Evaluation and implementation of an improved methodology for earthquake ground response analysis : uniform treatment source, path and site effects.

DOT National Transportation Integrated Search

2008-12-01

Shortly after the 1994 Northridge Earthquake, Caltrans geotechnical engineers charged with developing site-specific : response spectra for high priority California bridges initiated a research project aimed at broadening their perspective : from simp...

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.

Ground motion in Anchorage, Alaska, from the 2002 Denali fault earthquake: Site response and Displacement Pulses

USGS Publications Warehouse

Boore, D.M.

2004-01-01

Data from the 2002 Denali fault earthquake recorded at 26 sites in and near Anchorage, Alaska, show a number of systematic features important in studies of site response and in constructing long-period spectra for use in earthquake engineering. The data demonstrate that National Earthquake Hazards Reduction Program (NEHRP) site classes are a useful way of grouping stations according to site amplification. In general, the sites underlain by lower shear-wave velocities have higher amplification. The amplification on NEHRP class D sites exceeds a factor of 2 relative to an average of motions on class C sites. The amplifications are period dependent. They are in rough agreement with those from previous studies, but the new data show that the amplifications extend to at least 10 sec, periods longer than considered in previous studies. At periods longer than about 14 sec, all sites have motion of similar amplitude, and the ground displacements are similar in shape, polarization, and amplitude for all stations. The displacement ground motion is dominated by a series of four pulses, which are associated with the three subevents identified in inversion studies (the first pulse is composed of P waves from the first subevent). Most of the high-frequency ground motion is associated with the S waves from subevent 1. The pulses from subevents 1 and 2, with moment releases corresponding to M 7.1 and 7.0, are similar to the pulse of displacement radiated by the M 7.1 Hector Mine earthquake. The signature from the largest subevent (M 7.6) is more subdued than those from the first two subevents. The two largest pulses produce response spectra with peaks at a period of about 15 sec. The spectral shape at long periods is in good agreement with the recent 2003 NEHRP code spectra but is in poor agreement with the shape obtained from Eurocode 8.

Sensitivity analysis of tall buildings in Semarang, Indonesia due to fault earthquakes with maximum 7 Mw

NASA Astrophysics Data System (ADS)

Partono, Windu; Pardoyo, Bambang; Atmanto, Indrastono Dwi; Azizah, Lisa; Chintami, Rouli Dian

2017-11-01

Fault is one of the dangerous earthquake sources that can cause building failure. A lot of buildings were collapsed caused by Yogyakarta (2006) and Pidie (2016) fault source earthquakes with maximum magnitude 6.4 Mw. Following the research conducted by Team for Revision of Seismic Hazard Maps of Indonesia 2010 and 2016, Lasem, Demak and Semarang faults are three closest earthquake sources surrounding Semarang. The ground motion from those three earthquake sources should be taken into account for structural design and evaluation. Most of tall buildings, with minimum 40 meter high, in Semarang were designed and constructed following the 2002 and 2012 Indonesian Seismic Code. This paper presents the result of sensitivity analysis research with emphasis on the prediction of deformation and inter-story drift of existing tall building within the city against fault earthquakes. The analysis was performed by conducting dynamic structural analysis of 8 (eight) tall buildings using modified acceleration time histories. The modified acceleration time histories were calculated for three fault earthquakes with magnitude from 6 Mw to 7 Mw. The modified acceleration time histories were implemented due to inadequate time histories data caused by those three fault earthquakes. Sensitivity analysis of building against earthquake can be predicted by evaluating surface response spectra calculated using seismic code and surface response spectra calculated from acceleration time histories from a specific earthquake event. If surface response spectra calculated using seismic code is greater than surface response spectra calculated from acceleration time histories the structure will stable enough to resist the earthquake force.

Incredibly distant ionospheric responses to earthquake

NASA Astrophysics Data System (ADS)

Yusupov, Kamil; Akchurin, Adel

2015-04-01

Attempts to observe ionospheric responses to the earthquake has been going on for decades. In recent years, the greatest progress in the study of this question have GPS-measurements with simultaneous HF-measurements. The use of a dense network of GPS-receivers and getting with it sufficiently detailed two-dimensional maps of the total electron content (TEC) greatly clarified the nature of the ionospheric response to strong earthquakes. For ionospheric responses observation, that are remote more than 1000 km from the strong earthquakes epicentres, it is necessary to applying more sensitive methods than GPS. The most experience in the observation of the ionospheric responses to earthquakes accumulated with Doppler sounding. Using these measurements, ionospheric disturbances characteristic features (signature) have been allocated, which associated with the passage of Rayleigh waves on the surface. Particular, this Rayleigh wave signatures allocation is implemented in the Nostradamus coherent backscatter radar. The authors of this method suggest using radar techniques like a sensitive "ionospheric seismometer." The most productive allocation and studying of the vertical structure ionospheric responses could be ionosonde observations. However, their typical 15 minute sounding rate is quite sufficient for observing the regular ionosphere, but it is not enough for studying the ionospheric responses to earthquakes, because ionospheric responses is often seen only in one ionogram and it is absent in adjacent. The decisive factor in establishing the striking ionospheric response to the earthquake was the Tohoku earthquake in 2011, when there was three ionosondes distant at 870-2000 km from the epicentre. These ionosondes simultaneously showed distortion of the F1-layer traces as its multiple stratification (multiple-cusp signature - MCS), which generated by Rayleigh wave. Note that there was another fourth Japanese ionosonde. It is located a little further near boundaries

Streamflow and water well responses to earthquakes.

PubMed

Montgomery, David R; Manga, Michael

2003-06-27

Earthquake-induced crustal deformation and ground shaking can alter stream flow and water levels in wells through consolidation of surficial deposits, fracturing of solid rocks, aquifer deformation, and the clearing of fracture-filling material. Although local conditions affect the type and amplitude of response, a compilation of reported observations of hydrological response to earthquakes indicates that the maximum distance to which changes in stream flow and water levels in wells have been reported is related to earthquake magnitude. Detectable streamflow changes occur in areas within tens to hundreds of kilometers of the epicenter, whereas changes in groundwater levels in wells can occur hundreds to thousands of kilometers from earthquake epicenters.

Earthquake ground motion: Chapter 3

USGS Publications Warehouse

Luco, Nicolas; Kircher, Charles A.; Crouse, C. B.; Charney, Finley; Haselton, Curt B.; Baker, Jack W.; Zimmerman, Reid; Hooper, John D.; McVitty, William; Taylor, Andy

2016-01-01

Most of the effort in seismic design of buildings and other structures is focused on structural design. This chapter addresses another key aspect of the design process—characterization of earthquake ground motion into parameters for use in design. Section 3.1 describes the basis of the earthquake ground motion maps in the Provisions and in ASCE 7 (the Standard). Section 3.2 has examples for the determination of ground motion parameters and spectra for use in design. Section 3.3 describes site-specific ground motion requirements and provides example site-specific design and MCER response spectra and example values of site-specific ground motion parameters. Section 3.4 discusses and provides an example for the selection and scaling of ground motion records for use in various types of response history analysis permitted in the Standard.

Research on response spectrum of dam based on scenario earthquake

NASA Astrophysics Data System (ADS)

Zhang, Xiaoliang; Zhang, Yushan

2017-10-01

Taking a large hydropower station as an example, the response spectrum based on scenario earthquake is determined. Firstly, the potential source of greatest contribution to the site is determined on the basis of the results of probabilistic seismic hazard analysis (PSHA). Secondly, the magnitude and epicentral distance of the scenario earthquake are calculated according to the main faults and historical earthquake of the potential seismic source zone. Finally, the response spectrum of scenario earthquake is calculated using the Next Generation Attenuation (NGA) relations. The response spectrum based on scenario earthquake method is less than the probability-consistent response spectrum obtained by PSHA method. The empirical analysis shows that the response spectrum of scenario earthquake considers the probability level and the structural factors, and combines the advantages of the deterministic and probabilistic seismic hazard analysis methods. It is easy for people to accept and provide basis for seismic engineering of hydraulic engineering.

A Preliminary Analysis on Empirical Attenuation of Absolute Velocity Response Spectra (1 to 10s) in Japan

NASA Astrophysics Data System (ADS)

Dhakal, Y. P.; Kunugi, T.; Suzuki, W.; Aoi, S.

2013-12-01

The Mw 9.1 Tohoku-oki earthquake caused strong shakings of super high rise and high rise buildings constructed on deep sedimentary basins in Japan. Many people felt difficulty in moving inside the high rise buildings even on the Osaka basin located at distances as far as 800 km from the epicentral area. Several empirical equations are proposed to estimate the peak ground motions and absolute acceleration response spectra applicable mainly within 300 to 500km from the source area. On the other hand, Japan Meteorological Agency has recently proposed four classes of absolute velocity response spectra as suitable indices to qualitatively describe the intensity of long-period ground motions based on the observed earthquake records, human experiences, and actual damages that occurred in the high rise and super high rise buildings. The empirical prediction equations have been used in disaster mitigation planning as well as earthquake early warning. In this study, we discuss the results of our preliminary analysis on attenuation relation of absolute velocity response spectra calculated from the observed strong motion records including those from the Mw 9.1 Tohoku-oki earthquake using simple regression models with various model parameters. We used earthquakes, having Mw 6.5 or greater, and focal depths shallower than 50km, which occurred in and around Japanese archipelago. We selected those earthquakes for which the good quality records are available over 50 observation sites combined from K-NET and KiK-net. After a visual inspection on approximately 21,000 three component records from 36 earthquakes, we used about 15,000 good quality records in the period range of 1 to 10s within the hypocentral distance (R) of 800km. We performed regression analyses assuming the following five regression models. (1) log10Y (T) = c+ aMw - log10R - bR (2) log10Y (T) = c+ aMw - log10R - bR +gS (3) log10Y (T) = c+ aMw - log10R - bR + hD (4) log10Y (T) = c+ aMw - log10R - bR +gS +hD (5) log10Y

The ratio between corner frequencies of source spectra of P- and S-waves—a new discriminant between earthquakes and quarry blasts

NASA Astrophysics Data System (ADS)

Ataeva, G.; Gitterman, Y.; Shapira, A.

2017-01-01

This study analyzes and compares the P- and S-wave displacement spectra from local earthquakes and explosions of similar magnitudes. We propose a new approach to discrimination between low-magnitude shallow earthquakes and explosions by using ratios of P- to S-wave corner frequencies as a criterion. We have explored 2430 digital records of the Israeli Seismic Network (ISN) from 456 local events (226 earthquakes, 230 quarry blasts, and a few underwater explosions) of magnitudes Md = 1.4-3.4, which occurred at distances up to 250 km during 2001-2013 years. P-wave and S-wave displacement spectra were computed for all events following Brune's source model of earthquakes (1970, 1971) and applying the distance correction coefficients (Shapira and Hofstetter, Teconophysics 217:217-226, 1993; Ataeva G, Shapira A, Hofstetter A, J Seismol 19:389-401, 2015), The corner frequencies and moment magnitudes were determined using multiple stations for each event, and then the comparative analysis was performed.

Empirical improvements for estimating earthquake response spectra with random‐vibration theory

USGS Publications Warehouse

Boore, David; Thompson, Eric M.

2012-01-01

The stochastic method of ground‐motion simulation is often used in combination with the random‐vibration theory to directly compute ground‐motion intensity measures, thereby bypassing the more computationally intensive time‐domain simulations. Key to the application of random‐vibration theory to simulate response spectra is determining the duration (Drms) used in computing the root‐mean‐square oscillator response. Boore and Joyner (1984) originally proposed an equation for Drms , which was improved upon by Liu and Pezeshk (1999). Though these equations are both substantial improvements over using the duration of the ground‐motion excitation for Drms , we document systematic differences between the ground‐motion intensity measures derived from the random‐vibration and time‐domain methods for both of these Drms equations. These differences are generally less than 10% for most magnitudes, distances, and periods of engineering interest. Given the systematic nature of the differences, however, we feel that improved equations are warranted. We empirically derive new equations from time‐domain simulations for eastern and western North America seismological models. The new equations improve the random‐vibration simulations over a wide range of magnitudes, distances, and oscillator periods.

Analysis of earthquake clustering and source spectra in the Salton Sea Geothermal Field

NASA Astrophysics Data System (ADS)

Cheng, Y.; Chen, X.

2015-12-01

The Salton Sea Geothermal field is located within the tectonic step-over between San Andreas Fault and Imperial Fault. Since the 1980s, geothermal energy exploration has resulted with step-like increase of microearthquake activities, which mirror the expansion of geothermal field. Distinguishing naturally occurred and induced seismicity, and their corresponding characteristics (e.g., energy release) is important for hazard assessment. Between 2008 and 2014, seismic data recorded by a local borehole array were provided public access from CalEnergy through SCEC data center; and the high quality local recording of over 7000 microearthquakes provides unique opportunity to sort out characteristics of induced versus natural activities. We obtain high-resolution earthquake location using improved S-wave picks, waveform cross-correlation and a new 3D velocity model. We then develop method to identify spatial-temporally isolated earthquake clusters. These clusters are classified into aftershock-type, swarm-type, and mixed-type (aftershock-like, with low skew, low magnitude and shorter duration), based on the relative timing of largest earthquakes and moment-release. The mixed-type clusters are mostly located at 3 - 4 km depth near injection well; while aftershock-type clusters and swarm-type clusters also occur further from injection well. By counting number of aftershocks within 1day following mainshock in each cluster, we find that the mixed-type clusters have much higher aftershock productivity compared with other types and historic M4 earthquakes. We analyze detailed spatial variation of 'b-value'. We find that the mixed-type clusters are mostly located within high b-value patches, while large (M>3) earthquakes and other types of clusters are located within low b-value patches. We are currently processing P and S-wave spectra to analyze the spatial-temporal correlation of earthquake stress parameter and seismicity characteristics. Preliminary results suggest that the

Stochastic ground-motion simulation of two Himalayan earthquakes: seismic hazard assessment perspective

NASA Astrophysics Data System (ADS)

Harbindu, Ashish; Sharma, Mukat Lal; Kamal

2012-04-01

The earthquakes in Uttarkashi (October 20, 1991, M w 6.8) and Chamoli (March 8, 1999, M w 6.4) are among the recent well-documented earthquakes that occurred in the Garhwal region of India and that caused extensive damage as well as loss of life. Using strong-motion data of these two earthquakes, we estimate their source, path, and site parameters. The quality factor ( Q β ) as a function of frequency is derived as Q β ( f) = 140 f 1.018. The site amplification functions are evaluated using the horizontal-to-vertical spectral ratio technique. The ground motions of the Uttarkashi and Chamoli earthquakes are simulated using the stochastic method of Boore (Bull Seismol Soc Am 73:1865-1894, 1983). The estimated source, path, and site parameters are used as input for the simulation. The simulated time histories are generated for a few stations and compared with the observed data. The simulated response spectra at 5% damping are in fair agreement with the observed response spectra for most of the stations over a wide range of frequencies. Residual trends closely match the observed and simulated response spectra. The synthetic data are in rough agreement with the ground-motion attenuation equation available for the Himalayas (Sharma, Bull Seismol Soc Am 98:1063-1069, 1998).

Earthquake cycle modeling of multi-segmented faults: dynamic rupture and ground motion simulation of the 1992 Mw 7.3 Landers earthquake.

NASA Astrophysics Data System (ADS)

Petukhin, A.; Galvez, P.; Somerville, P.; Ampuero, J. P.

2017-12-01

simulated ground motions will be validated by comparison of simulated response spectra with recorded response spectra and with response spectra from ground motion prediction models. This research is sponsored by the Japan Nuclear Regulation Authority.

Regional spectral analysis of three moderate earthquakes in Northeastern North America

USGS Publications Warehouse

Boatwright, John; Seekins, Linda C.

2011-01-01

We analyze Fourier spectra obtained from the horizontal components of broadband and accelerogram data from the 1997 Cap-Rouge, the 2002 Ausable Forks, and the 2005 Rivière-du-Loup earthquakes, recorded by Canadian and American stations sited on rock at hypocentral distances from 23 to 602 km. We check the recorded spectra closely for anomalies that might result from site resonance or source effects. We use Beresnev and Atkinson’s (1997) near-surface velocity structures and Boore and Joyner’s (1997) quarter-wave method to estimate site response at hard- and soft-rock sites. We revise the Street et al. (1975) model for geometrical spreading, adopting a crossover distance of ro=50 km instead of 100 km. We obtain an average attenuation of Q=410±25f0.50±0.03 for S+Lg+surface waves with ray paths in the Appalachian and southeastern Grenville Provinces. We correct the recorded spectra for attenuation and site response to estimate source spectral shape and radiated energy for these three earthquakes and the 1988 M 5.8 Saguenay earthquake. The Brune stress drops range from 130 to 419 bars, and the apparent stresses range from 39 to 63 bars. The corrected source spectral shapes of these earthquakes are somewhat variable for frequencies from 0.2 to 2 Hz, falling slightly below the fitted Brune spectra.

Comprehensive analysis of earthquake source spectra and swarms in the Salton Trough, California

NASA Astrophysics Data System (ADS)

Chen, X.; Shearer, P. M.

2011-09-01

We study earthquakes within California's Salton Trough from 1981 to 2009 from a precisely relocated catalog. We process the seismic waveforms to isolate source spectra, station spectra and travel-time dependent spectra. The results suggest an average P wave Q of 340, agreeing with previous results indicating relatively high attenuation in the Salton Trough. Stress drops estimated from the source spectra using an empirical Green's function (EGF) method reveal large scatter among individual events but a low median stress drop of 0.56 MPa for the region. The distribution of stress drop after applying a spatial-median filter indicates lower stress drops near geothermal sites. We explore the relationships between seismicity, stress drops and geothermal injection activities. Seismicity within the Salton Trough shows strong spatial clustering, with 20 distinct earthquake swarms with at least 50 events. They can be separated into early-Mmax and late-Mmax groups based on the normalized occurrence time of their largest event. These swarms generally have a low skew value of moment release history, ranging from -9 to 3.0. The major temporal difference between the two groups is the excess of seismicity and an inverse power law increase of seismicity before the largest event for the late-Mmax group. All swarms exhibit spatial migration of seismicity at a statistical significance greater than 85%. A weighted L1-norm inversion of linear migration parameters yields migration velocities from 0.008 to 0.8 km/hour. To explore the influence of fluid injection in geothermal sites, we also model the migration behavior with the diffusion equation, and obtain a hydraulic diffusion coefficient of approximately 0.25 m2/s for the Salton Sea geothermal site, which is within the range of expected values for a typical geothermal reservoir. The swarms with migration velocities over 0.1 km/hour cannot be explained by the diffusion curve, rather, their velocity is consistent with the propagation

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

USGS Publications Warehouse

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

2011-01-01

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

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.

Control spectra for Quito

NASA Astrophysics Data System (ADS)

Aguiar, Roberto; Rivas-Medina, Alicia; Caiza, Pablo; Quizanga, Diego

2017-03-01

The Metropolitan District of Quito is located on or very close to segments of reverse blind faults, Puengasí, Ilumbisí-La Bota, Carcelen-El Inca, Bellavista-Catequilla and Tangahuilla, making it one of the most seismically dangerous cities in the world. The city is divided into five areas: south, south-central, central, north-central and north. For each of the urban areas, elastic response spectra are presented in this paper, which are determined by utilizing some of the new models of the Pacific Earthquake Engineering Research Center (PEER) NGA-West2 program. These spectra are calculated considering the maximum magnitude that could be generated by the rupture of each fault segment, and taking into account the soil type that exists at different points of the city according to the Norma Ecuatoriana de la Construcción (2015). Subsequently, the recurrence period of earthquakes of high magnitude in each fault segment is determined from the physical parameters of the fault segments (size of the fault plane and slip rate) and the pattern of recurrence of type Gutenberg-Richter earthquakes with double truncation magnitude (Mmin and Mmax) is used.

Real-Time Continuous Response Spectra Exceedance Calculation Displayed in a Web-Browser Enables Rapid and Robust Damage Evaluation by First Responders

NASA Astrophysics Data System (ADS)

Franke, M.; Skolnik, D. A.; Harvey, D.; Lindquist, K.

2014-12-01

A novel and robust approach is presented that provides near real-time earthquake alarms for critical structures at distributed locations and large facilities using real-time estimation of response spectra obtained from near free-field motions. Influential studies dating back to the 1980s identified spectral response acceleration as a key ground motion characteristic that correlates well with observed damage in structures. Thus, monitoring and reporting on exceedance of spectra-based thresholds are useful tools for assessing the potential for damage to facilities or multi-structure campuses based on input ground motions only. With as little as one strong-motion station per site, this scalable approach can provide rapid alarms on the damage status of remote towns, critical infrastructure (e.g., hospitals, schools) and points of interests (e.g., bridges) for a very large number of locations enabling better rapid decision making during critical and difficult immediate post-earthquake response actions. Details on the novel approach are presented along with an example implementation for a large energy company. Real-time calculation of PSA exceedance and alarm dissemination are enabled with Bighorn, an extension module based on the Antelope software package that combines real-time spectral monitoring and alarm capabilities with a robust built-in web display server. Antelope is an environmental data collection software package from Boulder Real Time Technologies (BRTT) typically used for very large seismic networks and real-time seismic data analyses. The primary processing engine produces continuous time-dependent response spectra for incoming acceleration streams. It utilizes expanded floating-point data representations within object ring-buffer packets and waveform files in a relational database. This leads to a very fast method for computing response spectra for a large number of channels. A Python script evaluates these response spectra for exceedance of one or more

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

NASA Astrophysics Data System (ADS)

Shibata, Akenori; Masuno, Hidemasa

2017-10-01

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

Comparison of Human Response against Earthquake and Tsunami

NASA Astrophysics Data System (ADS)

Arikawa, T.; Güler, H. G.; Yalciner, A. C.

2017-12-01

The evacuation response against the earthquake and tsunamis is very important for the reduction of human damages against tsunami. But it is very difficult to predict the human behavior after shaking of the earthquake. The purpose of this research is to clarify the difference of the human response after the earthquake shock in the difference countries and to consider the relation between the response and the safety feeling, knowledge and education. For the objective of this paper, the questionnaire survey was conducted after the 21st July 2017 Gokova earthquake and tsunami. Then, consider the difference of the human behavior by comparison of that in 2015 Chilean earthquake and tsunami and 2011 Japan earthquake and tsunami. The seismic intensity of the survey points was almost 6 to 7. The contents of the questions include the feeling of shaking, recalling of the tsunami, the behavior after shock and so on. The questionnaire was conducted for more than 20 20 people in 10 areas. The results are the following; 1) Most people felt that it was a strong shake not to stand, 2) All of the questionnaires did not recall the tsunami, 3) Depending on the area, they felt that after the earthquake the beach was safer than being at home. 4) After they saw the sea drawing, they thought that a tsunami would come and ran away. Fig. 1 shows the comparison of the evacuation rate within 10 minutes in 2011 Japan, 2015 Chile and 2017 Turkey.. From the education point of view, education for tsunami is not done much in Turkey. From the protection facilities point of view, the high sea walls are constructed only in Japan. From the warning alert point of view, there is no warning system against tsunamis in the Mediterranean Sea. As a result of this survey, the importance of tsunami education is shown, and evacuation tends to be delayed if dependency on facilities and alarms is too high.

Site specific seismic hazard analysis and determination of response spectra of Kolkata for maximum considered earthquake

NASA Astrophysics Data System (ADS)

Shiuly, Amit; Sahu, R. B.; Mandal, Saroj

2017-06-01

This paper presents site specific seismic hazard analysis of Kolkata city, former capital of India and present capital of state West Bengal, situated on the world’s largest delta island, Bengal basin. For this purpose, peak ground acceleration (PGA) for a maximum considered earthquake (MCE) at bedrock level has been estimated using an artificial neural network (ANN) based attenuation relationship developed on the basis of synthetic ground motion data for the region. Using the PGA corresponding to the MCE, a spectrum compatible acceleration time history at bedrock level has been generated by using a wavelet based computer program, WAVEGEN. This spectrum compatible time history at bedrock level has been converted to the same at surface level using SHAKE2000 for 144 borehole locations in the study region. Using the predicted values of PGA and PGV at the surface, corresponding contours for the region have been drawn. For the MCE, the PGA at bedrock level of Kolkata city has been obtained as 0.184 g, while that at the surface level varies from 0.22 g to 0.37 g. Finally, Kolkata has been subdivided into eight seismic subzones, and for each subzone a response spectrum equation has been derived using polynomial regression analysis. This will be very helpful for structural and geotechnical engineers to design safe and economical earthquake resistant structures.

Predominant-period site classification for response spectra prediction equations in Italy

USGS Publications Warehouse

Di Alessandro, Carola; Bonilla, Luis Fabian; Boore, David M.; Rovelli, Antonio; Scotti, Oona

2012-01-01

We propose a site‐classification scheme based on the predominant period of the site, as determined from the average horizontal‐to‐vertical (H/V) spectral ratios of ground motion. Our scheme extends Zhao et al. (2006) classifications by adding two classes, the most important of which is defined by flat H/V ratios with amplitudes less than 2. The proposed classification is investigated by using 5%‐damped response spectra from Italian earthquake records. We select a dataset of 602 three‐component analog and digital recordings from 120 earthquakes recorded at 214 seismic stations within a hypocentral distance of 200 km. Selected events are in the moment‐magnitude range 4.0≤Mw≤6.8 and focal depths from a few kilometers to 46 km. We computed H/V ratios for these data and used them to classify each site into one of six classes. We then investigate the impact of this classification scheme on empirical ground‐motion prediction equations (GMPEs) by comparing its performance with that of the conventional rock/soil classification. Although the adopted approach results in only a small reduction of the overall standard deviation, the use of H/V spectral ratios in site classification does capture the signature of sites with flat frequency‐response, as well as deep and shallow‐soil profiles, characterized by long‐ and short‐period resonance, respectively; in addition, the classification scheme is relatively quick and inexpensive, which is an advantage over schemes based on measurements of shear‐wave velocity.

Site classification of Indian strong motion network using response spectra ratios

NASA Astrophysics Data System (ADS)

Chopra, Sumer; Kumar, Vikas; Choudhury, Pallabee; Yadav, R. B. S.

2018-03-01

In the present study, we tried to classify the Indian strong motion sites spread all over Himalaya and adjoining region, located on varied geological formations, based on response spectral ratio. A total of 90 sites were classified based on 395 strong motion records from 94 earthquakes recorded at these sites. The magnitude of these earthquakes are between 2.3 and 7.7 and the hypocentral distance for most of the cases is less than 50 km. The predominant period obtained from response spectral ratios is used to classify these sites. It was found that the shape and predominant peaks of the spectra at these sites match with those in Japan, Italy, Iran, and at some of the sites in Europe and the same classification scheme can be applied to Indian strong motion network. We found that the earlier schemes based on description of near-surface geology, geomorphology, and topography were not able to capture the effect of sediment thickness. The sites are classified into seven classes (CL-I to CL-VII) with varying predominant periods and ranges as proposed by Alessandro et al. (Bull Seismol Soc Am 102:680-695 2012). The effect of magnitudes and hypocentral distances on the shape and predominant peaks were also studied and found to be very small. The classification scheme is robust and cost-effective and can be used in region-specific attenuation relationships for accounting local site effect.

Weather Satellite Thermal IR Responses Prior to Earthquakes

NASA Technical Reports Server (NTRS)

OConnor, Daniel P.

2005-01-01

A number of observers claim to have seen thermal anomalies prior to earthquakes, but subsequent analysis by others has failed to produce similar findings. What exactly are these anomalies? Might they be useful for earthquake prediction? It is the purpose of this study to determine if thermal anomalies can be found in association with known earthquakes by systematically co-registering weather satellite images at the sub-pixel level and then determining if statistically significant responses occurred prior to the earthquake event. A new set of automatic co-registration procedures was developed for this task to accommodate all properties particular to weather satellite observations taken at night, and it relies on the general condition that the ground cools after sunset. Using these procedures, we can produce a set of temperature-sensitive satellite images for each of five selected earthquakes (Algeria 2003; Bhuj, India 2001; Izmit, Turkey 2001; Kunlun Shan, Tibet 2001; Turkmenistan 2000) and thus more effectively investigate heating trends close to the epicenters a few hours prior to the earthquake events. This study will lay tracks for further work in earthquake prediction and provoke the question of the exact nature of the thermal anomalies.

Strategies for rapid global earthquake impact estimation: the Prompt Assessment of Global Earthquakes for Response (PAGER) system

USGS Publications Warehouse

Jaiswal, Kishor; Wald, D.J.

2013-01-01

This chapter summarizes the state-of-the-art for rapid earthquake impact estimation. It details the needs and challenges associated with quick estimation of earthquake losses following global earthquakes, and provides a brief literature review of various approaches that have been used in the past. With this background, the chapter introduces the operational earthquake loss estimation system developed by the U.S. Geological Survey (USGS) known as PAGER (for Prompt Assessment of Global Earthquakes for Response). It also details some of the ongoing developments of PAGER’s loss estimation models to better supplement the operational empirical models, and to produce value-added web content for a variety of PAGER users.

The 2010 Haiti earthquake response.

PubMed

Raviola, Giuseppe; Severe, Jennifer; Therosme, Tatiana; Oswald, Cate; Belkin, Gary; Eustache, Eddy

2013-09-01

This article presents an overview of the mental health response to the 2010 Haiti earthquake. Discussion includes consideration of complexities that relate to emergency response, mental health and psychosocial response in disasters, long-term planning of systems of care, and the development of safe, effective, and culturally sound mental health services in the Haitian context. This information will be of value to mental health professionals and policy specialists interested in mental health in Haiti, and in the delivery of mental health services in particularly resource-limited contexts in the setting of disasters. Copyright © 2013 Elsevier Inc. All rights reserved.

Possible relationship between Seismic Electric Signals (SES) lead time and earthquake stress drop

PubMed Central

DOLOGLOU, Elizabeth

2008-01-01

Stress drop values for fourteen large earthquakes with MW ≥ 5.4 which occurred in Greece during the period 1983–2007 are available. All these earthquakes were preceded by Seismic Electric Signals (SES). An attempt has been made to investigate possible correlation between their stress drop values and the corresponding SES lead times. For the stress drop, we considered the Brune stress drop, ΔσB, estimated from far field body wave displacement source spectra and ΔσSB derived from the strong motion acceleration response spectra. The results show a relation may exist between Brune stress drop, ΔσB, and lead time which implies that earthquakes with higher stress drop values are preceded by SES with shorter lead time. PMID:18941291

Stochastic modelling of a large subduction interface earthquake in Wellington, New Zealand

NASA Astrophysics Data System (ADS)

Francois-Holden, C.; Zhao, J.

2012-12-01

The Wellington region, home of New Zealand's capital city, is cut by a number of major right-lateral strike slip faults, and is underlain by the currently locked west-dipping subduction interface between the down going Pacific Plate, and the over-riding Australian Plate. A potential cause of significant earthquake loss in the Wellington region is a large magnitude (perhaps 8+) "subduction earthquake" on the Australia-Pacific plate interface, which lies ~23 km beneath Wellington City. "It's Our Fault" is a project involving a comprehensive study of Wellington's earthquake risk. Its objective is to position Wellington city to become more resilient, through an encompassing study of the likelihood of large earthquakes, and the effects and impacts of these earthquakes on humans and the built environment. As part of the "It's Our Fault" project, we are working on estimating ground motions from potential large plate boundary earthquakes. We present the latest results on ground motion simulations in terms of response spectra and acceleration time histories. First we characterise the potential interface rupture area based on previous geodetically-derived estimates interface of slip deficit. Then, we entertain a suitable range of source parameters, including various rupture areas, moment magnitudes, stress drops, slip distributions and rupture propagation directions. Our comprehensive study also includes simulations from historical large world subduction events translated into the New Zealand subduction context, such as the 2003 M8.3 Tokachi-Oki Japan earthquake and the M8.8 2010 Chili earthquake. To model synthetic seismograms and the corresponding response spectra we employed the EXSIM code developed by Atkinson et al. (2009), with a regional attenuation model based on the 3D attenuation model for the lower North-Island which has been developed by Eberhart-Phillips et al. (2005). The resulting rupture scenarios all produce long duration shaking, and peak ground

Report on the 2010 Chilean earthquake and tsunami response

USGS Publications Warehouse

,

2011-01-01

In July 2010, in an effort to reduce future catastrophic natural disaster losses for California, the American Red Cross coordinated and sent a delegation of 20 multidisciplinary experts on earthquake response and recovery to Chile. The primary goal was to understand how the Chilean society and relevant organizations responded to the magnitude 8.8 Maule earthquake that struck the region on February 27, 2010, as well as how an application of these lessons could better prepare California communities, response partners and state emergency partners for a comparable situation. Similarities in building codes, socioeconomic conditions, and broad extent of the strong shaking make the Chilean earthquake a very close analog to the impact of future great earthquakes on California. To withstand and recover from natural and human-caused disasters, it is essential for citizens and communities to work together to anticipate threats, limit effects, and rapidly restore functionality after a crisis. The delegation was hosted by the Chilean Red Cross and received extensive briefings from both national and local Red Cross officials. During nine days in Chile, the delegation also met with officials at the national, regional, and local government levels. Technical briefings were received from the President’s Emergency Committee, emergency managers from ONEMI (comparable to FEMA), structural engineers, a seismologist, hospital administrators, firefighters, and the United Nations team in Chile. Cities visited include Santiago, Talca, Constitución, Concepción, Talcahuano, Tumbes, and Cauquenes. The American Red Cross Multidisciplinary Team consisted of subject matter experts, who carried out special investigations in five Teams on the (1) science and engineering findings, (2) medical services, (3) emergency services, (4) volunteer management, and (5) executive and management issues (see appendix A for a full list of participants and their titles and teams). While developing this

Investigating Lushan Earthquake Victims' Individual Behavior Response and Rescue Organization.

PubMed

Kang, Peng; Lv, Yipeng; Deng, Qiangyu; Liu, Yuan; Zhang, Yi; Liu, Xu; Zhang, Lulu

2017-12-11

Research concerning the impact of earthquake victims' individual behavior and its association with earthquake-related injuries is lacking. This study examined this relationship along with effectiveness of earthquake rescue measures. The six most severely destroyed townships during the Lushan earthquake were examined; 28 villages and three earthquake victims' settlement camp areas were selected as research areas. Inclusion criteria comprised living in Lushan county for a longtime, living in Lushan county during the 2013 Lushan earthquake, and having one's home destroyed. Earthquake victims with an intellectual disability or communication problems were excluded. The earthquake victims (N (number) = 5165, male = 2396) completed a questionnaire (response rate: 94.7%). Among them, 209 were injured (5.61%). Teachers (p < 0.0001, OR (odds ratios) = 3.33) and medical staff (p = 0.001, OR = 4.35) were more vulnerable to the earthquake than were farmers. Individual behavior was directly related to injuries, such as the first reaction after earthquake and fear. There is an obvious connection between earthquake-related injury and individual behavior characteristics. It is strongly suggested that victims receive mental health support from medical practitioners and the government to minimize negative effects. The initial reaction after an earthquake also played a vital role in victims' trauma; therefore, earthquake-related experience and education may prevent injuries. Self-aid and mutual help played key roles in emergency, medical rescue efforts.

Site response for seattle and source parameters of earthquakes in the puget sound region

USGS Publications Warehouse

Frankel, A.; Carver, D.; Cranswick, E.; Meremonte, M.; Bice, T.; Overturf, D.

1999-01-01

We analyzed seismograms from 21 earthquakes (M(L) 2.0-4.9) recorded by digital seismographs we deployed in urban Seatte to determine site response and earthquake stress drops. The seismometers were situated on a wide variety of geologic units, including artificial fill (e.g., Kingdome, Harbor Island), Pleistocene age soils (glacial till and outwash deposits of Seattle's hills), modified land (downtown Seattle, Space Needle), and Tertiary sedimentary rock. Two mainshock-aftershock sequences were recorded: the June 1997 Bremerton sequence (mainshock M(L) 4.9) and the February 1997 South Seattle sequence (mainshock M(L) 3.5), along with other events in the Puget Sound region. We developed a new inversion procedure to estimate site response, source corner frequencies, and seismic moments from the S-wave spectra. This inversion uses corner frequencies determined from spectral ratios of mainshock-aftershock pairs as constraints. The site responses found from the inversion are not relative to the rock site but are relative to an idealized site with a flat frequency response. The response of the rock site is also found from the inversion. The inversion results show high response for the sites on artificial fill, more moderate amplication for most sites on stiff Pleistocene soils or modified land, and low response for the rock site. Some sites display resonances, such as a strong 2-Hz resonance at our site near the Kingdome, which is caused by the surficial layers of fill and younger alluvium. The sites in West Seattle exhibit high amplification, even though they are on relatively stiff soils of glacial outwash. This may be partly caused by basin surface waves produced by conversion of incident S waves. This high response in West Seattle is consistent with damage reports from the 1949 (m(b) 7.1) and 1965 (m(b) 6.5) earthquakes. Stress-drop estimates for the events we recorded were generally low, between 0.4 and 25 bars, although some of the events may have had higher stress

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.

The character of scaling earthquake source spectra for Kamchatka in the 3.5-6.5 magnitude range

NASA Astrophysics Data System (ADS)

Gusev, A. A.; Guseva, E. M.

2017-02-01

The properties of the source spectra of local shallow-focus earthquakes on Kamchatka in the range of magnitudes M w = 3.5-6.5 are studied using 460 records of S-waves obtained at the PET station. The family of average source spectra is constructed; the spectra are used to study the relationship between M w and the key quasi-dimensionless source parameters: stress drop Δσ and apparent stress σa. It is found that the parameter Δσ is almost stable, while σa grows steadily as the magnitude M w increases, indicating that the similarity is violated. It is known that at sufficiently large M w the similarity hypothesis is approximately valid: both parameters Δσ and σa do not show any noticeable magnitude dependence. It has been established that M w ≈ 5.7 is the threshold value of the magnitude when the change in regimes described occurs for the conditions on Kamchatka.

Nonlinear site response in medium magnitude earthquakes near Parkfield, California

USGS Publications Warehouse

Rubinstein, Justin L.

2011-01-01

Careful analysis of strong-motion recordings of 13 medium magnitude earthquakes (3.7 ≤ M ≤ 6.5) in the Parkfield, California, area shows that very modest levels of shaking (approximately 3.5% of the acceleration of gravity) can produce observable changes in site response. Specifically, I observe a drop and subsequent recovery of the resonant frequency at sites that are part of the USGS Parkfield dense seismograph array (UPSAR) and Turkey Flat array. While further work is necessary to fully eliminate other models, given that these frequency shifts correlate with the strength of shaking at the Turkey Flat array and only appear for the strongest shaking levels at UPSAR, the most plausible explanation for them is that they are a result of nonlinear site response. Assuming this to be true, the observation of nonlinear site response in small (M M 6.5 San Simeon earthquake and the 2004 M 6 Parkfield earthquake).

Shaking table test and dynamic response prediction on an earthquake-damaged RC building

NASA Astrophysics Data System (ADS)

Xianguo, Ye; Jiaru, Qian; Kangning, Li

2004-12-01

This paper presents the results from shaking table tests of a one-tenth-scale reinforced concrete (RC) building model. The test model is a protype of a building that was seriously damaged during the 1985 Mexico earthquake. The input ground excitation used during the test was from the records obtained near the site of the prototype building during the 1985 and 1995 Mexico earthquakes. The tests showed that the damage pattern of the test model agreed well with that of the prototype building. Analytical prediction of earthquake response has been conducted for the prototype building using a sophisticated 3-D frame model. The input motion used for the dynamic analysis was the shaking table test measurements with similarity transformation. The comparison of the analytical results and the shaking table test results indicates that the response of the RC building to minor and the moderate earthquakes can be predicated well. However, there is difference between the predication and the actual response to the major earthquake.

2010 Chile Earthquake Aftershock Response

NASA Astrophysics Data System (ADS)

Barientos, Sergio

2010-05-01

The Mw=8.8 earthquake off the coast of Chile on 27 February 2010 is the 5th largest megathrust earthquake ever to be recorded and provides an unprecedented opportunity to advance our understanding of megathrust earthquakes and associated phenomena. The 2010 Chile earthquake ruptured the Concepcion-Constitucion segment of the Nazca/South America plate boundary, south of the Central Chile region and triggered a tsunami along the coast. Following the 2010 earthquake, a very energetic aftershock sequence is being observed in an area that is 600 km along strike from Valparaiso to 150 km south of Concepcion. Within the first three weeks there were over 260 aftershocks with magnitude 5.0 or greater and 18 with magnitude 6.0 or greater (NEIC, USGS). The Concepcion-Constitucion segment lies immediately north of the rupture zone associated with the great magnitude 9.5 Chile earthquake, and south of the 1906 and the 1985 Valparaiso earthquakes. The last great subduction earthquake in the region dates back to the February 1835 event described by Darwin (1871). Since 1835, part of the region was affected in the north by the Talca earthquake in December 1928, interpreted as a shallow dipping thrust event, and by the Chillan earthquake (Mw 7.9, January 1939), a slab-pull intermediate depth earthquake. For the last 30 years, geodetic studies in this area were consistent with a fully coupled elastic loading of the subduction interface at depth; this led to identify the area as a mature seismic gap with potential for an earthquake of magnitude of the order 8.5 or several earthquakes of lesser magnitude. What was less expected was the partial rupturing of the 1985 segment toward north. Today, the 2010 earthquake raises some disturbing questions: Why and how the rupture terminated where it did at the northern end? How did the 2010 earthquake load the adjacent segment to the north and did the 1985 earthquake only partially ruptured the plate interface leaving loaded asperities since

Source and site response study of the 2008 Mount Carmel, Illinois, earthquake

USGS Publications Warehouse

Hartzell, S.; Mendoza, C.

2011-01-01

Two separate inversions are performed using the ground-motion data from the 2008 Mount Carmel, Illinois, earthquake. One uses aftershocks as empirical Green’s functions to determine a finite-fault slip distribution. The second uses mainshock ground-motion spectra to calculate source, path, and site response parameters. The slip inversion reveals a prominent asperity at the hypocenter with an area of approximately 6 km2, moment of 7.0 x 1023 dyn cm (Mw 5.20), and stress drop of about 100 bars. Considering all major and minor slip, the total moment is 1.7 x 1024 dyn cm (Mw=5.45). The rupture velocity is not resolvable due to the small source area. After fixing the geometric spreading, the source, path, and site parameter inversion yields a similar moment of 8.8 x 1023 dyn cm (Mw 5.26) and a corner frequency of 0.89 Hz, which also give a stress drop of approximately 100 bars. Our combined geometric and anelastic attenuation function, Q(f)r-b=1137f0.12r-0.94, fits the regional spectral amplitudes, where the data is more plentiful, as well as previously derived attenuation relationships. Site response spectra show prominent resonant frequencies that correlate with the thickness of Mississippi River sediments and Mississippi embayment deposits. In addition, higher frequency resonance peaks are observed that most likely represent higher mode resonances and resonances from shallower structure.

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

USGS Publications Warehouse

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

2009-01-01

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

Human Trafficking in Nepal: Post-Earthquake Risk and Response.

PubMed

Gyawali, Bishal; Keeling, June; Kallestrup, Per

2017-04-01

As Nepal mourns the 1-year commemoration of the April 2015 earthquake and its aftershocks that killed more than 8500 people and left thousands injured and displaced, other more hidden repercussions of the resultant chaotic environment need attention: the increased risk of human trafficking. Considering that natural disasters provide a milieu for this illicit trade, there is a need for a robust response from stakeholders such as donors, civil society organizations, and government organizations against human trafficking following disasters such as the Nepal earthquake. Responsibility to prevent and fight trafficking should be explicitly included in the mandate of relief and rehabilitation mechanisms set up at the national level to coordinate the disaster relief response, serving to support populations in both rural and urban areas. (Disaster Med Public Health Preparedness. 2017;11:153-154).

Streamflow responses in Chile to megathrust earthquakes in the 20th and 21st centuries

NASA Astrophysics Data System (ADS)

Mohr, Christian; Manga, Michael; Wang, Chi-yuen; Korup, Oliver

2016-04-01

Both coseismic static stress and dynamic stresses associated with seismic waves may cause responses in hydrological systems. Such responses include changes in the water level, hydrochemistry and streamflow discharge. Earthquake effects on hydrological systems provide a means to study the interaction between stress changes and regional hydrology, which is otherwise rarely possible. Chile is a country of frequent and large earthquakes and thus provides abundant opportunities to study such interactions and processes. We analyze streamflow responses in Chile to several megathrust earthquakes, including the 1943 Mw 8.1 Coquimbo, 1950 Mw 8.2 Antofagasta, 1960 Mw 9.5 Valdivia, 1985 Mw 8.0 Valparaiso, 1995 Mw 8.0 Antofagasta, 2010 Mw 8.8 Maule, and the 2014 Mw 8.2 Iquique earthquakes. We use data from 716 stream gauges distributed from the Altiplano in the North to Tierra del Fuego in the South. This network covers the Andes mountain ranges, the central valley, the Coastal Mountain ranges and (mainly in the more southern parts) the Coastal flats. We combine empirical magnitude-distance relationships, machine learning tools, and process-based modeling to characterize responses. We first assess the streamflow anomalies and relate these to topographical, hydro-climatic, geological and earthquake-related (volumetric and dynamic strain) factors using various classifiers. We then apply 1D-groundwater flow modeling to selected catchments in order to test competing hypotheses for the origin of streamflow changes. We show that the co-seismic responses of streamflow mostly involved increasing discharges. We conclude that enhanced vertical permeability can explain most streamflow responses at the regional scale. The total excess water released by a single earthquake, i.e. the Maule earthquake, yielded up to 1 km3. Against the background of megathrust earthquakes frequently hitting Chile, the amount of water released by earthquakes is substantial, particularly for the arid northern

Istanbul Earthquake Early Warning and Rapid Response System

NASA Astrophysics Data System (ADS)

Erdik, M. O.; Fahjan, Y.; Ozel, O.; Alcik, H.; Aydin, M.; Gul, M.

2003-12-01

As part of the preparations for the future earthquake in Istanbul a Rapid Response and Early Warning system in the metropolitan area is in operation. For the Early Warning system ten strong motion stations were installed as close as possible to the fault zone. Continuous on-line data from these stations via digital radio modem provide early warning for potentially disastrous earthquakes. Considering the complexity of fault rupture and the short fault distances involved, a simple and robust Early Warning algorithm, based on the exceedance of specified threshold time domain amplitude levels is implemented. The band-pass filtered accelerations and the cumulative absolute velocity (CAV) are compared with specified threshold levels. When any acceleration or CAV (on any channel) in a given station exceeds specific threshold values it is considered a vote. Whenever we have 2 station votes within selectable time interval, after the first vote, the first alarm is declared. In order to specify the appropriate threshold levels a data set of near field strong ground motions records form Turkey and the world has been analyzed. Correlations among these thresholds in terms of the epicenter distance the magnitude of the earthquake have been studied. The encrypted early warning signals will be communicated to the respective end users by UHF systems through a "service provider" company. The users of the early warning signal will be power and gas companies, nuclear research facilities, critical chemical factories, subway system and several high-rise buildings. Depending on the location of the earthquake (initiation of fault rupture) and the recipient facility the alarm time can be as high as about 8s. For the rapid response system one hundred 18 bit-resolution strong motion accelerometers were placed in quasi-free field locations (basement of small buildings) in the populated areas of the city, within an area of approximately 50x30km, to constitute a network that will enable early

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

USGS Publications Warehouse

Hayes, G.P.; Earle, P.S.; Benz, H.M.; Wald, D.J.; Briggs, R.W.

2011-01-01

This article presents a timeline of NEIC response to a major global earthquake for the first time in a formal journal publication. We outline the key observations of the earthquake made by the NEIC and its partner agencies, discuss how these analyses evolved, and outline when and how this information was released to the public and to other internal and external parties. Our goal in the presentation of this material is to provide a detailed explanation of the issues faced in the response to a rare, giant earthquake. We envisage that the timeline format of this presentation can highlight technical and procedural successes and shortcomings, which may in turn help prompt research by our academic partners and further improvements to our future response efforts. We have shown how NEIC response efforts have significantly improved over the past six years since the great 2004 Sumatra-Andaman earthquake. We are optimistic that the research spawned from this disaster, and the unparalleled dense and diverse data sets that have been recorded, can lead to similar-and necessary-improvements in the future.

A collaborative user-producer assessment of earthquake-response products

USGS Publications Warehouse

Gomberg, Joan; Jakobitz, Allen

2013-01-01

The U.S. Geological Survey (USGS) and the Washington State Emergency Management Division assessed how well USGS earthquake-response products met the needs of emergency managers at county and local levels. Focus-group responses guided development of new products for testing in a regional-scale earthquake exercise. The assessment showed that (1) emergency responders consider most USGS products unnecessary after the first few postearthquake hours because the products are predictors, and responders are quickly immersed in reality; (2) during crises a significant fraction of personnel engaged in emergency response are drawn from many sectors, increasing the breadth of education well beyond emergency management agencies; (3) many emergency personnel do not use maps; and (4) information exchange, archiving, and analyses involve mechanisms and technical capabilities that vary among agencies, so widely used products must be technically versatile and easy to use.

