ALBERT

Beschreibung: In the frame of the European Commission project "Seismic Hazard Harmonization in Europe" (SHARE), aiming at harmonizing seismic hazard at a European scale, the compilation of a homogeneous, European parametric earthquake catalogue was planned. The goal was to be achieved by considering the most updated historical dataset and assessing homogenous magnitudes, with support from several institutions. This paper describes the SHARE European Earthquake Catalogue (SHEEC), which covers the time window 1000-1899. It strongly relies on the experience of the European Commission project "Network of Research Infrastructures for European Seismology" (NERIES), a module of which was dedicated to create the European "Archive of Historical Earthquake Data" (AHEAD) and to establish methodologies to homogenously derive earthquake parameters from macroseismic data. AHEAD has supplied the final earthquake list, obtained after sorting duplications out and eliminating many fake events; in addition, it supplied the most updated historical dataset. Macroseismic data points (MDPs) provided by AHEAD have been processed with updated, repeatable procedures, regionally calibrated against a set of recent, instrumental earthquakes, to obtain earthquake parameters. From the same data, a set of epicentral intensity-to-magnitude relations has been derived, with the aim of providing another set of homogeneous Mw estimates. Then, a strategy focussed on maximizing the homogeneity of the final epicentral location and Mw, has been adopted. Special care has been devoted also to supply location and Mw uncertainty. The paper focuses on the procedure adopted for the compilation of SHEEC and briefly comments on the achieved results. © 2012 The Author(s).

Beschreibung: Data from European earthquakes in the magnitude range 5 to 8 between 1905 and 1992 have been collected and collated, for distances between 200 and 3400 km. The data include both analog and digital records, with priority on wave paths traversing northern Europe. Historical analog records from Uppsala and De Bilt have been digitised, and appropriate response functions established. New estimates of seismic moments and moment magnitudes have been obtained, which together with moment magnitudes from other sources have been compared to surface wave magnitudes. The location of the largest north European earthquakes substantiate earlier suggestions that rifted regions (passive margins, rifts and grabens) may have the largest seismic potentials. A random-vibration (stochastic) model for prediction of observed peak amplitude, period and Fourier acceleration spectra has been developed and calibrated against intermediate and long-period observations. Reasonably good correspondence between predictions and observations are obtained when using a simple Brune source spectrum, new values for seismic moments and moment-magnitude relations, together with reasonable assumptions for stress drop, geometrical spreading and anelastic attenuation. The model is useful first of all for predicting broad regional averages, but as such it is robust, and it also has the potential to be used in an engineering context for predicting spectral response and peak ground accelerations. Some of the empirical data have also been studied in terms of pseudo-relative spectral velocity and compared to strong-motion response spectral prediction models established for northwestern Europe, again for low frequencies. Irrespective of these prediction models we emphasize, however, that the establishment of the data base itself has been an independent and important purpose of this study.