Fault system at the southeastern boundary of the Okavango Rift, Botswana

The seismically active Okavango Rift in northwestern Botswana is probably t he southern extension of the East Africa Rift System. Relief is low and man y of the geomorphic features of the incipient rift are subtle. The northeas t-southwest trending Kunyere and Thamalakane Faults form the southeastern b oundary of the rift. Proterozoic structural fabrics of similar trend, belon ging to the Ghanzi-Chobe Belt, control the regional trend of the primary Ce nozoic fault set of the rift. Geophysical evidence indicates that these are dominantly normal faults forming boundaries to northeast-southwest trendin g strips of horsts, grabens and halt grabens. Two other major sets trend no rthwest-southeast and north-south. The northwest-southeast set occurs withi n the interfault strips of the major northeast-southwest trending faults. T he latter act as local transfer faults forming boundaries to stress domains within which the secondary northwest-southeast trending faults are produce d. Remote sensing imagery shows a weakly developed north-south set that is spatially associated with, and truncated by the northwest-southeast set. Th e whole fault system probably produces predominantly dip-slip displacements on multiple fault sets responding to a subcontinental east- west extension . (C) 2000 Elsevier Science Limited. All rights reserved.