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Chiou and Youngs PEER-NGA empirical ground motion model for the average horizontal component of peak acceleration and pseudo-spectral
... Nowadays, moment magnitude is routinely estimated from instrumental recordings, and the scaling relations described above are predominantly used to infer the probable dimensions of an earthquake of given magnitude. Applications include distance calculations using finite-fault distance metrics (e.g., Chiou and Youngs 2006), characterization of seismic sources in seismic hazard analysis, and theoretical studies involving forward-modeling of fault slip and resulting ground motions (e.g., Atkinson and Macias 2009;Somerville et al. 2008). However, the reciprocal relations giving moment magnitude as a function of rupture dimensions may still be useful for estimating the moment magnitude of either historical or hypothetical scenario events for which an estimate of the rupture dimensions is available, for instance on the basis of the dimensions of an observed seismic gap or from fault segmentation models. ...
... The scaling of the aspect ratio L:W has also been investigated. For crustal events, a power-law relation has been proposed by Chiou and Youngs (2006) based on the database used in the Next Generation Attenuation (NGA) project (Power et al. 2008). The relatively high value of the exponent in the power-law (b = 3.097) for the Chiou and Youngs (2006) relations leads to very large values when these relations are extended beyond M w 8.0. ...
... For crustal events, a power-law relation has been proposed by Chiou and Youngs (2006) based on the database used in the Next Generation Attenuation (NGA) project (Power et al. 2008). The relatively high value of the exponent in the power-law (b = 3.097) for the Chiou and Youngs (2006) relations leads to very large values when these relations are extended beyond M w 8.0. Closer examination of the data used by Chiou and Youngs (2006) reveals that this behavior is controlled by large strike-slip earthquakes (particularly the largest three with aspect ratios ranging from 6 to 20). ...
... where f 4 and f 5 are period-dependent coefficients. This functional form for f 2 is the same as that used by Chiou and Youngs (2008). Model coefficients and a coded version of the model in Matlab are given as part of the online Appendix to this paper. ...
... The nonlinear term f 2 is parameterized relative to V S30 following the function of Chiou and Youngs (2008), as given in Equation 4. Parameter f 4 controls the overall level of nonlinearity for soft soils and was adjusted to produce a good visual fit to the data and simulation results, as shown by the model curves in Figure 2. Where the slopes from simulations and data diverge (e.g., PSA at T ¼ 0.5 À 3.0 s), more weight is given to slopes derived from data. ...
... Where the slopes from simulations and data diverge (e.g., PSA at T ¼ 0.5 À 3.0 s), more weight is given to slopes derived from data. Parameter f 5 controls the shape of the V S30 dependency of the slope f 2 ; no adjustments relative to the values given by Chiou and Youngs (2008) were found to be needed, so those values were adopted. ...
We analyze NGA-West2 data and simulations to develop a site amplification model that captures ground motion scaling with V S30 and soil nonlinear effects. We parameterize nonlinearity as the gradient of site amplification with respect to peak acceleration for reference (firm) sites. Both data analyses and simulations indicate nonlinearity for sites with V S30 < 500 m∕s and spectral periods T < ∼3 s. Following approximate removal of nonlinear effects from the data, we evaluate V S30 -scaling of ground motions, which is most pronounced for T ≥ ∼0.2 s and saturates for hard rock sites. Regional trends in V S30 -scaling and nonlinearity were not found to be sufficiently robust to justify inclusion in our model. We apply the site amplification model to derive site factors now approved for building code applications. Principal causes of changes relative to previous values are reduction of the reference velocity (at which amplification is unity) to 760 m∕s and reduced nonlinearity.
... The user should be aware of this potential limitation. For the other earthquakes, we adopt a modeling process (Chiou and Youngs, 2008), where we generate 1000 rupture realizations for each event and calculate path measures for each realization. The median and standard deviation of the path parameter are then included in the Bae19 database. ...
... Allen and Hayes, 2017;Blaser et al., 2010). We use the equations provided by Thingbaijam et al. (2017) to estimate the mean and standard deviations of the width and length of ruptures and use Chiou and Youngs (2008) to generate samples of X ratio and Z ratio . We use the Thingbaijam et al. (2017) study because it includes both subduction and shallow crustal earthquakes. ...
This article presents a database of ground motions parameters for earthquakes recorded in Japan by the Kiban Kyoshin network (KiK-net). The database includes all earthquakes in the KiK-net website with magnitude larger than three and recorded between 1996 and the end of 2017. In addition to the information KiK-net provides for each event, we have enriched the database using moment tensor solutions provided by the F-net website and, when available, finite-fault source models from the literature. Various distance measures are computed for each ground motion, including estimates of rupture distance for sufficiently large events, including those with finite-fault source models. Each ground motion is processed using an automated algorithm. Several intensity measures (i.e. spectral acceleration, smoothed and down-sampled Fourier amplitude, Arias intensity, and duration measures) of the processed ground motions are presented in the database. Intensity measures are computed both for surface and borehole records. Finally, the database includes parameters for the recording sites based on shear wave velocity profiles provided by KiK-net.
... Studies made by Sadigh et al, (1997) [12] and Atkinson-Boore (2006) [13] and Chiou-Youngs (2006) [14] were utilized to predict the ground motions for crustal earthquakes. ...
... Studies made by Sadigh et al, (1997) [12] and Atkinson-Boore (2006) [13] and Chiou-Youngs (2006) [14] were utilized to predict the ground motions for crustal earthquakes. ...
Development of seismic hazard maps for Indonesia has been conducted by experts and the results published in many science media, such as seminars and journals. However, published seismic hazard maps of Papua Island, which comprises two territories, Indonesian Papua and Papua New Guinea, are rarely found. In this paper a seismic hazard map of Papua (Papua Indonesia and Papua New Guinea) has been developed. The map was developed using probabilistic seismic hazard analysis. The analysis also used updated earthquake epicenter data up to 2016 and seismic sources studied by seismologists and geologists. The result of the complete seismic hazard analysis was a seismic hazard map of Papua with a hazard level of 10% probability of exceedance over 50 years. From the map, it can be noticed that ground motion across Papua Island is 0.06g-2.01g.
... This is much better to correlate the velocity-slope angle model to geological and geomorphic features. Recent studies have confirmed good correlations between Vs 30 and both slope and geomorphic indicators in Japan [8], and elevation with Vs 30 in Taiwan [9]. Consequently, topographic variations should be an indicator of near-surface geomorphology and lithology to the first order, with steep mountains indicating rock, nearly flat basins indicating soil, and a transition between the end members on intermediate slopes. ...
... Many of the ground motion prediction equations [9][10] are calibrated against seismic station site conditions described with Vs 30 values. As well, various scientists have shown various attenuation relations for numerous countries [11][12][13] based on peak ground or spectral accelerations. ...
In this paper, the ASTER Digital elevation model (DEM) data (medium resolution) is used to produce slope steepness, slope variations in the Syrian territory. The topographic slope corresponding to time-averaged shear wave velocity model (Vs30) developed by Allen and Wald [1] has been used to generate base data of Vs30 map for the Syrian territory. We have found that the values of Vs30 fit the geological and topographic setting of Syria. Site-specific amplification factors (Fa and Fv) maps have been estimated with respect to the empirical equations proposed by Borcherdt [2] . Comparing the estimated values of amplification factors for the Syrian territory shows a good similarity to those assigned in IBC-2006 for the same site-class. The acceleration-independent amplification factor F found to be changing from 1.38 to 5.83. The reclassified amplification factor F map shows clearly the areas with high potential for amplifying ground motion. The obtained maps are highly required by the Syrian anti-seismic design code. These maps have stored numerically. The results show that the slope angle-velocity model is an applicable technique for estimating seismic surface shear wave velocity (Vs30 ). Image processing and remote sensing data, as well as digital elevation model can be used successfully to derive amplification maps.
... The second step for simulating the faults is to estimate the aspect ratio (AR) of the ruptured area. Chiou and Youngs (2008b) developed equations for AR as a function of M W from the NGA-W1 database. Figure A7a compares this relationship to the finite fault models in our Table A1. ...
