New Generation of Probabilistic Seismic Hazard Assessment for the Area Cologne/Aachen Considering the Uncertainties of the Input Data

A new earthquake catalogue for central, northern and northwestern Europe with unified M sub(w) magnitudes, in part derived from chi-square maximum likelihood regressions, forms the basis for seismic hazard calculations for the Lower Rhine Embayment. Uncertainties in the various input parameters are introduced, a detailed seismic zonation is performed and a recently developed technique for maximum expected magnitude estimation is adopted and quantified. Applying the logic tree algorithm, resulting hazard values with error estimates are obtained as fractile curves (median, 16% and 84% fractiles and mean) plotted for pga (peak ground acceleration; median values for Cologne 0.7 and 1.2m/s super(2) for probabilities of exceedence of 10% and 2%, respectively, in 50years), 0.4s (0.8 and 1.5m/s super(2)) and 1.0s (0.3 and 0.5m/s super(2)) pseudoacclerations, and intensity (I sub(0) = 6.5 and 7.2). For the ground motion parameters, rock foundation is assumed. For the area near Cologne and Aachen, maps show the median and 84% fractile hazard for 2% probability of exceedence in 50years based on pga (maximum median value about 1.5m/s super(2)), and 0.4s (>2m/s super(2)) and 1.0s (about 0.8m/s super(2)) pseudoaccelerations, all for rock. The pga 84% fractile map also has a maximum value above 2m/s super(2) and shows similarities with the median map for 0.4s. In all maps, the maximum values fall within the area 6.2-6.3E and 50.8-50.9N, i.e., east of Aachen.