TY - JOUR A1 - Faenza, Licia A1 - Hainzl, Sebastian A1 - Scherbaum, Frank T1 - Statistical analysis of the Central-Europe seismicity N2 - The aim of this paper is to characterize the spatio-temporal distribution of Central-Europe seismicity. Specifically, by using a non-parametric statistical approach, the proportional hazard model, leading to an empirical estimation of the hazard function, we provide some constrains on the time behavior of earthquake generation mechanisms. The results indicate that the most conspicuous characteristics of M-w 4.0+ earthquakes is a temporal clustering lasting a couple of years. This suggests that the probability of occurrence increases immediately after a previous event. After a few years, the process becomes almost time independent. Furthermore, we investigate the cluster properties of the seismicity of Central-Europe, by comparing the obtained result with the one of synthetic catalogs generated by the epidemic type aftershock sequences (ETAS) model, which previously have been successfully applied for short term clustering. Our results indicate that the ETAS is not well suited to describe the seismicity as a whole, while it is able to capture the features of the short- term behaviour. Remarkably, similar results have been previously found for Italy using a higher magnitude threshold. Y1 - 2009 UR - http://www.sciencedirect.com/science/journal/00401951 U6 - https://doi.org/10.1016/j.tecto.2008.04.030 SN - 0040-1951 ER - TY - JOUR A1 - Ewald, Michael A1 - Igel, Heiner A1 - Hinzen, Klaus-Günther A1 - Scherbaum, Frank T1 - Basin-related effects on ground motion for earthquake scenarios in the Lower Rhine Embayment N2 - The deterministic calculation of earthquake scenarios using complete waveform modelling plays an increasingly important role in estimating shaking hazard in seismically active regions. Here we apply 3-D numerical modelling of seismic wave propagation to M 6+ earthquake scenarios in the area of the Lower Rhine Embayment, one of the seismically most active regions in central Europe. Using a 3-D basin model derived from geology, borehole information and seismic experiments, we aim at demonstrating the strong dependence of ground shaking on hypocentre location and basin structure. The simulations are carried out up to frequencies of ca. 1 Hz. As expected, the basin structure leads to strong lateral variations in peak ground motion, amplification and shaking duration. Depending on source-basin-receiver geometry, the effects correlate with basin depth and the slope of the basin flanks; yet, the basin also affects peak ground motion and estimated shaking hazard thereof outside the basin. Comparison with measured seismograms for one of the earthquakes shows that some of the main characteristics of the wave motion are reproduced. Cumulating the derived seismic intensities from the three modelled earthquake scenarios leads to a predominantly basin correlated intensity distribution for our study area Y1 - 2006 UR - http://onlinelibrary.wiley.com/journal/10.1111/(ISSN)1365-246X U6 - https://doi.org/10.1111/j.1365-246X.2006.02909.x SN - 0956-540X ER - TY - JOUR A1 - Esfahani, Reza Dokht Dolatabadi A1 - Vogel, Kristin A1 - Cotton, Fabrice A1 - Ohrnberger, Matthias A1 - Scherbaum, Frank A1 - Kriegerowski, Marius T1 - Exploring the dimensionality of ground-motion data by applying autoencoder techniques JF - Bulletin of the Seismological Society of America : BSSA N2 - In this article, we address the question of how observed ground-motion data can most effectively be modeled for engineering seismological purposes. Toward this goal, we use a data-driven method, based on a deep-learning autoencoder with a variable number of nodes in the bottleneck layer, to determine how many parameters are needed to reconstruct synthetic and observed ground-motion data in terms of their median values and scatter. The reconstruction error as a function of the number of nodes in the bottleneck is used as an indicator of the underlying dimensionality of ground-motion data, that is, the minimum number of predictor variables needed in a ground-motion model. Two synthetic and one observed datasets are studied to prove the performance of the proposed method. We find that mapping ground-motion data to a 2D manifold primarily captures magnitude and distance information and is suited for an approximate data reconstruction. The data reconstruction improves with an increasing number of bottleneck nodes of up to three and four, but it saturates if more nodes are added to the bottleneck. Y1 - 2021 U6 - https://doi.org/10.1785/0120200285 SN - 0037-1106 SN - 1943-3573 VL - 111 IS - 3 SP - 1563 EP - 1576 PB - Seismological Society of America CY - El Cerito, Calif. ER - TY - JOUR A1 - Douglas, John A1 - Bungum, Hilmar A1 - Scherbaum, Frank T1 - Ground-motion prediction equations for Southern Spain and Southern Norway obtained using the composite model perspective N2 - In this paper, two sets of earthquake ground-motion relations to estimate peak ground and response spectral acceleration are developed for sites in southern Spain and in southern Norway using a recently