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 - 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 - Kulesh, Michail A1 - Holschneider, Matthias A1 - Diallo, Mamadou Sanou A1 - Xie, Q. A1 - Scherbaum, Frank T1 - Modeling of wave dispersion using continuous wavelet transforms N2 - In the estimate of dispersion with the help of wavelet analysis considerable emphasis has been put on the extraction of the group velocity using the modulus of the wavelet transform. In this paper we give an asymptotic expression of the full propagator in wavelet space that comprises the phase velocity as well. This operator establishes a relationship between the observed signals at two different stations during wave propagation in a dispersive and attenuating medium. Numerical and experimental examples are presented to show that the method accurately models seismic wave dispersion and attenuation Y1 - 2005 SN - 0033-4553 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 - 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 - Schmedes, J. A1 - Hainzl, Sebastian A1 - Reamer, S. K. A1 - Scherbaum, Frank A1 - Hinzen, K. G. T1 - Moment release in the Lower Rhine Embayment, Germany : seismological perspective of the deformation process N2 - An important task of seismic hazard assessment consists of estimating the rate of seismic moment release which is correlated to the rate of tectonic deformation and the seismic coupling. However, the estimations of deformation depend on the type of information utilized (e.g. geodetic, geological, seismic) and include large uncertainties. We therefore estimate the deformation rate in the Lower Rhine Embayment (LRE), Germany, using an integrated approach where the uncertainties have been systematically incorporated. On the basis of a new homogeneous earthquake catalogue we initially determine the frequency-magnitude distribution by statistical methods. In particular, we focus on an adequate estimation of the upper bound of the Gutenberg-Richter relation and demonstrate the importance of additional palaeoseis- mological information. The integration of seismological and geological information yields a probability distribution of the upper bound magnitude. Using this distribution together with the distribution of Gutenberg-Richter a and b values, we perform Monte Carlo simulations to derive the seismic moment release as a function of the observation time. The seismic moment release estimated from synthetic earthquake catalogues with short catalogue length is found to systematically underestimate the long-term moment rate which can be analytically determined. The moment release recorded in the LRE over the last 250 yr is found to be in good agreement with the probability distribution resulting from the Monte Carlo simulations. Furthermore, the long-term distribution is within its uncertainties consistent with the moment rate derived by geological measurements, indicating an almost complete seismic coupling in this region. By means of Kostrov's formula, we additionally calculate the full deformation rate tensor using the distribution of known focal mechanisms in LRE. Finally, we use the same approach to calculate the seismic moment and the deformation rate for two subsets of the catalogue corresponding to the east- and west-dipping faults, respectively Y1 - 2005 SN - 0956-540X ER - TY - JOUR A1 - Hainzl, Sebastian A1 - Scherbaum, Frank A1 - Beauval, Céline T1 - Estimating background activity based on interevent-time distribution N2 - The statistics of time delays between successive earthquakes has recently been claimed to be universal and to show the existence of clustering beyond the duration of aftershock bursts. We demonstrate that these claims are unjustified. Stochastic simulations with Poissonian background activity and triggered Omori-type aftershock sequences are shown to reproduce the interevent-time distributions observed on different spatial and magnitude scales in California. Thus the empirical distribution can be explained without any additional long-term clustering. Furthermore, we find that the shape of the interevent-time distribution, which can be approximated by the gamma distribution, is determined by the percentage of main-shocks in the catalog. This percentage can be calculated by the mean and variance of the interevent times and varies between 5% and 90% for different regions in California. Our investigation of stochastic simulations indicates that the interevent-time distribution provides a nonparametric reconstruction of the mainshock magnitude-frequency distribution that is superior to standard declustering algorithm Y1 - 2006 UR - http://bssa.geoscienceworld.org/ U6 - https://doi.org/10.1785/0120050053 SN - 0037-1106 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 - 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 - Kohler, A. A1 - Ohrnberger, Matthias A1 - Scherbaum, Frank A1 - Stange, S. A1 - Kind, F. T1 - Ambient vibration measurements in the Southern Rhine Graben close to Basle N2 - This study presents results of ambient noise measurements from temporary single station and small-scale array deployments in the northeast of Basle. H/V spectral ratios were determined along various profiles crossing the eastern masterfault of the Rhine Rift Valley and the adjacent sedimentary rift fills. The fundamental H/V peak frequencies are decreasing along the profile towards the eastern direction being consistent with the dip of the tertiary sediments within the rift. Using existing empirical relationships between H/V frequency peaks and the depth of the dominant seismic contrast, derived on basis of the lambda/4-resonance hypothesis and a power law depth dependence of the S-wave velocity, we obtain thicknesses of the rift fill from about 155 m in the west to 280 in in the east. This is in agreement with previous studies. The array analysis of the ambient noise wavefield yielded a stable dispersion relation consistent with Rayleigh wave propagation velocities. We conclude that a significant amount of surface waves is contained in the observed wavefield. The computed ellipticity