tachyzoites were counted after 1 week. Separately, pharmacokinetic profiles (plasma and brain) were assessed after a single dose of spiramycin (400 mg/kg), metronidazole (500 mg/kg), or both. Metronidazole treatment increased the brain spiramycin area under the concentration-time curve from 0 h to ∞ (AUC0–∞) by 67% without affecting its plasma disposition. Metronidazole plasma and brain AUC0–∞ values were reduced 9 and 62%, respectively, after spiramycin coadministration. Enhanced spiramycin brain exposure after coadministration reduced brain cysts 15-fold (79 ± 23 for the combination treatment versus 1,198 ± 153 for the untreated control group [P < 0.05]) and 10-fold versus the spiramycin-only group (768 ± 125). Metronidazole alone showed no effect (1,028 ± 149). Tachyzoites were absent in the brain. Spiramycin reduced in vitro reactivation. Metronidazole increased spiramycin brain penetration, causing a significant reduction of T. gondii brain cysts, with potential clinical

  19. 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

    . 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.

  20. Statistical earthquake focal mechanism forecasts

    NASA Astrophysics Data System (ADS)

    Kagan, Yan Y.; Jackson, David D.

    2014-04-01

    Forecasts of the focal mechanisms of future shallow (depth 0-70 km) earthquakes are important for seismic hazard estimates and Coulomb stress, and other models of earthquake occurrence. Here we report on a high-resolution global forecast of earthquake rate density as a function of location, magnitude and focal mechanism. In previous publications we reported forecasts of 0.5° spatial resolution, covering the latitude range from -75° to +75°, based on the Global Central Moment Tensor earthquake catalogue. In the new forecasts we have improved the spatial resolution to 0.1° and the latitude range from pole to pole. Our focal mechanism estimates require distance-weighted combinations of observed focal mechanisms within 1000 km of each gridpoint. Simultaneously, we calculate an average rotation angle between the forecasted mechanism and all the surrounding mechanisms, using the method of Kagan & Jackson proposed in 1994. This average angle reveals the level of tectonic complexity of a region and indicates the accuracy of the prediction. The procedure becomes problematical where longitude lines are not approximately parallel, and where shallow earthquakes are so sparse that an adequate sample spans very large distances. North or south of 75°, the azimuths of points 1000 km away may vary by about 35°. We solved this problem by calculating focal mechanisms on a plane tangent to the Earth's surface at each forecast point, correcting for the rotation of the longitude lines at the locations of earthquakes included in the averaging. The corrections are negligible between -30° and +30° latitude, but outside that band uncorrected rotations can be significantly off. Improved forecasts at 0.5° and 0.1° resolution are posted at http://eq.ess.ucla.edu/kagan/glob_gcmt_index.html.

  1. The Loma Prieta, California, Earthquake of October 17, 1989: Societal Response

    USGS Publications Warehouse

    Coordinated by Mileti, Dennis S.

    1993-01-01

    Professional Paper 1553 describes how people and organizations responded to the earthquake and how the earthquake impacted people and society. The investigations evaluate the tools available to the research community to measure the nature, extent, and causes of damage and losses. They describe human behavior during and immediately after the earthquake and how citizens participated in emergency response. They review the challenges confronted by police and fire departments and disruptions to transbay transportations systems. And they survey the challenges of post-earthquake recovery. Some significant findings were: * Loma Prieta provided the first test of ATC-20, the red, yellow, and green tagging of buildings. It successful application has led to widespread use in other disasters including the September 11, 2001, New York City terrorist incident. * Most people responded calmly and without panic to the earthquake and acted to get themselves to a safe location. * Actions by people to help alleviate emergency conditions were proportional to the level of need at the community level. * Some solutions caused problems of their own. The police perimeter around the Cypress Viaduct isolated businesses from their customers leading to a loss of business and the evacuation of employees from those businesses hindered the movement of supplies to the disaster scene. * Emergency transbay ferry service was established 6 days after the earthquake, but required constant revision of service contracts and schedules. * The Loma Prieta earthquake produced minimal disruption to the regional economy. The total economic disruption resulted in maximum losses to the Gross Regional Product of $725 million in 1 month and $2.9 billion in 2 months, but 80% of the loss was recovered during the first 6 months of 1990. Approximately 7,100 workers were laid off.

  2. Earthquake Occurrence in Bangladesh and Surrounding Region

    NASA Astrophysics Data System (ADS)

    Al-Hussaini, T. M.; Al-Noman, M.

    2011-12-01

    The collision of the northward moving Indian plate with the Eurasian plate is the cause of frequent earthquakes in the region comprising Bangladesh and neighbouring India, Nepal and Myanmar. Historical records indicate that Bangladesh has been affected by five major earthquakes of magnitude greater than 7.0 (Richter scale) during 1869 to 1930. This paper presents some statistical observations of earthquake occurrence in fulfilment of a basic groundwork for seismic hazard assessment of this region. An up to date catalogue covering earthquake information in the region bounded within 17°-30°N and 84°-97°E for the period of historical period to 2010 is derived from various reputed international sources including ISC, IRIS, Indian sources and available publications. Careful scrutiny is done to remove duplicate or uncertain earthquake events. Earthquake magnitudes in the range of 1.8 to 8.1 have been obtained and relationships between different magnitude scales have been studied. Aftershocks are removed from the catalogue using magnitude dependent space window and time window. The main shock data are then analyzed to obtain completeness period for different magnitudes evaluating their temporal homogeneity. Spatial and temporal distribution of earthquakes, magnitude-depth histograms and other statistical analysis are performed to understand the distribution of seismic activity in this region.

  3. Sichuan Earthquake in China

    NASA Technical Reports Server (NTRS)

    2008-01-01

    The Sichuan earthquake in China occurred on May 12, 2008, along faults within the mountains, but near and almost parallel the mountain front, northwest of the city of Chengdu. This major quake caused immediate and severe damage to many villages and cities in the area. Aftershocks pose a continuing danger, but another continuing hazard is the widespread occurrence of landslides that have formed new natural dams and consequently new lakes. These lakes are submerging roads and flooding previously developed lands. But an even greater concern is the possible rapid release of water as the lakes eventually overflow the new dams. The dams are generally composed of disintegrated rock debris that may easily erode, leading to greater release of water, which may then cause faster erosion and an even greater release of water. This possible 'positive feedback' between increasing erosion and increasing water release could result in catastrophic debris flows and/or flooding. The danger is well known to the Chinese earthquake response teams, which have been building spillways over some of the new natural dams.

    This ASTER image, acquired on June 1, 2008, shows two of the new large landslide dams and lakes upstream from the town of Chi-Kua-Kan at 32o12'N latitude and 104o50'E longitude. Vegetation is green, water is blue, and soil is grayish brown in this enhanced color view. New landslides appear bright off-white. The northern (top) lake is upstream from the southern lake. Close inspection shows a series of much smaller lakes in an elongated 'S' pattern along the original stream path. Note especially the large landslides that created the dams. Some other landslides in this area, such as the large one in the northeast corner of the image, occur only on the mountain slopes, so do not block streams, and do not form lakes.

  4. Mega-thrust and Intra-slab Earthquakes Beneath Tokyo Metropolitan Area

    NASA Astrophysics Data System (ADS)

    Hirata, N.; Sato, H.; Koketsu, K.; Hagiwara, H.; Wu, F.; Okaya, D.; Iwasaki, T.; Kasahara, K.

    2006-12-01

    In central Japan the Philippine Sea plate (PSP) subducts beneath the Tokyo Metropolitan area, the Kanto region, where it causes mega-thrust earthquakes, such as the 1703 Genroku earthquake (M8.0) and the 1923 Kanto earthquake (M7.9) which had 105,000 fatalities. The vertical proximity of this down going lithospheric plate is of concern because the greater Tokyo urban region has a population of 42 million and is the center of approximately 40% of the nation's economic activities. A M7+ earthquake in this region at present has high potential to produce devastating loss of life and property with even greater global economic repercussions. The M7+ earthquake is evaluated to occur with a probability of 70% in 30 years by the Earthquake Research Committee of Japan. In 2002, a consortium of universities and government agencies in Japan started the Special Project for Earthquake Disaster Mitigation in Urban Areas, a project to improve information needed for seismic hazards analyses of the largest urban centers. Assessment in Kanto of the seismic hazard produced by the Philippine Sea Plate (PSP) mega-thrust earthquakes requires identification of all significant faults and possible earthquake scenarios and rupture behavior, regional characterizations of PSP geometry and the overlying Honshu arc physical properties (e.g., seismic wave velocities, densities, attenuation), and local near-surface seism ic site effects. Our study addresses (1) improved regional characterization of the PSP geometry based on new deep seismic reflection profiles (Sato etal.,2005), reprocessed off-shore profiles (Kimura et al.,2005), and a dense seismic array in the Boso peninsular (Hagiwara et al., 2006) and (2) identification of asperities of the mega-thrust at the top of the PSP. We qualitatively examine the relationship between seismic reflections and asperities inferred by reflection physical properties. We also discuss the relation between deformation of PSP and intra-slab M7+ earthquakes: the

  5. GPS Technologies as a Tool to Detect the Pre-Earthquake Signals Associated with Strong Earthquakes

    NASA Astrophysics Data System (ADS)

    Pulinets, S. A.; Krankowski, A.; Hernandez-Pajares, M.; Liu, J. Y. G.; Hattori, K.; Davidenko, D.; Ouzounov, D.

    2015-12-01

    The existence of ionospheric anomalies before earthquakes is now widely accepted. These phenomena started to be considered by GPS community to mitigate the GPS signal degradation over the territories of the earthquake preparation. The question is still open if they could be useful for seismology and for short-term earthquake forecast. More than decade of intensive studies proved that ionospheric anomalies registered before earthquakes are initiated by processes in the boundary layer of atmosphere over earthquake preparation zone and are induced in the ionosphere by electromagnetic coupling through the Global Electric Circuit. Multiparameter approach based on the Lithosphere-Atmosphere-Ionosphere Coupling model demonstrated that earthquake forecast is possible only if we consider the final stage of earthquake preparation in the multidimensional space where every dimension is one from many precursors in ensemble, and they are synergistically connected. We demonstrate approaches developed in different countries (Russia, Taiwan, Japan, Spain, and Poland) within the framework of the ISSI and ESA projects) to identify the ionospheric precursors. They are also useful to determine the all three parameters necessary for the earthquake forecast: impending earthquake epicenter position, expectation time and magnitude. These parameters are calculated using different technologies of GPS signal processing: time series, correlation, spectral analysis, ionospheric tomography, wave propagation, etc. Obtained results from different teams demonstrate the high level of statistical significance and physical justification what gives us reason to suggest these methodologies for practical validation.

  6. In vivo polymerization of poly(3,4-ethylenedioxythiophene) in the living rat hippocampus does not cause a significant loss of performance in a delayed alternation task

    NASA Astrophysics Data System (ADS)

    Ouyang, Liangqi; Shaw, Crystal L.; Kuo, Chin-chen; Griffin, Amy L.; Martin, David C.

    2014-04-01

    -polymerization time intervals, the polymerization did not cause significant deficits in performance of the DA task, suggesting that hippocampal function was not impaired by PEDOT deposition. However, GFAP+ and ED-1+ cells were also found at the deposition two weeks after the polymerization, suggesting potential secondary scarring. Therefore, less extensive deposition or milder deposition conditions may be desirable to minimize this scarring while maintaining decreased system impedance.

  7. In vivo polymerization of poly(3,4-ethylenedioxythiophene) (PEDOT) in living rat hippocampus does not cause a significant loss of performance in a delayed alternation (DA) task

    PubMed Central

    Ouyang, Liangqi; Shaw, Crystal L.; Kuo, Chin-chen; Griffin, Amy L.; Martin, David C.

    2014-01-01

    -polymerization time intervals, the polymerization did not cause significant deficits in performance of the DA task, suggesting that hippocampal function was not impaired by PEDOT deposition. However, GFAP+ and ED-1+ cells were also found at the deposition 2 weeks after the polymerization, suggesting potential secondary scarring. Therefore less extensive deposition or milder deposition conditions may be desirable to minimize this scarring while maintaining decreased system impedance. PMID:24503720

  8. Importance of weak minerals on earthquake mechanics

    NASA Astrophysics Data System (ADS)

    Kaneki, S.; Hirono, T.

