Deaggregation of probabilistic seismic hazard for selected cities in the Arabian Peninsula

Abstract

Probabilistic seismic hazard assessment (PSHA) for 26 cities in the Arabian Peninsula in terms of unified hazard spectra at rock conditions for 475 and 2475 years return periods was performed. PSHA integrates overall potential earthquake sources with various magnitudes and distances with resulting ground motion prediction intensities. The combination of all these scenarios together cannot inform which particular scenario is most likely contributing to the rate of exceedance of a given ground motion intensity. In order to determine which earthquake contributes most to the hazard, PSHA results are deaggregated for the selected cities based on equal spacing in magnitude and distance for the amplitudes of PGA, SA (T = 0.2 s), SA (T = 1.0 s) and SA (T = 2.0 s) at 2% and 10% probability of exceedance in 50 years (equivalent to 2475, and 475 year return periods, respectively). Seismic hazard at cities close to major active tectonic structures is influenced mostly by earthquakes at nearby distances for both 475 and 2475 years return periods for all considered spectral periods. For cities close to low active seismic sources or relatively far away from the major tectonic elements, the seismic hazard is generally controlled by remote larger earthquakes for long spectral periods and by nearby small to moderate events for shorter ones.