for fundamental mode Rayleigh waves for the velocity depth models used for the estimation of the sediment thicknesses is in agreement with the observed H/V spectra over a large frequency band Y1 - 2004 SN - 1593-5213 ER - TY - JOUR A1 - Kummerow, J. A1 - Kind, Rainer A1 - Oncken, Onno A1 - Giese, Peter A1 - Ryberg, Trond A1 - Wylegalla, Kurt A1 - Scherbaum, Frank T1 - A natural and controlled source seismic profile through the Eastern Alps : TRANSALP N2 - The combined passive and active seismic TRANSALP experiment produced an unprecedented high-resolution crustal image of the Eastern Alps between Munich and Venice. The European and Adriatic Mohos (EM and AM, respectively) are clearly imaged with different seismic techniques: near-vertical incidence reflections and receiver functions (RFs). The European Moho dips gently southward from 35 km beneath the northern foreland to a maximum depth of 55 km beneath the central part of the Eastern Alps, whereas the Adriatic Moho is imaged primarily by receiver functions at a relatively constant depth of about 40 km. In both data sets, we have also detected first-order Alpine shear zones, such as the Helvetic detachment, Inntal fault and SubTauern ramp in the north. Apart from the Valsugana thrust, receiver functions in the southern part of the Eastern Alps have also observed a north dipping interface, which may penetrate the entire Adriatic crust [Adriatic Crust Interface (ACI)]. Deep crustal seismicity may be related to the ACI. We interpret the ACI as the currently active retroshear zone in the doubly vergent Alpine collisional belt. (C) 2004 Elsevier B.V. All rights reserved Y1 - 2004 ER - TY - JOUR A1 - Hinzen, K. G. A1 - Weber, B. A1 - Scherbaum, Frank T1 - On the resolution of H/V measurements to determine sediment thickness, a case study across a normal fault in the Lower Rhine Embayment, Germany N2 - In recent years, H/V measurements have been increasingly used to map the thickness of sediment fill in sedimentary basins in the context of seismic hazard assessment. This parameter is believed to be an important proxy for the site effects in sedimentary basins (e.g. in the Los Angeles basin). Here we present the results of a test using this approach across an active normal fault in a structurally well known situation. Measurements on a 50 km long profile with 1 km station spacing clearly show a change in the frequency of the fundamental peak of H/V ratios with increasing thickness of the sediment layer in the eastern part of the Lower Rhine Embayment. Subsequently, a section of 10 km length across the Erft-Sprung system, a normal fault with ca. 750 m vertical offset, was measured with a station distance of 100 m. Frequencies of the first and second peaks and the first trough in the H/V spectra are used in a simple resonance model to estimate depths of the bedrock. While the frequency of the first peak shows a large scatter for sediment depths larger than ca. 500 m, the frequency of the first trough follows the changing thickness of the sediments across the fault. The lateral resolution is in the range of the station distance of 100 m. A power law for the depth dependence of the S-wave velocity derived from down hole measurements in an earlier study [Budny, 1984] and power laws inverted from dispersion analysis of micro array measurements [Scherbaum et al., 2002] agree with the results from the H/V ratios of this study Y1 - 2004 SN - 1363-2469 ER - TY - JOUR A1 - Malischewsky, Peter G. A1 - Scherbaum, Frank T1 - Love's formula and H/V-ratio (ellipticity) of Rayleigh waves N2 - The ellipticity of Rayleigh surface waves, which is an important parameter characterizing the propagation medium, is studied for several models with increasing complexity. While the main focus lies on theory, practical implications of the use of the horizontal to vertical component ratio (H/V-ratio) to Study the subsurface structure are considered as well. Love's approximation of the ellipticity for an incompressible layer over an incompressible half-space is critically discussed especially concerning its applicability for different impedance contrasts. The main result is an analytically exact formula of H/V for a 2-layer model of compressible media, which is a generalization of Love's formula. It turns out that for a limited range of models Love's approximation can be used also in the general case. (C) 2003 Elsevier B.V. All rights reserved Y1 - 2004 SN - 0165-2125 ER - TY - JOUR A1 - Falsaperla, Susanna A1 - Wassermann, Joachim A1 - Scherbaum, Frank T1 - Solid earth - 29. Polarization analyses of broadband seismic data recorded on Stromboli Volcano (Italy) from 1996 to 1999 (DOI 10.1029-2001GLO14300) Y1 - 2002 ER - TY - CHAP A1 - Hainzl, Sebastian A1 - Scherbaum, Frank A1 - Zöller, Gert T1 - Spatiotemporal earthquake patterns N2 - Interdisziplinäres Zentrum für Musterdynamik und Angewandte Fernerkundung Workshop vom 9. - 10. Februar 2006 Y1 - 2006 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-7267 N1 - [Poster] ER - TY - GEN A1 - Hiemer, Stefan A1 - Rößler, Dirk A1 - Scherbaum, Frank T1 - Catalog of Swarm Earthquakes in Vogtland /West Bohemia in 2008/09 N2 - The document contains the catalog of earthquakes in Vogtland /West Bohemia within the period of 2008/10/19 -to- 2009/03/16. The events were recorded by a seismic mini-array operated by the Institute of Earthsciences, University of Postdam. N2 - Das Dokument enthält einen Katalog von Erdbeben im Vogtland/Westböhmen im Zeitraum 2008/10/19 -bis- 2009/03/16. Die Erdbeben wurden mit Hilfe eines seismologischen Miniarrays, welches vom Institut für Geowissenschaften, Universität Potsdam, aufgestellt wurde, registriert. KW - Vogtland/Westböhmen KW - Erdbebenschwarm 2008/09 KW - Arrayseismologie KW - Erdbebenkatalog KW - Vogtland/West Bohemia KW - earthquake swarm 2008/09 KW - array seismology KW - earthquake catalog Y1 - 2010 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-51710 ER - TY - GEN A1 - Hiemer, Stefan A1 - Rößler, Dirk A1 - Scherbaum, Frank T1 - Catalog of Swarm Earthquakes in Vogtland /West Bohemia in 2008/09 N2 - The document