    2017-12-01

    The role of weak minerals such as smectite and talc on earthquake mechanics is one of the important issues, and has been debated for recent several decades. Traditionally weak minerals in fault have been reported to weaken fault strength causing from its low frictional resistance. Furthermore, velocity-strengthening behavior of such weak mineral (talc) is considered to responsible for fault creep (aseismic slip) in the San Andreas fault. In contrast, recent studies reported that large amount of weak smectite in the Japan Trench could facilitate gigantic seismic slip during the 2011 Tohoku-oki earthquake. To investigate the role of weak minerals on rupture propagation process and magnitude of slip, we focus on the frictional properties of carbonaceous materials (CMs), which is the representative weak materials widely distributed in and around the convergent boundaries. Field observation and geochemical analyses revealed that graphitized CMs-layer is distributed along the slip surface of a fossil plate-subduction fault. Laboratory friction experiments demonstrated that pure quartz, bulk mixtures with bituminous coal (1 wt.%), and quartz with layered coal samples exhibited almost similar frictional properties (initial, yield, and dynamic friction). However, mixtures of quartz (99 wt.%) and layered graphite (1 wt.%) showed significantly lower initial and yield friction coefficient (0.31 and 0.50, respectively). Furthermore, the stress ratio S, defined as (yield stress-initial stress)/(initial stress-dynamic stress), increased in layered graphite samples (1.97) compared to quartz samples (0.14). Similar trend was observed in smectite-rich fault gouge. By referring the reported results of dynamic rupture propagation simulation using S ratio of 1.4 (typical value for the Japan Trench) and 2.0 (this study), we confirmed that higher S ratio results in smaller slip distance by approximately 20 %. On the basis of these results, we could conclude that weak minerals have lower

  9. Spatial and Temporal Variations in Earthquake Stress Drop on Gofar Transform Fault, East Pacific Rise: Implications for Fault Strength

    NASA Astrophysics Data System (ADS)

    Moyer, P. A.; Boettcher, M. S.; McGuire, J. J.; Collins, J. A.

    2017-12-01

    During the last five seismic cycles on Gofar transform fault on the East Pacific Rise, the largest earthquakes (6.0 ≤ Mw ≤ 6.2) have repeatedly ruptured the same fault segment (rupture asperity), while intervening fault segments host swarms of microearthquakes. Previous studies on Gofar have shown that these segments of low (≤10%) seismic coupling contain diffuse zones of seismicity and P-wave velocity reduction compared with the rupture asperity; suggesting heterogeneous fault properties control earthquake behavior. We investigate the role systematic differences in material properties have on earthquake rupture along Gofar using waveforms from ocean bottom seismometers that recorded the end of the 2008 Mw 6.0 seismic cycle.We determine stress drop for 117 earthquakes (2.4 ≤ Mw ≤ 4.2) that occurred in and between rupture asperities from corner frequency derived using an empirical Green's function spectral ratio method and seismic moment obtained by fitting the omega-square source model to the low frequency amplitude of earthquake spectra. We find stress drops from 0.03 to 2.7 MPa with significant spatial variation, including 2 times higher average stress drop in the rupture asperity compared to fault segments with low seismic coupling. We interpret an inverse correlation between stress drop and P-wave velocity reduction as the effect of damage on earthquake rupture. Earthquakes with higher stress drops occur in more intact crust of the rupture asperity, while earthquakes with lower stress drops occur in regions of low seismic coupling and reflect lower strength, highly fractured fault zone material. We also observe a temporal control on stress drop consistent with log-time healing following the Mw 6.0 mainshock, suggesting a decrease in stress drop as a result of fault zone damage caused by the large earthquake.

  10. Strong ground motion from the michoacan, Mexico, earthquake.

    PubMed

    Anderson, J G; Bodin, P; Brune, J N; Prince, J; Singh, S K; Quaas, R; Onate, M

    1986-09-05

    The network of strong motion accelerographs in Mexico includes instruments that were installed, under an international cooperative research program, in sites selected for the high potenial of a large earthquake. The 19 September 1985 earthquake (magnitude 8.1) occurred in a seismic gap where an earthquake was expected. As a result, there is an excellent descripton of the ground motions that caused the disaster.

  11. [Family function and depression in relatives of earthquake victims: a survey conducted one year after China's Wenchuan Earthquake].

    PubMed

    Hu, Xiao-Lin; Li, Xiao-Lin; Jiang, Xiao-Lian; Li, Rong; Dou, Xin-Man

    2012-10-01

    The Wenchuan Earthquake that hit Sichuan, China in 2008 not only caused huge losses in terms of human life and economic damage. It also caused psychological trauma in survivors, especially those who had lost relatives and close friends (bereaved). In the aftermath of earthquakes, bereaved individuals require family and spiritual renewal in addition to material assistance. This study investigated the status of and relationship between family function and depression in bereaved individuals living in areas devastated by the Wenchuan Earthquake. Results provide baseline information for post-disaster family reconstruction. This cross-sectional study surveyed 264 qualified bereaved individuals who lived in an area hard hit by the Wenchuan Earthquake. Face-to-face interviews were administered based on the family APGAR(adaptation, partnership, growth, affection, resolve) index and Hamilton depression (HAMD) scale. The mean family function score for participants was 6.52 ± 2.65. Results for half (50.0%) of participants indicated "good" family function. Results indicated marital status, family structure and status of having another baby as factors that significantly influence family function (p < .05). Participants' mean depression score was 40.41 ± 9.35, with all (100%) of participants demonstrating symptoms of depression. The 5 most prevalent depressive symptoms were: depressed mood, decreased interest in work, mental anxiety, diminished capacity and agitation. Results showed marital status, leisure frequency, economic status, and having another baby as factors that significantly influenced family function (p < .05). A Pearson's correlation analysis indicated no significant relationship between level of depression and family function (p >.05). Family functions of the bereaved living in areas hard hit by the Wenchuan Earthquake were all undermined to varying degrees. Although participants all exhibited depressive symptoms, this study found no affect of such symptoms on

  12. Investigation of atmospheric anomalies associated with Kashmir and Awaran Earthquakes

    NASA Astrophysics Data System (ADS)

    Mahmood, Irfan; Iqbal, Muhammad Farooq; Shahzad, Muhammad Imran; Qaiser, Saddam

    2017-02-01

    The earthquake precursors' anomalies at diverse elevation ranges over the seismogenic region and prior to the seismic events are perceived using Satellite Remote Sensing (SRS) techniques and reanalysis datasets. In the current research, seismic precursors are obtained by analyzing anomalies in Outgoing Longwave Radiation (OLR), Air Temperature (AT), and Relative Humidity (RH) before the two strong Mw>7 earthquakes in Pakistan occurred on 8th October 2005 in Azad Jammu Kashmir with Mw 7.6, and 24th September 2013 in Awaran, Balochistan with Mw 7.7. Multi-parameter data were computed based on multi-year background data for anomalies computation. Results indicate significant transient variations in observed parameters before the main event. Detailed analysis suggests presence of pre-seismic activities one to three weeks prior to the main earthquake event that vanishes after the event. These anomalies are due to increase in temperature after release of gases and physical and chemical interactions on earth surface before the earthquake. The parameter variations behavior for both Kashmir and Awaran earthquake events are similar to other earthquakes in different regions of the world. This study suggests that energy release is not concentrated to a single fault but instead is released along the fault zone. The influence of earthquake events on lightning were also investigated and it was concluded that there is a significant atmospheric lightning activity after the earthquake suggesting a strong possibility for an earthquake induced thunderstorm. This study is valuable for identifying earthquake precursors especially in earthquake prone areas.

  13. Numerical Simulation of Strong Ground Motion at Mexico City:A Hybrid Approach for Efficient Evaluation of Site Amplification and Path Effects for Different Types of Earthquakes

    NASA Astrophysics Data System (ADS)

    Cruz, H.; Furumura, T.; Chavez-Garcia, F. J.

    2002-12-01

    The estimation of scenarios of the strong ground motions caused by future great earthquakes is an important problem in strong motion seismology. This was pointed out by the great 1985 Michoacan earthquake, which caused a great damage in Mexico City, 300 km away from the epicenter. Since the seismic wavefield is characterized by the source, path and site effects, the pattern of strong motion damage from different types of earthquakes should differ significantly. In this study, the scenarios for intermediate-depth normal-faulting, shallow-interplate thrust faulting, and crustal earthquakes have been estimated using a hybrid simulation technique. The character of the seismic wavefield propagating from the source to Mexico City for each earthquake was first calculated using the pseudospectral method for 2D SH waves. The site amplifications in the shallow structure of Mexico City are then calculated using the multiple SH wave reverberation theory. The scenarios of maximum ground motion for both inslab and interplate earthquakes obtained by the simulation show a good agreement with the observations. This indicates the effectiveness of the hybrid simulation approach to investigate the strong motion damage for future earthquakes.

  14. Prototype operational earthquake prediction system

    USGS Publications Warehouse

    Spall, Henry

    1986-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2011-12-01

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

  16. Earthquakes, fluid pressures and rapid subduction zone metamorphism

    NASA Astrophysics Data System (ADS)

    Viete, D. R.

    2013-12-01

    High-pressure/low-temperature (HP/LT) metamorphism is commonly incomplete, meaning that large tracts of rock can remain metastable at blueschist- and eclogite-facies conditions for timescales up to millions of years [1]. When HP/LT metamorphism does take place, it can occur over extremely short durations (<<1 Myr) [1-2]. HP/LT metamorphism must be associated with processes that allow large volumes of rock to remain unaffected over long periods of time, but then suddenly undergo localized metamorphism. Existing models for HP/LT metamorphism have focussed on the role of fluids in providing heat for metamorphism [2] or catalyzing metamorphic reactions [1]. Earthquakes in subduction zone settings can occur to depths of 100s of km. Metamorphic dehydration and the associated development of elevated pore pressures in HP/LT metamorphic rocks has been identified as a cause of earthquake activity at such great depths [3-4]. The process of fracturing/faulting significantly increases rock permeability, causing channelized fluid flow and dissipation of pore pressures [3-4]. Thus, deep subduction zone earthquakes are thought to reflect an evolution in fluid pressure, involving: (1) an initial increase in pore pressure by heating-related dehydration of subduction zone rocks, and (2) rapid relief of pore pressures by faulting and channelized flow. Models for earthquakes at depth in subduction zones have focussed on the in situ effects of dehydration and then sudden escape of fluids from the rock mass following fracturing [3-4]. On the other hand, existing models for rapid and incomplete metamorphism in subduction zones have focussed only on the effects of heating and/or hydration with the arrival of external fluids [1-2]. Significant changes in pressure over very short timescales should result in rapid mineral growth and/or disequilibrium texture development in response to overstepping of mineral reaction boundaries. The repeated process of dehydration-pore pressure development-earthquake

  17. New earthquake catalog reexamines Hawaii's seismic history

    USGS Publications Warehouse

    Wright, Thomas L.; Klein, Fred W.

    2000-01-01

    On April 2,1868, an earthquake of magnitude 7.9 occurred beneath the southern part of the island of Hawaii. The quake, which was felt throughout all of the Hawaiian Islands, had a Modified Mercalli (MM) intensity of XII near its source.The destruction caused by a quake that large is nearly complete. A landslide triggered by the quake buried a small village, killing 31 people, and a tsunami that swept over coastal settlements added to the death toll. We know as much as we do about this and other early earthquakes thanks to detailed records kept by Hawaiian missionaries, including the remarkable diary maintained by the Lyman family that documented every earthquake felt at their home in Hilo between 1833 and 1917 [Wyss et al., 1992].Our analysis of these and other historical records indicates that Hawaii was at least as intensely seismic in the 19th century and first half of the 20th century as in its more recent past, with 26 M ≥6.0 earthquakes occurring from 1823 to 1903 and 20 M ≥6.0 earthquakes from 1904 to 1959. Just five M ≥6.0 earthquakes occurred from 1960 to 1999. The potential damage caused by a repeat of some of the larger historic events could be catastrophic today.

