Ground Motion Attenuation Relations Research Articles

Site classification methodology using support vector machine: A study

The site effect is a crucial factor when analyzing seismic risk and establishing ground motion attenuation relationships. A number of countries have introduced building site classification into earthquake-resistant design codes to account for local site effects on ground motion. However, most of the site classification indicators rely on drilling data, which is often expensive and requires considerable manpower. As a result, the less detailed drilling data may lead to an undetermined site category of numerous stations. In this study, a Support Vector Machine (SVM) algorithm-based site classification model was trained to address this issue using strong ground motion data and site data from KiK-net and K-net. The classification model used the average HVSR curve of the labeled site and the combined inputs including frequency, peak, “prominence” and “sharpness” extracted from the curve. The SVM classification model has an accuracy of 76.12% on the test set, with recall rates of 82.69%, 75%, and 63.64% for sites I, II, and III, respectively. The precision rates are 75.44%, 73.77%, and 87.50%, respectively, with F1 scores of 78.90%, 74.38%, and 73.68%. For sites without significant peaks in the HVSR curve, the HVSR curve value was used as the characteristic parameter (input), and the SVM-based site classification model was also trained. The accuracy of class I and II is 75.86%. The results of this study show higher recall and accuracy rates than those obtained using the spectral ratio curve matching method (Wen et al., 2015) and GRNN method (Ji et al., 2021), indicating a better classification performance. Finally, the generalization ability of the model was verified using some basic stations in Xinjiang deployed by the “National Seismic Intensity Rapid Reporting and Early Warning Project”. The SVM-based site classification model that employs strong motion data can provide more reliable classification results for sites without detailed borehole information, and the site classification results can serve as a reference for probing ground motion attenuation relationships, ground motion simulation, and seismic fortification considering the site effect.

Numerical Modeling of Air-Blast Suppression as a Function of Explosive-Charge Burial Depth

Abstract As a chemical explosion is buried, the mechanism for acoustic wave generation transitions from fully gas-generated at the surface to completely spall-induced at full containment depth. The fully gas-generated and completely spall-induced signals in the acoustic waveform are well described; however, the transition between these two end-members eludes numerical modeling because of the complex phenomena that are involved. The phenomena of crater formation and explosive cloud evolution are simulated using an Eulerian hydrocode that incorporates geomaterials with strength and porosity. Having accurately modeled these phenomena, we can confidently predict the propagation and relative strength of the gas-generated and spall-induced pulses in the recorded acoustic waveform. The numerical predictions agree with observations from the historical Stagecoach experiment as well as modern recordings from the Source Physics Experiment. In particular, the peak pressure p generated by an explosion is initially due to the gas-generated mechanism and decays with scaled depth of burial ds (depth d scaled by the cube-root of explosive yield w1/3) as exp(−ds) but then transitions near a scaled depth of 6 m/ton1/3 to the spall-generated mechanism in which the decay is ds−7/4. This decay form is related to the strong ground-motion attenuation relationship that affects spall strength. These results can improve seismoacoustic inverse models for the explosive source that need to account for the gas-generated and spall-induced signals and their effect on peak pressures and other acoustic signal features.

Preliminary Evaluation of Crustal Medium Parameters in Western China

The establishment of attenuation relation of ground motion is always an important research content in engineering earthquake field. In seismology-based ground motion attenuation relationship and ground motion simulation using the stochastic method, regional parameters are necessary. These parameters involve stress drop Δσ, two segmentation points R1 and R2 of the geometric spreading item, Q0 and η of the inelastic attenuation item and the near-surface high-frequency decay parameter κ0, which reflect the regional crustal medium and site characteristics and have little relation with the earthquake size. In this paper, we take Sichuan, Yunnan and Xinjiang regions in western China as examples and we inverse the parameters for each region by micro-genetic algorithm. The inversion ranges of crustal media parameters in the three regions were determined respectively. Finally, we get the inversion results of every parameters and find that the parameters of the three regions have a great difference.