... database. The finite fault models in our database are sufficiently similar to the previously published equations and so we use the Chiou and Youngs (2008b) equations for normal and strike slip events. However, the AR relationship for reverse faults tends to give values that are too large, particularly at larger magnitudes. ...
The Kiban-Kyoshin network (KiK-net) database is an important resource for ground motion (GM) studies. The processing of the KiK-net records is a necessary first step to enable their use in engineering applications. In this manuscript we present a step-by-step automated protocol used to systematically process about 157,000 KiK-net strong ground motion records. The automated protocol includes the selection of the corner frequency for high-pass filtering. In addition, a comprehensive set of metadata was compiled for each record. As a part of the metadata collection, two algorithms were used to identify dependent and independent earthquakes. Earthquakes are also classified into active crustal or subduction type events; most of the GM records correspond to subduction type earthquakes. A flatfile with all the metadata and the spectral acceleration of the processed records is uploaded to NEEShub (https://nees.org/resources/7849, Dawood et al. 2014).
... The results show that the ground motion is amplified by factors 30-100 % at some locations in the frequency range from 2 to 15 Hz. Many empirical equations have been developed for prediction of site conditions in terms of velocity (e.g., Boore et al. 1997;Chiou and Youngs 2006). As well as numerous scientists have shown various attenuation relations for their own or other countries (Singh et al. 1996;García et al. 2005;Stromeyer and Grünthal 2009) based on peak ground acceleration. ...
... Topographic variations should be an indicator of near-surface geomorphology and lithology to the first order, with steep mountains indicating rock, nearly flat basins indicating soil, and a transition between the end members on intermediate slopes. In addition, several studies have confirmed good correlations between V 30 S and both slope and geomorphic indicators in Japan (e.g., Matsuoka et al. 2005) and elevation with V 30 S in Taiwan (e.g., Chiou and Youngs 2006). ...
The microzonation map of any region is important to plan proper design of building, especially in seismic prone region. This paper discusses the use of remote sensing data and digital elevation model (DEM) in evaluating the site-specific conditions for microzonation map of Syria. We have made efforts to quantify the dynamic properties of surface soil for Syrian territory in terms of shear velocity (Formula presented.) and predominant period (Formula presented.) and have prepared a microzonation map that divides the surface soil into various classes according to Syrian building code. In the present study, we have used ASTER satellite DEM of high resolution (30 × 30 m pixel size) to produce slope map of the Syrian territory. The slope angle -velocity (Formula presented.) model is used to generate the base velocity map. The map of predominant period is also created. We present microzonation maps with respect to dynamic properties of soil ((Formula presented.), (Formula presented.)) that show four classes. The produced site-class characterization maps are very much required by Syrian anti-seismic design code.
... Este modelo se calculó con datos de terremotos de corteza superficiales en regiones activas de todo el globo, aunque la mayor parte de éstos provino de California. Con respecto a estos datos, se ha demostrado que son consistentes con los de otras regiones activas como Japón, la cuenca mediterránea con un modelo de Ambraseys, anterior al usado, de 1996, e Italia (Chiou andYoungs, 2006). Este modelo se creó con la premisa de que los movimientos de tierra de estas regiones pudieran combinarse, puesto que son similares. ...
... Se graficó el espectro de respuesta del sismo original de cada una de las estaciones que pudieron clasificarse entre suelo y roca, sobre las ecuaciones empíricas de movimiento del suelo de Ambraseys y de Chiou and Youngs (2006). (ANEXO 5.I). ...
... As the Himalayas are characterised by shallow crustal earthquakes, the ground motion prediction equation is selected according to the assessment carried out by Nath and Thingbaijam (2011). Several attenuation relationships have been developed considering worldwide database for the shallow crustal earthquakes, which mainly includes Zhao et al. (2006), Boore and Atkinson (2008), Campbell and Bozorgnia (2008), Chiou and Youngs (2008), Akkar and Bommer (2010) and these have been used to estimate PGA. Depth to shear-wave velocity V s = 1.0 km/s (Z 1.0 ) is estimated using the relation between Z 1.0 and V S30 given by (Chiou and Youngs 2008) while depth to V S = 2.5 km (Z 2.5 ) is assigned 2 km following Boore and Atkinson (2008). ...
... Several attenuation relationships have been developed considering worldwide database for the shallow crustal earthquakes, which mainly includes Zhao et al. (2006), Boore and Atkinson (2008), Campbell and Bozorgnia (2008), Chiou and Youngs (2008), Akkar and Bommer (2010) and these have been used to estimate PGA. Depth to shear-wave velocity V s = 1.0 km/s (Z 1.0 ) is estimated using the relation between Z 1.0 and V S30 given by (Chiou and Youngs 2008) while depth to V S = 2.5 km (Z 2.5 ) is assigned 2 km following Boore and Atkinson (2008). In the present work, shear wave velocity (V s30 ) is taken as 1300 m/s, which means peak ground motion is computed at bed rock level. ...
The Himalayan region has undergone significant development and to ensure safe and secure progress in
such a seismically vulnerable region there is a need for hazard assessment. For seismic hazard assessment,
it is important to assess the quality, consistency, and homogeneity of the seismicity data collected from
different sources. In the present study, an improved magnitude conversion technique has been used to
convert different magnitude scales to moment magnitude scale. The study area and its adjoining region
have been divided into 22 seismogenic zones based upon the geology, tectonics, and seismicity including
source mechanism relevant to the region. Region specific attenuation equations have been used for seismic
hazard assessment. Standard procedure for PSHA has been adopted for this study and peak ground
motion is estimated for 10% and 2% probability of exceedance in 50 years at the bed rock level. For the
10% and 2% probability of exceedance in 50 years, the PGA values vary from 0.06 to 0.36 g and 0.11 to
0.65 g, respectively considering varying b-value. Higher PGA values are observed in the southeast part
region situated around Kaurik Fault System (KFS) and western parts of Nepal.
... the findings of Mai et al. (2005) for crustal events and the hypocenter distribution of normal events described in Appendix B of Chiou and Youngs 2006). In these simulations and in the following ones, the Fukuoka slip distribution (fourth plot in Figure 6) was adopted. ...
... • Three hypocenter positions, lying in the lower half of the fault plane (white stars in Figure 6), following the indications of Chiou and Youngs (2006) for normal events. ...
This work proposes a novel approach for probabilistic seismic hazard analyses (PSHA) in the near field of active earthquake faults, in which deterministically computed ground motion scenarios, replacing empirically predicted ground motion values, are introduced. In fact, the databases of most ground motion prediction equations (GMPEs) tend to be insufficiently constrained at short distances and data may only partially account for the rupture process, seismic wave propagation and three-dimensional (3-D) complex onfigurations. Hence, herein, 3-D numerical simulations of a Mw 6.4 earthquake rupture of the Sulmona fault in Central Italy, are carried out through the spectral element code GeoELSE ( f < 2.5 Hz), and the results are introduced in a PSHA, exploiting the capabilities of CRISIS2008 code. The SH results obtained highlight the combined effects of site, basin, and topographic features, and provide a “highresolution” representation of the hazard in the Sulmona Basin, particularly at long periods. Such representation is expected to be more realistic than those based simply on a GMPE
... As the Himalayas are characterised by shallow crustal earthquakes, the ground motion prediction equation is selected according to the assessment carried out by Nath and Thingbaijam (2011). Several attenuation relationships have been developed considering worldwide database for the shallow crustal earthquakes, which mainly includes Zhao et al. (2006), Boore and Atkinson (2008), Campbell and Bozorgnia (2008), Chiou and Youngs (2008), Akkar and Bommer (2010) and these have been used to estimate PGA. Depth to shear-wave velocity V s = 1.0 km/s (Z 1.0 ) is estimated using the relation between Z 1.0 and V S30 given by (Chiou and Youngs 2008) while depth to V S = 2.5 km (Z 2.5 ) is assigned 2 km following Boore and Atkinson (2008). ...
