الفهرس 
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Abstract
In this work, we converted the various reported magnitudes into moment magnitude, using multi-step approach. To do that, we chose the most frequently reported magnitude types that provide satisfactory regressions. This is the only possible solution to obtain a uniform magnitude type. The moment magnitude calculated from the other magnitude types may be considered complete for Mw > 4.5 during the period from 1900 until 1984 and for Mw >3.0 during the recent period (1985-2004) for the unified catalogue. We selected 239 focal mechanisms from 301solutions covering the magnitude range 2.3-7.2, It is convenient to note, the strong priority has been given to solutions based on waveform inversion collected either from published studies or international bulletins.The focal mechanism catalogue does not reflect a simple uniform pattern of seismic dislocation and numerous distinct stress zones can be delineated. The inversion of data set respective to the six separate sub-regions indicates a prevailed tension stress (σ3 horizontal) along the NE African corner, which is in agreement with that of Bosworth and Taviani (1996), and the new tectonic study of Abu Elenean (2008).The normal faulting regime, such as along the Suez-Aqaba-northern Red Sea rifts, the horizontal component of slip (or opening) is inferred to be regionally in the direction of the least principal stress. The inversion of separate sub-regions shows horizontal plunge of σ3 with trends SW-NE (northern Gulf of Suez) or NE-SW (southern Gulf of Suez) to SSW-NNE (for the three onland sub-regions) and ENE for Gulf of Aqaba.These regimes are compatible with the kinematics of the Red Sea-Gulf of Suez rift and Gulf of Aqaba transform plate boundary. Furthermore, the recent interpretation of North African stress fields (Bosworth, 2008) is similar to the present study (Shmin directed N-S) for the Cairo-Suez, Dahshour, and Aswan areas. This stress field is in good agreement with general trend of the regional stress field in central Africa intraplate which continuous west into Libya and south into Sudan and the Congo basin. This is attributed to the far-field effects of ridge-push in the Atlantic and Indian Oceans, The African plate is bounded on the west by the South and Central Atlantic Ridges and on the east by the Indian Ocean Ridges. These spreading centres produce ridge-push compressive forces that place Central Africa in an overall state of E-W compression (Zoback, 1992; Ayele, 2002),