  18. The aftershock signature of supershear earthquakes.

    PubMed

    Bouchon, Michel; Karabulut, Hayrullah

    2008-06-06

    Recent studies show that earthquake faults may rupture at speeds exceeding the shear wave velocity of rocks. This supershear rupture produces in the ground a seismic shock wave similar to the sonic boom produced by a supersonic airplane. This shock wave may increase the destruction caused by the earthquake. We report that supershear earthquakes are characterized by a specific pattern of aftershocks: The fault plane itself is remarkably quiet whereas aftershocks cluster off the fault, on secondary structures that are activated by the supershear rupture. The post-earthquake quiescence of the fault shows that friction is relatively uniform over supershear segments, whereas the activation of off-fault structures is explained by the shock wave radiation, which produces high stresses over a wide zone surrounding the fault.

  19. Sea-level changes before large earthquakes

    USGS Publications Warehouse

    Wyss, M.

    1978-01-01

    Changes in sea level have long been used as a measure of local uplift and subsidence associated with large earthquakes. For instance, in 1835, the British naturalist Charles Darwin observed that sea level dropped by 2.7 meters during the large earthquake in Concepcion, CHile. From this piece of evidence and the terraces along the beach that he saw, Darwin concluded that the Andes had grown to their present height through earthquakes. Much more recently, George Plafker and James C. Savage of the U.S Geological Survey have shown, from barnacle lines, that the great 1960 Chile and the 1964 Alaska earthquakes caused several meters of vertical displacement of the shoreline. 

  20. Chapter F. The Loma Prieta, California, Earthquake of October 17, 1989 - Marina District

    USGS Publications Warehouse

    O'Rourke, Thomas D.

    1992-01-01

    During the earthquake, a total land area of about 4,300 km2 was shaken with seismic intensities that can cause significant damage to structures. The area of the Marina District of San Francisco is only 4.0 km2--less than 0.1 percent of the area most strongly affected by the earthquake--but its significance with respect to engineering, seismology, and planning far outstrips its proportion of shaken terrain and makes it a centerpiece for lessons learned from the earthquake. The Marina District provides perhaps the most comprehensive case history of seismic effects at a specific site developed for any earthquake. The reports assembled in this chapter, which provide an account of these seismic effects, constitute a unique collection of studies on site, as well as infrastructure and societal, response that cover virtually all aspects of the earthquake, ranging from incoming ground waves to the outgoing airwaves used for emergency communication. The Marina District encompasses the area bounded by San Francisco Bay on the north, the Presidio on the west, and Lombard Street and Van Ness Avenue on the south and east, respectively. Nearly all of the earthquake damage in the Marina District, however, occurred within a considerably smaller area of about 0.75 km2, bounded by San Francisco Bay and Baker, Chestnut, and Buchanan Streets. At least five major aspects of earthquake response in the Marina District are covered by the reports in this chapter: (1) dynamic site response, (2) soil liquefaction, (3) lifeline performance, (4) building performance, and (5) emergency services.

  1. 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.

  2. Fragmentation of wall rock garnets during deep crustal earthquakes

    PubMed Central

    Austrheim, Håkon; Dunkel, Kristina G.; Plümper, Oliver; Ildefonse, Benoit; Liu, Yang; Jamtveit, Bjørn

    2017-01-01

    Fractures and faults riddle the Earth’s crust on all scales, and the deformation associated with them is presumed to have had significant effects on its petrological and structural evolution. However, despite the abundance of directly observable earthquake activity, unequivocal evidence for seismic slip rates along ancient faults is rare and usually related to frictional melting and the formation of pseudotachylites. We report novel microstructures from garnet crystals in the immediate vicinity of seismic slip planes that transected lower crustal granulites during intermediate-depth earthquakes in the Bergen Arcs area, western Norway, some 420 million years ago. Seismic loading caused massive dislocation formations and fragmentation of wall rock garnets. Microfracturing and the injection of sulfide melts occurred during an early stage of loading. Subsequent dilation caused pervasive transport of fluids into the garnets along a network of microfractures, dislocations, and subgrain and grain boundaries, leading to the growth of abundant mineral inclusions inside the fragmented garnets. Recrystallization by grain boundary migration closed most of the pores and fractures generated by the seismic event. This wall rock alteration represents the initial stages of an earthquake-triggered metamorphic transformation process that ultimately led to reworking of the lower crust on a regional scale. PMID:28261660

  3. Possible seasonality in large deep-focus earthquakes

    NASA Astrophysics Data System (ADS)

    Zhan, Zhongwen; Shearer, Peter M.

    2015-09-01

    Large deep-focus earthquakes (magnitude > 7.0, depth > 500 km) have exhibited strong seasonality in their occurrence times since the beginning of global earthquake catalogs. Of 60 such events from 1900 to the present, 42 have occurred in the middle half of each year. The seasonality appears strongest in the northwest Pacific subduction zones and weakest in the Tonga region. Taken at face value, the surplus of northern hemisphere summer events is statistically significant, but due to the ex post facto hypothesis testing, the absence of seasonality in smaller deep earthquakes, and the lack of a known physical triggering mechanism, we cannot rule out that the observed seasonality is just random chance. However, we can make a testable prediction of seasonality in future large deep-focus earthquakes, which, given likely earthquake occurrence rates, should be verified or falsified within a few decades. If confirmed, deep earthquake seasonality would challenge our current understanding of deep earthquakes.

  4. Identifying slow-moving landslides using LiDAR DEM and SAR interferometry: An Example of 2006 Meinong Earthquake

    NASA Astrophysics Data System (ADS)

    Chen, R. F.; Lin, C. W.; Hsu, Y. J.; Zhang, L.; Liang, H. Y.

    2017-12-01

    The February 6 Meinong Earthquake of 2016 (ML=6.4; at 23.85ºN, 120.81ºE), with a focal depth of 16.7 km, was triggered by an unknown blind thrust in southern Taiwan. The earthquake not only induced coseismic crustal deformation, but also triggered slow-moving landslides nearby the Longchuan active fault. In this study, high-resolution LiDAR derived DEM of 2010 is used to recognize locations of previous slow-moving landslides according to their topographic signatures, such as main escarpment, trench, double ridge, and crown cracks. Within an area of 4.5 km x 1.8 km along Longchuan fault near the ridge of Longchuan mountain, over 50 sites with landslide signatures are recognized, and three of them are over 10 ha. These earthquake-induced landslide deformations are detected from InSAR (synthetic aperture radar interferometry) images using Advanced Land Observing Satellite ALOS2/Phased-array L band and Sentinel 1 C-band SAR (PALSAR) data taken before and after the earthquake; some significant landslide deformation are even overlapped with areas where previous slow moving landslides were identified on the LiDAR DEM. Additionally, field investigation right after the earthquake in the study area also support that these previously identified landslides reactivated in the earthquake. Although these landslides do not cause serious damage due to their minor displacement in the Meinong Earthquake, the study results prove that LiDAR DEM is a powerful tool to identify and continuously monitor slow-motion landslides for preventing catastrophic failures that may be caused by hazardous earthquake or heavy rainfall.

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

    SciTech Connect

    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

  6. Future WGCEP Models and the Need for Earthquake Simulators

    NASA Astrophysics Data System (ADS)

    Field, E. H.

    2008-12-01

    The 2008 Working Group on California Earthquake Probabilities (WGCEP) recently released the Uniform California Earthquake Rupture Forecast version 2 (UCERF 2), developed jointly by the USGS, CGS, and SCEC with significant support from the California Earthquake Authority. Although this model embodies several significant improvements over previous WGCEPs, the following are some of the significant shortcomings that we hope to resolve in a future UCERF3: 1) assumptions of fault segmentation and the lack of fault-to-fault ruptures; 2) the lack of an internally consistent methodology for computing time-dependent, elastic-rebound-motivated renewal probabilities; 3) the lack of earthquake clustering/triggering effects; and 4) unwarranted model complexity. It is believed by some that physics-based earthquake simulators will be key to resolving these issues, either as exploratory tools to help guide the present statistical approaches, or as a means to forecast earthquakes directly (although significant challenges remain with respect to the latter).

  7. 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

  8. 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

  9. Using Smartphones to Detect Earthquakes

    NASA Astrophysics Data System (ADS)

    Kong, Q.; Allen, R. M.

    2012-12-01

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

  10. Frog Swarms: Earthquake Precursors or False Alarms?

    PubMed Central

    Grant, Rachel A.; Conlan, Hilary

    2013-01-01

    Simple Summary Media reports linking unusual animal behaviour with earthquakes can potentially create false alarms and unnecessary anxiety among people that live in earthquake risk zones. Recently large frog swarms in China and elsewhere have been reported as earthquake precursors in the media. By examining international media reports of frog swarms since 1850 in comparison to earthquake data, it was concluded that frog swarms are naturally occurring dispersal behaviour of juveniles and are not associated with earthquakes. However, the media in seismic risk areas may be more likely to report frog swarms, and more likely to disseminate reports on frog swarms after earthquakes have occurred, leading to an apparent link between frog swarms and earthquakes. Abstract In short-term earthquake risk forecasting, the avoidance of false alarms is of utmost importance to preclude the possibility of unnecessary panic among populations in seismic hazard areas. Unusual animal behaviour prior to earthquakes has been reported for millennia but has rarely been scientifically documented. Recently large migrations or unusual behaviour of amphibians have been linked to large earthquakes, and media reports of large frog and toad migrations in areas of high seismic risk such as Greece and China have led to fears of a subsequent large earthquake. However, at certain times of year large migrations are part of the normal behavioural repertoire of amphibians. News reports of “frog swarms” from 1850 to the present day were examined for evidence that this behaviour is a precursor to large earthquakes. It was found that only two of 28 reported frog swarms preceded large earthquakes (Sichuan province, China in 2008 and 2010). All of the reported mass migrations of amphibians occurred in late spring, summer and autumn and appeared to relate to small juvenile anurans (frogs and toads). It was concluded that most reported “frog swarms” are actually normal behaviour, probably caused by

  11. Earthquakes in Alaska

    USGS Publications Warehouse

    Haeussler, Peter J.; Plafker, George

    1995-01-01

    Earthquake risk is high in much of the southern half of Alaska, but it is not the same everywhere. This map shows the overall geologic setting in Alaska that produces earthquakes. The Pacific plate (darker blue) is sliding northwestward past southeastern Alaska and then dives beneath the North American plate (light blue, green, and brown) in southern Alaska, the Alaska Peninsula, and the Aleutian Islands. Most earthquakes are produced where these two plates come into contact and slide past each other. Major earthquakes also occur throughout much of interior Alaska as a result of collision of a piece of crust with the southern margin.

  12. Hiding earthquakes from scrupulous monitoring eyes of dense local seismic networks

    NASA Astrophysics Data System (ADS)

    Bogiatzis, P.; Ishii, M.; Kiser, E.

    2012-12-01

    Accurate and complete cataloguing of aftershocks is essential for a variety of purposes, including the estimation of the mainshock rupture area, the identification of seismic gaps, and seismic hazard assessment. However, immediately following large earthquakes, the seismograms recorded by local networks are noisy, with energy arriving from hundreds of aftershocks, in addition to different seismic phases interfering with one another. This causes deterioration in the performance of detection and location of earthquakes using conventional methods such as the S-P approach. This is demonstrated by results of back-projection analysis of teleseismic data showing that a significant number of events are undetected by the Japan Meteorological Agency, within the first twenty-four hours after the Mw9.0 Tohoku-oki, Japan earthquake. The spatial distribution of the hidden events is not arbitrary. Most of these earthquakes are located close to the trench, while some are located at the outer rise. Furthermore, there is a relatively sharp trench-parallel boundary separating the detected and undetected events. We investigate the cause of these hidden earthquakes using forward modeling. The calculation of raypaths for various source locations and takeoff angles with the "shooting" method suggests that this phenomenon is a consequence of the complexities associated with subducting slab. Laterally varying velocity structure defocuses the seismic energy from shallow earthquakes located near the trench and makes the observation of P and S arrivals difficult at stations situated on mainland Japan. Full waveform simulations confirm these results. Our forward calculations also show that the probability of detection is sensitive to the depth of the event. Shallower events near the trench are more difficult to detect than deeper earthquakes that are located inside the subducting plate for which the shadow-zone effect diminishes. The modeling effort is expanded to include three

  13. 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.

  14. Surface rupture and slip variation induced by the 2010 El Mayor-Cucapah earthquake, Baja California, quantified using COSI-Corr analysis on pre- and post-earthquake LiDAR acquisitions

    NASA Astrophysics Data System (ADS)

    Leprince, S.; Hudnut, K. W.; Akciz, S. O.; Hinojosa-Corona, A.; Fletcher, J. M.