published composite approach. For this purpose seven empirical ground-motion relations developed from recorded strong-motion data from different parts of the world were employed. The different relations were first adjusted based on a number of transformations to convert the differing choices of independent parameters to a single one. After these transformations, which include the scatter introduced, were performed, the equations were modified to account for differences between the host and the target regions using the stochastic method to compute the host-to-target conversion factors. Finally functions were fitted to the derived ground-motion estimates to obtain sets of seven individual equations for use in probabilistic seismic hazard assessment for southern Spain and southern Norway. The relations are compared with local ones published for the two regions. The composite methodology calls for the setting up of independent logic trees for the median values and for the sigma values, in order to properly separate epistemic and aleatory uncertainties after the corrections and the conversions Y1 - 2006 UR - http://www.informaworld.com/openurl?genre=journal&issn=1363-2469 U6 - https://doi.org/10.1080/1363246060935058 SN - 1363-2469 ER - TY - JOUR A1 - Douglas, John A1 - Akkar, Sinan A1 - Ameri, Gabriele A1 - Bard, Pierre-Yves A1 - Bindi, Dino A1 - Bommer, Julian J. A1 - Bora, Sanjay Singh A1 - Cotton, Fabrice A1 - Derras, Boumediene A1 - Hermkes, Marcel A1 - Kuehn, Nicolas Martin A1 - Luzi, Lucia A1 - Massa, Marco A1 - Pacor, Francesca A1 - Riggelsen, Carsten A1 - Sandikkaya, M. Abdullah A1 - Scherbaum, Frank A1 - Stafford, Peter J. A1 - Traversa, Paola T1 - Comparisons among the five ground-motion models developed using RESORCE for the prediction of response spectral accelerations due to earthquakes in Europe and the Middle East JF - Bulletin of earthquake engineering : official publication of the European Association for Earthquake Engineering N2 - This article presents comparisons among the five ground-motion models described in other articles within this special issue, in terms of data selection criteria, characteristics of the models and predicted peak ground and response spectral accelerations. Comparisons are also made with predictions from the Next Generation Attenuation (NGA) models to which the models presented here have similarities (e.g. a common master database has been used) but also differences (e.g. some models in this issue are nonparametric). As a result of the differing data selection criteria and derivation techniques the predicted median ground motions show considerable differences (up to a factor of two for certain scenarios), particularly for magnitudes and distances close to or beyond the range of the available observations. The predicted influence of style-of-faulting shows much variation among models whereas site amplification factors are more similar, with peak amplification at around 1s. These differences are greater than those among predictions from the NGA models. The models for aleatory variability (sigma), however, are similar and suggest that ground-motion variability from this region is slightly higher than that predicted by the NGA models, based primarily on data from California and Taiwan. KW - Strong-motion data KW - Ground-motion models KW - Ground-motion prediction equations KW - Style of faulting KW - Site amplification KW - Aleatory variability KW - Epistemic uncertainty KW - Europe KW - Middle East Y1 - 2014 U6 - https://doi.org/10.1007/s10518-013-9522-8 SN - 1570-761X SN - 1573-1456 VL - 12 IS - 1 SP - 341 EP - 358 PB - Springer CY - Dordrecht ER - TY - JOUR A1 - Diallo, Mamadou Sanou A1 - Kulesh, Michail A1 - Holschneider, Matthias A1 - Scherbaum, Frank A1 - Adler, Frank T1 - Characterization of polarization attributes of seismic waves using continuous wavelet transforms N2 - Complex-trace analysis is the method of choice for analyzing polarized data. Because particle motion can be represented by instantaneous attributes that show distinct features for waves of different polarization characteristics, it can be used to separate and characterize these waves. Traditional methods of complex-trace analysis only give the instantaneous attributes as a function of time or frequency. However. for transient wave types or seismic events that overlap in time, an estimate of the polarization parameters requires analysis of the time-frequency dependence of these attributes. We propose a method to map instantaneous polarization attributes of seismic signals in the wavelet domain and explicitly relate these attributes with the wavelet-transform coefficients of the analyzed signal. We compare our method with traditional complex-trace analysis using numerical examples. An advantage of our method is its possibility of performing the complete wave-mode separation/ filtering process in the wavelet domain and its ability to provide the frequency dependence of ellipticity, which contains important information on the subsurface structure. Furthermore, using 2-C synthetic and real seismic shot gathers, we show how to use the method to separate different