Regional Finite-Fault Source Model for Development of Ground Motion Attenuation Relationship in Sichuan, China

The attenuation relationship of ground motion based on seismology has always been a front subject of engineering earthquake. Among them, the regional finite-fault source model is very important. In view of this point, the general characteristics of regional seism-tectonics, including the dip and depth of the fault plane, are emphasized. According to the statistics of regional seism-tectonics and focal mechanisms in Sichuan, China, and the sensitivity of estimated peak ground acceleration (PGA) attenuation is analyzed, and the dip angle is taken as an average of 70°. Based the statistics of the upper crustal structure and the focal depth of regional earthquakes, the bottom boundary of the sedimentary cover can be used as the upper limit for estimating the depth of upper-edge. The analysis shows that this value is sensitive to PGA. Based on the analysis of geometric relations, the corresponding calculation formula is used, and a set of concepts and steps for building the regional finite-fault source model is proposed. The estimation of source parameters takes into account the uncertainty, the geometric relationship among parameters and the total energy conservation. Meanwhile, a set of reasonable models is developed, which lay a foundation for the further study of regional ground motion attenuation based on seismology.

EARTHQUAKE HAZARD ASSESSMENT STUDIES IN THE STATE OF KUWAIT

This study addresses the first and most important step in measuring the level of seismic hazard in Kuwait. As a result of development, there has been a rise in urban growth leading to the establishment of massive structures and skyscrapers in Kuwait. Therefore, there is demand for seismic risk assessment and the creation of a single seismic code for the country. Consequently, the historical and instrumental data were compiled into seismic catalogs of Kuwait and the active Zagros Seismic Belt. The magnitudes have been unified, extraneous earthquakes removed, and the catalogs' entirety has been taken into account. A seismotectonic model for the Kuwait region has been built to minimize the epistemic uncertainties. The model functions by combining seismicity patterns and structural geological conditions. The probability of experiencing the largest predicted earthquake emerging from every seismic source was calculated together with the parameters set for recurrence. Furthermore, the creation of hazard maps required a suitable ground motion attenuation relation within a logic tree design. Considering recurrence intervals of 100, 475, 975, and 2475 years (corresponding to 39.3 percent, 10%, 5%, and 2%, accordingly, the likelihood of exceedance in 50 years), a probability-based technique is utilized in the study to construct hazard maps at the following 0, 0.1, 0.2, 0.5, 1, 2, 3 and 4 seconds. The maps of scaling hazard areas were created using a 0.2 ° x 0.2 ° spacing grid throughout Kuwait. The five regions of Kuwait (Kuwait City, Salmiya Area, Sabriya Area, Managish Area, and Um Gudair Area) have all implemented a consistent spectrum of hazards. The findings of this study plus the vulnerability index serve the essential features required to calculate Kuwait's seismic risk.

Assessment of seismic hazards in Yemen

The seismic hazard analyses for Yemen have attracted the attention of researchers during the last two decades. However, the studies are limited and mainly use deterministic or approximate conventional probabilistic approaches. The conclusions drawn from these studies do not fit with current seismic design codes (International Building Code). This article presented the method and findings of a probabilistic seismic hazard assessment for Yemen in accordance with current seismic design building regulations. All the data sources, available nationally and internationally, were utilized in compiling earthquake database by covering the recent records and the seismic activity maps of the study region. The study area was regionalized to 11 seismotectonic area sources on the basis of the seismicity maps and available tectonic maps. On the analytical side, the earthquake recurrence analysis was evaluated for each source, and logic tree concept was used to model the seismic sources that may have significant effect on seismic hazard evaluation of Yemen as a combination of area and line sources. A probabilistic forecasting model was formulated, appropriate ground motion attenuation relationships were used, and seismic hazard contour maps were developed for the entire Yemen area. The maps present dense contours of peak ground accelerations and short and long period spectral accelerations for different return periods. The highest predicted seismic hazard is found in Dhamar City. This study provides basic and essential requirements that will be valuable in developing advanced seismic design criteria for Yemen.