    2011-12-01

    One-hundred and three years after the publication of the Lawson report on the Great 1906 earthquake, accurate documentation of surface deformation along the entire length of an earthquake is still challenging. Analysis of pre- and post-earthquake topographic data provides an opportunity to deliver the full 3D displacement field of the ground's surface. However, direct differencing of a pre- and post-earthquake digital topography model (DEM) generally leads to biased estimation of the vertical component of the deformation. Indeed, if the earthquake also produced significant horizontal motion, or if the pre- and post-earthquake DEM acquisitions exhibit non-negligible horizontal mis-registration, then the vertical offset measured by direct differencing will be biased by the local topography gradient. To overcome this limitation, we use the COSI-Corr sub-pixel correlation algorithm to estimate the relative horizontal offset between the pre- and post- 2010 El Mayor - Cucapah earthquake high resolution LiDAR acquisitions. Compensating for the horizontal offset between the two LiDAR acquisitions allows us to estimate unbiased measurements of the vertical component of the surface fault rupture induced by the El Mayor-Cucapah earthquake. We will also show the limitations of the available data set, such as aircraft jitter artifacts, which impaired accurate measurements of the horizontal component of the surface deformation. This analysis shows an unprecedented view of the complete vertical slip component of the rupture induced by the Mw 7.2 2010 El Mayor-Cucapah earthquake, sampled at every 5 m, over a length of about 100 km, and with a vertical accuracy of a few centimeters. Using sampling bins as narrow as 150 m and 1.5 km long, variations in the vertical component of an oblique slip earthquake are presented, with breaks along multiple fault-strands showing opposite dip directions and diffuse boundaries. With the availability of high precision pre- and post-earthquake data

  15. High Attenuation Rate for Shallow, Small Earthquakes in Japan

    NASA Astrophysics Data System (ADS)

    Si, Hongjun; Koketsu, Kazuki; Miyake, Hiroe

    2017-09-01

    We compared the attenuation characteristics of peak ground accelerations (PGAs) and velocities (PGVs) of strong motion from shallow, small earthquakes that occurred in Japan with those predicted by the equations of Si and Midorikawa (J Struct Constr Eng 523:63-70, 1999). The observed PGAs and PGVs at stations far from the seismic source decayed more rapidly than the predicted ones. The same tendencies have been reported for deep, moderate, and large earthquakes, but not for shallow, moderate, and large earthquakes. This indicates that the peak values of ground motion from shallow, small earthquakes attenuate more steeply than those from shallow, moderate or large earthquakes. To investigate the reason for this difference, we numerically simulated strong ground motion for point sources of M w 4 and 6 earthquakes using a 2D finite difference method. The analyses of the synthetic waveforms suggested that the above differences are caused by surface waves, which are predominant at stations far from the seismic source for shallow, moderate earthquakes but not for shallow, small earthquakes. Thus, although loss due to reflection at the boundaries of the discontinuous Earth structure occurs in all shallow earthquakes, the apparent attenuation rate for a moderate or large earthquake is essentially the same as that of body waves propagating in a homogeneous medium due to the dominance of surface waves.

  16. Biological Indicators in Studies of Earthquake Precursors

    NASA Astrophysics Data System (ADS)

    Sidorin, A. Ya.; Deshcherevskii, A. V.

    2012-04-01

    Time series of data on variations in the electric activity (EA) of four species of weakly electric fish Gnathonemus leopoldianus and moving activity (MA) of two cat-fishes Hoplosternum thoracatum and two groups of Columbian cockroaches Blaberus craniifer were analyzed. The observations were carried out in the Garm region of Tajikistan within the frameworks of the experiments aimed at searching for earthquake precursors. An automatic recording system continuously recorded EA and DA over a period of several years. Hourly means EA and MA values were processed. Approximately 100 different parameters were calculated on the basis of six initial EA and MA time series, which characterize different variations in the EA and DA structure: amplitude of the signal and fluctuations of activity, parameters of diurnal rhythms, correlated changes in the activity of various biological indicators, and others. A detailed analysis of the statistical structure of the total array of parametric time series obtained in the experiment showed that the behavior of all animals shows a strong temporal variability. All calculated parameters are unstable and subject to frequent changes. A comparison of the data obtained with seismicity allow us to make the following conclusions: (1) The structure of variations in the studied parameters is represented by flicker noise or even a more complex process with permanent changes in its characteristics. Significant statistics are required to prove the cause-and-effect relationship of the specific features of such time series with seismicity. (2) The calculation of the reconstruction statistics in the EA and MA series structure demonstrated an increase in their frequency in the last hours or a few days before the earthquake if the hypocenter distance is comparable to the source size. Sufficiently dramatic anomalies in the behavior of catfishes and cockroaches (changes in the amplitude of activity variation, distortions of diurnal rhythms, increase in the

  17. Long-period building response to earthquakes in the San Francisco Bay Area

    USGS Publications Warehouse

    Olsen, A.H.; Aagaard, Brad T.; Heaton, T.H.

    2008-01-01

    This article reports a study of modeled, long-period building responses to ground-motion simulations of earthquakes in the San Francisco Bay Area. The earthquakes include the 1989 magnitude 6.9 Loma Prieta earthquake, a magnitude 7.8 simulation of the 1906 San Francisco earthquake, and two hypothetical magnitude 7.8 northern San Andreas fault earthquakes with hypocenters north and south of San Francisco. We use the simulated ground motions to excite nonlinear models of 20-story, steel, welded moment-resisting frame (MRF) buildings. We consider MRF buildings designed with two different strengths and modeled with either ductile or brittle welds. Using peak interstory drift ratio (IDR) as a performance measure, the stiffer, higher strength building models outperform the equivalent more flexible, lower strength designs. The hypothetical magnitude 7.8 earthquake with hypocenter north of San Francisco produces the most severe ground motions. In this simulation, the responses of the more flexible, lower strength building model with brittle welds exceed an IDR of 2.5% (that is, threaten life safety) on 54% of the urban area, compared to 4.6% of the urban area for the stiffer, higher strength building with ductile welds. We also use the simulated ground motions to predict the maximum isolator displacement of base-isolated buildings with linear, single-degree-of-freedom (SDOF) models. For two existing 3-sec isolator systems near San Francisco, the design maximum displacement is 0.5 m, and our simulations predict isolator displacements for this type of system in excess of 0.5 m in many urban areas. This article demonstrates that a large, 1906-like earthquake could cause significant damage to long-period buildings in the San Francisco Bay Area.

  18. Psychological distress among Bam earthquake survivors in Iran: a population-based study.

    PubMed

    Montazeri, Ali; Baradaran, Hamid; Omidvari, Sepideh; Azin, Seyed Ali; Ebadi, Mehdi; Garmaroudi, Gholamreza; Harirchi, Amir Mahmood; Shariati, Mohammad

    2005-01-11

    An earthquake measuring 6.3 on the Richter scale struck the city of Bam in Iran on the 26th of December 2003 at 5.26 A.M. It was devastating, and left over 40,000 dead and around 30,000 injured. The profound tragedy of thousands killed has caused emotional and psychological trauma for tens of thousands of people who have survived. A study was carried out to assess psychological distress among Bam earthquake survivors and factors associated with severe mental health in those who survived the tragedy. This was a population-based study measuring psychological distress among the survivors of Bam earthquake in Iran. Using a multi-stage stratified sampling method a random sample of individuals aged 15 years and over living in Bam were interviewed. Psychological distress was measured using the 12-item General Health Questionnaire (GHQ-12). In all 916 survivors were interviewed. The mean age of the respondents was 32.9 years (SD = 12.4), mostly were males (53%), married (66%) and had secondary school education (50%). Forty-one percent reported they lost 3 to 5 members of their family in the earthquake. In addition the findings showed that 58% of the respondents suffered from severe mental health as measured by the GHQ-12 and this was three times higher than reported psychological distress among the general population. There were significant differences between sub-groups of the study sample with regard to their psychological distress. The results of the logistic regression analysis also indicated that female gender; lower education, unemployment, and loss of family members were associated with severe psychological distress among earthquake victims. The study findings indicated that the amount of psychological distress among earthquake survivors was high and there is an urgent need to deliver mental health care to disaster victims in local medical settings and to reduce negative health impacts of the earthquake adequate psychological counseling is needed for those who

  19. The January 2006 Volcanic-Tectonic Earthquake Swarm at Mount Martin, Alaska

    USGS Publications Warehouse

    Dixon, James P.; Power, John A.

    2009-01-01

    On January 8, 2006, a swarm of volcanic-tectonic earthquakes began beneath Mount Martin at the southern end of the Katmai volcanic cluster. This was the first recorded swarm at Mount Martin since continuous seismic monitoring began in 1996. The number of located earthquakes increased during the next four days, reaching a peak on January 11. For the next two days, the seismic activity decreased, and on January 14, the number of events increased to twice the previous day's total. Following this increase in activity, seismicity declined, returning to background levels by the end of the month. The Alaska Volcano Observatory located 860 earthquakes near Mount Martin during January 2006. No additional signs of volcanic unrest were noted in association with this earthquake swarm. The earthquakes in the Mount Martin swarm, relocated using the double difference technique, formed an elongated cluster dipping to the southwest. Focal mechanisms beneath Mount Martin show a mix of normal, thrust, and strike-slip solutions, with normal focal mechanisms dominating. For earthquakes more than 1 km from Mount Martin, all focal mechanisms showed normal faulting. The calculated b-value for the Mount Martin swarm is 0.98 and showed no significant change before, during, or after the swarm. The triggering mechanism for the Mount Martin swarm is unknown. The time-history of earthquake occurrence is indicative of a volcanic cause; however, there were no low-frequency events or observations, such as increased steaming associated with the swarm. During the swarm, there was no change in the b-value, and the distribution and type of focal mechanisms were similar to those in the period before the anomalous activity. The short duration of the swarm, the similarity in observed focal mechanisms, and the lack of additional signs of unrest suggest this swarm did not result from a large influx of magma within the shallow crust beneath Mount Martin.

  20. 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...

  1. 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...

  2. One year after twin earthquakes in Northwest Iran.

    PubMed

    Babaei-Ghazani, Arash; Eftekhar Sadat, Bina

    2014-03-01

    Every year in most earthquakes more than thousands of lives are lost, mainly in middle- and low-income countries. Disability and rehabilitation in third world countries could cause disastrous negative effect in living expense of families. So many preventable disabilities are result of these earthquakes and we hope reminding it will make a difference.

  3. Earthquake precursors: activation or quiescence?

    NASA Astrophysics Data System (ADS)

    Rundle, John B.; Holliday, James R.; Yoder, Mark; Sachs, Michael K.; Donnellan, Andrea; Turcotte, Donald L.; Tiampo, Kristy F.; Klein, William; Kellogg, Louise H.

    2011-10-01

    We discuss the long-standing question of whether the probability for large earthquake occurrence (magnitudes m > 6.0) is highest during time periods of smaller event activation, or highest during time periods of smaller event quiescence. The physics of the activation model are based on an idea from the theory of nucleation, that a small magnitude earthquake has a finite probability of growing into a large earthquake. The physics of the quiescence model is based on the idea that the occurrence of smaller earthquakes (here considered as magnitudes m > 3.5) may be due to a mechanism such as critical slowing down, in which fluctuations in systems with long-range interactions tend to be suppressed prior to large nucleation events. To illuminate this question, we construct two end-member forecast models illustrating, respectively, activation and quiescence. The activation model assumes only that activation can occur, either via aftershock nucleation or triggering, but expresses no choice as to which mechanism is preferred. Both of these models are in fact a means of filtering the seismicity time-series to compute probabilities. Using 25 yr of data from the California-Nevada catalogue of earthquakes, we show that of the two models, activation and quiescence, the latter appears to be the better model, as judged by backtesting (by a slight but not significant margin). We then examine simulation data from a topologically realistic earthquake model for California seismicity, Virtual California. This model includes not only earthquakes produced from increases in stress on the fault system, but also background and off-fault seismicity produced by a BASS-ETAS driving mechanism. Applying the activation and quiescence forecast models to the simulated data, we come to the opposite conclusion. Here, the activation forecast model is preferred to the quiescence model, presumably due to the fact that the BASS component of the model is essentially a model for activated seismicity. These

  4. Magnitude and intensity: Measures of earthquake size and severity

    USGS Publications Warehouse

    Spall, Henry

    1982-01-01

    Earthquakes can be measured in terms of either the amount of energy they release (magnitude) or the degree of ground shaking they cause at a particular locality (intensity).  Although magnitude and intensity are basically different measures of an earthquake, they are frequently confused by the public and new reports of earthquakes.  Part of the confusion probably arises from the general similarity of scales used express these quantities.  The various magnitude scales represent logarithmic expressions of the energy released by an earthquake.  Magnitude is calculated from the record made by an earthquake on a calibrated seismograph.  There are no upper or lower limits to magnitude, although no measured earthquakes have exceeded magnitude 8.9.

