Ground motion prediction from nearest seismogenic zones in and around Greater Cairo Area, Egypt

doi:10.5194/nhess-10-1495-2010

Abstract

Abstract. This paper reviews the likely source characteristics, focal source mechanism and fault patterns of the nearest effective seismogenic zones to Greater Cairo Area. Furthermore, Mmax and ground accelerations related to the effective seismic events expected in future from those seismogenic zones are well evaluated. For this purpose, the digital waveform of earthquakes than ML=3 that occurred in and around Greater Cairo Area from 1997 to 2008 which have been recorded by the Egyptian National Seismological Network, are used to study source characterization, focal mechanism and fault pattern of the seismogenic zones around Greater Cairo Area. The ground motions are predicted from seismogenic zones to assess seismic hazard in the northeastern part of Greater Cairo, where three effective seismogenic zones, namely Abou Zabul, southeast Cairo trend and Dahshour area, have the largest effect to the Greater Cairo Area. The Mmax was determined, based upon an empirical relationship between the seismic moment and the rupture length of the fault during the earthquake. The estimated Mmax expected from Abou Zabul, southeast Cairo trend, Dahshour seismic sources are of Mw magnitudes equal to 5.4, 5.1, and 6.5, respectively. The predominant fundamental frequency and soil amplification characteristics at the area were obtained using boreholes data and in-situ ambient noise measurement.

Highlights

In Egypt, the population, archaeological sites and sensitive structures are concentrated within a narrow zone around the Nile valley that occupies only 1% of the total area of the country
The importance of the Greater Cairo Area is due to the dense population and it is extending towards the seismic sources
The deterministic seismic hazard assessment in the current study provides www.nat-hazards-earth-syst-sci.net/10/1495/2010/

Summary

Introduction

In Egypt, the population, archaeological sites and sensitive structures are concentrated within a narrow zone around the Nile valley that occupies only 1% of the total area of the country. The economic and social effects of earthquake disasters can be reduced through a comprehensive assessment of seismic hazard and risk for areas such as Egypt. Such a study leads to an increased public awareness, with a consequent upgrading of the existing buildings and engineering works as well as reliable earthquake-resistant designs for new structures. By assuming each of these maximum earthquakes to occur at a location that places the earthquake at the minimum possible distance to the site, the ground motion is predicted, mostly, utilizing an empirical attenuation relation

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Conclusion