SEISMICITY, TECTONICS AND CRUSTAL DEFORMATION IN RED SEA REGION

Abstract

This work is devoted to use an integrated Global Positioning System (GPS), structural and seismological data for the investigation of recent crustal kinematics and deformations in the seismo-active Red Sea region. The seismological data were used for processing the focal mechanism solutions as a combined solution. Modeling of kinematics and dynamics of active rifting in the Northern and Southern Red Sea is addressed to relevant mechanics of early continental rifting and the current rates of opening across the rift. The Global Positioning System (GPS) observations collected from both Egypt and Yemen are used to measure the present-day styles and rates of extension, as well as rift­ margin deformation along the extent of the Red Sea rift. The GPS campaigns between Egypt and Yemen were measured on April 2000 and November 200I, respectively. Planning, establishing and measurements of these stations were carried out by the author in collaboration with the staff of the National Research Institute of Astronomy and Geophysics (NRIAG), He/wan, Egypt and staff members of the Department of Earth and Environmental Sciences, Sana 'a University, alongwith Geological Survey and Mineral Resources Board, Sana 'a, Yemen.Processing of the collected data played a significant role in understanding and threw much lights on the geodynamical regime of the area, and also in evaluating the general framework of the whole Red Sea region. Analyses of the first and second epoch ofGPS measurements indicate that the magnitudes of the movements, together with the deformational fields of the geodetic points, are small. From the tectonic point of view, this is allributed to the shortness of the period of measurements (only two years). In order to get good results about the crustal movements, repetition of the measurements on the same geodetic points is recommended. It is worthy to mention here that/he magnitudes of movements and the deformational field may reach up to 20 mm in some points close to the Red Sea, such as those in Hodiedah (Yemen) and Dahab (Egypt). This is probably due to the direct effie/ of the spreading movement. Moreover, the directions of movements on these points are relatively opposite to each other. Such results are in harmony with the general/rend of the tectonics in the Red Sea region.