Multisource Ground Motion Attenuation Relationship Model for the Vertical Component of the Wenchuan Earthquake on May 12, 2008

In order to extend the multisource model to vertical ground motion, we fit the vertical ground motion attenuation relationship of the Wenchuan earthquake. Different from traditional attenuation relationship forms, we propose a simplified ground motion attenuation function including site effect via a flag related to VS30. The regression results show that it has site effect on the vertical ground motion of the Wenchuan earthquake and gradually weakens with the increase in periods. According to residuals analysis, the hanging-wall effect on vertical ground motion is strong for the Wenchuan earthquake, especially in short periods. The result analysis indicates that the shape of the vertical response spectrum based on regression is different from that of the horizontal component and complies with the recommended design vertical response spectrum of FEMA P-1050. V/H (vertical-to-horizontal ratios), as a main way to estimate vertical ground motion, cannot be simply fixed as 2/3. Therefore, site location, site condition, and frequency spectrum have to be considered comprehensively. The regression accuracy of the vertical ground motion of the multisource model is slightly higher than that of the point-source model and lower than that of the finite fault source model. It is expected that this model will serve as an alternative for source-to-site distance when multiple asperities are to be modeled in the absence of the detail fault model to get a general scenario of the future ground motions.

Assessment of Seismic Hazard in Yemen

The seismic hazard analyses for Yemen has attracted the attention of researchers during the last two decades. However, the studies are limited and mainly employ deterministic or approximate conventional probabilistic approaches. Furthermore, the conclusions drawn from these researches do not fit with current seismic design codes. This article describes the method and findings of a probabilistic seismic hazard assessment for Yemen, in accordance with current seismic design building regulations. The study utilized all the data sources, available nationally and internationally, in compiling earthquake database by covering the recent records and the seismic activity maps of the study region and regionalized the study area to eleven seismotectonic area sources based on the seismicity maps and available tectonic maps. On the analytical side, the study evaluated the earthquake recurrence analysis for each source, employed the logic tree concept to model the seismic sources, that may have significant effect on seismic hazard evaluation of Yemen, as a combination of area and line sources. Moreover, the study formulated a probabilistic forecasting model, used appropriate ground motion attenuation relationships, and developed seismic hazard contour maps for the entire Yemen area. The maps present dense contours of both peak ground accelerations, and short as well as long period spectral accelerations for different return periods. The highest predicted seismic hazard is found in Dhamar city. This study furnishes basic and essential requirements that will be of great help in developing advanced seismic design criteria for Yemen.

Seismic hazard maps of Peshawar District for various return periods

Abstract. Probabilistic seismic hazard analysis of Peshawar District has been performed for a grid size of 0.01∘. The seismic sources for the target location are defined as the area polygon with uniform seismicity. The earthquake catalogue was developed based on the earthquake data obtained from different worldwide seismological networks and historical records. The earthquake events obtained at different magnitude scales were converted into moment magnitude using indigenous catalogue-specific regression relationships. The homogenized catalogue was subdivided into shallow crustal and deep-subduction-zone earthquake events. The seismic source parameters were obtained using the bounded Gutenberg–Richter recurrence law. Seismic hazard maps were prepared for peak horizontal acceleration at bedrock level using different ground motion attenuation relationships. The study revealed the selection of an appropriate ground motion prediction equation is crucial for defining the seismic hazard of Peshawar District. The inclusion of deep subduction earthquakes does not add significantly to the seismic hazard for design base ground motions. The seismic hazard map developed for shallow crustal earthquakes, including also the epistemic uncertainty, was in close agreement with the map given in the Building Code of Pakistan Seismic Provisions (2007) for a return period of 475 years on bedrock. The seismic hazard maps for other return periods i.e., 50, 100, 250, 475 and 2500 years, are also presented.