wave types and identify zones of interfering wave modes Y1 - 2006 UR - http://geophysics.geoscienceworld.org/ U6 - https://doi.org/10.1190/1.2194511 SN - 0016-8033 ER - TY - JOUR A1 - Diallo, Mamadou Sanou A1 - Kulesh, Michail A1 - Holschneider, Matthias A1 - Kurennaya, Kristina A1 - Scherbaum, Frank T1 - Instantaneous polarization attributes based on an adaptive approximate covariance method JF - Geophysics N2 - We introduce a method for computing instantaneous-polarization attributes from multicomponent signals. This is an improvement on the standard covariance method (SCM) because it does not depend on the window size used to compute the standard covariance matrix. We overcome the window-size problem by deriving an approximate analytical formula for the cross-energy matrix in which we automatically and adaptively determine the time window. The proposed method uses polarization analysis as applied to multicomponent seismic by waveform separation and filtering. Y1 - 2006 U6 - https://doi.org/10.1190/1.2227522 SN - 0016-8033 SN - 1942-2156 (0nline) VL - 71 IS - 5 SP - V99 EP - V104 PB - SEG CY - Tulsa ER - TY - JOUR A1 - Delavaud, Elise A1 - Scherbaum, Frank A1 - Kühn, Nicolas A1 - Allen, Trevor T1 - Testing the global applicability of ground-motion prediction equations for active shallow crustal regions JF - Bulletin of the Seismological Society of America N2 - Large research initiatives such as the Global Earthquake Model (GEM) or the Seismic HAzard haRmonization in Europe (SHARE) projects concentrate a great collaborative effort on defining a global standard for seismic hazard estimations. In this context, there is an increasing need for identifying ground-motion prediction equations (GMPEs) that can be applied at both global and regional scale. With increasing amounts of strong-motion records that are now available worldwide, observational data can provide a valuable resource to tackle this question. Using the global dataset of Allen and Wald (2009), we evaluate the ability of 11 GMPEs to predict ground-motion in different active shallow crustal regions worldwide. Adopting the approach of Scherbaum et al. (2009), we rank these GMPEs according to their likelihood of having generated the data. In particular, we estimate how strongly data support or reject the models with respect to the state of noninformativeness defined by a uniform weighting. Such rankings derived from this particular global dataset enable us to explore the potential of GMPEs to predict ground motions in their host region and also in other regions depending on the magnitude and distance considered. In the ranking process, we particularly focus on the influence of the distribution of the testing dataset compared with the GMPE's native dataset. One of the results of this study is that some nonindigenous models present a high degree of consistency with the data from a target region. Two models in particular demonstrated a strong power of geographically wide applicability in different geographic regions with respect to the testing dataset: the models of Akkar and Bommer (2010) and Chiou et al. (2010). Y1 - 2012 U6 - https://doi.org/10.1785/0120110113 SN - 0037-1106 VL - 102 IS - 2 SP - 707 EP - 721 PB - Seismological Society of America CY - El Cerrito ER - TY - JOUR A1 - Delavaud, Elise A1 - Scherbaum, Frank A1 - Kuehn, Nicolas A1 - Riggelsen, Carsten T1 - Information-theoretic selection of ground-motion prediction equations for seismic hazard analysis : an applicability study using Californian data N2 - Considering the increasing number and complexity of ground-motion prediction equations available for seismic hazard assessment, there is a definite need for an efficient, quantitative, and robust method to select and rank these models for a particular region of interest. In a recent article, Scherbaum et al. (2009) have suggested an information- theoretic approach for this purpose that overcomes several shortcomings of earlier attempts at using data-driven ground- motion prediction equation selection procedures. The results of their theoretical study provides evidence that in addition to observed response spectra, macroseismic intensity data might be useful for model selection and ranking. We present here an applicability study for this approach using response spectra and macroseismic intensities from eight Californian earthquakes. A total of 17 ground-motion prediction equations, from different regions, for response spectra, combined with the equation of Atkinson and Kaka (2007) for macroseismic intensities are tested for their relative performance. The resulting data-driven rankings show that the models that best estimate ground motion in California are, as one would expect, Californian and western U. S. models, while some European models also perform fairly well. Moreover, the model performance appears to be strongly dependent on both distance and frequency. The relative information of intensity versus response spectral data is also explored. The strong correlation we obtain between intensity-based rankings and spectral-based ones demonstrates the great potential of macroseismic intensities