... Several attenuation relationships have been developed considering worldwide database for the shallow crustal earthquakes, which mainly includes Zhao et al. (2006), Boore and Atkinson (2008), Campbell and Bozorgnia (2008), Chiou and Youngs (2008), Akkar and Bommer (2010) and these have been used to estimate PGA. Depth to shear-wave velocity V s = 1.0 km/s (Z 1.0 ) is estimated using the relation between Z 1.0 and V S30 given by (Chiou and Youngs 2008) while depth to V S = 2.5 km (Z 2.5 ) is assigned 2 km following Boore and Atkinson (2008). In the present work, shear wave velocity (V s30 ) is taken as 1300 m/s, which means peak ground motion is computed at bed rock level. ...
Northwest Himalaya is one of the seismically most active regions of the world. For seismic hazard assessment, it is important to calculate the seismicity parameters for every source zones. Homogenous earthquake catalog is a basic input for seismic hazard calculation. General orthogonal regression relation is used to convert different magnitude scales into a single moment magnitude scale. Declustering method is used to remove any non-Poissonian behaviour from earthquake catalogue. The NW Himalaya and its adjoining region are divided into twenty two seismic source zones based upon the seismicity, tectonics of the region and fault plane solution. Entire Magnitude Range Method (EMR) is adopted to estimate the magnitude of completeness because this method is stable under most conditions and provides a comprehensive seismicity model. Earthquake dataset for the period 1964-2011 has been used to determine of Mc values for different seismic zones. The Mc value valid for the entire NW Himalaya region can be considered to be 4.7 for the catalogue period 1964-2011. The 'b' value ranges between 0.67-1.33 for different source zones. The value of parameter 'a' increases with the seismicity of the region. This homogenized earthquake catalog and seismicity parameters are the basic input for seismic hazard assessment.
... The GMPE selected in this study was based on the seismotectonic conditions classified due to the earthquake source mechanisms. This study applied the GMPE formula of Youngs et al. 1997 [25][26][27] were selected for the shallow crustal fault mechanisms. The analysis used the Logic tree model in considering the epistemic uncertainty [28] with the same weighting in each GMPE as shown in Figure 2. The magnitude relative distribution for each earthquake source was modelled using the exponential model of Gutenberg-Richter and characteristic with weights of 0.34 and 0.66, respectively. ...
The M6.1 earthquake which hit Malang and its surroundings in 2021 resulted in fatalities and over 10,400 damaged houses. Several seismicity studies have been carried out for Malang region, but no specific studies have implied the M6.1 Malang earthquake yet. This study addresses such gap by investigating the Spatio-temporal b-value of Gutenberg-Richter Law and generating the microzonation maps of spectral acceleration by considering the effects of the M6.1 Malang earthquake. The earthquake data compiled from the national and international earthquake catalogs were homogenized into a moment magnitude scale. The b-value analysis was calculated using the Maximum Likelihood method and spatio-temporal mapping. Several ground motion prediction equations (GMPEs) were selected for subduction and shallow crustal earthquake sources to generate probabilistic seismic hazard analysis (PSHA). PSHA was conducted using the 2% probability of exceedance in 50 years. The results show that the b-value after the M6.1 Malang earthquake still tends to decrease, indicating a relatively-high stress level which accommodates the potential for large earthquakes in the future. The microzonation maps for Malang region show that the southern part of Malang has a higher spectral acceleration value than the others. Therefore, these findings can be considered in the future disaster mitigation plan.
... However, the TE-approach showed undulating fluctuation, which was severe for V s30 values \ 400 m/s but less notable in the range 400-520 m/s. The lower-velocity material is distributed on the lower slopes (Matsuoka et al. 2005;Chiou et al. 2006); therefore, we infer that the violent fluctuation of V s30 values appears in the plain area under the TE-approach. ...
Although time-averaged shear wave velocity to the depth of 30 m (Vs30) is an important indicator of earthquake site effects, it is difficult to obtain. Several proxies have been used either individually or in combination to infer Vs30 values during seismic hazard estimation under limited observational conditions. Sichuan Province is an area highly prone to earthquakes. Complex geological structures and lack of drilling sites mean that it is particularly important to establish a suitable approach for the estimation of Vs30 values for site classification. This study compared the application of three proxy-based approaches—geology-based, topographic slope-based, and terrain-based—to the estimation of Vs30 values in Sichuan Province. The results revealed that the residual between the measured logVs30 values and the estimations derived from the terrain-based approach was smallest, indicating best predictability. Stability analysis of the three approaches also showed that the terrain-based approach performed best. However, its performance in the plain area was poor, that is, the Vs30 values were mostly underestimated. This might indicate that the old strata, hard rock, and alluvial deposits formed by Quaternary glacier sediments were not identified appropriately in the plain area, highlighting the need for localized corrections.
... Ahmad (2016) has used satellite data (ASTER) to develop seismic microzonation map of Syria. Many studies have shown good correlations between V S30 and topographic slope, elevation and geomorphic indicators (Matsuoka et al. 2005;Allen andWald 2007, 2009; Lemoine et al. 2012;Matsuoka et al. 2006;Chiou and Youngs 2006). Wald and Allen (2007) have correlated V S30 with topographic slope and provided estimate of V S30 for active and stable continental regions. ...
Detailed analysis of digital topographic data of 1 and 3 arcsec resolutions derived from Advanced Spaceborne Thermal Emission Reflection Radiometer (ASTER) and Shuttle Radar Topography Mission (SRTM) satellites has done to evaluate seismic site parameters. We have developed slope angle-velocity (V S30) relationship for the estimation of shear velocity and site class prediction. The accuracy of V S30 estimation has been improved using high resolution data. The results are discussed in the present work, show good agreement with the field observations. In Damascus area, the velocity (V S30) varies in the range 280-1006, 283.8-1036.29 and 215.3-937.8 m/s, respectively using ASTER 1 arcsec, SRTM 1 arcsec and SRTM 3 arcsec data. The short-period amplification (Fa) changes in the range 0.936-1.587 and the mid-period amplification (Fv) in the range 1.0193-2.359, showing dominance of C and D site classes in Damascus region. The 3 arcsec topographic data show good correlation with the geological settings of Damascus area whereas 1 and 3 arcsec resolutions provide good estimate of seismic site conditions (velocity, fundamental period and amplification factors), and site-class maps. These maps were compared with the low resolution topographic data (30 arcsec), and found detailed features with increasing resolution from 30 arcsec to 1 arcsec. 2 In comparison with shear velocity V S30 measurements, statistical analysis indicates an improvement over low-resolution topography. Our results show that V S30 using slope angle topography is in general, accurate and its use may be very inexpensive and less time consuming to evaluate seismic site conditions by the Civil, Geotechnical and Earthquake Engineers.
... ASCE/SEI 7-10. Campbell and Bozorgnia (2008;CB), and Chiou and Youngs (2008;CY)) as a function of period and ground motion level as referenced to 1100 m/s (AS, CB), 1130 m/s (CY), and 760 m/s (BA). The spreadsheets compiled from these values were provided by Stewart and Seyhan (written commun. ...
... ASCE/SEI 7-10. Amplification values were provided by the four developers, Abrahamson and Silva (2008; referred to as AS), Boore and Atkinson (2008; BA), Campbell and Bozorgnia (2008;CB), and Chiou and Youngs (2008;CY)) as a function of period and ground motion level as referenced to 1100 m/s (AS, CB), 1130 m/s (CY), and 760 m/s (BA). The spreadsheets compiled from these values were provided by Stewart and Seyhan (written commun. ...
Vs30, defined as the average seismic shear-wave velocity from the surface to a depth of 30 meters, has found wide-spread use as a parameter to characterize site response for simplified earthquake resistant design, as implemented in building codes worldwide. Vs30, as initially introduced by the author in 1992 for the US 1994 NEHRP Building Code provisions, provides unambiguous definitions of site classes and site coefficients for site-dependent response spectra based on correlations derived from extensive borehole logging and comparative ground-motion measurement programs in California. Subsequent use of Vs 30 for development of strong ground motion prediction equations (GMPEs) and measurement of extensive sets of Vs borehole data have confirmed the previous empirical correlations and established correlations of Vs30 with Vsz at other depths. These correlations provide closed form expressions to predict Vs30 at a large number of additional sites and further justify Vs30 as a parameter to characterize site response for simplified building codes, GMPEs, ShakeMap, and seismic hazard mapping.