contains the catalog of earthquakes in Vogtland /West Bohemia within the period of 2008/10/19 -to- 2009/03/16. The events were recorded by a seismic mini-array operated by the Institute of Earthsciences, University of Postdam. N2 - Das Dokument enthält einen Katalog von Erdbeben im Vogtland/Westböhmen im Zeitraum 2008/10/19 -bis- 2009/03/16. Die Erdbeben wurden mit Hilfe eines seismologischen Miniarrays, welches vom Institut für Geowissenschaften, Universität Potsdam, aufgestellt wurde, registriert. KW - Vogtland/Westböhmen KW - Erdbebenschwarm 2008/09 KW - Arrayseismologie KW - Erdbebenkatalog KW - Vogtland/West Bohemia KW - earthquake swarm 2008/09 KW - array seismology KW - earthquake catalog Y1 - 2010 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-53837 ER - TY - BOOK A1 - Scherbaum, Frank A1 - Mzhavanadze, Nana A1 - Arom, Simha A1 - Rosenzweig, Sebastian A1 - Müller, Meinard ED - Scherbaum, Frank T1 - Tonal Organization of the Erkomaishvili Dataset: Pitches, Scales, Melodies and Harmonies T3 - Computational Analysis Of Traditional Georgian Vocal Music N2 - In this study we examine the tonal organization of a series of recordings of liturgical chants, sung in 1966 by the Georgian master singer Artem Erkomaishvili. This dataset is the oldest corpus of Georgian chants from which the time synchronous F0-trajectories for all three voices have been reliably determined (Müller et al. 2017). It is therefore of outstanding importance for the understanding of the tuning principles of traditional Georgian vocal music. The aim of the present study is to use various computational methods to analyze what these recordings can contribute to the ongoing scientific dispute about traditional Georgian tuning systems. Starting point for the present analysis is the re-release of the original audio data together with estimated fundamental frequency (F0) trajectories for each of the three voices, beat annotations, and digital scores (Rosenzweig et al. 2020). We present synoptic models for the pitch and the harmonic interval distributions, which are the first of such models for which the complete Erkomaishvili dataset was used. We show that these distributions can be very compactly be expressed as Gaussian mixture models, anchored on discrete sets of pitch or interval values for the pitch and interval distributions, respectively. As part of our study we demonstrate that these pitch values, which we refer to as scale pitches, and which are determined as the mean values of the Gaussian mixture elements, define the scale degrees of the melodic sound scales which build the skeleton of Artem Erkomaishvili’s intonation. The observation of consistent pitch bending of notes in melodic phrases, which appear in identical form in a group of chants, as well as the observation of harmonically driven intonation adjustments, which are clearly documented for all pure harmonic intervals, demonstrate that Artem Erkomaishvili intentionally deviates from the scale pitch skeleton quite freely. As a central result of our study, we proof that this melodic freedom is always constrained by the attracting influence of the scale pitches. Deviations of the F0-values of individual note events from the scale pitches at one instance of time are compensated for in the subsequent melodic steps. This suggests a deviation-compensation mechanism at the core of Artem Erkomaishvili’s melody generation, which clearly honors the scales but still allows for a large degree of melodic flexibility. This model, which summarizes all partial aspects of our analysis, is consistent with the melodic scale models derived from the observed pitch distributions, as well as with the melodic and harmonic interval distributions. In addition to the tangible results of our work, we believe that our work has general implications for the determination of tuning models from audio data, in particular for non-tempered music. T3 - Computational Analysis Of Traditional Georgian Vocal Music - 1 KW - computational ethnomusicology KW - traditional Georgian music KW - Georgian chant KW - Artem Erkomaishvili KW - musical scales KW - computergestützte Musikethnologie KW - traditionelle Georgische Musik KW - Georgische liturgische Gesänge KW - Artem Erkomaishvili KW - musikalische Tonleitern Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-476141 SN - 2702-2641 IS - 1 PB - Universitätsverlag Potsdam CY - Potsdam ER - TY - JOUR A1 - Vogel, Kristin A1 - Riggelsen, Carsten A1 - Korup, Oliver A1 - Scherbaum, Frank T1 - Bayesian network learning for natural hazard analyses JF - Natural hazards and earth system sciences N2 - Modern natural hazards research requires dealing with several uncertainties that arise from limited process knowledge, measurement errors, censored and incomplete observations, and the intrinsic randomness of the governing processes. Nevertheless, deterministic analyses are still widely used in quantitative hazard assessments despite the pitfall of misestimating the hazard and any ensuing risks. In this paper we show that Bayesian networks offer a flexible framework for capturing and expressing a broad range of uncertainties encountered in natural hazard assessments. Although Bayesian networks are well studied in theory, their application to real-world data is far from straightforward, and requires specific tailoring and adaptation of existing algorithms. We offer suggestions as how to tackle frequently arising problems in this context and mainly concentrate on the handling of continuous variables, incomplete data sets, and the interaction of both. By way of three case studies from earthquake, flood, and landslide research, we demonstrate the method of data-driven Bayesian network learning, and showcase the flexibility, applicability, and benefits of this approach. Our results offer fresh and partly counterintuitive insights into well-studied multivariate problems of earthquake-induced ground motion prediction, accurate flood damage quantification, and spatially explicit landslide prediction at the regional scale. In particular, we highlight how Bayesian networks help to express information