DISTRIBUTION OF THE ENERGY-RELEASE, B-VALUES AND SEISMIC HAZARD IN EGYPT

A review of the seismicity and seismic history of Egypt indicates area s of high activity concentrated along Oligocene-Miocene faults. This s upports the idea of recent activation of the Oligocene-Miocene stress cycle. There are similarities in the spatial distribution of recent an d historical epicenters. Destructive earthquakes in Egypt are mostly c oncentrated in the highly populated areas of the Nile Valley and Nile Delta. Some big earthquakes located near the plate boundary as far awa y as Turkey and Crete were strongly felt in Egypt. The distribution of the energy release shows a possible tectonic connection between activ e zones in Egypt and the complicated tectonic zones in Turkey and Cret e through geologically verified fault systems. The distribution of int ensity shows a strong directivity along the Nile Valley. This is due t o the presence of a thick layer of loose sediments on top of the hard rock in the Nile Valley graben. The distribution of b-values indicates two different zones, comparable with stable and unstable shelf areas. Stress loads in the northern Red Sea and northern Egypt are similar. Geologically, northern Egypt is a part of the Unstable Shelf area. The probability to have an earthquake with intensity V or larger within 9 4 years is more than 80% in the Nile Valley and Nile Delta areas, Egyp t-Mediterranean coastal area, Aswan High Dam area, Gulf of Aqaba-Levan t Fault zone and in the oil fields of the Gulf of Suez, The maximum ex pected intensity in these areas and within the same period is V-VI for a 80% probability and VII-VIII+ for a 10% probability. Intensity VIII -IX has been reported for several earthquakes in both historical and r ecent time.