... Slope of topography influences shear wave as more competent (high-velocity) materials are likely to maintain a steep slope, whereas nearly flat basins indicate the presence of soil, and a transition between the end members is observed on intermediate slopes. In general, steeper slopes have higher shear wave velocity (Chiou and Youngs 2006;Matsuoka et al. 2005;Wald and Allen 2007). ...
... Topographic variations are an effective index of near-surface geomorphology and lithology, with steep mountains representing rocky terrain and flat basins indicating soil, and intermediate slopes representing a transition between rock and soil (Allen and Wald, 2009). Matsuoka et al. (2005) has found good correlations between V S30 and topographic slope in Japan, similar studies have been done by Chiou and Youngs (2006) for Taiwan and by Allen and Wald (2009) for California. In present study site characterization for entire India has been done based on the slope map. ...
This chapter predominantly discuss about the role of Local site conditions on the amplification of seismic waves and the resulted earthquake disasters. In-depth discussions are made on the various local site conditions which influence the ground shaking. Different available methods for the assessing the local site conditions are presented in this chapter. Various codal provisions for site classifications are also discussed here. This chapter also presents the assessment of local site effect at micro and macro-level using the appropriate methodologies.
... As the Himalayan region is characterized by shallow crustal earthquakes, the ground motion prediction equations selected for this regions are Akkar and Bommer (2010), Boore and Atkinson (2008), Campbell and Bozorgnia (2008), Chiou and Youngs (2008) and Zhao et al. (2006). The above-mentioned selected ground motion prediction equations and their parameters are shown in Table 2. ...
In view of active seismic status of the Himalayan belt and continued developmental activities in mountainous states, it is imperative to update knowledge of seismic hazard incorporating latest knowledge on earthquake occurrence and attenuation process. The present research work delivers new-generation probabilistic seismic hazard information for northwest and central Himalayan region. We adopted a noble approach following a zone-free method, first time, for the Himalayan region to estimate the ground motion at bedrock level, the results of which are compared with the contemporary zoning method for the same area. Employing new-generation ground motion prediction equations, peak ground acceleration and spectral acceleration have been estimated in the region for return periods of 475, 975 and 2475 years (10, 5 and 2% exceedance in 50 years, respectively). The zone-free method predicted maximum ground motions in two areas Kashmir valley and eastern part of the Uttarakhand and the westernmost part of the Nepal. The ground motion ranges from 0.04 to 0.60 g for 2475-year return period.
... In the study area, variations in elevation and slopes are observed. A good correlation between V S 30 and both slope and geomorphic indicators reported by Matsuoka et al. (2005) for Japan and elevation with V S 30 by Chiou and Youngs (2006) for Taiwan. In the present study, we have considered slope as one of the important factors since slope configuration and steepness play an important role in conjunction with lithology. ...
The present paper discusses the use of an integrated remote sensing and Geographical Information System (GIS) techniques for evaluation of seismic hazard areas in Syria. In the proposed approach, we have used the Advanced Spaceborne Thermal Emission and Reflection Radiometer (Aster) satellite data, digital elevation data (30 m resolution), earthquake data, and active tectonic maps. Many important factors for evaluation of seismic hazard were identified and corresponding thematic data layers (past earthquake epicenters, active faults, digital elevation model, and slope) were generated. A numerical rating scheme has been developed for spatial data analysis using GIS to identify ranking of parameters for the evaluation of seismic hazard. The resulting earthquake potential map delineates the area into different relative susceptibility classes: high, moderate, low and very low. The potential earthquake map was validated by correlating the obtained different classes with the local probability that produced using conventional analysis of observed earthquakes. Using earthquake data of Syria and the peak ground acceleration (PGA) data are included in the model to develop final seismic hazard map based on Gutenberg-Richter (a and b values) parameters and the concepts of local probability and recurrence time. The application of the proposed technique in Syrian region indicates that this method provides good estimate of seismic hazard map compared to those developed from traditional techniques deterministic (DSHA) and probabilistic seismic hazard (PSHA). For the first time, we have used numerous parameters in preparation of seismic hazard map. The evaluation of seismic hazard maps using the proposed model is found to be very realistic.
... The three NGA relationships that the USGS has adopted to generate the 2007 seismic hazard maps for the Western US were developed by Boore and Atkinson [4], Campbell and Bozorgnia [5], and Chiou and Youngs [6]. Information on the relationships is available at http://peer.berkeley.edu/products/rep_nga_models.html. ...
The Next Generation Attenuation (NGA) models for shallow crustal earthquakes in the Western United States, like most other ground motion attenuation relationships, predict the geometric mean of horizontal spectral demand. In the near-fault region, the geometric mean spectral demand can be much smaller than the maximum spectral demand for a pair of ground motions. One hundred and forty seven pairs of ground motion records for earthquakes with moment magnitude greater than 6.5 and site-to-source distance smaller than 15 km were selected from the NGA strong motion dataset to study the relationship between maximum and geometric mean demands. The ratio of maximum to geometric mean spectral demand for each pair of ground motions was calculated. The ratio showed clear dependency on period and the Somerville directivity parameters. In a median sense, the geometric mean from the NGA models conservatively predicts the maximum spectral demand at 0.1 and 0.2 seconds and underestimates the maximum demand for periods of 0.5 and greater.
... They observed differences in small-to-moderate magnitude data recorded in central and southern California, but this regional difference no longer exists in large-magnitude earthquakes and becomes at least insignificant for data with magnitude larger than M 6.0. Chiou and Youngs (2007) proposed an interim model and compared it with the PGA data from small-to-moderate earthquakes in southern California. This model on average underpredicts or overpredicts the PGA values depending on the applied magnitude intervals. ...
The original aim of the present study was to test the efficiency of some selected ground motion prediction equations (GMPEs) against small-to-moderate data recorded in the Iranian plateau. For this purpose, we applied three statistical tests including the Nash-Sutcliffe model efficiency coefficient (Nash and Sutcliffe, 1970), LH and LLH methods (Scherbaum et al. 2004, 2009) to assess performance of eight GMPEs against a comprehensive databank from small-to-moderate magnitudes data in Iran. Two of the candidate models were selected form Japanese models and rest of them were chosen from regions with shallow crustal earthquakes including local models corresponding to the Iranian earthquakes, regional models established for Middle East and Euro-Mediterranean regions, and global models (developed for shallow crustal environments). We analyzed a high quality dataset composed of 937 ground-motion records from 296 Iranian earthquakes with moment magnitude ranging between 3.9 and 5.0 and epicentral distances up to 100 km. In conclusion, the Zafarani et al. (2015) as a ground motion model valid for a magnitude range as small as M4.0 is the only model that shows good consistency with the recorded data over all frequencies. This emphasizes the importance of region-dependent anelastic attenuation and necessity to develop more elaborate local GMPEs for small-to-moderate earthquakes, which are also very important from the viewpoint of epistemic uncertainty.
... For the ruptures with no finite fault solution available, the center of the rupture was taken at the centroid reported by CMT. R rup values computed following Chiou and Youngs (2008) methodology is also reported (tagged as RupDist_CSN). Interplate events with no CMT report are relatively small in magnitude (between Mw 4.6 -6.0) and number, for these events the centroid was assumed at the hypocenter location. ...
The Nazca-South American plate boundary produces large magnitude events (Mw > 8) every 20 years in the coast of Chile. This work describes a public ground motion database that contains 3572 records from 477 earthquakes, and 181 seismic stations, which includes the recent 2015 Mw 8.3 Illapel earthquake. The dataset is controlled by subduction interface and inslab events. The oldest event included is Valparaiso (1985), and the magnitude span is 4.6–8.8 Mw. The source-to-site distance metrics reported are the closest distance to the rupture plane (Rrup), epicentral (Repi), and hypocentral (Rhyp) distances, with a range for Rrup from 20 to 650 kms. Site characterization is based on Vs30, ranging from 110 to 1951 m/s. Intensity measures included are peak ground acceleration, spectral acceleration values from 0.01 to 10s, Arias Intensity, and peak ground velocity. Each record was uniformly processed component by component. A flatfile with the related metadata and the spectral accelerations from processed ground motions is available at NEEShub (Bastías and Montalva, 2015).