flow and independence assumptions between candidate predictors. Such knowledge is pivotal in providing scientists and decision makers with well-informed strategies for selecting adequate predictor variables for quantitative natural hazard assessments. Y1 - 2014 U6 - https://doi.org/10.5194/nhess-14-2605-2014 SN - 1561-8633 VL - 14 IS - 9 SP - 2605 EP - 2626 PB - Copernicus CY - Göttingen ER - TY - JOUR A1 - Hinzen, Klaus-G A1 - Reamer, Sharon K. A1 - Scherbaum, Frank T1 - Slow fourier transform JF - Seismological research letters Y1 - 2013 U6 - https://doi.org/10.1785/0220120139 SN - 0895-0695 VL - 84 IS - 2 SP - 251 EP - 257 PB - Seismological Society of America CY - Albany ER - TY - JOUR A1 - Kühn, Nicolas M. A1 - Scherbaum, Frank A1 - Riggelsen, Carsten T1 - Deriving empirical ground-motion models : balancing data constraints and physical assumptions to optimize prediction capability N2 - Empirical ground-motion models used in seismic hazard analysis are commonly derived by regression of observed ground motions against a chosen set of predictor variables. Commonly, the model building process is based on residual analysis and/or expert knowledge and/or opinion, while the quality of the model is assessed by the goodness-of-fit to the data. Such an approach, however, bears no immediate relation to the predictive power of the model and with increasing complexity of the models is increasingly susceptible to the danger of overfitting. Here, a different, primarily data-driven method for the development of ground-motion models is proposed that makes use of the notion of generalization error to counteract the problem of overfitting. Generalization error directly estimates the average prediction error on data not used for the model generation and, thus, is a good criterion to assess the predictive capabilities of a model. The approach taken here makes only few a priori assumptions. At first, peak ground acceleration and response spectrum values are modeled by flexible, nonphysical functions (polynomials) of the predictor variables. The inclusion of a particular predictor and the order of the polynomials are based on minimizing generalization error. The approach is illustrated for the next generation of ground-motion attenuation dataset. The resulting model is rather complex, comprising 48 parameters, but has considerably lower generalization error than functional forms commonly used in ground-motion models. The model parameters have no physical meaning, but a visual interpretation is possible and can reveal relevant characteristics of the data, for example, the Moho bounce in the distance scaling. In a second step, the regression model is approximated by an equivalent stochastic model, making it physically interpretable. The resulting resolvable stochastic model parameters are comparable to published models for western North America. In general, for large datasets generalization error minimization provides a viable method for the development of empirical ground-motion models. Y1 - 2009 UR - http://bssa.geoscienceworld.org/ U6 - https://doi.org/10.1785/0120080136 SN - 0037-1106 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 - 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 - Wassermann, Joachim A1 - Ohrnberger, Matthias A1 - Scherbaum, Frank A1 - Gossler, J. A1 - Zschau, Jochen T1 - Kontinuierliche seismologische Netz- und Arraymessungen am Dekadenvulkan Merapi (Java, Indonesien) : ein Zwischenresümee = Continuous measurements at Merapi volcano (Java, Indonesia) using anetwork of small-scale seismograph arrays Y1 - 1998 SN - 0947-1944 ER - TY - JOUR A1 - Koehler, Andreas A1 - Ohrnberger, Matthias A1 - Scherbaum, Frank T1 - Unsupervised feature selection and general pattern discovery using Self-Organizing Maps for gaining insights into the nature of seismic wavefields N2 - This study presents an unsupervised feature selection and learning approach for the discovery and intuitive imaging of significant temporal patterns in seismic single-station or network recordings. For this purpose, the data are parametrized by real-valued feature vectors for short time windows using standard analysis tools for seismic data, such as frequency-wavenumber, polarization, and spectral analysis. We use Self-Organizing Maps (SOMs) for a data-driven feature selection, visualization and clustering procedure, which is in particular suitable for high-dimensional data sets. Our feature selection method is based on significance testing using the Wald-Wolfowitz runs test for-individual features and on correlation hunting with SOMs in feature subsets. Using synthetics composed of Rayleigh and Love waves and real-world data, we show the robustness and the improved discriminative power of that approach compared to feature subsets manually selected from individual wavefield parametrization methods. Furthermore, the capability of the clustering and visualization techniques to investigate the discrimination of wave phases is shown by means of synthetic waveforms and regional earthquake recordings. Y1 - 2009 UR - http://www.sciencedirect.com/science/journal/00983004 U6 - https://doi.org/10.1016/j.cageo.2009.02.004 SN - 0098-3004 ER - TY - JOUR A1 - Runge, Antonia K. A1 - Scherbaum, Frank A1 - Curtis, Andrew A1 - Riggelsen, Carsten T1 - An interactive tool for the elicitation of subjective probabilities in probabilistic seismic-hazard analysis JF - Bulletin of the Seismological Society of America N2 - In probabilistic seismic-hazard analysis, epistemic uncertainties are commonly treated within a logic-tree framework in which the branch weights express the degree of belief of an expert in a set of models. For the calculation of the distribution of hazard curves, these branch weights represent subjective probabilities. A major challenge for experts is to provide logically consistent weight estimates (in the sense of Kolmogorovs axioms), to be aware of the multitude of heuristics, and to minimize the biases which affect human judgment under uncertainty. We introduce a platform-independent, interactive program enabling us to quantify, elicit, and transfer