RELATIONS BETWEEN NORMAL-FAULT GEOMETRY, TILTING AND VERTICAL MOTIONS IN EXTENSIONAL TERRAINS - AN EXAMPLE FROM THE SOUTHERN GULF OF SUEZ

Earthquakes and data from subsurface oil exploration suggest that large active normal faults in the southern Gulf of Suez are approximately planar with dips of 30-40 degree from the surface to around 10 km depth. These faults, appear to rotate about a horizontal axis as they move, causing tilting. The absolute amplitude of the vertical motions can be approximately modelled by planar rotating normal faults that impose a saw-tooth topography on a regional subsidence caused by crustal and lithospheric thinning. The observations required for this simple model are the present day fault dip, the amount of tilting and the width of the rotating blocks.