A. El-Sayed, R. Wahlstr & O. Kulh nek (Seismological Department, Uppsala University Box 2101, S 750 02 Uppsala, Sweden)

Egypt has been shaken by several destructive earthquakes in both historical and recent times from distant and near earthquakes. The interaction of the African, Arabian and Eurasian plates, and the Sinai subplate, is the main factor behind the seismicity of Egypt. Earthquakes in Egypt occur at shallow depth and are concentrated to four seismic zones. The annual energy release is equivalent to an earthquake with mb varying from 4.5 to 7.0. Periods of high activity have a short recurrence time period, approximately 10 years.

In Egypt, both small local and large distant earthquakes have caused huge damage. Poor building quality, low preparedness, shallow focal depth and local geological conditions are main factors contributing to the earthquake damage. Loose soft sediments amplify the peak ground acceleration by a factor of two. Water-saturated sediments causing liquefaction add to the earthquake damage. Highly populated cities, sensitive structures and archeological sites are located on a soft, water-saturated sedimentary ground. The expected peak ground acceleration in these areas in 50 years exceeds 0.1g.