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

Empirical ground-motion models for point- and extended-source crustal earthquake scenarios in Europe and the Middle East

This article presents the latest generation of ground-motion models for the prediction of elastic response (pseudo-) spectral accelerations, as well as peak ground acceleration and velocity, derived using pan-European databases. The models present a number of novelties with respect to previous generations of models (Ambraseys et al. in Earthq Eng Struct Dyn 25:371-400, 1996, Bull Earthq Eng 3:1-53, 2005; Bommer et al. in Bull Earthq Eng 1:171-203, 2003; Akkar and Bommer in Seismol Res Lett 81:195-206, 2010), namely: inclusion of a nonlinear site amplification function that is a function of V-S30 and reference peak ground acceleration on rock; extension of the magnitude range of applicability of the model down to 4; extension of the distance range of applicability out to 200 km; extension to shorter and longer periods (down to 0.01 s and up to 4 s); and consistent models for both point-source (epicentral, R-epi and hypocentral distance, R-hyp ) and finite-fault (distance to the surface projection of the rupture, R-JB) distance metrics. In addition, data from more than 1.5 times as many earthquakes, compared to previous pan-European models, have been used, leading to regressions based on approximately twice as many records in total. The metadata of these records have been carefully compiled and reappraised in recent European projects. These improvements lead to more robust ground-motion prediction equations than have previously been published for shallow (focal depths less than 30 km) crustal earthquakes in Europe and the Middle East. We conclude with suggestions for the application of the equations to seismic hazard assessments in Europe and the Middle East within a logic-tree framework to capture epistemic uncertainty

Compatible ground-motion prediction equations for damping scaling factors and vertical-to-horizontal spectral amplitude ratios for the broader Europe region

In a companion article Akkar et al. (Bull Earthq Eng, doi: 10.1007/s10518-013-9461-4, 2013a; Bull Earthq Eng, doi: 10.1007/s10518-013-9508-6, 2013b) present a new ground-motion prediction equation (GMPE) for estimating 5 %-damped horizontal pseudo-acceleration spectral (PSA) ordinates for shallow active crustal regions in Europe and the Middle East. This study provides a supplementary viscous damping model to modify 5 %-damped horizontal spectral ordinates of Akkar et al. (Bull Earthq Eng, doi: 10.1007/s10518-013-9461-4, 2013a; Bull Earthq Eng, doi: 10.1007/s10518-013-9508-6, 2013b) for damping ratios ranging from 1 to 50 %. The paper also presents another damping model for scaling 5 %-damped vertical spectral ordinates that can be estimated from the vertical-to-horizontal (V/H) spectral ratio GMPE that is also developed within the context of this study. For consistency in engineering applications, the horizontal and vertical damping models cover the same damping ratios as noted above. The article concludes by introducing period-dependent correlation coefficients to compute horizontal and vertical conditional mean spectra (Baker in J Struct Eng 137:322-331, 2011). The applicability range of the presented models is the same as of the horizontal GMPE proposed by Akkar et al. (Bull Earthq Eng, doi: 10.1007/s10518-013-9461-4, 2013a; Bull Earthq Eng, doi: 10.1007/s10518-013-9508-6, 2013b): as for spectral periods as well as PGA and PGV for V/H model; and in terms of seismological estimator parameters 1,200 m/s, for reverse, normal and strike-slip faults. The source-to-site distance measures that can be used in the computations are epicentral , hypocentral and Joyner-Boore distances. The implementation of the proposed GMPEs will facilitate site-specific adjustments of the spectral amplitudes predicted from probabilistic seismic hazard assessment in Europe and the Middle East region. They can also help expressing the site-specific design ground motion in several formats. The consistency of the proposed models together with the Akkar et al. (Bull Earthq Eng, doi: 10.1007/s10518-013-9461-4, 2013a; Bull Earthq Eng, doi: 10.1007/s10518-013-9508-6, 2013b) GMPE may be advantageous for future modifications in the ground-motion definition in Eurocode 8 (CEN in Eurocode 8, Design of structures for earthquake resistance-part 1: general rules, seismic actions and rules for buildings. European Standard NF EN 1998-1, Brussels, 2004)

Reference database for seismic ground-motion in Europe (RESORCE)

This paper presents the overall procedure followed in order to assemble the most recent pan-European strong-motion databank: Reference Database for Seismic Ground-Motion in Europe (RESORCE). RESORCE is one of the products of the SeIsmic Ground Motion Assessment (SIGMA; projet-sigma.com) project. RESORCE is intended to be a single integrated accelerometric databank for Europe and surrounding areas for use in the development and testing of ground-motion models and for other engineering seismology and earthquake engineering applications. RESORCE aims to contribute to the improvement of earthquake risk studies in Europe and surrounding areas. RESORCE principally updates and extends the previous pan-European strong-motion databank (Ambraseys et al. in Bollettino di Geofisica Teorica ed Applicata 45:113-129, 2004a) with recently compiled Greek, Italian, Swiss and Turkish accelerometric archives. The updates also include earthquake-specific studies published in recent years. The current content of RESORCE includes 5,882 multi-component and uniformly processed accelerograms from 1,814 events and 1,540 strong-motion stations. The moment magnitude range covered by RESORCE is . The source-to-site distance interval extends to 587 km and distance information is given by the common point- and extended-source distance measures. The paper presents the current features of RESORCE through simple statistics that also quantify the differences in metadata and strong-motion processing with respect to the previous version of the pan-European strong-motion databank

Empirical ground-motion models adapted to the intensity measure ASA 40

Relative average-spectral-acceleration (ASA40), a recently developed intensity measure, is defined as the average spectral pseudo-acceleration on the probable interval of evolution of the fundamental frequency of a structure. This article presents two ground motion prediction equations (GMPEs) appropriate for the prediction of ASA40, using a pan-European strong motion database. Taking advantage of the strong correlation between the new intensity measure ASA40 and the spectral pseudo-acceleration (SA), existing GMPEs predicting SA can be adapted to predict ASA40. The first GMPE used in this study is the modified version of a new generation ground motion model, ASB13. In order to decrease the high aleatory uncertainty (sigma) that accompanies predictions when using this modified model, a new model is developed for the prediction of ASA40. Its range of applicability is for magnitudes Mw from 5.5 to 7.6 and distances out to 200 km, it includes site amplification and it is applicable for a range of periods between 0.01 and 4 s. The proposed model decreases the aleatory uncertainty by almost 15 % with respect to the uncertainty of the modified ground motion model