The deadly Morelos-Puebla, Mexico Intraslab Earthquake of 19 September 2017 (Mw7.1): Was the Earthquake Unexpected and Were the Ground Motions and Damage Pattern in Mexico City Abnormal?

NASA Astrophysics Data System (ADS)

Perez-Campos, X.; Singh, S. K.; Arroyo, D.; Cruz-Atienza, V. M.; Ordaz, M.; Hjorleifsdottir, V.; Iglesias, A.

2017-12-01

stress drop. It follows that, for this earthquake, the sites in the city with 1-2s natural period (the transition zone) would be especially vulnerable. Observed damage in the city closely follows this pattern: peak in the response spectra occurs between 1 and 2 s and coincides with sites which have 1 to 2 s natural period and zone of collapsed buildings.

Twitter Seismology: Earthquake Monitoring and Response in a Social World

NASA Astrophysics Data System (ADS)

Bowden, D. C.; Earle, P. S.; Guy, M.; Smoczyk, G.

2011-12-01

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 USGS earthquake response products and the delivery of hazard information. The potential uses of Twitter for earthquake response include broadcasting earthquake alerts, rapidly detecting widely felt events, qualitatively assessing earthquake damage effects, communicating with the public, and participating in post-event collaboration. Several seismic networks and agencies are currently distributing Twitter earthquake alerts including the European-Mediterranean Seismological Centre (@LastQuake), Natural Resources Canada (@CANADAquakes), and the Indonesian meteorological agency (@infogempabmg); the USGS will soon distribute alerts via the @USGSted and @USGSbigquakes Twitter accounts. Beyond broadcasting alerts, the USGS is investigating how to use tweets that originate near the epicenter to detect and characterize shaking events. This is possible because people begin tweeting immediately after feeling an earthquake, and their short narratives and exclamations are available for analysis within 10's of seconds of the origin time. Using five months of tweets that contain the word "earthquake" and its equivalent in other languages, we generate a tweet-frequency time series. The time series clearly shows large peaks correlated with the origin times of widely felt events. To identify possible earthquakes, we use a simple Short-Term-Average / Long-Term-Average algorithm similar to that commonly used to detect seismic phases. As with most auto-detection algorithms, the parameters can be tuned to catch more or less events at the cost of more or less false triggers. When tuned to a moderate sensitivity, the detector found 48 globally-distributed, confirmed seismic events with only 2 false triggers. A space-shuttle landing and "The Great California ShakeOut" caused the false triggers. This number of

Types of hydrogeological response to large-scale explosions and earthquakes

NASA Astrophysics Data System (ADS)

Gorbunova, Ella; Vinogradov, Evgeny; Besedina, Alina; Martynov, Vasilii

2017-04-01

Hydrogeological response to anthropogenic and natural impact indicates massif properties and mode of deformation. We studied uneven-aged aquifers that had been unsealed at the Semipalatinsk testing area (Kazakhstan) and geophysical observatory "Mikhnevo" at the Moscow region (Russia). Data was collected during long-term underground water monitoring that was carried out in 1983-1989 when large-scale underground nuclear explosions were realized. Precise observations of underground water response to distant earthquakes waves passage at GPO "Mikhnevo" have been conducted since 2008. One of the goals of the study was to mark out main types of either dynamic or irreversible spatial-temporal underground water response to large-scale explosions and to compare them with those of earthquakes impact as it had been presented in different papers. As far as nobody really knows hydrogeological processes that occur at the earthquake source it's especially important to analyze experimental data of groundwater level variations that was carried close to epicenter first minutes to hours after explosions. We found that hydrogeodynamic reaction strongly depends on initial geological and hydrogeological conditions as far as on seismic impact parameters. In the near area post-dynamic variations can lead to either excess pressure dome or depression cone forming that results of aquifer drainage due to rock massif fracturing. In the far area explosion effect is comparable with the one of distant earthquake and provides dynamic water level oscillations. Precise monitoring at the "Mikhnevo" area was conducted in the platform conditions far from active faults thus we consider it as a purely calm area far from earthquake sources. Both dynamic and irreversible water level change seem to form power dependence on vertical peak ground displacement velocity due to wave passage. Further research will be aimed at transition close-to-far area to identify a criterion that determines either irreversible

Lg Attenuation and Site Response in the SiChuan basin and the Bayan Har block before the 2008 Ms8.0 Wenchuan Earthquake

NASA Astrophysics Data System (ADS)

Zhu, X.

2017-12-01

On 12 May, 2008, the Sichuan province in China suffered the catastrophic Wenchuan earthquake (MS 8). Prior to the event, a large number of small to moderate earthquakes occurred in the area were recorded at stations of SiChuan Seismic Network (SCSN). The wave data were collected during the years 2006-2008, The Fourier amplitude spectra of Lg wave are used to determine attenuation and site responses. We analyze over 3300 seismograms for Lg-wave propagation from 291 local and regional earthquakes recorded at distances from 100 to 700 km, the earthquakes varied in ML2.0 and 5.7.A joint inversion method estimating attenuation and site responses from seismic spectral ratios is implemented in the study; modeling errors are determined using a delete-j jackknife resampling technique.Variations of the Lg attenuation in a chronological order are studied. The event occurred on the Longmen Shan Fault (LSF), the LSF constitutes boundary betweeb Bayan Har block and eastern. The data are divided into two subgroups based on the seismic ray paths which contained entirely within the SiChuan basin or the Bayan Har block. The waveforms were processed in a frequency range of 1-7 Hz with an interval of 0.2 Hz. On the vertical component, Lg Attenuation in the Bayan Har block are fit by a frequency-dependent function Q(f)=250.2±13.7f0.52±0.03,the SiChuan basin is characterized by function Q(f)=193±23f0.0.81±0.05. The obtained attenuation curves indicate that the spectral amplitudes decay faster in the SiChuan basin than in the Bayan Har block. Site responses from the 48 stations are estimated, the site responses vary among these stations by more than a factor of 10 within the frequency range of interest.The results from the regrouping of data in chronological order show that when the Whenchuan earthquake is approaching, the changes in attenuation occur significantly, but the changes in site responses do not occur.

Fault healing and earthquake spectra from stick slip sequences in the laboratory and on active faults

NASA Astrophysics Data System (ADS)

McLaskey, G. C.; Glaser, S. D.; Thomas, A.; Burgmann, R.

2011-12-01

Repeating earthquake sequences (RES) are thought to occur on isolated patches of a fault that fail in repeated stick-slip fashion. RES enable researchers to study the effect of variations in earthquake recurrence time and the relationship between fault healing and earthquake generation. Fault healing is thought to be the physical process responsible for the 'state' variable in widely used rate- and state-dependent friction equations. We analyze RES created in laboratory stick slip experiments on a direct shear apparatus instrumented with an array of very high frequency (1KHz - 1MHz) displacement sensors. Tests are conducted on the model material polymethylmethacrylate (PMMA). While frictional properties of this glassy polymer can be characterized with the rate- and state- dependent friction laws, the rate of healing in PMMA is higher than room temperature rock. Our experiments show that in addition to a modest increase in fault strength and stress drop with increasing healing time, there are distinct spectral changes in the recorded laboratory earthquakes. Using the impact of a tiny sphere on the surface of the test specimen as a known source calibration function, we are able to remove the instrument and apparatus response from recorded signals so that the source spectrum of the laboratory earthquakes can be accurately estimated. The rupture of a fault that was allowed to heal produces a laboratory earthquake with increased high frequency content compared to one produced by a fault which has had less time to heal. These laboratory results are supported by observations of RES on the Calaveras and San Andreas faults, which show similar spectral changes when recurrence time is perturbed by a nearby large earthquake. Healing is typically attributed to a creep-like relaxation of the material which causes the true area of contact of interacting asperity populations to increase with time in a quasi-logarithmic way. The increase in high frequency seismicity shown here

Planning Matters: Response Operations following the 30 September 2009 Sumatran Earthquake

NASA Astrophysics Data System (ADS)

Comfort, L. K.; Cedillos, V.; Rahayu, H.

2009-12-01

Response operations following the 9/30/2009 West Sumatra earthquake tested extensive planning that had been done in Indonesia since the 26 December 2004 Sumatran Earthquake and Tsunami. After massive destruction in Aceh Province in 2004, the Indonesian National Government revised its national disaster management plans. A key component was to select six cities in Indonesia exposed to significant risk and make a focused investment of resources, planning activities, and public education to reduce risk of major disasters. Padang City was selected for this national “showcase” for disaster preparedness, planning, and response. The question is whether planning improved governmental performance and coordination in practice. There is substantial evidence that disaster preparedness planning and training initiated over the past four years had a positive effect on Padang in terms of disaster risk reduction. The National Disaster Management Agency (BNPB, 10/28/09) reported the following casualties: Padang City: deaths, 383; severe injuries, 431, minor injuries, 771. Province of West Sumatra: deaths, 1209; severe injuries, 67; minor injuries, 1179. These figures contrasted markedly with the estimated losses following the 2004 Earthquake and Tsunami when no training had been done: Banda Aceh, deaths, 118,000; Aceh Province, dead/missing, 236,169 (ID Health Ministry 2/22/05). The 2004 events were more severe, yet the comparable scale of loss was significantly lower in the 9/30/09 earthquake. Three factors contributed to reducing disaster risk in Padang and West Sumatra. First, annual training exercises for tsunami warning and evacuation had been organized by national agencies since 2004. In 2008, all exercises and training activities were placed under the newly established BNPB. The exercise held in Padang in February, 2009 served as an organizing framework for response operations in the 9/30/09 earthquake. Public officers with key responsibilities for emergency operations

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

NASA Astrophysics Data System (ADS)

Xu, Jinghai; An, Jiwen; Nie, Gaozong

2016-04-01

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

Real time drilling mud gas response to small-moderate earthquakes in Wenchuan earthquake Scientific Drilling Hole-1 in SW China

NASA Astrophysics Data System (ADS)

Gong, Zheng; Li, Haibing; Tang, Lijun; Lao, Changling; Zhang, Lei; Li, Li

2017-05-01

We investigated the real time drilling mud gas of the Wenchuan earthquake Fault Scientific Drilling Hole-1 and their responses to 3918 small-moderate aftershocks happened in the Longmenshan fault zone. Gas profiles for Ar, CH4, He, 222Rn, CO2, H2, N2, O2 are obtained. Seismic wave amplitude, energy density and static strain are calculated to evaluate their power of influence to the drilling site. Mud gases two hours before and after each earthquake are carefully analyzed. In total, 25 aftershocks have major mud gas response, the mud gas concentrations vary dramatically immediately or minutes after the earthquakes. Different gas species respond to earthquakes in different manners according to local lithology encountered during the drill. The gas variations are likely controlled by dynamic stress changes, rather than static stress changes. They have the seismic energy density between 10-5 and 1.0 J/m3 whereas the static strain are mostly less than 10-8. We suggest that the limitation of the gas sources and the high hydraulic diffusivity of the newly ruptured fault zone could have inhibited the drilling mud gas behaviors, they are only able to respond to a small portion of the aftershocks. This work is important for the understanding of earthquake related hydrological changes.

Food, water, and fault lines: Remote sensing opportunities for earthquake-response management of agricultural water.

PubMed

Rodriguez, Jenna; Ustin, Susan; Sandoval-Solis, Samuel; O'Geen, Anthony Toby

2016-09-15

Earthquakes often cause destructive and unpredictable changes that can affect local hydrology (e.g. groundwater elevation or reduction) and thus disrupt land uses and human activities. Prolific agricultural regions overlie seismically active areas, emphasizing the importance to improve our understanding and monitoring of hydrologic and agricultural systems following a seismic event. A thorough data collection is necessary for adequate post-earthquake crop management response; however, the large spatial extent of earthquake's impact makes challenging the collection of robust data sets for identifying locations and magnitude of these impacts. Observing hydrologic responses to earthquakes is not a novel concept, yet there is a lack of methods and tools for assessing earthquake's impacts upon the regional hydrology and agricultural systems. The objective of this paper is to describe how remote sensing imagery, methods and tools allow detecting crop responses and damage incurred after earthquakes because a change in the regional hydrology. Many remote sensing datasets are long archived with extensive coverage and with well-documented methods to assess plant-water relations. We thus connect remote sensing of plant water relations to its utility in agriculture using a post-earthquake agrohydrologic remote sensing (PEARS) framework; specifically in agro-hydrologic relationships associated with recent earthquake events that will lead to improved water management. Copyright © 2016 Elsevier B.V. All rights reserved.

Expanding the Delivery of Rapid Earthquake Information and Warnings for Response and Recovery

NASA Astrophysics Data System (ADS)

Blanpied, M. L.; McBride, S.; Hardebeck, J.; Michael, A. J.; van der Elst, N.

2017-12-01

Scientific organizations like the United States Geological Survey (USGS) release information to support effective responses during an earthquake crisis. Information is delivered to the White House, the National Command Center, the Departments of Defense, Homeland Security (including FEMA), Transportation, Energy, and Interior. Other crucial stakeholders include state officials and decision makers, emergency responders, numerous public and private infrastructure management centers (e.g., highways, railroads and pipelines), the media, and the public. To meet the diverse information requirements of these users, rapid earthquake notifications have been developed to be delivered by e-mail and text message, as well as a suite of earthquake information resources such as ShakeMaps, Did You Feel It?, PAGER impact estimates, and data are delivered via the web. The ShakeAlert earthquake early warning system being developed for the U.S. West Coast will identify and characterize an earthquake a few seconds after it begins, estimate the likely intensity of ground shaking, and deliver brief but critically important warnings to people and infrastructure in harm's way. Currently the USGS is also developing a capability to deliver Operational Earthquake Forecasts (OEF). These provide estimates of potential seismic behavior after large earthquakes and during evolving aftershock sequences. Similar work is underway in New Zealand, Japan, and Italy. In the development of OEF forecasts, social science research conducted during these sequences indicates that aftershock forecasts are valued for a variety of reasons, from informing critical response and recovery decisions to psychologically preparing for more earthquakes. New tools will allow users to customize map-based, spatiotemporal forecasts to their specific needs. Hazard curves and other advanced information will also be available. For such authoritative information to be understood and used during the pressures of an earthquake

The Loma Prieta, California, earthquake of October 17, 1989 - Public response: Chapter B in The Loma Prieta, California, earthquake of October 17, 1989: Societal Response (Professional Paper 1553)

USGS Publications Warehouse

Bolton, Patricia A.

1993-01-01

Major earthquakes provide seismologists and engineers an opportunity to examine the performance of the Earth and the man-made structures in response to the forces of the quake. So, too, do they provide social scientists an opportunity to delve into human responses evoked by the ground shaking and its physical consequences. The findings from such research can serve to guide the development and application of programs and practices designed to reduce death, injury, property losses, and social disruption in subsequent earthquakes. This chapter contains findings from studies focused mainly on public response to the Loma Prieta earthquake; that is, on the behavior and perceptions of the general population rather than on the activities of specific organizations or on the impact on procedures or policies. A major feature of several of these studies is that the information was collected from the population throughout the Bay area, not just from persons in the most badly damaged communities or who had suffered the greatest losses. This wide range serves to provide comparisons of behavior for those most directly affected by the earthquake with others who were less directly affected by it but still had to consider it very “close to home.”

Development of the cloud sharing system for residential earthquake responses using smartphones

NASA Astrophysics Data System (ADS)

Shohei, N.; Fujiwara, H.; Azuma, H.; Hao, K. X.

2015-12-01

Earthquake responses at residential depends on its building structure, site amplification, epicenter distance, and etc. Until recently, it was impossible to obtain the individual residential response by conventional seismometer in terms of costs. However, current technology makes it possible with the Micro Electro Mechanical Systems (MEMS) sensors inside mobile terminals like smartphones. We developed the cloud sharing system for residential earthquake response in local community utilizing mobile terminals, such as an iPhone, iPad, iPod touch as a collaboration between NIED and Hakusan Corp. The triggered earthquake acceleration waveforms are recorded at sampling frequencies of 100Hz and stored on their memories once an threshold value was exceeded or ordered information received from the Earthquake Early Warning system. The recorded data is automatically transmitted and archived on the cloud server once the wireless communication is available. Users can easily get the uploaded data by use of a web browser through Internet. The cloud sharing system is designed for residential and only shared in local community internal. Residents can freely add sensors and register information about installation points in each region. And if an earthquake occurs, they can easily view the local distribution of seismic intensities and even analyze waves.To verify this cloud-based seismic wave sharing system, we have performed on site experiments under the cooperation of several local communities, The system and experimental results will be introduced and demonstrated in the presentation.

Modelling Psychological Responses to the Great East Japan Earthquake and Nuclear Incident

PubMed Central

Goodwin, Robin; Takahashi, Masahito; Sun, Shaojing; Gaines, Stanley O.

2012-01-01

The Great East Japan (Tōhoku/Kanto) earthquake of March 2011was followed by a major tsunami and nuclear incident. Several previous studies have suggested a number of psychological responses to such disasters. However, few previous studies have modelled individual differences in the risk perceptions of major events, or the implications of these perceptions for relevant behaviours. We conducted a survey specifically examining responses to the Great Japan earthquake and nuclear incident, with data collected 11–13 weeks following these events. 844 young respondents completed a questionnaire in three regions of Japan; Miyagi (close to the earthquake and leaking nuclear plants), Tokyo/Chiba (approximately 220 km from the nuclear plants), and Western Japan (Yamaguchi and Nagasaki, some 1000 km from the plants). Results indicated significant regional differences in risk perception, with greater concern over earthquake risks in Tokyo than in Miyagi or Western Japan. Structural equation analyses showed that shared normative concerns about earthquake and nuclear risks, conservation values, lack of trust in governmental advice about the nuclear hazard, and poor personal control over the nuclear incident were positively correlated with perceived earthquake and nuclear risks. These risk perceptions further predicted specific outcomes (e.g. modifying homes, avoiding going outside, contemplating leaving Japan). The strength and significance of these pathways varied by region. Mental health and practical implications of these findings are discussed in the light of the continuing uncertainties in Japan following the March 2011 events. PMID:22666380

Future Earth: Reducing Loss By Automating Response to Earthquake Shaking

NASA Astrophysics Data System (ADS)

Allen, R. M.

2014-12-01

Earthquakes pose a significant threat to society in the U.S. and around the world. The risk is easily forgotten given the infrequent recurrence of major damaging events, yet the likelihood of a major earthquake in California in the next 30 years is greater than 99%. As our societal infrastructure becomes ever more interconnected, the potential impacts of these future events are difficult to predict. Yet, the same inter-connected infrastructure also allows us to rapidly detect earthquakes as they begin, and provide seconds, tens or seconds, or a few minutes warning. A demonstration earthquake early warning system is now operating in California and is being expanded to the west coast (www.ShakeAlert.org). In recent earthquakes in the Los Angeles region, alerts were generated that could have provided warning to the vast majority of Los Angelinos who experienced the shaking. Efforts are underway to build a public system. Smartphone technology will be used not only to issue that alerts, but could also be used to collect data, and improve the warnings. The MyShake project at UC Berkeley is currently testing an app that attempts to turn millions of smartphones into earthquake-detectors. As our development of the technology continues, we can anticipate ever-more automated response to earthquake alerts. Already, the BART system in the San Francisco Bay Area automatically stops trains based on the alerts. In the future, elevators will stop, machinery will pause, hazardous materials will be isolated, and self-driving cars will pull-over to the side of the road. In this presentation we will review the current status of the earthquake early warning system in the US. We will illustrate how smartphones can contribute to the system. Finally, we will review applications of the information to reduce future losses.

Tectonic Summaries for Web-served Earthquake Responses, Southeastern North America

USGS Publications Warehouse

Wheeler, Russell L.

2003-01-01

This report documents the rationale and strategy used to write short summaries of the seismicity and tectonic settings of domains in southeastern North America. The summaries are used in automated responses to notable earthquakes that occur anywhere east of the Rocky Mountains in the United States or Canada. Specifically, the report describes the geologic and tectonic information, data sources, criteria, and reasoning used to determine the content and format of the summaries, for the benefit of geologists or seismologists who may someday need to revise the summaries or write others. These tectonic summaries are designed to be automatically posted on the World Wide Web as soon as an earthquake?s epicenter is determined. The summaries are part of a larger collection of summaries that is planned to cover the world.

Phase response curves for models of earthquake fault dynamics

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

Franović, Igor, E-mail: franovic@ipb.ac.rs; Kostić, Srdjan; Perc, Matjaž

We systematically study effects of external perturbations on models describing earthquake fault dynamics. The latter are based on the framework of the Burridge-Knopoff spring-block system, including the cases of a simple mono-block fault, as well as the paradigmatic complex faults made up of two identical or distinct blocks. The blocks exhibit relaxation oscillations, which are representative for the stick-slip behavior typical for earthquake dynamics. Our analysis is carried out by determining the phase response curves of first and second order. For a mono-block fault, we consider the impact of a single and two successive pulse perturbations, further demonstrating how themore » profile of phase response curves depends on the fault parameters. For a homogeneous two-block fault, our focus is on the scenario where each of the blocks is influenced by a single pulse, whereas for heterogeneous faults, we analyze how the response of the system depends on whether the stimulus is applied to the block having a shorter or a longer oscillation period.« less

Use of QuakeSim and UAVSAR for Earthquake Damage Mitigation and Response

NASA Technical Reports Server (NTRS)

Donnellan, A.; Parker, J. W.; Bawden, G.; Hensley, S.

2009-01-01

Spaceborne, airborne, and modeling and simulation techniques are being applied to earthquake risk assessment and response for mitigation from this natural disaster. QuakeSim is a web-based portal for modeling interseismic strain accumulation using paleoseismic and crustal deformation data. The models are used for understanding strain accumulation and release from earthquakes as well as stress transfer to neighboring faults. Simulations of the fault system can be used for understanding the likelihood and patterns of earthquakes as well as the likelihood of large aftershocks from events. UAVSAR is an airborne L-band InSAR system for collecting crustal deformation data. QuakeSim, UAVSAR, and DESDynI (following launch) can be used for monitoring earthquakes, the associated rupture and damage, and postseismic motions for prediction of aftershock locations.

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.

Intra-day response of foreign exchange markets after the Tohoku-Oki earthquake

NASA Astrophysics Data System (ADS)

Nakano, Shuhei; Hirata, Yoshito; Iwayama, Koji; Aihara, Kazuyuki

2015-02-01

Although an economy is influenced by a natural disaster, the market response to the disaster during the first 24 hours is not clearly understood. Here we show that an earthquake quickly causes temporal changes in a foreign exchange market by examining the case of the Tohoku-Oki earthquake. Recurrence plots and statistical change point detection independently show that the United States dollar-Japanese yen market responded to the earthquake activity without delay and with the delay of about 2 minutes, respectively. These findings support that the efficient market hypothesis nearly holds now in the time scale of minutes.

On the Relationship between Fourier and Response Spectra: Implications for the Adjustment of Empirical Ground-Motion Prediction Equations (GMPEs)

NASA Astrophysics Data System (ADS)

Bora, Sanjay; Scherbaum, Frank; Kuehn, Nicolas; Stafford, Peter

2016-04-01

Often, scaling of response spectral amplitudes, (e.g., spectral acceleration) obtained from empirical ground motion prediction equations (GMPEs), with respect to commonly used seismological parameters such as magnitude, distance and site condition is assumed/referred to be representing a similar scaling of Fourier spectral amplitudes. For instance, the distance scaling of response spectral amplitudes is related with the geometrical spreading of seismic waves. Such comparison of scaling of response spectral amplitudes with that of corresponding Fourier spectral amplitudes is motivated by that, the functional forms of response spectral GMPEs are often derived using the concepts borrowed from Fourier spectral modeling of ground motion. As these GMPEs are subsequently calibrated with empirical observations, this may not appear to pose any major problems in the prediction of ground motion for a particular earthquake scenario. However, the assumption that the Fourier spectral concepts persist for response spectra can lead to undesirable consequences when it comes to the adjustment of response spectral GMPEs to represent conditions not covered in the original empirical data set. In this context, a couple of important questions arise, e.g., what are the distinctions and/or similarities between Fourier and response spectra of ground-motions? And, if they are different, then what is the mechanism responsible for such differences and how do adjustments that are made to FAS manifest in response spectra? We explore the relationship between the Fourier and response spectrum of ground motion by using random vibration theory (RVT). With a simple Brune (1970, 1971) source model, RVT-generated acceleration spectra for a fixed magnitude and distance scenario are used. The RVT analyses reveal that the scaling of low oscillator-frequency response spectral ordinates can be treated as being equivalent to the scaling of the corresponding Fourier spectral ordinates. However, the high

E-DECIDER Decision Support Gateway For Earthquake Disaster Response

NASA Astrophysics Data System (ADS)

Glasscoe, M. T.; Stough, T. M.; Parker, J. W.; Burl, M. C.; Donnellan, A.; Blom, R. G.; Pierce, M. E.; Wang, J.; Ma, Y.; Rundle, J. B.; Yoder, M. R.

2013-12-01

Earthquake Data Enhanced Cyber-Infrastructure for Disaster Evaluation and Response (E-DECIDER) is a NASA-funded project developing capabilities for decision-making utilizing remote sensing data and modeling software in order to provide decision support for earthquake disaster management and response. E-DECIDER incorporates earthquake forecasting methodology and geophysical modeling tools developed through NASA's QuakeSim project in order to produce standards-compliant map data products to aid in decision-making following an earthquake. Remote sensing and geodetic data, in conjunction with modeling and forecasting tools, help provide both long-term planning information for disaster management decision makers as well as short-term information following earthquake events (i.e. identifying areas where the greatest deformation and damage has occurred and emergency services may need to be focused). E-DECIDER utilizes a service-based GIS model for its cyber-infrastructure in order to produce standards-compliant products for different user types with multiple service protocols (such as KML, WMS, WFS, and WCS). The goal is to make complex GIS processing and domain-specific analysis tools more accessible to general users through software services as well as provide system sustainability through infrastructure services. The system comprises several components, which include: a GeoServer for thematic mapping and data distribution, a geospatial database for storage and spatial analysis, web service APIs, including simple-to-use REST APIs for complex GIS functionalities, and geoprocessing tools including python scripts to produce standards-compliant data products. These are then served to the E-DECIDER decision support gateway (http://e-decider.org), the E-DECIDER mobile interface, and to the Department of Homeland Security decision support middleware UICDS (Unified Incident Command and Decision Support). The E-DECIDER decision support gateway features a web interface that

Using indirect covariance spectra to identify artifact responses in unsymmetrical indirect covariance calculated spectra.

PubMed

Martin, Gary E; Hilton, Bruce D; Blinov, Kirill A; Williams, Antony J

2008-02-01

Several groups of authors have reported studies in the areas of indirect and unsymmetrical indirect covariance NMR processing methods. Efforts have recently focused on the use of unsymmetrical indirect covariance processing methods to combine various discrete two-dimensional NMR spectra to afford the equivalent of the much less sensitive hyphenated 2D NMR experiments, for example indirect covariance (icv)-heteronuclear single quantum coherence (HSQC)-COSY and icv-HSQC-nuclear Overhauser effect spectroscopy (NOESY). Alternatively, unsymmetrical indirect covariance processing methods can be used to combine multiple heteronuclear 2D spectra to afford icv-13C-15N HSQC-HMBC correlation spectra. We now report the use of responses contained in indirect covariance processed HSQC spectra as a means for the identification of artifacts in both indirect covariance and unsymmetrical indirect covariance processed 2D NMR spectra. Copyright (c) 2007 John Wiley & Sons, Ltd.

Golden Gate Bridge response: a study with low-amplitude data from three earthquakes

USGS Publications Warehouse

Çelebi, Mehmet

2012-01-01

The dynamic response of the Golden Gate Bridge, located north of San Francisco, CA, has been studied previously using ambient vibration data and finite element models. Since permanent seismic instrumentation was installed in 1993, only small earthquakes that originated at distances varying between ~11 to 122 km have been recorded. Nonetheless, these records prompted this study of the response of the bridge to low amplitude shaking caused by three earthquakes. Compared to previous ambient vibration studies, the earthquake response data reveal a slightly higher fundamental frequency (shorter-period) for vertical vibration of the bridge deck center span (~7.7–8.3 s versus 8.2–10.6 s), and a much higher fundamental frequency (shorter period) for the transverse direction of the deck (~11.24–16.3 s versus ~18.2 s). In this study, it is also shown that these two periods are dominant apparent periods representing interaction between tower, cable, and deck.

The 2015 Nepal Earthquake(s): Lessons Learned From the Disability and Rehabilitation Sector's Preparation for, and Response to, Natural Disasters.

PubMed

Landry, Michel D; Sheppard, Phillip S; Leung, Kit; Retis, Chiara; Salvador, Edwin C; Raman, Sudha R

2016-11-01

The frequency of natural disasters appears to be mounting at an alarming rate, and the degree to which people are surviving such traumatic events also is increasing. Postdisaster survival often triggers increases in population and individual disability-related outcomes in the form of impairments, activity limitations, and participation restrictions, all of which have an important impact on the individual, his or her family, and their community. The increase in postdisaster disability-related outcomes has provided a rationale for the increased role of the disability and rehabilitation sector's involvement in emergency response, including physical therapists. A recent major earthquake that has drawn the world's attention occurred in the spring of 2015 in Nepal. The response of the local and international communities was large and significant, and although the collection of complex health and disability issues have yet to be fully resolved, there has been a series of important lessons learned from the 2015 Nepal earthquake(s). This perspective article outlines lessons learned from Nepal that can be applied to future disasters to reduce overall disability-related outcomes and more fully integrate rehabilitation in preparation and planning. First, information is presented on disasters in general, and then information is presented that focuses on the earthquake(s) in Nepal. Next, field experience in Nepal before, during, and after the earthquake is described, and actions that can and should be adopted prior to disasters as part of disability preparedness planning are examined. Then, the emerging roles of rehabilitation providers such as physical therapists during the immediate and postdisaster recovery phases are discussed. Finally, approaches are suggested that can be adopted to "build back better" for, and with, people with disabilities in postdisaster settings such as Nepal. © 2016 American Physical Therapy Association.

Lessons from the Chilean earthquake: how a human rights framework facilitates disaster response.

PubMed

Arbour, MaryCatherine; Murray, Kara; Arriet, Felipe; Moraga, Cecilia; Vega, Miguel Cordero

2011-07-14

The earthquake of 2010 in Chile holds important lessons about how a rights-based public health system can guide disaster response to protect vulnerable populations. This article tells the story of Chile Grows With You (Chile Crece Contigo), an intersectoral system created three years before the earthquake for protection of child rights and development, and its role in the disaster response. The creation of Chile Grows With You with an explicit rights-oriented mandate established intersectoral mechanisms, relationships, and common understanding between governmental groups at the national and local levels. After the earthquake, Chile Grows With You organized its activities according to its founding principles: it provided universal access and support for all Chilean children, with special attention and services for those at greatest risk. This tiered approach involved public health and education materials for all children and families; epidemiologic data for local planners about children in their municipalities at-risk before the earthquake; and an instrument developed to assist in the assessment and intervention of children put at risk by the earthquake. This disaster response illustrates how a rights-based framework defined and operationalized in times of stability facilitated organization, prioritization, and sustained action to protect and support children and families in the acute aftermath of the earthquake, despite a change in government from a left-wing to a right-wing president, and into the early recovery period. Copyright © 2011 Arbour, Murray, Arriet, Moraga, and Vega. This is an open access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0/), which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original author and source are credited.

Earthquake impact scale

USGS Publications Warehouse

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

2011-01-01

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

Facilitators and obstacles in pre-hospital medical response to earthquakes: a qualitative study.

PubMed

Djalali, Ahmadreza; Khankeh, Hamidreza; Öhlén, Gunnar; Castrén, Maaret; Kurland, Lisa

2011-05-16

Earthquakes are renowned as being amongst the most dangerous and destructive types of natural disasters. Iran, a developing country in Asia, is prone to earthquakes and is ranked as one of the most vulnerable countries in the world in this respect. The medical response in disasters is accompanied by managerial, logistic, technical, and medical challenges being also the case in the Bam earthquake in Iran. Our objective was to explore the medical response to the Bam earthquake with specific emphasis on pre-hospital medical management during the first days. The study was performed in 2008; an interview based qualitative study using content analysis. We conducted nineteen interviews with experts and managers responsible for responding to the Bam earthquake, including pre-hospital emergency medical services, the Red Crescent, and Universities of Medical Sciences. The selection of participants was determined by using a purposeful sampling method. Sample size was given by data saturation. The pre-hospital medical service was divided into three categories; triage, emergency medical care and transportation, each category in turn was identified into facilitators and obstacles. The obstacles identified were absence of a structured disaster plan, absence of standardized medical teams, and shortage of resources. The army and skilled medical volunteers were identified as facilitators. The most compelling, and at the same time amenable obstacle, was the lack of a disaster management plan. It was evident that implementing a comprehensive plan would not only save lives but decrease suffering and enable an effective praxis of the available resources at pre-hospital and hospital levels.

Facilitators and obstacles in pre-hospital medical response to earthquakes: a qualitative study

PubMed Central

2011-01-01

Background Earthquakes are renowned as being amongst the most dangerous and destructive types of natural disasters. Iran, a developing country in Asia, is prone to earthquakes and is ranked as one of the most vulnerable countries in the world in this respect. The medical response in disasters is accompanied by managerial, logistic, technical, and medical challenges being also the case in the Bam earthquake in Iran. Our objective was to explore the medical response to the Bam earthquake with specific emphasis on pre-hospital medical management during the first days. Methods The study was performed in 2008; an interview based qualitative study using content analysis. We conducted nineteen interviews with experts and managers responsible for responding to the Bam earthquake, including pre-hospital emergency medical services, the Red Crescent, and Universities of Medical Sciences. The selection of participants was determined by using a purposeful sampling method. Sample size was given by data saturation. Results The pre-hospital medical service was divided into three categories; triage, emergency medical care and transportation, each category in turn was identified into facilitators and obstacles. The obstacles identified were absence of a structured disaster plan, absence of standardized medical teams, and shortage of resources. The army and skilled medical volunteers were identified as facilitators. Conclusions The most compelling, and at the same time amenable obstacle, was the lack of a disaster management plan. It was evident that implementing a comprehensive plan would not only save lives but decrease suffering and enable an effective praxis of the available resources at pre-hospital and hospital levels. PMID:21575233

NGA-West2 Empirical Fourier Model for Active Crustal Regions to Generate Regionally Adjustable Response Spectra

NASA Astrophysics Data System (ADS)

Bora, S. S.; Cotton, F.; Scherbaum, F.; Kuehn, N. M.

2016-12-01

Adjustment of median ground motion prediction equations (GMPEs) from data-rich (host) regions to data-poor regions (target) is one of major challenges that remains with the current practice of engineering seismology and seismic hazard analysis. Fourier spectral representation of ground motion provides a solution to address the problem of adjustment that is physically transparent and consistent with the concepts of linear system theory. Also, it provides a direct interface to appreciate the physically expected behavior of seismological parameters on ground motion. In the present study, we derive an empirical Fourier model for computing regionally adjustable response spectral ordinates based on random vibration theory (RVT) from shallow crustal earthquakes in active tectonic regions, following the approach of Bora et al. (2014, 2015). , For this purpose, we use an expanded NGA-West2 database with M 3.2—7.9 earthquakes at distances ranging from 0 to 300 km. A mixed-effects regression technique is employed to further explore various components of variability. The NGA-West2 database expanded over a wide magnitude range provides a better understanding (and constraint) of source scaling of ground motion. The large global volume of the database also allows investigating regional patterns in distance-dependent attenuation (i.e., geometrical spreading and inelastic attenuation) of ground motion as well as in the source parameters (e.g., magnitude and stress drop). Furthermore, event-wise variability and its correlation with stress parameter are investigated. Finally, application of the derived Fourier model in generating adjustable response spectra will be shown.

Near-real-time Earthquake Notification and Response in the Classroom: Exploiting the Teachable Moment

NASA Astrophysics Data System (ADS)

Furlong, K. P.; Whitlock, J. S.; Benz, H. M.

2002-12-01

Earthquakes occur globally, on a regular but (as yet) non-predictable basis, and their effects are both dramatic and often devastating. Additionally they serve as a primary tool to image the earth and define the active processes that drive tectonics. As a result, earthquakes can be an extremely effective tool for helping students to learn about active earth processes, natural hazards, and the myriad of issues that arise with non-predictable but potentially devastating natural events. We have developed and implemented a real-time earthquake alert system (EAS) built on the USGS Earthworm system to bring earthquakes into the classroom. Through our EAS, students in our General Education class on Natural Hazards (Earth101 - Natural Disasters: Hollywood vs. Reality) participate in earthquake response activities in ways similar to earthquake hazard professionals - they become part of the response to the event. Our implementation of the Earthworm system allows our students to be paged via cell-phone text messaging (Yes, we provide cell phones to the 'duty seismologists'), and they respond to those pages as appropriate for their role. A parallel web server is maintained that provides the earthquake details (location maps, waveforms etc.) and students produce time-critical output such as news releases, analyses of earthquake trends in the region, and reports detailing implications of the events. Since this is a course targeted at non-science majors, we encourage that they bring their own expertise into the analyses. For example, business of economic majors may investigate the economic impacts of an earthquake, secondary education majors may work on teaching modules based on the information they gather etc. Since the students know that they are responding to real events they develop ownership of the information they gather and they recognize the value of real-time response. Our educational goals in developing this system include: (1) helping students develop a sense of the

Incorporation of Dynamic SSI Effects in the Design Response Spectra

NASA Astrophysics Data System (ADS)

Manjula, N. K.; Pillai, T. M. Madhavan; Nagarajan, Praveen; Reshma, K. K.

2018-05-01

Many studies in the past on dynamic soil-structure interactions have revealed the detrimental and advantageous effects of soil flexibility. Based on such studies, the design response spectra of international seismic codes are being improved worldwide. The improvements required for the short period range of the design response spectra in the Indian seismic code (IS 1893:2002) are presented in this paper. As the recent code revisions has not incorporated the short period amplifications, proposals given in this paper are equally applicable for the latest code also (IS 1893:2016). Analyses of single degree of freedom systems are performed to predict the required improvements. The proposed modifications to the constant acceleration portion of the spectra are evaluated with respect to the current design spectra in Eurocode 8.

Effect of shales on tidal response of water level to large earthquakes

NASA Astrophysics Data System (ADS)

Zhang, Y.; Wang, C. Y.; Fu, L. Y.

2017-12-01

Tidal response of water level in wells has been widely used to study properties of aquifers and, in particular, the response of groundwater to earthquakes. The affect of lithology on such response has not received deserved attention. Using data from selected wells in the intermediate and far fields of the 2008 Mw 7.9 Wenchuan and the 2011 Mw 9.1 Tohoku earthquakes, we examine how the presence of shales affects the tidal response of water level. Three categories of responses are recognized: horizontal flow, vertical flow and combined horizontal and vertical flow, with most wells with shales in the last category. We found that wells with shales are significantly influenced by fractures, leading semi-confined condition and vertical drainage, poorer well bore storage and decreased or unchanged co-seismic phase shifts. We also found a strong correlation between the shale content in the aquifer and the amplitude of tidal response, with higher shale content correlated with lower amplitude response, which we attribute to the compact structure (low porosity/low permeability) of shales.

Earthquake response of heavily damaged historical masonry mosques after restoration

NASA Astrophysics Data System (ADS)

Altunışık, Ahmet Can; Fuat Genç, Ali

2017-10-01

Restoration works have been accelerated substantially in Turkey in the last decade. Many historical buildings, mosques, minaret, bridges, towers and structures have been restored. With these restorations an important issue arises, namely how restoration work affects the structure. For this reason, we aimed to investigate the restoration effect on the earthquake response of a historical masonry mosque considering the openings on the masonry dome. For this purpose, we used the Hüsrev Pasha Mosque, which is located in the Ortakapı district in the old city of Van, Turkey. The region of Van is in an active seismic zone; therefore, earthquake analyses were performed in this study. Firstly a finite element model of the mosque was constructed considering the restoration drawings and 16 window openings on the dome. Then model was constructed with eight window openings. Structural analyses were performed under dead load and earthquake load, and the mode superposition method was used in analyses. Maximum displacements, maximum-minimum principal stresses and shear stresses are given with contours diagrams. The results are analyzed according to Turkish Earthquake Code (TEC, 2007) and compared between 8 and 16 window openings cases. The results show that reduction of the window openings affected the structural behavior of the mosque positively.

USGS GNSS Applications to Earthquake Disaster Response and Hazard Mitigation

NASA Astrophysics Data System (ADS)

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

2015-12-01

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

Method meets application: on the use of earthquake scenarios in community-based disaster preparedness and response

NASA Astrophysics Data System (ADS)

Sargeant, S.; Sorensen, M. B.

2011-12-01

More than 50% of the world's population now live in urban areas. In less developed countries, future urban population increase will be due to natural population growth and rural-to-urban migration. As urban growth continues, the vulnerability of those living in these areas is also increasing. This presents a wide variety of challenges for humanitarian organisations that often have more experience of disaster response in rural settings rather than planning for large urban disasters. The 2010 Haiti earthquake highlighted the vulnerability of these organisations and the communities that they seek to support. To meet this challenge, a key consideration is how scientific information can support the humanitarian sector and their working practices. Here we review the current state of earthquake scenario modelling practice, with special focus on scenarios to be used in disaster response and response planning, and present an evaluation of how the field looks set to evolve. We also review current good practice and lessons learned from previous earthquakes with respect to planning for and responding to earthquakes in urban settings in the humanitarian sector, identifying key sectoral priorities. We then investigate the interface between these two areas to investigate the use of earthquake scenarios in disaster response planning and identify potential challenges both with respect to development of scientific models and their application on the ground.

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.

Silicon Drift Detector response function for PIXE spectra fitting

NASA Astrophysics Data System (ADS)

Calzolai, G.; Tapinassi, S.; Chiari, M.; Giannoni, M.; Nava, S.; Pazzi, G.; Lucarelli, F.

2018-02-01

The correct determination of the X-ray peak areas in PIXE spectra by fitting with a computer program depends crucially on accurate parameterization of the detector peak response function. In the Guelph PIXE software package, GUPIXWin, one of the most used PIXE spectra analysis code, the response of a semiconductor detector to monochromatic X-ray radiation is described by a linear combination of several analytical functions: a Gaussian profile for the X-ray line itself, and additional tail contributions (exponential tails and step functions) on the low-energy side of the X-ray line to describe incomplete charge collection effects. The literature on the spectral response of silicon X-ray detectors for PIXE applications is rather scarce, in particular data for Silicon Drift Detectors (SDD) and for a large range of X-ray energies are missing. Using a set of analytical functions, the SDD response functions were satisfactorily reproduced for the X-ray energy range 1-15 keV. The behaviour of the parameters involved in the SDD tailing functions with X-ray energy is described by simple polynomial functions, which permit an easy implementation in PIXE spectra fitting codes.

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.

The role of complex site and basin response in Wellington city, New Zealand, during the 2016 Mw 7.8 Kaikōura earthquake and other recent earthquake sequences.

NASA Astrophysics Data System (ADS)

Kaiser, A. E.; McVerry, G.; Wotherspoon, L.; Bradley, B.; Gerstenberger, M.; Benites, R. A.; Bruce, Z.; Bourguignon, S.; Giallini, S.; Hill, M.

2017-12-01

We present analysis of ground motion and complex amplification characteristics in Wellington during recent earthquake sequences and an overview of the 3D basin characterization and ongoing work to update site parameters for seismic design. Significant damage was observed in central Wellington, New Zealand's capital city, following the 2016 Mw7.8 Kaikōura earthquake. Damage was concentrated in mid-rise structures (5 - 15 storeys) and was clearly exacerbated by the particular characteristics of ground motion and the presence of basin effects. Due to the distance of the source (50 - 60km) from the central city, peak ground accelerations were moderate (up to 0.28g) and well within ultimate limit state (ULS) design levels. However, spectral accelerations within the 1 -2 s period range, exceeded 1 in 500 year design level spectra (ULS) in deeper parts of the basin. Amplification with respect to rock at these locations reached factors of up to 7, and was also observed with factors up to at least three across all central city soil recording sites. The ground motions in Wellington were the strongest recorded in the modern era of instrumentation. While similar amplification was observed during the 2013 Mw 6.6 Cook Strait and Grassmere earthquakes, which struck close to the termination of the Kaikōura earthquake rupture, these sources were not sufficiently large to excite significant long-period motions. However, other M7.2+ sources in the region that dominate the seismic hazard, e.g. Wellington Fault, Hikurangi subduction interface and other large proximal crustal faults, are also potentially capable of exciting significant long-period basin response in Wellington. These observations and the expectation of ongoing heightened seismicity have prompted re-evaluation of the current seismic demand levels. Additional field campaigns have also been undertaken to update geotechnical properties and the 3D basin model, in order to inform ongoing research and seismic design practice.

Poroelastic response to megathrust earthquakes: A look at the 2012 Mw 7.6 Costa Rican event

NASA Astrophysics Data System (ADS)

McCormack, K. A.; Hesse, M. A.

2017-12-01

Following an earthquake, surface deformation is influenced by a myriad of post-seismic processes including after-slip, poroelastic and viscoelastic relaxation. Geodetic measurements record the combined result of all these processes, which makes studying the effects of any single process difficult. To constrain the poroelastic component of post-seismic deformation, we model the subsurface hydrologic response to the Mw 7.6 subduction zone earthquake beneath the Nicoya peninsula on September 5, 2012. The regional-scale poroelastic model of the overlying plate integrates seismologic, geodetic and hydrologic data sets to predict the post-seismic poroelastic response. Following the earthquake, continuous surface deformation was observed with high-rate GPS monitoring directly above the rupture zone. By modeling the time-dependent deformation associated with poroelastic relaxation, we can begin to remove the contribution of groundwater flow from the observed geodetic signal. For this study we used both 2D and 3D numerical models. In 2D we investigate more general trends in the poroelastic response of a subduction zone earthquake. In 3D we model the poroelastic response to the 2012 Nicoya event using a fixed set of best fit parameters and the real earthquake slip data. The slip distribution of 2012 event is obtained by inverting the co-seismic surface GPS displacements for fault slip. The 2D model shows that thrust earthquakes with a rupture width less than a third of their depth produce complex multi-lobed pressure perturbations in the shallow subsurface. In the 3D model, the small width to depth ratio of the Nicoya rupture leads to a multi-lobed initial pore pressure distribution. This creates complex groundwater flow patterns, non-monotonic variations in well head and surface deformation, and poroelastic relaxation over multiple, distinct time scales. Different timescales arise because the earthquake causes pressure perturbations with different wavelengths. In the

E-DECIDER: Using Earth Science Data and Modeling Tools to Develop Decision Support for Earthquake Disaster Response

NASA Astrophysics Data System (ADS)

Glasscoe, Margaret T.; Wang, Jun; Pierce, Marlon E.; Yoder, Mark R.; Parker, Jay W.; Burl, Michael C.; Stough, Timothy M.; Granat, Robert A.; Donnellan, Andrea; Rundle, John B.; Ma, Yu; Bawden, Gerald W.; Yuen, Karen

2015-08-01

Earthquake Data Enhanced Cyber-Infrastructure for Disaster Evaluation and Response (E-DECIDER) is a NASA-funded project developing new capabilities for decision making utilizing remote sensing data and modeling software to provide decision support for earthquake disaster management and response. E-DECIDER incorporates the earthquake forecasting methodology and geophysical modeling tools developed through NASA's QuakeSim project. Remote sensing and geodetic data, in conjunction with modeling and forecasting tools allows us to provide both long-term planning information for disaster management decision makers as well as short-term information following earthquake events (i.e. identifying areas where the greatest deformation and damage has occurred and emergency services may need to be focused). This in turn is delivered through standards-compliant web services for desktop and hand-held devices.

Responses of buried corrugated metal pipes to earthquakes

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

Davis, C.A.; Bardet, J.P.

2000-01-01

This study describes the results of field investigations and analyses carried out on 61 corrugated metal pipes (CMP) that were shaken by the 1994 Northridge earthquake. These CMPs, which include 29 small-diameter (below 107 cm) CMPs and 32 large-diameter (above 107 cm) CMPs, are located within a 10 km{sup 2} area encompassing the Van Normal Complex in the Northern San Fernando Valley, in Los Angeles, California. During the Northridge earthquake, ground movements were extensively recorded within the study area. Twenty-eight of the small-diameter CMPs performed well while the 32 large-diameter CMPs underwent performances ranging from no damage to complete collapse.more » The main cause of damage to the large-diameter CMPs was found to be the large ground strains. Based on this unprecedented data set, the factors controlling the seismic performance of the 32 large-diameter CMPs were identified and framed into a pseudostatic analysis method for evaluating the response of large diameter flexible underground pipes subjected to ground strain. The proposed analysis, which is applicable to transient and permanent strains, is capable of describing the observed performance of large-diameter CMPs during the 1994 Northridge earthquake. It indicates that peak ground velocity is a more reliable parameter for analyzing pipe damage than is peak ground acceleration. Results of this field investigation and analysis are useful for the seismic design and strengthening of flexible buried conduits.« less

Immediate behavioural responses to earthquakes in Christchurch, New Zealand, and Hitachi, Japan.