Discussion on the Site Effect Coefficient and Topographic Effect Coefficient of Ground Motion Peak Acceleration and Its Relationship

By summarizing the research results of the site effect coefficient and topographic effect coefficient of ground motion peak acceleration, we analyzed the ground motion site effect and topographic effect and concluded that the relationship between site effect and topographic effect was wane and wax and gradually transition. The amplification factor of the peak acceleration of the surface can be calculated by multiplying the site effect coefficient and the topographic effect coefficient. The article proposes to study the site effect coefficient and the topographic effect coefficient in two ways and obtain the function expression. In the introduction of Vs30, the calculation method of the limits of two effect of Vs30 as the parameter is also proposed. Through the above methods, accurate ground motion peak acceleration can be obtained, which provides support for seismic design, ground motion attenuation relationship research and seismic geological disaster prevention.

Seismic loss estimation tool as rapid survey for prioritizing buildings for disaster preparedness: case study to hospital buildings

Hospital buildings must be fully operational after the earthquake to protect the lives of patients as well as to provide emergency care and medical treatment to the victims. Prioritization and justification of founding of such hospital buildings is an effective step under earthquake disaster preparedness. In this work, a seismic loss estimation tool (SRAI.SA) is used considering hazard on regional ground motion attenuation relation at micro-seismic level. The proposed tool is used to prioritize different hospital buildings of a metropolitan city of India during walk down survey. Rapid visual screening given by FEMA and structural vulnerability index by NORSAR questionnaires are also used for prioritization based on scoring during same walk down survey. It is found that prioritization graphs by all the three methods are almost at parity. Since rapid visual screening and structural vulnerability index methods are qualitative method and need experience and judgment of the expert, the loss estimation tool ensures effective tools for prioritizing buildings through which decision makers can be guided in prioritizing buildings and identifying buildings that require immediate attention for detailed investigation.

Development of a Web-GIS based Decision Support System for earthquake warning service in Vietnam

