Network of European Research Infrastructures for Earthquake Risk Assessment and Mitigation(NERA)

The overall aim of NERA is to achieve a measurable improvement and a long-term impact in the assessment and reduction of the vulnerability of constructions and citizens to earthquakes. NERA will integrate the key research infrastructures in Europe to monitor earthquakes and assess their hazard and risk, and will combine expertise in observational and strong-motion seismology, modeling, geotechnical and earthquake engineering to develop activities to improve the use of infrastructures and facilitate the access to data. NERA will ensure the provision of high-quality services, including access to earthquake data and parameters and to hazard and risk products and tools. NERA will coordinate with other EC projects (SHARE, SYNER-G) a comprehensive dissemination effort. NERA will contribute to the OECD GEM program and to the EPOS ESFRI infrastructure.EU, Funded under :FP7-INFRASTRUCTURES-2010-

Seismic Hazard Harmonization in Europe (SHARE)

SHARE will deliver measurable progress in all steps leading to a harmonized assessment of seismic hazard – in the definition of engineering requirements, in the collection and analysis of input data, in procedures for hazard assessment, and in engineering applications. SHARE will create a unified framework and computational infrastructure for seismic hazard assessment and produce an integrated European probabilistic seismic hazard assessment (PSHA) model and specific scenario based modeling tools. The SHARE results will deliver long-lasting structural impact in areas of societal and economic relevance, they will serve as a reference for the Eurocode 8 application, and will provide homogeneous input for the correct seismic safety assessment for critical industry, such as the energy infrastructures and the re-insurance sector. SHARE will cover the whole European territory, the Maghreb countries in the Southern Mediterranean and Turkey in the Eastern Mediterranean.EU, Funded under :FP7-ENV-2008-

Compilation and critical review of GMPEs for the GEM-PEER Global GMPEs Project

International audienceGround-motion prediction equations (GMPEs) relate a ground-motion parameter (e.g. peak ground acceleration, PGA) to a set of explanatory variables describing the source, wave propagation path and site conditions. In the past five decades many hundreds of GMPEs for the prediction of PGA and linear elastic response spectral ordinates have been published. We discuss the pre-selection of GMPEs undertaken within the framework of the GEM-PEER Global GMPEs Project. The pre-selection criteria adopted were consistent with the current state-of-the-art in ground-motion characterization and sought to retain only the most robust GMPEs. Consideration of broad tectonic regionalization (e.g. shallow crustal seismicity in tectonically-active areas, stable continental regions and subduction zones) was made but it was assumed (based on previous studies) that strong regional differences were not present within these tectonic classes. In total about thirty GMPEs were pre-selected for closer inspection and testing to obtain a final set of ground-motion models

Defining a consistent strategy to model ground-motion parameters for the GEM-PEER Global GMPEs project

International audienceThe project entitled Global Ground Motion Prediction Equations is funded by the Global Earthquake Model (GEM) Foundation and has the objective of recommending a harmonized suite of ground motion prediction equations (GMPEs) that can be used at the global and regional scales for seismic hazard analysis and loss estimation studies. As part of this project, Task 1a experts were commissioned to make recommendations on the critical aspects of seismological predictor parameters that are used by predictive model developers to estimate ground motions for different earthquake scenarios. It is hoped that these recommendations would lead to the optimum description of ground-motion models that can be used efficiently for reliable seismic hazard assessment studies

Toward a ground-motion logic tree for probabilistic seismic hazard assessment in Europe

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 hazar

RESORCE (Reference database for seismic ground motion in Europe)

With the aim of improving seismic ground-motion models in Europe and reducing associated uncertainties, the compilation of a high-quality database of seismic-motion recordings and associated metadata is of primary importance. SIGMA research and development project, devoted to the improvement of seismic hazard estimates, methods and data for France and nearby regions, has been funding the implementation of RESORCE (Reference databaSe fOR seismiC ground-motion in Europe, Akkar et al., 2014)

Towards a uniform earthquake risk model for Europe

Seismic risk has been the focus of a number of European projects in recent years, but there has never been a concerted effort amongst the research community to produce a uniform European risk model. The H2020 SERA project has a work package that is dedicated to that objective, with the aim being to produce an exposure model, a set of fragility/vulnerability functions, and socio-economic indicators in order to assess probabilistic seismic risk at a European scale. The partners of the project are working together with the wider seismic risk community through web tools, questionnaires, workshops, and meetings. All of the products of the project will be openly shared with the community on both the OpenQuake platform of the Global Earthquake Model (GEM) and the web platform of the European Facilities for Earthquake Hazard and Risk (EFEHR)

The European Seismic Risk Model 2020 (ESRM20)

This study describes the development of the various components of the European Seismic Risk Model 2020 (ESRM2020) which will be able to generate, using open-source software developed by the GEM Foundation (the Open Quake-engine), a number of Europe-wide risk metrics including average annualised human and economic losses (AAL), probable maximum losses (PML), and risk maps showing the losses for specific return periods or scenario events. The latest developments towards pan-European exposure models for residential and non-residential buildings and fragility/vulnerability models for damage, economic loss and casualty assessment will be presented. For engineered buildings within the exposure model (reinforced concrete, steel), a simulated design is undertaken using the key aspects of seismic design codes in force across Europe over the past 100 years. The designed MDOF building is then transformed to a SDOF model and nonlinear dynamic analyses are run using a large number of ground motion records, after which cloud analysis is used to develop the fragility functions. For non-engineered buildings (unreinforced masonry, confined masonry, adobe), the SDOF models have been directly developed from simplified formulae, experimental tests and previous studies. Collaboration from local experts at various stages of the model development, initiated through workshops, is an important component of the model, as well as the extensive calibration and validation

Comparisons among the five ground-motion models developed using RESORCE for the prediction of response spectral accelerations due to earthquakes in Europe and the Middle East

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