data for model selection in the context of seismic hazard assessment. Y1 - 2009 UR - http://bssa.geoscienceworld.org/ U6 - https://doi.org/10.1785/0120090055 SN - 0037-1106 ER - TY - JOUR A1 - Delavaud, Elise A1 - Cotton, Fabrice A1 - Akkar, Sinan A1 - Scherbaum, Frank A1 - Danciu, Laurentiu A1 - Beauval, Celine A1 - Drouet, Stephane A1 - Douglas, John A1 - Basili, Roberto A1 - Sandikkaya, M. Abdullah A1 - Segou, Margaret A1 - Faccioli, Ezio A1 - Theodoulidis, Nikos T1 - Toward a ground-motion logic tree for probabilistic seismic hazard assessment in Europe JF - Journal of seismology N2 - The Seismic Hazard Harmonization in Europe (SHARE) project, which began in June 2009, aims at establishing new standards for probabilistic seismic hazard assessment in the Euro-Mediterranean region. In this context, a logic tree for ground-motion prediction in Europe has been constructed. Ground-motion prediction equations (GMPEs) and weights have been determined so that the logic tree captures epistemic uncertainty in ground-motion prediction for six different tectonic regimes in Europe. Here we present the strategy that we adopted to build such a logic tree. This strategy has the particularity of combining two complementary and independent approaches: expert judgment and data testing. A set of six experts was asked to weight pre-selected GMPEs while the ability of these GMPEs to predict available data was evaluated with the method of Scherbaum et al. (Bull Seismol Soc Am 99:3234-3247, 2009). Results of both approaches were taken into account to commonly select the smallest set of GMPEs to capture the uncertainty in ground-motion prediction in Europe. For stable continental regions, two models, both from eastern North America, have been selected for shields, and three GMPEs from active shallow crustal regions have been added for continental crust. For subduction zones, four models, all non-European, have been chosen. Finally, for active shallow crustal regions, we selected four models, each of them from a different host region but only two of them were kept for long periods. In most cases, a common agreement has been also reached for the weights. In case of divergence, a sensitivity analysis of the weights on the seismic hazard has been conducted, showing that once the GMPEs have been selected, the associated set of weights has a smaller influence on the hazard. KW - Logic trees KW - Ground-motion prediction equations KW - Expert judgment KW - Model selection KW - Seismic hazard assessment Y1 - 2012 U6 - https://doi.org/10.1007/s10950-012-9281-z SN - 1383-4649 VL - 16 IS - 3 SP - 451 EP - 473 PB - Springer CY - Dordrecht ER - TY - JOUR A1 - Deichmann, N. A1 - Ansorge, Jörg A1 - Scherbaum, Frank A1 - Aschwanden, Andy A1 - Bernadi, F. A1 - Gudmundsson, Gudmundur Hilmar T1 - Evidence for deep icequakes in an alpine glacier Y1 - 1999 ER - TY - JOUR A1 - Dahm, Torsten A1 - Kuehn, Daniela A1 - Ohrnberger, Matthias A1 - Kroeger, Jens A1 - Wiederhold, Helga A1 - Reuther, Claus-Dieter A1 - Dehghani, Ali A1 - Scherbaum, Frank T1 - Combining geophysical data sets to study the dynamics of shallow evaporites in urban environments : application to Hamburg, Germany N2 - Shallowly situated evaporites in built-up areas are of relevance for urban and cultural development and hydrological regulation. The hazard of sinkholes, subrosion depressions and gypsum karst is often difficult to evaluate and may quickly change with anthropogenic influence. The geophysical exploration of evaporites in metropolitan areas is often not feasible with active industrial techniques. We collect and combine different passive geophysical data as microgravity, ambient vibrations, deformation and hydrological information to study the roof morphology of shallow evaporites beneath Hamburg, Northern Germany. The application of a novel gravity inversion technique leads to a 3-D depth model of the salt diapir under study. We compare the gravity-based depth model to pseudo-depths from H/V measurements and depth estimates from small-scale seismological array data. While the general range and trend of the diapir roof is consistent, a few anomalous regions are identified where H/V pseudo-depths indicate shallower structures not observed in gravity or array data. These are interpreted by shallow residual caprock floaters and zones of increased porosity. The shallow salt structure clearly correlates with a relative subsidence in the order of 2 mm yr(-1). The combined interpretation of roof morphology, yearly subsidence rates, chemical analyses of groundwater and of hydraulic head in aquifers indicates that the salt diapir beneath Hamburg is subject to significant ongoing dissolution that may possibly affect subrosion depressions, sinkhole distribution and land usage. The combined analysis of passive geophysical data may be exemplary for the study of shallow evaporites beneath other urban areas. Y1 - 2010 UR - http://onlinelibrary.wiley.com/journal/10.1111/(ISSN)1365-246X U6 - https://doi.org/10.1111/j.1365-246X.2010.04521.x SN - 0956-540X ER - TY - JOUR A1 - Bora, Sanjay Singh A1 - Scherbaum, Frank A1 - Kühn, Nicolas A1 - Stafford, Peter A1 - Edwards, Benjamin T1 - Development of a Response Spectral Ground-Motion Prediction Equation (GMPE) for Seismic-Hazard Analysis from Empirical Fourier Spectral and Duration Models JF - Bulletin of the Seismological Society of America N2 - Empirical ground-motion prediction equations (GMPEs) require adjustment to make them appropriate for site-specific scenarios. However, the process of making such adjustments remains a challenge. This article presents a holistic framework for the development of a response spectral GMPE that is easily adjustable to different seismological conditions and does not suffer from the practical problems associated with adjustments in the response spectral domain. The approach for developing a response spectral GMPE is unique, because it combines the predictions of empirical models for the two model components that characterize the spectral and temporal behavior of the ground motion. Essentially, as described in its initial form by Bora et al. (2014), the approach consists of an empirical model for the Fourier amplitude spectrum (FAS) and a model for the ground-motion duration. These two components are combined within the random vibration theory framework to obtain predictions of response spectral ordinates. In addition, FAS corresponding to individual acceleration records are extrapolated beyond the useable frequencies using the stochastic FAS model, obtained by inversion as described in Edwards and Fah (2013a). To that end, a (oscillator) frequency-dependent duration model, consistent with the empirical FAS model, is also derived. This makes it possible to generate a response spectral model that is easily adjustable to different sets of seismological parameters, such as the stress parameter Delta sigma, quality factor Q, and kappa kappa(0). The dataset used in Bora et al. (2014), a subset of the RESORCE-2012 database, is considered for the present analysis. Based upon the range of the predictor variables in the selected dataset, the present response spectral GMPE should be considered applicable over the magnitude range of 4 <= M-w <= 7.6 at distances <= 200 km. Y1 - 2015 U6 - https://doi.org/10.1785/0120140297 SN - 0037-1106 SN - 1943-3573 VL - 105 IS - 4 SP - 2192 EP - 2218 PB - Seismological Society of America CY - Albany ER - TY - JOUR A1 - Bora, Sanjay Singh A1 - Scherbaum, Frank A1 - Kuehn, Nicolas A1 - Stafford, Peter T1 - On the Relationship between Fourier and Response Spectra: Implications for the Adjustment of Empirical Ground-Motion Prediction Equations (GMPEs) JF - Bulletin of the Seismological Society of America N2 - The functional form of empirical response spectral ground-motion prediction equations (GMPEs) is often derived using concepts borrowed from Fourier spectral modeling of ground motion. As these GMPEs are subsequently calibrated with empirical observations, this may not appear to pose any major problems in the prediction of ground motion for a particular earthquake scenario. However, the assumption that Fourier spectral concepts persist for response spectra can lead to undesirable consequences when it comes to the adjustment of response spectral GMPEs to represent conditions not covered in the original empirical data set. In this context, a couple of important questions arise, for example, what are the distinctions and/or similarities between Fourier and response spectra of ground motions? And, if they are different, then what is the mechanism responsible for such differences and how do adjustments that are made to Fourier amplitude spectrum (FAS) manifest in response spectra? The present article explores the relationship between the Fourier and response spectrum of ground motion by using random vibration theory (RVT). With a simple Brune (1970, 1971) source model, RVT-generated acceleration spectra for a fixed magnitude and distance scenario are used. The RVT analyses reveal that the scaling of low oscillator-frequency response spectral ordinates can be treated as being equivalent to the scaling of the corresponding Fourier spectral ordinates. However, the high oscillator-frequency response spectral ordinates are controlled by a rather wide band of Fourier spectral ordinates. In fact, the peak ground acceleration, counter to the popular perception that it is a reflection of the high-frequency characteristics of ground motion, is controlled by the entire Fourier spectrum of ground motion. Additionally, this article demonstrates how an adjustment made to FAS is similar or different to the same adjustment made to response spectral ordinates. For this purpose, two cases: adjustments to the stress parameter (Delta sigma) (source term), and adjustments to the attributes reflecting site response (V-S - kappa(0)) are considered. Y1 - 2016 U6 - https://doi.org/10.1785/0120150129 SN - 0037-1106 SN - 1943-3573 VL - 106 SP - 1235 EP - 1253 PB - Seismological Society of America CY - Albany ER - TY - JOUR A1 - Bora, Sanjay Singh A1 - Cotton, Fabrice A1 - Scherbaum, Frank A1 - Edwards, Benjamin A1 - Traversa, Paola T1 - Stochastic source, path and site attenuation parameters and associated variabilities for