PubMed

Lindell, Michael K; Prater, Carla S; Wu, Hao Che; Huang, Shih-Kai; Johnston, David M; Becker, Julia S; Shiroshita, Hideyuki

2016-01-01

This study examines people's immediate responses to earthquakes in Christchurch, New Zealand, and Hitachi, Japan. Data collected from 257 respondents in Christchurch and 332 respondents in Hitachi revealed notable similarities between the two cities in people's emotional reactions, risk perceptions, and immediate protective actions during the events. Respondents' physical, household, and social contexts were quite similar, but Hitachi residents reported somewhat higher levels of emotional reaction and risk perception than did Christchurch residents. Contrary to the recommendations of emergency officials, the most frequent response of residents in both cities was to freeze. Christchurch residents were more likely than Hitachi residents to drop to the ground and take cover, whereas Hitachi residents were more likely than Christchurch residents to evacuate immediately the building in which they were situated. There were relatively small correlations between immediate behavioural responses and demographic characteristics, earthquake experience, and physical, social, or household context. © 2016 The Author(s). Disasters © Overseas Development Institute, 2016.

Three-dimensional ground-motion simulations of earthquakes for the Hanford area, Washington

USGS Publications Warehouse

Frankel, Arthur; Thorne, Paul; Rohay, Alan

2014-01-01

This report describes the results of ground-motion simulations of earthquakes using three-dimensional (3D) and one-dimensional (1D) crustal models conducted for the probabilistic seismic hazard assessment (PSHA) of the Hanford facility, Washington, under the Senior Seismic Hazard Analysis Committee (SSHAC) guidelines. The first portion of this report demonstrates that the 3D seismic velocity model for the area produces synthetic seismograms with characteristics (spectral response values, duration) that better match those of the observed recordings of local earthquakes, compared to a 1D model with horizontal layers. The second part of the report compares the response spectra of synthetics from 3D and 1D models for moment magnitude (M) 6.6–6.8 earthquakes on three nearby faults and for a dipping plane wave source meant to approximate regional S-waves from a Cascadia great earthquake. The 1D models are specific to each site used for the PSHA. The use of the 3D model produces spectral response accelerations at periods of 0.5–2.0 seconds as much as a factor of 4.5 greater than those from the 1D models for the crustal fault sources. The spectral accelerations of the 3D synthetics for the Cascadia plane-wave source are as much as a factor of 9 greater than those from the 1D models. The differences between the spectral accelerations for the 3D and 1D models are most pronounced for sites with thicker supra-basalt sediments and for stations with earthquakes on the Rattlesnake Hills fault and for the Cascadia plane-wave source.

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

USGS Publications Warehouse

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

2008-01-01

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

The Technical Efficiency of Earthquake Medical Rapid Response Teams Following Disasters: The Case of the 2010 Yushu Earthquake in China.

PubMed

Liu, Xu; Tang, Bihan; Yang, Hongyang; Liu, Yuan; Xue, Chen; Zhang, Lulu

2015-12-04

Performance assessments of earthquake medical rapid response teams (EMRRTs), particularly the first responders deployed to the hardest hit areas following major earthquakes, should consider efficient and effective use of resources. This study assesses the daily technical efficiency of EMRRTs in the emergency period immediately following the 2010 Yushu earthquake in China. Data on EMRRTs were obtained from official daily reports of the general headquarters for Yushu earthquake relief, the emergency office of the National Ministry of Health, and the Health Department of Qinghai Province, for a sample of data on 15 EMRRTs over 62 days. Data envelopment analysis was used to examine the technical efficiency in a constant returns to scale model, a variable returns to scale model, and the scale efficiency of EMRRTs. Tobit regression was applied to analyze the effects of corresponding influencing factors. The average technical efficiency scores under constant returns to scale, variable returns to scale, and the scale efficiency scores of the 62 units of analysis were 77.95%, 89.00%, and 87.47%, respectively. The staff-to-bed ratio was significantly related to global technical efficiency. The date of rescue was significantly related to pure technical efficiency. The type of institution to which an EMRRT belonged and the staff-to-bed ratio were significantly related to scale efficiency. This study provides evidence that supports improvements to EMRRT efficiency and serves as a reference for earthquake emergency medical rapid assistance leaders and teams.

Response of two identical seven-story structures to the San Fernando earthquake of February 9, 1971

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

Freeman, S.A.; Honda, K.K.

1973-10-01

The results of the structural dynamic investigation of two sevenstory reinforced concrete frame structures are presented here. The structures are both Holiday Inn rnotor hotels that are essentially identical: one is locrted about 13 miles and the other about 26 miles from the epicenter of the February 9, 1971, San Fernando earthquake. Appreciable nonstructural damage as well as some structural damage was observed. Strong-motion seismic records were obtained for the roof, intermediate story, and ground floor of each structure. The analyses are based on data from the structural drawings, architectural drawings, photographs, engineering reports, and seisrnogram records obtained before, during,more » and after the San Fernando earthquake. Both structures experienced motion well beyond the limits of the building code design criteria. A change in fundamental period was observed for each structure after several seconds of response to the earthquake, which indicated nonlinear response. The analyses indicated that the elastic capacity of some structural members was exceeded. Idealized linear models were constructed to approximate response at various time segments. A method for approximating the nonlinear response of each structure is presented. The effects of nonstructural elements, yielding beams, and column capacities are illustrated. Comparisons of the two buildings are made for ductility factors, dynarnic response characteristics, and damage. Conclusions are drawn concerning the effects of the earthquake on the structures and the future capacities of the structures. (auth)« less

Monitoring reservoir response to earthquakes and fluid extraction, Salton Sea geothermal field, California

PubMed Central

Taira, Taka’aki; Nayak, Avinash; Brenguier, Florent; Manga, Michael

2018-01-01

Continuous monitoring of in situ reservoir responses to stress transients provides insights into the evolution of geothermal reservoirs. By exploiting the stress dependence of seismic velocity changes, we investigate the temporal evolution of the reservoir stress state of the Salton Sea geothermal field (SSGF), California. We find that the SSGF experienced a number of sudden velocity reductions (~0.035 to 0.25%) that are most likely caused by openings of fractures due to dynamic stress transients (as small as 0.08 MPa and up to 0.45 MPa) from local and regional earthquakes. Depths of velocity changes are estimated to be about 0.5 to 1.5 km, similar to the depths of the injection and production wells. We derive an empirical in situ stress sensitivity of seismic velocity changes by relating velocity changes to dynamic stresses. We also observe systematic velocity reductions (0.04 to 0.05%) during earthquake swarms in mid-November 2009 and late-December 2010. On the basis of volumetric static and dynamic stress changes, the expected velocity reductions from the largest earthquakes with magnitude ranging from 3 to 4 in these swarms are less than 0.02%, which suggests that these earthquakes are likely not responsible for the velocity changes observed during the swarms. Instead, we argue that velocity reductions may have been induced by poroelastic opening of fractures due to aseismic deformation. We also observe a long-term velocity increase (~0.04%/year) that is most likely due to poroelastic contraction caused by the geothermal production. Our observations demonstrate that seismic interferometry provides insights into in situ reservoir response to stress changes. PMID:29326977

Monitoring reservoir response to earthquakes and fluid extraction, Salton Sea geothermal field, California.

PubMed

Taira, Taka'aki; Nayak, Avinash; Brenguier, Florent; Manga, Michael

2018-01-01

Continuous monitoring of in situ reservoir responses to stress transients provides insights into the evolution of geothermal reservoirs. By exploiting the stress dependence of seismic velocity changes, we investigate the temporal evolution of the reservoir stress state of the Salton Sea geothermal field (SSGF), California. We find that the SSGF experienced a number of sudden velocity reductions (~0.035 to 0.25%) that are most likely caused by openings of fractures due to dynamic stress transients (as small as 0.08 MPa and up to 0.45 MPa) from local and regional earthquakes. Depths of velocity changes are estimated to be about 0.5 to 1.5 km, similar to the depths of the injection and production wells. We derive an empirical in situ stress sensitivity of seismic velocity changes by relating velocity changes to dynamic stresses. We also observe systematic velocity reductions (0.04 to 0.05%) during earthquake swarms in mid-November 2009 and late-December 2010. On the basis of volumetric static and dynamic stress changes, the expected velocity reductions from the largest earthquakes with magnitude ranging from 3 to 4 in these swarms are less than 0.02%, which suggests that these earthquakes are likely not responsible for the velocity changes observed during the swarms. Instead, we argue that velocity reductions may have been induced by poroelastic opening of fractures due to aseismic deformation. We also observe a long-term velocity increase (~0.04%/year) that is most likely due to poroelastic contraction caused by the geothermal production. Our observations demonstrate that seismic interferometry provides insights into in situ reservoir response to stress changes.

It's Our Fault: better defining earthquake risk in Wellington, New Zealand

NASA Astrophysics Data System (ADS)

Van Dissen, R.; Brackley, H. L.; Francois-Holden, C.

2012-12-01

increasing the region's resilience to earthquakes. We present latest results on ground motion simulations for large plate interface earthquakes under Wellington in terms of response spectra and acceleration time histories. We derive realistic broadband accelerograms based on a stochastic modelling technique. First we characterise the potential interface rupture area based on previous geodetically-derived estimates interface of slip deficit. Then, we entertain a suitable range of source parameters, including various rupture areas, moment magnitudes, stress drops, slip distributions and rupture propagation directions. The resulting rupture scenarios all produce long duration shaking, and peak ground accelerations that, typically, range between 0.2-0.7 g in Wellington city. Many of these scenarios also produce long period motions that are currently not captured by the current NZ design spectra.

Development of the U.S. Geological Survey's PAGER system (Prompt Assessment of Global Earthquakes for Response)

USGS Publications Warehouse

Wald, D.J.; Earle, P.S.; Allen, T.I.; Jaiswal, K.; Porter, K.; Hearne, M.

2008-01-01

The Prompt Assessment of Global Earthquakes for Response (PAGER) System plays a primary alerting role for global earthquake disasters as part of the U.S. Geological Survey’s (USGS) response protocol. We provide an overview of the PAGER system, both of its current capabilities and our ongoing research and development. PAGER monitors the USGS’s near real-time U.S. and global earthquake origins and automatically identifies events that are of societal importance, well in advance of ground-truth or news accounts. Current PAGER notifications and Web pages estimate the population exposed to each seismic intensity level. In addition to being a useful indicator of potential impact, PAGER’s intensity/exposure display provides a new standard in the dissemination of rapid earthquake information. We are currently developing and testing a more comprehensive alert system that will include casualty estimates. This is motivated by the idea that an estimated range of possible number of deaths will aid in decisions regarding humanitarian response. Underlying the PAGER exposure and loss models are global earthquake ShakeMap shaking estimates, constrained as quickly as possible by finite-fault modeling and observed ground motions and intensities, when available. Loss modeling is being developed comprehensively with a suite of candidate models that range from fully empirical to largely analytical approaches. Which of these models is most appropriate for use in a particular earthquake depends on how much is known about local building stocks and their vulnerabilities. A first-order country-specific global building inventory has been developed, as have corresponding vulnerability functions. For calibrating PAGER loss models, we have systematically generated an Atlas of 5,000 ShakeMaps for significant global earthquakes during the last 36 years. For many of these, auxiliary earthquake source and shaking intensity data are also available. Refinements to the loss models are ongoing

Application of an improved spectral decomposition method to examine earthquake source scaling in Southern California

NASA Astrophysics Data System (ADS)

Trugman, Daniel T.; Shearer, Peter M.

2017-04-01

Earthquake source spectra contain fundamental information about the dynamics of earthquake rupture. However, the inherent tradeoffs in separating source and path effects, when combined with limitations in recorded signal bandwidth, make it challenging to obtain reliable source spectral estimates for large earthquake data sets. We present here a stable and statistically robust spectral decomposition method that iteratively partitions the observed waveform spectra into source, receiver, and path terms. Unlike previous methods of its kind, our new approach provides formal uncertainty estimates and does not assume self-similar scaling in earthquake source properties. Its computational efficiency allows us to examine large data sets (tens of thousands of earthquakes) that would be impractical to analyze using standard empirical Green's function-based approaches. We apply the spectral decomposition technique to P wave spectra from five areas of active contemporary seismicity in Southern California: the Yuha Desert, the San Jacinto Fault, and the Big Bear, Landers, and Hector Mine regions of the Mojave Desert. We show that the source spectra are generally consistent with an increase in median Brune-type stress drop with seismic moment but that this observed deviation from self-similar scaling is both model dependent and varies in strength from region to region. We also present evidence for significant variations in median stress drop and stress drop variability on regional and local length scales. These results both contribute to our current understanding of earthquake source physics and have practical implications for the next generation of ground motion prediction assessments.

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.

The UK medical response to the Sichuan earthquake.

PubMed

Redmond, A D; Li, J

2011-06-01

At 14:48 on 12 May 2008 an earthquake of magnitude 8.0 struck the Wenchuan area of Sichuan province, China. A decision to offer/receive UK medical assistance was agreed at a Sino/British political level and a medical team was despatched to the earthquake area. This study describes the team's experience during the immediate aftermath of the earthquake and the following 18 months, during which there have been joint developments in emergency medicine, disaster planning/preparedness and the management of spinal cord injury. The long-term disability following sudden onset natural disaster and the wider impact on healthcare delivery may prove to be a greater burden to the country than the immediate medical needs, and, accordingly, emergency international aid may need to widen its focus. Although international teams usually arrive too late to support resuscitative measures, they can respond to specific requests for specialised assistance, for example plastic and reconstructive surgery to assist with the ongoing management of complex injury, relieve those who have worked continuously through the disaster, and when required maintain routine day-to-day services while local staff continue to manage the disaster. The timing of this does not necessarily need to be immediate. To maximise its impact, the team planned from the outset to build a relationship with Chinese colleagues that would lead to a sharing of knowledge and experience that would benefit major incident responses in both countries in the future. This has been established, and the linkage of emergency humanitarian assistance to longer term development should be considered by others the next time international emergency humanitarian assistance is contemplated.

Seismic displacement of gently-sloping coastal and marine sediment under multidirectional earthquake loading

USGS Publications Warehouse

Kayen, Robert E.

2017-01-01

Gentle sediment-laden slopes are typical of the onshore coastal zone and offshore continental shelf and slope. Coastal sediment are commonly young weakly consolidated materials that are well stratified, have low strength, and can mobilize shear displacements at low levels of stress. Seismically-driven plastic displacements of these sediment pose a hazard to coastal cities, buried onshore utilities, and offshore infrastructure like harbor protection and outfalls. One-dimensional rigid downslope-directed Newmark sliding block analyses have been used to predict earthquake deformations generally on steeper slopes that are modeled as frictional materials. This study probes the effect of multidirectional earthquake motions on inertial displacements of gently sloping ground of the coastal and offshore condition where soft-compliant soil is expected. Toward that objective, this investigation seeks to understand the effect on Newmark-type displacements of [1] multidirectional earthquake shaking and [2] soil compliance. In order to model multidirectional effects, the earthquake motions are rotated into the local slope strike- and dip-components. On gently sloping ground, including the strike component of motion always results in a larger and more accurate shear stress vector. Strike motions are found to contribute to downslope deformations on any declivity. Compliant response of the soil mass also influences the plastic displacements. The magnitude of seismic displacements can be estimated with a simplified model using only the estimated soil yield-acceleration (ky) and the peak ground velocity (Vmax) of the earthquake motions. Compliance effects can be effectively mapped using the concept of Plastic Displacement Response Spectra (PDRS).

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.

Emergency medical rescue efforts after a major earthquake: lessons from the 2008 Wenchuan earthquake.

PubMed

Zhang, Lulu; Liu, Xu; Li, Youping; Liu, Yuan; Liu, Zhipeng; Lin, Juncong; Shen, Ji; Tang, Xuefeng; Zhang, Yi; Liang, Wannian

2012-03-03

Major earthquakes often result in incalculable environmental damage, loss of life, and threats to health. Tremendous progress has been made in response to many medical challenges resulting from earthquakes. However, emergency medical rescue is complicated, and great emphasis should be placed on its organisation to achieve the best results. The 2008 Wenchuan earthquake was one of the most devastating disasters in the past 10 years and caused more than 370,000 casualties. The lessons learnt from the medical disaster relief effort and the subsequent knowledge gained about the regulation and capabilities of medical and military back-up teams should be widely disseminated. In this Review we summarise and analyse the emergency medical rescue efforts after the Wenchuan earthquake. Establishment of a national disaster medical response system, an active and effective commanding system, successful coordination between rescue forces and government agencies, effective treatment, a moderate, timely and correct public health response, and long-term psychological support are all crucial to reduce mortality and morbidity and promote overall effectiveness of rescue efforts after a major earthquake. Copyright © 2012 Elsevier Ltd. All rights reserved.

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

NASA Astrophysics Data System (ADS)

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

2013-12-01

100 m in horizontal and vertical, respectively. The grid spacing for the deep region is three times coarser. The total number of grid points is about three billion. The 3-D underground structure model used in the FD simulation is the Japan integrated velocity structure model (ERC, 2012). Our simulation is valid for period more than two seconds due to the lowest S-wave velocity and grid spacing. However, because the characterized source model may not sufficiently support short period components, we should be interpreted the reliable period of this simulation with caution. Therefore, we consider the period more than five seconds instead of two seconds for further analysis. We evaluate the long-period ground motions using the velocity response spectra for the period range between five and 20 second. The preliminary simulation shows a large variation of response spectra at a site. This large variation implies that the ground motion is very sensitive to different scenarios. And it requires studying the large variation to understand the seismic hazard. Our further study will obtain the hazard curves for the Nankai Trough earthquake (M 8~9) by applying the probabilistic seismic hazard analysis to the simulation results.

Response of Olive View Hospital to Northridge and Whittier earthquakes

USGS Publications Warehouse

Celebi, M.

1997-01-01

The purpose of this paper is to study the response of the conventionally designed new Olive View Medical Center (OVMC) building at 16 km from the epicenter of the January 17, 1994 Northridge, California earthquake (Ms = 6.8). OVMC is on an alluvial deposit. The building was subjected to design level peak accelerations during the earthquake and suffered only limited structural and nonstructural damage. The recorded motions at different levels of the OVMC building as well as its associated free-field sites are analyzed using spectral analyses and system identification techniques. The new OVMC building was conservatively designed in 1976 with very high lateral load resisting capability - particularly as a reaction to the detrimental fate of the original Olive View Hospital that was heavily damaged during the 1971 San Fernando earthquake. The original hospital building was later razed. The replacement structure, the new cross-shaped OVMC building, experienced peak acceleration of 2.31g at the roof while its peak ground floor acceleration was 0.82g. The free-field peak acceleration was 0.91g. The lateral load resisting system of the OVMC building consists of concrete shear walls in the lower two stories and steel shear walls at the perimeter of the upper four stories. Spectral analysis shows that this stiff structure was not affected by the long duration pulses of the motions recorded at this site.

Path spectra derived from inversion of source and site spectra for earthquakes in Southern California

NASA Astrophysics Data System (ADS)

Klimasewski, A.; Sahakian, V. J.; Baltay, A.; Boatwright, J.; Fletcher, J. B.; Baker, L. M.

2017-12-01

A large source of epistemic uncertainty in Ground Motion Prediction Equations (GMPEs) is derived from the path term, currently represented as a simple geometric spreading and intrinsic attenuation term. Including additional physical relationships between the path properties and predicted ground motions would produce more accurate and precise, region-specific GMPEs by reclassifying some of the random, aleatory uncertainty as epistemic. This study focuses on regions of Southern California, using data from the Anza network and Southern California Seismic network to create a catalog of events magnitude 2.5 and larger from 1998 to 2016. The catalog encompasses regions of varying geology and therefore varying path and site attenuation. Within this catalog of events, we investigate several collections of event region-to-station pairs, each of which share similar origin locations and stations so that all events have similar paths. Compared with a simple regional GMPE, these paths consistently have high or low residuals. By working with events that have the same path, we can isolate source and site effects, and focus on the remaining residual as path effects. We decompose the recordings into source and site spectra for each unique event and site in our greater Southern California regional database using the inversion method of Andrews (1986). This model represents each natural log record spectra as the sum of its natural log event and site spectra, while constraining each record to a reference site or Brune source spectrum. We estimate a regional, path-specific anelastic attenuation (Q) and site attenuation (t*) from the inversion site spectra and corner frequency from the inversion event spectra. We then compute the residuals between the observed record data, and the inversion model prediction (event*site spectra). This residual is representative of path effects, likely anelastic attenuation along the path that varies from the regional median attenuation. We examine the

Biomarker responses of mussels exposed to earthquake disturbances

NASA Astrophysics Data System (ADS)

Chandurvelan, Rathishri; Marsden, Islay D.; Glover, Chris N.; Gaw, Sally

2016-12-01

The green-lipped mussel, Perna canaliculus is recognised as a bioindicator of coastal contamination in New Zealand (NZ). Mussels (shell length 60-80 mm) were collected from three intertidal areas of Canterbury in the South Island of NZ prior to extreme earthquake disturbances on 22nd February 2011, and 9 months later in October 2011. Trace elements, including arsenic (As), cadmium (Cd), copper (Cu), lead (Pb), nickel (Ni), and zinc (Zn), were measured in the gills, digestive gland, foot and mantle. Metal levels in tissues were site specific, and mostly unaffected by earthquake disturbances. Physiological biomarkers were negatively affected by earthquake disturbances and mussels from the Port of Lyttelton had higher negative scope for growth post-earthquake. Metallothionein-like protein in the digestive gland correlated with metal content of tissues, as did catalase activity in the gill and lipid peroxidation values for the digestive gland. This research demonstrates that physiological and other biomarkers are effective at detecting the effects of multiple stressors following seismic disturbances.

Development of an Earthquake Impact Scale

NASA Astrophysics Data System (ADS)

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

2009-12-01

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

Modeling of the strong ground motion of 25th April 2015 Nepal earthquake using modified semi-empirical technique

NASA Astrophysics Data System (ADS)

Lal, Sohan; Joshi, A.; Sandeep; Tomer, Monu; Kumar, Parveen; Kuo, Chun-Hsiang; Lin, Che-Min; Wen, Kuo-Liang; Sharma, M. L.

2018-05-01

On 25th April, 2015 a hazardous earthquake of moment magnitude 7.9 occurred in Nepal. Accelerographs were used to record the Nepal earthquake which is installed in the Kumaon region in the Himalayan state of Uttrakhand. The distance of the recorded stations in the Kumaon region from the epicenter of the earthquake is about 420-515 km. Modified semi-empirical technique of modeling finite faults has been used in this paper to simulate strong earthquake at these stations. Source parameters of the Nepal aftershock have been also calculated using the Brune model in the present study which are used in the modeling of the Nepal main shock. The obtained value of the seismic moment and stress drop is 8.26 × 1025 dyn cm and 10.48 bar, respectively, for the aftershock from the Brune model .The simulated earthquake time series were compared with the observed records of the earthquake. The comparison of full waveform and its response spectra has been made to finalize the rupture parameters and its location. The rupture of the earthquake was propagated in the NE-SW direction from the hypocenter with the rupture velocity 3.0 km/s from a distance of 80 km from Kathmandu in NW direction at a depth of 12 km as per compared results.

North Anna Nuclear Power Plant Strong Motion Records of the Mineral, Virginia Earthquake of August 23, 2011

NASA Astrophysics Data System (ADS)

Graizer, V.

2012-12-01

The MW 5.8 Mineral, Virginia earthquake was recorded at a relatively short epicentral distance of about 18 km at the North Anna Nuclear Power Plant (NPP) by the SMA-3 magnetic tape digital accelerographs installed inside the plant's containment at the foundation and deck levels. The North Anna NPP is operated by the Virginia Electric and Power Company (VEPCO) and has two pressurized water reactors (PWR) units that began operation in 1978 and 1980, respectively. Following the earthquake, both units were safely shutdown. The strong-motion records were processed to get velocity, displacement, Fourier and 5% damped response spectra. The basemat record demonstrated relatively high amplitudes of acceleration of 0.26 g and velocity of 13.8 cm/sec with a relatively short duration of strong motion of 2-3 sec. Recorded 5% damped Response Spectra exceed Design Basis Earthquake for the existing Units 1 and 2, while comprehensive plant inspections performed by VEPCO and U.S. Nuclear Regulatory Commission have concluded that the damage to the plant was minimal not affecting any structures and equipment significant to plant operation. This can be explained in part by short duration of the earthquake ground motion at the plant. The North Anna NPP did not have free-field strong motion instrumentation at the time of the earthquake. Since the containment is founded on rock there is a tendency to consider basemat record as an approximation of the free-field recording. However, comparisons of deck and basemat records demonstrate that the basemat recording is also affected by structural resonance frequencies higher than 3 Hz. Structural resonances in the frequency range of 3-4 Hz can at least partially explain significant exceedance of observed motions relative to ground motion calculated using ground motion prediction equations.cceleration, velocity and displacement at the North Anna NPP basemat level. Amplitudes of acceleration, velocity and displacement at basemat and deck levels

Haitian and international responders' and decision-makers' perspectives regarding disability and the response to the 2010 Haiti earthquake.

PubMed

Hunt, Matthew R; Chung, Ryoa; Durocher, Evelyne; Henrys, Jean Hugues

2015-01-01

Following disasters, persons with disabilities (PWD) are especially vulnerable to harm, yet they have commonly been excluded from disaster planning, and their needs have been poorly addressed during disaster relief. Following the 2010 Haiti earthquake, thousands of individuals experienced acute injuries. Many more individuals with preexisting disabilities experienced heightened vulnerability related to considerations including safety, access to services, and meeting basic needs. The objective of this research was to better understand the perceptions of responders and decision-makers regarding disability and efforts to address the needs of PWD following the 2010 earthquake. We conducted a qualitative study using interpretive description methodology and semistructured interviews with 14 Haitian and 10 international participants who were involved in the earthquake response. Participants identified PWD as being among the most vulnerable individuals following the earthquake. Though some forms of disability received considerable attention in aid efforts, the needs of other PWD did not. Several factors were identified as challenges for efforts to address the needs of PWD including lack of coordination and information sharing, the involvement of multiple aid sectors, perceptions that this should be the responsibility of specialized organizations, and the need to prioritize limited resources. Participants also reported shifts in local social views related to disability following the earthquake. Addressing the needs of PWD following a disaster is a crucial population health challenge and raises questions related to equity and responsibility for non-governmental organizations, governments, and local communities.

Organizational changes at Earthquakes & Volcanoes

USGS Publications Warehouse

Gordon, David W.

1992-01-01

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

Ground motions recorded in Rome during the April 2009 L’Aquila seismic sequence: site response and comparison with ground‐motion predictions based on a global dataset

USGS Publications Warehouse

Caserta, Arrigo; Boore, David; Rovelli, Antonio; Govoni, Aladino; Marra, Fabrizio; Monica, Gieseppe Della; Boschi, Enzo

2013-01-01

The mainshock and moderate‐magnitude aftershocks of the 6 April 2009 M 6.3 L’Aquila seismic sequence, about 90 km northeast of Rome, provided the first earthquake ground‐motion recordings in the urban area of Rome. Before those recordings were obtained, the assessments of the seismic hazard in Rome were based on intensity observations and theoretical considerations. The L’Aquila recordings offer an unprecedented opportunity to calibrate the city response to central Apennine earthquakes—earthquakes that have been responsible for the largest damage to Rome in historical times. Using the data recorded in Rome in April 2009, we show that (1) published theoretical predictions of a 1 s resonance in the Tiber valley are confirmed by observations showing a significant amplitude increase in response spectra at that period, (2) the empirical soil‐transfer functions inferred from spectral ratios are satisfactorily fit through 1D models using the available geological, geophysical, and laboratory data, but local variability can be large for individual events, (3) response spectra for the motions recorded in Rome from the L’Aquila earthquakes are significantly amplified in the radial component at periods near 1 s, even at a firm site on volcanic rocks, and (4) short‐period response spectra are smaller than expected when compared to ground‐motion predictions from equations based on a global dataset, whereas the observed response spectra are higher than expected for periods near 1 s.

Responses of a 58-story RC dual core shear wall and outrigger frame building inferred from two earthquakes

USGS Publications Warehouse

Çelebi, Mehmet

2016-01-01

Responses of a dual core shear-wall and outrigger-framed 58-story building recorded during the Mw6.0 Napa earthquake of 24 August 2014 and the Mw3.8 Berkeley earthquake of 20 October 2011 are used to identify its dynamic characteristics and behavior. Fundamental frequencies are 0.28 Hz (NS), 0.25 Hz (EW), and 0.43 Hz (torsional). Rigid body motions due to rocking are not significant. Average drift ratios are small. Outrigger frames do not affect average drift ratios or mode shapes. Local site effects do not affect the response; however, response associated with deeper structure may be substantial. A beating effect is observed from data of both earthquakes but beating periods are not consistent. Low critical damping ratios may have contributed to the beating effect. Torsion is relatively larger above outriggers as indicated by the time-histories of motions at the roof, possibly due to the discontinuity of the stiffer shear walls above level 47.

International postseismic response after the Mw=7.8 April 16, 2016 Pedernales Earthquake in Ecuador

NASA Astrophysics Data System (ADS)

Font, Y.; Ruiz, M. C.; Alvarado, A. P.; Mercerat, D.; Beck, S. L.; Leon Rios, S.; Meltzer, A.; Charvis, P.; Regnier, M. M.; Jarrin, P.; Rietbrock, A.; Vasconez, F.; Dionicio, V.; Calvache, M. L.; Singaucho, J. C.; Pazmino, A.; Rolandone, F.; Mothes, P. A.; Nocquet, J. M.; Martin, X.; Viracucha, C.; Audin, L.; Saillard, M.; Laurendeau, A.; Perrault, M.; Garth, T.; Pernoud, M.; Barros, J. G.; Yates, B.; Malengros, D.; Oregioni, D.; Villegas Lanza, J. C.; Cisneros, D.; Gomez, J.; Montes, L.; Beauval, C. M.; Bertrand, E.; Delouis, B.; Ruiz Paspuel, A. G.; Freymueller, J. T.; Williams, K.; La Femina, P.; Fuenzalida, A.; Mariniere, J.; Cheze, J.; Gueguen, P.; Maron, C.; Michaud, F.; Yepes, H. A.; Palacios, P.; Vallee, M.; Deschamps, A.; Gabriela, P.; Ambrois, D.; Ramos, C.; Courboulex, F.

2016-12-01

The Pedernales earthquake is a large Mw7.8 subduction earthquake caused by the relative convergence between the Nazca and South American plates. It occured north of the city of Pedernales, at 21 km depth and struck the coastal and densely populated Manabi Province, causing many casualties, structural damages and widespread surficial deformation. The 2016 epicenter was located near the Mw 7.8 1942 epicenter. Both events are similar in size and probably ruptured the same segment, which also corresponds to the southern part of the 1906 Mw8.8 Ecuador-Colombia megathrust rupture zone. Immediately after the earthquake, an international team from Ecuador, France, Colombia, the United Kingdom, Peru and the United States coordinated a scientific response with the respective financial support of EPN, IRD and CNRS, SGC, NERC and NSF. Equipment was provided by IGEPN, IRD, CEREMA, SGC, LIVERPOOL, IRIS PASSCAL and UNAVCO. Within a 1.5 month, the team progressively deployed a temporary seismic network of about 70 accelerometer and seismic stations, and 17 continuous GPS stations, complementing the permanent seismic, accelerometer and geodetic network of the IG-EPN. The dense network covers the 300 x 150 km wide area affected by the earthquake, including a trench-parallel line of 10 ocean bottom seismometers deployed by the R/V Orion of INOCAR for 6 months, assuring a minimized azimuthal gap. Intense seismicity is observed up to 150 km N- and S-ward from the rupture zone aligning mainly along 3 seismic strips roughly perpendicular to the trench and also near the rupture area. Peak ground and spectral accelerations are compared with existing ground-motion prediction equations (GMPEs) developed for interface earthquakes. Different soil investigations were realized to highlight soil characteristics in cities. The geodetic observations captured the immediate afterslip and will help determining the time history of afterslip and viscoelastic relaxation in response to this earthquake. A

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.

Strong nonlinear dependence of the spectral amplification factors of deep Vrancea earthquakes magnitude

NASA Astrophysics Data System (ADS)

Marmureanu, Gheorghe; Ortanza Cioflan, Carmen; Marmureanu, Alexandru

2010-05-01

Nonlinear effects in ground motion during large earthquakes have long been a controversial issue between seismologists and geotechnical engineers. Aki wrote in 1993:"Nonlinear amplification at sediments sites appears to be more pervasive than seismologists used to think…Any attempt at seismic zonation must take into account the local site condition and this nonlinear amplification( Local site effects on weak and strong ground motion, Tectonophysics,218,93-111). In other words, the seismological detection of the nonlinear site effects requires a simultaneous understanding of the effects of earthquake source, propagation path and local geological site conditions. The difficulty for seismologists in demonstrating the nonlinear site effects has been due to the effect being overshadowed by the overall patterns of shock generation and path propagation. The researchers from National Institute for Earth Physics ,in order to make quantitative evidence of large nonlinear effects, introduced the spectral amplification factor (SAF) as ratio between maximum spectral absolute acceleration (Sa), relative velocity (Sv) , relative displacement (Sd) from response spectra for a fraction of critical damping at fundamental period and peak values of acceleration(a-max),velocity (v-max) and displacement (d-max),respectively, from processed strong motion record and pointed out that there is a strong nonlinear dependence on earthquake magnitude and site conditions.The spectral amplification factors(SAF) are finally computed for absolute accelerations at 5% fraction of critical damping (β=5%) in five seismic stations: Bucharest-INCERC(soft soils, quaternary layers with a total thickness of 800 m);Bucharest-Magurele (dense sand and loess on 350m); Cernavoda Nuclear Power Plant site (marl, loess, limestone on 270 m) Bacau(gravel and loess on 20m) and Iassy (loess, sand, clay, gravel on 60 m) for last strong and deep Vrancea earthquakes: March 4,1977 (MGR =7.2 and h=95 km);August 30

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.

Who is Responsible for Human Suffering due to Earthquakes?

NASA Astrophysics Data System (ADS)

Wyss, M.

2012-12-01

A court in L'Aquila, Italy, convicted seven to six years in prison and a combined fine of two million Euros for not following their "obligation to avoid death, injury and damage, or at least to minimize them," as the prosecution alleged. These men lose their jobs and pensions, and are banned from holding public office. Meanwhile, the town of L'Aquila is teeming with furious citizens, who are preparing additional civil suits against the defendants, whom they hold responsible for the deaths of their loved ones, killed by collapsing buildings during the magnitude 6.3 earthquake of April 6, 2009. Before this shock, an earthquake swarm had scared the inhabitants for several weeks. To calm the population, the vice-director of the Department of Civil Protection (DCP) called a meeting of the Italian Commission of Great Risks (CGR) in L'Aquila to assess the situation on March 31. One hour before this meeting, the vice-director stated in a TV interview that the seismic situation in L'Aquila was "certainly normal" and posed "no danger" and he added that "the scientific community continues to assure me that, to the contrary, it's a favorable situation because of the continuous discharge of energy." This statement is untrue in two ways. Firstly, small earthquakes do not release enough strain energy to reduce the potential for a large shock, and secondly no seismologist would make such a statement because we know it is not true. However, the population clung to the idea: "the more tremors, the less danger". People who lost relatives allege that they would have left their homes, had they not been falsely assured of their safety. The court treated all seven alike, although they had very different functions and obligations. Two were leaders in DCP, four were members of the CGR, and one was a seismology expert, who brought the latest seismic data. The minutes of the meeting show that none of the experts said anything wrong. They all stated that the probability of a main shock to

Moments, magnitudes, and radiated energies of non-volcanic tremor near Cholame, CA, from ground motion spectra at UPSAR

USGS Publications Warehouse

Fletcher, Joe B.; McGarr, A.

2011-01-01

By averaging the spectra of events within two episodes of tremor (on Jan. 21 and 24, 2005) across the 12 stations of UPSAR, we improved the S/N sufficiently to define source spectra. Analysis of eleven impulsive events revealed attenuation-corrected spectra of displacement similar to those of earthquakes, with a low-frequency plateau, a corner frequency, and a high frequency decay proportional to f−2. Seismic moments, M0, estimated from these spectra range from about 3 to 10 × 1011 N-m or moment magnitudes in the range 1.6 to 1.9. The corner frequencies range from 2.6 to 7.2 Hz and, if interpreted in the same way as for earthquakes, indicate low stress drops that vary from 0.001 to 0.04 MPa. Seismic energies, estimated from the ground motion spectra, vary from 0.2 × 105 to 4.4 × 105 J, or apparent stresses in the range 0.002 to 0.02 MPa. The low stress parameters are consistent with a weak fault zone in the lower crust at the depth of tremor. In contrast, the same analysis on a micro-earthquake, located near Cholame (depth = 10.3 km), revealed a stress drop of 0.5 MPa and an apparent stress of 0.02 MPa. Residual spectra from ω−2 model fits to the displacement spectra of the non-volcanic tremor events show peaks near 4 Hz that are not apparent in the spectra for the microearthquake nor for the spectrum of earth noise. These spectral peaks may indicate that tremor entails more than shear failure reminiscent of mechanisms, possibly entailing fluid flow, associated with volcanic tremor or deep volcanic earthquakes.

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. 

3D Ground-Motion Simulations for Magnitude 9 Earthquakes on the Cascadia Megathrust: Sedimentary Basin Amplification, Rupture Directivity, and Ground-Motion Variability

NASA Astrophysics Data System (ADS)

Frankel, A. D.; Wirth, E. A.; Marafi, N.; Vidale, J. E.; Stephenson, W. J.

2017-12-01

We have produced broadband (0-10 Hz) synthetic seismograms for Mw 9 earthquakes on the Cascadia subduction zone by combining synthetics from 3D finite-difference simulations at low frequencies (≤ 1 Hz) and stochastic synthetics at high frequencies (≥ 1 Hz). These synthetic ground motions are being used to evaluate building response, liquefaction, and landslides, as part of the M9 Project of the University of Washington, in collaboration with the U.S. Geological Survey. The kinematic rupture model is composed of high stress drop sub-events with Mw 8, similar to those observed in the Mw 9.0 Tohoku, Japan and Mw 8.8 Maule, Chile earthquakes, superimposed on large background slip with lower slip velocities. The 3D velocity model is based on active and passive-source seismic tomography studies, seismic refraction and reflection surveys, and geologic constraints. The Seattle basin portion of the model has been validated by simulating ground motions from local earthquakes. We have completed 50 3D simulations of Mw 9 earthquakes using a variety of hypocenters, slip distributions, sub-event locations, down-dip limits of rupture, and other parameters. For sites not in deep sedimentary basins, the response spectra of the synthetics for 0.1-6.0 s are similar, on average, to the values from the BC Hydro ground motion prediction equations (GMPE). For periods of 7-10 s, the synthetic response spectra exceed these GMPE, partially due to the shallow dip of the plate interface. We find large amplification factors of 2-5 for response spectra at periods of 1-10 s for locations in the Seattle and Tacoma basins, relative to sites outside the basins. This amplification depends on the direction of incoming waves and rupture directivity. The basin amplification is caused by surface waves generated at basin edges from incoming S-waves, as well as amplification and focusing of S-waves and surface waves by the 3D basin structure. The inter-event standard deviation of response spectral

[Expression of negative emotional responses to the 2011 Great East Japan Earthquake: Analysis of big data from social media].

PubMed

Miura, Asako; Komori, Masashi; Matsumura, Naohiro; Maeda, Kazutoshi

2015-06-01

In this article, we investigated the expression of emotional responses to the 2011 Great East Japan Earthquake by analyzing the frequency of negative emotional terms in tweets posted on Twitter, one of the most popular social media platforms. We focused on differences in time-series variations and diurnal changes between two kinds of disasters: natural disasters (earthquakes and tsunamis) and nuclear accidents. The number of tweets containing negative emotional responses increased sharply shortly after the first huge earthquake and decreased over time, whereas tweets about nuclear accidents showed no correlation with elapsed time. Expressions of anxiety about natural disasters had a circadian rhythm, with a peak at midnight, whereas expressions of anger about the nuclear accident were highly sensitive to critical events related to the accident. These findings were discussed in terms of similarities and differences compared to earlier studies on emotional responses in social media.

Impacts and responses : goods movement after the Northridge Earthquake

DOT National Transportation Integrated Search

1998-05-01

The 1994 Northridge earthquake disrupted goods movement on four major highway routes in : Southern California. This paper examines the impacts of the earthquake on Los Angeles County : trucking firms, and finds that the impact was initially widesprea...

Spatial and Temporal Stress Drop Variations of the 2011 Tohoku Earthquake Sequence

NASA Astrophysics Data System (ADS)

Miyake, H.

2013-12-01

The 2011 Tohoku earthquake sequence consists of foreshocks, mainshock, aftershocks, and repeating earthquakes. To quantify spatial and temporal stress drop variations is important for understanding M9-class megathrust earthquakes. Variability and spatial and temporal pattern of stress drop is a basic information for rupture dynamics as well as useful to source modeling. As pointed in the ground motion prediction equations by Campbell and Bozorgnia [2008, Earthquake Spectra], mainshock-aftershock pairs often provide significant decrease of stress drop. We here focus strong motion records before and after the Tohoku earthquake, and analyze source spectral ratios considering azimuth- and distance dependency [Miyake et al., 2001, GRL]. Due to the limitation of station locations on land, spatial and temporal stress drop variations are estimated by adjusting shifts from the omega-squared source spectral model. The adjustment is based on the stochastic Green's function simulations of source spectra considering azimuth- and distance dependency. We assumed the same Green's functions for event pairs for each station, both the propagation path and site amplification effects are cancelled out. Precise studies of spatial and temporal stress drop variations have been performed [e.g., Allmann and Shearer, 2007, JGR], this study targets the relations between stress drop vs. progression of slow slip prior to the Tohoku earthquake by Kato et al. [2012, Science] and plate structures. Acknowledgement: This study is partly supported by ERI Joint Research (2013-B-05). We used the JMA unified earthquake catalogue and K-NET, KiK-net, and F-net data provided by NIED.

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

NASA Astrophysics Data System (ADS)

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

2008-12-01

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

The role of the 2008 Mw 7.9 Wenchuan earthquake in topographic evolution: seismically induced landslides and the associated isostatic response

NASA Astrophysics Data System (ADS)

Ren, Z.; Zhang, Z.; Zhang, H.; Zheng, W.; Zhang, P. Z.

2017-12-01

The widely held understanding that reverse-faulting earthquakes play an important role in building mountains has been challenged by recent studies suggesting that co-seismic landslides of the 2008 Mw 7.9 Wenchuan earthquake led to a net co-seismic lowering of surface height. We use precise estimates of co-seismic landslide volumes to calculate the long-term isostatic response to landsliding during the 2008 Wenchuan earthquake. The total isostatic respond volume is 2.0 km3 which did not change much associated with thickness of Te, however, the distribution of the rebound changes associated with thickness of Te. The total co-seismic mass change could be 1.8 km3. The maximum isostatic response due to Wenchuan earthquake may have been as high as 0.9 meters in the highest Pengguan massif of the central Longmen Shan. We also find that the average net uplift is 0.16 meters within the total landslide region due to the Wenchuan earthquake. Our findings suggest that the local topographic evolution of the middle Longmen Shan region is closely related to repeated tectonic events such as the 2008 Wenchuan Earthquake.

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.

Multispectral, hyperspectral, and LiDAR remote sensing and geographic information fusion for improved earthquake response

NASA Astrophysics Data System (ADS)

Kruse, F. A.; Kim, A. M.; Runyon, S. C.; Carlisle, Sarah C.; Clasen, C. C.; Esterline, C. H.; Jalobeanu, A.; Metcalf, J. P.; Basgall, P. L.; Trask, D. M.; Olsen, R. C.

2014-06-01

The Naval Postgraduate School (NPS) Remote Sensing Center (RSC) and research partners have completed a remote sensing pilot project in support of California post-earthquake-event emergency response. The project goals were to dovetail emergency management requirements with remote sensing capabilities to develop prototype map products for improved earthquake response. NPS coordinated with emergency management services and first responders to compile information about essential elements of information (EEI) requirements. A wide variety of remote sensing datasets including multispectral imagery (MSI), hyperspectral imagery (HSI), and LiDAR were assembled by NPS for the purpose of building imagery baseline data; and to demonstrate the use of remote sensing to derive ground surface information for use in planning, conducting, and monitoring post-earthquake emergency response. Worldview-2 data were converted to reflectance, orthorectified, and mosaicked for most of Monterey County; CA. Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) data acquired at two spatial resolutions were atmospherically corrected and analyzed in conjunction with the MSI data. LiDAR data at point densities from 1.4 pts/m2 to over 40 points/ m2 were analyzed to determine digital surface models. The multimodal data were then used to develop change detection approaches and products and other supporting information. Analysis results from these data along with other geographic information were used to identify and generate multi-tiered products tied to the level of post-event communications infrastructure (internet access + cell, cell only, no internet/cell). Technology transfer of these capabilities to local and state emergency response organizations gives emergency responders new tools in support of post-disaster operational scenarios.

Comparisons of ground motions from five aftershocks of the 1999 Chi-Chi, Taiwan, earthquake with empirical predictions largely based on data from California

USGS Publications Warehouse

Wang, G.-Q.; Boore, D.M.; Igel, H.; Zhou, X.-Y.

2004-01-01

The observed ground motions from five large aftershocks of the 1999 Chi-Chi, Taiwan, earthquake are compared with predictions from four equations based primarily on data from California. The four equations for active tectonic regions are those developed by Abrahamson and Silva (1997), Boore et al. (1997), Campbell (1997, 2001), and Sadigh et al. (1997). Comparisons are made for horizontal-component peak ground accelerations and 5%-damped pseudoacceleration response spectra at periods between 0.02 sec and 5 sec. The observed motions are in reasonable agreement with the predictions, particularly for distances from 10 to 30 km. This is in marked contrast to the motions from the Chi-Chi mainshock, which are much lower than the predicted motions for periods less than about 1 sec. The results indicate that the low motions in the mainshock are not due to unusual, localized absorption of seismic energy, because waves from the mainshock and the aftershocks generally traverse the same section of the crust and are recorded at the same stations. The aftershock motions at distances of 30-60 km are somewhat lower than the predictions (but not nearly by as small a factor as those for the mainshock), suggesting that the ground motion attenuates more rapidly in this region of Taiwan than it does in the areas we compare with it. We provide equations for the regional attenuation of response spectra, which show increasing decay of motion with distance for decreasing oscillator periods. This observational study also demonstrates that ground motions have large earthquake-location-dependent variability for a specific site. This variability reduces the accuracy with which an earthquake-specific prediction of site response can be predicted. Online Material: PGAs and PSAs from the 1999 Chi-Chi earthquake and five aftershocks.

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

PubMed

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

2012-01-01

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

Increasing critical sensitivity of the Load/Unload Response Ratio before large earthquakes with identified stress accumulation pattern

NASA Astrophysics Data System (ADS)

Yu, Huai-zhong; Shen, Zheng-kang; Wan, Yong-ge; Zhu, Qing-yong; Yin, Xiang-chu

2006-12-01

The Load/Unload Response Ratio (LURR) method is proposed for short-to-intermediate-term earthquake prediction [Yin, X.C., Chen, X.Z., Song, Z.P., Yin, C., 1995. A New Approach to Earthquake Prediction — The Load/Unload Response Ratio (LURR) Theory, Pure Appl. Geophys., 145, 701-715]. This method is based on measuring the ratio between Benioff strains released during the time periods of loading and unloading, corresponding to the Coulomb Failure Stress change induced by Earth tides on optimally oriented faults. According to the method, the LURR time series usually climb to an anomalously high peak prior to occurrence of a large earthquake. Previous studies have indicated that the size of critical seismogenic region selected for LURR measurements has great influence on the evaluation of LURR. In this study, we replace the circular region usually adopted in LURR practice with an area within which the tectonic stress change would mostly affect the Coulomb stress on a potential seismogenic fault of a future event. The Coulomb stress change before a hypothetical earthquake is calculated based on a simple back-slip dislocation model of the event. This new algorithm, by combining the LURR method with our choice of identified area with increased Coulomb stress, is devised to improve the sensitivity of LURR to measure criticality of stress accumulation before a large earthquake. Retrospective tests of this algorithm on four large earthquakes occurred in California over the last two decades show remarkable enhancement of the LURR precursory anomalies. For some strong events of lesser magnitudes occurred in the same neighborhoods and during the same time periods, significant anomalies are found if circular areas are used, and are not found if increased Coulomb stress areas are used for LURR data selection. The unique feature of this algorithm may provide stronger constraints on forecasts of the size and location of future large events.

