ALBERT

Description: The Aegean region overlies a complex tectonic regime that experiences a wide diversity of earthquake behaviour, with enormous disparity in focal mechanism and spatio-temporal distribution. Multiple random earthquake simulations, via Monte Carlo simulation, offer the opportunity to analyse seismic hazard across the Aegean, whilst still allowing for uncertainty in various parameters such as frequency-magnitude relation, maximum magnitude (Mmax) and attenuation relation. They may also enable meaningful determination of hazard (in terms of Peak Ground Acceleration (PGA) and MSK Intensity) with exceedence probabilities significantly smaller than those currently used in standard probabilistic seismic hazard assessment (PSHA) techniques. In addition, these simulations can also be used to conduct sensitivity analyses that will act as a verification process, allowing assumptions regarding the seismic hazard parameters to be continually tested. A catalogue of earthquakes in the Aegean (1900-1999AD) is used as a basis for fitting appropriate models of spatial distribution, frequency-magnitude relation and maximum-magnitude. This has been achieved by random re-sampling of the catalogue, and by random sampling from a Gutenberg-Richter relation fitted to the observed data. Simple hazard analyses for five cities within the Aegean have been undertaken using the earthquake simulations. PGA has been determined using appropriate attenuation relations, and its variability quantified. For each site, the PGA with a 10% probability of exceedence in 50 years is largely consistent with those of current hazard analyses. This may give the user additional confidence in the hazard determined for lower exceedence probabilities.