shallow crustal European earthquakes JF - Bulletin of earthquake engineering : official publication of the European Association for Earthquake Engineering N2 - We have analyzed the recently developed pan-European strong motion database, RESORCE-2012: spectral parameters, such as stress drop (stress parameter, Delta sigma), anelastic attenuation (Q), near surface attenuation (kappa(0)) and site amplification have been estimated from observed strong motion recordings. The selected dataset exhibits a bilinear distance-dependent Q model with average kappa(0) value 0.0308 s. Strong regional variations in inelastic attenuation were also observed: frequency-independent Q(0) of 1462 and 601 were estimated for Turkish and Italian data respectively. Due to the strong coupling between Q and kappa(0), the regional variations in Q have strong impact on the estimation of near surface attenuation kappa(0). kappa(0) was estimated as 0.0457 and 0.0261 s for Turkey and Italy respectively. Furthermore, a detailed analysis of the variability in estimated kappa(0) revealed significant within-station variability. The linear site amplification factors were constrained from residual analysis at each station and site-class type. Using the regional Q(0) model and a site-class specific kappa(0), seismic moments (M-0) and source corner frequencies f (c) were estimated from the site corrected empirical Fourier spectra. Delta sigma did not exhibit magnitude dependence. The median Delta sigma value was obtained as 5.75 and 5.65 MPa from inverted and database magnitudes respectively. A comparison of response spectra from the stochastic model (derived herein) with that from (regional) ground motion prediction equations (GMPEs) suggests that the presented seismological parameters can be used to represent the corresponding seismological attributes of the regional GMPEs in a host-to-target adjustment framework. The analysis presented herein can be considered as an update of that undertaken for the previous Euro-Mediterranean strong motion database presented by Edwards and Fah (Geophys J Int 194(2):1190-1202, 2013a). KW - Stochastic model KW - Attenuation KW - Stress parameter KW - Kappa KW - Crustal earthquakes Y1 - 2017 U6 - https://doi.org/10.1007/s10518-017-0167-x SN - 1570-761X SN - 1573-1456 VL - 15 SP - 4531 EP - 4561 PB - Springer CY - Dordrecht ER - TY - JOUR A1 - Bora, Sanjay Singh A1 - Cotton, Fabrice A1 - Scherbaum, Frank T1 - NGA-West2 Empirical Fourier and Duration Models to Generate Adjustable Response Spectra JF - Earthquake spectra : the professional journal of the Earthquake Engineering Research Institute N2 - Adjustment of median ground motion prediction equations (GMPEs) from one region to another region is one of the major challenges within the current practice of seismic hazard analysis. In our approach of generating response spectra, we derive two separate empirical models for a) Fourier amplitude spectrum (FAS) and b) duration of ground motion. To calculate response spectra, the two models are combined within the random vibration theory (RVT) framework. The models are calibrated on recordings obtained from shallow crustal earthquakes in active tectonic regions. We use a subset of NGA-West2 database with M3.2-7.9 earthquakes at distances 0-300 km. The NGA-West2 database expanded over a wide magnitude and distance range facilitates a better constraint over derived models. A frequency-dependent duration model is derived to obtain adjustable response spectral ordinates. Excellent comparison of our approach with other NGA-West2 models implies that it can also be used as a stand-alone model. Y1 - 2019 U6 - https://doi.org/10.1193/110317EQS228M SN - 8755-2930 SN - 1944-8201 VL - 35 IS - 1 SP - 61 EP - 93 PB - Sage Publ. CY - Thousand Oaks ER - TY - JOUR A1 - Bommer, Julian J. A1 - Scherbaum, Frank A1 - Bungum, Hilmar A1 - Cotton, Fabrice A1 - Sabetta, F. A1 - Abrahamson, Norman A. T1 - On the use of logic trees for ground-motion prediction equations in seismic-hazard analysis N2 - Logic trees are widely used in probabilistic seismic hazard analysis as a tool to capture the epistemic uncertainty associated with the seismogenic sources and the ground-motion prediction models used in estimating the hazard. Combining two or more ground-motion relations within a logic tree will generally require several conversions to be made, because there are several definitions available for both the predicted ground-motion parameters and the explanatory parameters within the predictive ground-motion relations. Procedures for making conversions for each of these factors are presented, using a suite of predictive equations in current use for illustration. The sensitivity of the resulting ground-motion models to these conversions is shown to be pronounced for some of the parameters, especially the measure of source-to-site distance, highlighting the need to take into account any incompatibilities among the selected equations. Procedures are also presented for assigning weights to the branches in the ground-motion section of the logic tree in a transparent fashion, considering both intrinsic merits of the