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.

Along-Arc and Back-Arc Attenuation, Site Response, and Source Spectrum for the Intermediate-Depth 8 January 2006 M 6.7 Kythera, Greece, Earthquake

USGS Publications Warehouse

Boore, David M.; Skarlatoudis, A.A.; Margaris, B.N.; Costas, B.P.; Ventouzi, C.

2009-01-01

An M 6.7 intermediate-depth (66 km), in-slab earthquake occurring near the island of Kythera in Greece on 8 January 2006 was well recorded on networks of stations equipped with acceleration sensors and with broadband velocity sensors. All data were recorded digitally using recording instruments with resolutions ranging from almost 11 to 24 bits. We use data from these networks to study the distance dependence of the horizontal-component Fourier acceleration spectra (FAS) and horizontal-component pseudoabsolute response spectral acceleration (PSA). For purposes of simulating motions in the future, we parameterize the distance decay using several forms of the geometrical-spreading function, for each of which we derive Q as a function of frequency. By extrapolating the distance decay back to 1 km, we obtain a reference spectrum that can be used in future simulations. This spectrum requires a more complicated spectral shape than the classic single-corner-frequency model; in particular, there appears to be an enhancement of motion around 0.2-0.3 Hz that may be due to the radiation of a 3-5 sec pulse from the source. We infer a ??0 value of about 0.055 sec for rock stations and a stress parameter in the range of 400-600 bars. We also find distinctive differences in the site response of stations on soft soil and soil; both the FAS and the 5% damped PSA amplifications have similar peak amplitudes (about 2 and 4 for soil and soft-soil sites, respectively, relative to the rock sites) at similar frequencies (between about 0.4 and 2.0 Hz, with the soft-soil amplifications peaking at somewhat lower frequencies than the soil amplifications). One of the most distinctive features of the data is the clear difference in the motions for along-arc and back-arc stations, with the former being significantly higher than the latter over a broad range of frequencies at distances beyond about 250 km. The motions from the Kythera earthquake are roughly comparable to those from intermediate

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.

Earthquake Response of Concrete Gravity Dams Including Hydrodynamic and Foundation Interaction Effects,

DTIC Science & Technology

1980-01-01

standard procedure for Analysis of all types of civil engineering struc- tures. Early in its development, it became apparent that this method had...unique potentialities in the evaluation of stress in dams, and many of its earliest civil engineering applications concerned special problems associated...with such structures [3,4]. The earliest dynamic finite element analyses of civil engineering structures involved the earthquake response analysis of

Real-time seismic monitoring of the integrated cape girardeau bridge array and recorded earthquake response

USGS Publications Warehouse

Celebi, M.

2006-01-01

This paper introduces the state of the art, real-time and broad-band seismic monitoring network implemented for the 1206 m [3956 ft] long, cable-stayed Bill Emerson Memorial Bridge in Cape Girardeau (MO), a new Mississippi River crossing, approximately 80 km from the epicentral region of the 1811-1812 New Madrid earthquakes. The bridge was designed for a strong earthquake (magnitude 7.5 or greater) during the design life of the bridge. The monitoring network comprises a total of 84 channels of accelerometers deployed on the superstructure, pier foundations and at surface and downhole free-field arrays of the bridge. The paper also presents the high quality response data obtained from the network. Such data is aimed to be used by the owner, researchers and engineers to assess the performance of the bridge, to check design parameters, including the comparison of dynamic characteristics with actual response, and to better design future similar bridges. Preliminary analyses of ambient and low amplitude small earthquake data reveal specific response characteristics of the bridge and the free-field. There is evidence of coherent tower, cable, deck interaction that sometimes results in amplified ambient motions. Motions at the lowest tri-axial downhole accelerometers on both MO and IL sides are practically free from any feedback from the bridge. Motions at the mid-level and surface downhole accelerometers are influenced significantly by feedback due to amplified ambient motions of the bridge. Copyright ASCE 2006.

The response of creeping parts of the San Andreas fault to earthquakes on nearby faults: Two examples

USGS Publications Warehouse

Simpson, R.W.; Schulz, S.S.; Dietz, L.D.; Burford, R.O.

1988-01-01

Rates of shallow slip on creeping sections of the San Andreas fault have been perturbed on a number of occasions by earthquakes occurring on nearby faults. One example of such perturbations occurred during the 26 January 1986 magnitude 5.3 Tres Pinos earthquake located about 10 km southeast of Hollister, California. Seven creepmeters on the San Andreas fault showed creep steps either during or soon after the shock. Both left-lateral (LL) and right-lateral (RL) steps were observed. A rectangular dislocation in an elastic half-space was used to model the coseismic fault offset at the hypocenter. For a model based on the preliminary focal mechanism, the predicted changes in static shear stress on the plane of the San Andreas fault agreed in sense (LL or RL) with the observed slip directions at all seven meters; for a model based on a refined focal mechanism, six of the seven meters showed the correct sense of motion. Two possible explanations for such coseismic and postseismic steps are (1) that slip was triggered by the earthquake shaking or (2) that slip occurred in response to the changes in static stress fields accompanying the earthquake. In the Tres Pinos example, the observed steps may have been of both the triggered and responsive kinds. A second example is provided by the 2 May 1983 magnitude 6.7 Coalinga earthquake, which profoundly altered slip rates at five creepmeters on the San Andreas fault for a period of months to years. The XMM1 meter 9 km northwest of Parkfield, California recorded LL creep for more than a year after the event. To simulate the temporal behavior of the XMM1 meter and to view the stress perturbation provided by the Coalinga earthquake in the context of steady-state deformation on the San Andreas fault, a simple time-evolving dislocation model was constructed. The model was driven by a single long vertical dislocation below 15 km in depth, that was forced to slip at 35 mm/yr in a RL sense. A dislocation element placed in the

Real-time earthquake monitoring: Early warning and rapid response

NASA Technical Reports Server (NTRS)

1991-01-01

A panel was established to investigate the subject of real-time earthquake monitoring (RTEM) and suggest recommendations on the feasibility of using a real-time earthquake warning system to mitigate earthquake damage in regions of the United States. The findings of the investigation and the related recommendations are described in this report. A brief review of existing real-time seismic systems is presented with particular emphasis given to the current California seismic networks. Specific applications of a real-time monitoring system are discussed along with issues related to system deployment and technical feasibility. In addition, several non-technical considerations are addressed including cost-benefit analysis, public perceptions, safety, and liability.

Ground motion estimation in Delhi from postulated regional and local earthquakes

NASA Astrophysics Data System (ADS)

Mittal, Himanshu; Kumar, Ashok; Kamal

2013-04-01

Ground motions are estimated at 55 sites in Delhi, the capital of India from four postulated earthquakes (three regional M w = 7.5, 8.0, and 8.5 and one local). The procedure consists of (1) synthesis of ground motion at a hard reference site (NDI) and (2) estimation of ground motion at other sites in the city via known transfer functions and application of the random vibration theory. This work provides a more extensive coverage than earlier studies (e.g., Singh et al., Bull Seism Soc Am 92:555-569, 2002; Bansal et al., J Seismol 13:89-105, 2009). The Indian code response spectra corresponding to Delhi (zone IV) are found to be conservative at hard soil sites for all postulated earthquakes but found to be deficient for M w = 8.0 and 8.5 earthquakes at soft soil sites. Spectral acceleration maps at four different natural periods are strongly influenced by the shallow geological and soil conditions. Three pockets of high acceleration values are seen. These pockets seem to coincide with the contacts of (a) Aravalli quartzite and recent Yamuna alluvium (towards the East), (b) Aravalli quartzite and older quaternary alluvium (towards the South), and (c) older quaternary alluvium and recent Yamuna alluvium (towards the North).

Atmosphere-Ionosphere Response to the M9 Tohoku Earthquake Revealed by Joined Satellite and Ground Observations. Preliminary Results

NASA Technical Reports Server (NTRS)

Ouzounov, Dimitar; Pulinets, Sergey; Romanov, Alexey; Tsybulya, Konstantin; Davidenko, Dimitri; Kafatos, Menas; Taylor, Patrick

2011-01-01

The recent M9 Tohoku Japan earthquake of March 11, 2011 was the largest recorded earthquake ever to hit this nation. We retrospectively analyzed the temporal and spatial variations of four different physical parameters - outgoing long wave radiation (OLR), GPS/TEC, Low-Earth orbit tomography and critical frequency foF2. These changes characterize the state of the atmosphere and ionosphere several days before the onset of this earthquake. Our first results show that on March 8th a rapid increase of emitted infrared radiation was observed from the satellite data and an anomaly developed near the epicenter. The GPS/TEC data indicate an increase and variation in electron density reaching a maximum value on March 8. Starting on this day in the lower ionospheric there was also confirmed an abnormal TEC variation over the epicenter. From March 3-11 a large increase in electron concentration was recorded at all four Japanese ground based ionosondes, which return to normal after the main earthquake. We found a positive correlation between the atmospheric and ionospheric anomalies and the Tohoku earthquake. This study may lead to a better understanding of the response of the atmosphere/ionosphere to the Great Tohoku earthquake.

Response of high-rise and base-isolated buildings to a hypothetical M w 7.0 blind thrust earthquake

USGS Publications Warehouse

Heaton, T.H.; Hall, J.F.; Wald, D.J.; Halling, M.W.

1995-01-01

High-rise flexible-frame buildings are commonly considered to be resistant to shaking from the largest earthquakes. In addition, base isolation has become increasingly popular for critical buildings that should still function after an earthquake. How will these two types of buildings perform if a large earthquake occurs beneath a metropolitan area? To answer this question, we simulated the near-source ground motions of a Mw 7.0 thrust earthquake and then mathematically modeled the response of a 20-story steel-frame building and a 3-story base-isolated building. The synthesized ground motions were characterized by large displacement pulses (up to 2 meters) and large ground velocities. These ground motions caused large deformation and possible collapse of the frame building, and they required exceptional measures in the design of the base-isolated building if it was to remain functional.

Earthquakes-Rattling the Earth's Plumbing System

USGS Publications Warehouse

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

2003-01-01

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

Determination of Focal Depths of Earthquakes in the Mid-Oceanic Ridges from Amplitude Spectra of Surface Waves

DTIC Science & Technology

1969-06-01

Foreshock , mainshock and aftershock of the Parkfield, California earthquake of June 28, 1966. b. The Denver earthquake of August 9, 1967. Let us look...into the results of these tests in more details. (1) Test on the main shock, foreshock and aftershock of the Parkfield earthquake of June 28, 1966...According to McEvilly et. al. (1967), the origin times and locations of.these events were the following: Foreshock June 28, 1966, 04:08:56.2 GMT; 350 57.6

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

Seismoelectric ground response to local and regional earthquakes

NASA Astrophysics Data System (ADS)

Dzieran, Laura; Rabbel, Wolfgang; Thorwart, Martin; Ritter, Oliver

2017-04-01

During earthquakes magnetotelluric stations occasionally record electric and magnetic signals similar to seismograms. The major part of these magnetic signals is induced by the seismic movement of the magnetometers (induction coils) in the static magnetic field. In contrast, the electric field signals are caused by the seismoelectric effect. Based on more than 600 earthquakes from Chile, Costa Rica and Europe we established a logarithmic magnitude-distance-relationship describing the magnitude threshold to be exceeded for observing seismoelectric (SE) signals with standard magnetotelluric (MT) recording units at given hypocentral distance r and for noise levels less than 3 μV/m. The log(r) term results from the geometric spreading of the radiated seismic waves. A comparison of SE signals at different hypocentral distances shows that observability is not only influenced by the amplitude of the incoming seismic wave. It also depends on the geological structure underneath the station which causes a unique frequency dependent SE response. To quantify these site effects we computed spectral seismoelectric transfer functions representing the ratios of the spectral amplitudes of SE records and acceleration seismograms (SESRs). Some stations show constant SESRs in the major frequency range, while others show a decrease with increasing frequencies. Based on the current Biot-type seismoelectric theory constant SESRs can be explained by coseismic SE waves alone. The observed SESR amplitudes at some sites are indeed consistent with theoretical expectations for electrically highly resistive soils or rocks, in agreement with the local geology of the investigated areas. The frequency dependence of SESRs observed at other locations can be explained if the incident SE waves consist not only of coseismic arrivals but also of a significant contribution from SE interface response waves which are generated at electrical or mechanical boundaries. Therefore, frequency-dependent SESRs

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

USGS Publications Warehouse

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

2013-01-01

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

A Cooperative Test of the Load/Unload Response Ratio Proposed Method of Earthquake Prediction

NASA Astrophysics Data System (ADS)

Trotta, J. E.; Tullis, T. E.

2004-12-01

The Load/Unload Response Ratio (LURR) method is a proposed technique to predict earthquakes that was first put forward by Yin in 1984 (Yin, 1987). LURR is based on the idea that when a region is near failure, there is an increase in the rate of seismic activity during loading of the tidal cycle relative to the rate of seismic activity during unloading of the tidal cycle. Typically the numerator of the LURR ratio is the number, or the sum of some measure of the size (e.g. Benioff strain), of small earthquakes that occur during loading of the tidal cycle, whereas the denominator is the same as the numerator except it is calculated during unloading. LURR method suggests this ratio should increase in the months to year preceding a large earthquake. Regions near failure have tectonic stresses nearly high enough for a large earthquake to occur, thus it seems more likely that smaller earthquakes in the region would be triggered when the tidal stresses add to the tectonic ones. However, until recently even the most careful studies suggested that the effect of tidal stresses on earthquake occurrence is very small and difficult to detect. New studies have shown that there is a tidal triggering effect on shallow thrust faults in areas with strong tides from ocean loading (Tanaka et al., 2002; Cochran et al., 2004). We have been conducting an independent test of the LURR method, since there would be important scientific and social implications if the LURR method were proven to be a robust method of earthquake prediction. Smith and Sammis (2003) also undertook a similar study. Following both the parameters of Yin et al. (2000) and the somewhat different ones of Smith and Sammis (2003), we have repeated calculations of LURR for the Northridge and Loma Prieta earthquakes in California. Though we have followed both sets of parameters closely, we have been unable to reproduce either set of results. A general agreement was made at the recent ACES Workshop in China between research

Response mechanism of post-earthquake slopes under heavy rainfall

NASA Astrophysics Data System (ADS)

Qiu, Hong-zhi; Kong, Ji-ming; Wang, Ren-chao; Cui, Yun; Huang, Sen-wang

2017-07-01

This paper uses the catastrophic landslide that occurred in Zhongxing Town, Dujiangyan City, as an example to study the formation mechanism of landslides induced by heavy rainfall in the post-Wenchuan earthquake area. The deformation characteristics of a slope under seismic loading were investigated via a shaking table test. The results show that a large number of cracks formed in the slope due to the tensile and shear forces of the vibrations, and most of the cracks had angles of approximately 45° with respect to the horizontal. A series of flume tests were performed to show how the duration and intensity of rainfall influence the responses of the shaken and non-shaken slopes. Wetting fronts were recorded under different rainfall intensities, and the depth of rainfall infiltration was greater in the shaken slope than in the non-shaken slope because the former experienced a greater extreme rainfall intensity under the same early rainfall and rainfall duration conditions. At the beginning of the rainfall infiltration experiment, the pore water pressure in the slope was negative, and settling occurred at the top of the slope. With increasing rainfall, the pore water pressure changed from negative to positive, and cracks were observed on the back surface of the slope and the shear outlet of the landslide on the front of the slope. The shaken slope was more susceptible to crack formation than the non-shaken slope under the same rainfall conditions. A comparison of the responses of the shaken and non-shaken slopes under heavy rainfall revealed that cracks formed by earthquakes provided channels for infiltration. Soil particles in the cracks of slopes were washed away, and the pore water pressure increased rapidly, especially the transient pore water pressure in the slope caused by short-term concentrated rainfall which decreased rock strength and slope stability.

Hydrogeochemical response of groundwater springs during central Italy earthquakes (24 August 2016 and 26-30 October 2016)

NASA Astrophysics Data System (ADS)

Archer, Claire; Binda, Gilberto; Terrana, Silvia; Gambillara, Roberto; Michetti, Alessandro; Noble, Paula; Petitta, Marco; Rosen, Michael; Pozzi, Andrea; Bellezza, Paolo; Brunamonte, Fabio

2017-04-01

Co-seismic hydrological and chemical response at groundwater springs following strong earthquakes is a significant concern in the Apennines, a region in central Italy characterized by regional karstic groundwater systems interacting with active normal faults capable of producing Mw 6.5 to 7.0 seismic events. These aquifers also provide water supply to major metropolitan areas in the region. On August 24, 2016, a Mw 6.0 earthquake hit Central Italy in the area where Latium joins Umbria, Marche and Abruzzi; this was immediately followed one hour later by a Mw 5.4 shock. The epicenter of the event was located at the segment boundary between the Mt. Vettore and Mt. Laga faults. On October 26, 2016 and on October 30, 2016, three other big shocks (Mw 5.5, Mw 6.0 and Mw 6.5) ruptured again the Vettore Fault and its NW extension. Immediately after Aug. 24, we sampled springs discharging different aquifers in the Rieti area, including the Peschiera spring, which feeds the aqueduct of Rome. Thermal springs connected with deep groundwater flowpaths were also sampled. These springs, sampled previously in 2014 and 2015, provide some pre-earthquake data. Moreover, we sampled 4 springs along the Mt. Vettore fault system: 3 small springs at Forca di Presta, close to the trace of the earthquake surface ruptures, and two in Castel Sant'Angelo sul Nera. The latter are feeding the Nera aqueduct and the Nerea S.p.A. mineral water plant, which also kindly allowed us to collect bottled water samples from the pre-seismic period. The aim of this study is to evaluate the strong earthquake sequence effects on the hydrochemistry and flow paths of groundwater from different aquifer settings based on analysis before and after seismic events. The comparison between the responses of springs ca. 40 km from the epicenter (Rieti basin) and the springs located near the epicenter (Castelsantangelo sul Nera and Forca di Presta) is especially significant for understanding the resilience of groundwater

Response spectra analysis of the modal summation technique verified by observed seismometer and accelerometer waveform data of the M6.5 Pidie Jaya Earthquake

NASA Astrophysics Data System (ADS)

Irwandi; Rusydy, Ibnu; Muksin, Umar; Rudyanto, Ariska; Daryono

2018-05-01

Wave vibration confined in the boundary will produce stationary wave solution in discrete states called modes. There are many physics applications related to modal solutions such as air column resonance, string vibration, and emission spectrum of the atomic Hydrogen. Naturally, energy is distributed in several modes so that the complete calculation is obtained from the sum of the whole modes called modal summation. The modal summation technique was applied to simulate the surface wave propagation above crustal structure of the earth. The method is computational because it uses 1D structural model which is not necessary to calculate the overall wave propagation. The simulation results of the magnitude 6.5 Pidie Jaya earthquake show the response spectral of the Summation Technique has a good correlation to the observed seismometer and accelerometer waveform data, especially at the KCSI (Kotacane) station. On the other hand, at the LASI (Langsa) station shows the modal simulation result of response is relatively lower than observation. The lower value of the reaction spectral estimation is obtained because the station is located in the thick sedimentary basin causing the amplification effect. This is the limitation of modal summation technique, and therefore it should be combined with different finite simulation on the 2D local structural model of the basin.

Preliminary results on earthquake triggered landslides for the Haiti earthquake (January 2010)

NASA Astrophysics Data System (ADS)

van Westen, Cees; Gorum, Tolga

2010-05-01

This study presents the first results on an analysis of the landslides triggered by the Ms 7.0 Haiti earthquake that occurred on January 12, 2010 in the boundary region of the Pacific Plate and the North American plate. The fault is a left lateral strike slip fault with a clear surface expression. According to the USGS earthquake information the Enriquillo-Plantain Garden fault system has not produced any major earthquake in the last 100 years, and historical earthquakes are known from 1860, 1770, 1761, 1751, 1684, 1673, and 1618, though none of these has been confirmed in the field as associated with this fault. We used high resolution satellite imagery available for the pre and post earthquake situations, which were made freely available for the response and rescue operations. We made an interpretation of all co-seismic landslides in the epicentral area. We conclude that the earthquake mainly triggered landslide in the northern slope of the fault-related valley and in a number of isolated area. The earthquake apparently didn't trigger many visible landslides within the slum areas on the slopes in the southern part of Port-au-Prince and Carrefour. We also used ASTER DEM information to relate the landslide occurrences with DEM derivatives.

Earthquake Intensity and Strong Motion Analysis Within SEISCOMP3

NASA Astrophysics Data System (ADS)

Becker, J.; Weber, B.; Ghasemi, H.; Cummins, P. R.; Murjaya, J.; Rudyanto, A.; Rößler, D.

2017-12-01

Measuring and predicting ground motion parameters including seismic intensities for earthquakes is crucial and subject to recent research in engineering seismology.gempa has developed the new SIGMA module for Seismic Intensity and Ground Motion Analysis. The module is based on the SeisComP3 framework extending it in the field of seismic hazard assessment and engineering seismology. SIGMA may work with or independently of SeisComP3 by supporting FDSN Web services for importing earthquake or station information and waveforms. It provides a user-friendly and modern graphical interface for semi-automatic and interactive strong motion data processing. SIGMA provides intensity and (P)SA maps based on GMPE's or recorded data. It calculates the most common strong motion parameters, e.g. PGA/PGV/PGD, Arias intensity and duration, Tp, Tm, CAV, SED and Fourier-, power- and response spectra. GMPE's are configurable. Supporting C++ and Python plug-ins, standard and customized GMPE's including the OpenQuake Hazard Library can be easily integrated and compared. Originally tailored to specifications by Geoscience Australia and BMKG (Indonesia) SIGMA has become a popular tool among SeisComP3 users concerned with seismic hazard and strong motion seismology.

Mantle Attenuation Estimated from Regional and Teleseismic P-waves of Deep Earthquakes and Surface Explosions

NASA Astrophysics Data System (ADS)

Ichinose, G.; Woods, M.; Dwyer, J.

2014-03-01

We estimated the network-averaged mantle attenuation t*(total) of 0.5 s beneath the North Korea test site (NKTS) by use of P-wave spectra and normalized spectral stacks from the 25 May 2009 declared nuclear test (mb 4.5; IDC). This value was checked using P-waves from seven deep (580-600 km) earthquakes (4.8 < M w < 5.5) in the Jilin-Heilongjiang, China region that borders with Russia and North Korea. These earthquakes are 200-300 km from the NKTS, within 200 km of the Global Seismic Network seismic station in Mudanjiang, China (MDJ) and the International Monitoring System primary arrays at Ussuriysk, Russia (USRK) and Wonju, Republic of Korea (KSRS). With the deep earthquakes, we split the t*(total) ray path into two segments: a t*(u), that represents the attenuation of the up-going ray from the deep hypocenters to the local-regional receivers, and t*(d), that represents the attenuation along the down-going ray to teleseismic receivers. The sum of t*(u) and t*(d) should be equal to t*(total), because they both share coincident ray paths. We estimated the upper-mantle attenuation t*(u) of 0.1 s at stations MDJ, USRK, and KSRS from individual and stacks of normalized P-wave spectra. We then estimated the average lower-mantle attenuation t*(d) of 0.4 s using stacked teleseismic P-wave spectra. We finally estimated a network average t*(total) of 0.5 s from the stacked teleseismic P-wave spectra from the 2009 nuclear test, which confirms the equality with the sum of t*(u) and t*(d). We included constraints on seismic moment, depth, and radiation pattern by using results from a moment tensor analysis and corner frequencies from modeling of P-wave spectra recorded at local distances. We also avoided finite-faulting effects by excluding earthquakes with complex source time functions. We assumed ω2 source models for earthquakes and explosions. The mantle attenuation beneath the NKTS is clearly different when compared with the network-averaged t* of 0.75 s for the western

Earthquake ground motion simulation at Zoser pyramid using the stochastic method: A step toward the preservation of an ancient Egyptian heritage

NASA Astrophysics Data System (ADS)

Khalil, Amin E.; Abdel Hafiez, H. E.; Girgis, Milad; Taha, M. A.

2017-06-01

Strong ground shaking during earthquakes can greatly affect the ancient monuments and subsequently demolish the human heritage. On October 12th 1992, a moderate earthquake (Ms = 5.8) shocked the greater Cairo area causing widespread damages. Unfortunately, the focus of that earthquake is located about 14 km to the south of Zoser pyramid. After the earthquake, the Egyptian Supreme council of antiquities issued an alarm that Zoser pyramid is partially collapsed and international and national efforts are exerted to restore this important human heritage that was built about 4000 years ago. Engineering and geophysical work is thus needed for the restoration process. The definition of the strong motion parameters is one of the required studies since seismically active zone is recorded in its near vicinity. The present study adopted the stochastic method to determine the peak ground motion (acceleration, velocity and displacement) for the three largest earthquakes recorded in the Egypt's seismological history. These earthquakes are Shedwan earthquake with magnitude Ms = 6.9, Aqaba earthquake with magnitude Mw = 7.2 and Cairo (Dahshour earthquake) with magnitude Ms = 5.8. The former two major earthquakes took place few hundred kilometers away. It is logic to have the predominant effects from the epicentral location of the Cairo earthquake; however, the authors wanted to test also the long period effects of the large distance earthquakes expected from the other two earthquakes under consideration. In addition, the dynamic site response was studied using the Horizontal to vertical spectral ratio (HVSR) technique. HVSR can provide information about the fundamental frequency successfully; however, the amplification estimation is not accepted. The result represented as either peak ground motion parameters or response spectra indicates that the effects from Cairo earthquake epicenter are the largest for all periods considered in the present study. The level of strong motion as

USGS Earthquake Program GPS Use Case : Earthquake Early Warning

DOT National Transportation Integrated Search

2015-03-12

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

Study of responses of 64-story Rincon Building to Napa, Fremont, Piedmont, San Ramon earthquakes and ambient motions

USGS Publications Warehouse

Çelebi, Mehmet; Hooper, John; Klemencic, Ron

2017-01-01

We analyze the recorded responses of a 64-story, instrumented, concrete core shear wall building in San Francisco, California, equipped with tuned sloshing liquid dampers (TSDs) and buckling restraining braces (BRBs). Previously, only ambient data from the 72-channel array in the building were studied (Çelebi et al. 2013). Recently, the 24 August 2014 Mw 6.0 Napa and three other earthquakes were recorded. The peak accelerations of ambient and the larger Napa earthquake responses at the basement are 0.12 cm/s/s and 5.2 cm/s/s respectively—a factor of ~42. At the 61st level, they are 0.30 cm/s/s (ambient) and 16.8 cm/s/s (Napa), respectively—a factor of ~56. Fundamental frequencies (NS ~ 0.3, EW ~ 0.27 Hz) from earthquake responses vary within an insignificant frequency band of ~0.02–0.03 Hz when compared to those from ambient data. In the absence of soil-structure interaction (SSI), these small and insignificant differences may be attributed to (1) identification errors, (2) any nonlinear behavior, and (3) shaking levels that are not large enough to activate the BRBs and TSDs to make significant shifts in frequencies and increase damping.

Hydrothermal response to a volcano-tectonic earthquake swarm, Lassen, California

USGS Publications Warehouse

Ingebritsen, Steven E.; Shelly, David R.; Hsieh, Paul A.; Clor, Laura; P.H. Seward,; Evans, William C.

2015-01-01

The increasing capability of seismic, geodetic, and hydrothermal observation networks allows recognition of volcanic unrest that could previously have gone undetected, creating an imperative to diagnose and interpret unrest episodes. A November 2014 earthquake swarm near Lassen Volcanic National Park, California, which included the largest earthquake in the area in more than 60 years, was accompanied by a rarely observed outburst of hydrothermal fluids. Although the earthquake swarm likely reflects upward migration of endogenous H2O-CO2 fluids in the source region, there is no evidence that such fluids emerged at the surface. Instead, shaking from the modest sized (moment magnitude 3.85) but proximal earthquake caused near-vent permeability increases that triggered increased outflow of hydrothermal fluids already present and equilibrated in a local hydrothermal aquifer. Long-term, multiparametric monitoring at Lassen and other well-instrumented volcanoes enhances interpretation of unrest and can provide a basis for detailed physical modeling.

Aftershock communication during the Canterbury Earthquakes, New Zealand: implications for response and recovery in the built environment

USGS Publications Warehouse

Julia Becker,; Wein, Anne; Sally Potter,; Emma Doyle,; Ratliff, Jamie L.

2015-01-01

On 4 September 2010, a Mw7.1 earthquake occurred in Canterbury, New Zealand. Following the initial earthquake, an aftershock sequence was initiated, with the most significant aftershock being a Mw6.3 earthquake occurring on 22 February 2011. This aftershock caused severe damage to the city of Christchurch and building failures that killed 185 people. During the aftershock sequence it became evident that effective communication of aftershock information (e.g., history and forecasts) was imperative to assist with decision making during the response and recovery phases of the disaster, as well as preparedness for future aftershock events. As a consequence, a joint JCDR-USGS research project was initiated to investigate: • How aftershock information was communicated to organisations and to the public; • How people interpreted that information; • What people did in response to receiving that information; • What information people did and did not need; and • What decision-making challenges were encountered relating to aftershocks. Research was conducted by undertaking focus group meetings and interviews with a range of information providers and users, including scientists and science advisors, emergency managers and responders, engineers, communication officers, businesses, critical infrastructure operators, elected officials, and the public. The interviews and focus group meetings were recorded and transcribed, and key themes were identified. This paper focuses on the aftershock information needs for decision-making about the built environment post-earthquake, including those involved in response (e.g., for building assessment and management), recovery/reduction (e.g., the development of new building standards), and readiness (e.g. between aftershocks). The research has found that the communication of aftershock information varies with time, is contextual, and is affected by interactions among roles, by other information, and by decision objectives. A number

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.

Challenges of Hospital Response to the Twin Earthquakes of August 21, 2012, in East Azerbaijan, Iran.

PubMed

Pouraghaei, Mahboub; Jannati, Ali; Moharamzadeh, Peyman; Ghaffarzad, Amir; Far, Moharram Heshmati; Babaie, Javad

2017-08-01

As the cornerstone of any health system, hospitals have a crucial role in response to disasters. Because hospital experiences in disaster response can be instructive, this study examined the challenges of hospital response to the twin earthquakes of 2012 in East Azerbaijan, Iran. In this qualitative study, the challenges of hospital response in the East Azerbaijan earthquakes were examined through focus group discussions. Participants were selected purposefully, and focus group discussions continued until data saturation. The data were manually analyzed by using Strauss and Corbin's recommended method. Hospitals were faced with 6 major challenges: lack of preparedness, lack of coordination, logistic deficiencies, patient/injured management, communication management, and other smaller challenges that were categorized in the "other challenges" category. The main theme was the lack of preparedness for disasters. Although hospital preparedness is emphasized in credible references, this study showed that lack of preparedness is a major challenge for hospitals during disasters. Thus, it seems that hospital officials' disaster risk perception and hospital preparedness should be improved. In addition, hospital preparedness assessment indexes should be included in the hospital accreditation process. (Disaster Med Public Health Preparedness. 2017;11:422-430).

Behavioral Response in the Immediate Aftermath of Shaking: Earthquakes in Christchurch and Wellington, New Zealand, and Hitachi, Japan

PubMed Central

Jon, Ihnji; Lindell, Michael K.; Prater, Carla S.; Huang, Shih-Kai; Wu, Hao-Che; Johnston, David M.; Becker, Julia S.; Shiroshita, Hideyuki; Doyle, Emma E.H.; Potter, Sally H.; McClure, John; Lambie, Emily

2016-01-01

This study examines people’s response actions in the first 30 min after shaking stopped following earthquakes in Christchurch and Wellington, New Zealand, and Hitachi, Japan. Data collected from 257 respondents in Christchurch, 332 respondents in Hitachi, and 204 respondents in Wellington revealed notable similarities in some response actions immediately after the shaking stopped. In all four events, people were most likely to contact family members and seek additional information about the situation. However, there were notable differences among events in the frequency of resuming previous activities. Actions taken in the first 30 min were weakly related to: demographic variables, earthquake experience, contextual variables, and actions taken during the shaking, but were significantly related to perceived shaking intensity, risk perception and affective responses to the shaking, and damage/infrastructure disruption. These results have important implications for future research and practice because they identify promising avenues for emergency managers to communicate seismic risks and appropriate responses to risk area populations. PMID:27854306

Behavioral Response in the Immediate Aftermath of Shaking: Earthquakes in Christchurch and Wellington, New Zealand, and Hitachi, Japan.

PubMed

Jon, Ihnji; Lindell, Michael K; Prater, Carla S; Huang, Shih-Kai; Wu, Hao-Che; Johnston, David M; Becker, Julia S; Shiroshita, Hideyuki; Doyle, Emma E H; Potter, Sally H; McClure, John; Lambie, Emily

2016-11-15

This study examines people's response actions in the first 30 min after shaking stopped following earthquakes in Christchurch and Wellington, New Zealand, and Hitachi, Japan. Data collected from 257 respondents in Christchurch, 332 respondents in Hitachi, and 204 respondents in Wellington revealed notable similarities in some response actions immediately after the shaking stopped. In all four events, people were most likely to contact family members and seek additional information about the situation. However, there were notable differences among events in the frequency of resuming previous activities. Actions taken in the first 30 min were weakly related to: demographic variables, earthquake experience, contextual variables, and actions taken during the shaking, but were significantly related to perceived shaking intensity, risk perception and affective responses to the shaking, and damage/infrastructure disruption. These results have important implications for future research and practice because they identify promising avenues for emergency managers to communicate seismic risks and appropriate responses to risk area populations.

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

NASA Astrophysics Data System (ADS)

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

2015-12-01

. Earthquake cycle and dynamic rupture models containing deep asperities reproduce the slower spectral decay found in teleseismic spectra of the Gorkha earthquake and in subduction events in the deeper edge of the seismogenic zone.

Characteristics of microearthquakes accompanying hydraulic fracturing as determined from studies of spectra of seismic waveforms

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

Fehler, M.; Bame, D.

1985-03-01

A study of the spectral properties of the waveforms recorded during hydraulic fracturing earthquakes has been carried out to obtain information about the physical dimensions of the earthquakes. We find two types of events. The first type has waveforms with clear P and S arrivals and spectra that are very similar to earthquakes occurring in tectonic regions. These events are interpreted as being due to shear slip along fault planes. The second type of event has waveforms that are similar in many ways to long period earthquakes observed at volcanoes and is called long period. Many waveforms of these eventsmore » are identical, which implies that these events represent repeated activation of a given source. We propose that the source of these long period events is the sudden opening of a channel that connects two cracks filled with fluid at different pressures. The sizes of the two cracks differ, which causes two or more peaks to appear in the spectra, each peak being associated with one physical dimension of the crack. From the frequencies at which spectral peaks occur, we estimate crack dimensions of between 3 and 22m. 13 refs., 8 figs.« less

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.

Leveraging geodetic data to reduce losses from earthquakes

USGS Publications Warehouse

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

2018-04-23

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

Tree seedling response to LED spectra: Implications for forest restoration

Treesearch

Antonio Montagnoli; R. Kasten Dumroese; Mattia Terzaghi; Jeremiah R. Pinto; Nicoletta Fulgaro; Gabriella Stefania Scippa; Donato Chiatante

2018-01-01

We found that different spectra, provided by light-emitting diodes or a fluorescent lamp, caused different photomorphological responses depending on tree seedling type (coniferous or broad-leaved), species, seedling development stage, and seedling fraction (shoot or root). For two conifers (Picea abies and Pinus sylvestris) soon after germination (≤40 days), more...

Source properties of earthquakes near the Salton Sea triggered by the 16 October 1999 M 7.1 Hector Mine, California, earthquake

USGS Publications Warehouse

Hough, S.E.; Kanamori, H.

2002-01-01

We analyze the source properties of a sequence of triggered earthquakes that occurred near the Salton Sea in southern California in the immediate aftermath of the M 7.1 Hector Mine earthquake of 16 October 1999. The sequence produced a number of early events that were not initially located by the regional network, including two moderate earthquakes: the first within 30 sec of the P-wave arrival and a second approximately 10 minutes after the mainshock. We use available amplitude and waveform data from these events to estimate magnitudes to be approximately 4.7 and 4.4, respectively, and to obtain crude estimates of their locations. The sequence of small events following the initial M 4.7 earthquake is clustered and suggestive of a local aftershock sequence. Using both broadband TriNet data and analog data from the Southern California Seismic Network (SCSN), we also investigate the spectral characteristics of the M 4.4 event and other triggered earthquakes using empirical Green's function (EGF) analysis. We find that the source spectra of the events are consistent with expectations for tectonic (brittle shear failure) earthquakes, and infer stress drop values of 0.1 to 6 MPa for six M 2.1 to M 4.4 events. The estimated stress drop values are within the range observed for tectonic earthquakes elsewhere. They are relatively low compared to typically observed stress drop values, which is consistent with expectations for faulting in an extensional, high heat flow regime. The results therefore suggest that, at least in this case, triggered earthquakes are associated with a brittle shear failure mechanism. This further suggests that triggered earthquakes may tend to occur in geothermal-volcanic regions because shear failure occurs at, and can be triggered by, relatively low stresses in extensional regimes.

Forearc deformation and great subduction earthquakes: implications for cascadia offshore earthquake potential.

PubMed

McCaffrey, R; Goldfinger, C

1995-02-10

The maximum size of thrust earthquakes at the world's subduction zones appears to be limited by anelastic deformation of the overriding plate. Anelastic strain in weak forearcs and roughness of the plate interface produced by faults cutting the forearc may limit the size of thrust earthquakes by inhibiting the buildup of elastic strain energy or slip propagation or both. Recently discovered active strike-slip faults in the submarine forearc of the Cascadia subduction zone show that the upper plate there deforms rapidly in response to arc-parallel shear. Thus, Cascadia, as a result of its weak, deforming upper plate, may be the type of subduction zone at which great (moment magnitude approximately 9) thrust earthquakes do not occur.

Source parameters and tectonic interpretation of recent earthquakes (1995 1997) in the Pannonian basin

NASA Astrophysics Data System (ADS)

Badawy, Ahmed; Horváth, Frank; Tóth, László

2001-01-01

From January 1995 to December 1997, about 74 earthquakes were located in the Pannonian basin and digitally recorded by a recently established network of seismological stations in Hungary. On reviewing the notable events, about 12 earthquakes were reported as felt with maximum intensity varying between 4 and 6 MSK. The dynamic source parameters of these earthquakes have been derived from P-wave displacement spectra. The displacement source spectra obtained are characterised by relatively small values of corner frequency ( f0) ranging between 2.5 and 10 Hz. The seismic moments change from 1.48×10 20 to 1.3×10 23 dyne cm, stress drops from 0.25 to 76.75 bar, fault length from 0.42 to 1.7 km and relative displacement from 0.05 to 15.35 cm. The estimated source parameters suggest a good agreement with the scaling law for small earthquakes. The small values of stress drops in the studied earthquakes can be attributed to the low strength of crustal materials in the Pannonian basin. However, the values of stress drops are not different for earthquake with thrust or normal faulting focal mechanism solutions. It can be speculated that an increase of the seismic activity in the Pannonian basin can be predicted in the long run because extensional development ceased and structural inversion is in progress. Seismic hazard assessment is a delicate job due to the inadequate knowledge of the seismo-active faults, particularly in the interior part of the Pannonian basin.

Transportations Systems Modeling and Applications in Earthquake Engineering

DTIC Science & Technology

2010-07-01

49 Figure 6 PGA map of a M7.7 earthquake on all three New Madrid fault segments (g)............... 50...Memphis, Tennessee. The NMSZ was responsible for the devastating 1811-1812 New Madrid earthquakes , the largest earthquakes ever recorded in the...Figure 6 PGA map of a M7.7 earthquake on all three New Madrid fault segments (g) Table 1 Fragility parameters for MSC steel bridge (Padgett 2007

Development and use of a master health facility list: Haiti's experience during the 2010 earthquake response.

PubMed

Rose-Wood, Alyson; Heard, Nathan; Thermidor, Roody; Chan, Jessica; Joseph, Fanor; Lerebours, Gerald; Zugaldia, Antonio; Konkel, Kimberly; Edwards, Michael; Lang, Bill; Torres, Carmen-Rosa

2014-08-01

Master health facility lists (MHFLs) are gaining attention as a standards-based means to uniquely identify health facilities and to link facility-level data. The ability to reliably communicate information about specific health facilities can support an array of health system functions, such as routine reporting and emergency response operations. MHFLs support the alignment of donor-supported health information systems with county-owned systems. Recent World Health Organization draft guidance promotes the utility of MHFLs and outlines a process for list development and governance. Although the potential benefits of MHFLs are numerous and may seem obvious, there are few documented cases of MHFL construction and use. The international response to the 2010 Haiti earthquake provides an example of how governments, nongovernmental organizations, and others can collaborate within a framework of standards to build a more complete and accurate list of health facilities. Prior to the earthquake, the Haitian Ministry of Health (Ministère de la Santé Publique et de la Population [MSPP]) maintained a list of public-sector health facilities but lacked information on privately managed facilities. Following the earthquake, the MSPP worked with a multinational group to expand the completeness and accuracy of the list of health facilities, including information on post-quake operational status. This list later proved useful in the response to the cholera epidemic and is now incorporated into the MSPP's routine health information system. Haiti's experience demonstrates the utility of MHFL formation and use in crisis as well as in the routine function of the health information system.

Development and use of a master health facility list: Haiti's experience during the 2010 earthquake response

PubMed Central

Rose-Wood, Alyson; Heard, Nathan; Thermidor, Roody; Chan, Jessica; Joseph, Fanor; Lerebours, Gerald; Zugaldia, Antonio; Konkel, Kimberly; Edwards, Michael; Lang, Bill; Torres, Carmen-Rosa

2014-01-01

ABSTRACT Master health facility lists (MHFLs) are gaining attention as a standards-based means to uniquely identify health facilities and to link facility-level data. The ability to reliably communicate information about specific health facilities can support an array of health system functions, such as routine reporting and emergency response operations. MHFLs support the alignment of donor-supported health information systems with county-owned systems. Recent World Health Organization draft guidance promotes the utility of MHFLs and outlines a process for list development and governance. Although the potential benefits of MHFLs are numerous and may seem obvious, there are few documented cases of MHFL construction and use. The international response to the 2010 Haiti earthquake provides an example of how governments, nongovernmental organizations, and others can collaborate within a framework of standards to build a more complete and accurate list of health facilities. Prior to the earthquake, the Haitian Ministry of Health (Ministère de la Santé Publique et de la Population [MSPP]) maintained a list of public-sector health facilities but lacked information on privately managed facilities. Following the earthquake, the MSPP worked with a multinational group to expand the completeness and accuracy of the list of health facilities, including information on post-quake operational status. This list later proved useful in the response to the cholera epidemic and is now incorporated into the MSPP's routine health information system. Haiti's experience demonstrates the utility of MHFL formation and use in crisis as well as in the routine function of the health information system. PMID:25276595

Regional propagation characteristics and source parameters of earthquakes in northeastern North America

USGS Publications Warehouse

Boatwright, John

1994-01-01

The vertical components of the S wave trains recorded on the Eastern Canadian Telemetered Network (ECTN) from 1980 through 1990 have been spectrally analyzed for source, site, and propagation characteristics. The data set comprises some 1033 recordings of 97 earthquakes whose magnitudes range from M ≈ 3 to 6. The epicentral distances range from 15 to 1000 km, with most of the data set recorded at distances from 200 to 800 km. The recorded S wave trains contain the phases S, SmS, Sn, and Lg and are sampled using windows that increase with distance; the acceleration spectra were analyzed from 1.0 to 10 Hz. To separate the source, site, and propagation characteristics, an inversion for the earthquake corner frequencies, low-frequency levels, and average attenuation parameters is alternated with a regression of residuals onto the set of stations and a grid of 14 distances ranging from 25 to 1000 km. The iteration between these two parts of the inversion converges in about 60 steps. The average attenuation parameters obtained from the inversion were Q = 1997 ± 10 and γ = 0.998 ± 0.003. The most pronounced variation from this average attenuation is a marked deamplification of more than a factor of 2 at 63 km and 2 Hz, which shallows with increasing frequency and increasing distance out to 200 km. The site-response spectra obtained for the ECTN stations are generally flat. The source spectral shape assumed in this inversion provides an adequate spectral model for the smaller events (Mo < 3 × 1021 dyne-cm) in the data set, whose Brune stress drops range from 5 to 150 bars. For the five events in the data set with Mo ≧ 1023 dyne-cm, however, the source spectra obtained by regressing the residuals suggest that an ω2 spectrum is an inadequate model for the spectral shape. In particular, the corner frequencies for most of these large events appear to be split, so that the spectra exhibit an intermediate behavior (where |ü(ω)| is roughly proportional to ω).

Schoolteachers' Traumatic Experiences and Responses in the Context of a Large-Scale Earthquake in China

ERIC Educational Resources Information Center

Lei, B.

2017-01-01

This article investigates the traumatic experience of teachers who experienced the 2008 earthquake in Sichuan, China. A survey measuring participants' personal experiences, professional demands, and psychological responses was distributed to 241 teachers in five selected schools. Although the status of schoolteachers' trauma in a postdisaster…

The Parkfield earthquake prediction of October 1992; the emergency services response

USGS Publications Warehouse

Andrews, R.

1992-01-01

The science of earthquake prediction is interesting and worthy of support. In many respects the ultimate payoff of earthquake prediction or earthquake forecasting is how the information can be used to enhance public safety and public preparedness. This is a particularly important issue here in California where we have such a high level of seismic risk historically, and currently, as a consequence of activity in 1989 in the San Francisco Bay Area, in Humboldt County in April of this year (1992), and in southern California in the Landers-Big Bear area in late June of this year (1992). We are currently very concerned about the possibility of a major earthquake, one or more, happening close to one of our metropolitan areas. Within that context, the Parkfield experiment becomes very important. 

The California Post-Earthquake Information Clearinghouse: A Plan to Learn From the Next Large California Earthquake

NASA Astrophysics Data System (ADS)

Loyd, R.; Walter, S.; Fenton, J.; Tubbesing, S.; Greene, M.

2008-12-01

In the rush to remove debris after a damaging earthquake, perishable data related to a wide range of impacts on the physical, built and social environments can be lost. The California Post-Earthquake Information Clearinghouse is intended to prevent this data loss by supporting the earth scientists, engineers, and social and policy researchers who will conduct fieldwork in the affected areas in the hours and days following the earthquake to study these effects. First called for by Governor Ronald Reagan following the destructive M6.5 San Fernando earthquake in 1971, the concept of the Clearinghouse has since been incorporated into the response plans of the National Earthquake Hazard Reduction Program (USGS Circular 1242). This presentation is intended to acquaint scientists with the purpose, functions, and services of the Clearinghouse. Typically, the Clearinghouse is set up in the vicinity of the earthquake within 24 hours of the mainshock and is maintained for several days to several weeks. It provides a location where field researchers can assemble to share and discuss their observations, plan and coordinate subsequent field work, and communicate significant findings directly to the emergency responders and to the public through press conferences. As the immediate response effort winds down, the Clearinghouse will ensure that collected data are archived and made available through "lessons learned" reports and publications that follow significant earthquakes. Participants in the quarterly meetings of the Clearinghouse include representatives from state and federal agencies, universities, NGOs and other private groups. Overall management of the Clearinghouse is delegated to the agencies represented by the authors above.

Earthquake Damping Device for Steel Frame

NASA Astrophysics Data System (ADS)

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

2018-04-01

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

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.

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

Stigma in science: the case of earthquake prediction.

PubMed

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

2018-01-01

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

The design and implementation of urban earthquake disaster loss evaluation and emergency response decision support systems based on GIS

NASA Astrophysics Data System (ADS)

Yang, Kun; Xu, Quan-li; Peng, Shuang-yun; Cao, Yan-bo

2008-10-01

Based on the necessity analysis of GIS applications in earthquake disaster prevention, this paper has deeply discussed the spatial integration scheme of urban earthquake disaster loss evaluation models and visualization technologies by using the network development methods such as COM/DCOM, ActiveX and ASP, as well as the spatial database development methods such as OO4O and ArcSDE based on ArcGIS software packages. Meanwhile, according to Software Engineering principles, a solution of Urban Earthquake Emergency Response Decision Support Systems based on GIS technologies have also been proposed, which include the systems logical structures, the technical routes,the system realization methods and function structures etc. Finally, the testing systems user interfaces have also been offered in the paper.

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

Monitoring the Earthquake source process in North America

USGS Publications Warehouse

Herrmann, Robert B.; Benz, H.; Ammon, C.J.