... ShakeMap was used to generate 112 earthquake scenarios, each with in turn the GMPEs of Boore and Atkinson (2008;BA08) or Chiou and Youngs (2008;CY08). ShakeCast applied these to the 1831 bridges of the Nevada bridge inventory. ...
This case study evaluates the vulnerability of Nevada bridges relative to earthquake hazard using two different methods. First, a distributed set of 112 realistic earthquake scenarios were processed with USGS program ShakeMap, and site-specific ground motion levels extracted for 1831 bridges in Nevada using ShakeCast. Second, using hazard curves underlying the 2014 USGS National Seismic Hazard Map (NSHM), return periods for earthquakes causing extensive damage to bridges were extracted and compared to the 1000-year design level adopted by the AASHTO. Lower capacities than those used in ShakeCast were proposed for five continuous bridge types based on a literature review. Scenarios provide points in a deterministic seismic hazard approach, with large earthquakes on known faults. NSHM hazard curves are based on a probabilistic approach. A graphical method is presented to unite the two approaches. A list of potentially vulnerable bridges was developed for Nevada Department of Transportation (NDOT) use in bri...
... GMPEs are commonly specified using constant ϕ lnY (e.g., Boore et al., 1997;Chiou and Youngs, 2006;Boore and Atkinson, 2008). Some of the more recent GMPEs have incorporated earthquake-magnitude dependence of ϕ lnY (e.g., Abrahamson and Silva, 2008;Chiou and Youngs, 2008). ...
We investigate near-field ground-motion variability by computing the seismic wavefield for five kinematic unilateral-rupture models of the 1992 M-w 7.3 Landers earthquake, eight simplified unilateral-rupture models based on the Landers event, and a large M-w 7.8 ShakeOut scenario. We include the geometrical fault complexity and consider different 1D velocity-density profiles for the Landers simulations and a 3D heterogeneous Earth structure for the ShakeOut scenario. For the Landers earthquake, the computed waveforms are validated using strong-motion recordings. We analyze the simulated ground-motion data set in terms of distance and azimuth dependence of peak ground velocity (PGV). Our simulations reveal that intraevent ground-motion variability phi(ln)(PGV) is higher in close distances to the fault (< 20 km) and decreases with increasing distance following a power law. This finding is in stark contrast to constant sigma-values used in empirical ground-motion prediction equations. The physical explanation of a large near-field phi(ln)(PGV) is the presence of strong directivity and rupture complexity. High values of phi(ln)(PGV) occur in the rupture-propagation direction, but small values occur in the direction perpendicular to it. We observe that the power-law decay of phi(ln)(PGV) is primarily controlled by slip heterogeneity. In addition, phi(ln)(PGV), as function of azimuth, is sensitive to variations in both rupture speed and slip heterogeneity. The azimuth dependence of the ground-motion mean mu(ln)(PGV) is well described by a Cauchy-Lorentz function that provides a novel empirical quantification to model the spatial dependency of ground motion.
... Slope of topography influences shear wave as more competent (high-velocity) materials are likely to maintain a steep slope, whereas nearly flat basins indicate the presence of soil, and a transition between the end members is observed on intermediate slopes. In general, steeper slopes have higher shear wave velocity (Chiou and Youngs 2006;Matsuoka et al. 2005;Wald and Allen 2007). ...
The ongoing intra-continental collision between the Indian and Eurasian plates along the Himalayas has resulted in many damaging earthquakes with severe damages to man-made structures and natural landscapes due to ground shaking and ground failure, which in turn depends on geomorphological, geological and geophysical variables. Seismic susceptibility models are developed for Gangtok City by combining all the three variables using both knowledge-driven and data-driven methods on facet and grid cell terrain units. Finally, the results are critically evaluated by validation with the earthquake intensity data recorded during earthquake events. First-stage modelling attempt using different knowledge-driven methods on different terrain units shows bi-modal data distribution with low predictability due to extremely rugged topography with wide altitudinal variations within short distances. Second-stage modelling of separated population by using the same methodologies increases model predictability in which one model method describes the higher topographic levels better and the other model method is found to be better for lower topographic levels. Seismic susceptibility of the area is best described by composite models, combining different best methods of fine classification for lower and higher topographic levels having the same mapping/terrain units. Comparison of the composite models shows that the terrain unit does not play a significant role but the type of models selected determines the best possible seismic susceptibility map of the area.
... High correlation is observed between the better-constrained lithologic model and shear wave velocity and the earlier may be used as a proxy for the latter (Gomberg et al., 2003). Geologically, the Gangtok City is settled over the coarse grained garnet mica schist of Daling Group either sides flanked by two thrust contacts ( Fig. 2 Japan (Matsuoka et al., 2005) and in Taiwan (Chiou and Youngs, 2006) respectively. Wald and Allen (1965) described a technique to derive first-order site-condition maps directly from topographic data. ...
... E Q -T A R G E T ; t e m p : i n t r a l i n k -; e 5 ; 4 1 ; 1 1 8R i ðTÞ ¼ ln ðS a ðTÞÞ sim;i À ln ðS a ðTÞÞ GMPE;i (5) where index i refers to a particular location where ground motions were simulated (latitude and longitude), S a (T) sim,i refers to the 5% damped spectral acceleration of the simulated motion for oscillator period T at location i, S a (T) GMPE,i refers to the median spectral acceleration for location i predicted by a GMPE considering the earthquake magnitude, site-source distance, and site condition (different for a given site in the BB and HF simulations), and R i is the residual in natural logarithmic units. Residuals were calculated relative to the , Boore and Atkinson (2008), Campbell and Bozorgnia (2008), and Chiou and Youngs (2008) GMPEs (referred to subsequently as AS, BA, CB, and CY). Star et al. (2011) found residuals R i (T) to have a statistically significant slope with respect to rupture distance (R rup ) for the ShakeOut event for response spectral accelerations at periods under 5 sec. ...
Broadband ground motion simulation procedures typically utilize physicsbased modeling at low frequencies, coupled with semi-stochastic procedures at high frequencies. The high-frequency procedure considered here combines deterministic Fourier amplitude spectra (dependent on source, path, and site models) with random phase. Previous work showed that high-frequency intensity measures from this simulation methodology attenuate faster with distance and have lower intra-event dispersion than in empirical equations. We address these issues by increasing crustal damping (Q) to reduce distance attenuation bias and by introducing random site-to-site variations to Fourier amplitudes using a lognormal standard deviation ranging from 0.45 for Mw < 7 to zero for Mw 8. Ground motions simulated with the updated parameterization exhibit significantly reduced distance attenuation bias and revised dispersion terms are more compatible with those from empirical models but remain lower at large distances (e.g., > 100 km).
... Bars correspond to the 20th and 80th percentiles. The graphs are ordered vertically according to the attenuation model used, as follows: McVerry et al. (2006), Boore & Atkinson (2006), Chiou & Youngs (2006), and Abrahamson & Silva (1997). An assumed PBR age of c. 40ka would correspond to c. five Dunstan Fault earthquakes (5 on the x-axis). ...
We have undertaken a detailed cosmogenic dating study of precariously-balanced rocks (PBRs) in the central Otago province, New Zealand to understand the age and genesis of PBRs to an unprecedented level of detail within the temperate-humid New Zealand environment. Previous PBR studies have been restricted to desert environments. At face value our 10 Be dates indicate that the numerous PBRs in the Clyde area of central Otago have been unstable for around 40ka, although previous central Otago-based studies raise the possibility that the ages are apparent and the PBRs are much younger (<10ka). Consideration of these age uncertainties raises the question as to whether the PBRs have experienced multiple large near-field earthquakes on the Dunstan Fault, or no such earthquakes, considering the long recurrence interval of the fault. Resolution of this issue might therefore have significant implications for near-fault motions for the Dunstan Fault. The dating of buried soils at the base of the PBR to resolve the issue is the goal of current efforts.
