Abstract
An earthquake of magnitude MW 6.5 occurred on the evening of the April 3, 2017 in Central Botswana, southern Africa. Although it is located in the continental interior of the African plate, the seismogenic area was previously considered as a stable region revealing a background seismicity associated with long-term deformation and faulting. The intraplate seismic activity and mainshock area are studied using the database of the Seismotectonic Map of Africa. The mainshock (25.156° E, 22.678° S, 28 km in depth) and aftershocks are located in a sparsely populated national park. The aftershock sequence, which is the largest event of MW 4.5 magnitude, followed the mainshock on the April 5, 2017. The analysis of Sentinel-1 interferogram shows 4–6 cm coseismic surface slip on a NW–SE elongated and ~30 km long surface deformation consistent with the mainshock and aftershock distribution, normal faulting mechanism, and source time function. Here, we study the faulting geometry and rupture characteristics using more than 1000 recorded aftershocks of magnitude ML ≥ 0.5. All seismic events are located at the eastern edge of the Central Kgalagadi Park near the mainshock location in two clear seismicity clusters. The NW–SE trending seismic clusters imply that a segmented fault is the source of these earthquakes, similar to the inferred direction from the normal faulting solution of the main shock. The earthquake rupture geometry results from an active normal fault that agrees with the aftershock locations at surface and at depth and confirms the thickness of ~28 km seismogenic layer.
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Mulabisana, T., Meghraoui, M., Midzi, V. (2022). Seismotectonics of the Khurutse Region, Botswana. In: Meghraoui, M., et al. Advances in Geophysics, Tectonics and Petroleum Geosciences. CAJG 2019. Advances in Science, Technology & Innovation. Springer, Cham. https://doi.org/10.1007/978-3-030-73026-0_7
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DOI: https://doi.org/10.1007/978-3-030-73026-0_7
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