This paper describes the development of a Decision support system (DSS) for earthquake warning service in Vietnam using Web GIS technology. The system consists of two main components: (1) an on-line database of earthquakes recorded from the national seismic network of Vietnam, and (2) a set of tools for rapid seismic hazard assessment. Using an online earthquake database, the system allows creating a shake map caused by a newly recorded earthquake. In addition, the Web GIS environment allows any user, including non-professional to get useful information about a just-occurred event and the possible impact caused by the earthquake shortly after its occurrence. A fault-source model developed for Vietnam was used as a part of the hazard calculation and mapping procedure. All information and results obtained from the system are automatically included in the earthquake bulletins, which will be disseminated national wide afterward by the Vietnam earthquake information and tsunami warning Center.The shake maps produced by the DSS in terms of both Peak Ground Acceleration and intensity values are rapidly available via the Web and can be used for emergency response, public information, loss estimation, earthquake planning, and post-earthquake engineering and scientific analyses. Application of the online decision support system in earthquake warning service can mitigate the earthquake risk and reduce the losses and damages due to earthquakes in Vietnam in future.ReferencesBoore D.M., Joyner W.B. and Fumal T.E., 1994. Estimation of Response Spectra and Peak Acceleration from Wester North American earthquakes: an interim report, USGS open file report, 94-127, Menlo Park, California, United States Geological Survey.Boore D.M. and Atkinson G.M., 2008. Ground-Motion Prediction Equations for the Average Horizontal Component of PGA, PGV, and 5%-Damped PSA at Spectral Periods between 0.01 s and 10.0 s. Earthquake Spectra, 24(1), 1-341.Bui Van Duan, Nguyen Anh Duong, 2017. The relation between fault movement potential and seismic activity of major faults in Northwestern Vietnam. Vietnam J. Earth Sci., 39, 240-255.Campbell K.W. and Bozorgnia Y., 1994. Near-Source Attenuation of Peak Horizontal Acceleration from Worldwide Accelerograms Recorded from 1957 to 1993, Proceedings, Fifth U.S. National Conference on Earthquake Engineering, Chicago, Illinois, July 10-14: V(III), 283-292.Campbell K.W. and Bozorgnia Y., 2008. NGA Ground Motion Model for the Geometric Mean Horizontal Component of PGA, PGV, PGD and 5% Damped Linear Elastic Response Spectra for Periods Ranging from 0.01 to 10s. Earthquake Spectra, 24(1), 1-341.Cauzzi C., Edwards B., Fäh D., Clinton J., Wiemer S., Kastli F., Cua G. and Giardini D., 2014. On the customisation of shakemap for optimised use in Switzerland, 2014. Proceedings of the 2nd European Conference on Earthquake Engineering and Seismology, Istanbul, August 25-29, 1-10.Center for International Earth Science Information Network - CIESIN - Columbia University, 2016. Documentation for the Gridded Population of the World, Version 4 (GPWv4). Palisades NY: NASA Socioeconomic Data and Applications Center (SEDAC). http://dx.doi.org/10.7927/H4D50JX4 Accessed April 2018.Chiou B.S.-J. and Youngs R.R., 2008. An NGA Model for the Average Horizontal Component of Peak Ground Motion and Response Spectra. Earthquake Spectra, 24(1), 1-341.Cornell, C.A., 1968. Engineering seismic risk analysis. Bull. Seis. Soc. Amer., 58(5), 1583-1606.Der Kiureghian and A. S-H. Ang, 1977. A fault rupture model for seismic risk analysis, Bull. Seim. Soc. Am., 67(4), 233-241.Douglas B.M. and Ryall A., 1977. Seismic risk in linear source regions, with application to the San Adreas fault, Bull. Seis. Soc. Amer., 67, 729-754.Marreiros, C. and Carrilho, F., 2012. The ShakeMap at the Instituto de Meteorologia. The proceedings of the 15th World Conference on Earthquake Engineering, Lisbon, Portugal September 24-28.Nguyen Le Minh, et al., 2012. The first peak ground motion attenuation relationships for North of Vietnam. Journal of Asian Earth Sciences. Doi: 10.1016/j.jseaes.2011.09.012.Nguyen Dinh Xuyen and Tran Thi My Thanh, 1999. To find a formula for computing ground acceleration in strong earthquake in Vietnam, J. Sci. of the Earth, 21, 207-213 (in Vietnamese).Pacific Earthquake Engineering Research Center, 2008. NGA model for average horizontal component of peak ground motion and response spectra. Earthquake Spectra, 24(1), 1-341.Tran V.H. and Kiyomiya O., 2012. Ground motion attenuation relationship for shallow strike-slip earthquakes in northern Vietnam based on strong motion records from Japan, Vietnam and adjacent regions, Structural Eng./Earthquake Eng., JSCE, 29, 23-39.Toro G.R., Abrahamson N.A. and Schneider J.F., 1997. Engineering Model of Strong Ground Motions from Earthquakes in the Central and Eastern United States, Seismological Research Letters, January/February.Wald D.J., Worden B.C., Quitoriano V. and Pankow K.L., 2006. ShakeMap Manual. Technical manual, users guide, and software guide.Wald D.L., Wald B. Worden and Goltz J., 2003. ShakeMap - a tool for earthquake response. U.S. Geological Survey Fact Sheet 087-03.Wells D.L. and Coppersmith K.J., 1994. New Empirical Relationships Among Magnitude, Rupture Length, Rupture Width, and Surface Displacement, Bulletin of the Seismological Society of America, 84, 974-1002.

