Crustal Deformation Associated with the Earthquake Activity at Dahshour Area, Southwest Cairo, Egypt

On 12^th October 1992 the Cairo city in Egypt was hit by an earthquake with a magnitude of mb=5.8. This earthquake occurred at Dahshour area, 35 km southwest of Cairo. Monitoring of recent crustal movement by the Global Positioning System (GPS) is carried out during the period 1999-2003 in the epicentre area. The tectonics as well as seismotectonics of Dahshour area is investigated. Three seismogenic faults that trend E-W, NW-SE and NE-SW affect the area. A11 these faults are nonnal faults; tensional stresses are predominant. The results obtained from the GPS measurements show significant horizontal movements during the period of observation about 8mm/year. The observed horizontal movements are comparable with the tensional stress obtained by fault plane solutions of earthquakes. The extensional and compressional strains are estimated to be +0.4 and -0.2 microstrain/y.