  5. Modelling the elements of country vulnerability to earthquake disasters.

    PubMed

    Asef, M R

    2008-09-01

    Earthquakes have probably been the most deadly form of natural disaster in the past century. Diversity of earthquake specifications in terms of magnitude, intensity and frequency at the semicontinental scale has initiated various kinds of disasters at a regional scale. Additionally, diverse characteristics of countries in terms of population size, disaster preparedness, economic strength and building construction development often causes an earthquake of a certain characteristic to have different impacts on the affected region. This research focuses on the appropriate criteria for identifying the severity of major earthquake disasters based on some key observed symptoms. Accordingly, the article presents a methodology for identification and relative quantification of severity of earthquake disasters. This has led to an earthquake disaster vulnerability model at the country scale. Data analysis based on this model suggested a quantitative, comparative and meaningful interpretation of the vulnerability of concerned countries, and successfully explained which countries are more vulnerable to major disasters.

  6. Protecting Your Family From Earthquakes-The Seven Steps to Earthquake Safety (in Spanish and English)

    USGS Publications Warehouse

    Developed by American Red Cross, Asian Pacific Fund

    2007-01-01

    This book is provided here to share an important message on emergency preparedness. Historically, we have suffered earthquakes here in the San Francisco Bay Area that have caused severe hardship for residents and incredible damage to our cities. It is likely we will experience a severe earthquake within the next 30 years. Many of us come from other countries where we have experienced earth- quakes, so we believe that we understand them. However, the way we prepare for earthquakes in our home country may be different from the way it is necessary to prepare for earthquakes here. Very f w people die from collapsing buildings in the Bay Area because most structures are built to stand up to the shaking. But it is quite possible that your family will be without medical care or grocery stores and separated from one another for several days to weeks. It will ultimately be up to you to keep your family safe until help arrives, so we are asking you to join us in learning to take care of your family before, during, and after an earthquake. The first step is to read this book. Everyone in your family, children and adults, can learn how to prepare for an earthquake. Then take advantage of the American Red Cross Earthquake Preparedness training courses offered in your community. These preparedness courses are free, and also offered in Spanish and available to everyone in the community regardless of family history, leg al status, gender, or age. We encourage you to take one of these free training workshops. Look on the back cover for more information. Remember that an earthquake can occur without warning, and the only way that we can reduce the harm caused by earthquakes is to be prepared. Get Prepared!

  7. Statistical tests of simple earthquake cycle models

    USGS Publications Warehouse

    Devries, Phoebe M. R.; Evans, Eileen

    2016-01-01

    A central goal of observing and modeling the earthquake cycle is to forecast when a particular fault may generate an earthquake: a fault late in its earthquake cycle may be more likely to generate an earthquake than a fault early in its earthquake cycle. Models that can explain geodetic observations throughout the entire earthquake cycle may be required to gain a more complete understanding of relevant physics and phenomenology. Previous efforts to develop unified earthquake models for strike-slip faults have largely focused on explaining both preseismic and postseismic geodetic observations available across a few faults in California, Turkey, and Tibet. An alternative approach leverages the global distribution of geodetic and geologic slip rate estimates on strike-slip faults worldwide. Here we use the Kolmogorov-Smirnov test for similarity of distributions to infer, in a statistically rigorous manner, viscoelastic earthquake cycle models that are inconsistent with 15 sets of observations across major strike-slip faults. We reject a large subset of two-layer models incorporating Burgers rheologies at a significance level of α = 0.05 (those with long-term Maxwell viscosities ηM <~ 4.0 × 1019 Pa s and ηM >~ 4.6 × 1020 Pa s) but cannot reject models on the basis of transient Kelvin viscosity ηK. Finally, we examine the implications of these results for the predicted earthquake cycle timing of the 15 faults considered and compare these predictions to the geologic and historical record.

  8. Universal Recurrence Time Statistics of Characteristic Earthquakes

    NASA Astrophysics Data System (ADS)

    Goltz, C.; Turcotte, D. L.; Abaimov, S.; Nadeau, R. M.

    2006-12-01

    Characteristic earthquakes are defined to occur quasi-periodically on major faults. Do recurrence time statistics of such earthquakes follow a particular statistical distribution? If so, which one? The answer is fundamental and has important implications for hazard assessment. The problem cannot be solved by comparing the goodness of statistical fits as the available sequences are too short. The Parkfield sequence of M ≍ 6 earthquakes, one of the most extensive reliable data sets available, has grown to merely seven events with the last earthquake in 2004, for example. Recently, however, advances in seismological monitoring and improved processing methods have unveiled so-called micro-repeaters, micro-earthquakes which recur exactly in the same location on a fault. It seems plausible to regard these earthquakes as a miniature version of the classic characteristic earthquakes. Micro-repeaters are much more frequent than major earthquakes, leading to longer sequences for analysis. Due to their recent discovery, however, available sequences contain less than 20 events at present. In this paper we present results for the analysis of recurrence times for several micro-repeater sequences from Parkfield and adjacent regions. To improve the statistical significance of our findings, we combine several sequences into one by rescaling the individual sets by their respective mean recurrence intervals and Weibull exponents. This novel approach of rescaled combination yields the most extensive data set possible. We find that the resulting statistics can be fitted well by an exponential distribution, confirming the universal applicability of the Weibull distribution to characteristic earthquakes. A similar result is obtained from rescaled combination, however, with regard to the lognormal distribution.

  9. Communication between earthquake clusters separated by over 30 km supports simple volcano plumbing

    NASA Astrophysics Data System (ADS)

    Jonsdottir, K.; Jonasson, K.; Gudmundsson, M. T.; Hensch, M.; Hooper, A. J.; Holohan, E. P.; Sigmundsson, F.; Halldorsson, S. A.; Hognadottir, T.; Magnússon, E.; Pálsson, F.; Walter, T. R.; Ofeigsson, B.; Parks, M.; Roberts, M. J.; Hjorleifsdottir, V.; Cesca, S.; Guðmundsson, G.; Hreinsdottir, S.; Jarosch, A. H.; Dumont, S.; Fridriksdóttir, H. M.; Barsotti, S.; Einarsson, P.

    2015-12-01

    The subglacial Bárðarbunga volcano is composed of a large oval caldera (7x11 km) and fissures extending tens of kilometers away from the caldera along the rift zone, which marks the divergent plate boundary across Iceland. On August 16th, 2014 an intense seismic swarm started below the Bárðarbunga caldera and in the two weeks that followed a dyke migrated some 47 km laterally in the uppermost 6-10 km of the crust along the rift. The dyke propagation terminated in lava fields just north of Vatnajökull glacier, where a major (1.5 km3) six months long eruption took place. Intense earthquake activity in the caldera started in the period August 21-24 with over 70 M5 earthquakes accompanying slow caldera collapse, as verified by various geodetic measurements. The subsidence is likely due to magma withdrawal from a reservoir at depth beneath the caldera. During a five months period, October-February, the seismic activity was separated by over 30 km in two clusters; one along the caldera rims (due to piecewise caldera subsidence) and the other at the far end of the dyke (as a result of small shear movements). Here we present statistical analysis comparing the temporal behaviour of seismicity recorded in the two clusters. By comparing the earthquake rate in the dyke in temporal bins before and after caldera subsidence earthquakes to the rate away from these bins (background rate), we show that the number of dyke earthquakes was significantly higher (p <0.05) in the period 0-3 hours before a large earthquake (>M4.6) in the caldera. Increased dyke seismicity was also observed 0-3 hours following a large caldera earthquake. Elevated seismicity in the dyke before a large caldera earthquake may occur when a constriction in the dyke was reduced, followed by pressure drop in the chamber. Assuming that the large caldera earthquakes occurred when chamber pressure was lowest, the subsiding caldera piston may have caused temporary higher pressure in the dyke and thereby increased

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

    USGS Publications Warehouse

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

    2014-01-01

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

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

    PubMed

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

    2014-08-21

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

  12. Topographic changes and their driving factors after 2008 Wenchuan Earthquake

    NASA Astrophysics Data System (ADS)

    Li, C.; Wang, M.; Xie, J.; Liu, K.

    2017-12-01

    The Wenchuan Ms 8.0 Earthquake caused topographic change in the stricken areas because of the formation of numerous coseismic landslides. The emergence of new landslides and debris flows and movement of loose materials under the driving force of heavy rainfall could further shape the local topography. Dynamic topographic changes in mountainous areas stricken by major earthquakes have a strong linkage to the development and occurrence of secondary disasters. However, little attention has been paid to continuously monitoring mountain environment change after such earthquakes. A digital elevation model (DEM) is the main feature of the terrain surface, in our research, we extracted DEM in 2013 and 2015 of a typical mountainous area severely impacted by the 2008 Wenchuan earthquake from the ZY-3 stereo pair images with validation by field measurement. Combined with the elevation dataset in 2002 and 2010, we quantitatively assessed elevation changes in different years and qualitatively analyzed spatiotemporal variation of the terrain and mass movement across the study area. The results show that the earthquake stricken area experienced substantial elevation changes caused by seismic forces and subsequent rainfalls. Meanwhile, deposits after the earthquake are mainly accumulated on the river-channels and mountain ridges and deep gullies which increase the risk of other geo-hazards. And the heavy rainfalls after the earthquake have become the biggest driver of elevation reduction, which overwhelmed elevation increase during the major earthquake. Our study provided a better understanding of subsequent hazards and risks faced by residents and communities stricken by major earthquakes.

  13. Differential energy radiation from two earthquakes in Japan with identical Mw: The Kyushu 1996 and Tottori 2000 earthquakes

    USGS Publications Warehouse

    Choy, G.L.; Boatwright, J.

    2009-01-01

    We examine two closely located earthquakes in Japan that had identical moment magnitudes Mw but significantly different energy magnitudes Me. We use teleseismic data from the Global Seismograph Network and strong-motion data from the National Research Institute for Earth Science and Disaster Prevention's K-Net to analyze the 19 October 1996 Kyushu earthquake (Mw 6.7, Me 6.6) and the 6 October 2000 Tottori earthquake (Mw 6.7, Me 7.4). To obtain regional estimates of radiated energy ES we apply a spectral technique to regional (<200 km) waveforms that are dominated by S and Lg waves. For the thrust-fault Kyushu earthquake, we estimate an average regional attenuation Q(f) 230f0:65. For the strike-slip Tottori earthquake, the average regional attenuation is Q(f) 180f0:6. These attenuation functions are similar to those derived from studies of both California and Japan earthquakes. The regional estimate of ES for the Kyushu earthquake, 3:8 ?? 1014 J, is significantly smaller than that for the Tottori earthquake, ES 1:3 ?? 1015 J. These estimates correspond well with the teleseismic estimates of 3:9 ?? 1014 J and 1:8 ?? 1015 J, respectively. The apparent stress (Ta = ??Es/M0 with ?? equal to rigidity) for the Kyushu earthquake is 4 times smaller than the apparent stress for the Tottori earthquake. In terms of the fault maturity model, the significantly greater release of energy by the strike-slip Tottori earthquake can be related to strong deformation in an immature intraplate setting. The relatively lower energy release of the thrust-fault Kyushu earthquake can be related to rupture on mature faults at a subduction environment. The consistence between teleseismic and regional estimates of ES is particularly significant as teleseismic data for computing ES are routinely available for all large earthquakes whereas often there are no near-field data.

  14. Influence of living environments and working status on low back pain for survivors of the Great East Japan Earthquake.