The development of attenuation relationship for Northwest Anatolia region

Ground-motion attenuation relationships using the 1999 Kocaeli earthquake data were developed for the Northwest Anatolia region. This region is seismically active due to its location on Northwest Anatolia Fault Zone and was affected by the 1999 Kocaeli and Duzce earthquakes. Properties of the investigated stations and strong ground-motion data were taken from the Strong Ground Motion Database of Turkey (2017) (TR-NSMN) and Pacific Earthquake Engineering Research Center-Enhancement of Next Generation Attenuation Relationships for Western US (PEER-NGA-West2) database. SeismoSignal software was used in the evaluation of the acceleration records measured in the stations. A generated database for this study contains 369 mainshock and aftershock records, which occurred in the region of 39.39 to 41.03 North (N)/26.04 to 31.73 East (E) coordinates between the years of 1999 (Kocaeli earthquake) and 2006. In this research, peak ground acceleration is greater than 1 gal, and moment magnitude (M W ) is greater than 4.0 and Joyner-Boore distance (R JB ) is 1–344 km. These records were taken from 76 stations located in the investigation area. In addition to these data, 33 mainshock records worldwide were used for recovery of regression coefficients. Therefore, total of 402 data were used in this research. Attenuation relationships obtained from different types of ground were derived from the model generated by Boore et al. (Seismol Res Lett 68(1):128–153, 1997) for shallow earthquakes in North America. In this study, attenuation relation equations were developed by applying nonlinear regression analysis, with Statistical Package for the Social Sciences (SPSS) Statistics 20.0 software for B-C and D class soil according to the National Earthquake Hazards Reduction Program (NEHRP) classification system.

Fuzzy probabilistic seismic hazard analysis with applications to Kunming city, China

China is prone to highly frequent earthquakes due to specific geographical location, which could cause significant losses to society and economy. The task of seismic hazard analysis is to estimate the potential level of ground motion parameters that would be produced by future earthquakes. In this paper, a novel method based on fuzzy logic techniques and probabilistic approach is proposed for seismic hazard analysis (FPSHA). In FPSHA, we employ fuzzy sets for quantification of earthquake magnitude and source-to-site distance, and fuzzy inference rules for ground motion attenuation relationships. The membership functions for earthquake magnitude and source-to-site distance are provided based on expert judgments, and the construction of fuzzy rules for peak ground acceleration relationships is also based on expert judgment. This methodology enables to include aleatory and epistemic uncertainty in the process of seismic hazard analysis. The advantage of the proposed method is in its efficiency, reliability, practicability, and precision. A case study is investigated for seismic hazard analysis of Kunming city in Yunnan Province, People’s Republic of China. The results of the proposed fuzzy logic-based model are compared to other models, which confirms the accuracy in predicting the probability of exceeding a certain level of the peak ground acceleration. Further, the results can provide a sound basis for decision making of disaster reduction and prevention in Yunnan province.

Landslide susceptibility of the Xiangjiaba Reservoir area associated with the Yaziba Fault

Landslides along active fault zones are important hazards during and after earthquakes. They can also cause secondary disasters such as surges, creation of landslide dams, and flooding, especially in reservoir areas. This study analyzed landslide susceptibility of the Xiangjiaba Reservoir area associated with the Yaziba Fault. Analysis of permanent displacement and failure probabilities were used for the regional assessment. Ground motion attenuation relations were selected and compared to produce a peak acceleration map using the Yaziba Fault as the seismic source. Geotechnical parameters were determined by classification of rock groups and geomorphic data were calculated using GIS tools. A distribution of the permanent displacements and a failure probability map was generated. According to the peak ground acceleration (PGA) map, the C-B model was adopted to present the actual conditions of PGA in greater detail while local specific models are more appropriate if there is little measured data. Results indicated larger displacement values and failures are distributed on both sides of the fault, especially in the hanging wall. The feasibility of the research approach was verified using historic earthquake-induced landslides.

