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Douglas, John
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- PublicationOpen AccessComparisons 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(2014-02)
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ;Douglas, J.; BRGM, Orléans, France ;Akkar, S.; Middle East Technical University, Ankara, Turkey ;Ameri, G.; FUGRO-Geoter, Auriol, France. ;Bard, P.; ISTerre, Grenoble, France ;Bindi, D.; GFZ, Potsdam, Germany ;Bommer, J.; Imperial College London, United Kingdom ;Bora, S. S.; Inst. Erd- und Umweltwissesnschaften, Universitaet Potsdam, Germany ;Cotton, F.; ISTerre, Grenoble, France ;Derras, B.; ISTerre, Grenoble, France ;Hermkes, M.; Inst. Erd- und Umweltwissesnschaften, Universitaet Potsdam, Germany ;Kuehn, N. M.; Inst. Erd- und Umweltwissesnschaften, Universitaet Potsdam, Germany ;Luzi, L.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Milano-Pavia, Milano, Italia ;Massa, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Milano-Pavia, Milano, Italia ;Pacor, F.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Milano-Pavia, Milano, Italia ;Riggelsen, C.; Inst. Erd- und Umweltwissesnschaften, Universitaet Potsdam, Germany ;Sandikkaya, M. A.; Middle East Technical University, Ankara, Turkey ;Scherbaum, F.; Inst. Erd- und Umweltwissesnschaften, Universitaet Potsdam, Germany ;Stafford, P.; Imperial College London, United Kingdom ;Traversa, P.; EDF, Aix en Provence, France; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; 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.214 263 - PublicationRestrictedPredicting Ground Motion from Induced Earthquakes in Geothermal Areas(2013)
; ; ; ; ; ; ; ; ; ; ;; ;; ; ; ;Induced seismicity from anthropogenic sources can be a significant nuisance to a local population and in extreme cases lead to damage to vulnerable structures. One type of induced seismicity of particular recent concern, which, in some cases, can limit development of a potentially important clean energy source, is that associated with geothermal power production. A key requirement for the accurate assessment of seismic hazard (and potential eventual risk) is a ground-motion prediction equation (GMPE) that predicts the level of earthquake shaking (in terms of, for example, peak ground acceleration) of an earthquake of a certain magnitude at a particular distance. Few such models currently exist in regards to geothermal-related seismicity and consequently the evaluation of seismic hazard in the vicinity of geothermal power plants is associated with high uncertainty. Various ground-motion datasets of induced and natural seismicity (from Basel, Geysers, Hengill, Roswinkel, Soultz, and Voerendaal) were compiled and processed, and moment magnitudes for all events were recomputed homogeneously. These data are used to show that ground motions from induced and natural earthquakes cannot be statistically distinguished. Empirical GMPEs are derived from these data and it is shown that although they have similar characteristics to other recent GMPEs for natural and mining-related seismicity, the standard deviations are higher. Subsequently stochastic models to account for epistemic uncertainties are developed based on a single corner frequency and with parameters constrained by the available data. Predicted ground motions from these models are fitted with functional forms to obtain easy-to-use GMPEs. These are associated with standard deviations derived from the empirical data to characterize aleatory variability. As an example, we demonstrate the potential use of these models using data from Campi Flegrei.89 2 - PublicationOpen AccessAccessing European Strong-Motion Data: An Update on ORFEUS Coordinated Services(2021)
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ;; ; ;; ; ; ; ;; ; ; ;; ;; ;; ; ;Strong ground motion records and free open access to strong‐motion data repositories are fundamental inputs to seismology, engineering seismology, soil dynamics, and earthquake engineering science and practice. This article presents the current status and outlook of the Observatories and Research Facilities for European Seismology (ORFEUS) coordinated strong‐motion seismology services, namely the rapid raw strong‐motion (RRSM) and the engineering strong‐motion (ESM) databases and associated web interfaces and webservices. We compare and discuss the role and use of these two systems using the Mw 6.5 Norcia (Central Italy) earthquake that occurred on 30 October 2016 as an example of a well‐recorded earthquake that triggered major interest in the seismological and earthquake engineering communities. The RRSM is a fully automated system for rapid dissemination of earthquake shaking information, whereas the ESM provides quality‐checked, manually processed waveforms and reviewed earthquake information. The RRSM uses only data from the European Integrated