... The same report estimated the 84 th percentile ground motions in the maximum direction of response relative to the median spectral response accelerations of the new NGA relations. Near active sources (in the WUS), 84 th percentile ground motion in the maximum direction of response is about 200 percent (1.8 x 110 percent) of the 5 percent damped, short-period spectral response acceleration, and about 230 percent (1.8 x 130%) of the 5 percent damped, 1-second spectral response acceleration of the new NGA relations for GMRotI50 (average value of the three NGA relations). 1. B-A (Boore and Atkinson, 2007), C-B (Campbell and Bozorgnia, 2007), C-Y (Chiou and Youngs, 2006) ...
This paper describes work by the Seismic Design Procedures Reassessment Group (SDPRG) of Project 07 to update the seismic design maps and procedures of the 2009 NEHRP Recommended Provisions. Project 07 was a joint effort of the Building Seismic Safety Council (BSSC), the Federal Emergency Management Agency (FEMA and the United States Geological Survey (USGS). As part of Project 07, the SDPRG worked with the USGS to incorporate new (2008) hazard data and improved earthquake ground motion criteria in the 2009 Provisions. Work by SDPRG resulted in three significant changes to design ground motions: (1) "probabilistic" ground motions are now defined in terms of uniform risk, rather than uniform hazard, (2) ground motion intensity is now defined in terms of the maximum spectral response in the horizontal plane, and (3) "deterministic" ground motions are now defined by 84th percentile spectral response (rather than 1.5 times median spectral response).
... By default, the intensity map is shown, although peak ground acceleration and velocity as well as spectral response maps are easily accessed via the second row of links above the map. Source USGS (2009) the methodology employed including the use of Chiou and Young (2006) representation of peak ground and spectral values, the Wald et al. (1999) relationship between Peak Ground Acceleration (PGA), Peak Ground Velocity (PGV), and Modified Mercalli Intensity (MMI), and Allen and Wald (2009) Intensity Prediction Equations (IPEs) to relate ground motion to intensity for the two scenarios used in this study. ...
The focus of the Hazus earthquake model has
been largely U.S. centric due to a lack of standardized
building-infrastructure data formats applicable elsewhere.
In a combined effort between FEMA Region VIII and the
Universidad de Los Andes, Venezuela, the present study
uses the Hazus 2.1 software to simulate earthquake loss
estimations for Venezuela. Population totals and demographic
distributions were developed using Oak Ridge
National Labs Landscan 2008 population data and the
census 2011 for Venezuela. The accuracy of the model was
further enhanced for Mérida State, located in western
Venezuela, by collecting, incorporating, and developing
region and specific inventories including soil maps, liquefaction
and landslide susceptibility studies, demographic
data, and building inventory information. We used USGS
ShakeMaps scenarios for two potential earthquake events
with peak ground accelerations proposed within Performance
Based Seismic Engineering of Buildings, VISION
2000 recommendations. The region has not witnessed an
earthquake with a magnitude greater than M 7 in the last
120 years. Given the historical record of seismicity and the
seismotectonics in the region, it becomes increasingly
important to understand the potential implications from
moderate to large earthquakes in Mérida State, Venezuela.
This paper is aimed to construct Rjb for PESMOS and COSMOS database representing the earthquakes triggered in Indian sub-continent. Rjb, by definition, is the shortest distance from the site to the horizontal projection of rupture plane and that can be constructed using simple geometry provided the required information is available. In practice, the uncertainty associated with this information offers several challenges which are addressed in this paper. First, a vector algebra-based approach is proposed for estimating epicentral distance and azimuth. Second, a set of empirical relationships are proposed to estimate the rupture plane from the moment magnitude using a dataset of 354 earthquakes based on tectonic settings and focal mechanisms. Third, a step-by-step process of computing Rjb is developed considering the uncertainty in the location of hypocentre on the rupture plane. Two approaches are considered for this purpose, namely, i) areal grid representation, and ii) hypocenter distribution model. While the former assumes equally likely hypocenter over the rupture plane, the latter requires construction of hypocenter distribution model from the prior database. Fourth, the process is extended to account for the uncertainty in available information of strike and/or dip. The proposed framework is assessed against a total of 4247 records from PEER database with Rjb reported based on geometry and location of rupture plane. The framework is finally applied to compute Rjb associated with PESMOS (474 records) and COSMOS (148 records) database and the results are expected to serve as a valuable resource while constructing GMPEs of shallow focused earthquakes.
Earthquake disasters are widespread in Indonesia, and one of the areas that frequently experiences earthquakes is Yogyakarta. Many buildings have experienced minor to severe damage during an earthquake. Given this reason, the building design should consider earthquake loads from spectral responses; however, there is the difficulty of getting time history data. In the latest earthquake map, the return period earthquake changes from the 475 to 2475 years made the old buildings comply with the new code. A research object that was selected in this study is the Alana Yogyakarta Hotel. This study examines the changes in time history's value based on shallow crustal earthquake sources using Probabilistic Seismic Hazard Analysis (PSHA). Earthquake events around Yogyakarta were collecting from various sources. In hazard analysis requires the distinction between the mainshock, foreshock, and aftershock. This study's attenuation function was selected based on the similarity of Indonesia's geological and tectonic conditions. A reference to select the time history data is the dominant distance and dominant magnitude from hazard deaggregation analysis. The spectral matching process was carried out to equalize the spectral response value in the study area of time history. The resulting time history is artificial. The results showed that the old code's peak acceleration value is smaller than in the new code.KeywordsShallow CrustalHazard deaggregationTime History
Recently developed region-specific GMPEs are used for a comprehensive seismic hazard analysis (SHA) of the North and Central Himalayas (NCH) using a probabilistic approach considering two source models. Vulnerable seismic sources in the areas are identified based on the Seismotectonic Atlas (Dasgupta et al. 2000), published by the Geological Survey of India. An up to date, homogenized and declustered earthquake catalogue is compiled from various sources, with earthquake data since 250 BC, to create a new digitized seismotectonic representation of the region. Regional seismic zones having similar seismicity are recognized based on the Gutenberg-Richter (GR) parameters and the region is delineated into 5 seismic zones. The study area is divided into grids of size 0.05° × 0.05° and the hazard in terms of Peak Ground Acceleration (PGA) at the centre of each grid point is estimated and presented as hazard maps for individual seismic sources, maximum of all sources, and average of both sources. From the current study, it could be concluded that the PGA estimated in the regions is comparatively higher than what is reported in the codal provisions for seismic zonation and estimation of design horizontal acceleration for the region.
Analisis hazard gempa untuk kota Jakarta dilakukan dengan menggunakan teori probabilitas total. Program
USGS-PSHA-07 digunakan untuk melakukan analisis hazard gempa dengan pemodelan sumber gempa 3-dimensi, untuk periode ulang 475 tahun. Hasil analisis menunjukkan bahwa percepatan maksimum batuan
dasar (PBA) di kota Jakarta (0.239 g) lebih besar dibanding PBA untuk kota Jakarta menurut SNI 03-1726-
2002 (0.15 g). Pembuatan ground motion sintetik dilakukan dengan bantuan Program SYNTH, dengan
menggunakan hasil deagregasi dari penelitian sebelumnya.
In practical building design, a time history is usually based on earthquake records from somewhere else, without any precise matching processes. Consequently, the time history is rarely used in building analysis, because of the difficulty in collecting accurate data at the building site. In this study, the site of the Alana Yogyakarta Hotel was selected as a research object for determining the real-time history, aimed towards an earthquake hazard analysis by using the Probabilistic Seismic Hazard Analysis (PSHA) method. Earthquake events affecting Yogyakarta and its surrounding areas were collected from earthquake catalogs and they were supplied from various sources, either from the government and/or from international institutions. The data that was used in the hazard analysis was focused on the main shock only, so the separation processes were essentially required to distinguish between the main shock, the foreshock and the aftershock. Due to the unavailability of attenuation functions, these were then determined based upon the earthquake data, by selecting the similarities of the tectonic and geological conditions in Indonesia, thus producing a seismic hazard curve and a uniform hazard response spectrum. The time history data on the bedrock was selected based on the dominant magnitude and the dominant distance of the subduction earthquakes and matched with the uniform hazard response spectrum, so as to produce a matched response spectrum. The results have shown that the peak times of the acceleration increased, as the results of the matching earthquake data on the bedrock corresponded to the hazard deaggregation analysis.