An approach for synthesizing tri-component ground motions compatible with hazard-consistent target spectrum - Italian aseismic code application

A versatile approach for synthesizing non-stationary multicomponent ground motions compatible with a given target response spectrum is presented. In conjunction with performance-based structural design, the proposed approach combines a scenario-based procedure to select the target spectra of the three components of the motion, and a stochastic scheme, with an iterative wavelet-based method to generate the artificial time histories. In this context, the selection of an appropriate target spectrum is mandatory to synthesizing accelerograms with proper frequency content, input-energy, effective duration, and inelastic demand. In the scenario-based assessments, the target spectrum is derived directly from an earthquake scenario defined by seismic hazard disaggregation and strong ground-motion attenuation relationships. Firstly, the design spectrum specified by aseismic code provisions is replaced by a set of conditional mean spectra (CMS) for each of the ground motion components. Subsequently, an inverse stochastic dynamics problem, defined by a set of parametric evolutionary power spectra (EPS), is formulated and solved in a point-wise format for each CMS and for the three components of the motion. To improve the matching between the response spectrum of the simulated records and the CMS, an iterative procedure involving the family of harmonic wavelets is then employed. Post-processing for a proper baseline correction of the records is performed to synthesize ground-motions yielding realistic velocity and displacement traces. To illustrate the effectiveness of the approach, extensive numerical results pertaining to the Italian aseismic code provisions are included in this paper. In this regard, Monte Carlo simulations are undertaken to relate the CMSs to the evolutionary power spectrum. In particular, non-constant peak factor expressions via regression analysis are derived for various ground-motion durations. Finally, the nonlinear responses of elasto-plastic SDOF oscillators with different values of the yield strength reduction factor are considered. The oscillators subjected to artificially generated records and a set of natural unscaled and spectrum-compatible accelerograms, are examined in terms of ductility demand and equivalent number of yield cycles.

On the selection of ground–motion attenuation relations for seismic hazard assessment of the Peninsular Malaysia region due to distant Sumatran subduction intraslab earthquakes

The assessment of seismic hazard from seismicity especially those induced by either subduction interface or intraslab earthquakes requires appropriate ground-motion attenuation relations that are tuned to a suitable magnitude–distance range. The Peninsular Malaysia region could be subject to a remarkable seismic hazard due to the large-magnitude, long-distance earthquakes from the Sumatran subduction zone. The earthquakes from Sumatran subduction intraslab zone have not been taken into special consideration in terms of applying the applicable ground-motion relations in the most previous probabilistic seismic hazard assessment (PSHA) studies for the region. This study has attempted first to derive response spectral ground-motion attenuation relations for distant subduction intraslab earthquakes based on the ground-motion data recorded in Peninsular Malaysia, Japan, and Iran. The response spectra database has been compiled from hundreds of ground motions from subduction intraslab events of moment magnitude (M) 5.0–7.7 recorded at sites with hypocentral distance (Rhyp) of about 120 up to 1400km. The proposed empirical relations are for peak ground acceleration (PGA), peak ground velocity (PGV), and 5% damped pseudo-acceleration (PSA) for four site classes (i.e., National Earthquake Hazards Reduction Program (NEHRP) site classes B, C, D, and E). Second, an evaluation of the applicability of the present study, the global and overseas regional ground-motion relations to the Sumatran subduction intraslab earthquakes has been presented in order to develop ground-motion logic tree for seismic hazard assessment in the Peninsular Malaysia region.

Seismic risk assessment of building stocks in Indian context

A relative in-depth review of current earthquake loss estimation software packages are given and compared in this paper. A simple and user-friendly tool for quick seismic risk assessment has been developed for Indian condition using spectrum-based, micro-level-based ground motion attenuation relation. The attenuation relation used here defines a suitable hazard scenario with moment magnitude and location of the earthquake as parameters. A comparison of losses using the proposed software with other open-source software tools has been carried using two case studies situated at different location of India, covering different building typologies. It is observed that the losses estimated by the proposed tool found to be less than the losses estimated by other two tools based on macroseismic intensity and PGA approach. The variation in the loss estimates results mainly from the lack of correlation between the different definitions of seismic hazard and different vulnerability models.