    PubMed

    Hagiwara, Yoshihiro; Yabe, Yutaka; Sugawara, Yumi; Sato, Mari; Watanabe, Takashi; Kanazawa, Kenji; Sonofuchi, Kazuaki; Koide, Masashi; Sekiguchi, Takuya; Tsuchiya, Masahiro; Tsuji, Ichiro; Itoi, Eiji

    2016-03-01

    The Great East Japan Earthquake and devastating Tsunami caused irreparable damage on the northeastern coast of Japan. This study aimed to examine the influencing factors of "Living environment" and "Working status" on low back pain for the survivors of the earthquake evaluated by a self-report questionnaire. Between 2011 and 2013, survivors replied to the self-report questionnaire, and 986 people consented to join this study. The living environment was divided into 3 categories (1. Living in the same house as before the earthquake, 2. Living in a safe shelter or temporary small house, 3. Living in a house of relatives or apartment house) and working status was divided into 5 categories (1. Unemployed before the earthquake, 2. Unemployed after the earthquake, 3. Decrease in income, 4. Different occupation after the earthquake, 5. The same occupation as before the earthquake). Age, gender, living areas, past history of arthritis, arthropathy, osteoporosis, sleep disturbance, psychological distress, and economic status were considered as confounding factors. Generalized estimating regression models with logit link function were used because outcome variables are repeatedly measured and binomial. We evaluated the correlation between the presence/severity of low back pain over time and housing status/working status at 1 year after the earthquake. There were no significant differences between age, gender, living areas, working status, or living environment before or after the earthquake. There was no significant difference in the risk of having low back pain in living environment or gender. There was significant difference in the risk of having low back pain in those with "Decrease in income" (OR = 1.93, 95% CI = 1.23-3.03) and "The same occupation as before the earthquake" (OR = 1.67, 95% CI = 1.1-2.52). Though living environment has little effect, "Decrease in income" and "The same occupation as before the earthquake" have strong influences on low back pain

  15. 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

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

    NASA Astrophysics Data System (ADS)

    Höchner, Andreas; Babeyko, Andrey; Zamora, Natalia

    2014-05-01

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

  17. Relocation of the 2012 Ms 7.0 Lushan Earthquake Aftershock Sequences and Its Implications

    NASA Astrophysics Data System (ADS)

    Fang, L.; Wu, J.; Sun, Z.; Su, J.; Du, W.

    2013-12-01

    bottom of the fault. The focal depths of 28 aftershocks with ML≥4.0 were determined using Himalaya Seismic Array and sPn phase. The focal depths obtained from sPn phase are consistent with HYPODD, which also reveals a northwest-dipping fault. Since the earthquake did not cause significant surface rupture, the seismogenic structure of Lushan earthquake remains controversial. On the basis of aftershock relocation results, we speculate that the seismogenic fault of Lushan earthquake may be a blind thrust fault on the eastern side of the Shuangshi-Dachuan fault. The relocation results also reveal that there is a southeastward tilt aftershock belt intersecting with the seismogenic fault with y-shape. We infer that it is a back thrust fault that often appears in a thrust fault system. Lushan earthquake triggered the seismic activity of the back thrust fault.

  18. 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.

  19. Geological structures control on earthquake ruptures: The Mw7.7, 2013, Balochistan earthquake, Pakistan

    NASA Astrophysics Data System (ADS)

    Vallage, A.; Klinger, Y.; Lacassin, R.; Delorme, A.; Pierrot-Deseilligny, M.

    2016-10-01

    The 2013 Mw7.7 Balochistan earthquake, Pakistan, ruptured the Hoshab fault. Left-lateral motion dominated the deformation pattern, although significant vertical motion is found along the southern part of the rupture. Correlation of high-resolution (2.5 m) optical satellite images provided horizontal displacement along the entire rupture. In parallel, we mapped the ground rupture geometry at 1:500 scale. We show that the azimuth of the ground rupture distributes mainly between two directions, N216° and N259°. The direction N216° matches the direction of preexisting geologic structures resulting from penetrative deformation caused by the nearby Makran subduction. Hence, during a significant part of its rupture, the 2013 Balochistan rupture kept switching between a long-term fault front and secondary branches, in which existence and direction are related to the compressional context. It shows unambiguous direct interactions between different preexisting geologic structures, regional stress, and dynamic-rupture stress, which controlled earthquake propagation path.

  20. Earthquake Early Warning: A Prospective User's Perspective (Invited)

    NASA Astrophysics Data System (ADS)

    Nishenko, S. P.; Savage, W. U.; Johnson, T.

    2009-12-01

    system, limiting the time available for an EEW-based response (i.e., slowing or stopping trains). While EEW systems are currently being tested in California, the societal benefits may be even more pronounced in other earthquake-prone parts of the United States. In the central and eastern United States, strong ground motions are felt over significantly larger areas than in California, enabling both a larger area and longer lead times for warnings ahead of the arrival of strong shaking. Because these regions are less resistant to earthquake shaking, such warnings may be even more important for safety and emergency response. However, in many areas a significant increase in the instrumentation density would be required for EEW to become a reality. Although the details of EEW systems are specific to earthquakes, the operation of sensor networks, real-time data analysis, and rapid notification to lifelines is an emerging technology that can be used for real-time detection and early warning of other types of natural and human-caused disasters and emergencies.

  1. Coseismic fault zone deformation caused by the 2014 Mw=6.2 Nagano-ken-hokubu, Japan, earthquake on the Itoigawa-Shizuoka Tectonic Line revealed with differential LiDAR

    NASA Astrophysics Data System (ADS)

    Toda, S.; Ishimura, D.; Homma, S.; Mukoyama, S.; Niwa, Y.

    2015-12-01

    The Mw = 6.2 Nagano-ken-hokubu earthquake struck northern Nagano, central Japan, on November 22, 2014, and accompanied a 9-km-long surface rupture mostly along the previously mapped N-NW trending Kamishiro fault, one of the segments of the 150-km-long Itoigawa-Shizuoka Tectonic Line active fault system. While we mapped the rupture and measured vertical displacement of up to 80 cm at the field, interferometric synthetic aperture radar (InSAR) shows densely spaced fringes on the hanging wall side, suggesting westward or uplift movement associated with thrust faulting. The mainshock focal mechanism and aftershock hypocenters indicate the source fault dips to the east but the InSAR images cannot exactly differentiate between horizontal and vertical movements and also lose coherence within and near the fault zone itself. To reveal near-field deformation and shallow fault slip, here we demonstrate a differential LiDAR analysis using a pair of 1 m-resolution pre-event and post-event bare Earth digital terrain models (DTMs) obtained from commercial LiDAR provider. We applied particle image velocity (PIV) method incorporating elevation change to obtain 3-D vectors of coseismic displacements (Mukoyama, 2011, J. Mt. Sci). Despite sporadic noises mostly due to local landslides, we detected up to 1.5 m net movement at the tip of the hanging wall, more than the field measurement of 80 cm. Our result implies that a 9-km-long rupture zone is not a single continuous fault but composed of two bow-shaped fault strands, suggesting a combination of shallow fault dip and modest amount (< 1.5 m) of slip. Eastward movement without notable subsidence on the footwall also supports the low angle fault dip near the surface, and significant fault normal contraction, observed as buckled cultural features across the fault zone. Secondary features, such as subsidiary back-thrust faults confirmed at the field, are also visible as a significant contrast of vector directions and slip amounts.

  2. Monitoring Seismic Velocity Change to Explore the Earthquake Seismogenic Structures

    NASA Astrophysics Data System (ADS)

    Liao, C. F.; Wen, S.; Chen, C.

    2017-12-01

    Studying spatial-temporal variations of subsurface velocity structures is still a challenge work, but it can provide important information not only on geometry of a fault, but also the rheology change induced from the strong earthquake. In 1999, a disastrous Chi-Chi earthquake (Mw7.6; Chi-Chi EQ) occurred in central Taiwan and caused great impacts on Taiwan's society. Therefore, the major objective of this research is to investigate whether the rheology change of fault can be associated with seismogenic process before strong earthquake. In addition, after the strike of the Chi-Chi EQ, whether the subsurface velocity structure resumes to its steady state is another issue in this study. Therefore, for the above purpose, we have applied a 3D tomographic technique to obtain P- and S-wave velocity structures in central Taiwan using travel time data provided by the Central Weather Bureau (CWB). One major advantage of this method is that we can include out-of-network data to improve the resolution of velocity structures at deeper depths in our study area. The results show that the temporal variations of Vp are less significant than Vs (or Vp/Vs ratio), and Vp is not prominent perturbed before and after the occurrence of the Chi-Chi EQ. However, the Vs (or Vp/Vs ratio) structure in the source area demonstrates significant spatial-temporal difference before and after the mainshock. From the results, before the mainshock, Vs began to decrease (Vp/Vs ratio was increased as well) at the hanging wall of Chelungpu fault, which may be induced by the increasing density of microcracks and fluid. But in the vicinities of Chi-Chi Earthquake's source area, Vs was increasing (Vp/Vs ratio was also decreased). This phenomenon may be owing to the closing of cracks or migration of fluid. Due to the different physical characteristics around the source area, strong earthquake may be easily nucleated at the junctional zone. Our findings suggest that continuously monitoring the Vp and Vs (or

  3. 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.

  4. Earthquake prediction; new studies yield promising results

    USGS Publications Warehouse

    Robinson, R.

    1974-01-01

    On Agust 3, 1973, a small earthquake (magnitude 2.5) occurred near Blue Mountain Lake in the Adirondack region of northern New York State. This seemingly unimportant event was of great significance, however, because it was predicted. Seismologsits at the Lamont-Doherty geologcal Observatory of Columbia University accurately foretold the time, place, and magnitude of the event. Their prediction was based on certain pre-earthquake processes that are best explained by a hypothesis known as "dilatancy," a concept that has injected new life and direction into the science of earthquake prediction. Although much mroe reserach must be accomplished before we can expect to predict potentially damaging earthquakes with any degree of consistency, results such as this indicate that we are on a promising road. 

  5. Supercomputing meets seismology in earthquake exhibit

    ScienceCinema

    Blackwell, Matt; Rodger, Arthur; Kennedy, Tom

    2018-02-14

    When the California Academy of Sciences created the "Earthquake: Evidence of a Restless Planet" exhibit, they called on Lawrence Livermore to help combine seismic research with the latest data-driven visualization techniques. The outcome is a series of striking visualizations of earthquakes, tsunamis and tectonic plate evolution. Seismic-wave research is a core competency at Livermore. While most often associated with earthquakes, the research has many other applications of national interest, such as nuclear explosion monitoring, explosion forensics, energy exploration, and seismic acoustics. For the Academy effort, Livermore researchers simulated the San Andreas and Hayward fault events at high resolutions. Such calculations require significant computational resources. To simulate the 1906 earthquake, for instance, visualizing 125 seconds of ground motion required over 1 billion grid points, 10,000 time steps, and 7.5 hours of processor time on 2,048 cores of Livermore's Sierra machine.

  6. Testing prediction methods: Earthquake clustering versus the Poisson model

    USGS Publications Warehouse

    Michael, A.J.

    1997-01-01

    Testing earthquake prediction methods requires statistical techniques that compare observed success to random chance. One technique is to produce simulated earthquake catalogs and measure the relative success of predicting real and simulated earthquakes. The accuracy of these tests depends on the validity of the statistical model used to simulate the earthquakes. This study tests the effect of clustering in the statistical earthquake model on the results. Three simulation models were used to produce significance levels for a VLF earthquake prediction method. As the degree of simulated clustering increases, the statistical significance drops. Hence, the use of a seismicity model with insufficient clustering can lead to overly optimistic results. A successful method must pass the statistical tests with a model that fully replicates the observed clustering. However, a method can be rejected based on tests with a model that contains insufficient clustering. U.S. copyright. Published in 1997 by the American Geophysical Union.

  7. Turkish Compulsory Earthquake Insurance and "Istanbul Earthquake

    NASA Astrophysics Data System (ADS)

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

    2009-04-01

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

  8. Great East Japan Earthquake Tsunami

    NASA Astrophysics Data System (ADS)

    Iijima, Y.; Minoura, K.; Hirano, S.; Yamada, T.