individual equations and their degree of applicability to the particular application Y1 - 2005 SN - 0037-1106 ER - TY - JOUR A1 - Bommer, Julian J. A1 - Douglas, John A1 - Scherbaum, Frank A1 - Cotton, Fabrice A1 - Bungum, Hilmar A1 - Faeh, Donat T1 - On the selection of ground-motion prediction equations for seismic hazard analysis Y1 - 2010 UR - http://srl.geoscienceworld.org/ U6 - https://doi.org/10.1785/gssrl.81.5.783 SN - 0895-0695 ER - TY - JOUR A1 - Bommer, Julian J. A1 - Coppersmith, Kevin J. A1 - Coppersmith, Ryan T. A1 - Hanson, Kathryn L. A1 - Mangongolo, Azangi A1 - Neveling, Johann A1 - Rathje, Ellen M. A1 - Rodriguez-Marek, Adrian A1 - Scherbaum, Frank A1 - Shelembe, Refilwe A1 - Stafford, Peter J. A1 - Strasser, Fleur O. T1 - A SSHAC Level 3 Probabilistic Seismic Hazard Analysis for a New-Build Nuclear Site in South Africa JF - Earthquake spectra : the professional journal of the Earthquake Engineering Research Institute N2 - A probabilistic seismic hazard analysis has been conducted for a potential nuclear power plant site on the coast of South Africa, a country of low-to-moderate seismicity. The hazard study was conducted as a SSHAC Level 3 process, the first application of this approach outside North America. Extensive geological investigations identified five fault sources with a non-zero probability of being seismogenic. Five area sources were defined for distributed seismicity, the least active being the host zone for which the low recurrence rates for earthquakes were substantiated through investigations of historical seismicity. Empirical ground-motion prediction equations were adjusted to a horizon within the bedrock at the site using kappa values inferred from weak-motion analyses. These adjusted models were then scaled to create new equations capturing the range of epistemic uncertainty in this region with no strong motion recordings. Surface motions were obtained by convolving the bedrock motions with site amplification functions calculated using measured shear-wave velocity profiles. Y1 - 2015 U6 - https://doi.org/10.1193/060913EQS145M SN - 8755-2930 SN - 1944-8201 VL - 31 IS - 2 SP - 661 EP - 698 PB - Earthquake Engineering Research Institute CY - Oakland ER - TY - JOUR A1 - Bommer, Julian J. A1 - Abrahamson, Norman A. A1 - Strasser, F. O. A1 - Pecker, Alain A1 - Bard, Pierre-Yves A1 - Bungum, Hilmar A1 - Cotton, Fabrice A1 - Fäh, Donat A1 - Sabetta, F. A1 - Scherbaum, Frank A1 - Studer, Jost T1 - The challenge of defining upper bounds on earthquake ground motions Y1 - 2004 SN - 0895-0695 ER - TY - JOUR A1 - Blaser, Lilian A1 - Ohrnberger, Matthias A1 - Krüger, Frank A1 - Scherbaum, Frank T1 - Probabilistic tsunami threat assessment of 10 recent earthquakes offshore Sumatra JF - Geophysical journal international N2 - Tsunami early warning (TEW) is a challenging task as a decision has to be made within few minutes on the basis of incomplete and error-prone data. Deterministic warning systems have difficulties in integrating and quantifying the intrinsic uncertainties. In contrast, probabilistic approaches provide a framework that handles uncertainties in a natural way. Recently, we have proposed a method using Bayesian networks (BNs) that takes into account the uncertainties of seismic source parameter estimates in TEW. In this follow-up study, the method is applied to 10 recent large earthquakes offshore Sumatra and tested for its performance. We have evaluated both the general model performance given the best knowledge we have today about the source parameters of the 10 events and the corresponding response on seismic source information evaluated in real-time. We find that the resulting site-specific warning level probabilities represent well the available tsunami wave measurements and observations. Difficulties occur in the real-time tsunami assessment if the moment magnitude estimate is severely over- or underestimated. In general, the probabilistic analysis reveals a considerably large range of uncertainties in the near-field TEW. By quantifying the uncertainties the BN analysis provides important additional information to a decision maker in a warning centre to deal with the complexity in TEW and to reason under uncertainty. KW - Probabilistic forecasting KW - Tsunamis KW - Early warning KW - Indian Ocean Y1 - 2012 U6 - https://doi.org/10.1111/j.1365-246X.2011.05324.x SN - 0956-540X VL - 188 IS - 3 SP - 1273 EP - 1284 PB - Wiley-Blackwell CY - Malden ER - TY - JOUR A1 - Blaser, Lilian A1 - Krüger, Frank A1 - Ohrnberger, Matthias A1 - Scherbaum, Frank T1 - Scaling relations of earthquake source parameter estimates with special focus on subduction environment N2 - Earthquake rupture length and width estimates are in demand in many seismological applications. Earthquake magnitude estimates are often available, whereas the geometrical extensions of the rupture fault mostly are lacking. Therefore, scaling relations are needed to derive length and width from magnitude. Most frequently used are the relationships of Wells and Coppersmith (1994) derived on the basis of a large dataset including all slip types with the exception of thrust