2011-01-01

With the implementation of the USGS National Earthquake Information Center Prompt Assessment of Global Earthquakes for Response system (PAGER), rapid determination of earthquake moment magnitude is essential, especially for earthquakes that are felt within the contiguous United States. We report an implementation of moment tensor processing for application to broad, seismically active areas of North America. This effort focuses on the selection of regional crustal velocity models, codification of data quality tests, and the development of procedures for rapid computation of the seismic moment tensor. We systematically apply these techniques to earthquakes with reported magnitude greater than 3.5 in continental North America that are not associated with a tectonic plate boundary. Using the 0.02-0.10 Hz passband, we can usually determine, with few exceptions, moment tensor solutions for earthquakes with M w as small as 3.7. The threshold is significantly influenced by the density of stations, the location of the earthquake relative to the seismic stations and, of course, the signal-to-noise ratio. With the existing permanent broadband stations in North America operated for rapid earthquake response, the seismic moment tensor of most earthquakes that are M w 4 or larger can be routinely computed. As expected the nonuniform spatial pattern of these solutions reflects the seismicity pattern. However, the orientation of the direction of maximum compressive stress and the predominant style of faulting is spatially coherent across large regions of the continent.

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

NASA Astrophysics Data System (ADS)

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

2012-10-01

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

HF Doppler observations of acoustic waves excited by the earthquake

NASA Technical Reports Server (NTRS)

Ichinose, T.; Takagi, K.; Tanaka, T.; Okuzawa, T.; Shibata, T.; Sato, Y.; Nagasawa, C.; Ogawa, T.

1985-01-01

Ionospheric disturbances caused by the earthquake of a relatively small and large epicentral distance have been detected by a network of HF-Doppler sounders in central Japan and Kyoto station, respectively. The HF-Doppler data of a small epicentral distance, together with the seismic data, have been used to formulate a mechanism whereby ionospheric disturbances are produced by the Urakawa-Oki earthquake in Japan. Comparison of the dynamic spectra of these data has revealed experimentally that the atmosphere acts as a low-pass filter for upward-propagating acoustic waves. By surveying the earthquakes for which the magnitude M is larger than 6.0, researchers found the ionospheric effect in 16 cases of 82 seismic events. As almost all these effects have occurred in the daytime, it is considered that it may result from the filtering effect of the upward-propagating acoustic waves.

Plasma turbulence in the ionosphere prior to earthquakes, some remarks on the DEMETER registrations

NASA Astrophysics Data System (ADS)

Błęcki, Jan; Parrot, Michel; Wronowski, Roman

2011-06-01

The question about presence of some precursors of the earthquakes has a long history. The answer is still not resolved, but researchers are looking for the effects which can be registered prior to earthquakes. One of the factors which has been found is the variation of the electromagnetic field observed on ground as well as onboard satellites. The disturbances of the electromagnetic field around areas of the earthquakes as pre-seismic events can occur few hours or even few days before the main shock. The payload of the DEMETER French microsatellite allows to measure waves and also some important plasma parameters (ion composition, electron density and temperature, energetic particles) with high temporal resolution in the ionosphere over the seismic regions. In the present work, analysis of the low frequency fluctuations of the electric fields for selected strong earthquakes in Japan (2004), China (2008), Taiwan (2006) and New Zealand (2009) are given. Special attention will be given to the study of the spectral characteristics of these variations and the search for nonlinear effects. This analysis is possible in the time interval where the waveform has been transmitted. The mechanism of the energy transmission from earthquakes to the ionosphere is not clear, but we can discuss the behavior of the ionospheric plasma and the search for instabilities which could be a source of electromagnetic field variations. A brief discussion of the characteristics of the spectra and multi-spectra is given in this paper. Attention is particularly given to the effect prior to the earthquake in New Zealand, when a nonlinear interaction leading to a lower hybrid wave generation was directly seen.

Rapid Response Products of The ARIA Project for the M6.0 August 24, 2014 South Napa Earthquake

NASA Astrophysics Data System (ADS)

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

2014-12-01

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

Earthquakes

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... 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 ...

Nonlinear ionospheric responses to large-amplitude infrasonic-acoustic waves generated by undersea earthquakes

NASA Astrophysics Data System (ADS)

Zettergren, M. D.; Snively, J. B.; Komjathy, A.; Verkhoglyadova, O. P.

2017-02-01

Numerical models of ionospheric coupling with the neutral atmosphere are used to investigate perturbations of plasma density, vertically integrated total electron content (TEC), neutral velocity, and neutral temperature associated with large-amplitude acoustic waves generated by the initial ocean surface displacements from strong undersea earthquakes. A simplified source model for the 2011 Tohoku earthquake is constructed from estimates of initial ocean surface responses to approximate the vertical motions over realistic spatial and temporal scales. Resulting TEC perturbations from modeling case studies appear consistent with observational data, reproducing pronounced TEC depletions which are shown to be a consequence of the impacts of nonlinear, dissipating acoustic waves. Thermospheric acoustic compressional velocities are ˜±250-300 m/s, superposed with downward flows of similar amplitudes, and temperature perturbations are ˜300 K, while the dominant wave periodicity in the thermosphere is ˜3-4 min. Results capture acoustic wave processes including reflection, onset of resonance, and nonlinear steepening and dissipation—ultimately leading to the formation of ionospheric TEC depletions "holes"—that are consistent with reported observations. Three additional simulations illustrate the dependence of atmospheric acoustic wave and subsequent ionospheric responses on the surface displacement amplitude, which is varied from the Tohoku case study by factors of 1/100, 1/10, and 2. Collectively, results suggest that TEC depletions may only accompany very-large amplitude thermospheric acoustic waves necessary to induce a nonlinear response, here with saturated compressional velocities ˜200-250 m/s generated by sea surface displacements exceeding ˜1 m occurring over a 3 min time period.

Money matters: Rapid post-earthquake financial decision-making

USGS Publications Warehouse

Wald, David J.; Franco, Guillermo

2016-01-01

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

Slip model and Synthetic Broad-band Strong Motions for the 2015 Mw 8.3 Illapel (Chile) Earthquake.

NASA Astrophysics Data System (ADS)

Aguirre, P.; Fortuno, C.; de la Llera, J. C.

2017-12-01

The MW 8.3 earthquake that occurred on September 16th 2015 west of Illapel, Chile, ruptured a 200 km section of the plate boundary between 29º S and 33º S. SAR data acquired by the Sentinel 1A satellite was used to obtain the interferogram of the earthquake, and from it, the component of the displacement field of the surface in the line of sight of the satellite. Based on this interferogram, the corresponding coseismic slip distribution for the earthquake was determined based on different plausible finite fault geometries. The model that best fits the data gathered is one whose rupture surface is consistent with the Slab 1.0 model, with a constant strike angle of 4º and variable dip angle ranging from 2.7º near the trench to 24.3º down dip. Using this geometry the maximum slip obtained is 7.52 m and the corresponding seismic moment is 3.78·1021 equivalent to a moment magnitude Mw 8.3. Calculation of the Coulomb failure stress change induced by this slip distribution evidences a strong correlation between regions where stress is increased as consequence of the earthquake, and the occurrence of the most relevant aftershocks, providing a consistency check for the inversion procedure applied and its results.The finite fault model for the Illapel earthquake is used to test a hybrid methodology for generation of synthetic ground motions that combines a deterministic calculation of the low frequency content, with stochastic modelling of the high frequency signal. Strong ground motions are estimated at the location of seismic stations recording the Illapel earthquake. Such simulations include the effect of local soil conditions, which are modelled empirically based on H/V ratios obtained from a large database of historical seismic records. Comparison of observed and synthetic records based on the 5%-damped response spectra yield satisfactory results for locations where the site response function is more robustly estimated.

Long-term responses of sandy beach crustaceans to the effects of coastal armouring after the 2010 Maule earthquake in South Central Chile

NASA Astrophysics Data System (ADS)

Rodil, Iván F.; Jaramillo, Eduardo; Acuña, Emilio; Manzano, Mario; Velasquez, Carlos

2016-02-01

Earthquakes and tsunamis are large physical disturbances frequently striking the coast of Chile with dramatic effects on intertidal habitats. Armouring structures built as societal responses to beach erosion and shoreline retreat are also responsible of coastal squeeze and habitat loss. The ecological implications of interactions between coastal armouring and earthquakes have recently started to be studied for beach ecosystems. How long interactive impacts persist is still unclear because monitoring after disturbance generally extends for a few months. During five years after the Maule earthquake (South Central Chile, February 27th 2010) we monitored the variability in population abundances of the most common crustacean inhabitants of different beach zones (i.e. upper, medium, and lower intertidal) at two armoured (one concrete seawall and one rocky revetment) and one unarmoured sites along the sandy beach of Llico. Beach morphology changed after the earthquake-mediated uplift, restoring upper- and mid-shore armoured levels that were rapidly colonized by typical crustacean species. However, post-earthquake increasing human activities affected the colonization process of sandy beach crustaceans in front of the seawall. Lower-shore crab Emerita analoga was the less affected by armouring structures, and it was the only crustacean species present at the three sites before and after the earthquake. This study shows that field sampling carried out promptly after major disturbances, and monitoring of the affected sites long after the disturbance is gone are effective approaches to increase the knowledge on the interactive effects of large-scale natural phenomena and artificial defences on beach ecology.

Earthquake education in California

USGS Publications Warehouse

MacCabe, M. P.

1980-01-01

In a survey of community response to the earthquake threat in southern California, Ralph Turner and his colleagues in the Department of Sociology at the University of California, Los Angeles, found that the public very definitely wants to be educated about the kinds of problems and hazards they can expect during and after a damaging earthquake; and they also want to know how they can prepare themselves to minimize their vulnerability. Decisionmakers, too, are recognizing this new wave of public concern. 

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.

Modeling the poroelastic response to megathrust earthquakes: A look at the 2012 Mw 7.6 Costa Rican event

NASA Astrophysics Data System (ADS)

McCormack, Kimberly A.; Hesse, Marc A.

2018-04-01

We model the subsurface hydrologic response to the 7.6 Mw subduction zone earthquake that occurred on the plate interface beneath the Nicoya peninsula in Costa Rica on September 5, 2012. The regional-scale poroelastic model of the overlying plate integrates seismologic, geodetic and hydrologic data sets to predict the post-seismic poroelastic response. A representative two-dimensional model shows that thrust earthquakes with a slip width less than a third of their depth produce complex multi-lobed pressure perturbations in the shallow subsurface. This leads to multiple poroelastic relaxation timescales that may overlap with the longer viscoelastic timescales. In the three-dimensional model, the complex slip distribution of 2012 Nicoya event and its small width to depth ratio lead to a pore pressure distribution comprising multiple trench parallel ridges of high and low pressure. This leads to complex groundwater flow patterns, non-monotonic variations in predicted well water levels, and poroelastic relaxation on multiple time scales. The model also predicts significant tectonically driven submarine groundwater discharge off-shore. In the weeks following the earthquake, the predicted net submarine groundwater discharge in the study area increases, creating a 100 fold increase in net discharge relative to topography-driven flow over the first 30 days. Our model suggests the hydrological response on land is more complex than typically acknowledged in tectonic studies. This may complicate the interpretation of transient post-seismic surface deformations. Combined tectonic-hydrological observation networks have the potential to reduce such ambiguities.

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

NASA Astrophysics Data System (ADS)

Hutchinson, Lauren; Stead, Doug; Rosser, Nick

2017-04-01

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

Earthquake Response of Reinforced Concrete Building Retrofitted with Geopolymer Concrete and X-shaped Metallic Damper

NASA Astrophysics Data System (ADS)

Madheswaran, C. K.; Prakash vel, J.; Sathishkumar, K.; Rao, G. V. Rama

2017-06-01

A three-storey half scale reinforced concrete (RC) building is fixed with X-shaped metallic damper at the ground floor level, is designed and fabricated to study its seismic response characteristics. Experimental studies are carried out using the (4 m × 4 m) tri-axial shake-table facility to evaluate the seismic response of a retrofitted RC building with open ground storey (OGS) structure using yielding type X-shaped metallic dampers (also called as Added Damping and Stiffness-ADAS elements) and repairing the damaged ground storey columns using geopolymer concrete composites. This elasto-plastic device is normally incorporated within the frame structure between adjacent floors through chevron bracing, so that they efficiently enhance the overall energy dissipation ability of the seismically deficient frame structure under earthquake loading. Free vibration tests on RC building without and with yielding type X-shaped metallic damper is carried out. The natural frequencies and mode shapes of RC building without and with yielding type X-shaped metallic damper are determined. The retrofitted reinforced concrete building is subjected to earthquake excitations and the response from the structure is recorded. This work discusses the preparation of test specimen, experimental set-up, instrumentation, method of testing of RC building and the response of the structure. The metallic damper reduces the time period of the structure and displacement demands on the OGS columns of the structure. Nonlinear time history analysis is performed using structural analysis package, SAP2000.

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)

PAGER - Rapid Assessment of an Earthquake's Impact

USGS Publications Warehouse

Earle, Paul S.; Wald, David J.

2007-01-01

PAGER (Prompt Assessment of Global Earthquakes for Response) is an automated system to rapidly assess the number of people and regions exposed to severe shaking by an earthquake, and inform emergency responders, government agencies, and the media to the scope of the potential disaster. PAGER monitors the U.S. Geological Survey?s near real-time U.S. and global earthquake detections and automatically identifies events that are of societal importance, well in advance of ground-truth or news accounts.

Prospective testing of Coulomb short-term earthquake forecasts

NASA Astrophysics Data System (ADS)

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

2009-12-01

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

Response of Water Levels in Devils Hole, Death Valley National Park, Nevada, to Atmospheric Loading, Earth Tides, and Earthquakes

NASA Astrophysics Data System (ADS)

Cutillo, P. A.; Ge, S.

2004-12-01

Devils Hole, home to the endangered Devils Hole pupfish (Cyprinodon diabolis) in Death Valley National Park, Nevada, is one of about 30 springs and the largest collapse depression in the Ash Meadows area. The small pool leads to an extensive subterranean cavern within the regional Paleozoic carbonate-rock aquifer. Previous work has established that the pool level fluctuates in response to changes in barometric pressure, Earth tides and earthquakes. Analyses of these fluctuations indicate that the formation is a sensitive indicator of crustal strain, and provide important information regarding the material properties of the surrounding aquifer. Over ten years of hourly water-level measurements were analyzed for the effects of atmospheric loading and Earth tides. The short-term water-level fluctuations caused by these effects were found to be on the order of millimeters to centimeters, indicating relatively low matrix compressibility. Accordingly, the Devils Hole water-level record shows strong responses to the June 28, 1992 Landers/Little Skull Mountain earthquake sequence and to the October 16, 1999 Hector Mine earthquake. A dislocation model was used to calculate volumetric strain for each earthquake. The sensitivity of Devils Hole to strain induced by the solid Earth tide was used to constrain the modeling. Water-level decreases observed following the 1992 and 1999 earthquakes were found to be consistent with areas of crustal expansion predicted by the dislocation model. The magnitude of the water-level changes was also found to be proportional to the predicted coseismic volumetric strain. Post-seismic pore-pressure diffusion, governed by the hydraulic diffusivity of the aquifer, was simulated with a numerical model using the coseismic change in pore pressure as an initial condition. Results of the numerical model indicate that factors such as fault-plane geometry and aquifer heterogeneity may play an important role in controlling pore pressure diffusion in the

Modelling low-frequency volcanic earthquakes in a viscoelastic medium with topography

NASA Astrophysics Data System (ADS)

Jousset, Philippe; Neuberg, Jürgen; Jolly, Arthur

2004-11-01

Magma properties are fundamental to explain the volcanic eruption style as well as the generation and propagation of seismic waves. This study focusses on magma properties and rheology and their impact on low-frequency volcanic earthquakes. We investigate the effects of anelasticity and topography on the amplitudes and spectra of synthetic low-frequency earthquakes. Using a 2-D finite-difference scheme, we model the propagation of seismic energy initiated in a fluid-filled conduit embedded in a homogeneous viscoelastic medium with topography. We model intrinsic attenuation by linear viscoelastic theory and we show that volcanic media can be approximated by a standard linear solid (SLS) for seismic frequencies above 2 Hz. Results demonstrate that attenuation modifies both amplitudes and dispersive characteristics of low-frequency earthquakes. Low frequency volcanic earthquakes are dispersive by nature; however, if attenuation is introduced, their dispersion characteristics will be altered. The topography modifies the amplitudes, depending on the position of the seismographs at the surface. This study shows that we need to take into account attenuation and topography to interpret correctly observed low-frequency volcanic earthquakes. It also suggests that the rheological properties of magmas may be constrained by the analysis of low-frequency seismograms.

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.

Stochastic strong ground motion simulations for the intermediate-depth earthquakes of the south Aegean subduction zone

NASA Astrophysics Data System (ADS)

Kkallas, Harris; Papazachos, Konstantinos; Boore, David; Margaris, Vasilis

2015-04-01

We have employed the stochastic finite-fault modelling approach of Motazedian and Atkinson (2005), as described by Boore (2009), for the simulation of Fourier spectra of the Intermediate-depth earthquakes of the south Aegean subduction zone. The stochastic finite-fault method is a practical tool for simulating ground motions of future earthquakes which requires region-specific source, path and site characterizations as input model parameters. For this reason we have used data from both acceleration-sensor and broadband velocity-sensor instruments from intermediate-depth earthquakes with magnitude of M 4.5-6.7 that occurred in the south Aegean subduction zone. Source mechanisms for intermediate-depth events of north Aegean subduction zone are either collected from published information or are constrained using the main faulting types from Kkallas et al. (2013). The attenuation parameters for simulations were adopted from Skarladoudis et al. (2013) and are based on regression analysis of a response spectra database. The site amplification functions for each soil class were adopted from Klimis et al., (1999), while the kappa values were constrained from the analysis of the EGELADOS network data from Ventouzi et al., (2013). The investigation of stress-drop values was based on simulations performed with the EXSIM code for several ranges of stress drop values and by comparing the results with the available Fourier spectra of intermediate-depth earthquakes. Significant differences regarding the strong-motion duration, which is determined from Husid plots (Husid, 1969), have been identified between the for-arc and along-arc stations due to the effect of the low-velocity/low-Q mantle wedge on the seismic wave propagation. In order to estimate appropriate values for the duration of P-waves, we have automatically picked P-S durations on the available seismograms. For the S-wave durations we have used the part of the seismograms starting from the S-arrivals and ending at the

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…

The Pacific Tsunami Warning Center's Response to the Tohoku Earthquake and Tsunami

NASA Astrophysics Data System (ADS)

Weinstein, S. A.; Becker, N. C.; Shiro, B.; Koyanagi, K. K.; Sardina, V.; Walsh, D.; Wang, D.; McCreery, C. S.; Fryer, G. J.; Cessaro, R. K.; Hirshorn, B. F.; Hsu, V.

2011-12-01

The largest Pacific basin earthquake in 47 years, and also the largest magnitude earthquake since the Sumatra 2004 earthquake, struck off of the east coast of the Tohoku region of Honshu, Japan at 5:46 UTC on 11 March 2011. The Tohoku earthquake (Mw 9.0) generated a massive tsunami with runups of up to 40m along the Tohoku coast. The tsunami waves crossed the Pacific Ocean causing significant damage as far away as Hawaii, California, and Chile, thereby becoming the largest, most destructive tsunami in the Pacific Basin since 1960. Triggers on the seismic stations at Erimo, Hokkaido (ERM) and Matsushiro, Honshu (MAJO), alerted Pacific Tsunami Warning Center (PTWC) scientists 90 seconds after the earthquake began. Four minutes after its origin, and about one minute after the earthquake's rupture ended, PTWC issued an observatory message reporting a preliminary magnitude of 7.5. Eight minutes after origin time, the Japan Meteorological Agency (JMA) issued its first international tsunami message in its capacity as the Northwest Pacific Tsunami Advisory Center. In accordance with international tsunami warning system protocols, PTWC then followed with its first international tsunami warning message using JMA's earthquake parameters, including an Mw of 7.8. Additional Mwp, mantle wave, and W-phase magnitude estimations based on the analysis of later-arriving seismic data at PTWC revealed that the earthquake magnitude reached at least 8.8, and that a destructive tsunami would likely be crossing the Pacific Ocean. The earthquake damaged the nearest coastal sea-level station located 90 km from the epicenter in Ofunato, Japan. The NOAA DART sensor situated 600 km off the coast of Sendai, Japan, at a depth of 5.6 km recorded a tsunami wave amplitude of nearly two meters, making it by far the largest tsunami wave ever recorded by a DART sensor. Thirty minutes later, a coastal sea-level station at Hanasaki, Japan, 600 km from the epicenter, recorded a tsunami wave amplitude of

Incertitude in disaster sciences and scientists' responsibilities: A case study of the L'Aquila earthquake trial

NASA Astrophysics Data System (ADS)

Koketsu, Kazuki; Oki, Satoko

2015-04-01

What disaster sciences are expected by the society is to prevent or mitigate future natural disasters, and therefore it is necessary to foresee natural disasters. However, various constraints often make the foreseeing difficult so that there is a high incertitude in the social contribution of disaster sciences. If scientists overstep this limitation, they will be held even criminally responsible. The L'Aquila trial in Italy is such a recent example and so we have performed data collections, hearing investigations, analyses of the reasons for the initial court's judgment, etc., to explore the incertitude of disaster sciences and scientists' responsibilities. As a result, we concluded that the casualties during the L'Aquila earthquake were mainly due to a careless "safety declaration" by the vice-director of the Civil Protection Agency, where the incertitude of disaster sciences had never been considered. In addition, news media which reported only this "safety declaration" were also seriously responsible for the casualties. The accused other than the vice-director were only morally responsible, because their meeting remarks included poor risk communication in disaster sciences but those were not reported to the citizens in advance to the L'Aquila earthquake. In the presentation, we will also discuss the similarities and differences between our conclusions above and the reasons for the appeals court's judgement, which will be published in February.

A revised “earthquake report” questionaire

USGS Publications Warehouse

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

1976-01-01

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

Local tsunamis and earthquake source parameters

USGS Publications Warehouse

Geist, Eric L.; Dmowska, Renata; Saltzman, Barry

1999-01-01

This chapter establishes the relationship among earthquake source parameters and the generation, propagation, and run-up of local tsunamis. In general terms, displacement of the seafloor during the earthquake rupture is modeled using the elastic dislocation theory for which the displacement field is dependent on the slip distribution, fault geometry, and the elastic response and properties of the medium. Specifically, nonlinear long-wave theory governs the propagation and run-up of tsunamis. A parametric study is devised to examine the relative importance of individual earthquake source parameters on local tsunamis, because the physics that describes tsunamis from generation through run-up is complex. Analysis of the source parameters of various tsunamigenic earthquakes have indicated that the details of the earthquake source, namely, nonuniform distribution of slip along the fault plane, have a significant effect on the local tsunami run-up. Numerical methods have been developed to address the realistic bathymetric and shoreline conditions. The accuracy of determining the run-up on shore is directly dependent on the source parameters of the earthquake, which provide the initial conditions used for the hydrodynamic models.

A New Simplified Source Model to Explain Strong Ground Motions from a Mega-Thrust Earthquake - Application to the 2011 Tohoku Earthquake (Mw9.0) -

NASA Astrophysics Data System (ADS)

Nozu, A.

2013-12-01

A new simplified source model is proposed to explain strong ground motions from a mega-thrust earthquake. The proposed model is simpler, and involves less model parameters, than the conventional characterized source model, which itself is a simplified expression of actual earthquake source. In the proposed model, the spacio-temporal distribution of slip within a subevent is not modeled. Instead, the source spectrum associated with the rupture of a subevent is modeled and it is assumed to follow the omega-square model. By multiplying the source spectrum with the path effect and the site amplification factor, the Fourier amplitude at a target site can be obtained. Then, combining it with Fourier phase characteristics of a smaller event, the time history of strong ground motions from the subevent can be calculated. Finally, by summing up contributions from the subevents, strong ground motions from the entire rupture can be obtained. The source model consists of six parameters for each subevent, namely, longitude, latitude, depth, rupture time, seismic moment and corner frequency of the subevent. Finite size of the subevent can be taken into account in the model, because the corner frequency of the subevent is included in the model, which is inversely proportional to the length of the subevent. Thus, the proposed model is referred to as the 'pseudo point-source model'. To examine the applicability of the model, a pseudo point-source model was developed for the 2011 Tohoku earthquake. The model comprises nine subevents, located off Miyagi Prefecture through Ibaraki Prefecture. The velocity waveforms (0.2-1 Hz), the velocity envelopes (0.2-10 Hz) and the Fourier spectra (0.2-10 Hz) at 15 sites calculated with the pseudo point-source model agree well with the observed ones, indicating the applicability of the model. Then the results were compared with the results of a super-asperity (SPGA) model of the same earthquake (Nozu, 2012, AGU), which can be considered as an

A Hybrid Ground-Motion Prediction Equation for Earthquakes in Western Alberta

NASA Astrophysics Data System (ADS)

Spriggs, N.; Yenier, E.; Law, A.; Moores, A. O.

2015-12-01

Estimation of ground-motion amplitudes that may be produced by future earthquakes constitutes the foundation of seismic hazard assessment and earthquake-resistant structural design. This is typically done by using a prediction equation that quantifies amplitudes as a function of key seismological variables such as magnitude, distance and site condition. In this study, we develop a hybrid empirical prediction equation for earthquakes in western Alberta, where evaluation of seismic hazard associated with induced seismicity is of particular interest. We use peak ground motions and response spectra from recorded seismic events to model the regional source and attenuation attributes. The available empirical data is limited in the magnitude range of engineering interest (M>4). Therefore, we combine empirical data with a simulation-based model in order to obtain seismologically informed predictions for moderate-to-large magnitude events. The methodology is two-fold. First, we investigate the shape of geometrical spreading in Alberta. We supplement the seismic data with ground motions obtained from mining/quarry blasts, in order to gain insights into the regional attenuation over a wide distance range. A comparison of ground-motion amplitudes for earthquakes and mining/quarry blasts show that both event types decay at similar rates with distance and demonstrate a significant Moho-bounce effect. In the second stage, we calibrate the source and attenuation parameters of a simulation-based prediction equation to match the available amplitude data from seismic events. We model the geometrical spreading using a trilinear function with attenuation rates obtained from the first stage, and calculate coefficients of anelastic attenuation and site amplification via regression analysis. This provides a hybrid ground-motion prediction equation that is calibrated for observed motions in western Alberta and is applicable to moderate-to-large magnitude events.

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.

Fault healing promotes high-frequency earthquakes in laboratory experiments and on natural faults

USGS Publications Warehouse

McLaskey, Gregory C.; Thomas, Amanda M.; Glaser, Steven D.; Nadeau, Robert M.

2012-01-01

Faults strengthen or heal with time in stationary contact and this healing may be an essential ingredient for the generation of earthquakes. In the laboratory, healing is thought to be the result of thermally activated mechanisms that weld together micrometre-sized asperity contacts on the fault surface, but the relationship between laboratory measures of fault healing and the seismically observable properties of earthquakes is at present not well defined. Here we report on laboratory experiments and seismological observations that show how the spectral properties of earthquakes vary as a function of fault healing time. In the laboratory, we find that increased healing causes a disproportionately large amount of high-frequency seismic radiation to be produced during fault rupture. We observe a similar connection between earthquake spectra and recurrence time for repeating earthquake sequences on natural faults. Healing rates depend on pressure, temperature and mineralogy, so the connection between seismicity and healing may help to explain recent observations of large megathrust earthquakes which indicate that energetic, high-frequency seismic radiation originates from locations that are distinct from the geodetically inferred locations of large-amplitude fault slip

GIS Based System for Post-Earthquake Crisis Managment Using Cellular Network

NASA Astrophysics Data System (ADS)

Raeesi, M.; Sadeghi-Niaraki, A.

2013-09-01

Earthquakes are among the most destructive natural disasters. Earthquakes happen mainly near the edges of tectonic plates, but they may happen just about anywhere. Earthquakes cannot be predicted. Quick response after disasters, like earthquake, decreases loss of life and costs. Massive earthquakes often cause structures to collapse, trapping victims under dense rubble for long periods of time. After the earthquake and destroyed some areas, several teams are sent to find the location of the destroyed areas. The search and rescue phase usually is maintained for many days. Time reduction for surviving people is very important. A Geographical Information System (GIS) can be used for decreasing response time and management in critical situations. Position estimation in short period of time time is important. This paper proposes a GIS based system for post-earthquake disaster management solution. This system relies on several mobile positioning methods such as cell-ID and TA method, signal strength method, angel of arrival method, time of arrival method and time difference of arrival method. For quick positioning, the system can be helped by any person who has a mobile device. After positioning and specifying the critical points, the points are sent to a central site for managing the procedure of quick response for helping. This solution establishes a quick way to manage the post-earthquake crisis.

Detector-Response Correction of Two-Dimensional γ -Ray Spectra from Neutron Capture

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

Rusev, G.; Jandel, M.; Arnold, C. W.

2015-05-28

The neutron-capture reaction produces a large variety of γ-ray cascades with different γ-ray multiplicities. A measured spectral distribution of these cascades for each γ-ray multiplicity is of importance to applications and studies of γ-ray statistical properties. The DANCE array, a 4π ball of 160 BaF 2 detectors, is an ideal tool for measurement of neutron-capture γ-rays. The high granularity of DANCE enables measurements of high-multiplicity γ-ray cascades. The measured two-dimensional spectra (γ-ray energy, γ-ray multiplicity) have to be corrected for the DANCE detector response in order to compare them with predictions of the statistical model or use them in applications.more » The detector-response correction problem becomes more difficult for a 4π detection system than for a single detector. A trial and error approach and an iterative decomposition of γ-ray multiplets, have been successfully applied to the detector-response correction. As a result, applications of the decomposition methods are discussed for two-dimensional γ-ray spectra measured at DANCE from γ-ray sources and from the 10B(n, γ) and 113Cd(n, γ) reactions.« less

Large Earthquakes Disrupt Groundwater System by Breaching Aquitards

NASA Astrophysics Data System (ADS)

Wang, C. Y.; Manga, M.; Liao, X.; Wang, L. P.

2016-12-01

Changes of groundwater system by large earthquakes are widely recognized. Some changes have been attributed to increases in the vertical permeability but basic questions remain: How do increases in the vertical permeability occur? How frequent do they occur? How fast does the vertical permeability recover after the earthquake? Is there a quantitative measure for detecting the occurrence of aquitard breaching? Here we attempt to answer these questions by examining data accumulated in the past 15 years. Analyses of increased stream discharges and their geochemistry after large earthquakes show evidence that the excess water originates from groundwater released from high elevations by large increase of the vertical permeability. Water-level data from a dense network of clustered wells in a sedimentary basin near the epicenter of the 1999 M7.6 Chi-Chi earthquake in western Taiwan show that, while most confined aquifers remained confined after the earthquake, about 10% of the clustered wells show evidence of coseismic breaching of aquitards and a great increase of the vertical permeability. Water level in wells without evidence of coseismic breaching of aquitards show similar tidal response before and after the earthquake; wells with evidence of coseismic breaching of aquitards, on the other hand, show distinctly different tidal response before and after the earthquake and that the aquifers became hydraulically connected for many months thereafter. Breaching of aquitards by large earthquakes has significant implications for a number of societal issues such as the safety of water resources, the security of underground waste repositories, and the production of oil and gas. The method demonstrated here may be used for detecting the occurrence of aquitard breaching by large earthquakes in other seismically active areas.

Earthquake and ambient vibration monitoring of the steel-frame UCLA factor building

USGS Publications Warehouse

Kohler, M.D.; Davis, P.M.; Safak, E.

2005-01-01

Dynamic property measurements of the moment-resisting steel-frame University of California, Los Angeles, Factor building are being made to assess how forces are distributed over the building. Fourier amplitude spectra have been calculated from several intervals of ambient vibrations, a 24-hour period of strong winds, and from the 28 March 2003 Encino, California (ML = 2.9), the 3 September 2002 Yorba Linda, California (ML = 4.7), and the 3 November 2002 Central Alaska (Mw = 7.9) earthquakes. Measurements made from the ambient vibration records show that the first-mode frequency of horizontal vibration is between 0.55 and 0.6 Hz. The second horizontal mode has a frequency between 1.6 and 1.9 Hz. In contrast, the first-mode frequencies measured from earthquake data are about 0.05 to 0.1 Hz lower than those corresponding to ambient vibration recordings indicating softening of the soil-structure system as amplitudes become larger. The frequencies revert to pre-earthquake levels within five minutes of the Yorba Linda earthquake. Shaking due to strong winds that occurred during the Encino earthquake dominates the frequency decrease, which correlates in time with the duration of the strong winds. The first shear wave recorded from the Encino and Yorba Linda earthquakes takes about 0.4 sec to travel up the 17-story building. ?? 2005, Earthquake Engineering Research Institute.

Earthquake Ground Motion Selection

DOT National Transportation Integrated Search

2012-05-01

Nonlinear analyses of soils, structures, and soil-structure systems offer the potential for more accurate characterization of geotechnical and structural response under strong earthquake shaking. The increasing use of advanced performance-based desig...

Near-Fault Strong Ground Motions during the 2016 Kumamoto, Japan, Earthquake

NASA Astrophysics Data System (ADS)

Iwata, T.; Asano, K.

2016-12-01

The 2016 Kumamoto mainshock (Mw7.0) produced a surface ruptured fault of about 20km long with maximum 2m offset, and identified as a surface ruptured event. Two strong motion records were observed near the surface ruptured fault at Mashiki town hall and Nishihara village hall. We investigated characteristics of those strong ground motions. As the acceleration records consisted of the baseline errors caused by nonzero initial acceleration and tilting of the accelerograph, we carefully removed the baseline errors (c.f. Chiu, 2001, Boore and Bommer, 2005) so as to obtain velocity and displacements. The observed permanent displacements were about 1.2m in horizontal direction and about 0.7m sinking in vertical direction at Mashiki town hall, and about 1.7m and 1.8m, respectively, at Nishihara village hall. Those permanent displacements almost coincide to results by GNSS and InSAR analysis (e.g., GSI, 2016). It takes about only 3 s to reach the permanent displacement. Somerville (2003) pointed out that ground motions from earthquakes producing large surface ruptures appeared to have systematically weaker ground motions than ground motions from earthquakes whose rupture were confined to the subsurface using the Ground Motion Prediction Equation (GMPE) for response spectra (Abrahamson and Silva, 1997). We calculated the response spectra of those records, compared them to the GMPE with the same manner and found two records were systematically larger than the expected from the GMPE in the period range of 0.3 s to 5 s. We need to re-consider the working hypothesis that the near-fault ground motions are weaker and to separate the near-fault and site effects on ground motions. Strong motions in the longer period range would be mainly caused by the near-fault (near-field term) effect.We used the acceleration data of the Kumamoto seismic intensity information network, provided by JMA.

Complex earthquake rupture and local tsunamis

USGS Publications Warehouse

Geist, E.L.

2002-01-01

In contrast to far-field tsunami amplitudes that are fairly well predicted by the seismic moment of subduction zone earthquakes, there exists significant variation in the scaling of local tsunami amplitude with respect to seismic moment. From a global catalog of tsunami runup observations this variability is greatest for the most frequently occuring tsunamigenic subduction zone earthquakes in the magnitude range of 7 < Mw < 8.5. Variability in local tsunami runup scaling can be ascribed to tsunami source parameters that are independent of seismic moment: variations in the water depth in the source region, the combination of higher slip and lower shear modulus at shallow depth, and rupture complexity in the form of heterogeneous slip distribution patterns. The focus of this study is on the effect that rupture complexity has on the local tsunami wave field. A wide range of slip distribution patterns are generated using a stochastic, self-affine source model that is consistent with the falloff of far-field seismic displacement spectra at high frequencies. The synthetic slip distributions generated by the stochastic source model are discretized and the vertical displacement fields from point source elastic dislocation expressions are superimposed to compute the coseismic vertical displacement field. For shallow subduction zone earthquakes it is demonstrated that self-affine irregularities of the slip distribution result in significant variations in local tsunami amplitude. The effects of rupture complexity are less pronounced for earthquakes at greater depth or along faults with steep dip angles. For a test region along the Pacific coast of central Mexico, peak nearshore tsunami amplitude is calculated for a large number (N = 100) of synthetic slip distribution patterns, all with identical seismic moment (Mw = 8.1). Analysis of the results indicates that for earthquakes of a fixed location, geometry, and seismic moment, peak nearshore tsunami amplitude can vary by a

The changing health priorities of earthquake response and implications for preparedness: a scoping review.

PubMed

Cartwright, C; Hall, M; Lee, A C K

2017-09-01

Earthquakes have substantial impacts on mortality in low- and middle-income countries (LMIC). The academic evidence base to support Disaster Risk Reduction activities in LMIC settings is, however, limited. We sought to address this gap by identifying the health and healthcare impacts of earthquakes in LMICs and to identify the implications of these findings for future earthquake preparedness. Scoping review. A scoping review was undertaken with systematic searches of indexed databases to identify relevant literature. Key study details, findings, recommendations or lessons learnt were extracted and analysed across individual earthquake events. Findings were categorised by time frame relative to earthquakes and linked to the disaster preparedness cycle, enabling a profile of health and healthcare impacts and implications for future preparedness to be established. Health services need to prepare for changing health priorities with a shift from initial treatment of earthquake-related injuries to more general health needs occurring within the first few weeks. Preparedness is required to address mental health and rehabilitation needs in the medium to longer term. Inequalities of the impact of earthquakes on health were noted in particular for women, children, the elderly, disabled and rural communities. The need to maintain access to essential services such as reproductive health and preventative health services were identified. Key preparedness actions include identification of appropriate leaders, planning and training of staff. Testing of plans was advocated within the literature with evidence that this is possible in LMIC settings. Whilst there are a range of health and healthcare impacts of earthquakes, common themes emerged in different settings and from different earthquake events. Preparedness of healthcare systems is essential and possible, in order to mitigate the adverse health impacts of earthquakes in LMIC settings. Preparedness is needed at the community

Low-frequency source parameters of twelve large earthquakes. M.S. Thesis

NASA Technical Reports Server (NTRS)

Harabaglia, Paolo

1993-01-01

A global survey of the low-frequency (1-21 mHz) source characteristics of large events are studied. We are particularly interested in events unusually enriched in low-frequency and in events with a short-term precursor. We model the source time function of 12 large earthquakes using teleseismic data at low frequency. For each event we retrieve the source amplitude spectrum in the frequency range between 1 and 21 mHz with the Silver and Jordan method and the phase-shift spectrum in the frequency range between 1 and 11 mHz with the Riedesel and Jordan method. We then model the source time function by fitting the two spectra. Two of these events, the 1980 Irpinia, Italy, and the 1983 Akita-Oki, Japan, are shallow-depth complex events that took place on multiple faults. In both cases the source time function has a length of about 100 seconds. By comparison Westaway and Jackson find 45 seconds for the Irpinia event and Houston and Kanamori about 50 seconds for the Akita-Oki earthquake. The three deep events and four of the seven intermediate-depth events are fast rupturing earthquakes. A single pulse is sufficient to model the source spectra in the frequency range of our interest. Two other intermediate-depth events have slower rupturing processes, characterized by a continuous energy release lasting for about 40 seconds. The last event is the intermediate-depth 1983 Peru-Ecuador earthquake. It was first recognized as a precursive event by Jordan. We model it with a smooth rupturing process starting about 2 minutes before the high frequency origin time superimposed to an impulsive source.

New perspectives on self-similarity for shallow thrust earthquakes

NASA Astrophysics Data System (ADS)

Denolle, Marine A.; Shearer, Peter M.

2016-09-01

Scaling of dynamic rupture processes from small to large earthquakes is critical to seismic hazard assessment. Large subduction earthquakes are typically remote, and we mostly rely on teleseismic body waves to extract information on their slip rate functions. We estimate the P wave source spectra of 942 thrust earthquakes of magnitude Mw 5.5 and above by carefully removing wave propagation effects (geometrical spreading, attenuation, and free surface effects). The conventional spectral model of a single-corner frequency and high-frequency falloff rate does not explain our data, and we instead introduce a double-corner-frequency model, modified from the Haskell propagating source model, with an intermediate falloff of f-1. The first corner frequency f1 relates closely to the source duration T1, its scaling follows M0∝T13 for Mw<7.5, and changes to M0∝T12 for larger earthquakes. An elliptical rupture geometry better explains the observed scaling than circular crack models. The second time scale T2 varies more weakly with moment, M0∝T25, varies weakly with depth, and can be interpreted either as expressions of starting and stopping phases, as a pulse-like rupture, or a dynamic weakening process. Estimated stress drops and scaled energy (ratio of radiated energy over seismic moment) are both invariant with seismic moment. However, the observed earthquakes are not self-similar because their source geometry and spectral shapes vary with earthquake size. We find and map global variations of these source parameters.

The enigmatic Bala earthquake of 1974

NASA Astrophysics Data System (ADS)

Musson, R. M. W.

2006-10-01

The earthquake that shook most of North Wales on the night of 23 January 1974 appears unremarkable from its entry in the UK earthquake catalogue. With a magnitude of 3.5 ML it represents the size of earthquake to be expected in the UK with a return period of about one year. However, the prominent atmospheric lights observed at the time of the shock led to speculation that an aircraft had crashed, and search-and-rescue teams were deployed. Since nothing was discovered, it was concluded that a meteorite was responsible; more imaginative members of the public decided (and still believe) that a UFO had crashed. In this paper the record of events is set out, and the nature of the earthquake is discussed with reference to its geological setting.

The U.S. Military Response to the 2010 Haiti Earthquake: Considerations for Army Leaders

DTIC Science & Technology

2013-01-01

responsible for Haiti’s geographic region. Table 1.1 The World’s 15 Deadliest Natural Disasters Since 1900 Disaster Death Tolla Year Country Yangtze ...200,000 1927 China Great Kanto earthquake 143,000 1923 Japan Yangtze River flood 140,000 1935 China Cyclone Nargis 100,000–138,000 2008 Burma...100,000 1971 North Vietnam Yangtze flood 100,000 1911 China SOURCES: “The World’s Worst Natural Disasters,” 2010; USGS, 2012. NOTE: This list does not

Unfolding neutron spectra from simulated response of thermoluminescence dosimeters inside a polyethylene sphere using GRNN neural network

NASA Astrophysics Data System (ADS)

Lotfalizadeh, F.; Faghihi, R.; Bahadorzadeh, B.; Sina, S.

2017-07-01

Neutron spectrometry using a single-sphere containing dosimeters has been developed recently, as an effective replacement for Bonner sphere spectrometry. The aim of this study is unfolding the neutron energy spectra using GRNN artificial neural network, from the response of thermoluminescence dosimeters, TLDs, located inside a polyethylene sphere. The spectrometer was simulated using MCNP5. TLD-600 and TLD-700 dosimeters were simulated at different positions in all directions. Then the GRNN was used for neutron spectra prediction, using the TLDs' readings. Comparison of spectra predicted by the network with the real spectra, show that the single-sphere dosimeter is an effective instrument in unfolding neutron spectra.

Recorded earthquake responses from the integrated seismic monitoring network of the Atwood Building, Anchorage, Alaska

USGS Publications Warehouse

Celebi, M.

2006-01-01

An integrated seismic monitoring system with a total of 53 channels of accelerometers is now operating in and at the nearby free-field site of the 20-story steel-framed Atwood Building in highly seismic Anchorage, Alaska. The building has a single-story basement and a reinforced concrete foundation without piles. The monitoring system comprises a 32-channel structural array and a 21-channel site array. Accelerometers are deployed on 10 levels of the building to assess translational, torsional, and rocking motions, interstory drift (displacement) between selected pairs of adjacent floors, and average drift between floors. The site array, located approximately a city block from the building, comprises seven triaxial accelerometers, one at the surface and six in boreholes ranging in depths from 15 to 200 feet (???5-60 meters). The arrays have already recorded low-amplitude shaking responses of the building and the site caused by numerous earthquakes at distances ranging from tens to a couple of hundred kilometers. Data from an earthquake that occurred 186 km away traces the propagation of waves from the deepest borehole to the roof of the building in approximately 0.5 seconds. Fundamental structural frequencies [0.58 Hz (NS) and 0.47 Hz (EW)], low damping percentages (2-4%), mode coupling, and beating effects are identified. The fundamental site frequency at approximately 1.5 Hz is close to the second modal frequencies (1.83 Hz NS and 1.43 EW) of the building, which may cause resonance of the building. Additional earthquakes prove repeatability of these characteristics; however, stronger shaking may alter these conclusions. ?? 2006, Earthquake Engineering Research Institute.

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

NASA Astrophysics Data System (ADS)

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

2014-05-01

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

Atmosphere-Ionosphere Response to the M9 Tohoku Earthquake Revealed by Multi-Instrument Space-Borne and Ground Observations. Preliminary Results

NASA Technical Reports Server (NTRS)

Ouzounov, Dimitar; Pulinets, Sergey; Romanov, Alexey; Romanov, Alexander; Tsbulya, Konstantin; Davidenko, Dmitri; Kafatos, Menas; Taylor, Patrick

2011-01-01

We retrospectively analyzed the temporal and spatial variations of four different physical parameters characterizing the state of the atmosphere and ionosphere several days before the M9 Tohoku Japan earthquake of March 11, 2011. Data include outgoing long wave radiation (OLR), GPS/TEC, Low-Earth orbit ionospheric tomography and critical frequency foF2. Our first results show that on March 8th a rapid increase of emitted infrared radiation was observed from the satellite data and an anomaly developed near the epicenter. The GPS/TEC data indicate an increase and variation in electron density reaching a maximum value on March 8. Starting on this day in the lower ionospheric there was also confirmed an abnormal TEC variation over the epicenter. From March 3-11 a large increase in electron concentration was recorded at all four Japanese ground based ionosondes, which returned to normal after the main earthquake The joined preliminary analysis of atmospheric and ionospheric parameters during the M9 Tohoku Japan earthquake has revealed the presence of related variations of these parameters implying their connection with the earthquake process. This study may lead to a better understanding of the response of the atmosphere/ionosphere to the Great Tohoku earthquake.

Continuous Record of Permeability inside the Wenchuan Earthquake Fault Zone

NASA Astrophysics Data System (ADS)

Xue, Lian; Li, Haibing; Brodsky, Emily

2013-04-01

Faults are complex hydrogeological structures which include a highly permeable damage zone with fracture-dominated permeability. Since fractures are generated by earthquakes, we would expect that in the aftermath of a large earthquake, the permeability would be transiently high in a fault zone. Over time, the permeability may recover due to a combination of chemical and mechanical processes. However, the in situ fault zone hydrological properties are difficult to measure and have never been directly constrained on a fault zone immediately after a large earthquake. In this work, we use water level response to solid Earth tides to constrain the hydraulic properties inside the Wenchuan Earthquake Fault Zone. The transmissivity and storage determine the phase and amplitude response of the water level to the tidal loading. By measuring phase and amplitude response, we can constrain the average hydraulic properties of the damage zone at 800-1200 m below the surface (~200-600 m from the principal slip zone). We use Markov chain Monte Carlo methods to evaluate the phase and amplitude responses and the corresponding errors for the largest semidiurnal Earth tide M2 in the time domain. The average phase lag is ~ 30o, and the average amplitude response is 6×10-7 strain/m. Assuming an isotropic, homogenous and laterally extensive aquifer, the average storage coefficient S is 2×10-4 and the average transmissivity T is 6×10-7 m2 using the measured phase and the amplitude response. Calculation for the hydraulic diffusivity D with D=T/S, yields the reported value of D is 3×10-3 m2/s, which is two orders of magnitude larger than pump test values on the Chelungpu Fault which is the site of the Mw 7.6 Chi-Chi earthquake. If the value is representative of the fault zone, then this means the hydrology processes should have an effect on the earthquake rupture process. This measurement is done through continuous monitoring and we could track the evolution for hydraulic properties

Precursory earthquakes of the 1943 eruption of Paricutin volcano, Michoacan, Mexico

NASA Astrophysics Data System (ADS)

Yokoyama, I.; de la Cruz-Reyna, S.

1990-12-01

Paricutin volcano is a monogenetic volcano whose birth and growth were observed by modern volcanological techniques. At the time of its birth in 1943, the seismic activity in central Mexico was mainly recorded by the Wiechert seismographs at the Tacubaya seismic station in Mexico City about 320 km east of the volcano area. In this paper we aim to find any characteristics of precursory earthquakes of the monogenetic eruption. Though there are limits in the available information, such as imprecise location of hypocenters and lack of earthquake data with magnitudes under 3.0. The available data show that the first precursory earthquake occurred on January 7, 1943, with a magnitude of 4.4. Subsequently, 21 earthquakes ranging from 3.2 to 4.5 in magnitude occurred before the outbreak of the eruption on February 20. The (S - P) durations of the precursory earthquakes do not show any systematic changes within the observational errors. The hypocenters were rather shallow and did not migrate. The precursory earthquakes had a characteristic tectonic signature, which was retained through the whole period of activity. However, the spectra of the P-waves of the Paricutin earthquakes show minor differences from those of tectonic earthquakes. This fact helped in the identification of Paricutin earthquakes. Except for the first shock, the maximum earthquake magnitudes show an increasing tendency with time towards the outbreak. The total seismic energy released by the precursory earthquakes amounted to 2 × 10 19 ergs. Considering that statistically there is a threshold of cumulative seismic energy release (10 17-18ergs) by precursory earthquakes in polygenetic volcanoes erupting after long quiescence, the above cumulative energy is exceptionally large. This suggests that a monogenetic volcano may need much more energy to clear the way of magma passage to the earth surface than a polygenetic one. The magma ascent before the outbreak of Paricutin volcano is interpretable by a model

GeoMO 2008--geotechnical earthquake engineering : site response.

