Modelling of seismic hazard at the northeastern part of greater Cairo metropolitan area, Egypt

Abstract

The importance of the northeastern part of the greater Cairo metropolitan area is due to the presence of a nuclear power plant and the dense population and its extent towards seismic sources. This paper reviews the likely ground acceleration related to the effective seismic events initiated from the closest seismic sources to the area. For this purpose, a deterministic seismic hazard approach followed by ground stochastic simulation was performed to assess the seismic hazard in the area. Seismic sources of hazardous effects were defined. A controlling earthquake was determined, based upon an empirical relationship between the seismic moment and the rupture length of the fault during the earthquake. The soil amplification characteristics in the area were obtained by in situ ambient noise measurements with great precautions. An H/V technique has been used to estimate the fundamental frequency and amplification factors at the sites of ambient noise measurements. The values of the fundamental frequency and the corresponding amplification factor were estimated at the investigated sites within the area of interest. The maximum possible earthquake magnitude Mmax was estimated for the effective seismic sources surrounding the study area and the hazard parameter peak ground acceleration (PGA) calculated for given zones. The work on the estimation of PGAs will contribute to the determination of national seismic codes, giving guidance on which buildings must take seismic risk into consideration and the necessity to re-appraise the seismic risk for existing buildings.