faulting events in subduction environments. However, there are many applications dealing with earthquakes in subduction zones because of their high seismic and tsunamigenic potential. There are no well-established scaling relations for moment magnitude and length/width for subduction events. Within this study, we compiled a large database of source parameter estimates of 283 earthquakes. All focal mechanisms are represented, but special focus is set on (large) subduction zone events, in particular. Scaling relations were fitted with linear least-square as well as orthogonal regression and analyzed regarding the difference between continental and subduction zone/oceanic relationships. Additionally, the effect of technical progress in earthquake parameter estimation on scaling relations was tested as well as the influence of different fault mechanisms. For a given moment magnitude we found shorter but wider rupture areas of thrust events compared to Wells and Coppersmith (1994). The thrust event relationships for pure continental and pure subduction zone rupture areas were found to be almost identical. The scaling relations differ significantly for slip types. The exclusion of events prior to 1964 when the worldwide standard seismic network was established resulted in a remarkable effect on strike-slip scaling relations: the data do not show any saturation of rupture width of strike- slip earthquakes. Generally, rupture area seems to scale with mean slip independent of magnitude. The aspect ratio L/W, however, depends on moment and differs for each slip type. Y1 - 2010 UR - http://bssa.geoscienceworld.org/ U6 - https://doi.org/10.1785/0120100111 SN - 0037-1106 ER - TY - JOUR A1 - Beauval, Céline A1 - Hainzl, Sebastian A1 - Scherbaum, Frank T1 - Probabilistic seismic hazard estimation in low-seismicity regions considering non-Poissonian seismic occurrence N2 - In low-seismicity regions, such as France or Germany, the estimation of probabilistic seismic hazard must cope with the difficult identification of active faults and with the low amount of seismic data available. Since the probabilistic hazard method was initiated, most studies assume a Poissonian occurrence of earthquakes. Here we propose a method that enables the inclusion of time and space dependences between earthquakes into the probabilistic estimation of hazard. Combining the seismicity model Epidemic Type Aftershocks-Sequence (ETAS) with a Monte Carlo technique, aftershocks are naturally accounted for in the hazard determination. The method is applied to the Pyrenees region in Southern France. The impact on hazard of declustering and of the usual assumption that earthquakes occur according to a Poisson process is quantified, showing that aftershocks contribute on average less than 5 per cent to the probabilistic hazard, with an upper bound around 18 per cent Y1 - 2006 UR - http://onlinelibrary.wiley.com/journal/10.1111/(ISSN)1365-246X U6 - https://doi.org/10.1111/j.1365-246X.2006.02863.x SN - 0956-540X ER - TY - JOUR A1 - Beauval, Celine A1 - Hainzl, Sebastian A1 - Scherbaum, Frank T1 - The impact of the spatial uniform distribution of seismicity on probabilistic seismic-hazard estimation JF - Bulletin of the Seismological Society of America N2 - The first step in the estimation of probabilistic seismic hazard in a region commonly consists of the definition and characterization of the relevant seismic sources. Because in low-seismicity regions seismicity is often rather diffuse and faults are difficult to identify, large areal source zones are mostly used. The corresponding hypothesis is that seismicity is uniformly distributed inside each areal seismic source zone. In this study, the impact of this hypothesis on the probabilistic hazard estimation is quantified through the generation of synthetic spatial seismicity distributions. Fractal seismicity distributions are generated inside a given source zone and probabilistic hazard is computed for a set of sites located inside this zone. In our study, the impact of the spatial seismicity distribution is defined as the deviation from the hazard value obtained for a spatially uniform seismicity distribution. From the generation of a large number of synthetic distributions, the correlation between the fractal dimension D and the impact is derived. The results show that the assumption of spatially uniform seismicity tends to bias the hazard to higher values. The correlation can be used to determine the systematic biases and uncertainties for hazard estimations in real cases, where the fractal dimension has been determined. We apply the technique in Germany (Cologne area) and in France (Alps). Y1 - 2006 U6 - https://doi.org/10.1785/0120060073 SN - 0037-1106 VL - 96 IS - 6 SP - 2465 EP - 2471 PB - GeoScienceWorld CY - Alexandria, Va. ER - TY - JOUR A1 - Al Atik, Linda A1 - Abrahamson, Norman A. A1 - Bommer, Julian J. A1 - Scherbaum, Frank A1 - Cotton, Fabrice A1 - Kuehn, Nicolas T1 - The variability of ground-motion prediction models and its components Y1 - 2010 UR - http://srl.geoscienceworld.org/ U6 - https://doi.org/10.1785/gssrl.81.5.794 SN - 0895-0695 ER -