Active faults in West Africa |
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| Authors: | DJ Blundell |
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| Institution: | Department of Geology, Chelsea College, University of London Great Britain |
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| Abstract: | Interpretation of offshore seismic surveys south of Accra, Ghana, has shown that Accra is situated near the intersection of the northeast-trending Akwapim fault zone and an east-trending coastal boundary fault. Seismic recordings from Kukurantumi Observatory and historical evidence of earthquakes indicate that both faults are currently active. This is also supported by geological evidence. The Akwapim fault is traced southwest across the continental shelf to link at the margin with the Romanche fracture zone on which there is evidence of tectonic activity beyond the confines of the offsets of the Mid-Atlantic Ridge. It is suggested that current tectonism along the Romanche fracture zone continues deep into the continent along the Akwapim fault zone and may represent an early stage in the development of a new plate boundary. Possibly the initiation of this boundary is through crustal fault propagation rather than rifting, perhaps by the mechanism of membrane tectonics proposed by Turcotte and Oxburgh (1973). |
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