ALBERT

Description: The selection of ground motion models, and the representation of their epistemic uncertainty in the form of a logic tree, is one of the fundamental components of probabilistic seismic hazard and risk analysis. A new ground motion model (GMM) logic tree has been developed for the 2020 European seismic hazard model, which develops upon recently compiled ground motion data sets in Europe. In contrast to previous European seismic hazard models, the new ground model logic tree is built around the scaled backbone concept. Epistemic uncertainties are represented as calibrations to a reference model and aim to characterise the potential distributions of median ground motions resulting from variability in source scaling and attenuation. These scaled backbone logic trees are developed and presented for shallow crustal seismic sources in Europe. Using the new European strong motion flatfile, and capitalising on recent perspectives in ground motion modelling in the scientific literature, a general and transferable procedure is presented for the construction of a backbone model and the regionalisation of epistemic uncertainty. This innovative approach forms a general framework for revising and updating the GMM logic tree at national and European scale as new strong motion data emerge in the future.

Description: Horizon 2020 http://dx.doi.org/10.13039/501100007601

Description: Regions of low seismicity present a particular challenge for probabilistic seismic hazard analysis when identifying suitable ground motion models (GMMs) and quantifying their epistemic uncertainty. The 2020 European Seismic Hazard Model adopts a scaled backbone approach to characterise this uncertainty for shallow seismicity in Europe, incorporating region-to-region source and attenuation variability based on European strong motion data. This approach, however, may not be suited to stable cratonic region of northeastern Europe (encompassing Finland, Sweden and the Baltic countries), where exploration of various global geophysical datasets reveals that its crustal properties are distinctly different from the rest of Europe, and are instead more closely represented by those of the Central and Eastern United States. Building upon the suite of models developed by the recent NGA East project, we construct a new scaled backbone ground motion model and calibrate its corresponding epistemic uncertainties. The resulting logic tree is shown to provide comparable hazard outcomes to the epistemic uncertainty modelling strategy adopted for the Eastern United States, despite the different approaches taken. Comparison with previous GMM selections for northeastern Europe, however, highlights key differences in short period accelerations resulting from new assumptions regarding the characteristics of the reference rock and its influence on site amplification.

Description: Horizon 2020 Framework Programme http://dx.doi.org/10.13039/100010661

Description: Helmholtz-Zentrum Potsdam Deutsches GeoForschungsZentrum - GFZ (4217)

Description: To complement the new European Strong-Motion dataset and the ongoing efforts to update the seismic hazard and risk assessment of Europe and Mediterranean regions, we propose a new regionally adaptable ground-motion model (GMM). We present here the GMM capable of predicting the 5% damped RotD50 of PGA, PGV, and SA(T = 0.01 − 8 s) from shallow crustal earthquakes of 3 ≤ M W ≤ 7.4 occurring 0 〈 RJB ≤ 545 km away from sites with 90 ≤ Vs30 ≤ 3000 m s−1 or 0.001 ≤ slope ≤ 1 m m−1. The extended applicability derived from thousands of new recordings, however, comes with an apparent increase in the aleatory variability (σ). Firstly, anticipating contaminations and peculiarities in the dataset, we employed robust mixed-effect regressions to down weigh only, and not elimi nate entirely, the influence of outliers on the GMM median and σ. Secondly, we regionalised the attenuating path and localised the earthquake sources using the most recent models, to quantify region-specific anelastic attenuation and locality-specific earthquake characteristics as random-effects, respectively. Thirdly, using the mixed-effect variance–covariance structure, the GMM can be adapted to new regions, localities, and sites with specific datasets. Consequently, the σ is curtailed to a 7% increase at T 〈 0.3 s, and a sub stantial 15% decrease at T ≥ 0.3 s, compared to the RESORCE based partially non-ergodic GMM. We provide the 46 attenuating region-, 56 earthquake localities-, and 1829 site-spe cific adjustments, demonstrate their usage, and present their robustness through a 10-fold cross-validation exercise.

Description: SIGMA2 consortium (EDF, CEA, PG&E, SwissNuclear,. Areva, CEZ, CRIEPI)

Description: H2020 Research Infrastructures http://dx.doi.org/10.13039/100010666

Description: Abstract

Description: This catalogue is the extended version of “The European-Mediterranean Earthquake Catalogue (EMEC) for the last millennium” (Grünthal and Wahlstrom, 2012, 2012a). It is an earthquake catalogue for tectonic events in the broader European Mediterranean area. It reached from the Azores (Mid-Atlantic Ridge) in the west, to Africa north of the Sahara in the south, the Arctic Sea in the north, and the regions of Levant, eastern Turkey, and the Caucasus in the west. This areal coverage gave the name to the catalogue: EMEC—The European-Mediterranean Earthquake Catalogue. It extends the previous version (Grünsthal and Wahlström, 2012), by the years 2007 to 2021 and thus contains tectonic events for the period AD 1000 to 2021 with a uniform magnitude Mw from the threshold of 3.5. The dataset contains 71271 entries.

Description: Abstract

Description: This catalogue is the extended version of “The European-Mediterranean Earthquake Catalogue (EMEC) for the last millennium” (Grünthal and Wahlstrom, 2012, 2012). It is an earthquake catalogue for tectonic events in the area of European Mediterranean, including the Mid-Atlantic ridge down to the Azores, extends in the south to Africa north of the Sahara, in the north to the Arctic Sea, and in the east to the Levant, eastern Turkey, and the Caucasus. This areal coverage gave the name to the catalogue: EMEC—The European-Mediterranea Earthquake Catalogue. It extends the previous version by the years 2007 to 2021 and thus contains tectonic events for the period AD 1000 to 2021 with a uniform magnitude Mw from the threshold of 3.5. The dataset contains 61140 entries.

Description: 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.

Description: 1. Swiss Seismological Service, ETH Zurich, Sonneggstrasse 5, 8092 Zurich, Switzerland, 2. Istituto Nazionale di Geofisica e Vulcanologia (INGV), 00143 Rome, Italy, 3. German Research Centre for Geociences (GFZ), Section 2.6 Seismic Hazard & Risk Dynamics, 14473 Potsdam, Germany, 4. Institut des Sciences de la Terre (ISTerre), IRD, 38058 Grenoble, France, 5. Istituto Nazionale di Geofisica e Vulcanologia (INGV), 20133 Milan, Italy, 6. Instituto Superior Tecnico (IST), 1049-001 Lisboa, Portugal, 7. Bogazici University, Kandilli Observatory and Earthquake Research Institute, Department of Earthquake Engineering, 34684, Cengelkoy, Istanbul, Turkey, 8. Institute of Geophysics , ETH Zurich, Sonneggstrasse 5, 8092 Zurich, Switzerland

Description: Published

Description: OST5 Verso un nuovo Monitoraggio