Earthquakes Faults Bounded Rift Basins of South Sudan
[1]
Khalda Yassin Ibrahim, Department of Seismology, Remote Sensing and Seismology Authority, National Center for Research, Khartoum, Sudan.
[2]
Abd Alhafiz Gad El Mula, Department of Geology, Faculty of Science, Khartoum University, Khartoum, Sudan.
The South Sudan rift system extends from the western part of Sudan (south Darfur), through the southern part of Kenya to join the fault system in the Indian. In the South Sudan, earthquake activity is reported from many localities in South Sudan, especially at Jebel El Rajaf, which frequent quakes. This study aims at finding out the relationship between the seismic activity and the faults bounded the rift basins. The gravity data is used to display the configuration of the rift basin which show clearly the existence of a rift in the study area. Four gravity initial models were constructed. These gravity models revealed that the depth of the basins ranges between 2 km to 4.5 km and the width ranges between 38 km to 72 km. The lineament features were created based on the geological map and landsat data. The areal distribution of seismic events is found to be associated with the lineaments in the southern flank of the basins. It will be concluded that the earthquakes in the study area are thought to be caused by the rejuvenation of faults bounding sedimentary basins.
South Sudan, Rift Basins, Earthquakes, Gravity Data, Initial Models, Faults, Landsat Data and Lineaments
[1]
Ambrasseys, N. N., Adams, R. D. 1986. Seismicity of the Sudan. Bulletin of the Seismological Society of America, V. 79, No 2, P. 483-493.
[2]
Babiker, N. M. O., Adel Hakim, H. E., Mula A. H. G and Esawi, A. M..2015. Seismicty and seismotectonics of Sudan and South Sudan. American journal of earth science, V 2, No 5, P. 142-149.
[3]
Browne, S. E., Fairhead, J. D. 1983. Gravity study of the Central African rift system: a model of continental disruption The Ngaoundere and Abu Gabra Rifts, Tectono-physics V. 94, No 1, P. 187-203
[4]
Chapola, L. S. 1997. State of stress in east and south Africa and seismic hazard analysis of Malawi, (Unpub). M.Sc. Thesis, Institute of Solid Earth Physics, University of Bergen, Norway, p. 143.
[5]
Dunkelman, T. J., B. R. Rosendahi and J. A. Karsonc. 1989. Structure and stratigraphy of Turkana rift from seismic reflection data, J. African Earth Sci., 8.489-510.
[6]
Ebinger, C. J. 1989. Tectonic development of western branch of the East African rift system, Geol. Soc. Bull., 101, 885-903.
[7]
http://earthexplorer.usgs.gov
[8]
Hunting geology and geophysics. 1980. Mineral exploration of the Juba area (Unpub report).
[9]
Hunting geology and geophysics Ltd. 1976. Mineral exploration in southern Sudan preliminary survey to establish priority area. Regional Ministry of Commerce, Industry and supply.
[10]
Khalda, Y. I., Mula. A. H. G. 2006. Seismicity of southern Sudan and it’s seismotectonic implication (unpub) M.sc thesis, Sudan Academy of sciences, SAS.
[11]
Mula, A. H. G. 1983. Seismicity and seismotectonics of the Sudan. Paper presented to 13 th colleague in African Geology.
[12]
Mula A. H. G., 1990. Recent earthquake sequence of May 1990 in Juba area Sudan, 278 unpublished report, university of Khartoum.
[13]
Qureshi, I. R., Sadig, A. A. 1967. Earthquakes and associated faulting in central Sudan. Vol 215, No 50 98, pp. 263-265.
[14]
Qureshi, I. R., Mula, H. G. 1971. Two dimensional mass distribution from gravity anomalies: A computer method. Geophys. Prospect, V. 19, No 2, P 180-191.
[15]
Ruff, L., Tichelaar, B., La forge, R. and Sata KE, K. 1990. Movement tensor rate functions for the 5\20\90 Sudan earthquake. Eos, Trans. Am. Geophs. Union, 71 (43): 1441-1441.
[16]
Roland Gaulon. Jean Chorowicz et Barbar Romanowicz. 1991. The south Sudan earthquakes of May – July 1990: evidence of an active intracontinental transforms zone. C. R. Acad. Sci. Paris, t. 312, P. 377-384.
[17]
Rosendahl, B. R. 1987. The architecture of continental rifts with special reference to the East Africa, Ann-Rev. Earth Planet. Sci., 15, 445-503.
[18]
Salama, R. B. 1985. Buried troughs, graben and Rifts in Sudan. Journal of African earth sciences, V. 3, No 3, P. 81-390.
[19]
S. R. I., 1996. Preliminary study of the seismicity of the Sudan. no (2). December. Unpublished report. Seismological Research Institute-Sudan.
[20]
S. R. I., 1996. Catalog of the seismicity of the Sudan for the period 1632-1994. Unpublished report. Seismological Research Institute-Sudan.
[21]
Thomas, J. Schull. 1988. Rift basins of Interior Sudan: Petroleum, Exploration and 293 Discovery. Am. Ass. Bulletin. V. 72. No. 10. P. 1128-1142.