DOT National Transportation Integrated Search

2008-10-01

The theme of GeoMO2008 has recently become of more interest to the Midwest civil engineering community due to the perceived earthquake risks and new code requirements. The constant seismic reminder for the New Madrid Seismic Zone and new USGS hazard ...

An atlas of ShakeMaps for selected global earthquakes

USGS Publications Warehouse

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

2008-01-01

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

IR spectral analysis for the diagnostics of crust earthquake precursors

NASA Astrophysics Data System (ADS)

Umarkhodgaev, R. M.; Liperovsky, V. A.; Mikhailin, V. V.; Meister, C.-V.; Naumov, D. Ju

2012-04-01

In regions of future earthquakes, a few days before the seismic shock, the emanation of radon and hydrogen is being observed, which causes clouds of increased ionisation in the atmosphere. In the present work the possible diagnostics of these clouds using infrared (IR) spectroscopy is considered, which may be important and useful for the general geophysical system of earthquake prediction and the observation of industrial emissions of radioactive materials into the atmosphere. Some possible physical processes are analysed, which cause, under the condition of additional ionisation in a pre-breakdown electrical field, emissions in the IR interval. In doing so, the transparency region of the IR spectrum at wavelengths of 7-15 μm is taken into account. This transparency region corresponds to spectral lines of small atmospheric constituents like CH4, CO2, N2O, NO2, NO, and O3. The possible intensities of the IR emissions observable in laboratories and in nature are estimated. The acceleration process of the electrons in the pre-breakdown electrical field before its adhesion to the molecules is analysed. The laboratory equipment for the investigation of the IR absorption spectrum is constructed for the cases of normal and decreased atmospheric pressures. The syntheses of ozone and nitrous oxides are performed in the barrier discharge. It is studied if the products of the syntheses may be used to model atmospheric processes where these components take part. Spectra of products of the syntheses in the wavelength region of 2-10 μm are observed and analysed. A device is created for the syntheses and accumulation of nitrous oxides. Experiments to observe the IR-spectra of ozone and nitrous oxides during the syntheses and during the further evolution of these molecules are performed. For the earthquake prediction, practically, the investigation of emission spectra is most important, but during the laboratory experiments, the radiation of the excited molecules is shifted by a

Validation of Broadband Ground Motion Simulations for Japanese Crustal Earthquakes by the Recipe

NASA Astrophysics Data System (ADS)

Iwaki, A.; Maeda, T.; Morikawa, N.; Miyake, H.; Fujiwara, H.

2015-12-01

The Headquarters for Earthquake Research Promotion (HERP) of Japan has organized the broadband ground motion simulation method into a standard procedure called the "recipe" (HERP, 2009). In the recipe, the source rupture is represented by the characterized source model (Irikura and Miyake, 2011). The broadband ground motion time histories are computed by a hybrid approach: the 3-D finite-difference method (Aoi et al. 2004) and the stochastic Green's function method (Dan and Sato, 1998; Dan et al. 2000) for the long- (> 1　s) and short-period (< 1 s) components, respectively, using the 3-D velocity structure model. As the engineering significance of scenario earthquake ground motion prediction is increasing, thorough verification and validation are required for the simulation methods. This study presents the self-validation of the recipe for two MW6.6 crustal events in Japan, the 2000 Tottori and 2004 Chuetsu (Niigata) earthquakes. We first compare the simulated velocity time series with the observation. Main features of the velocity waveforms, such as the near-fault pulses and the large later phases on deep sediment sites are well reproduced by the simulations. Then we evaluate 5% damped pseudo acceleration spectra (PSA) in the framework of the SCEC Broadband Platform (BBP) validation (Dreger et al. 2015). The validation results are generally acceptable in the period range 0.1 - 10 s, whereas those in the shortest period range (0.01-0.1 s) are less satisfactory. We also evaluate the simulations with the 1-D velocity structure models used in the SCEC BBP validation exercise. Although the goodness-of-fit parameters for PSA do not significantly differ from those for the 3-D velocity structure model, noticeable differences in velocity waveforms are observed. Our results suggest the importance of 1) well-constrained 3-D velocity structure model for broadband ground motion simulations and 2) evaluation of time series of ground motion as well as response spectra.

Earthquake response of storey building in Jakarta using accelerographs data analysis

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

Julius, Admiral Musa, E-mail: admiralmusajulius@yahoo.com; Jakarta Geophysics Observatory, Indonesia Agency of Meteorology Climatology and Geophysics; Sunardi, Bambang, E-mail: b.sunardi@gmail.com

As seismotectonic, the Jakarta city will be greatly affected by the earthquake which originated from the subduction zone of the Sunda Strait and south of Java. Some occurrences of earthquakes in these location are often perceived by the occupants in the upper floors of multi-storey buildings in Jakarta but was not perceived by the occupants on the ground floor. The case shows the difference in ground-motion parameters on each floor height. The analysis of the earthquake data recorded by accelerographs on different floors need to be done to know the differences in ground-motion parameters. Data used in this research ismore » accelerograph data installed on several floors in the main building of Meteorology Climatology and Geophysics Agency with a case study of Kebumen earthquake on January 25{sup th} 2014. Parameters analyzed include the Peak Ground Acceleration (PGA), Peak Ground Displacement (PGD), Peak Spectral Acceleration (PSA), Amplification (Ag), and the Effective Duration of earthquake (t{sub e}). Research stages include accelerographs data acquisition in three (3) different floors, conversion and data partition for each component, conversion to units of acceleration, determination of PGA, PGD, PSA, Ag and t{sub e} as well as data analysis. The study shows the value of PGA on the ground floor, 7{sup th} floor and 15{sup th} floors, respectively are 0.016 g, 0.053 g and 0.116 g. PGD on the ground floor, 7{sup th} floor and 15{sup th} floor respectively are 2.15 cm, 2.98 cm and 4.92 cm. PSA on the ground floor, 7{sup th} floor and 15{sup th} floor respectively are 0.067 g, 0.308 g and 0.836 g. Amplification of the peak acceleration value on the ground floor, 7{sup th} floor and 15{sup th} floor to the surface rock are 4.37, 6.07 and 7.30. Effective duration of the earthquake on the ground floor, 7{sup th} floor and 15{sup th} floor respectively are 222.28 s, 202.28 s and 91.58 s. In general, with increasing floor of the building, the value

The 2004 Parkfield, CA Earthquake: A Teachable Moment for Exploring Earthquake Processes, Probability, and Earthquake Prediction

NASA Astrophysics Data System (ADS)

Kafka, A.; Barnett, M.; Ebel, J.; Bellegarde, H.; Campbell, L.

2004-12-01

The occurrence of the 2004 Parkfield earthquake provided a unique "teachable moment" for students in our science course for teacher education majors. The course uses seismology as a medium for teaching a wide variety of science topics appropriate for future teachers. The 2004 Parkfield earthquake occurred just 15 minutes after our students completed a lab on earthquake processes and earthquake prediction. That lab included a discussion of the Parkfield Earthquake Prediction Experiment as a motivation for the exercises they were working on that day. Furthermore, this earthquake was recorded on an AS1 seismograph right in their lab, just minutes after the students left. About an hour after we recorded the earthquake, the students were able to see their own seismogram of the event in the lecture part of the course, which provided an excellent teachable moment for a lecture/discussion on how the occurrence of the 2004 Parkfield earthquake might affect seismologists' ideas about earthquake prediction. The specific lab exercise that the students were working on just before we recorded this earthquake was a "sliding block" experiment that simulates earthquakes in the classroom. The experimental apparatus includes a flat board on top of which are blocks of wood attached to a bungee cord and a string wrapped around a hand crank. Plate motion is modeled by slowly turning the crank, and earthquakes are modeled as events in which the block slips ("blockquakes"). We scaled the earthquake data and the blockquake data (using how much the string moved as a proxy for time) so that we could compare blockquakes and earthquakes. This provided an opportunity to use interevent-time histograms to teach about earthquake processes, probability, and earthquake prediction, and to compare earthquake sequences with blockquake sequences. We were able to show the students, using data obtained directly from their own lab, how global earthquake data fit a Poisson exponential distribution better

Effect of repeated earthquake on inelastic moment resisting concrete frame

NASA Astrophysics Data System (ADS)

Tahara, R. M. K.; Majid, T. A.; Zaini, S. S.; Faisal, A.

2017-10-01

This paper investigates the response of inelastic moment resisting concrete building under repeated earthquakes. 2D models consist of 3-storey, 6-storey and 9-storey representing low to medium rise building frame were designed using seismic load and ductility class medium (DCM) according to the requirements set by Euro Code 8. Behaviour factor and stiffness degradation were also taken into consideration. Seven sets of real repeated earthquakes as opposed to artificial earthquakes data were used. The response of the frame was measured in terms of the inter-storey drift and maximum displacement. By adopting repeated earthquake, the recorded mean IDR increased in the range of 3% - 21%. Similarly, in the case of maximum displacement, the values also increased from 20 mm to 40 mm. The findings concluded that the effect of using repeated earthquake in seismic analysis considerably influenced the inter-storey drift and the maximum displacement.

Stress/strain changes and triggered seismicity following the MW7.3 Landers, California, earthquake

USGS Publications Warehouse

Gomberg, J.

1996-01-01

Calculations of dynamic stresses and strains, constrained by broadband seismograms, are used to investigate their role in generating the remotely triggered seismicity that followed the June 28, 1992, MW7.3 Landers, California earthquake. I compare straingrams and dynamic Coulomb failure functions calculated for the Landers earthquake at sites that did experience triggered seismicity with those at sites that did not. Bounds on triggering thresholds are obtained from analysis of dynamic strain spectra calculated for the Landers and MW,6.1 Joshua Tree, California, earthquakes at various sites, combined with results of static strain investigations by others. I interpret three principal results of this study with those of a companion study by Gomberg and Davis [this issue]. First, the dynamic elastic stress changes themselves cannot explain the spatial distribution of triggered seismicity, particularly the lack of triggered activity along the San Andreas fault system. In addition to the requirement to exceed a Coulomb failure stress level, this result implies the need to invoke and satisfy the requirements of appropriate slip instability theory. Second, results of this study are consistent with the existence of frequency- or rate-dependent stress/strain triggering thresholds, inferred from the companion study and interpreted in terms of earthquake initiation involving a competition of processes, one promoting failure and the other inhibiting it. Such competition is also part of relevant instability theories. Third, the triggering threshold must vary from site to site, suggesting that the potential for triggering strongly depends on site characteristics and response. The lack of triggering along the San Andreas fault system may be correlated with the advanced maturity of its fault gouge zone; the strains from the Landers earthquake were either insufficient to exceed its larger critical slip distance or some other critical failure parameter; or the faults failed stably as

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.

The origin of high frequency radiation in earthquakes and the geometry of faulting

NASA Astrophysics Data System (ADS)

Madariaga, R.

2004-12-01

In a seminal paper of 1967 Kei Aki discovered the scaling law of earthquake spectra and showed that, among other things, the high frequency decay was of type omega-squared. This implies that high frequency displacement amplitudes are proportional to a characteristic length of the fault, and radiated energy scales with the cube of the fault dimension, just like seismic moment. Later in the seventies, it was found out that a simple explanation for this frequency dependence of spectra was that high frequencies were generated by stopping phases, waves emitted by changes in speed of the rupture front as it propagates along the fault, but this did not explain the scaling of high frequency waves with fault length. Earthquake energy balance is such that, ignoring attenuation, radiated energy is the change in strain energy minus energy released for overcoming friction. Until recently the latter was considered to be a material property that did not scale with fault size. Yet, in another classical paper Aki and Das estimated in the late 70s that energy release rate also scaled with earthquake size, because earthquakes were often stopped by barriers or changed rupture speed at them. This observation was independently confirmed in the late 90s by Ide and Takeo and Olsen et al who found that energy release rates for Kobe and Landers were in the order of a MJ/m2, implying that Gc necessarily scales with earthquake size, because if this was a material property, small earthquakes would never occur. Using both simple analytical and numerical models developed by Addia-Bedia and Aochi and Madariaga, we examine the consequence of these observations for the scaling of high frequency waves with fault size. We demonstrate using some classical results by Kostrov, Husseiny and Freund that high frequency energy flow measures energy release rate and is generated when ruptures change velocity (both direction and speed) at fault kinks or jogs. Our results explain why super shear ruptures are

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 ...

High-frequency ground motion amplification during the 2011 Tohoku earthquake explained by soil dilatancy

NASA Astrophysics Data System (ADS)

Roten, D.; Fäh, D.; Bonilla, L. F.

2013-05-01

Ground motions of the 2011 Tohoku earthquake recorded at Onahama port (Iwaki, Fukushima prefecture) rank among the highest accelerations ever observed, with the peak amplitude of the 3-D acceleration vector approaching 2g. The response of the site was distinctively non-linear, as indicated by the presence of horizontal acceleration spikes which have been linked to cyclic mobility during similar observations. Compared to records of weak ground motions, the response of the site during the Mw 9.1 earthquake was characterized by increased amplification at frequencies above 10 Hz and in peak ground acceleration. This behaviour contrasts with the more common non-linear response encountered at non-liquefiable sites, which results in deamplification at higher frequencies. We simulate propagation of SH waves through the dense sand deposit using a non-linear finite difference code that is capable of modelling the development of excess pore water pressure. Dynamic soil parameters are calibrated using a direct search method that minimizes the difference between observed and simulated acceleration envelopes and response spectra. The finite difference simulations yield surface acceleration time-series that are consistent with the observations in shape and amplitude, pointing towards soil dilatancy as a likely explanation for the high-frequency pulses recorded at Onahama port. The simulations also suggest that the occurrence of high-frequency spikes coincided with a rapid increase in pore water pressure in the upper part of the sand deposit between 145 and 170 s. This sudden increase is possibly linked to a burst of high-frequency energy from a large slip patch below the Iwaki region.

Evidences of landslide earthquake triggering due to self-excitation process

NASA Astrophysics Data System (ADS)

Bozzano, F.; Lenti, L.; Martino, Salvatore; Paciello, A.; Scarascia Mugnozza, G.

2011-06-01

The basin-like setting of stiff bedrock combined with pre-existing landslide masses can contribute to seismic amplifications in a wide frequency range (0-10 Hz) and induce a self-excitation process responsible for earthquake-triggered landsliding. Here, the self-excitation process is proposed to justify the far-field seismic trigger of the Cerda landslide (Sicily, Italy) which was reactivated by the 6th September 2002 Palermo earthquake ( M s = 5.4), about 50 km far from the epicentre. The landslide caused damage to farm houses, roads and aqueducts, close to the village of Cerda, and involved about 40 × 106 m3 of clay shales; the first ground cracks due to the landslide movement formed about 30 min after the main shock. A stress-strain dynamic numerical modelling, performed by FDM code FLAC 5.0, supports the notion that the combination of local geological setting and earthquake frequency content played a fundamental role in the landslide reactivation. Since accelerometric records of the triggering event are not available, dynamic equivalent inputs have been used for the numerical modelling. These inputs can be regarded as representative for the local ground shaking, having a PGA value up to 0.2 m/s2, which is the maximum expected in 475 years, according to the Italian seismic hazard maps. A 2D numerical modelling of the seismic wave propagation in the Cerda landslide area was also performed; it pointed out amplification effects due to both the structural setting of the stiff bedrock (at about 1 Hz) and the pre-existing landslide mass (in the range 3-6 Hz). The frequency peaks of the resulting amplification functions ( A( f)) fit well the H/ V spectral ratios from ambient noise and the H/ H spectral ratios to a reference station from earthquake records, obtained by in situ velocimetric measurements. Moreover, the Fourier spectra of earthquake accelerometric records, whose source and magnitude are consistent with the triggering event, show a main peak at about 1 Hz

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

PubMed

Raccanello, Daniela; Burro, Roberto; Hall, Rob

2017-01-01

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

Simple nonlinear modelling of earthquake response in torsionally coupled R/C structures: A preliminary study

NASA Astrophysics Data System (ADS)

Saiidi, M.

1982-07-01

The equivalent of a single degree of freedom (SDOF) nonlinear model, the Q-model-13, was examined. The study intended to: (1) determine the seismic response of a torsionally coupled building based on the multidegree of freedom (MDOF) and (SDOF) nonlinear models; and (2) develop a simple SDOF nonlinear model to calculate displacement history of structures with eccentric centers of mass and stiffness. It is shown that planar models are able to yield qualitative estimates of the response of the building. The model is used to estimate the response of a hypothetical six-story frame wall reinforced concrete building with torsional coupling, using two different earthquake intensities. It is shown that the Q-Model-13 can lead to a satisfactory estimate of the response of the structure in both cases.

USGS response to an urban earthquake, Northridge '94

USGS Publications Warehouse

Updike, Randall G.; Brown, William M.; Johnson, Margo L.; Omdahl, Eleanor M.; Powers, Philip S.; Rhea, Susan; Tarr, Arthur C.

1996-01-01

For the past 2 years, the USGS has rigorously pursued over 40 tasks focused on the USGS Northridge Earthquake Mission. This document is a summary report of the USGS findings; additional technical reports on specific USGS tasks are appearing in various scientific journals and USGS publications.

The October 1992 Parkfield, California, earthquake prediction

USGS Publications Warehouse

Langbein, J.

1992-01-01

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

Earthquake triggering at alaskan volcanoes following the 3 November 2002 denali fault earthquake

USGS Publications Warehouse

Moran, S.C.; Power, J.A.; Stihler, S.D.; Sanchez, J.J.; Caplan-Auerbach, J.

2004-01-01

The 3 November 2002 Mw 7.9 Denali fault earthquake provided an excellent opportunity to investigate triggered earthquakes at Alaskan volcanoes. The Alaska Volcano Observatory operates short-period seismic networks on 24 historically active volcanoes in Alaska, 247-2159 km distant from the mainshock epicenter. We searched for evidence of triggered seismicity by examining the unfiltered waveforms for all stations in each volcano network for ???1 hr after the Mw 7.9 arrival time at each network and for significant increases in located earthquakes in the hours after the mainshock. We found compelling evidence for triggering only at the Katmai volcanic cluster (KVC, 720-755 km southwest of the epicenter), where small earthquakes with distinct P and 5 arrivals appeared within the mainshock coda at one station and a small increase in located earthquakes occurred for several hours after the mainshock. Peak dynamic stresses of ???0.1 MPa at Augustine Volcano (560 km southwest of the epicenter) are significantly lower than those recorded in Yellowstone and Utah (>3000 km southeast of the epicenter), suggesting that strong directivity effects were at least partly responsible for the lack of triggering at Alaskan volcanoes. We describe other incidents of earthquake-induced triggering in the KVC, and outline a qualitative magnitude/distance-dependent triggering threshold. We argue that triggering results from the perturbation of magmatic-hydrothermal systems in the KVC and suggest that the comparative lack of triggering at other Alaskan volcanoes could be a result of differences in the nature of magmatic-hydrothermal systems.

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.

Defining "Acceptable Risk" for Earthquakes Worldwide

NASA Astrophysics Data System (ADS)

Tucker, B.

2001-05-01

results suggest that the comparisons of the participating cities are easily understood, and defensible. The evaluation of the sources of El Salvador's risk, made before the January 13th earthquake, pointed to the vulnerability made visible by the earthquake: earthquake-induced landslides, and difficulties with emergency response.

Networks in disasters: Multidisciplinary communication and coordination in response and recovery to the 2010 Haiti Earthquake (Invited)

NASA Astrophysics Data System (ADS)

McAdoo, B. G.; Augenstein, J.; Comfort, L.; Huggins, L.; Krenitsky, N.; Scheinert, S.; Serrant, T.; Siciliano, M.; Stebbins, S.; Sweeney, P.; University Of Pittsburgh Haiti Reconnaissance Team

2010-12-01

The 12 January 2010 earthquake in Haiti demonstrates the necessity of understanding information communication between disciplines during disasters. Armed with data from a variety of sources, from geophysics to construction, water and sanitation to education, decision makers can initiate well-informed policies to reduce the risk from future hazards. At the core of this disaster was a natural hazard that occurred in an environmentally compromised country. The earthquake itself was not solely responsible for the magnitude of the disaster- poor construction practices precipitated by extreme poverty, a two centuries of post-colonial environmental degradation and a history of dysfunctional government shoulder much of the responsibility. Future policies must take into account the geophysical reality that future hazards are inevitable and may occur within the very near future, and how various institutions will respond to the stressors. As the global community comes together in reconstruction efforts, it is necessary for the various actors to take into account what vulnerabilities were exposed by the earthquake, most vividly seen during the initial response to the disaster. Responders are forced to prioritize resources designated for building collapse and infrastructure damage, delivery of critical services such as emergency medical care, and delivery of food and water to those in need. Past disasters have shown that communication lapses between the response and recovery phases results in many of the exposed vulnerabilities not being adequately addressed, and the recovery hence fails to bolster compromised systems. The response reflects the basic characteristics of a Complex Adaptive System, where new agents emerge and priorities within existing organizations shift to deal with new information. To better understand how information is shared between actors during this critical transition, we are documenting how information is communicated between critical sectors during the

Failure behavior of concrete pile and super-structure dynamic response as a result of soil liquefaction during earthquake

NASA Astrophysics Data System (ADS)

Kaneda, Shogo; Hayashi, Kazuhiro; Hachimori, Wataru; Tamura, Shuji; Saito, Taiki

2017-10-01

In past earthquake disasters, numerous building structure piles were damaged by soil liquefaction occurring during the earthquake. Damage to these piles, because they are underground, is difficult to find. The authors aim to develop a monitoring method of pile damage based on superstructure dynamic response. This paper investigated the relationship between the damage of large cross section cementitious piles and the dynamic response of the super structure using a centrifuge test apparatus. A dynamic specimen used simple cross section pile models consisting of aluminum rod and mortar, a saturated soil (Toyoura sand) of a relative density of 40% and a super structure model of a natural period of 0.63sec. In the shaking table test under a 50G field (length scale of 1/50), excitation was a total of 3 motions scaled from the Rinkai wave at different amplitudes. The maximum acceleration of each of the excitations was 602gal, 336gal and 299gal. The centrifuge test demonstrated the liquefaction of saturated soil and the failure behavior of piles. In the test result, the damage of piles affected the predominant period of acceleration response spectrum on the footing of the superstructure.

The extent of soft tissue and musculoskeletal injuries after earthquakes; describing a role for reconstructive surgeons in an emergency response.

PubMed

Clover, A J P; Jemec, B; Redmond, A D

2014-10-01

Earthquakes are the leading cause of natural disaster-related mortality and morbidity. Soft tissue and musculoskeletal injuries are the predominant type of injury seen after these events and a major reason for admission to hospital. Open fractures are relatively common; however, they are resource-intense to manage. Appropriate management is important in minimising amputation rates and preserving function. This review describes the pattern of musculoskeletal and soft-tissue injuries seen after earthquakes and explores the manpower and resource implications involved in their management. A Medline search was performed, including terms "injury pattern" and "earthquake," "epidemiology injuries" and "earthquakes," "plastic surgery," "reconstructive surgery," "limb salvage" and "earthquake." Papers published between December 1992 and December 2012 were included, with no initial language restriction. Limb injuries are the commonest injuries seen accounting for 60 % of all injuries, with fractures in more than 50 % of those admitted to hospital, with between 8 and 13 % of these fractures open. After the first few days and once the immediate lifesaving phase is over, the management of these musculoskeletal and soft-tissue injuries are the commonest procedures required. Due to the predominance of soft-tissue and musculoskeletal injuries, plastic surgeons as specialists in soft-tissue reconstruction should be mobilised in the early stages of a disaster response as part of a multidisciplinary team with a focus on limb salvage.

The earthquake disaster risk characteristic and the problem in the earthquake emergency rescue of mountainous southwestern Sichuan

NASA Astrophysics Data System (ADS)

Yuan, S.; Xin, C.; Ying, Z.

2016-12-01

In recent years, earthquake disaster occurred frequently in Chinese mainland, the secondary disaster which have been caused by it is more serious in mountainous region. Because of the influence of terrain and geological conditions, the difficulty of earthquake emergency rescue work greatly increased, rescue force is also urged. Yet, it has been studied less on earthquake emergency rescue in mountainous region, the research in existing equipment whether can meet the actual needs of local earthquake emergency rescue is poorly. This paper intends to discuss and solve these problems. Through the mountainous regions Ganzi and Liangshan states in Sichuan field research, we investigated the process of earthquake emergency response and the projects for rescue force after an earthquake, and we also collected and collated local rescue force based data. By consulting experts and statistical analyzing the basic data, there are mainly two problems: The first is about local rescue force, they are poorly equipped and lack in the knowledge of medical help or identify architectural structure. There are no countries to establish a sound financial investment protection mechanism. Also, rescue equipment's updates and maintenance; The second problem is in earthquake emergency rescue progress. In the complicated geologic structure of mountainous regions, traffic and communication may be interrupted by landslides and mud-rock flows after earthquake. The outside rescue force may not arrive in time, rescue equipment was transported by manpower. Because of unknown earthquake disaster information, the local rescue force was deployed unreasonable. From the above, the local government worker should analyze the characteristics of the earthquake disaster in mountainous regions, and research how to improve their earthquake emergency rescue ability. We think they can do that by strengthening and regulating the rescue force structure, enhancing the skills and knowledge, training rescue workers

Children and the San Fernando earthquake

USGS Publications Warehouse

Howard, S. J.

1980-01-01

Before dawn, on February 9, 1971, a magnitude 6.4 earthquake occurred in the San Fernando Valley of California. On the following day, theSan Fernando Valley Child Guidance Clinic, through radio and newspapers, offered mental health crises services to children frightened by the earthquake. Response to this invitation was immediate and almost overwhelming. During the first 2 weeks, the Clinic's staff counseled hundreds of children who were experiencing various degrees of anxiety. 

Continuous Record of Permeability inside the Wenchuan Earthquake Fault Zone

NASA Astrophysics Data System (ADS)

Xue, L.; Li, H.; Brodsky, E. E.; Wang, H.; Pei, J.

2012-12-01

Faults are complex hydrogeological structures which include a highly permeable damage zone with fracture-dominated permeability. Since fractures are generated by earthquakes, we would expect that in the aftermath of a large earthquake, the permeability would be transiently high in a fault zone. Over time, the permeability may recover due to a combination of chemical and mechanical processes. However, the in situ fault zone hydrological properties are difficult to measure and have never been directly constrained on a fault zone immediately after a large earthquake. In this work, we use water level response to solid Earth tides to constrain the hydraulic properties inside the Wenchuan Earthquake Fault Zone. The transmissivity and storage determine the phase and amplitude response of the water level to the tidal loading. By measuring phase and amplitude response, we can constrain the average hydraulic properties of the damage zone at 800-1200 m below the surface (˜200-600 m from the principal slip zone). We use Markov chain Monte Carlo methods to evaluate the phase and amplitude responses and the corresponding errors for the largest semidiurnal Earth tide M2 in the time domain. The average phase lag is ˜30°, and the average amplitude response is 6×10-7 strain/m. Assuming an isotropic, homogenous and laterally extensive aquifer, the average storage coefficient S is 2×10-4 and the average transmissivity T is 6×10-7 m2 using the measured phase and the amplitude response. Calculation for the hydraulic diffusivity D with D=T/S, yields the reported value of D is 3×10-3 m2/s, which is two orders of magnitude larger than pump test values on the Chelungpu Fault which is the site of the Mw 7.6 Chi-Chi earthquake. If the value is representative of the fault zone, then this means the hydrology processes should have an effect on the earthquake rupture process. This measurement is done through continuous monitoring and we could track the evolution for hydraulic properties

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

PubMed Central

Burro, Roberto; Hall, Rob

2017-01-01

A major earthquake has a potentially highly traumatic impact on children’s psychological functioning. However, while many studies on children describe negative consequences in terms of mental health and psychiatric disorders, little is known regarding how the developmental processes of emotions can be affected following exposure to disasters. Objectives We explored whether and how the exposure to a natural disaster such as the 2012 Emilia Romagna earthquake affected the development of children’s emotional competence in terms of understanding, regulating, and expressing emotions, after two years, when compared with a control group not exposed to the earthquake. We also examined the role of class level and gender. Method The sample included two groups of children (n = 127) attending primary school: The experimental group (n = 65) experienced the 2012 Emilia Romagna earthquake, while the control group (n = 62) did not. The data collection took place two years after the earthquake, when children were seven or ten-year-olds. Beyond assessing the children’s understanding of emotions and regulating abilities with standardized instruments, we employed semi-structured interviews to explore their knowledge of earthquakes and associated emotions, and a structured task on the intensity of some target emotions. Results We applied Generalized Linear Mixed Models. Exposure to the earthquake did not influence the understanding and regulation of emotions. The understanding of emotions varied according to class level and gender. Knowledge of earthquakes, emotional language, and emotions associated with earthquakes were, respectively, more complex, frequent, and intense for children who had experienced the earthquake, and at increasing ages. Conclusions Our data extend the generalizability of theoretical models on children’s psychological functioning following disasters, such as the dose-response model and the organizational-developmental model for child resilience, and

Stochastic finite-fault simulation of ground motion from the August 11, 2012, M w 6.4 Ahar earthquake, northwestern Iran

NASA Astrophysics Data System (ADS)

Heidari, Reza

2016-04-01

In this study, the 11 August 2012 M w 6.4 Ahar earthquake is investigated using the ground motion simulation based on the stochastic finite-fault model. The earthquake occurred in northwestern Iran and causing extensive damage in the city of Ahar and surrounding areas. A network consisting of 58 acceleration stations recorded the earthquake within 8-217 km of the epicenter. Strong ground motion records from six significant well-recorded stations close to the epicenter have been simulated. These stations are installed in areas which experienced significant structural damage and humanity loss during the earthquake. The simulation is carried out using the dynamic corner frequency model of rupture propagation by extended fault simulation program (EXSIM). For this purpose, the propagation features of shear-wave including {Q}_s value, kappa value {k}_0 , and soil amplification coefficients at each site are required. The kappa values are obtained from the slope of smoothed amplitude of Fourier spectra of acceleration at higher frequencies. The determined kappa values for vertical and horizontal components are 0.02 and 0.05 s, respectively. Furthermore, an anelastic attenuation parameter is derived from energy decay of a seismic wave by using continuous wavelet transform (CWT) for each station. The average frequency-dependent relation estimated for the region is Q=(122± 38){f}^{(1.40± 0.16)}. Moreover, the horizontal to vertical spectral ratio H/V is applied to estimate the site effects at stations. Spectral analysis of the data indicates that the best match between the observed and simulated spectra occurs for an average stress drop of 70 bars. Finally, the simulated and observed results are compared with pseudo acceleration spectra and peak ground motions. The comparison of time series spectra shows good agreement between the observed and the simulated waveforms at frequencies of engineering interest.

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

NASA Astrophysics Data System (ADS)

Lin, K.; Wald, D. J.

2007-12-01

ShakeCast is a freely available, post-earthquake situational awareness application that automatically retrieves earthquake shaking data from ShakeMap, compares intensity measures against users" facilities, sends notifications of potential damage to responsible parties, and generates facility damage maps and other Web-based products for emergency managers and responders. ShakeMap, a tool used to portray the extent of potentially damaging shaking following an earthquake, provides overall information regarding the affected areas. When a potentially damaging earthquake occurs, utility and other lifeline managers, emergency responders, and other critical users have an urgent need for information about the impact on their particular facilities so they can make appropriate decisions and take quick actions to ensure safety and restore system functionality. To this end, ShakeCast estimates the potential damage to a user's widely distributed facilities by comparing the complex shaking distribution with the potentially highly variable damageability of their inventory to provide a simple, hierarchical list and maps showing structures or facilities most likely impacted. All ShakeMap and ShakeCast files and products are non-propriety to simplify interfacing with existing users" response tools and to encourage user-made enhancement to the software. ShakeCast uses standard RSS and HTTP requests to communicate with the USGS Web servers that host ShakeMaps, which are widely-distributed and heavily mirrored. The RSS approach allows ShakeCast users to initiate and receive selected ShakeMap products and information on software updates. To assess facility damage estimates, ShakeCast users can combine measured or estimated ground motion parameters with damage relationships that can be pre-computed, use one of these ground motion parameters as input, and produce a multi-state discrete output of damage likelihood. Presently three common approaches are being used to provide users with an

An empirical model for global earthquake fatality estimation

USGS Publications Warehouse

Jaiswal, Kishor; Wald, David

2010-01-01

We analyzed mortality rates of earthquakes worldwide and developed a country/region-specific empirical model for earthquake fatality estimation within the U.S. Geological Survey's Prompt Assessment of Global Earthquakes for Response (PAGER) system. The earthquake fatality rate is defined as total killed divided by total population exposed at specific shaking intensity level. The total fatalities for a given earthquake are estimated by multiplying the number of people exposed at each shaking intensity level by the fatality rates for that level and then summing them at all relevant shaking intensities. The fatality rate is expressed in terms of a two-parameter lognormal cumulative distribution function of shaking intensity. The parameters are obtained for each country or a region by minimizing the residual error in hindcasting the total shaking-related deaths from earthquakes recorded between 1973 and 2007. A new global regionalization scheme is used to combine the fatality data across different countries with similar vulnerability traits.

Network Structure and Community Evolution on Twitter: Human Behavior Change in Response to the 2011 Japanese Earthquake and Tsunami

PubMed Central

Lu, Xin; Brelsford, Christa

2014-01-01

To investigate the dynamics of social networks and the formation and evolution of online communities in response to extreme events, we collected three datasets from Twitter shortly before and after the 2011 earthquake and tsunami in Japan. We find that while almost all users increased their online activity after the earthquake, Japanese speakers, who are assumed to be more directly affected by the event, expanded the network of people they interact with to a much higher degree than English speakers or the global average. By investigating the evolution of communities, we find that the behavior of joining or quitting a community is far from random: users tend to stay in their current status and are less likely to join new communities from solitary or shift to other communities from their current community. While non-Japanese speakers did not change their conversation topics significantly after the earthquake, nearly all Japanese users changed their conversations to earthquake-related content. This study builds a systematic framework for investigating human behaviors under extreme events with online social network data and our findings on the dynamics of networks and communities may provide useful insight for understanding how patterns of social interaction are influenced by extreme events. PMID:25346468

Network Structure and Community Evolution on Twitter: Human Behavior Change in Response to the 2011 Japanese Earthquake and Tsunami

NASA Astrophysics Data System (ADS)

Lu, Xin; Brelsford, Christa

2014-10-01

To investigate the dynamics of social networks and the formation and evolution of online communities in response to extreme events, we collected three datasets from Twitter shortly before and after the 2011 earthquake and tsunami in Japan. We find that while almost all users increased their online activity after the earthquake, Japanese speakers, who are assumed to be more directly affected by the event, expanded the network of people they interact with to a much higher degree than English speakers or the global average. By investigating the evolution of communities, we find that the behavior of joining or quitting a community is far from random: users tend to stay in their current status and are less likely to join new communities from solitary or shift to other communities from their current community. While non-Japanese speakers did not change their conversation topics significantly after the earthquake, nearly all Japanese users changed their conversations to earthquake-related content. This study builds a systematic framework for investigating human behaviors under extreme events with online social network data and our findings on the dynamics of networks and communities may provide useful insight for understanding how patterns of social interaction are influenced by extreme events.

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

PubMed

Sepúlveda, Roger D; Valdivia, Nelson

2016-01-01

. Therefore, our results suggest that the effects of the Maule mega-earthquake on the ecological communities were spatially heterogeneous and highly localised. We suggest that high mobility and other species' adaptations to the dynamic environmental conditions of sandy beaches might explain the comparatively high resilience of these assemblages. With this work we hope to motivate further experimental research on the role of individual- and population-level properties in the response of sandy-beach communities to interacting sources of disturbances.

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

PubMed Central

Sepúlveda, Roger D.; Valdivia, Nelson

2016-01-01

tsunami. Therefore, our results suggest that the effects of the Maule mega-earthquake on the ecological communities were spatially heterogeneous and highly localised. We suggest that high mobility and other species’ adaptations to the dynamic environmental conditions of sandy beaches might explain the comparatively high resilience of these assemblages. With this work we hope to motivate further experimental research on the role of individual- and population-level properties in the response of sandy-beach communities to interacting sources of disturbances. PMID:27383744

Using SW4 for 3D Simulations of Earthquake Strong Ground Motions: Application to Near-Field Strong Motion, Building Response, Basin Edge Generated Waves and Earthquakes in the San Francisco Bay Are

NASA Astrophysics Data System (ADS)

Rodgers, A. J.; Pitarka, A.; Petersson, N. A.; Sjogreen, B.; McCallen, D.; Miah, M.

2016-12-01

Simulation of earthquake ground motions is becoming more widely used due to improvements of numerical methods, development of ever more efficient computer programs (codes), and growth in and access to High-Performance Computing (HPC). We report on how SW4 can be used for accurate and efficient simulations of earthquake strong motions. SW4 is an anelastic finite difference code based on a fourth order summation-by-parts displacement formulation. It is parallelized and can run on one or many processors. SW4 has many desirable features for seismic strong motion simulation: incorporation of surface topography; automatic mesh generation; mesh refinement; attenuation and supergrid boundary conditions. It also has several ways to introduce 3D models and sources (including Standard Rupture Format for extended sources). We are using SW4 to simulate strong ground motions for several applications. We are performing parametric studies of near-fault motions from moderate earthquakes to investigate basin edge generated waves and large earthquakes to provide motions to engineers study building response. We show that 3D propagation near basin edges can generate significant amplifications relative to 1D analysis. SW4 is also being used to model earthquakes in the San Francisco Bay Area. This includes modeling moderate (M3.5-5) events to evaluate the United States Geologic Survey's 3D model of regional structure as well as strong motions from the 2014 South Napa earthquake and possible large scenario events. Recently SW4 was built on a Commodity Technology Systems-1 (CTS-1) at LLNL, new systems for capacity computing at the DOE National Labs. We find SW4 scales well and runs faster on these systems compared to the previous generation of LINUX clusters.

Exciton Absorption Spectra by Linear Response Methods:Application to Conjugated Polymers

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

Mosquera, Martin A.; Jackson, Nicholas E.; Fauvell, Thomas J.

The theoretical description of the timeevolution of excitons requires, as an initial step, the calculation of their spectra, which has been inaccessible to most users due to the high computational scaling of conventional algorithms and accuracy issues caused by common density functionals. Previously (J. Chem. Phys. 2016, 144, 204105), we developed a simple method that resolves these issues. Our scheme is based on a two-step calculation in which a linear-response TDDFT calculation is used to generate orbitals perturbed by the excitonic state, and then a second linear-response TDDFT calculation is used to determine the spectrum of excitations relative to themore » excitonic state. Herein, we apply this theory to study near-infrared absorption spectra of excitons in oligomers of the ubiquitous conjugated polymers poly(3-hexylthiophene) (P3HT), poly(2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene) (MEH-PPV), and poly(benzodithiophene-thieno[3,4-b]thiophene) (PTB7). For P3HT and MEH-PPV oligomers, the calculated intense absorption bands converge at the longest wavelengths for 10 monomer units, and show strong consistency with experimental measurements. The calculations confirm that the exciton spectral features in MEH-PPV overlap with those of the bipolaron formation. In addition, our calculations identify the exciton absorption bands in transient absorption spectra measured by our group for oligomers (1, 2, and 3 units) of PTB7. For all of the cases studied, we report the dominant orbital excitations contributing to the optically active excited state-excited state transitions, and suggest a simple rule to identify absorption peaks at the longest wavelengths. We suggest our methodology could be considered for further evelopments in theoretical transient spectroscopy to include nonadiabatic effects, coherences, and to describe the formation of species such as charge-transfer states and polaron pairs.« less

Poroelastic Response to the 2012 Costa Rica Earthquake and the Effects on Geodetic Surface Deformation and Groundwater Fluxes

NASA Astrophysics Data System (ADS)

McCormack, K. A.; Hesse, M.

2016-12-01

Remote sensing and geodetic measurements are providing a new wealth of spatially distributed, time-series data that have the ability to improve our understanding of co-seismic rupture and post-seismic processes in subduction zones. Following a large earthquake, large-scale deformation is influenced by a myriad of post-seismic processes occurring on different spatial and temporal scales. These include continued slip on the fault plane (after-slip), a poroelastic response due to the movement of over-pressurized groundwater and viscoelastic relaxation of the underlying mantle. Often, the only means of observing these phenomena are through surface deformation measurements - either GPS or InSAR. Such tools measure the combined result of all these processes, which makes studying the effects of any single process difficult. For the 2012 Mw 7.6 Costa Rica Earthquake, we formulate a Bayesian inverse problem to infer the slip distribution on the plate interface using an elastic finite element model and GPS surface deformation measurements. From this study we identify a horseshoe-shaped rupture area surrounding a locked patch that is likely to release stress in the future. The results of our inversion are then used as an initial condition in a coupled poroelastic forward model to investigate the role of poroelastic effects on post-seismic deformation and stress transfer. We model the co-seismic pore pressure change as well as the pressure evolution and resulting deformation in the months after the earthquake. The surface permeability field is constrained by pump-test data from 526 groundwater wells throughout the study area. The results of the forward model indicate that earthquake-induced pore pressure changes dissipate quickly in most areas near the surface, resulting in relaxation of the surface in the seven to twenty days following the earthquake. Near the subducting slab interface, pore pressure changes can be an order of magnitude larger and may persist for many months

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.

Analysis of the international and US response to the Haiti earthquake: recommendations for change.

PubMed

Kirsch, Thomas; Sauer, Lauren; Guha Sapir, Debarati

2012-10-01

The 2010 earthquake in Haiti was unprecedented in its impact. The dual loss of the Haitian government and United Nations (UN) leadership led to an atypical disaster response driven by the US government and military. Although the response was massive, the leadership and logistical support were initially insufficient, and the UN cluster system struggled with the overwhelming influx of nontraditional agencies and individuals, which complicated the health care response. Moreover, the provision of care was beyond the country's health care standards. The management of the US government resembled a whole-of-government domestic response, combined with a massive military presence that went beyond logistical support. Among the most important lessons learned were the management of the response and how it could be strengthened by adapting a structure such as the domestic National Response Framework. Also, mechanisms were needed to increase the limited personnel to surge in a major response. One obvious pool has been the military, but the military needs to increase integration with the humanitarian community and improve its own humanitarian response expertise. In addition, information management needs standardized tools and analysis to improve its use of independent agencies.

Shallow seismic source parameter determination using intermediate-period surface wave amplitude spectra

NASA Astrophysics Data System (ADS)

Fox, Benjamin D.; Selby, Neil D.; Heyburn, Ross; Woodhouse, John H.

2012-09-01

Estimating reliable depths for shallow seismic sources is important in both seismo-tectonic studies and in seismic discrimination studies. Surface wave excitation is sensitive to source depth, especially at intermediate and short-periods, owing to the approximate exponential decay of surface wave displacements with depth. A new method is presented here to retrieve earthquake source parameters from regional and teleseismic intermediate period (100-15 s) fundamental-mode surface wave recordings. This method makes use of advances in mapping global dispersion to allow higher frequency surface wave recordings at regional and teleseismic distances to be used with more confidence than in previous studies and hence improve the resolution of depth estimates. Synthetic amplitude spectra are generated using surface wave theory combined with a great circle path approximation, and a grid of double-couple sources are compared with the data. Source parameters producing the best-fitting amplitude spectra are identified by minimizing the least-squares misfit in logarithmic amplitude space. The F-test is used to search the solution space for statistically acceptable parameters and the ranges of these variables are used to place constraints on the best-fitting source. Estimates of focal mechanism, depth and scalar seismic moment are determined for 20 small to moderate sized (4.3 ≤Mw≤ 6.4) earthquakes. These earthquakes are situated across a wide range of geographic and tectonic locations and describe a range of faulting styles over the depth range 4-29 km. For the larger earthquakes, comparisons with other studies are favourable, however existing source determination procedures, such as the CMT technique, cannot be performed for the smaller events. By reducing the magnitude threshold at which robust source parameters can be determined, the accuracy, especially at shallow depths, of seismo-tectonic studies, seismic hazard assessments, and seismic discrimination investigations can

SSI-bridge : soil bridge interaction during long-duration earthquake motions.

DOT National Transportation Integrated Search

2014-09-01

The seismic response of a complete soil-bridge system during shallow, crustal and subduction zone earthquakes is the topic of this report. Specifically, the effects of earthquake duration on the seismic performance of soil-bridge systems are examined...

Why earthquakes correlate weakly with the solid Earth tides: Effects of periodic stress on the rate and probability of earthquake occurrence

USGS Publications Warehouse

Beeler, N.M.; Lockner, D.A.

2003-01-01

We provide an explanation why earthquake occurrence does not correlate well with the daily solid Earth tides. The explanation is derived from analysis of laboratory experiments in which faults are loaded to quasiperiodic failure by the combined action of a constant stressing rate, intended to simulate tectonic loading, and a small sinusoidal stress, analogous to the Earth tides. Event populations whose failure times correlate with the oscillating stress show two modes of response; the response mode depends on the stressing frequency. Correlation that is consistent with stress threshold failure models, e.g., Coulomb failure, results when the period of stress oscillation exceeds a characteristic time tn; the degree of correlation between failure time and the phase of the driving stress depends on the amplitude and frequency of the stress oscillation and on the stressing rate. When the period of the oscillating stress is less than tn, the correlation is not consistent with threshold failure models, and much higher stress amplitudes are required to induce detectable correlation with the oscillating stress. The physical interpretation of tn is the duration of failure nucleation. Behavior at the higher frequencies is consistent with a second-order dependence of the fault strength on sliding rate which determines the duration of nucleation and damps the response to stress change at frequencies greater than 1/tn. Simple extrapolation of these results to the Earth suggests a very weak correlation of earthquakes with the daily Earth tides, one that would require >13,000 earthquakes to detect. On the basis of our experiments and analysis, the absence of definitive daily triggering of earthquakes by the Earth tides requires that for earthquakes, tn exceeds the daily tidal period. The experiments suggest that the minimum typical duration of earthquake nucleation on the San Andreas fault system is ???1 year.

Laboratory-based maximum slip rates in earthquake rupture zones and radiated energy

USGS Publications Warehouse

McGarr, A.; Fletcher, Joe B.; Boettcher, M.; Beeler, N.; Boatwright, J.

2010-01-01

Laboratory stick-slip friction experiments indicate that peak slip rates increase with the stresses loading the fault to cause rupture. If this applies also to earthquake fault zones, then the analysis of rupture processes is simplified inasmuch as the slip rates depend only on the local yield stress and are independent of factors specific to a particular event, including the distribution of slip in space and time. We test this hypothesis by first using it to develop an expression for radiated energy that depends primarily on the seismic moment and the maximum slip rate. From laboratory results, the maximum slip rate for any crustal earthquake, as well as various stress parameters including the yield stress, can be determined based on its seismic moment and the maximum slip within its rupture zone. After finding that our new equation for radiated energy works well for laboratory stick-slip friction experiments, we used it to estimate radiated energies for five earthquakes with magnitudes near 2 that were induced in a deep gold mine, an M 2.1 repeating earthquake near the San Andreas Fault Observatory at Depth (SAFOD) site and seven major earthquakes in California and found good agreement with energies estimated independently from spectra of local and regional ground-motion data. Estimates of yield stress for the earthquakes in our study range from 12 MPa to 122 MPa with a median of 64 MPa. The lowest value was estimated for the 2004 M 6 Parkfield, California, earthquake whereas the nearby M 2.1 repeating earthquake, as recorded in the SAFOD pilot hole, showed a more typical yield stress of 64 MPa.

Comparative Analysis of Emergency Response Operations: Haiti Earthquake in January 2010 and Pakistan’s Flood in 2010

DTIC Science & Technology

2011-09-01

Earthquake, Pakistan, Flood, Emergency Response Operations, International Community, HA/DR, United Nations , FRC, NDMA , ICT 16. PRICE CODE 17. SECURITY...Registration Authority NATO North Atlantic Treaty Organization NDMA National Disaster and Management Authority NDMC National Disaster Management...complicates relief efforts. 6 NDMA Pakistan, “Pakistan Floods-Summary of Damages,” No Author. Accessed 24

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.