expert knowledge into a set of subjective probabilities by applying experimental design theory, following the approach of Curtis and Wood (2004). Instead of determining the set of probabilities for all models in a single step, the computer-driven elicitation process is performed as a sequence of evaluations of relative weights for small subsets of models. From these, the probabilities for the whole model set are determined as a solution of an optimization problem. The result of this process is a set of logically consistent probabilities together with a measure of confidence determined from the amount of conflicting information which is provided by the expert during the relative weighting process. We experiment with different scenarios simulating likely expert behaviors in the context of knowledge elicitation and show the impact this has on the results. The overall aim is to provide a smart elicitation technique, and our findings serve as a guide for practical applications. Y1 - 2013 U6 - https://doi.org/10.1785/0120130026 SN - 0037-1106 SN - 1943-3573 VL - 103 IS - 5 SP - 2862 EP - 2874 PB - Seismological Society of America CY - Albany ER - TY - JOUR A1 - Scherbaum, Frank A1 - Bouin, M. P. T1 - FIR filter effects and nucleation phases Y1 - 1997 ER - TY - JOUR A1 - Scherbaum, Frank T1 - Zero Phase FIR filters in digital seismic acquisition systems : blessing or curse Y1 - 1997 ER - TY - JOUR A1 - Scherbaum, Frank A1 - Delavaud, Elise A1 - Riggelsen, Carsten T1 - Model selection in seismic hazard analysis : an information-theoretic perspective N2 - Although the methodological framework of probabilistic seismic hazard analysis is well established, the selection of models to predict the ground motion at the sites of interest remains a major challenge. Information theory provides a powerful theoretical framework that can guide this selection process in a consistent way. From an information- theoretic perspective, the appropriateness of models can be expressed in terms of their relative information loss (Kullback-Leibler distance) and hence in physically meaningful units (bits). In contrast to hypothesis testing, information-theoretic model selection does not require ad hoc decisions regarding significance levels nor does it require the models to be mutually exclusive and collectively exhaustive. The key ingredient, the Kullback-Leibler distance, can be estimated from the statistical expectation of log-likelihoods of observations for the models under consideration. In the present study, data-driven ground-motion model selection based on Kullback-Leibler-distance differences is illustrated for a set of simulated observations of response spectra and macroseismic intensities. Information theory allows for a unified treatment of both quantities. The application of Kullback-Leibler-distance based model selection to real data using the model generating data set for the Abrahamson and Silva (1997) ground-motion model demonstrates the superior performance of the information-theoretic perspective in comparison to earlier attempts at data- driven model selection (e.g., Scherbaum et al., 2004). Y1 - 2009 UR - http://bssa.geoscienceworld.org/ U6 - https://doi.org/10.1785/0120080347 SN - 0037-1106 ER - TY - JOUR A1 - Rietbrock, Andreas A1 - Scherbaum, Frank T1 - Crustal scattering at the KTB from a combined microearthquake and receiver analysis Y1 - 1998 ER - TY - JOUR A1 - Rietbrock, Andreas A1 - Scherbaum, Frank T1 - The GIANT analysis system (Graphical Interaktive Aftershock Network Toolbox) Y1 - 1998 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 - Hiemer, Stefan A1 - Rößler, Dirk A1 - Scherbaum, Frank T1 - Monitoring the West Bohemian earthquake swarm in 2008/2009 by a temporary small-aperture seismic array JF - Journal of seismology N2 - The most recent intense earthquake swarm in West Bohemia lasted from 6 October 2008 to January 2009. Starting 12 days after the onset, the University of Potsdam monitored the swarm by a temporary small-aperture seismic array at 10 km epicentral distance. The purpose of the installation was a complete monitoring of the swarm including micro-earthquakes (M (L) < 0). We identify earthquakes using a conventional short-term average/long-term average trigger combined with sliding-window frequency-wavenumber and polarisation analyses. The resulting earthquake catalogue consists of 14,530 earthquakes between 19 October 2008 and 18 March 2009 with magnitudes in the range of -aEuro parts per thousand 1.2 a parts per thousand currency signaEuro parts per thousand M (L) a parts per thousand currency signaEuro parts per thousand 2.7. The small-aperture seismic array substantially lowers the detection threshold to about M (c) = -aEuro parts per thousand 0.4, when compared to the regional networks operating in West Bohemia (M (c) > 0.0). In the course of this work, the main temporal features (frequency-magnitude distribution, propagation of back azimuth and horizontal slowness, occurrence rate of aftershock sequences and interevent-time distribution) of the recent 2008/2009 earthquake swarm are presented and discussed. Temporal changes of the coefficient of variation (based on interevent times) suggest that the swarm earthquake activity of the 2008/2009 swarm terminates by 12 January 2009. During the main phase in our studied swarm period after 19 October, the b value of the Gutenberg-Richter relation decreases from 1.2 to 0.8. This trend is also reflected in the power-law behavior of the seismic moment release. The corresponding total seismic moment release of 1.02x10(17) Nm is equivalent to M (L,max) = 5.4. KW - Swarm earthquakes KW - West Bohemia KW - Array seismology KW - Frequency-magnitude distribution Y1 - 2012 U6 - https://doi.org/10.1007/s10950-011-9256-5 SN - 1383-4649 VL - 16 IS - 2 SP - 169 EP - 182 PB - Springer CY - Dordrecht 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 - Haney, Frank A1 - Kummerow, J. A1 - Langenbruch, C. A1 - Dinske, C. A1 - Shapiro, Serge A. A1 - Scherbaum, Frank T1 - Magnitude estimation for microseismicity induced during the KTB 2004/2005 injection experiment