TOWARDS SEISMIC ZONATION OF SUDAN

Sudan, the largest country in Africa, because of its size and stretch, has diverse geologic and tectonic structure. Although Africa has been relatively seismically inactive, the East African Rift with its several branches pass through Sudan, has experienced one of the largest earthquakes in the world in recent years. The May ۲۰, ۱۹۹۰, ۷.۴ earthquake and its after shocks that hit Southern Sudan is one of the largest in continental Africa in the instrumental era of earthquake recording. In addition, there is a noticeable increase, recently, in seismic activities in the Nile Basin which covers most of Sudan, This basin did not experience such increase in earthquake's intensity and frequency for very long period of time.This paper addresses the first topic of seismic macrozonation of Sudan. Such study will give design engineers an idea about earthquake prone areas and help them in determining the design earthquake, selecting sites for large structural projects and planning for land use for urban and regional development. Although microzonation is also a key factor in such issues, however, it is a subject of another ongoing research. Therefore, the paper presents the seismicity of Sudan from ۱۸۵۰ to ۱۹۹۳, describes the nature and characteristics of known rifts and faults in Sudan and gives suggestions for seismic zonation of Sudan based on peak ground acceleration and earthquake intensity. Several maps of Sudan and the surrounding region is presented.