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Earthquakes

Earthquakes are vibrations caused by rocks breaking and shifting under stress. The effects produced by earthquakes including ground shaking, landslides and rockfalls cause damage to property and loss of life. On a global scale, South Africa is considered a stable region, because it is located away from boundaries between tectonic plates. Therefore its activity rate is lower than in seismically active regions like California or Japan. This means that while earthquakes are comparatively rare, they can still happen from time to time, and sometimes this manifests itself as earthquake swarms.

Earthquake swarms are events where a local area experiences sequences of many earthquakes in a relatively short period of time. Earthquake swarms occur regularly throughout the world and in South Africa an earthquake swarm occurred in the Sutherland area in early 1952, with no further significant activity recorded since. The area of Augrabies has currently been experiencing an earthquake swarm.

The report by Brandt (2011) introduces seismicity and the regional seismicity of Africa and South Africa. The seismic hazard maps for Southern Africa by Fernandez and Du Plessis as well as the South African Seismograph Network and Database are presented.

Reference:
Brandt, M. 2011. Seismic Hazard in South Africa. Council for Geoscience Report Number 2011-0061.

Download the report.

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