JF - Geophysics N2 - We determined the magnitudes of 2540 microseismic events measured at one single 3C borehole geophone at the German Deep Drilling Site (known by the German acronym, KTB) during the injection phase 2004/2005. For this task we developed a three-step approach. First, we estimated local magnitudes of 104 larger events with a standard method based on amplitude measurements at near-surface stations. Second, we investigated a series of parameters to characterize the size of these events using the seismograms of the borehole sensor, and we compared them statistically with the local magnitudes. Third, we extrapolated the regression curve to obtain the magnitudes of 2436 events that were only measured at the borehole geophone. This method improved the magnitude of completeness for the KTB data set by more than one order down to M = -2.75. The resulting b-value for all events was 0.78, which is similar to the b-value obtained from taking only the greater events with standard local magnitude estimation from near-surface stations, b = 0.86. The more complete magnitude catalog was required to study the magnitude distribution with time and to characterize the seismotectonic state of the KTB injection site. The event distribution with time was consistent with prediction from theory assuming pore pressure diffusion as the underlying mechanism to trigger the events. The value we obtained for the seismogenic index of -4 suggested that the seismic hazard potential at the KTB site is comparatively low. Y1 - 2011 U6 - https://doi.org/10.1190/GEO2011-0020.1 SN - 0016-8033 VL - 76 IS - 6 SP - WC47 EP - WC53 PB - Society of Exploration Geophysicists CY - Tulsa ER - TY - JOUR A1 - Hiemer, Stefan A1 - Scherbaum, Frank A1 - Rößler, Dirk A1 - Kühn, Nicolas T1 - Determination of tau(0) and Rock Site kappa from Records of the 2008/2009 Earthquake Swarm in Western Bohemia JF - Seismological research letters Y1 - 2011 U6 - https://doi.org/10.1785/gssrl.82.3.387 SN - 0895-0695 VL - 82 IS - 3 SP - 387 EP - 393 PB - Seismological Society of America CY - El Cerrito ER - TY - JOUR A1 - Gianniotis, Nikolaos A1 - Kuehn, Nicolas A1 - Scherbaum, Frank T1 - Manifold aligned ground motion prediction equations for regional datasets JF - Computers & geosciences : an international journal devoted to the publication of papers on all aspects of geocomputation and to the distribution of computer programs and test data sets ; an official journal of the International Association for Mathematical Geology N2 - Inferring a ground-motion prediction equation (GMPE) for a region in which only a small number of seismic events has been observed is a challenging task. A response to this data scarcity is to utilise data from other regions in the hope that there exist common patterns in the generation of ground motion that can contribute to the development of a GMPE for the region in question. This is not an unreasonable course of action since we expect regional GMPEs to be related to each other. In this work we model this relatedness by assuming that the regional GMPEs occupy a common low-dimensional manifold in the space of all possible GMPEs. As a consequence, the GMPEs are fitted in a joint manner and not independent of each other, borrowing predictive strength from each other's regional datasets. Experimentation on a real dataset shows that the manifold assumption displays better predictive performance over fitting regional GMPEs independent of each other. (C) 2014 Elsevier Ltd. All rights reserved. KW - Ground-motion-model KW - Bagging KW - Ensembles KW - Manifold KW - Regional-dependence Y1 - 2014 U6 - https://doi.org/10.1016/j.cageo.2014.04.014 SN - 0098-3004 SN - 1873-7803 VL - 69 SP - 72 EP - 77 PB - Elsevier CY - Oxford ER - TY - JOUR A1 - Kühn, Nico M. A1 - Scherbaum, Frank T1 - Ground-motion prediction model building: a multilevel approach JF - Bulletin of earthquake engineering : official publication of the European Association for Earthquake Engineering N2 - A Bayesian ground-motion model is presented that directly estimates the coefficients of the model and the correlation between different ground-motion parameters of interest. The model is developed as a multi-level model with levels for earthquake, station and record terms. This separation allows to estimate residuals for each level and thus the estimation of the associated aleatory variability. In particular, the usually estimated within-event variability is split into a between-station and between-record variability. In addition, the covariance structure between different ground-motion parameters of interest is estimated for each level, i.e. directly the between-event, between-station and between-record correlation coefficients are available. All parameters of the model are estimated via Bayesian inference, which allows to assess their epistemic uncertainty in a principled way. The model is developed using a recently compiled European strong-motion database. The target variables are peak ground velocity, peak ground acceleration and spectral acceleration at eight oscillator periods. The model performs well with respect to its residuals, and is similar to other ground-motion models using the same underlying database. The correlation coefficients are similar to those estimated for other parts of the world, with nearby periods having a high correlation. The between-station, between-event and between-record correlations follow generally a similar trend. KW - Ground-motion prediction equation KW - Probabilistic seismic hazard analysis and Bayesian inference KW - Multilevel model KW - Correlation KW - Single-station sigma Y1 - 2015 U6 - https://doi.org/10.1007/s10518-015-9732-3 SN - 1570-761X SN - 1573-1456 VL - 13 IS - 9 SP - 2481 EP - 2491 PB - Springer CY - Dordrecht ER - TY - JOUR A1 - Kühn, Nicolas M. A1 - Riggelsen, Carsten A1 - Scherbaum, Frank T1 - Modeling the joint probability of earthquake, site, and ground-motion parameters using bayesian networks JF - Bulletin of the Seismological Society of America N2 - Bayesian networks are a powerful and increasingly popular tool for reasoning under