    2011-12-01

    The 11 March 2011, Mw 9.0 Great East Japan Earthquake, already among the most destructive earthquakes in modern history, emanated from a fault rupture that extended an estimated 500 km along the Pacific coast of Honshu. This earthquake is the fourth among five of the strongest temblors since AD 1900 and the largest in Japan since modern instrumental recordings began 130 years ago. The earthquake triggered a huge tsunami, which invaded the seaside areas of the Pacific coast of East Japan, causing devastating damages on the coast. Artificial structures were destroyed and planted forests were thoroughly eroded. Inrush of turbulent flows washed backshore areas and dunes. Coastal materials including beach sand were transported onto inland areas by going-up currents. Just after the occurrence of the tsunami, we started field investigation of measuring thickness and distribution of sediment layers by the tsunami and the inundation depth of water in Sendai plain. Ripple marks showing direction of sediment transport were the important object of observation. We used a soil auger for collecting sediments in the field, and sediment samples were submitted for analyzing grain size and interstitial water chemistry. Satellite images and aerial photographs are very useful for estimating the hydrogeological effects of tsunami inundation. We checked the correspondence of micro-topography, vegetation and sediment covering between before and after the tsunami. The most conspicuous phenomenon is the damage of pine forests planted in the purpose of preventing sand shifting. About ninety-five percent of vegetation coverage was lost during the period of rapid currents changed from first wave. The landward slopes of seawalls were mostly damaged and destroyed. Some aerial photographs leave detailed records of wave destruction just behind seawalls, which shows the occurrence of supercritical flows. The large-scale erosion of backshore behind seawalls is interpreted to have been caused by

  9. Earthquake and submarine landslide tsunamis: how can we tell the difference? (Invited)

    NASA Astrophysics Data System (ADS)

    Tappin, D. R.; Grilli, S. T.; Harris, J.; Geller, R. J.; Masterlark, T.; Kirby, J. T.; Ma, G.; Shi, F.

    2013-12-01

    Several major recent events have shown the tsunami hazard from submarine mass failures (SMF), i.e., submarine landslides. In 1992 a small earthquake triggered landslide generated a tsunami over 25 meters high on Flores Island. In 1998 another small, earthquake-triggered, sediment slump-generated tsunami up to 15 meters high devastated the local coast of Papua New Guinea killing 2,200 people. It was this event that led to the recognition of the importance of marine geophysical data in mapping the architecture of seabed sediment failures that could be then used in modeling and validating the tsunami generating mechanism. Seabed mapping of the 2004 Indian Ocean earthquake rupture zone demonstrated, however, that large, if not great, earthquakes do not necessarily cause major seabed failures, but that along some convergent margins frequent earthquakes result in smaller sediment failures that are not tsunamigenic. Older events, such as Messina, 1908, Makran, 1945, Alaska, 1946, and Java, 2006, all have the characteristics of SMF tsunamis, but for these a SMF source has not been proven. When the 2011 tsunami struck Japan, it was generally assumed that it was directly generated by the earthquake. The earthquake has some unusual characteristics, such as a shallow rupture that is somewhat slow, but is not a 'tsunami earthquake.' A number of simulations of the tsunami based on an earthquake source have been published, but in general the best results are obtained by adjusting fault rupture models with tsunami wave gauge or other data so, to the extent that they can model the recorded tsunami data, this demonstrates self-consistency rather than validation. Here we consider some of the existing source models of the 2011 Japan event and present new tsunami simulations based on a combination of an earthquake source and an SMF mapped from offshore data. We show that the multi-source tsunami agrees well with available tide gauge data and field observations and the wave data from

  10. Modified-Fibonacci-Dual-Lucas method for earthquake prediction

    NASA Astrophysics Data System (ADS)

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

    2015-06-01

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

  11. A century of induced earthquakes in Oklahoma?

    USGS Publications Warehouse

    Hough, Susan E.; Page, Morgan T.

    2015-01-01

    Seismicity rates have increased sharply since 2009 in the central and eastern United States, with especially high rates of activity in the state of Oklahoma. Growing evidence indicates that many of these events are induced, primarily by injection of wastewater in deep disposal wells. The upsurge in activity has raised two questions: What is the background rate of tectonic earthquakes in Oklahoma? How much has the rate varied throughout historical and early instrumental times? In this article, we show that (1) seismicity rates since 2009 surpass previously observed rates throughout the twentieth century; (2) several lines of evidence suggest that most of the significant earthquakes in Oklahoma during the twentieth century were likely induced by oil production activities, as they exhibit statistically significant temporal and spatial correspondence with disposal wells, and intensity measurements for the 1952 El Reno earthquake and possibly the 1956 Tulsa County earthquake follow the pattern observed in other induced earthquakes; and (3) there is evidence for a low level of tectonic seismicity in southeastern Oklahoma associated with the Ouachita structural belt. The 22 October 1882 Choctaw Nation earthquake, for which we estimate Mw 4.8, occurred in this zone.

  12. Modeling Channel Movement Response to Rainfall Variability and Potential Threats to Post-earthquake Reconstruction

    NASA Astrophysics Data System (ADS)

    Xie, J.; Wang, M.; Liu, K.

    2017-12-01

    The 2008 Wenchuan Ms 8.0 earthquake caused overwhelming destruction to vast mountains areas in Sichuan province. Numerous seismic landslides damaged the forest and vegetation cover, and caused substantial loose sediment piling up in the valleys. The movement and fill-up of loose materials led to riverbeds aggradation, thus made the earthquake-struck area more susceptible to flash floods with increasing frequency and intensity of extreme rainfalls. This study investigated the response of sediment and river channel evolution to different rainfall scenarios after the Wenchuan earthquake. The study area was chosen in a catchment affected by the earthquake in Northeast Sichuan province, China. We employed the landscape evolution model CAESAR-lisflood to explore the material migration rules and then assessed the potential effects under two rainfall scenarios. The model parameters were calibrated using the 2013 extreme rainfall event, and the experimental rainfall scenarios were of different intensity and frequency over a 10-year period. The results indicated that CAESAR-lisflood was well adapted to replicate the sediment migration, particularly the fluvial processes after earthquake. With respect to the effects of rainfall intensity, the erosion severity in upstream gullies and the deposition severity in downstream channels, correspondingly increased with the increasing intensity of extreme rainfalls. The modelling results showed that buildings in the catchment suffered from flash floods increased by more than a quarter from the normal to the enhanced rainfall scenarios in ten years, which indicated a potential threat to the exposures nearby the river channel, in the context of climate change. Simulation on landscape change is of great significance, and contributes to early warning of potential geological risks after earthquake. Attention on the high risk area by local government and the public is highly suggested in our study.

  13. A post-Tohoku earthquake review of earthquake probabilities in the Southern Kanto District, Japan

    NASA Astrophysics Data System (ADS)

    Somerville, Paul G.

    2014-12-01

    The 2011 Mw 9.0 Tohoku earthquake generated an aftershock sequence that affected a large part of northern Honshu, and has given rise to widely divergent forecasts of changes in earthquake occurrence probabilities in northern Honshu. The objective of this review is to assess these forecasts as they relate to potential changes in the occurrence probabilities of damaging earthquakes in the Kanto Region. It is generally agreed that the 2011 Mw 9.0 Tohoku earthquake increased the stress on faults in the southern Kanto district. Toda and Stein (Geophys Res Lett 686, 40: doi:10.1002, 2013) further conclude that the probability of earthquakes in the Kanto Corridor has increased by a factor of 2.5 for the time period 11 March 2013 to 10 March 2018 in the Kanto Corridor. Estimates of earthquake probabilities in a wider region of the Southern Kanto District by Nanjo et al. (Geophys J Int, doi:10.1093, 2013) indicate that any increase in the probability of earthquakes is insignificant in this larger region. Uchida et al. (Earth Planet Sci Lett 374: 81-91, 2013) conclude that the Philippine Sea plate the extends well north of the northern margin of Tokyo Bay, inconsistent with the Kanto Fragment hypothesis of Toda et al. (Nat Geosci, 1:1-6,2008), which attributes deep earthquakes in this region, which they term the Kanto Corridor, to a broken fragment of the Pacific plate. The results of Uchida and Matsuzawa (J Geophys Res 115:B07309, 2013)support the conclusion that fault creep in southern Kanto may be slowly relaxing the stress increase caused by the Tohoku earthquake without causing more large earthquakes. Stress transfer calculations indicate a large stress transfer to the Off Boso Segment as a result of the 2011 Tohoku earthquake. However, Ozawa et al. (J Geophys Res 117:B07404, 2012) used onshore GPS measurements to infer large post-Tohoku creep on the plate interface in the Off-Boso region, and Uchida and Matsuzawa (ibid.) measured similar large creep off the Boso

  14. Preliminary report on crustal deformation surveys and tsunami measurements due to the July 17, 2006 Java Earthquake and Tsunami, Indonesia

    NASA Astrophysics Data System (ADS)

    Kato, T.; Ito, T.; Abidin, H. Z.; Agustan, A.

    2006-12-01

    A large earthquake along a plate boundary occurred in the south of Java Island on July 17, 2006, whose magnitude was 7.7 (USGS) and caused significant tsunami. We made GPS observations and tsunami heights measurements during the period from July 24 to August 1, 2006. The earthquake seems to be due to an interplate low angle reverse faulting (e.g. Yagi, 2006). Yet, there would be a possibility of high angle faulting within the subducting lithosphere (e.g., Yamanaka, 2006). Crustal deformation distribution due to the earthquake, aided by tsunami heights measurements, might clarify which would be the case. We occupied 29 sites by GPS in the area of southern Java Island encompassing the area from 107.8E to 109.50E. These sites were occupied once before the earthquake so that co-seismic displacements might be seen. If we assume that the slip on the fault surface is as that estimated assuming magnitude to be 7.7, co- seismic displacements would be as small as a few centimeters or less. However, the tsunami heights measurements at 11 sites that were conducted along with the GPS observation were 6-7m along the southern coast of Java Islands and indicates that the observed heights are systematically higher than that estimated from numerical simulations (e.g., Koshimura, 2006). This might suggest that fault offsets have been larger nearly double - than that estimated using seismic analysis. If this is the case, the co-seismic crustal movements might be larger than above estimation. This might lead us to an idea that the rupture was very slow and did not radiate enough seismic energy to underestimate the earthquake magnitude. If this is the case, the earthquake might have been a "tsunami earthquake" that is similar to the one that occurred on June 2, 1994 in the east of the present earthquake.

  15. Altered lipid peroxidation markers are related to post-traumatic stress disorder (PTSD) and not trauma itself in earthquake survivors.

    PubMed

    Atli, Abdullah; Bulut, Mahmut; Bez, Yasin; Kaplan, İbrahim; Özdemir, Pınar Güzel; Uysal, Cem; Selçuk, Hilal; Sir, Aytekin

    2016-06-01

    The traumatic life events, including earthquakes, war, and interpersonal conflicts, cause a cascade of psychological and biological changes known as post-traumatic stress disorder (PTSD). Malondialdehyde (MDA) is a reliable marker of lipid peroxidation, and paraoxonase is a known antioxidant enzyme. The aims of this study were to investigate the relationship between earthquake trauma, PTSD effects on oxidative stress and the levels of serum paraoxonase 1 (PON1) enzyme activity, and levels of serum MDA. The study was carried out on three groups called: the PTSD group, the traumatized with earthquake exercise group, and healthy control group, which contained 32, 31, and 38 individuals, respectively. Serum MDA levels and PON1 enzyme activities from all participants were measured, and the results were compared across all groups. There were no significant differences between the PTSD patients and non-PTSD earthquake survivors in terms of the study variables. The mean PON1 enzyme activity from PTSD patients was significantly lower, while the mean MDA level was significantly higher than that of the healthy control group (p < 0.01 for both measurements). Similarly, earthquake survivors who did not develop PTSD showed higher MDA levels and lower PON1 activity when compared to healthy controls. However, the differences between these groups did not reach a statistically significant level. Increased MDA level and decreased PON1 activity measured in PTSD patients after earthquake and may suggest increased oxidative stress in these patients. The nonsignificant trends that are observed in lipid peroxidation markers of earthquake survivors may indicate higher impact of PTSD development on these markers than trauma itself. For example, PTSD diagnosis seems to add to the effect of trauma on serum MDA levels and PON1 enzyme activity. Thus, serum MDA levels and PON1 enzyme activity may serve as biochemical markers of PTSD diagnosis.

  16. Observing Triggered Earthquakes Across Iran with Calibrated Earthquake Locations

    NASA Astrophysics Data System (ADS)

    Karasozen, E.; Bergman, E.; Ghods, A.; Nissen, E.

