A preliminary probabilistic seismic hazard assessment in terms of Arias intensity in southeastern Spain

A preliminary probabilistic seismic hazard assessment in terms of Arias intensity is presented for the first time in southeastern Spain. In the calculation, the spatially smoothed seismicity procedure has been used, considering four seismic models, and a seismic catalog updated up to 1999. One of the models that include the most significant seismicity, considers earthquakes above 5.5 MS in the last 700 years. or a return period of 475 years, that is, for a 10% probability of exceedance in 50 years, and for different soil conditions, have been computed. The uncertainty in the final result is shown by depicting maps for the mean and mean+σ attenuation curves. Independently of the geological soil conditions, higher Arias intensity values have been obtained along the Betic Cordilleras. The most significant result is the value obtained in the Granada Basin, the most active and hazardous Spanish seismogenic area. It is of the order of 0.4 m/s for shallow soils, 0.3 m/s for deep soils, and 0.2 m/s for stiff rock conditions, for the return period quoted above. These are typical values for a moderate seismic hazard region.