uncertainty, offering intuitive insight into (probabilistic) data-generating processes. They have been successfully applied to many different fields, including bioinformatics. In this paper, Bayesian networks are used to model the joint-probability distribution of selected earthquake, site, and ground-motion parameters. This provides a probabilistic representation of the independencies and dependencies between these variables. In particular, contrary to classical regression, Bayesian networks do not distinguish between target and predictors, treating each variable as random variable. The capability of Bayesian networks to model the ground-motion domain in probabilistic seismic hazard analysis is shown for a generic situation. A Bayesian network is learned based on a subset of the Next Generation Attenuation (NGA) dataset, using 3342 records from 154 earthquakes. Because no prior assumptions about dependencies between particular parameters are made, the learned network displays the most probable model given the data. The learned network shows that the ground-motion parameter (horizontal peak ground acceleration, PGA) is directly connected only to the moment magnitude, Joyner-Boore distance, fault mechanism, source-to-site azimuth, and depth to a shear-wave horizon of 2: 5 km/s (Z2.5). In particular, the effect of V-S30 is mediated by Z2.5. Comparisons of the PGA distributions based on the Bayesian networks with the NGA model of Boore and Atkinson (2008) show a reasonable agreement in ranges of good data coverage. Y1 - 2011 U6 - https://doi.org/10.1785/0120100080 SN - 0037-1106 VL - 101 IS - 1 SP - 235 EP - 249 PB - Seismological Society of America CY - El Cerrito ER - TY - JOUR A1 - Tran Thanh Tuan, A1 - Scherbaum, Frank A1 - Malischewsky, Peter G. T1 - On the relationship of peaks and troughs of the ellipticity (H/V) of Rayleigh waves and the transmission response of single layer over half-space models JF - Geophysical journal international N2 - One of the key challenges in the context of local site effect studies is the determination of frequencies where the shakeability of the ground is enhanced. In this context, the H/V technique has become increasingly popular and peak frequencies of H/V spectral ratio are sometimes interpreted as resonance frequencies of the transmission response. In the present study, assuming that Rayleigh surface wave is dominant in H/V spectral ratio, we analyse theoretically under which conditions this may be justified and when not. We focus on 'layer over half-space' models which, although seemingly simple, capture many aspects of local site effects in real sedimentary structures. Our starting point is the ellipticity of Rayleigh waves. We use the exact formula of the H/V-ratio presented by Malischewsky & Scherbaum (2004) to investigate the main characteristics of peak and trough frequencies. We present a simple formula illustrating if and where H/V-ratio curves have sharp peaks in dependence of model parameters. In addition, we have constructed a map, which demonstrates the relation between the H/V-peak frequency and the peak frequency of the transmission response in the domain of the layer's Poisson ratio and the impedance contrast. Finally, we have derived maps showing the relationship between the H/V-peak and trough frequency and key parameters of the model such as impedance contrast. These maps are seen as diagnostic tools, which can help to guide the interpretation of H/V spectral ratio diagrams in the context of site effect studies. KW - Site effects KW - Theoretical seismology KW - Wave propagation Y1 - 2011 U6 - https://doi.org/10.1111/j.1365-246X.2010.04863.x SN - 0956-540X VL - 184 IS - 2 SP - 793 EP - 800 PB - Wiley-Blackwell CY - Malden 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 - Scherbaum, Frank A1 - Kühn, Nicolas M. T1 - Logic tree branch weights and probabilities summing up to one is not enough JF - Earthquake spectra : the professional journal of the Earthquake Engineering Research Institute N2 - Logic trees have become the most popular tool for the quantification of epistemic uncertainties in probabilistic seismic hazard assessment (PSHA). In a logic-tree framework, epistemic uncertainty is expressed in a set of branch weights, by which an expert or an expert group assigns degree-of-belief values to the applicability of the corresponding branch models. Despite the popularity of logic-trees, however, one finds surprisingly few clear commitments to what logic-tree branch weights are assumed to be (even by hazard analysts designing logic trees). In the present paper we argue that it is important for hazard analysts to accept the probabilistic framework from the beginning for assigning logic-tree branch weights. In other words, to accept that logic-tree branch weights are probabilities in the axiomatic sense, independent of one's preference for the philosophical interpretation of probabilities. We demonstrate that interpreting logic-tree branch weights merely as a numerical measure of "model quality," which are then subsequently normalized to sum up to unity, will with increasing number of models inevitably lead to an apparent insensitivity of hazard curves on the logic-tree branch weights, which may even be mistaken for robustness of the results. Finally, we argue that assigning logic-tree branch weights in a sequential fashion may improve their logical consistency. Y1 - 2011 U6 - https://doi.org/10.1193/1.3652744 SN - 8755-2930 VL - 27 IS - 4 SP - 1237 EP - 1251 PB - Earthquake Engineering Research Institute CY - Oakland ER - TY - JOUR A1 - Rodriguez-Marek, A. A1 - Rathje, E. M. A1 - Bommer, Julian J. A1 - Scherbaum, Frank A1 - Stafford, P. J. T1 - Application of single-station sigma and site-response characterization in a probabilistic Seismic-Hazard analysis for new uclear site JF - Bulletin of the Seismological Society of America N2 - Aleatory variability in ground-motion prediction, represented by the standard deviation (sigma) of a ground-motion prediction equation, exerts a very strong influence on the results of probabilistic seismic-hazard analysis (PSHA). This