The seismicity of southern Africa and incipient rifting

Fairhead, J.D.; Henderson, N.

doi:10.1016/0040-1951(77)90133-0

Cited by 77 publications

(29 citation statements)

References 14 publications

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“…From each of these places it propagated along-axis to the north and south to link originally isolated basins (Ebinger, 1989a;Chorowicz, 1992). At present day, the EARS is still propagating southward as shown by distribution of the seismic activity (Fairhead and Henderson, 1977;Fairhead and Stuart, 1982) ( Fig. 19).…”

Section: Rift Propagationmentioning

confidence: 94%

The East African rift system

Chorowicz

2005

Journal of African Earth Sciences

744

472

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Section: Rift Propagationmentioning

confidence: 94%

The East African rift system

Chorowicz

2005

Journal of African Earth Sciences

744

472

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“…Albert, Edouard, Kivu, Tanganyika, Rukwa and Malawi. Furthermore, the region south of the Lake Tanganyika Rift, which includes the Katanga province of south-eastern DRC and northwestern Zambia, is of considerable tectonic interest since geological and geophysical studies have revealed seismically active areas that may be related to the WRA (Mondeguer, 1989;Fairhead and Girdler, 1972;Fairhead and Henderson, 1977;Sebagenzi et al 1993;Shudofsky, 1985). The region is marked by a large negative Bouguer anomaly, a northeast to southwest trending zone of seismic activity (although active fault structures are poorly exposed at the surface), and several young Cenozoic rifts viz.…”

Section: Geology and Seimotectonics Of The Drc And Adjacent Areasmentioning

confidence: 99%

Probabilistic Seismic Hazard Assessment for the Democratic Republic of Congo and Surrounding Areas

Mavonga

Durrheim

2009

South African Journal of Geology

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A probabilistic approach was used to map the seismic hazard in Democratic Republic of Congo and surrounding areas, and assess the seismic hazard level for 14 cities in the region. Seismic hazard maps for 2%, 5% and 10% chance of exceeding the indicated ground accelerations in 50 years were prepared using a homogenised 90-year catalogue compiled for moment magnitudes; the attenuation relations of Mavonga (for the Western Rift Valley of Africa), Jonathan (for eastern and southern Africa) and Atkinson and Boore (for eastern North America); and the EZ-Frisk software package. The highest levels of seismic hazard were found in the Lake Tanganyika Rift seismic zone, where peak ground accelerations in excess of 0.32 g, 0.22 g and 0.16 g are expected to occur with 2%, 5% and 10% chance of exceedence in 50 years, respectively. The seismic hazard in the Congo Basin diminishes with distance away from the Western Rift Valley until, at a distance of about 450 km, the chance of exceeding 0.05 g (the threshold value of engineering interest) is less than 10% in 50 years.

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“…Seismic data from Fairhead and Henderson (1977) show only activity at the Okavango rift and a single event northwest of the Eiseb Block. From the field observation, however, it is clear that tectonic activity has occurred and the displacement of dunes indicates Holocene activity.…”

Section: Regional Correlation and Interpretationmentioning

confidence: 96%

“…The 60 to 70°a nd 120 to 140°orientations are also observed in the Namibian study area, but they are evidently less significant than the 40 to 50°and the 150 to 160°peaks (Figure 4). Reeves (1972) proposed incipient rifting in the Kalahari, and the Okavango Delta has been seen as the southwestern extension of the East African Graben System due to its seismic activities and similar sense of crustal extension (Scholz et al, 1976;Fairhead and Henderson, 1977;McCarthy et al, 1993). East-west extension of the African continent is believed to have reactivated ancient, northeasterly-trending basement structures and the Okavango Delta is interpreted as a large half-graben structure formed by this mechanism (McCarthy et al, 1993).…”

Section: Regional Correlation and Interpretationmentioning

confidence: 96%

The Namibian Eiseb Graben as an extension of the East African Rift: evidence from Landsat TM 5 imagery

Wanke

2005

South African Journal of Geology

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In this study four subparallel faults have been recognised in the Eiseb Block in the field and in Landsat TM 5 scenes. Their extension into Botswana's Gomare and Kunyere faults, which delineate the Okavango Rift/Botswana, has been traced. In the Eiseb Block abrupt termination of Kalahari dunes corresponds with northeast-southwest trending tectonic lineaments, whereas a second set of north-northwest to south-southeast orientated lineaments is evident from the orientation of rivers. The two systems intersect in the central part of the study area. Weighted lineament trends show peaks at northeast to southwest (41°to 50°) and north-northwest to south-southeast (151°to 160°). A field survey revealed small extensional faults of corresponding orientation. The fact that Kalahari dunes are displaced since their last active phase shows that the faulting is post-35 to 28 ka. However, the Eiseb Graben and associated lineaments seem to be a long-lived, probably reactivated structure that follows the pre-existing structures of the Damara inland branch, Karoo trough, and basin structures of the Kalahari.

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The seismicity of southern Africa and incipient rifting

Cited by 77 publications

References 14 publications

The East African rift system

The East African rift system

Probabilistic Seismic Hazard Assessment for the Democratic Republic of Congo and Surrounding Areas

The Namibian Eiseb Graben as an extension of the East African Rift: evidence from Landsat TM 5 imagery

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