A Refined Vs30 Map for Taiwan Based on Ground Motion Attenuation Relationships

Seismic hazard evaluations require an estimate of the expected ground motion at the site of interest usually by using attenuation relationships. The mean shear-wave velocity over the top 30 m (Vs30) is incorporated in the ground motion attenuation relationships in this study. By comparing the standard deviations of the residuals between the observed and predicted values before and after incorporating the site effect term Vs30, the reduction in standard deviation for the peak ground velocity (PGV) is significantly reduced by about 11%. Clearly, the refined attenuation relationships will be more useful for engineering purposes. Analyzing the site effect term using the amplification factor (relative to a site with Vs30 = 760 m s^(-1)), has revealed that the Changhua Plain, Chianan Plain, Pingtung Valley, Ilan Plain, and Taipei Basin have high values, implying large ground motion amplification. Following a disastrous earthquake, quick assessment and timely peak ground acceleration (PGA) and PGV map reporting will be critical for effective emergency response operations. After an earthquake we can combine the simple attenuation relationships, as determined from Model 1, to provide near real-time estimation and reporting of the PGA and PGV values for the Taiwan area. We can also use the relations between the intra-event site residual and the Vs30 to estimate the Vs30 for stations that have recorded strong motions, but do not yet have Vs30 information. Our approach including sites with estimated Vs30 has resulted in a refined Vs30 contour map that can be used for more realistic seismic hazard assessment for Taiwan. This approach is especially applicable to the foothill and mountain areas.

A Probabilistic Estimate of the Most Perceptible Earthquake Magnitudes in the NW Himalaya and Adjoining Regions

NW Himalaya and its neighboring region (25°–40°N and 65°–85°E) is one of the most seismically hazardous regions in the Indian subcontinent, a region that has historically experienced large to great damaging earthquakes. In the present study, the most perceptible earthquake magnitudes, M p, are estimated for intensity I = VII, horizontal peak ground acceleration a = 300 cm/s2 and horizontal peak ground velocity v = 10 cm/s in 28 seismogenic zones using the two earthquake recurrence models of Kijko and Sellevoll (Bulletin of the Seismological Society of America 82(1):120–134 1992 ) and Gumbel’s third asymptotic distribution of extremes (GIII). Both methods deal with maximum magnitudes. The earthquake perceptibility is calculated by combining earthquake recurrence models with ground motion attenuation relations at a particular level of intensity, acceleration and velocity. The estimated results reveal that the values of M p for velocity v = 10 cm/s show higher estimates than corresponding values for intensity I = VII and acceleration a = 300 cm/s2. It is also observed that differences in perceptible magnitudes calculated by the Kijko–Sellevoll method and GIII statistics show significantly high values, up to 0.7, 0.6 and 1.7 for intensity, acceleration and velocity, respectively, revealing the importance of earthquake recurrence model selection. The estimated most perceptible earthquake magnitudes, M p, in the present study vary from M W 5.1 to 7.7 in the entire zone of the study area. Results of perceptible magnitudes are also represented in the form of spatial maps in 28 seismogenic zones for the aforementioned threshold levels of intensity, acceleration and velocity, estimated from two recurrence models. The spatial maps show that the Quetta of Pakistan, the Hindukush–Pamir Himalaya, the Caucasus mountain belt and the Himalayan frontal thrust belt (Kashmir-Kangra-Uttarkashi-Chamoli regions) exhibit higher values of the most perceptible earthquake magnitudes (M W > 6.0). These spatially-distributed values indicate good agreement with high seismic hazard zones in previously published hazard maps based on seismicity, maximum expected earthquake magnitudes during specific time intervals and maximum expected acceleration. These maps have useful implications in preparing earthquake selection criteria for the anti-seismic design of non-critical structures in the study region.