SEISMICITY OF THE EASTERN MEDITERRANEAN REGION - PERSPECTIVE FROM THESINAI SUBPLATE

We conducted a comprehensive study of the seismicity of the eastern Me diterranean and examined its relation to the regional plate tectonics. Based on various published catalogs, we have constructed a new list o f M(L) greater than or equal to 4 earthquakes which were recorded duri ng the years 1900-1991 and represents most of the seismic moment relea sed in the area over this period. b-values are 1.02, 1.0 and 1.07 for the whole Sinai subplate, the Dead Sea transform and the Cypriot are, respectively. Seismic efficiency of the Dead Sea transform is very low (about 7%!), stressing the role of aseismic deformation in that plate border. Most of the major and moderate events, M(L) greater than or e qual to 5, occur in belts associated with the geologically documented borders of the Sinai subplate: the Cypriot convergent are in the north , the Dead Sea transform in the east and the rift of Suez in the south west (the latter, like the Gulf of Eilat (Aqaba), was considered aseis mic during the first half of the century). The northwestern border, ho wever, could not be delineated. Low-level activity appears within the subplate, especially north of latitude 32 degrees N, reflecting the br eakdown of this part of Sinai as it approaches the Cypriot convergence zone. Though most of the seismic moments tend to concentrate along th e subplate borders, some moderate activity spreads out in wide belts w hich reflect the complexity of deformation accompanying motion along t he subplate borders.