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Beauval, CeĢline
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Beauval, CeĢline
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- PublicationOpen Access3D GNSS Velocity Field Sheds Light on the Deformation Mechanisms in Europe: Effects of the Vertical Crustal Motion on the Distribution of SeismicityCrustal deformation and seismicity in Europe are still poorly understood. Seismic activity is classically ascribed to crustal strain rates generated by edge-driven tectonic forces. However, crustal deformation is not only due to tectonic loading, but can also be related to isostatic and mantellic processes that induce additional stress and strain on the crust by flexure. The influence that those processes have on seismic activity, as well their interaction, is still controversial. The main limitation to study it is because the deformation and its causal mechanisms are usually analyzed separately in small regions. We present here a 3D secular velocity field that covers Eurasia and its plate boundaries including 4,863 Global Navigation Satellite System stations obtained by combining 10 different datasets. We have developed a method based on spatial filtering to identify outliers and smooth the velocity field, and have computed both strain and uplift rate maps that are interpreted in the light of the different driving processes that contribute to the 3D deformation in Europe. The vertical and horizontal deformation features are compared with seismic rates obtained from the spatial and temporal distribution of the seismicity in Europe. Our results suggest that is not possible to explain the seismicity in Europe with edge-driven horizontal tectonic forces only. In some areas markers of the crustal flexure such as the vertical velocity field and its derivative, resulting from buoyancy-driven processes, may help to interpret earthquake distribution.
61 73 - ProductOpen AccessEuropean Fault-Source Model 2020 (EFSM20): online data on fault geometry and activity parameters(2022-10-25)
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ;; ; ; ; ; ; ; ; ; ; ;; ; ; ; ; ; ;; ; ;; ;72 194 - PublicationOpen AccessThe 2020 European Seismic Hazard Model: Milestones and Lessons Learned(Springer Nature, 2022-08-25)
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ;; ; ; ; ; ; ; ; ; ; ; ; ;The 2020 update of the European Seismic Hazard Model (ESHM20) is the most recent seismic hazard model of the Euro-Mediterranean region. It was built upon unified and homogenized datasets including earthquake catalogues, active faults, ground motion recordings and state-of-the-art modelling components, i.e. earthquake rates forecast and regionally variable ground motion characteristic models. ESHM20 replaces the 2013 European Seismic Hazard Model (ESHM13), and it is the first regional model to provide two informative hazard maps for the next update of the European Seismic Design Code (CEN EC8). ESHM20 is also one of the key components of the first publicly available seismic risk model for Europe. This chapter provides a short summary of ESHM20 by highlighting its main features and describing some lessons learned during the modelās development.61 54 - PublicationRestrictedAn Earthquake Catalog for the Lebanese Region(2019-09-18)
; ; ; ; ; ; ; ; ; The present work aims at establishing an earthquake catalog for seismic hazard assessment in Lebanon. This catalog includes two different parts: historical earthquakes and instrumental earth- quakes. The first part of the article describes the work done on the period 31 B.C.E. to the end of the nineteenth century. Numerous studies published in the last 30 yr, devoted to pre- instrumental earthquakes in Lebanon, had not been included in any parametric earthquake catalog. A thorough and critical review of these studies was devised to check their respective interpretations of available earthquake records in terms of seis- mic parameters (date, location, and size) and to select for each earthquake the most reliable interpretation. The second part provides the details on the selection of instrumental solutions for the period 1900ā2015 and for magnitudes ā„ 4. From global instrumental earthquake catalogs, we build a unified earthquake catalog for Lebanon and bordering regions. A selection scheme is applied for the choice of the best location and the best magni- tude among solutions available. The number of events in the catalog is relatively small, and all earthquakes can be checked one by one. The earthquake catalog is homogenized in moment magnitude. For 89% of the events, an Mw proxy was calculated from the original magnitude, applying conversion equations. The merging of the historical and instrumental periods high- lights a specificity of this zone: the instrumental seismicity (1900ā2015) corresponds to a relatively quiet period for Lebanon. The historical part, covering 2000 yr, includes similar periods of quiescence, as well as much more active periods with destructive earthquakes.363 5 - PublicationRestrictedTwentieth century seismicity of the Koffiefontein region (Free State, South Africa): consistent determination of earthquake catalogue parameters from mixed data typesThe preparation of earthquake catalogues for seismic hazard analysis requires the use of uniform parameters, in particular for magnitudes, although the original data include a variety of formats, such as macroseismic intensities and various instrumental mag- nitude scales. In regions of low seismicity, such as South Africa, data are generally sparse and not always suffi- cient to develop locally calibrated conversion relations. They can nevertheless be used to test the applicability of imported conversion relations, as well as their consis- tency. The Koffiefontein region of South Africa pro- vides a good test case in view of its somewhat higher level of seismicity, and central geographic location with- in the country. This paper reviews determinations of location and magnitude parameters for a suite of moderate-to-large earthquakes that have occurred in this region between 1903 and 1985.
