Deterministic scenarios for seismic hazard assessment in Egypt

Abstract

This study is an extension of the previous works in the field of seismic hazard assessment in Egypt with the aim of making the results more accurate and effective, in view of the worst possible scenarios to assess the seismic hazard. The deterministic seismic hazard approach was applied to assess the hazard in Egypt. An updated earthquake catalog of Egypt was prepared and the aftershocks were screened and removed. All the earthquake sizes were unified to the moment magnitude scale. The earthquake catalog was used to identify and locate, accurately, the possible multi-seismotectonic scenarios in and around Egypt. The controlling earthquake was identified from the effective seismic source. Suitable ground motion equations were used to calculate the hazard from each source. Seismic hazard was calculated from each seismic source with the maximum expected earthquake and the shortest distance (worst scenario) from these sources to specific sites all over Egypt distributed on a grid with 0.45° interval. Hazard maps were produced for the peak ground acceleration and for the 0.1, 0.2, 0.5, 1 and 2 s spectral periods for the 50th (median) percentile level for the selected probabilities of exceedance on bedrock condition for various possible seismotectonic models. Finally, the results obtained from the worst case scenarios were compared with the published probabilistic hazard results to ensure the general level of hazard in Egypt.