Continuous borehole strain and pore pressure in the near field of the 28 September 2004 M 6.0 parkfield, California, earthquake: Implications for nucleation, fault response, earthquake prediction and tremor

USGS Publications Warehouse

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

2006-01-01

Near-field observations of high-precision borehole strain and pore pressure, show no indication of coherent accelerating strain or pore pressure during the weeks to seconds before the 28 September 2004 M 6.0 Parkfield earthquake. Minor changes in strain rate did occur at a few sites during the last 24 hr before the earthquake but these changes are neither significant nor have the form expected for strain during slip coalescence initiating fault failure. Seconds before the event, strain is stable at the 10-11 level. Final prerupture nucleation slip in the hypocentral region is constrained to have a moment less than 2 ?? 1012 N m (M 2.2) and a source size less than 30 m. Ground displacement data indicate similar constraints. Localized rupture nucleation and runaway precludes useful prediction of damaging earthquakes. Coseismic dynamic strains of about 10 microstrain peak-to-peak were superimposed on volumetric strain offsets of about 0.5 microstrain to the northwest of the epicenter and about 0.2 microstrain to the southeast of the epicenter, consistent with right lateral slip. Observed strain and Global Positioning System (GPS) offsets can be simply fit with 20 cm of slip between 4 and 10 km on a 20-km segment of the fault north of Gold Hill (M0 = 7 ?? 1017 N m). Variable slip inversion models using GPS data and seismic data indicate similar moments. Observed postseismic strain is 60% to 300% of the coseismic strain, indicating incomplete release of accumulated strain. No measurable change in fault zone compliance preceding or following the earthquake is indicated by stable earth tidal response. No indications of strain change accompany nonvolcanic tremor events reported prior to and following the earthquake.

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

With more than 25 million people at risk from high hazard faults in California alone, Earthquake Early Warning (EEW) presents a promising public safety and emergency response tool. EEW represents the real-time end of an earthquake information spectrum which also includes near real-time notifications of earthquake location, magnitude, and shaking levels; as well as geographic information system (GIS)-based products for compiling and visually displaying processed earthquake data such as ShakeMap and ShakeCast. Improvements to and increased multi-national implementation of EEW have stimulated interest in how such information products could be used in the future. Lifeline organizations, consisting of utilities and transportation systems, can use both onsite and regional EEW information as part of their risk management and public safety programs. Regional EEW information can provide improved situational awareness to system operators before automatic system protection devices activate, and allow trained personnel to take precautionary measures. On-site EEW is used for earthquake-actuated automatic gas shutoff valves, triggered garage door openers at fire stations, system controls, etc. While there is no public policy framework for preemptive, precautionary electricity or gas service shutdowns by utilities in the United States, gas shut-off devices are being required at the building owner level by some local governments. In the transportation sector, high-speed rail systems have already demonstrated the ‘proof of concept’ for EEW in several countries, and more EEW systems are being installed. Recently the Bay Area Rapid Transit District (BART) began collaborating with the California Integrated Seismic Network (CISN) and others to assess the potential benefits of EEW technology to mass transit operations and emergency response in the San Francisco Bay region. A key issue in this assessment is that significant earthquakes are likely to occur close to or within the BART

Preparing for an Earthquake: Information for Schools and Families

ERIC Educational Resources Information Center

Heath, Melissa Allen; Dean, Brenda

2008-01-01

Over the past decade, catastrophic earthquakes have garnered international attention regarding the need for improving immediate and ongoing support services for disrupted communities. Following the December 26, 2004 Indonesian earthquake, the Indian Ocean tsunami was responsible for displacing millions and taking the lives of an estimated 320,000…

Web-Based Real Time Earthquake Forecasting and Personal Risk Management

NASA Astrophysics Data System (ADS)

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

2012-12-01

Earthquake forecasts have been computed by a variety of countries and economies world-wide for over two decades. For the most part, forecasts have been computed for insurance, reinsurance and underwriters of catastrophe bonds. One example is the Working Group on California Earthquake Probabilities that has been responsible for the official California earthquake forecast since 1988. However, in a time of increasingly severe global financial constraints, we are now moving inexorably towards personal risk management, wherein mitigating risk is becoming the responsibility of individual members of the public. Under these circumstances, open access to a variety of web-based tools, utilities and information is a necessity. Here we describe a web-based system that has been operational since 2009 at www.openhazards.com and www.quakesim.org. Models for earthquake physics and forecasting require input data, along with model parameters. The models we consider are the Natural Time Weibull (NTW) model for regional earthquake forecasting, together with models for activation and quiescence. These models use small earthquakes ('seismicity-based models") to forecast the occurrence of large earthquakes, either through varying rates of small earthquake activity, or via an accumulation of this activity over time. These approaches use data-mining algorithms combined with the ANSS earthquake catalog. The basic idea is to compute large earthquake probabilities using the number of small earthquakes that have occurred in a region since the last large earthquake. Each of these approaches has computational challenges associated with computing forecast information in real time. Using 25 years of data from the ANSS California-Nevada catalog of earthquakes, we show that real-time forecasting is possible at a grid scale of 0.1o. We have analyzed the performance of these models using Reliability/Attributes and standard Receiver Operating Characteristic (ROC) tests. We show how the Reliability and

New Satellite Damage Maps Assist Italy Earthquake Disaster Response

NASA Image and Video Library

2016-09-01

Italy earthquake. The quake has caused significant damage in the historic town of Amatrice. To assist in the disaster response efforts, scientists at NASA's Jet Propulsion Laboratory, Pasadena, California, and the California Institute of Technology in Pasadena, in collaboration with the Italian Space Agency (ASI), generated this image of the earthquake's hardest-hit region. The 40-by-75 mile (65-by-120 kilometer) Damage Proxy Map (DPM) was derived from two consecutive frames of the Japan Aerospace Exploration Agency's (JAXA's) L-band interferometric synthetic aperture radar (InSAR) data from the ALOS-2 satellite (cyan rectangles), and the 25-by-31 mile (40-by-50 kilometer) DPM was derived from InSAR data from the Agenzia Spaciale Italiana's (ASI's) X-band COSMO-SkyMed satellite (red rectangle). Both DPMs cover the historic town of Amatrice, revealing severe damage in the western side of the town (right panels). The time span of the data for the change is Jan. 27, 2016 to Aug. 24, 2016 for ALOS-2 and Aug. 20, 2016 to Aug. 28, 2016 for COSMO-SkyMed. Each pixel in the damage proxy map is about 100 feet (30 meters) across. The SAR data were processed by the Advanced Rapid Imaging and Analysis (ARIA) team at JPL and Caltech. The technique uses a prototype algorithm to rapidly detect surface changes caused by natural or human-produced damage. The assessment technique is most sensitive to destruction of the built environment. When the radar images areas with little to no destruction, its image pixels are transparent. Increased opacity of the radar image pixels reflects damage, with areas in red reflecting the heaviest damage to cities and towns. The color variations from yellow to red indicate increasingly more significant ground surface change. Preliminary validation was done by comparing the DPMs to a damage assessment map produced by the Copernicus Emergency Management Service, which is based on visual inspection of before and after high-resolution aerial imagery

Coseismic water level changes induced by two distant earthquakes in multiple wells of the Chinese mainland

NASA Astrophysics Data System (ADS)

Ma, Yuchuan; Huang, Fuqiong

2017-01-01

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

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

USGS Publications Warehouse

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

2003-01-01

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

Earthquake Early Warning: User Education and Designing Effective Messages

NASA Astrophysics Data System (ADS)

Burkett, E. R.; Sellnow, D. D.; Jones, L.; Sellnow, T. L.

2014-12-01

The U.S. Geological Survey (USGS) and partners are transitioning from test-user trials of a demonstration earthquake early warning system (ShakeAlert) to deciding and preparing how to implement the release of earthquake early warning information, alert messages, and products to the public and other stakeholders. An earthquake early warning system uses seismic station networks to rapidly gather information about an occurring earthquake and send notifications to user devices ahead of the arrival of potentially damaging ground shaking at their locations. Earthquake early warning alerts can thereby allow time for actions to protect lives and property before arrival of damaging shaking, if users are properly educated on how to use and react to such notifications. A collaboration team of risk communications researchers and earth scientists is researching the effectiveness of a chosen subset of potential earthquake early warning interface designs and messages, which could be displayed on a device such as a smartphone. Preliminary results indicate, for instance, that users prefer alerts that include 1) a map to relate their location to the earthquake and 2) instructions for what to do in response to the expected level of shaking. A number of important factors must be considered to design a message that will promote appropriate self-protective behavior. While users prefer to see a map, how much information can be processed in limited time? Are graphical representations of wavefronts helpful or confusing? The most important factor to promote a helpful response is the predicted earthquake intensity, or how strong the expected shaking will be at the user's location. Unlike Japanese users of early warning, few Californians are familiar with the earthquake intensity scale, so we are exploring how differentiating instructions between intensity levels (e.g., "Be aware" for lower shaking levels and "Drop, cover, hold on" at high levels) can be paired with self-directed supplemental

Modelling of Earthquake Ground Response in the Maltese Islands Using Results from Geophysical Investigations

NASA Astrophysics Data System (ADS)

Farrugia, D.; Galea, P. M.; D'Amico, S.

2016-12-01

The Maltese archipelago is characterised by a four layer sequence of limestones and clays. The Lower Coralline Limestone is the oldest exposed layer, overlain by the Globigerina Limestone. Some parts of the islands are characterised by Upper Coralline Limestone plateaus and hillcaps covering a soft Blue Clay layer which can be up to 75 m thick. The BC layer introduces a velocity inversion in the stratigraphy, and makes the Vs30 parameter not always suitable for seismic microzonation purposes. Such a layer may still produce amplification effects, however would not contribute to the numerical mean of Vs in the upper 30m. In this study, site response analysis for the Maltese islands is conducted, with particular attention being given to sites described above. Array and single-station measurements of ambient noise were first carried out at numerous sites in Malta. Surface wave dispersion and H/V curves were jointly inverted using a genetic algorithm, so that the Vs profiles were obtained. The stochastic extended-fault algorithm EXSIM was used to simulate historical and recent earthquakes at the bedrock. These were used in conjunction with the equivalent-linear programme SHAKE2000 to carry out the site-specific response analysis, using the derived geophysical models. Maps of ground motion parameters, such as peak ground acceleration and spectral accelerations, confirm that the clay, even when buried under a hard outcropping layer can still produce significant amplifications at frequencies which are of engineering interest when considering the recent urbanisation patterns. The results of this project will give important, and previously unavailable information and predictions about the behaviour of local lithotypes in response to earthquake ground shaking while also contributing knowledge about the issue of buried low velocity layers.

Do weak global stresses synchronize earthquakes?

NASA Astrophysics Data System (ADS)

Bendick, R.; Bilham, R.

2017-08-01

Insofar as slip in an earthquake is related to the strain accumulated near a fault since a previous earthquake, and this process repeats many times, the earthquake cycle approximates an autonomous oscillator. Its asymmetric slow accumulation of strain and rapid release is quite unlike the harmonic motion of a pendulum and need not be time predictable, but still resembles a class of repeating systems known as integrate-and-fire oscillators, whose behavior has been shown to demonstrate a remarkable ability to synchronize to either external or self-organized forcing. Given sufficient time and even very weak physical coupling, the phases of sets of such oscillators, with similar though not necessarily identical period, approach each other. Topological and time series analyses presented here demonstrate that earthquakes worldwide show evidence of such synchronization. Though numerous studies demonstrate that the composite temporal distribution of major earthquakes in the instrumental record is indistinguishable from random, the additional consideration of event renewal interval serves to identify earthquake groupings suggestive of synchronization that are absent in synthetic catalogs. We envisage the weak forces responsible for clustering originate from lithospheric strain induced by seismicity itself, by finite strains over teleseismic distances, or by other sources of lithospheric loading such as Earth's variable rotation. For example, quasi-periodic maxima in rotational deceleration are accompanied by increased global seismicity at multidecadal intervals.

The effect of nonlocal dielectric response on the surface-enhanced Raman and fluorescence spectra of molecular systems

NASA Astrophysics Data System (ADS)

Wei, Yong; Pei, Huan; Li, Li; Zhu, Yanying

2018-06-01

We present a theoretical study on the influence of the nonlocal dielectric response on surface-enhanced resonant Raman scattering (SERRS) and fluorescence (SEF) spectra of a model molecule confined in the center of a Ag nanoparticle (NP) dimer. In the simulations, the nonlocal dielectric response caused by the electron–hole pair generation in Ag NPs was computed with the d-parameter theory, and the scattering spectra of a model molecule representing the commonly used fluorescent dye rhodamine 6G (R6G) were obtained by density-matrix calculations. The influence of the separation between Ag NP dimers on the damping rate and scattering spectra with and without the nonlocal response were systematically analyzed. The results show that the nonlocal dielectric response is very sensitive to the gap distance of the NP dimers, and it undergoes much faster decay with the increase of the separation than the radiative and energy transfer rates. The Raman and fluorescence peaks as simulated with the nonlocal dielectric response are relative weaker than that without the nonlocal effect for smaller NP separations because the extra decay rates of the nonlocal effect could reduce both the population of the excited state and the interband coherence between the ground and excited states. Our result also indicates that the nonlocal effect is more prominent on the SEF process than the SERRS process.

The effect of nonlocal dielectric response on the surface-enhanced Raman and fluorescence spectra of molecular systems.

PubMed

Wei, Yong; Pei, Huan; Li, Li; Zhu, Yanying

2018-05-04

We present a theoretical study on the influence of the nonlocal dielectric response on surface-enhanced resonant Raman scattering (SERRS) and fluorescence (SEF) spectra of a model molecule confined in the center of a Ag nanoparticle (NP) dimer. In the simulations, the nonlocal dielectric response caused by the electron-hole pair generation in Ag NPs was computed with the d-parameter theory, and the scattering spectra of a model molecule representing the commonly used fluorescent dye rhodamine 6G (R6G) were obtained by density-matrix calculations. The influence of the separation between Ag NP dimers on the damping rate and scattering spectra with and without the nonlocal response were systematically analyzed. The results show that the nonlocal dielectric response is very sensitive to the gap distance of the NP dimers, and it undergoes much faster decay with the increase of the separation than the radiative and energy transfer rates. The Raman and fluorescence peaks as simulated with the nonlocal dielectric response are relative weaker than that without the nonlocal effect for smaller NP separations because the extra decay rates of the nonlocal effect could reduce both the population of the excited state and the interband coherence between the ground and excited states. Our result also indicates that the nonlocal effect is more prominent on the SEF process than the SERRS process.

"Breaking Ground" in the Use of Social Media: A Case Study of a University Earthquake Response to Inform Educational Design with Facebook

ERIC Educational Resources Information Center

Dabner, Nicki

2012-01-01

On September 4 2010, a massive 7.1 magnitude earthquake struck the Canterbury region in the South Island of New Zealand. The response from the University of Canterbury was immediate and carefully co-ordinated, with the university's web-based environment and a responsive site developed on the social media platform "Facebook" becoming…

Chile Earthquake: U.S. and International Response

DTIC Science & Technology

2010-03-11

5 United Nations Office for the Coordination of Humanitarian Affairs, “Chile Earthquake: Situation Report #2,” March 1, 2010; Gobierno de Chile...U.S. Department of State, March 2, 2010. 6 “Bachelet decreta primer Estado de Catástrofe desde terremoto de 1985,” El Mercurio (Chile), March 1...2010; “Amplían toque de queda en zonas más afectadas por terremoto en Chile,” Agence France Presse, March 1, 2010; “160 detained, one killed during

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.

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

PubMed

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

2017-08-01

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

Disaster Response and Decision Support in Partnership with the California Earthquake Clearinghouse

NASA Astrophysics Data System (ADS)

Glasscoe, M. T.; Rosinski, A.; Vaughan, D.; Morentz, J.

2014-12-01

Getting the right information to the right people at the right time is critical during a natural disaster. E-DECIDER (Emergency Data Enhanced Cyber-Infrastructure for Disaster Evaluation and Response) is a NASA decision support system designed to produce remote sensing and geophysical modeling data products that are relevant to the emergency preparedness and response communities and serve as a gateway to enable the delivery of NASA decision support products to these communities. The E-DECIDER decision support system has several tools, services, and products that have been used to support end-user exercises in partnership with the California Earthquake Clearinghouse since 2012, including near real-time deformation modeling results and on-demand maps of critical infrastructure that may have been potentially exposed to damage by a disaster. E-DECIDER's underlying service architecture allows the system to facilitate delivery of NASA decision support products to the Clearinghouse through XchangeCore Web Service Data Orchestration that allows trusted information exchange among partner agencies. This in turn allows Clearinghouse partners to visualize data products produced by E-DECIDER and other NASA projects through incident command software such as SpotOnResponse or ArcGIS Online.

Strike-slip earthquakes can also be detected in the ionosphere

NASA Astrophysics Data System (ADS)

Astafyeva, Elvira; Rolland, Lucie M.; Sladen, Anthony

2014-11-01

It is generally assumed that co-seismic ionospheric disturbances are generated by large vertical static displacements of the ground during an earthquake. Consequently, it is expected that co-seismic ionospheric disturbances are only observable after earthquakes with a significant dip-slip component. Therefore, earthquakes dominated by strike-slip motion, i.e. with very little vertical co-seismic component, are not expected to generate ionospheric perturbations. In this work, we use total electron content (TEC) measurements from ground-based GNSS-receivers to study ionospheric response to six recent largest strike-slip earthquakes: the Mw7.8 Kunlun earthquake of 14 November 2001, the Mw8.1 Macquarie earthquake of 23 December 2004, the Sumatra earthquake doublet, Mw8.6 and Mw8.2, of 11 April 2012, the Mw7.7 Balochistan earthquake of 24 September 2013 and the Mw 7.7 Scotia Sea earthquake of 17 November 2013. We show that large strike-slip earthquakes generate large ionospheric perturbations of amplitude comparable with those induced by dip-slip earthquakes of equivalent magnitude. We consider that in the absence of significant vertical static co-seismic displacements of the ground, other seismological parameters (primarily the magnitude of co-seismic horizontal displacements, seismic fault dimensions, seismic slip) may contribute in generation of large-amplitude ionospheric perturbations.

Evaluation of Site Amplification Functions For Generalized Soil Types Using Earthquake Records and Spectral Models

NASA Astrophysics Data System (ADS)

Sokolov, V.; Loh, C. H.; Wen, K. L.

When evaluating the local site influence on seismic ground motion, in certain cases (e.g. building codes provisions) it is sufficient to describe the variety of soil condi- tions by a few number of generalized site classes. The site classification system that is widely used at present is based on on the properties of top 30 m of soil column, dis- regarding the characteristics of the deeper geology. Six site categories are defined on the basis of averaged shear waves velocity, namely: A - hard rock; B - rock; C - very dense or stiff soil; D - stiff soil; E - soft soil; F - soils requiring special studies. The generalized site amplification curves were developed for several site classes in west- ern US (Boore and Joyner, 1997) and Greece (Klimis et al., 1999) using available geotechnical data from near-surface boreholes. We propose to evaluate the amplifica- tion functions as the ratios between the spectra of real earthquakes recordings and the spectra modeled for "very hard rock" (VHR) conditions. The VHR spectra (regional source scaling and attenuation models) are constructed on the basis of ground motion records. The approach allows, on the one hand, to analyze all obtained records. On the other hand, it is possible to test applicability of the used spectral model. Moreover, the uncertainty of site response may be evaluated and described in terms of random variable characteristics to be considered in seismic hazard analysis. The results of the approach application are demonstrated for the case of Taiwan region. The char- acteristics of site amplification functions (mean values and standard deviation) were determined and analyzed in frequency range of 0.2-13 Hz for site classes B and C us- ing recordings of the 1999 Chi-Chi, Taiwan, earthquake (M=7.6), strong aftershocks (M=6.8), and several earthquakes (M < 6.5) occurred in the region in 1995-1998. When comparing the empirical amplification function resulting from the Taiwan data with that proposed for western US

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).

USGS remote sensing coordination for the 2010 Haiti earthquake

USGS Publications Warehouse

Duda, Kenneth A.; Jones, Brenda

2011-01-01

In response to the devastating 12 January 2010, earthquake in Haiti, the US Geological Survey (USGS) provided essential coordinating services for remote sensing activities. Communication was rapidly established between the widely distributed response teams and data providers to define imaging requirements and sensor tasking opportunities. Data acquired from a variety of sources were received and archived by the USGS, and these products were subsequently distributed using the Hazards Data Distribution System (HDDS) and other mechanisms. Within six weeks after the earthquake, over 600,000 files representing 54 terabytes of data were provided to the response community. The USGS directly supported a wide variety of groups in their use of these data to characterize post-earthquake conditions and to make comparisons with pre-event imagery. The rapid and continuing response achieved was enabled by existing imaging and ground systems, and skilled personnel adept in all aspects of satellite data acquisition, processing, distribution and analysis. The information derived from image interpretation assisted senior planners and on-site teams to direct assistance where it was most needed.

Groundwater storage inferred from earthquake activities around East Asia and West Pacific Ocean

NASA Astrophysics Data System (ADS)

Shih, David Ching-Fang

2017-01-01

Groundwater is a necessary and indispensable resource in the gradual depletion of the amount in the world. Groundwater storage is an important indicator to evaluate the capability of volume of water can be released from the aquifer. This research highlights a new assessment to infer the storage of aquifer using earthquakes activated around East Asia and the ring of fire at West Pacific Ocean. Ten significant seismic events are used to evaluate the groundwater storage at an observation station. By analyzing the spectra of groundwater level and seismogram, it is evident that the period varied in 7-25 s of Rayleigh waves significantly dominate propagation from the epicenter of earthquakes to the observation station. The storage coefficient is then shown in the order of 10-4-10-3. The major innovation of this study suggests that to concretely deduce the groundwater storage by earthquake activity has become feasible.

Disaster response under One Health in the aftermath of Nepal earthquake, 2015.

PubMed

Asokan, G V; Vanitha, A

2017-03-01

Until now, an estimate quotes that 1100 healthcare facilities were damaged and over 100,000 livestock lost in the two earthquakes that occurred in April and May of 2015 in Nepal. Threats of infectious diseases, mostly zoonoses, could affect Nepal's economy, trade, and tourism, and reaching the targets of the United Nations Millennium Development Goals. Historically, outbreaks of infectious diseases, including zoonoses, were largely associated with the aftereffects of the earthquakes. It has been documented that zoonoses constitute 61% of all known infectious diseases. Therefore, the purpose of this communication was to examine the infectious disease outbreaks after earthquakes around the world and explore the risk assessment of the zoonoses threats reported in Nepal and highlight adopting One Health. Our summaries on reported zoonoses in Nepal have shown that parasitic zoonoses were predominant, but other infectious disease outbreaks can occur. The fragile public health infrastructure and inadequately trained public health personnel can accelerate the transmission of infections, mostly zoonoses, in the post impact phase of the earthquake in Nepal. Therefore, we believe that with the support of aid agencies, veterinarians and health professionals can team up to resolve the crisis under One Health. Copyright © 2016 Ministry of Health, Saudi Arabia. Published by Elsevier Ltd. All rights reserved.

A moment in time: emergency nurses and the Canterbury earthquakes.

PubMed

Richardson, S; Ardagh, M; Grainger, P; Robinson, V

2013-06-01

To outline the impact of the Canterbury, New Zealand (NZ) earthquakes on Christchurch Hospital, and the experiences of emergency nurses during this time. NZ has experienced earthquakes and aftershocks centred in the Canterbury region of the South Island. The location of these, around and within the major city of Christchurch, was unexpected and associated with previously unknown fault lines. While the highest magnitude quake occurred in September 2010, registering 7.1 on the Richter scale, it was the magnitude 6.3 event on 22 February 2011 which was associated with the greatest injury burden and loss of life. Staff working in the only emergency department in the city were faced with an external emergency while also being directly affected as part of the disaster. SOURCES OF EVIDENCE: This paper developed following interviews with nurses who worked during this period, and draws on literature related to healthcare responses to earthquakes and natural disasters. The establishment of an injury database allowed for an accurate picture to emerge of the injury burden, and each of the authors was present and worked in a clinical capacity during the earthquake. Nurses played a significant role in the response to the earthquakes and its aftermath. However, little is known regarding the impact of this, either in personal or professional terms. This paper presents an overview of the earthquakes and experiences of nurses working during this time, identifying a range of issues that will benefit from further exploration and research. It seeks to provide a sense of the experiences and the potential meanings that were derived from being part of this 'moment in time'. Examples of innovations in practice emerged during the earthquake response and a number of recommendations for nursing practice are identified. © 2013 The Authors. International Nursing Review © 2013 International Council of Nurses.

THE GREAT SOUTHERN CALIFORNIA SHAKEOUT: Earthquake Science for 22 Million People

NASA Astrophysics Data System (ADS)

Jones, L.; Cox, D.; Perry, S.; Hudnut, K.; Benthien, M.; Bwarie, J.; Vinci, M.; Buchanan, M.; Long, K.; Sinha, S.; Collins, L.

2008-12-01

response technologies by Los Angeles Unified School District and a top to bottom examination of Los Angeles County Fire Department's earthquake response strategies.

Comparisons of Source Characteristics between Recent Inland Crustal Earthquake Sequences inside and outside of Niigata-Kobe Tectonic Zone, Japan

NASA Astrophysics Data System (ADS)

Somei, K.; Asano, K.; Iwata, T.; Miyakoshi, K.

2012-12-01

After the 1995 Kobe earthquake, many M7-class inland earthquakes occurred in Japan. Some of those events (e.g., the 2004 Chuetsu earthquake) occurred in a tectonic zone which is characterized as a high strain rate zone by the GPS observation (Sagiya et al., 2000) or dense distribution of active faults. That belt-like zone along the coast in Japan Sea side of Tohoku and Chubu districts, and north of Kinki district, is called as the Niigata-Kobe tectonic zone (NKTZ, Sagiya et al, 2000). We investigate seismic scaling relationship for recent inland crustal earthquake sequences in Japan and compare source characteristics between events occurring inside and outside of NKTZ. We used S-wave coda part for estimating source spectra. Source spectral ratio is obtained by S-wave coda spectral ratio between the records of large and small events occurring close to each other from nation-wide strong motion network (K-NET and KiK-net) and broad-band seismic network (F-net) to remove propagation-path and site effects. We carefully examined the commonality of the decay of coda envelopes between event-pair records and modeled the observed spectral ratio by the source spectral ratio function with assuming omega-square source model for large and small events. We estimated the corner frequencies and seismic moment (ratio) from those modeled spectral ratio function. We determined Brune's stress drops of 356 events (Mw: 3.1-6.9) in ten earthquake sequences occurring in NKTZ and six sequences occurring outside of NKTZ. Most of source spectra obey omega-square source spectra. There is no obvious systematic difference between stress drops of events in NKTZ zone and others. We may conclude that the systematic tendency of seismic source scaling of the events occurred inside and outside of NKTZ does not exist and the average source scaling relationship can be effective for inland crustal earthquakes. Acknowledgements: Waveform data were provided from K-NET, KiK-net and F-net operated by

A suite of exercises for verifying dynamic earthquake rupture codes

USGS Publications Warehouse

Harris, Ruth A.; Barall, Michael; Aagaard, Brad T.; Ma, Shuo; Roten, Daniel; Olsen, Kim B.; Duan, Benchun; Liu, Dunyu; Luo, Bin; Bai, Kangchen; Ampuero, Jean-Paul; Kaneko, Yoshihiro; Gabriel, Alice-Agnes; Duru, Kenneth; Ulrich, Thomas; Wollherr, Stephanie; Shi, Zheqiang; Dunham, Eric; Bydlon, Sam; Zhang, Zhenguo; Chen, Xiaofei; Somala, Surendra N.; Pelties, Christian; Tago, Josue; Cruz-Atienza, Victor Manuel; Kozdon, Jeremy; Daub, Eric; Aslam, Khurram; Kase, Yuko; Withers, Kyle; Dalguer, Luis

2018-01-01

We describe a set of benchmark exercises that are designed to test if computer codes that simulate dynamic earthquake rupture are working as intended. These types of computer codes are often used to understand how earthquakes operate, and they produce simulation results that include earthquake size, amounts of fault slip, and the patterns of ground shaking and crustal deformation. The benchmark exercises examine a range of features that scientists incorporate in their dynamic earthquake rupture simulations. These include implementations of simple or complex fault geometry, off‐fault rock response to an earthquake, stress conditions, and a variety of formulations for fault friction. Many of the benchmarks were designed to investigate scientific problems at the forefronts of earthquake physics and strong ground motions research. The exercises are freely available on our website for use by the scientific community.

The plan to coordinate NEHRP post-earthquake investigations

USGS Publications Warehouse

Holzer, Thomas L.; Borcherdt, Roger D.; Comartin, Craig D.; Hanson, Robert D.; Scawthorn, Charles R.; Tierney, Kathleen; Youd, T. Leslie

2003-01-01

This is the plan to coordinate domestic and foreign post-earthquake investigations supported by the National Earthquake Hazards Reduction Program (NEHRP). The plan addresses coordination of both the NEHRP agencies—Federal Emergency Management Agency (FEMA), National Institute of Standards and Technology (NIST), National Science Foundation (NSF), and U. S. Geological Survey (USGS)—and their partners. The plan is a framework for both coordinating what is going to be done and identifying responsibilities for post-earthquake investigations. It does not specify what will be done. Coordination is addressed in various time frames ranging from hours to years after an earthquake. The plan includes measures for (1) gaining rapid and general agreement on high-priority research opportunities, and (2) conducting the data gathering and fi eld studies in a coordinated manner. It deals with identifi cation, collection, processing, documentation, archiving, and dissemination of the results of post-earthquake work in a timely manner and easily accessible format.

Comparison of Ground Motion Prediction Equations (GMPE) for Chile and Canada With Recent Chilean Megathust Earthquakes

NASA Astrophysics Data System (ADS)

Herrera, C.; Cassidy, J. F.; Dosso, S. E.

2017-12-01

The ground shaking assessment allows quantifying the hazards associated with the occurrence of earthquakes. Chile and western Canada are two areas that have experienced, and are susceptible to imminent large crustal, in-slab and megathrust earthquakes that can affect the population significantly. In this context, we compare the current GMPEs used in the 2015 National Building Code of Canada and the most recent GMPEs calculated for Chile, with observed accelerations generated by four recent Chilean megathrust earthquakes (MW ≥ 7.7) that have occurred during the past decade, which is essential to quantify how well current models predict observations of major events.We collected the 3-component waveform data of more than 90 stations from the Centro Sismologico Nacional and the Universidad de Chile, and processed them by removing the trend and applying a band-pass filter. Then, for each station, we obtained the Peak Ground Acceleration (PGA), and by using a damped response spectra, we calculated the Pseudo Spectral Acceleration (PSA). Finally, we compared those observations with the most recent Chilean and Canadian GMPEs. Given the lack of geotechnical information for most of the Chilean stations, we also used a new method to obtain the VS30 by inverting the H/V ratios using a trans-dimensional Bayesian inversion, which allows us to improve the correction of observations according to soil conditions.As expected, our results show a good fit between observations and the Chilean GMPEs, but we observe that although the shape of the Canadian GMPEs is coherent with the distribution of observations, in general they under predict the observations for PGA and PSA at shorter periods for most of the considered earthquakes. An example of this can be seen in the attached figure for the case of the 2014 Iquique earthquake.These results present important implications related to the hazards associated to large earthquakes, especially for western Canada, where the probability of a

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 ...

The EM Earthquake Precursor

NASA Astrophysics Data System (ADS)

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

2013-12-01

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

Rapid estimation of the economic consequences of global earthquakes

USGS Publications Warehouse

Jaiswal, Kishor; Wald, David J.

2011-01-01

The U.S. Geological Survey's (USGS) Prompt Assessment of Global Earthquakes for Response (PAGER) system, operational since mid 2007, rapidly estimates the most affected locations and the population exposure at different levels of shaking intensities. The PAGER system has significantly improved the way aid agencies determine the scale of response needed in the aftermath of an earthquake. For example, the PAGER exposure estimates provided reasonably accurate assessments of the scale and spatial extent of the damage and losses following the 2008 Wenchuan earthquake (Mw 7.9) in China, the 2009 L'Aquila earthquake (Mw 6.3) in Italy, the 2010 Haiti earthquake (Mw 7.0), and the 2010 Chile earthquake (Mw 8.8). Nevertheless, some engineering and seismological expertise is often required to digest PAGER's exposure estimate and turn it into estimated fatalities and economic losses. This has been the focus of PAGER's most recent development. With the new loss-estimation component of the PAGER system it is now possible to produce rapid estimation of expected fatalities for global earthquakes (Jaiswal and others, 2009). While an estimate of earthquake fatalities is a fundamental indicator of potential human consequences in developing countries (for example, Iran, Pakistan, Haiti, Peru, and many others), economic consequences often drive the responses in much of the developed world (for example, New Zealand, the United States, and Chile), where the improved structural behavior of seismically resistant buildings significantly reduces earthquake casualties. Rapid availability of estimates of both fatalities and economic losses can be a valuable resource. The total time needed to determine the actual scope of an earthquake disaster and to respond effectively varies from country to country. It can take days or sometimes weeks before the damage and consequences of a disaster can be understood both socially and economically. The objective of the U.S. Geological Survey's PAGER system is

Protracted fluvial recovery from medieval earthquakes, Pokhara, Nepal

NASA Astrophysics Data System (ADS)

Stolle, Amelie; Bernhardt, Anne; Schwanghart, Wolfgang; Andermann, Christoff; Schönfeldt, Elisabeth; Seidemann, Jan; Adhikari, Basanta R.; Merchel, Silke; Rugel, Georg; Fort, Monique; Korup, Oliver

2016-04-01

River response to strong earthquake shaking in mountainous terrain often entails the flushing of sediments delivered by widespread co-seismic landsliding. Detailed mass-balance studies following major earthquakes in China, Taiwan, and New Zealand suggest fluvial recovery times ranging from several years to decades. We report a detailed chronology of earthquake-induced valley fills in the Pokhara region of western-central Nepal, and demonstrate that rivers continue to adjust to several large medieval earthquakes to the present day, thus challenging the notion of transient fluvial response to seismic disturbance. The Pokhara valley features one of the largest and most extensively dated sedimentary records of earthquake-triggered sedimentation in the Himalayas, and independently augments paleo-seismological archives obtained mainly from fault trenches and historic documents. New radiocarbon dates from the catastrophically deposited Pokhara Formation document multiple phases of extremely high geomorphic activity between ˜700 and ˜1700 AD, preserved in thick sequences of alternating fluvial conglomerates, massive mud and silt beds, and cohesive debris-flow deposits. These dated fan-marginal slackwater sediments indicate pronounced sediment pulses in the wake of at least three large medieval earthquakes in ˜1100, 1255, and 1344 AD. We combine these dates with digital elevation models, geological maps, differential GPS data, and sediment logs to estimate the extent of these three pulses that are characterized by sedimentation rates of ˜200 mm yr-1 and peak rates as high as 1,000 mm yr-1. Some 5.5 to 9 km3 of material infilled the pre-existing topography, and is now prone to ongoing fluvial dissection along major canyons. Contemporary river incision into the Pokhara Formation is rapid (120-170 mm yr-1), triggering widespread bank erosion, channel changes, and very high sediment yields of the order of 103 to 105 t km-2 yr-1, that by far outweigh bedrock denudation rates

A Full Dynamic Compound Inverse Method for output-only element-level system identification and input estimation from earthquake response signals

NASA Astrophysics Data System (ADS)

Pioldi, Fabio; Rizzi, Egidio

2016-08-01

This paper proposes a new output-only element-level system identification and input estimation technique, towards the simultaneous identification of modal parameters, input excitation time history and structural features at the element-level by adopting earthquake-induced structural response signals. The method, named Full Dynamic Compound Inverse Method (FDCIM), releases strong assumptions of earlier element-level techniques, by working with a two-stage iterative algorithm. Jointly, a Statistical Average technique, a modification process and a parameter projection strategy are adopted at each stage to achieve stronger convergence for the identified estimates. The proposed method works in a deterministic way and is completely developed in State-Space form. Further, it does not require continuous- to discrete-time transformations and does not depend on initialization conditions. Synthetic earthquake-induced response signals from different shear-type buildings are generated to validate the implemented procedure, also with noise-corrupted cases. The achieved results provide a necessary condition to demonstrate the effectiveness of the proposed identification method.

A hypothesis for delayed dynamic earthquake triggering

USGS Publications Warehouse

Parsons, T.

2005-01-01

It's uncertain whether more near-field earthquakes are triggered by static or dynamic stress changes. This ratio matters because static earthquake interactions are increasingly incorporated into probabilistic forecasts. Recent studies were unable to demonstrate all predictions from the static-stress-change hypothesis, particularly seismicity rate reductions. However, current dynamic stress change hypotheses do not explain delayed earthquake triggering and Omori's law. Here I show numerically that if seismic waves can alter some frictional contacts in neighboring fault zones, then dynamic triggering might cause delayed triggering and an Omori-law response. The hypothesis depends on faults following a rate/state friction law, and on seismic waves changing the mean critical slip distance (Dc) at nucleation zones.

A study of Guptkashi, Uttarakhand earthquake of 6 February 2017 ( M w 5.3) in the Himalayan arc and implications for ground motion estimation

NASA Astrophysics Data System (ADS)

Srinagesh, Davuluri; Singh, Shri Krishna; Suresh, Gaddale; Srinivas, Dakuri; Pérez-Campos, Xyoli; Suresh, Gudapati

2018-05-01

The 2017 Guptkashi earthquake occurred in a segment of the Himalayan arc with high potential for a strong earthquake in the near future. In this context, a careful analysis of the earthquake is important as it may shed light on source and ground motion characteristics during future earthquakes. Using the earthquake recording on a single broadband strong-motion seismograph installed at the epicenter, we estimate the earthquake's location (30.546° N, 79.063° E), depth ( H = 19 km), the seismic moment ( M 0 = 1.12×1017 Nm, M w 5.3), the focal mechanism ( φ = 280°, δ = 14°, λ = 84°), the source radius ( a = 1.3 km), and the static stress drop (Δ σ s 22 MPa). The event occurred just above the Main Himalayan Thrust. S-wave spectra of the earthquake at hard sites in the arc are well approximated (assuming ω -2 source model) by attenuation parameters Q( f) = 500 f 0.9, κ = 0.04 s, and f max = infinite, and a stress drop of Δ σ = 70 MPa. Observed and computed peak ground motions, using stochastic method along with parameters inferred from spectral analysis, agree well with each other. These attenuation parameters are also reasonable for the observed spectra and/or peak ground motion parameters in the arc at distances ≤ 200 km during five other earthquakes in the region (4.6 ≤ M w ≤ 6.9). The estimated stress drop of the six events ranges from 20 to 120 MPa. Our analysis suggests that attenuation parameters given above may be used for ground motion estimation at hard sites in the Himalayan arc via the stochastic method.

A study of Guptkashi, Uttarakhand earthquake of 6 February 2017 (M w 5.3) in the Himalayan arc and implications for ground motion estimation

NASA Astrophysics Data System (ADS)

Srinagesh, Davuluri; Singh, Shri Krishna; Suresh, Gaddale; Srinivas, Dakuri; Pérez-Campos, Xyoli; Suresh, Gudapati

2018-02-01

The 2017 Guptkashi earthquake occurred in a segment of the Himalayan arc with high potential for a strong earthquake in the near future. In this context, a careful analysis of the earthquake is important as it may shed light on source and ground motion characteristics during future earthquakes. Using the earthquake recording on a single broadband strong-motion seismograph installed at the epicenter, we estimate the earthquake's location (30.546° N, 79.063° E), depth (H = 19 km), the seismic moment (M 0 = 1.12×1017 Nm, M w 5.3), the focal mechanism (φ = 280°, δ = 14°, λ = 84°), the source radius (a = 1.3 km), and the static stress drop (Δσ s 22 MPa). The event occurred just above the Main Himalayan Thrust. S-wave spectra of the earthquake at hard sites in the arc are well approximated (assuming ω -2 source model) by attenuation parameters Q(f) = 500f 0.9, κ = 0.04 s, and f max = infinite, and a stress drop of Δσ = 70 MPa. Observed and computed peak ground motions, using stochastic method along with parameters inferred from spectral analysis, agree well with each other. These attenuation parameters are also reasonable for the observed spectra and/or peak ground motion parameters in the arc at distances ≤ 200 km during five other earthquakes in the region (4.6 ≤ M w ≤ 6.9). The estimated stress drop of the six events ranges from 20 to 120 MPa. Our analysis suggests that attenuation parameters given above may be used for ground motion estimation at hard sites in the Himalayan arc via the stochastic method.

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

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.

Application and evaluation of a rapid response earthquake-triggered landslide model to the 25 April 2015 Mw 7.8 Gorkha earthquake, Nepal

USGS Publications Warehouse

Gallen, Sean F.; Clark, Marin K.; Godt, Jonathan W.; Roback, Kevin; Niemi, Nathan A

2017-01-01

The 25 April 2015 Mw 7.8 Gorkha earthquake produced strong ground motions across an approximately 250 km by 100 km swath in central Nepal. To assist disaster response activities, we modified an existing earthquake-triggered landslide model based on a Newmark sliding block analysis to estimate the extent and intensity of landsliding and landslide dam hazard. Landslide hazard maps were produced using Shuttle Radar Topography Mission (SRTM) digital topography, peak ground acceleration (PGA) information from the U.S. Geological Survey (USGS) ShakeMap program, and assumptions about the regional rock strength based on end-member values from previous studies. The instrumental record of seismicity in Nepal is poor, so PGA estimates were based on empirical Ground Motion Prediction Equations (GMPEs) constrained by teleseismic data and felt reports. We demonstrate a non-linear dependence of modeled landsliding on aggregate rock strength, where the number of landslides decreases exponentially with increasing rock strength. Model estimates are less sensitive to PGA at steep slopes (> 60°) compared to moderate slopes (30–60°). We compare forward model results to an inventory of landslides triggered by the Gorkha earthquake. We show that moderate rock strength inputs over estimate landsliding in regions beyond the main slip patch, which may in part be related to poorly constrained PGA estimates for this event at far distances from the source area. Directly above the main slip patch, however, the moderate strength model accurately estimates the total number of landslides within the resolution of the model (landslides ≥ 0.0162 km2; observed n = 2214, modeled n = 2987), but the pattern of landsliding differs from observations. This discrepancy is likely due to the unaccounted for effects of variable material strength and local topographic amplification of strong ground motion, as well as other simplifying assumptions about source characteristics and their

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

USGS Publications Warehouse

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

1992-01-01

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

Source spectral properties of small-to-moderate earthquakes in southern Kansas

USGS Publications Warehouse

Trugman, Daniel T.; Dougherty, Sara L.; Cochran, Elizabeth S.; Shearer, Peter M.

2017-01-01

The source spectral properties of injection-induced earthquakes give insight into their nucleation, rupture processes, and influence on ground motion. Here we apply a spectral decomposition approach to analyze P-wave spectra and estimate Brune-type stress drop for more than 2000 ML1.5–5.2 earthquakes occurring in southern Kansas from 2014 to 2016. We find that these earthquakes are characterized by low stress drop values (median ∼0.4MPa) compared to natural seismicity in California. We observe a significant increase in stress drop as a function of depth, but the shallow depth distribution of these events is not by itself sufficient to explain their lower stress drop. Stress drop increases with magnitude from M1.5–M3.5, but this scaling trend may weaken above M4 and also depends on the assumed source model. Although we observe a nonstationary, sequence-specific temporal evolution in stress drop, we find no clear systematic relation with the activity of nearby injection wells.

Design and application of the emergency response mobile phone-based information system for infectious disease reporting in the Wenchuan earthquake zone.

PubMed

Ma, Jiaqi; Zhou, Maigeng; Li, Yanfei; Guo, Yan; Su, Xuemei; Qi, Xiaopeng; Ge, Hui

2009-05-01

To describe the design and application of an emergency response mobile phone-based information system for infectious disease reporting. Software engineering and business modeling were used to design and develop the emergency response mobile phone-based information system for infectious disease reporting. Seven days after the initiation of the reporting system, the reporting rate in the earthquake zone reached the level of the same period in 2007, using the mobile phone-based information system. Surveillance of the weekly report on morbidity in the earthquake zone after the initiation of the mobile phone reporting system showed the same trend as the previous three years. The emergency response mobile phone-based information system for infectious disease reporting was an effective solution to transmit urgently needed reports and manage communicable disease surveillance information. This assured the consistency of disease surveillance and facilitated sensitive, accurate, and timely disease surveillance. It is an important backup for the internet-based direct reporting system for communicable disease. © 2009 Blackwell Publishing Asia Pty Ltd and Chinese Cochrane Center, West China Hospital of Sichuan University.

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.

Damages from the 20 September earthquakes near Klamath Falls, Oregon

USGS Publications Warehouse

Dewey, J.W.

1993-01-01

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

Earthquake insurance pricing: a risk-based approach.

PubMed

Lin, Jeng-Hsiang

2018-04-01

Flat earthquake premiums are 'uniformly' set for a variety of buildings in many countries, neglecting the fact that the risk of damage to buildings by earthquakes is based on a wide range of factors. How these factors influence the insurance premiums is worth being studied further. Proposed herein is a risk-based approach to estimate the earthquake insurance rates of buildings. Examples of application of the approach to buildings located in Taipei city of Taiwan were examined. Then, the earthquake insurance rates for the buildings investigated were calculated and tabulated. To fulfil insurance rating, the buildings were classified into 15 model building types according to their construction materials and building height. Seismic design levels were also considered in insurance rating in response to the effect of seismic zone and construction years of buildings. This paper may be of interest to insurers, actuaries, and private and public sectors of insurance. © 2018 The Author(s). Disasters © Overseas Development Institute, 2018.

The postseismic response to the 2002 M 7.9 Denali Fault earthquake: Constraints from InSAR 2003-2005

USGS Publications Warehouse

Biggs, J.; Burgmann, R.; Freymueller, J.T.; Lu, Z.; Parsons, B.; Ryder, I.; Schmalzle, G.; Wright, Tim

2009-01-01

InSAR is particularly sensitive to vertical displacements, which can be important in distinguishing between mechanisms responsible for the postseismic response to large earthquakes (afterslip, viscoelastic relaxation). We produce maps of the surface displacements resulting from the postseismic response to the 2002 Denali Fault earthquake, using data from the Canadian Radarsat-1 satellite from the periods summer 2003, summer 2004 and summer 2005. A peak-to-trough signal of amplitude 4 cm in the satellite line of sight was observed between summer 2003 and summer 2004. By the period between summer 2004 and summer 2005, the displacement rate had dropped below the threshold required for observation with InSAR over a single year. The InSAR observations show that the principal postseismic relaxation process acted at a depth of ∼50 km, equivalent to the top of the mantle. However, the observations are still incapable of distinguishing between distributed (viscoelastic relaxation) and localized (afterslip) deformation. The imposed coseismic stresses are highest in the lower crust and, assuming a Maxwell rheology, a viscosity ratio of at least 5 between lower crust and upper mantle is required to explain the contrast in behaviour. The lowest misfits are produced by mixed models of viscoelastic relaxation in the mantle and shallow afterslip in the upper crust. Profiles perpendicular to the fault show significant asymmetry, which is consistent with differences in rheological structure across the fault.

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

NASA Technical Reports Server (NTRS)

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

Strong-motion data from the two Pingtung, Taiwan, earthquakes of 26 December 2006

USGS Publications Warehouse

Wu, C.-F.; Lee, W.H.K.; Boore, D.M.

2008-01-01

1016 strong-motion records at 527 free-field stations and 131 records at 42 strong-motion arrays at buildings and bridges were obtained for the Pingtung earthquake doublet from the Taiwan Central Weather Bureau's dense, digital strong-motion network. We carried out standard processing of these strong-motion records at free-field stations. A data set, including the originally recorded files, processed data files, and supporting software and information, is archived online http:// tecdc.earth.sinica.edu.tw/data/EQ2006Pingtung/. We have not yet completed the processing of the strong-motion array data at buildings and bridges. However, some preliminary results and the strong-motion array data recorded at the second nearest instrumented building to the Pingtung earthquake doublet are shown. This paper is intended to document our data processing procedures and the online archived data files, so that researchers can efficiently use the data. We also include two preliminary analyses: (1) a comparison of ground motions recorded by multiple accelerographs at a common site, the TAP 117 station in Taipei, and (2) attenuation of the horizontal ground motions (peak acceleration and response spectra at periods of 0.2, 1.0, and 3.0 s) with respect to distance. Our comparison study of multiple recordings at TAP 117 indicates that waveform coherence among 20- and 24-bit accelerograph records is much higher as compared to records from 16-bit or 12-bit accelerographs, suggesting that the former are of better quality. For the 20- and 24-bit accelerographs, waveform coherence is nearly 1 over the frequency range 1 to 8 Hz for all components, and is greater than about 0.9 from 8 to 20 Hz for the horizontal component, but only from 8 to 12 Hz for the vertical component. Plots of pseudo-acceleration response spectra (PSA) as a function of distance, however, show no clear indication for a difference related to the performance level of the accelerographs. The ground-motions of the first

Analog earthquakes

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

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

NASA Applied Sciences Disasters Program Support for the September 2017 Mexico Earthquakes

NASA Astrophysics Data System (ADS)

Glasscoe, M. T.; Kirschbaum, D.; Torres-Perez, J. L.; Yun, S. H.; Owen, S. E.; Hua, H.; Fielding, E. J.; Liang, C.; Bekaert, D. P.; Osmanoglu, B.; Amini, R.; Green, D. S.; Murray, J. J.; Stough, T.; Struve, J. C.; Seepersad, J.; Thompson, V.