371 1 - PublicationRestrictedToward a ground-motion logic tree for probabilistic seismic hazard assessment in Europe(2012-02-22)
; ; ; ; ; ; ; ; ; ; ; ; ; ;Delavaud, E.; ISTerre, UniversitĆ© Joseph Fourier, CNRS, BP 53, 38041 Grenoble, France ;Cotton, F.; ISTerre, UniversitĆ© 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, UniversitĆ© Joseph Fourier, CNRS, BP 53, 38041 Grenoble, France ;Drouet, S.; ISTerre, UniversitĆ© Joseph Fourier, CNRS, BP 53, 38041 Grenoble, France ;Douglas, J.; RIS/RSI, BRGM, 3 avenue C. Guillemin, BP 36009, 45060 OrlĆ©ans 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 99:3234ā3247, 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 - PublicationOpen AccessThe 2020 update of the European Seismic Hazard Model: Model Overview. EFEHR Technical Report 001, v1.0.0(2021-11-16)
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ;; ; ;; ; ; ; ; ;Executive Summary The 2020 European Seismic Hazard Model (ESHM20) provides an update of the earthquake hazard assessment of the Euro-Mediterranean region. ESHM20 has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No.s 730900 of the SERAProject (www.sera-eu.org) The ESHM20 follows the same principles as the ESHM13, with state-of-the art procedures homogeneously applied for the entire pan-European region, without the country-borders issues. The model was built upon recently compiled datasets (i.e. earthquake catalogues, active faults, ground shaking recordings), information (tectonic and geological) and models (seismogenic sources, ground shaking). A fully probabilistic framework was adopted in the hazard model implementation and all datasets and inputs are fully cross-border harmonized. The newly developed seismogenic source model encompass fully harmonized and cross borders seismogenic sources following the recent national earthquake hazard models. The inherent uncertainties in characterizing the earthquake rupture forecast are handled by a complex logic tree, consisting of two main models (branches): an area source-based model and a hybrid fault-smoothed seismicity model. The ground motion characteristic model is built upon the most complete ground shaking recordings in Europe and aims at capturing the effects of source and attenuation path of the expected ground shaking at a site. The regional variability of the ground shaking as constrain by observations is captured by a novel approach of spatial clustering and the overall uncertainties are handled in a backbone logic tree. The master logic tree combines the earthquake rate forecast with the backbone ground motion models into a computational model for assessing the earthquake ground shaking at across the entire Euro- Mediterranean region. Full sets of hazard results (i.e. hazard curves and maps, uniform hazard spectra) for various combinations of return periods and descriptive statistics (mean, median and quantiles) are available. The ESHM20 development process involved several regional workshops where the scientists and experts were consulted and their feedback was acknowledged and considered on the model outcome. Finally, ESHM20 provides the basis to derive informative hazard maps for two key engineering parameters defining the anchoring points of the seismic design spectra for the next version of the European Seismic Design Code (CEN-EC8). The European Facilities for Earthquake Hazard and Risk (EFEHR) will maintain and further develop this model in collaboration with the GEM Foundation and the European Plate Observing System (EPOS). The source data, input models, software and outputs of ESRM20 are thus being openly released with a Creative Commons CC-BY International 4.0 license (https://creativecommons.org/licenses/by/4.0/). This license allows re-users to distribute, remix, adapt, and build upon the material in any medium or format, so long as attribution is given to the creator. The license allows for commercial use. Each product is released with a clear notice on how it should be cited in order to abide by the license. ESHM20 is online available at the www.hazard.EFEHR.org.394 1398