Waveform Data Archive, whereas the ESM also includes offline data from other sources, such as the ITalian ACcelerometric Archive (ITACA). Advanced software tools are also included in the ESM to allow users to process strong‐motion data and to select ground‐motion waveform sets for seismic structural analyses. The RRSM and ESM are complementary services designed for a variety of possible stakeholders, ranging from scientists to the educated general public. The RRSM and ESM are developed, organized, and reviewed by selected members of the seismological community in Europe, including strong‐motion data providers and expert users. Global access and usage of the data is encouraged. The ESM is presently the reference database for harmonized seismic hazard and risk studies in Europe. ORFEUS strong‐motion data are open, “Findable, Accessible, Interoperable, and Reusable,” and accompanied by licensing information. The users are encouraged to properly cite the data providers, using the digital object identifiers of the seismic networks.879 101 - PublicationRestrictedToward a ground-motion logic tree for probabilistic seismic hazard assessment in Europe(2012-02-22)
; ; ; ; ; ; ; ; ; ; ; ; ; ;Delavaud, E.; ISTerre, Université Joseph Fourier, CNRS, BP 53, 38041 Grenoble, France ;Cotton, F.; ISTerre, Université Joseph Fourier, CNRS, BP 53, 38041 Grenoble, France ;Akkar, S.; Earthquake Engineering Research Center, Department of Civil Engineering, METU, 06531 Ankara, Turkey ;Scherbaum, F.; Institute of Earth and Environmental Sciences, University of Potsdam, Karl-Liebknecht-Strasse 24-25, 14476 Golm, Germany ;Danciu, L.; Swiss Seismological Service, Institute of Geophysics, ETH Zurich, Sonneggstrasse 5, NO, 8092 Zurich, Switzerland ;Beauval, C.; ISTerre, Université Joseph Fourier, CNRS, BP 53, 38041 Grenoble, France ;Drouet, S.; ISTerre, Université Joseph Fourier, CNRS, BP 53, 38041 Grenoble, France ;Douglas, J.; RIS/RSI, BRGM, 3 avenue C. Guillemin, BP 36009, 45060 Orléans Cedex 2, France ;Basili, R.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia ;Sandikkaya, M. A.; Earthquake Engineering Research Center, Department of Civil Engineering, METU, 06531 Ankara, Turkey ;Segou, M.; Earthquake Engineering Research Center, Department of Civil Engineering, METU, 06531 Ankara, Turkey ;Faccioli, E.; Politecnico di Milano, Piazza L. da Vinci, 32, 20133 Milan, Italy ;Theodoulidis, N.; ITSAK, P.O. Box 53, Finikas 55102 Thessaloniki, Greece; ; ; ; ; ; ; ; ; ; ; ; 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.258 20 - PublicationRestrictedComment on "Influence of fochal mechanism in probabilistic seismic hazard analysis" by Vincenzo Convertito and Andre' Herrero(2006)
; ; ; ; ;Strasser, F. O.; Department of Civil & Environmental Engineering Imperial College London ;Montaldo, V.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Milano-Pavia, Milano, Italia ;Douglas, J.; BRGM, ARN/RIS ;Bommer, J. J.; Department of Civil & Environmental Engineering Imperial College London; ; ; The influence of style-of-faulting on strong groundmotions has been the subject of debate for some time. Although some controversy persists, the general consensus is that ground motions produced by reverse faults are higher than those produced by normal faults, whereas motions from strike-slip faults are somewhere in between. In a recent article, Convertito and Herrero (2004) derived a correction factor for focal mechanism to be applied to predictive equations. This issue was previously addressed by Bommer et al. (2003). Although this article is cited by Convertito and Herrero, it seems that its aims and scope were not well understood, and we would therefore like to clarify what the method presented therein entails, especially because we feel that Convertito and Herrero’s approach of characterizing focal mechanisms based solely on the radiation pattern is difficult to justify. After presenting their correction scheme, Convertito and Herrero go on to present an implementation of probabilistic seismic hazard analysis (PSHA) explicitly accounting for focal mechanism. This represents a real innovation in terms of methodology because it allows propagation of the improvements in ground-motion prediction gained through the focal-mechanism adjustments to hazard estimation. Characterizing the dominant scenario in terms of focal mechanism furthermore has the advantage of providing constraints for numerical simulations that are derived directly from the hazard computation, rather than from arbitrary assumptions. However, in our opinion, the methodology presented by Convertito and Herrero has some serious shortcomings which would need to be addressed before it can lead to improvements of the PSHA methodology. Our discussion includes a comparison with the new Italian seismic hazard map, which was derived using the Bommer et al. (2003) adjustment methodology.194 30