2017-12-01

The 8 September M 8.1 Tehuantepec and 19 September M 7.1 Puebla earthquakes were among the largest earthquakes recorded in Mexico. These two events caused widespread damage, affecting several million people and causing numerous casualties. A team of event coordinators in the NASA Applied Sciences Program activated soon after these devastating earthquakes in order to support decision makers in Mexico, using NASA modeling and international remote sensing capabilities to generate decision support products to aid in response and recovery. The NASA Disasters Program promotes the use of Earth observations to improve the prediction of, preparation for, response to, and recovery from natural and technological disasters. For these two events, the Disasters Program worked with Mexico's space agency (Agencia Espacial Mexico, AEM) and the National Center for Prevention of Disasters (Centro Nacional de Prevención de Desastres, CENAPRED) to generate products to support response, decision-making, and recovery. Products were also provided to academic partners, technical institutions, and field responders to support response. In addition, the Program partnered with the US Geological Survey (USGS), Office of Foreign Disaster Assistance (OFDA), and other partners in order to provide information to federal and domestic agencies that were supporting event response. Leveraging the expertise of investigators at NASA Centers, products such as landslide susceptibility maps, precipitation models, and radar based damage assessments and surface deformation maps were generated and used by AEM, CENAPRED, and others during the event. These were used by AEM in collaboration with other government agencies in Mexico to make appropriate decisions for mapping damage, rescue and recovery, and informing the population regarding areas prone to potential risk. We will provide an overview of the response activities and data products generated in support of the earthquake response, partnerships with

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

USGS Publications Warehouse

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

2017-01-01

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

Landslides and Earthquake Lakes from the Wenchuan, China Earthquake - Can it Happen in the U.S.?

NASA Astrophysics Data System (ADS)

Stenner, H.; Cydzik, K.; Hamilton, D.; Cattarossi, A.; Mathieson, E.

2008-12-01

The May 12, 2008 M7.9 Wenchuan, China earthquake destroyed five million homes and schools, causing over 87,650 deaths. Landslides, a secondary effect of the shaking, caused much of the devastation. Debris flows buried homes, rock falls crushed cars, and landslides dammed rivers. Blocked roads greatly impeded emergency access, delaying response. Our August 2008 field experience in the affected area reminded us that the western United States faces serious risks posed by earthquake-induced landslides. The topography of the western U.S. is less extreme than that near Wenchuan, but earthquakes may still cause devastating landslides, damming rivers and blocking access to affected areas. After the Wenchuan earthquake, lakes rapidly rose behind landslide dams, threatening millions of lives. One landslide above Beichuan City created Tangjiashan Lake, a massive body of water upstream of Mianyang, an area with 5.2 million people, 30,000 of whom were killed in the quake. Potential failure of the landslide dam put thousands more people at risk from catastrophic flooding. In 1959, the M7.4 Hebgen Lake earthquake in Montana caused a large landslide, which killed 19 people and dammed the Madison River. The Army Corps excavated sluices to keep the dam from failing catastrophically. The Hebgen Lake earthquake ultimately caused 28 deaths, mostly from landslides, but the affected region was sparsely populated. Slopes prone to strong earthquake shaking and landslides in California, Washington, and Oregon have much larger populations at risk. Landslide hazards continue after the earthquake due to the effect strong shaking has on hillslopes, particularly when subjected to subsequent rain. These hazards must be taken into account. Once a landslide blocks a river, rapid and thoughtful action is needed. The Chinese government quickly and safely mitigated landslide dams that posed the greatest risk to people downstream. It took expert geotechnical advice, the speed and resources of the army

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.

Water-level changes induced by local and distant earthquakes at Long Valley caldera, California

USGS Publications Warehouse

Roeloffs, Evelyn A.; Sneed, Michelle; Galloway, Devin L.; Sorey, Michael L.; Farrar, Christopher D.; Howle, James F.; Hughes, J.

2003-01-01

Distant as well as local earthquakes have induced groundwater-level changes persisting for days to weeks at Long Valley caldera, California. Four wells open to formations as deep as 300 m have responded to 16 earthquakes, and responses to two earthquakes in the 3-km-deep Long Valley Exploratory Well (LVEW) show that these changes are not limited to weathered or unconsolidated near-surface rocks. All five wells exhibit water-level variations in response to earth tides, indicating they can be used as low-resolution strainmeters. Earthquakes induce gradual water-level changes that increase in amplitude for as long as 30 days, then return more slowly to pre-earthquake levels. The gradual water-level changes are always drops at wells LKT, LVEW, and CH-10B, and always rises at well CW-3. At a dilatometer just outside the caldera, earthquake-induced strain responses consist of either a step followed by a contractional strain-rate increase, or a transient contractional signal that reaches a maximum in about seven days and then returns toward the pre-earthquake value. The sizes of the gradual water-level changes generally increase with earthquake magnitude and decrease with hypocentral distance. Local earthquakes in Long Valley produce coseismic water-level steps; otherwise the responses to local earthquakes and distant earthquakes are indistinguishable. In particular, water-level and strain changes in Long Valley following the 1992 M7.3 Landers earthquake, 450 km distant, closely resemble those initiated by a M4.9 local earthquake on November 22, 1997, during a seismic swarm with features indicative of fluid involvement. At the LKT well, many of the response time histories are identical for 20 days after each earthquake, and can be matched by a theoretical solution giving the pore pressure as a function of time due to diffusion of a nearby, instantaneous, pressure drop. Such pressure drops could be produced by accelerated inflation of the resurgent dome by amounts too

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

On the Potential Uses of Static Offsets Derived From Low-Cost Community Instruments and Crowd-Sourcing for Earthquake Monitoring and Rapid Response

NASA Astrophysics Data System (ADS)

Minson, S. E.; Brooks, B. A.; Murray, J. R.; Iannucci, R. A.

2013-12-01

We explore the efficacy of low-cost community instruments (LCCIs) and crowd-sourcing to produce rapid estimates of earthquake magnitude and rupture characteristics which can be used for earthquake loss reduction such as issuing tsunami warnings and guiding rapid response efforts. Real-time high-rate GPS data are just beginning to be incorporated into earthquake early warning (EEW) systems. These data are showing promising utility including producing moment magnitude estimates which do not saturate for the largest earthquakes and determining the geometry and slip distribution of the earthquake rupture in real-time. However, building a network of scientific-quality real-time high-rate GPS stations requires substantial infrastructure investment which is not practicable in many parts of the world. To expand the benefits of real-time geodetic monitoring globally, we consider the potential of pseudorange-based GPS locations such as the real-time positioning done onboard cell phones or on LCCIs that could be distributed in the same way accelerometers are distributed as part of the Quake Catcher Network (QCN). While location information from LCCIs often have large uncertainties, their low cost means that large numbers of instruments can be deployed. A monitoring network that includes smartphones could collect data from potentially millions of instruments. These observations could be averaged together to substantially decrease errors associated with estimated earthquake source parameters. While these data will be inferior to data recorded by scientific-grade seismometers and GPS instruments, there are features of community-based data collection (and possibly analysis) that are very attractive. This approach creates a system where every user can host an instrument or download an application to their smartphone that both provides them with earthquake and tsunami warnings while also providing the data on which the warning system operates. This symbiosis helps to encourage

Development of Earthquake Emergency Response Plan for Tribhuvan International Airport, Kathmandu, Nepal

DTIC Science & Technology

2013-02-01

Kathmandu, Nepal 5a. CONTRACT NUMBER W911NF-12-1-0282 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d. PROJECT NUMBER 5e. TASK NUMBER ...In the past, big earthquakes in Nepal (see Figure 1.1) have caused a huge number of casualties and damage to structures. The Great Nepal -Bihar...UBC Earthquake Engineering Research Facility 2235 East Mall, Vancouver, BC, Canada V6T 1Z4 Phone : 604 822-6203 Fax: 604 822-6901 E-mail

Predictors of psychological resilience amongst medical students following major earthquakes.

PubMed

Carter, Frances; Bell, Caroline; Ali, Anthony; McKenzie, Janice; Boden, Joseph M; Wilkinson, Timothy; Bell, Caroline

2016-05-06

To identify predictors of self-reported psychological resilience amongst medical students following major earthquakes in Canterbury in 2010 and 2011. Two hundred and fifty-three medical students from the Christchurch campus, University of Otago, were invited to participate in an electronic survey seven months following the most severe earthquake. Students completed the Connor-Davidson Resilience Scale, the Depression, Anxiety and Stress Scale, the Post-traumatic Disorder Checklist, the Work and Adjustment Scale, and the Eysenck Personality Questionnaire. Likert scales and other questions were also used to assess a range of variables including demographic and historical variables (eg, self-rated resilience prior to the earthquakes), plus the impacts of the earthquakes. The response rate was 78%. Univariate analyses identified multiple variables that were significantly associated with higher resilience. Multiple linear regression analyses produced a fitted model that was able to explain 35% of the variance in resilience scores. The best predictors of higher resilience were: retrospectively-rated personality prior to the earthquakes (higher extroversion and lower neuroticism); higher self-rated resilience prior to the earthquakes; not being exposed to the most severe earthquake; and less psychological distress following the earthquakes. Psychological resilience amongst medical students following major earthquakes was able to be predicted to a moderate extent.

Experimental results of temperature response to stress change: An indication of the physics of earthquake rupture propagation

NASA Astrophysics Data System (ADS)

Lin, W.; Yang, X.; Tadai, O.; Zeng, X.; Yeh, E. C.; Yu, C.; Hatakeda, K.; Xu, H.; Xu, Z.

2016-12-01

As a result of the earthquake rupture propagation, stress on the earthquake fault and in the hanging wall and in the footwall coseismically drops. Based on the thermo-elasticity theory, the temperature of rocks may change associated with coseismic stress change at the same time as their elastic deformation. This coseismic temperature change is one of the physics of earthquake rupture propagation, however has not been noted and expressly addressed before. To understand this temperature issue, we conducted laboratory experiments to quantitatively investigate temperatures response of rocks to rapid stress change of various typical rocks. Consequently, we developed a hydrostatic compression experimental equipment for rock samples with a high resolution temperature measuring system. This enable us to rapidly load and/or unload the confining pressure. As experimental rock samples, we collected 15 representative rocks from various scientific drilling projects and outcrops of earthquake faults, and quarries in the world. The rock types include sandstone, siltstone, limestone, granite, basalt, tuff etc. Based on the classical thermo-elastic theory, a conventional relationship between the temperature change (dT) of rock samples and the confining pressure change (dP) in the hydrostatic compression system under adiabatic condition can be expressed as a linear function. Therefore, we can measure the adiabatic pressure derivative of temperature (dT/dP) directly by monitoring changes of rock sample temperature and confining pressure during the rapidly loading and unloading processes. As preliminary results of the experiments, the data of 15 rock samples showed that i) the adiabatic pressure derivative of temperature (dT/dP) of most rocks are about 1.5 6.2 mK/MPa; ii) the dT/dP of sedimentary rocks is larger than igneous and metamorphic rocks; iii) a good linear correlation between dT/dP and the rock's bulk modulus was recognized.

Fluid‐driven seismicity response of the Rinconada fault near Paso Robles, California, to the 2003 M 6.5 San Simeon earthquake

USGS Publications Warehouse

Hardebeck, Jeanne L.

2012-01-01

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

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

NASA Astrophysics Data System (ADS)

Ide, Satoshi; Yabe, Suguru; Tanaka, Yoshiyuki

2016-11-01

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

Practical Applications for Earthquake Scenarios Using ShakeMap

NASA Astrophysics Data System (ADS)

Wald, D. J.; Worden, B.; Quitoriano, V.; Goltz, J.

2001-12-01

In planning and coordinating emergency response, utilities, local government, and other organizations are best served by conducting training exercises based on realistic earthquake situations-ones that they are most likely to face. Scenario earthquakes can fill this role; they can be generated for any geologically plausible earthquake or for actual historic earthquakes. ShakeMap Web pages now display selected earthquake scenarios (www.trinet.org/shake/archive/scenario/html) and more events will be added as they are requested and produced. We will discuss the methodology and provide practical examples where these scenarios are used directly for risk reduction. Given a selected event, we have developed tools to make it relatively easy to generate a ShakeMap earthquake scenario using the following steps: 1) Assume a particular fault or fault segment will (or did) rupture over a certain length, 2) Determine the magnitude of the earthquake based on assumed rupture dimensions, 3) Estimate the ground shaking at all locations in the chosen area around the fault, and 4) Represent these motions visually by producing ShakeMaps and generating ground motion input for loss estimation modeling (e.g., FEMA's HAZUS). At present, ground motions are estimated using empirical attenuation relationships to estimate peak ground motions on rock conditions. We then correct the amplitude at that location based on the local site soil (NEHRP) conditions as we do in the general ShakeMap interpolation scheme. Finiteness is included explicitly, but directivity enters only through the empirical relations. Although current ShakeMap earthquake scenarios are empirically based, substantial improvements in numerical ground motion modeling have been made in recent years. However, loss estimation tools, HAZUS for example, typically require relatively high frequency (3 Hz) input for predicting losses, above the range of frequencies successfully modeled to date. Achieving full-synthetic ground motion

Earthquake Education in Prime Time

NASA Astrophysics Data System (ADS)

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

2004-12-01

hazard response to create a program that is both educational and provides a public service. Seismic Sleuths and Written in Stone are the harbingers of a new genre of earthquake programs that are the antithesis of the 1974 film Earthquake and the 2004 miniseries 10.5. Film producers and those in the earthquake education community are demonstrating that it is possible to tell an exciting story, inspire awareness, and encourage empowerment without sensationalism.

USGS Imagery Applications During Disaster Response After Recent Earthquakes

NASA Astrophysics Data System (ADS)

Hudnut, K. W.; Brooks, B. A.; Glennie, C. L.; Finnegan, D. C.

2015-12-01

It is not only important to rapidly characterize surface fault rupture and related ground deformation after an earthquake, but also to repeatedly make observations following an event to forecast fault afterslip. These data may also be used by other agencies to monitor progress on damage repairs and restoration efforts by emergency responders and the public. Related requirements include repeatedly obtaining reference or baseline imagery before a major disaster occurs, as well as maintaining careful geodetic control on all imagery in a time series so that absolute georeferencing may be applied to the image stack through time. In addition, repeated post-event imagery acquisition is required, generally at a higher repetition rate soon after the event, then scaled back to less frequent acquisitions with time, to capture phenomena (such as fault afterslip) that are known to have rates that decrease rapidly with time. For example, lidar observations acquired before and after the South Napa earthquake of 2014, used in our extensive post-processing work that was funded primarily by FEMA, aided in the accurate forecasting of fault afterslip. Lidar was used to independently validate and verify the official USGS afterslip forecast. In order to keep pace with rapidly evolving technology, a development pipeline must be established and maintained to continually test and incorporate new sensors, while adapting these new components to the existing platform and linking them to the existing base software system, and then sequentially testing the system as it evolves. Improvements in system performance by incremental upgrades of system components and software are essential. Improving calibration parameters and thereby progressively eliminating artifacts requires ongoing testing, research and development. To improve the system, we have formed an interdisciplinary team with common interests and diverse sources of support. We share expertise and leverage funding while effectively and

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.

U.S. Geological Survey (USGS) Earthquake Web Applications

NASA Astrophysics Data System (ADS)

Fee, J.; Martinez, E.

2015-12-01

USGS Earthquake web applications provide access to earthquake information from USGS and other Advanced National Seismic System (ANSS) contributors. One of the primary goals of these applications is to provide a consistent experience for accessing both near-real time information as soon as it is available and historic information after it is thoroughly reviewed. Millions of people use these applications every month including people who feel an earthquake, emergency responders looking for the latest information about a recent event, and scientists researching historic earthquakes and their effects. Information from multiple catalogs and contributors is combined by the ANSS Comprehensive Catalog into one composite catalog, identifying the most preferred information from any source for each event. A web service and near-real time feeds provide access to all contributed data, and are used by a number of users and software packages. The Latest Earthquakes application displays summaries of many events, either near-real time feeds or custom searches, and the Event Page application shows detailed information for each event. Because all data is accessed through the web service, it can also be downloaded by users. The applications are maintained as open source projects on github, and use mobile-first and responsive-web-design approaches to work well on both mobile devices and desktop computers. http://earthquake.usgs.gov/earthquakes/map/

Tectonic summaries of magnitude 7 and greater earthquakes from 2000 to 2015

USGS Publications Warehouse

Hayes, Gavin P.; Meyers, Emma K.; Dewey, James W.; Briggs, Richard W.; Earle, Paul S.; Benz, Harley M.; Smoczyk, Gregory M.; Flamme, Hanna E.; Barnhart, William D.; Gold, Ryan D.; Furlong, Kevin P.

2017-01-11

This paper describes the tectonic summaries for all magnitude 7 and larger earthquakes in the period 2000–2015, as produced by the U.S. Geological Survey National Earthquake Information Center during their routine response operations to global earthquakes. The goal of such summaries is to provide important event-specific information to the public rapidly and concisely, such that recent earthquakes can be understood within a global and regional seismotectonic framework. We compile these summaries here to provide a long-term archive for this information, and so that the variability in tectonic setting and earthquake history from region to region, and sometimes within a given region, can be more clearly understood.

Rapid Modeling of and Response to Large Earthquakes Using Real-Time GPS Networks (Invited)

NASA Astrophysics Data System (ADS)

Crowell, B. W.; Bock, Y.; Squibb, M. B.

2010-12-01

Real-time GPS networks have the advantage of capturing motions throughout the entire earthquake cycle (interseismic, seismic, coseismic, postseismic), and because of this, are ideal for real-time monitoring of fault slip in the region. Real-time GPS networks provide the perfect supplement to seismic networks, which operate with lower noise and higher sampling rates than GPS networks, but only measure accelerations or velocities, putting them at a supreme disadvantage for ascertaining the full extent of slip during a large earthquake in real-time. Here we report on two examples of rapid modeling of recent large earthquakes near large regional real-time GPS networks. The first utilizes Japan’s GEONET consisting of about 1200 stations during the 2003 Mw 8.3 Tokachi-Oki earthquake about 100 km offshore Hokkaido Island and the second investigates the 2010 Mw 7.2 El Mayor-Cucapah earthquake recorded by more than 100 stations in the California Real Time Network. The principal components of strain were computed throughout the networks and utilized as a trigger to initiate earthquake modeling. Total displacement waveforms were then computed in a simulated real-time fashion using a real-time network adjustment algorithm that fixes a station far away from the rupture to obtain a stable reference frame. Initial peak ground displacement measurements can then be used to obtain an initial size through scaling relationships. Finally, a full coseismic model of the event can be run minutes after the event, given predefined fault geometries, allowing emergency first responders and researchers to pinpoint the regions of highest damage. Furthermore, we are also investigating using total displacement waveforms for real-time moment tensor inversions to look at spatiotemporal variations in slip.

From Geodesy to Tectonics: Observing Earthquake Processes from Space (Augustus Love Medal Lecture)

NASA Astrophysics Data System (ADS)

Parsons, Barry

2017-04-01

A suite of powerful satellite-based techniques has been developed over the past two decades allowing us to measure and interpret variations in the deformation around active continental faults occurring in earthquakes, before the earthquakes as strain accumulates, and immediately following them. The techniques include radar interferometry and the measurement of vertical and horizontal surface displacements using very high-resolution (VHR) satellite imagery. They provide near-field measurements of earthquake deformation facilitating the association with the corresponding active faults and their topographic expression. The techniques also enable pre- and post-seismic deformation to be determined and hence allow the response of the fault and surrounding medium to changes in stress to be investigated. The talk illustrates both the techniques and the applications with examples from recent earthquakes. These include the 2013 Balochistan earthquake, a predominantly strike-slip event, that occurred on the arcuate Hoshab fault in the eastern Makran linking an area of mainly left-lateral shear in the east to one of shortening in the west. The difficulty of reconciling predominantly strike-slip motion with this shortening has led to a wide range of unconventional kinematic and dynamic models. Using pre-and post-seismic VHR satellite imagery, we are able to determine a 3-dimensional deformation field for the earthquake; Sentinel-1 interferometry shows an increase in the rate of creep on a creeping section bounding the northern end of the rupture in response to the earthquake. In addition, we will look at the 1978 Tabas earthquake for which no measurements of deformation were possible at the time. By combining pre-seismic 'spy' satellite images with modern imagery, and pre-seismic aerial stereo images with post-seismic satellite stereo images, we can determine vertical and horizontal displacements from the earthquake and subsequent post-seismic deformation. These observations

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…

Nucleation speed limit on remote fluid-induced earthquakes.

PubMed

Parsons, Tom; Malagnini, Luca; Akinci, Aybige

2017-08-01

Earthquakes triggered by other remote seismic events are explained as a response to long-traveling seismic waves that temporarily stress the crust. However, delays of hours or days after seismic waves pass through are reported by several studies, which are difficult to reconcile with the transient stresses imparted by seismic waves. We show that these delays are proportional to magnitude and that nucleation times are best fit to a fluid diffusion process if the governing rupture process involves unlocking a magnitude-dependent critical nucleation zone. It is well established that distant earthquakes can strongly affect the pressure and distribution of crustal pore fluids. Earth's crust contains hydraulically isolated, pressurized compartments in which fluids are contained within low-permeability walls. We know that strong shaking induced by seismic waves from large earthquakes can change the permeability of rocks. Thus, the boundary of a pressurized compartment may see its permeability rise. Previously confined, overpressurized pore fluids may then diffuse away, infiltrate faults, decrease their strength, and induce earthquakes. Magnitude-dependent delays and critical nucleation zone conclusions can also be applied to human-induced earthquakes.

Nucleation speed limit on remote fluid induced earthquakes

USGS Publications Warehouse

Parsons, Thomas E.; Akinci, Aybige; Malignini, Luca

2017-01-01

Earthquakes triggered by other remote seismic events are explained as a response to long-traveling seismic waves that temporarily stress the crust. However, delays of hours or days after seismic waves pass through are reported by several studies, which are difficult to reconcile with the transient stresses imparted by seismic waves. We show that these delays are proportional to magnitude and that nucleation times are best fit to a fluid diffusion process if the governing rupture process involves unlocking a magnitude-dependent critical nucleation zone. It is well established that distant earthquakes can strongly affect the pressure and distribution of crustal pore fluids. Earth’s crust contains hydraulically isolated, pressurized compartments in which fluids are contained within low-permeability walls. We know that strong shaking induced by seismic waves from large earthquakes can change the permeability of rocks. Thus, the boundary of a pressurized compartment may see its permeability rise. Previously confined, overpressurized pore fluids may then diffuse away, infiltrate faults, decrease their strength, and induce earthquakes. Magnitude-dependent delays and critical nucleation zone conclusions can also be applied to human-induced earthquakes.

NASA-Produced Maps Help Gauge Italy Earthquake Damage

NASA Image and Video Library

2016-10-05

A NASA-funded program provided valuable information for responders and groups supporting the recovery efforts for the Aug. 24, 2016, magnitude 6.2 earthquake that struck central Italy. The earthquake caused significant loss of life and property damage in the town of Amatrice. To assist in the disaster response efforts, scientists at NASA's Jet Propulsion Laboratory and Caltech, both in Pasadena, California, obtained and used radar imagery of the earthquake's hardest-hit region to discriminate areas of damage from that event. The views indicate the extent of damage caused by the earthquake and subsequent aftershocks in and around Amatrice, based on changes to the ground surface detected by radar. The color variations from yellow to red indicate increasingly more significant ground surface change. The damage maps were created from data obtained before and after the earthquake by satellites belonging to the Italian Space Agency (ASI) and the Japan Aerospace Exploration Agency (JAXA). The radar-derived damage maps compare well with a damage map produced by the European Commission Copernicus Emergency Management Service based upon visual inspection of high-resolution pre-earthquake aerial photographs and post-earthquake satellite optical imagery, and provide broader geographic coverage of the earthquake's impact in the region. The X-band COSMO-SkyMed (CSK) data were provided through a research collaboration with ASI and were acquired on July 3, August 20, and August 28, 2016. The L-band ALOS/PALSAR-2 data were provided by JAXA through its science research program and were acquired on September 9, 2015, January 27, 2016, and August 24, 2016. The radar data were processed by the Advanced Rapid Imaging and Analysis (ARIA) team at JPL and Caltech. ARIA is a NASA-funded project that is building an automated system for demonstrating the ability to rapidly and reliably provide GPS and satellite data to support the local, national and international hazard monitoring and

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

Response and recovery lessons from the 2010-2011 earthquake sequence in Canterbury, New Zealand

USGS Publications Warehouse

Pierepiekarz, Mark; Johnston, David; Berryman, Kelvin; Hare, John; Gomberg, Joan S.; Williams, Robert A.; Weaver, Craig S.

2014-01-01

The impacts and opportunities that result when low-probability moderate earthquakes strike an urban area similar to many throughout the US were vividly conveyed in a one-day workshop in which social and Earth scientists, public officials, engineers, and an emergency manager shared their experiences of the earthquake sequence that struck the city of Christchurch and surrounding Canterbury region of New Zealand in 2010-2011. Without question, the earthquake sequence has had unprecedented impacts in all spheres on New Zealand society, locally to nationally--10% of the country's population was directly impacted and losses total 8-10% of their GDP. The following paragraphs present a few lessons from Christchurch.

Analysis of the Earthquake Impact towards water-based fire extinguishing system

NASA Astrophysics Data System (ADS)

Lee, J.; Hur, M.; Lee, K.

2015-09-01

Recently, extinguishing system installed in the building when the earthquake occurred at a separate performance requirements. Before the building collapsed during the earthquake, as a function to maintain a fire extinguishing. In particular, the automatic sprinkler fire extinguishing equipment, such as after a massive earthquake without damage to piping also must maintain confidentiality. In this study, an experiment installed in the building during the earthquake, the water-based fire extinguishing saw grasp the impact of the pipe. Experimental structures for water-based fire extinguishing seismic construction step by step, and then applied to the seismic experiment, the building appears in the extinguishing of the earthquake response of the pipe was measured. Construction of acceleration caused by vibration being added to the size and the size of the displacement is measured and compared with the data response of the pipe from the table, thereby extinguishing water piping need to enhance the seismic analysis. Define the seismic design category (SDC) for the four groups in the building structure with seismic criteria (KBC2009) designed according to the importance of the group and earthquake seismic intensity. The event of a real earthquake seismic analysis of Category A and Category B for the seismic design of buildings, the current fire-fighting facilities could have also determined that the seismic performance. In the case of seismic design categories C and D are installed in buildings to preserve the function of extinguishing the required level of seismic retrofit design is determined.

ELER software - a new tool for urban earthquake loss assessment

NASA Astrophysics Data System (ADS)

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

2010-12-01

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

SENSITIVITY OF STRUCTURAL RESPONSE TO GROUND MOTION SOURCE AND SITE PARAMETERS.

USGS Publications Warehouse

Safak, Erdal; Brebbia, C.A.; Cakmak, A.S.; Abdel Ghaffar, A.M.

1985-01-01

Designing structures to withstand earthquakes requires an accurate estimation of the expected ground motion. While engineers use the peak ground acceleration (PGA) to model the strong ground motion, seismologists use physical characteristics of the source and the rupture mechanism, such as fault length, stress drop, shear wave velocity, seismic moment, distance, and attenuation. This study presents a method for calculating response spectra from seismological models using random vibration theory. It then investigates the effect of various source and site parameters on peak response. Calculations are based on a nonstationary stochastic ground motion model, which can incorporate all the parameters both in frequency and time domains. The estimation of the peak response accounts for the effects of the non-stationarity, bandwidth and peak correlations of the response.

Using remote sensing to predict earthquake impacts

NASA Astrophysics Data System (ADS)

Fylaktos, Asimakis; Yfantidou, Anastasia

2017-09-01

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

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

PubMed

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

2016-01-08

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

Very low frequency earthquakes along the Ryukyu subduction zone

NASA Astrophysics Data System (ADS)

Ando, Masataka; Tu, Yoko; Kumagai, Hiroyuki; Yamanaka, Yoshiko; Lin, Cheng-Horng

2012-02-01

A total of 1314 very low frequency earthquakes (VLFEs) were identified along the Ryukyu trench from seismograms recorded at broadband networks in Japan (F-net) and Taiwan (BATS) in 2007. The spectra of typical VLFEs have peak frequencies between 0.02 to 0.1 Hz. Among those, waveforms from 120 VLFEs were inverted to obtain their centoroid moment tensor (CMT) solutions and locations using an examination grid to minimize a residual between the observed and synthetic waveforms within an area of 11° × 14° in latitude and longitude and at depths of 0 to 60 km. Most of the VLFEs occur on shallow thrust faults that are distributed along the Ryukyu trench, which are similar to those earthquakes found in Honshu and Hokkaido, Japan. The locations and mechanisms of VLFEs may be indicative of coupled regions within the accretionary prism or at the plate interface; this study highlights the need for further investigation of the Ryukyu trench to identify coupled regions within it.

Did the Zipingpu Reservoir trigger the 2008 Wenchuan earthquake?

USGS Publications Warehouse

Ge, S.; Liu, M.; Lu, N.; Godt, J.W.; Luo, G.

2009-01-01

The devastating May 2008 Wenchuan earthquake (Mw 7.9) resulted from thrust of the Tibet Plateau on the Longmen Shan fault zone, a consequence of the Indo-Asian continental collision. Many have speculated on the role played by the Zipingpu Reservoir, impounded in 2005 near the epicenter, in triggering the earthquake. This study evaluates the stress changes in response to the impoundment of the Zipingpu Reservoir and assesses their impact on the Wenchuan earthquake. We show that the impoundment could have changed the Coulomb stress by -0.01 to 0.05 MPa at locations and depth consistent with reported hypocenter positions. This level of stress change has been shown to be significant in triggering earthquakes on critically stressed faults. Because the loading rate on the Longmen Shan fault is <0.005 MPa/yr, we thus suggest that the Zipingpu Reservoir potentially hastened the occurrence of the Wenchuan earthquake by tens to hundreds of years. Copyright 2009 by the American Geophysical Union.

Hotspots, Lifelines, and the Safrr Haywired Earthquake Sequence

NASA Astrophysics Data System (ADS)

Ratliff, J. L.; Porter, K.

2014-12-01

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

Stability assessment of structures under earthquake hazard through GRID technology

NASA Astrophysics Data System (ADS)

Prieto Castrillo, F.; Boton Fernandez, M.

2009-04-01

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

Modelling low-frequency volcanic earthquakes in a viscoelastic medium with topography

NASA Astrophysics Data System (ADS)

Jousset, P.; Neuberg, J.

2003-04-01

Magma properties are fundamental to explain the volcanic eruption style as well as the generation and propagation of seismic waves. This study focusses on rheological magma properties and their impact on low-frequency volcanic earthquakes. We investigate the effects of anelasticity and topography on the amplitudes and spectra of synthetic low-frequency earthquakes. Using a 2D finite difference scheme, we model the propagation of seismic energy initiated in a fluid-filled conduit embedded in a 2D homogeneous viscoelastic medium with topography. Topography is introduced by using a mapping procedure that stretches the computational rectangular grid into a grid which follows the topography. We model intrinsic attenuation by linear viscoelastic theory and we show that volcanic media can be approximated by a standard linear solid for seismic frequencies (i.e., above 2 Hz). Results demonstrate that attenuation modifies both amplitude and dispersive characteristics of low-frequency earthquakes. Low-frequency events are dispersive by nature; however, if attenuation is introduced, their dispersion characteristics will be altered. The topography modifies the amplitudes, depending on the position of seismographs at the surface. This study shows that we need to take into account attenuation and topography to interpret correctly observed low-frequency volcanic earthquakes. It also suggests that the rheological properties of magmas may be constrained by the analysis of low-frequency seismograms.

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

USGS Publications Warehouse

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

2008-01-01

The question is not if but when southern California will be hit by a major earthquake - one so damaging that it will permanently change lives and livelihoods in the region. How severe the changes will be depends on the actions that individuals, schools, businesses, organizations, communities, and governments take to get ready. To help prepare for this event, scientists of the U.S. Geological Survey (USGS) have changed the way that earthquake scenarios are done, uniting a multidisciplinary team that spans an unprecedented number of specialties. The team includes the California Geological Survey, Southern California Earthquake Center, and nearly 200 other partners in government, academia, emergency response, and industry, working to understand the long-term impacts of an enormous earthquake on the complicated social and economic interactions that sustain southern California society. This project, the ShakeOut Scenario, has applied the best current scientific understanding to identify what can be done now to avoid an earthquake catastrophe. More information on the science behind this project will be available in The ShakeOut Scenario (USGS Open-File Report 2008-1150; http://pubs.usgs.gov/of/2008/1150/). The 'what if?' earthquake modeled in the ShakeOut Scenario is a magnitude 7.8 on the southern San Andreas Fault. Geologists selected the details of this hypothetical earthquake by considering the amount of stored strain on that part of the fault with the greatest risk of imminent rupture. From this, seismologists and computer scientists modeled the ground shaking that would occur in this earthquake. Engineers and other professionals used the shaking to produce a realistic picture of this earthquake's damage to buildings, roads, pipelines, and other infrastructure. From these damages, social scientists projected casualties, emergency response, and the impact of the scenario earthquake on southern California's economy and society. The earthquake, its damages, and

Characteristics of broadband slow earthquakes explained by a Brownian model

NASA Astrophysics Data System (ADS)

Ide, S.; Takeo, A.

2017-12-01

Brownian slow earthquake (BSE) model (Ide, 2008; 2010) is a stochastic model for the temporal change of seismic moment release by slow earthquakes, which can be considered as a broadband phenomena including tectonic tremors, low frequency earthquakes, and very low frequency (VLF) earthquakes in the seismological frequency range, and slow slip events in geodetic range. Although the concept of broadband slow earthquake may not have been widely accepted, most of recent observations are consistent with this concept. Then, we review the characteristics of slow earthquakes and how they are explained by BSE model. In BSE model, the characteristic size of slow earthquake source is represented by a random variable, changed by a Gaussian fluctuation added at every time step. The model also includes a time constant, which divides the model behavior into short- and long-time regimes. In nature, the time constant corresponds to the spatial limit of tremor/SSE zone. In the long-time regime, the seismic moment rate is constant, which explains the moment-duration scaling law (Ide et al., 2007). For a shorter duration, the moment rate increases with size, as often observed for VLF earthquakes (Ide et al., 2008). The ratio between seismic energy and seismic moment is constant, as shown in Japan, Cascadia, and Mexico (Maury et al., 2017). The moment rate spectrum has a section of -1 slope, limited by two frequencies corresponding to the above time constant and the time increment of the stochastic process. Such broadband spectra have been observed for slow earthquakes near the trench axis (Kaneko et al., 2017). This spectrum also explains why we can obtain VLF signals by stacking broadband seismograms relative to tremor occurrence (e.g., Takeo et al., 2010; Ide and Yabe, 2014). The fluctuation in BSE model can be non-Gaussian, as far as the variance is finite, as supported by the central limit theorem. Recent observations suggest that tremors and LFEs are spatially characteristic

Is Your Class a Natural Disaster? It can be... The Real Time Earthquake Education (RTEE) System

NASA Astrophysics Data System (ADS)

Whitlock, J. S.; Furlong, K.

2003-12-01

In cooperation with the U.S. Geological Survey (USGS) and its National Earthquake Information Center (NEIC) in Golden, Colorado, we have implemented an autonomous version of the NEIC's real-time earthquake database management and earthquake alert system (Earthworm). This is the same system used professionally by the USGS in its earthquake response operations. Utilizing this system, Penn State University students participating in natural hazard classes receive real-time alerts of worldwide earthquake events on cell phones distributed to the class. The students are then responsible for reacting to actual earthquake events, in real-time, with the same data (or lack thereof) as earthquake professionals. The project was first implemented in Spring 2002, and although it had an initial high intrigue and "coolness" factor, the interest of the students waned with time. Through student feedback, we observed that scientific data presented on its own without an educational context does not foster student learning. In order to maximize the impact of real-time data and the accompanying e-media, the students need to become personally involved. Therefore, in collaboration with the Incorporated Research Institutes of Seismology (IRIS), we have begun to develop an online infrastructure that will help teachers and faculty effectively use real-time earthquake information. The Real-Time Earthquake Education (RTEE) website promotes student learning by integrating inquiry-based education modules with real-time earthquake data. The first module guides the students through an exploration of real-time and historic earthquake datasets to model the most important criteria for determining the potential impact of an earthquake. Having provided the students with content knowledge in the first module, the second module presents a more authentic, open-ended educational experience by setting up an earthquake role-play situation. Through the Earthworm system, we have the ability to "set off

Strong ground motion in the Kathmandu Valley during the 2015 Gorkha, Nepal, earthquake

NASA Astrophysics Data System (ADS)

Takai, Nobuo; Shigefuji, Michiko; Rajaure, Sudhir; Bijukchhen, Subeg; Ichiyanagi, Masayoshi; Dhital, Megh Raj; Sasatani, Tsutomu

2016-01-01

On 25 April 2015, a large earthquake of Mw 7.8 occurred along the Main Himalayan Thrust fault in central Nepal. It was caused by a collision of the Indian Plate beneath the Eurasian Plate. The epicenter was near the Gorkha region, 80 km northwest of Kathmandu, and the rupture propagated toward east from the epicentral region passing through the sediment-filled Kathmandu Valley. This event resulted in over 8000 fatalities, mostly in Kathmandu and the adjacent districts. We succeeded in observing strong ground motions at our four observation sites (one rock site and three sedimentary sites) in the Kathmandu Valley during this devastating earthquake. While the observed peak ground acceleration values were smaller than the predicted ones that were derived from the use of a ground motion prediction equation, the observed peak ground velocity values were slightly larger than the predicted ones. The ground velocities observed at the rock site (KTP) showed a simple velocity pulse, resulting in monotonic-step displacements associated with the permanent tectonic offset. The vertical ground velocities observed at the sedimentary sites had the same pulse motions that were observed at the rock site. In contrast, the horizontal ground velocities as well as accelerations observed at three sedimentary sites showed long duration with conspicuous long-period oscillations, due to the valley response. The horizontal valley response was characterized by large amplification (about 10) and prolonged oscillations. However, the predominant period and envelope shape of their oscillations differed from site to site, indicating a complicated basin structure. Finally, on the basis of the velocity response spectra, we show that the horizontal long-period oscillations on the sedimentary sites had enough destructive power to damage high-rise buildings with natural periods of 3 to 5 s.

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.

Crustal earthquake triggering by pre-historic great earthquakes on subduction zone thrusts

USGS Publications Warehouse

Sherrod, Brian; Gomberg, Joan

2014-01-01

Triggering of earthquakes on upper plate faults during and shortly after recent great (M>8.0) subduction thrust earthquakes raises concerns about earthquake triggering following Cascadia subduction zone earthquakes. Of particular regard to Cascadia was the previously noted, but only qualitatively identified, clustering of M>~6.5 crustal earthquakes in the Puget Sound region between about 1200–900 cal yr B.P. and the possibility that this was triggered by a great Cascadia thrust subduction thrust earthquake, and therefore portends future such clusters. We confirm quantitatively the extraordinary nature of the Puget Sound region crustal earthquake clustering between 1200–900 cal yr B.P., at least over the last 16,000. We conclude that this cluster was not triggered by the penultimate, and possibly full-margin, great Cascadia subduction thrust earthquake. However, we also show that the paleoseismic record for Cascadia is consistent with conclusions of our companion study of the global modern record outside Cascadia, that M>8.6 subduction thrust events have a high probability of triggering at least one or more M>~6.5 crustal earthquakes.

Earthquake source parameters determined by the SAFOD Pilot Hole seismic array

USGS Publications Warehouse

Imanishi, K.; Ellsworth, W.L.; Prejean, S.G.

2004-01-01

We estimate the source parameters of #3 microearthquakes by jointly analyzing seismograms recorded by the 32-level, 3-component seismic array installed in the SAFOD Pilot Hole. We applied an inversion procedure to estimate spectral parameters for the omega-square model (spectral level and corner frequency) and Q to displacement amplitude spectra. Because we expect spectral parameters and Q to vary slowly with depth in the well, we impose a smoothness constraint on those parameters as a function of depth using a linear first-differenfee operator. This method correctly resolves corner frequency and Q, which leads to a more accurate estimation of source parameters than can be obtained from single sensors. The stress drop of one example of the SAFOD target repeating earthquake falls in the range of typical tectonic earthquakes. Copyright 2004 by the American Geophysical Union.

Refinements on the inferred causative faults of the great 2012 Indian Ocean earthquakes

NASA Astrophysics Data System (ADS)

Revathy, P. M.; Rajendran, K.

2014-12-01

As the largest known intra-plate strike-slip events, the pair of 2012 earthquakes in the Wharton Basin is a rarity. Separated in time by 2 hours these events rouse interest also because of their short inter-event duration, complex rupture mechanism, and spatial-temporal proximity to the great 2004 Sumatra plate boundary earthquake. Reactivation of fossil ridge-transform pairs is a favoured mechanism for large oceanic plate earthquakes and their inherent geometry triggers earthquakes on conjugate fault systems, as observed previously in the Wharton Basin. The current debate is whether the ruptures occurred on the WNW-ESE paleo ridges or the NNE-SSW paleo transforms. Back-projection models give a complex rupture pattern that favours the WNW-ESE fault [1]. However, the static stress changes due to the 2004 Sumatra earthquake and 2005 Nias earthquake favour the N15°E fault [2]. We use the Teleseismic Body-Wave Inversion Program [3] and waveform data from Global Seismic Network, to obtain the best fit solutions using P and S-wave synthetic modelling. The preliminary P-wave analysis of both earthquakes gives source parameters that are consistent with the Harvard CMT solutions. The obtained slip distribution complies with the NNE-SSW transforms. Both these earthquakes triggered small tsunamis which appear as two distinctive pulses on 13 Indian Ocean tide gauges and buoys. Frequency spectra of the tsunami recordings from various azimuths provide additional constraint for the choice of the causative faults. References: [1] Yue, H., T. Lay, and K. D. Koper (2012), En echelon and orthogonal fault ruptures of the 11 April 2012 great intraplate earthquakes, Nature, 490, 245-249, doi:10.1038/nature11492 [2] Delescluse, M., N. Chamot-Rooke, R. Cattin, L. Fleitout, O. Trubienko and C. Vigny April 2012 intra-oceanic seismicity off Sumatra boosted by the Banda-Aceh megathrust, Nature, 490(2012), pp. 240-244, doi:10.1038/nature11520 [3] M. Kikuchi and H. Kanamori, Note on

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

USGS Publications Warehouse

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

2001-01-01

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

Impact-based earthquake alerts with the U.S. Geological Survey's PAGER system: what's next?

USGS Publications Warehouse

Wald, D.J.; Jaiswal, K.S.; Marano, K.D.; Garcia, D.; So, E.; Hearne, M.

2012-01-01

In September 2010, the USGS began publicly releasing earthquake alerts for significant earthquakes around the globe based on estimates of potential casualties and economic losses with its Prompt Assessment of Global Earthquakes for Response (PAGER) system. These estimates significantly enhanced the utility of the USGS PAGER system which had been, since 2006, providing estimated population exposures to specific shaking intensities. Quantifying earthquake impacts and communicating estimated losses (and their uncertainties) to the public, the media, humanitarian, and response communities required a new protocol—necessitating the development of an Earthquake Impact Scale—described herein and now deployed with the PAGER system. After two years of PAGER-based impact alerting, we now review operations, hazard calculations, loss models, alerting protocols, and our success rate for recent (2010-2011) events. This review prompts analyses of the strengths, limitations, opportunities, and pressures, allowing clearer definition of future research and development priorities for the PAGER system.

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

Large-Scale Earthquake Countermeasures Act and the Earthquake Prediction Council in Japan

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

Rikitake, T.

1979-08-07

The Large-Scale Earthquake Countermeasures Act was enacted in Japan in December 1978. This act aims at mitigating earthquake hazards by designating an area to be an area under intensified measures against earthquake disaster, such designation being based on long-term earthquake prediction information, and by issuing an earthquake warnings statement based on imminent prediction information, when possible. In an emergency case as defined by the law, the prime minister will be empowered to take various actions which cannot be taken at ordinary times. For instance, he may ask the Self-Defense Force to come into the earthquake-threatened area before the earthquake occurrence.more » A Prediction Council has been formed in order to evaluate premonitory effects that might be observed over the Tokai area, which was designated an area under intensified measures against earthquake disaster some time in June 1979. An extremely dense observation network has been constructed over the area.« less

Analysis of Earthquake Recordings Obtained from the Seafloor Earthquake Measurement System (SEMS) Instruments Deployed off the Coast of Southern California

USGS Publications Warehouse

Boore, D.M.; Smith, C.E.

1999-01-01

For more than 20 years, a program has been underway to obtain records of earthquake shaking on the seafloor at sites offshore of southern California, near oil platforms. The primary goal of the program is to obtain data that can help determine if ground motions at offshore sites are significantly different than those at onshore sites; if so, caution may be necessary in using onshore motions as the basis for the seismic design of oil platforms. We analyze data from eight earthquakes recorded at six offshore sites; these are the most important data recorded on these stations to date. Seven of the earthquakes were recorded at only one offshore station; the eighth event was recorded at two sites. The earthquakes range in magnitude from 4.7 to 6.1. Because of the scarcity of multiple recordings from any one event, most of the analysis is based on the ratio of spectra from vertical and horizontal components of motion. The results clearly show that the offshore motions have very low vertical motions compared to those from an average onshore site, particularly at short periods. Theoretical calculations find that the water layer has little effect on the horizontal components of motion but that it produces a strong spectral null on the vertical component at the resonant frequency of P waves in the water layer. The vertical-to-horizontal ratios for a few selected onshore sites underlain by relatively low shear-wave velocities are similar to the ratios from offshore sites for frequencies less than about one-half the water layer P-wave resonant frequency, suggesting that the shear-wave velocities beneath a site are more important than the water layer in determining the character of the ground motions at lower frequencies.

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.

Inducing in situ, nonlinear soil response applying an active source

USGS Publications Warehouse

Johnson, P.A.; Bodin, P.; Gomberg, J.; Pearce, F.; Lawrence, Z.; Menq, F.-Y.

2009-01-01

[1] It is well known that soil sites have a profound effect on ground motion during large earthquakes. The complex structure of soil deposits and the highly nonlinear constitutive behavior of soils largely control nonlinear site response at soil sites. Measurements of nonlinear soil response under natural conditions are critical to advancing our understanding of soil behavior during earthquakes. Many factors limit the use of earthquake observations to estimate nonlinear site response such that quantitative characterization of nonlinear behavior relies almost exclusively on laboratory experiments and modeling of wave propagation. Here we introduce a new method for in situ characterization of the nonlinear behavior of a natural soil formation using measurements obtained immediately adjacent to a large vibrator source. To our knowledge, we are the first group to propose and test such an approach. Employing a large, surface vibrator as a source, we measure the nonlinear behavior of the soil by incrementally increasing the source amplitude over a range of frequencies and monitoring changes in the output spectra. We apply a homodyne algorithm for measuring spectral amplitudes, which provides robust signal-to-noise ratios at the frequencies of interest. Spectral ratios are computed between the receivers and the source as well as receiver pairs located in an array adjacent to the source, providing the means to separate source and near-source nonlinearity from pervasive nonlinearity in the soil column. We find clear evidence of nonlinearity in significant decreases in the frequency of peak spectral ratios, corresponding to material softening with amplitude, observed across the array as the source amplitude is increased. The observed peak shifts are consistent with laboratory measurements of soil nonlinearity. Our results provide constraints for future numerical modeling studies of strong ground motion during earthquakes.

Rapid Large Earthquake and Run-up Characterization in Quasi Real Time

NASA Astrophysics Data System (ADS)

Bravo, F. J.; Riquelme, S.; Koch, P.; Cararo, S.

2017-12-01

Several test in quasi real time have been conducted by the rapid response group at CSN (National Seismological Center) to characterize earthquakes in Real Time. These methods are known for its robustness and realibility to create Finite Fault Models. The W-phase FFM Inversion, The Wavelet Domain FFM and The Body Wave and FFM have been implemented in real time at CSN, all these algorithms are running automatically and triggered by the W-phase Point Source Inversion. Dimensions (Large and Width ) are predefined by adopting scaling laws for earthquakes in subduction zones. We tested the last four major earthquakes occurred in Chile using this scheme: The 2010 Mw 8.8 Maule Earthquake, The 2014 Mw 8.2 Iquique Earthquake, The 2015 Mw 8.3 Illapel Earthquake and The 7.6 Melinka Earthquake. We obtain many solutions as time elapses, for each one of those we calculate the run-up using an analytical formula. Our results are in agreements with some FFM already accepted by the sicentific comunnity aswell as run-up observations in the field.