is especially so at the low annual exceedance frequencies considered for nuclear facilities; in these cases, even small reductions in sigma can have a marked effect on the hazard estimates. Proper separation and quantification of aleatory variability and epistemic uncertainty can lead to defensible reductions in sigma. One such approach is the single-station sigma concept, which removes that part of sigma corresponding to repeatable site-specific effects. However, the site-to-site component must then be constrained by site-specific measurements or else modeled as epistemic uncertainty and incorporated into the modeling of site effects. The practical application of the single-station sigma concept, including the characterization of the dynamic properties of the site and the incorporation of site-response effects into the hazard calculations, is illustrated for a PSHA conducted at a rock site under consideration for the potential construction of a nuclear power plant. Y1 - 2014 U6 - https://doi.org/10.1785/0120130196 SN - 0037-1106 SN - 1943-3573 VL - 104 IS - 4 SP - 1601 EP - 1619 PB - Seismological Society of America CY - Albany ER - TY - JOUR A1 - Kuehn, Nicolas M. A1 - Scherbaum, Frank T1 - A partially non-ergodic ground-motion prediction equation for Europe and the Middle East JF - Bulletin of earthquake engineering : official publication of the European Association for Earthquake Engineering N2 - A partially non-ergodic ground-motion prediction equation is estimated for Europe and the Middle East. Therefore, a hierarchical model is presented that accounts for regional differences. For this purpose, the scaling of ground-motion intensity measures is assumed to be similar, but not identical in different regions. This is achieved by assuming a hierarchical model, where some coefficients are treated as random variables which are sampled from an underlying global distribution. The coefficients are estimated by Bayesian inference. This allows one to estimate the epistemic uncertainty in the coefficients, and consequently in model predictions, in a rigorous way. The model is estimated based on peak ground acceleration data from nine different European/Middle Eastern regions. There are large differences in the amount of earthquakes and records in the different regions. However, due to the hierarchical nature of the model, regions with only few data points borrow strength from other regions with more data. This makes it possible to estimate a separate set of coefficients for all regions. Different regionalized models are compared, for which different coefficients are assumed to be regionally dependent. Results show that regionalizing the coefficients for magnitude and distance scaling leads to better performance of the models. The models for all regions are physically sound, even if only very few earthquakes comprise one region. KW - Ground-motion prediction equation KW - Non-ergodic PSHA KW - Hierarchical model Y1 - 2016 U6 - https://doi.org/10.1007/s10518-016-9911-x SN - 1570-761X SN - 1573-1456 VL - 14 SP - 2629 EP - 2642 PB - Springer CY - Dordrecht 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 - Suryanto, Wiwit A1 - Igel, Heiner A1 - Wassermann, Joachim A1 - Cochard, Alain A1 - Schuberth, B. S. A. A1 - Vollmer, Daniel A1 - Scherbaum, Frank A1 - Schreiber, U. A1 - Velikoseltsev, A. T1 - First comparison of array-derived rotational ground motions with direct ring laser measurements JF - Bulletin of the Seismological Society of America N2 - Recently, ring laser technology has provided the first consistent observations of rotational ground motions around a vertical axis induced by earthquakes. "Consistent," in this context, implies that the observed waveforms and amplitudes are compatible with collocated recordings of translational ground motions. In particular, transverse accelerations should be in phase with rotation rate and their ratio proportional to local horizontal phase velocity assuming plane-wave propagation. The ring laser installed at the Fundamental station Wettzell in the Bavarian Forest, Southeast Germany, is recording the rotation rate around a vertical axis, theoretically a linear combination of the space derivatives of the horizontal components of motion. This suggests that, in principle, rotation can be derived from seismic-array experiments by "finite differencing." This has been attempted previously in several studies; however, the accuracy of these observations could never be tested in the absence of direct measurements. We installed a double cross-shaped array of nine stations from December 2003 to March 2004 around the ring laser instrument and observed several large earthquakes on both the ring laser and the seismic array. Here we present for the first time a comparison of array-derived rotations with direct measurements of rotations for ground motions induced by the M 6.3 Al Hoceima, Morocco, earthquake of 24 February 2004. With complete 3D synthetic seismograms calculated for this event we show that even low levels of noise may considerably influence the accuracy of the array-derived rotations when the minimum number of required stations (three) is used. Nevertheless, when using all nine stations, the overall fit between direct and array-derived measurements is surprisingly good (maximum correlation coefficient of 0.94). Y1 - 2006 U6 - https://doi.org/10.1785/0120060004 SN - 0037-1106 SN - 1943-3573 VL - 96 IS - 6 SP - 2059 EP - 2071 PB - GeoScienceWorld CY - Alexandria, Va. 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 - Scherbaum, Frank A1 - Schmidtke, E. T1 - Digital seismology tutor Y1 - 2001 ER - TY - BOOK A1 - Scherbaum, Frank T1 - Of poles and zeros : fundamentals of digital seismology T3 - Modern approaches in geophysics Y1 - 2001 SN - 0-7923-6834-7 VL - 15 PB - Springer CY - Dordrecht ET - Rev. 2. ed., reprint with corr ER - TY - JOUR A1 - Thomas, Ch. A1 - Igel, Heiner A1 - Weber, Michael H. A1 - Scherbaum, Frank T1 - Acoustic simulation of P-wave propagation in a heterogeneous spherical earth : numerical method and application to precursor waves to PKPdf Y1 - 2000 ER -