    2016-12-01

    We investigate earthquake triggering phenomena in Iran by analyzing patterns of aftershock activity around mapped surface ruptures. Iran has an intense level of seismicity (> 40,000 events listed in the ISC Bulletin since 1960) due to it accommodating a significant portion of the continental collision between Arabia and Eurasia. There are nearly thirty mapped surface ruptures associated with earthquakes of M 6-7.5, mostly in eastern and northwestern Iran, offering a rich potential to study the kinematics of earthquake nucleation, rupture propagation, and subsequent triggering. However, catalog earthquake locations are subject to up to 50 km of location bias from the combination of unknown Earth structure and unbalanced station coverage, making it challenging to assess both the rupture directivity of larger events and the spatial patterns of their aftershocks. To overcome this limitation, we developed a new two-tiered multiple-event relocation approach to obtain hypocentral parameters that are minimally biased and have realistic uncertainties. In the first stage, locations of small clusters of well-recorded earthquakes at local spatial scales (100s of events across 100 km length scales) are calibrated either by using near-source arrival times or independent location constraints (e.g. local aftershock studies, InSAR solutions), using an implementation of the Hypocentroidal Decomposition relocation technique called MLOC. Epicentral uncertainties are typically less than 5 km. Then, these events are used as prior constraints in the code BayesLoc, a Bayesian relocation technique that can handle larger datasets, to yield region-wide calibrated hypocenters (1000s of events over 1000 km length scales). With locations and errors both calibrated, the pattern of aftershock activity can reveal the type of the earthquake triggering: dynamic stress changes promote an increase in the seismicity rate in the direction of unilateral propagation, whereas static stress changes should

  17. Earthquakes, September-October 1986

    USGS Publications Warehouse

    Person, W.J.

    1987-01-01

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

  18. Will weight loss cause significant dosimetric changes of target volumes and organs at risk in nasopharyngeal carcinoma treated with intensity-modulated radiation therapy?

    SciTech Connect

    Chen, Chuanben; Fei, Zhaodong; Chen, Lisha

    This study aimed to quantify dosimetric effects of weight loss for nasopharyngeal carcinoma (NPC) treated with intensity-modulated radiation therapy (IMRT). Overall, 25 patients with NPC treated with IMRT were enrolled. We simulated weight loss during IMRT on the computer. Weight loss model was based on the planning computed tomography (CT) images. The original external contour of head and neck was labeled plan 0, and its volume was regarded as pretreatment normal weight. We shrank the external contour with different margins (2, 3, and 5 mm) and generated new external contours of head and neck. The volumes of reconstructed external contoursmore » were regarded as weight during radiotherapy. After recontouring outlines, the initial treatment plan was mapped to the redefined CT scans with the same beam configurations, yielding new plans. The computer model represented a theoretical proportional weight loss of 3.4% to 13.7% during the course of IMRT. The dose delivered to the planning target volume (PTV) of primary gross tumor volume and clinical target volume significantly increased by 1.9% to 2.9% and 1.8% to 2.9% because of weight loss, respectively. The dose to the PTV of gross tumor volume of lymph nodes fluctuated from −2.0% to 1.0%. The dose to the brain stem and the spinal cord was increased (p < 0.001), whereas the dose to the parotid gland was decreased (p < 0.001). Weight loss may lead to significant dosimetric change during IMRT. Repeated scanning and replanning for patients with NPC with an obvious weight loss may be necessary.« less

  19. Combining historical and geomorphological information to investigate earthquake induced landslides

    NASA Astrophysics Data System (ADS)

    Cardinali, M.; Ferrari, G.; Galli, M.; Guidoboni, E.; Guzzetti, F.

    2003-04-01

    Landslides are caused by many different triggers, including earthquakes. In Italy, a detailed new generation catalogue of information on historical earthquakes for the period 461 B.C to 1997 is available (Catalogue of Strong Italian Earthquakes from 461 B.C. to 1997, ING-SGA 2000). The catalogue lists 548 earthquakes and provides information on a total of about 450 mass-movements triggered by 118 seismic events. The information on earthquake-induced landslides listed in the catalogue was obtained through the careful scrutiny of historical documents and chronicles, but was rarely checked in the field. We report on an attempt to combine the available historical information on landslides caused by earthquakes with standard geomorphological techniques, including the interpretation of aerial photographs and field surveys, to better determine the location, type and distribution of seismically induced historical slope failures. We present four examples in the Central Apennines. The first example describes a rock slide triggered by the 1279 April 30 Umbria-Marche Apennines earthquake (Io = IX) at Serravalle, along the Chienti River (Central Italy). The landslide is the oldest known earthquake-induced slope failure in Italy. The second example describes the location of 2 large landslides triggered by the 1584 September 10 earthquake (Io = IX) at San Piero in Bagno, along the Savio River (Northern Italy). The landslides were subsequently largely modified by mass movements occurred on 1855 making the recognition of the original seismically induced failures difficult, if not impossible. In the third example we present the geographical distribution of the available information on landslide events triggered by 8 earthquakes in Central Valnerina, in the period 1703 to 1979. A comparison with the location of landslides triggered by the September-October 1997 Umbria-Marche earthquake sequence is presented. The fourth example describes the geographical distribution of the available

  20. 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.  

  1. Combined GPS and InSAR models of postseismic deformation from the Northridge Earthquake

    NASA Technical Reports Server (NTRS)

    Donnellan, A.; Parker, J. W.; Peltzer, G.

    2002-01-01

    Models of combined Global Positioning System and Interferometric Synthetic Aperture Radar data collected in the region of the Northridge earthquake indicate that significant afterslip on the main fault occurred following the earthquake.

  2. Prediction of earthquake-triggered landslide event sizes

    NASA Astrophysics Data System (ADS)

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

    2016-04-01

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

  3. Implications for earthquake risk reduction in the United States from the Kocaeli, Turkey, earthquake of August 17, 1999

    USGS Publications Warehouse

    ,

    2000-01-01

    This report documents implications for earthquake risk reduction in the U.S. The magnitude 7.4 earthquake caused 17,127 deaths, 43,953 injuries, and displaced more than 250,000 people from their homes. The report warns that similar disasters are possible in the United States where earthquakes of comparable size strike the heart of American urban areas. Another concern described in the report is the delayed emergency response that was caused by the inadequate seismic monitoring system in Turkey, a problem that contrasts sharply with rapid assessment and response to the September Chi-Chi earthquake in Taiwan. Additionally, the experience in Turkey suggests that techniques for forecasting earthquakes may be improving.

  4. Seismic databases and earthquake catalogue of the Caucasus

    NASA Astrophysics Data System (ADS)

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

    2016-04-01

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

  5. Is earthquake rate in south Iceland modified by seasonal loading?

    NASA Astrophysics Data System (ADS)

    Jonsson, S.; Aoki, Y.; Drouin, V.

    2017-12-01

    Several temporarily varying processes have the potential of modifying the rate of earthquakes in the south Iceland seismic zone, one of the two most active seismic zones in Iceland. These include solid earth tides, seasonal meteorological effects and influence from passing weather systems, and variations in snow and glacier loads. In this study we investigate the influence these processes may have on crustal stresses and stressing rates in the seismic zone and assess whether they appear to be influencing the earthquake rate. While historical earthquakes in the south Iceland have preferentially occurred in early summer, this tendency is less clear for small earthquakes. The local earthquake catalogue (going back to 1991, magnitude of completeness < 1.0) has indeed more earthquakes in summer than in winter. However, this pattern is strongly influenced by aftershock sequences of the largest M6+ earthquakes, which occurred in June 2000 and May 2008. Standard Reasenberg earthquake declustering or more involved model independent stochastic declustering algorithms are not capable of fully eliminating the aftershocks from the catalogue. We therefore inspected the catalogue for the time period before 2000 and it shows limited seasonal tendency in earthquake occurrence. Our preliminary results show no clear correlation between earthquake rates and short-term stressing variations induced from solid earth tides or passing storms. Seasonal meteorological effects also appear to be too small to influence the earthquake activity. Snow and glacier load variations induce significant vertical motions in the area with peak loading occurring in Spring (April-May) and maximum unloading in Fall (Sept.-Oct.). Early summer occurrence of historical earthquakes therefore correlates with early unloading rather than with the peak unloading or unloading rate, which appears to indicate limited influence of this seasonal process on the earthquake activity.

  6. Sun, Moon and Earthquakes

    NASA Astrophysics Data System (ADS)

    Kolvankar, V. G.

    2013-12-01

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

  7. Stress drops of induced and tectonic earthquakes in the central United States are indistinguishable.

    PubMed

    Huang, Yihe; Ellsworth, William L; Beroza, Gregory C

    2017-08-01

    Induced earthquakes currently pose a significant hazard in the central United States, but there is considerable uncertainty about the severity of their ground motions. We measure stress drops of 39 moderate-magnitude induced and tectonic earthquakes in the central United States and eastern North America. Induced earthquakes, more than half of which are shallower than 5 km, show a comparable median stress drop to tectonic earthquakes in the central United States that are dominantly strike-slip but a lower median stress drop than that of tectonic earthquakes in the eastern North America that are dominantly reverse-faulting. This suggests that ground motion prediction equations developed for tectonic earthquakes can be applied to induced earthquakes if the effects of depth and faulting style are properly considered. Our observation leads to the notion that, similar to tectonic earthquakes, induced earthquakes are driven by tectonic stresses.

  8. Stress drops of induced and tectonic earthquakes in the central United States are indistinguishable

    PubMed Central

    Huang, Yihe; Ellsworth, William L.; Beroza, Gregory C.

    2017-01-01

    Induced earthquakes currently pose a significant hazard in the central United States, but there is considerable uncertainty about the severity of their ground motions. We measure stress drops of 39 moderate-magnitude induced and tectonic earthquakes in the central United States and eastern North America. Induced earthquakes, more than half of which are shallower than 5 km, show a comparable median stress drop to tectonic earthquakes in the central United States that are dominantly strike-slip but a lower median stress drop than that of tectonic earthquakes in the eastern North America that are dominantly reverse-faulting. This suggests that ground motion prediction equations developed for tectonic earthquakes can be applied to induced earthquakes if the effects of depth and faulting style are properly considered. Our observation leads to the notion that, similar to tectonic earthquakes, induced earthquakes are driven by tectonic stresses. PMID:28782040

  9. Earthquakes drive focused denudation along a tectonically active mountain front

    NASA Astrophysics Data System (ADS)

    Li, Gen; West, A. Joshua; Densmore, Alexander L.; Jin, Zhangdong; Zhang, Fei; Wang, Jin; Clark, Marin; Hilton, Robert G.

    2017-08-01

    Earthquakes cause widespread landslides that can increase erosional fluxes observed over years to decades. However, the impact of earthquakes on denudation over the longer timescales relevant to orogenic evolution remains elusive. Here we assess erosion associated with earthquake-triggered landslides in the Longmen Shan range at the eastern margin of the Tibetan Plateau. We use the Mw 7.9 2008 Wenchuan and Mw 6.6 2013 Lushan earthquakes to evaluate how seismicity contributes to the erosional budget from short timescales (annual to decadal, as recorded by sediment fluxes) to long timescales (kyr to Myr, from cosmogenic nuclides and low temperature thermochronology). Over this wide range of timescales, the highest rates of denudation in the Longmen Shan coincide spatially with the region of most intense landsliding during the Wenchuan earthquake. Across sixteen gauged river catchments, sediment flux-derived denudation rates following the Wenchuan earthquake are closely correlated with seismic ground motion and the associated volume of Wenchuan-triggered landslides (r2 > 0.6), and to a lesser extent with the frequency of high intensity runoff events (r2 = 0.36). To assess whether earthquake-induced landsliding can contribute importantly to denudation over longer timescales, we model the total volume of landslides triggered by earthquakes of various magnitudes over multiple earthquake cycles. We combine models that predict the volumes of landslides triggered by earthquakes, calibrated against the Wenchuan and Lushan events, with an earthquake magnitude-frequency distribution. The long-term, landslide-sustained "seismic erosion rate" is similar in magnitude to regional long-term denudation rates (∼0.5-1 mm yr-1). The similar magnitude and spatial coincidence suggest that earthquake-triggered landslides are a primary mechanism of long-term denudation in the frontal Longmen Shan. We propose that the location and intensity of seismogenic faulting can contribute to

  10. 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

  11. The Christchurch earthquake stroke incidence study.