La reciente ocurrencia en España de terremotos de magnitud moderada próximos a zonas urbanas ha producido catastróficas consecuencias tanto a nivel social como económico. Una forma de estudiar medidas contra estos fenómenos naturales son los análisis de peligrosidad sísmica, concepto basado en la estimación de la frecuencia con la que una determinada amplitud del movimiento del suelo es excedida, durante un determinado período de tiempo, como consecuencia de la ocurrencia de terremotos. La actualización periódica de los mapas que representan la peligrosidad sísmica de España forma parte de una de las acciones más importantes que desarrolla el Instituto Geográfico Nacional en el marco de sus competencias en el campo de la sismología. El estudio que aquí se presenta es el resultado de un extenso proyecto iniciado en el año 2010 en el que han participado investigadores y técnicos de otras instituciones pertenecientes a los campos de la sismología, la ingeniería sísmica y la geología. La labor desarrollada por el grupo de trabajo interdisciplinar ha recogido las novedades en el conocimiento de la sismicidad regional de la península y en el avance de las técnicas para la elaboración de mapas de peligrosidad sísmica, junto con la información aportada por los recientes estudios sobre la actividad de fallas. Asimismo, el estudio se ha adecuado a la normativa europea, llevándose a cabo también una homogeneización con los países limítrofes.
Independientemente del aspecto científico del estudio, la cartografía sísmica obtenida tiene una
evidente componente de servicio público toda vez que sirve de base al mapa sísmico contenido en las
normas sismorresistentes de aplicación a los campos de la ingeniería y arquitectura en España y que
como consecuencia deberán asimismo actualizarse. De igual forma, el estudio recoge la puesta al día
del mapa incluido en la Directriz Básica de Protección Civil ante el Riesgo Sísmico, de indudable interés
a los efectos de planificación, tanto a nivel autonómico como a nivel local, cuya última modificación
fue aprobada por Acuerdo de Consejo de Ministros de 16 de julio de 2004 y publicada por Resolución de
la Subsecretaría de Interior de 17 de septiembre de 2004.
Hong Kong is located in a low- to moderate-seismicity region with earthquake damage to buildings having been recorded in the past. On average, there are about two earth tremors felt every year. Nowadays, the city is a unique place in the world with a high-density population living in high-rise buildings and surrounded by steeply sloping terrain. The potential risk of earthquake-induced damage thus calls for the development of a seismic design code for buildings in Hong Kong. In recent years, several critical geotechnical studies have been completed focusing on enhancing earthquake resilience in Hong Kong. They have included: (a) updating of probabilistic seismic hazard assessment based on a recent earthquake catalogue; (b) examination of local site effects and topographic amplification effects based on a pilot-area-specific seismic microzonation study; (c) reviewing the earthquake-induced landslide susceptibility of the natural terrain; and (d) assessment of the seismic stability of man-made slopes and retaining walls. These seismic studies are pivotal to the development of the seismic design code which is being pursued in Hong Kong. This paper is an important milestone in providing a detailed account of these studies and their impact on the code development.
This chapter describes different methodologies available for site characterization. The details of different low strain and high strain tests are also listed in this chapter. It also provides procedures for the evaluation of dynamic properties from the laboratory as well as in-situ tests. Further, this chapter also presents site characterization studies carried out at micro as well as macro-level.
Evidences from past earthquakes clearly show that the damages due to an earthquake and its severity at a site are controlled mainly by three factors, i.e., earthquake source and path characteristics, local geological and geotechnical characteristics, and structural design and quality of the construction. Seismic ground response at a site is strongly influenced by local geological and geotechnical conditions. The exact information of the geological, geomorphological, and geotechnical data along with seismotectonic details at a particular site are necessary to evaluate the ground response. The geometry of the subsoil structure, the soil type, the lateral discontinuities, and the surface topography will also influence the site response at a particular location. Since the seismic effects on the structure depend fully on the site conditions, research in the area of soil dynamics becomes more useful. The first input required in evaluation of geotechnical aspect of seismic hazard is the rock-level peak horizontal acceleration (PHA) values. The surface-level acceleration values need to be calculated based on the site conditions and site amplification values. This chapter discusses the recent advances in soil dynamics, especially in the area of geotechnical earthquake engineering. The topics covered in this chapter include various methods for evaluating the local site effects, dynamic soil properties, different field and laboratory tests required, various site classification schemes, and different methods to evaluate the surface-level ground motion. In addition to this, the aspects which need to be considered in liquefaction potential evaluation are also discussed.
Recently, large scale inland crustal earthquake have occurred frequently in Japan, and some of them have surface rupture. Existence of surface rupture significantly affects on ground motion characteristics, however, inland crustal earthquakes in Japan have been not previously analyzed except for the 1995 Kobe earthquake. In this study, we analyzed difference of ground motion characteristics between surface and buried rupture earthquakes in Japan. Ground motion characteristics were evaluated from deviations of observed response spectra with average response spectra calculated from a spectrum attenuation relationship. As a result, ground motion from buried rupture earthquake is two-times larger than those by surface rupture earthquake in frequency range between 0.1 and 0.4 seconds.
The contribution of remote sensing and geographical information system (GIS) techniques to estimate the surface level seismic hazard was investigated using topographic gradient maps in the states of Tripura and Mizoram. This paper addresses a vital issue on the estimation of the seismic hazards of Northeast (NE) India, where the hazards are high and the risk is also high. In developing site response maps or seismic hazard (surface acceleration) maps, it is difficult to obtain near-surface soil data (site-specific data) through geophysical/geotechnical field investigations at a smaller resolution scale (a state/region or country level). The topographic slope provides a reliable proxy because the rocky materials maintain a steep gradient/slope compared to soft soil deposits. In this paper, peak ground acceleration (PGA) at the bedrock for the states of Tripura and Mizoram in NE India has been estimated using probabilistic seismic hazard analysis (PSHA), which considers linear sources and events (from 1731 to 2010) with appropriate ground motion prediction equations applicable for NE India. Further, the authors have adopted the square root impedance model to estimate the spectral amplification of the study area to bring the hazard from bedrock level to surface. Authors have classified the entire study area as site classes B, C, and D categories and thereafter estimated spectral amplifications for the site periods (0.40, 0.21, 0.11, and 0.01 s). The surface level PGA (g) and amplification maps have been developed using a probabilistic approach considering PGA at the bedrock level. The results indicate that this area is highly sensitive to spectral responses, such as spectral acceleration or spectral amplification rather than PGA.
The site effect has been a polular topic in the field of earthquake engineering for a long time. Much effort has been made in studis on site effect by means of numerical simulation and theoretical computation. However, some methods based on strong-motion recordings are recently recognized and widely used, due to their simplicity and no need of many assumptions any more. In the 2008 Wenchuan earthquake, the China National Strong Motion Observation Network System (NSMONS) captured a large number of strong-motion recordings at free field both in the main shock and aftershocks. This makes a good chance for studying the site effect in the Wenchuan earthquake. In this paper, based on a database of these recordings, it takes a systematical study on the site classification, generalized inversion of site response and identification of nonlinearity of site response. That manages to extend the application of strong-motion recordings in the field of scientific research and engineering practice, and promote the development of strong-motion observation in China. The contents are summarized as follows:
(1) The merits and drawbacks of three common-used HVSR (Horizontal-to- Vertical Spectral Ratio) methods of site classification are summarized. Then an improved HVSR method using entropy weight theory is proposed. The site classes of 54 permanent stations and 66 temporary stations in the Wenchuan earthquake are classified by using these four methods. The comparisons between the results given by each method shows that the new method has a more scientific rationality.
(2) An updated classification criterion for six site classes is proposed and used in the process of site classification of temporary strong-motion stations in the Wenchuan earthquake. The results comfirms that it can raise the classification accuracy and effectively solve the problem that HVSR method can not be used for the sites where HVSR curves appear multiple peaks or no any peak. Finally, a preliminary analysis of the correlation between station elevation and its natural period TG identified by HVSR indicates that TG is generally smaller at higher elevations in Sichuan area.
(3) A total of 602 strong-motion recordings obtained by 28 stations from 96 aftershocks of the Wenchuan earthquake are selected as a dataset. The source, path and site effect of these recordings are separated by the generalized inversion technique (GIT). The inversion results have been verified as reliable by comparing the site response at station 62WUD using the GIT method and the the standard spectral ratio (SSR) method. For all 28 stations, the site predominant frequency Fp and the average site amplification in different frequency bands of 1.0-5.0 Hz, 5.0-10.0 Hz and 1.0-10.0 Hz are calculated based on the inversion results. Compared with the results from the HVSR method, it shows that the HVSR method can reasonably estimate the site predominant frequency but underestimates the site amplification. The linear fitting between the average site amplification for each frequency band and the Vs20 (the equivalent uppermost-20 m shear wave velocity) shows a good correlation.
(4) A distance measurement called the asperity distance DAsp is proposed to reasonably characterize the source-to-site distance for large earthquakes such as the Wenchuan earthquake, and is verified to be much better than the other three kinds of distance measurements, including the rupture distance (DRup), fault distance (DFau) and hypocentral distance (DHyp). Then it’s used for generalized inversion of site responses in the main shock of Wenchuan earthquake.
(5) The S transform is suggested to be used for identifying the nonlinearity of site seismic response. Combined with GIT method and HVSR method, it is practiced to identify the site responses of 33 strong-motion stations behave linearity or nonlinearity in the main shock of Wenchuan earthquake. The result shows that the site response appears obvious nonlinearity when PGA larger than 300 cm/s2 or PGV larger than 20 cm/s. In this regard, the sites of station 051AXT, 051GYS, 051GYZ, 051JYC, 051JYD, 051JYH, 051JZW, 051MXN, 051SFB and 062WUD also behave significant nonlinear responses. Compared with the results given by GIT method and HVSR method in the frequency domian, it is verified that the S transform can effectively identify the nonlinerity behavior of site seismic response in the time domain, and have an ablitity to determine the particular time when the nonlinearity occurs.
(6) The correlations between the ratio of Fp under weak motions and strong motion (RFp) and ground motion levels such as PGA and PGV, and site coefficients such as Vs20 and Vs30 are analyzed respectively. The results show RFp has a strongly positive correlation with PGA and PGV, but is uncorrelated with Vs20 and Vs30. A new definition called ADNL (absolute degree of nonlinearity) is proposed to characrize the degree of nonlinearity of site seismic response. Then the ADNL of each site and other parameters such as fNL (frequency of nonlinerity), DNL (degree of nonlinearity) and PNL (percentage of nonlinearity) are calculated. The empirical regression analysis between these parameters and PGA represents that each one has a strong correlation with PGA.
While the Southeast China region is situated in an intraplate area of low to moderate seismicity, it has experienced several noticeable earthquakes including the 1918 Shantou Earthquake having a magnitude of 7.3. This paper describes a rigorous probabilistic seismic hazard model for Southeast China using Hong Kong as a case study. Due to the scarcity of instrumental records of strong motion earthquakes, there are no appropriate ground motion predictive equations that can be derived from observed data. A number of the recently developed stochastic simulations of the seismological models have been appraised to quantify the seismic hazard as accurately as possible in order that future structures can be appropriately designed. As part of performing the hazard assessment, a detailed catalogue of historical and recent earthquakes within the Southeast China region has been compiled with data updated to 2009. A new seismic source model has also been developed based on consideration of observed seismicity, geological and tectonic information, and the source zone boundaries that were used to produce seismic hazard maps in the current Chinese code for seismic design of buildings, GB50011 (2010). The effect of the size of the seismic source zone is discussed. The results of the study include uniform seismic hazard spectra at the location of Hong Kong city and hazard maps for the surrounding part of Southeast China.
This manuscript examines the correlation of Arias intensity (AI) with nine amplitude-, duration-, and cumulative-based ground motion intensity measures. The correlations are determined using ground motions from active shallow crustal earthquakes in the NGA-West1 database, and recently developed ground motion prediction equations (GMPEs). Multiple GMPE combinations and bootstrap sampling are used to explicitly consider correlation uncertainties due to model selection and finite sample effects, respectively. It is shown that is highly correlated with high-frequency amplitude-based intensity measures and negatively correlated with significant duration intensity measures. also has a strong, but not perfect, correlation with cumulative absolute velocity ( ), which is also a cumulative measure of ground motion severity. Particular attention is given to the physical interpretation of the observed correlations of and other intensity measures, often in comparison to those obtained with . Parametric equations are developed to enable the obtained correlations to be easily used in applications such as ground motion selection and vector hazard analysis.
Resumen Este trabajo presenta un análisis de diferentes aspectos relacionados con el sismo principal del 11 de Mayo de 2011, con epicentro en las proximidades de Lorca, que abarcan desde el movimiento fuerte registrado hasta el daño observado en diferentes tipologías constructivas, contrastando todo ello con los resultados de estudios previos de peligrosidad y riesgo sísmico en la provincia de Murcia. La cuestión esencial que se plantea en el análisis es si tanto el movimiento como el daño entraban dentro de lo esperado o pueden considerarse anómalos en el marco del riesgo sísmico del sureste de España. A este respecto se hacen una serie de reflexiones y se extraen lecciones aprendidas del terremoto, que llevan a proponer recomendaciones de cara a la revisión de la Norma Sismorresisten-te Española, así como a definir medidas para la reducción del riesgo sísmico en la región. Palabras clave: peligrosidad sísmica, movimiento fuerte, riesgo sísmico, vulnerabilidad. Abstract An analysis of the different aspects related to the May 11th, 2011 Lorca earthquake is presented, covering recorded ground motions, damage observed in different building typologies, and contrasting these observations with previous results on seismic hazard and seismic risk obtained in the province of Murcia. The essential question addressed in the analysis is whether observed ground motions and physical damage can be considered as expected or as anomalous in the frame of seismic risk in southeastern Spain. In this respect, a number of reflections are carried out and several learned lessons from the earthquake are extracted, which leads to the proposal of different recommendations for the future revision of the Spanish earthquake-resistant provisions, as well as for defining risk reduction measurements in the region.
The NW and Central Himalayan region are seismically most active regions due to continued continent-continent collision between the Indian and the Eurasian plate and falls within the seismic zone IV and V of the seismic hazard zonation map of India. The probabilistic seismic hazard assessment for Himalayan region reported earlier was based on seismic catalogues, which were highly uncertain and incomplete because the modern instrumental seismicity data are available only after 1964. In this paper a new approach has been used to derive the mean annual rate of earthquake occurrence from the moment slip rate using the moment slip model.The study area and its adjoining region have been divided into twenty two seismic source zones based upon the geology, tectonics, and source mechanism relevant to the region. Annual rate of earthquake occurrence for each fault or source has been calculated using moment slip. In this work different global attenuation equations have been used for seismic hazard assessment. Standard procedure for PSHA has been adopted for this study and peak ground motion is estimated for 10% and 2% probability of exceedance in 50 years at the bedrock level. For the 10 % and 2 % probability of exceedance in 50 years, the PGA values vary from 0.1g to 0.45g and 0.18g to 0.75g respectively.Higher PGA values are observed in the southeast part region situated around Kaurik Fault System (KFS) and western parts of Nepal.
Until recently, the focus of FEMA’s Hazus earthquake model has been US centric, largely due to a lack of standardized building/infrastructure data formats applicable elsewhere. In a combined effort between FEMA Region 8 and the Universidad de Los Andes, Venezuela, the Hazus earthquake model was adapted to conduct earthquake loss estimations for Venezuela. The required population totals and demographic distributions were developed using Oak Ridge National Labs Landscan 2008 population data and the census 2001 data from the country. The accuracy of the model was further enhanced for Mérida State by the inclusion of geologic data maps and risk assessment data from other investigations. To identify possible scenarios we used a USGS ShakeMap scenario, representing the historical earthquake that occurred in Mérida in 1674 with an estimated magnitude Ms7.5. Countless minor seismic tremors are continually registered but there is an increasing probability of a damaging earthquake.
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