Histroy of the Zambezi

Seismic activity in Zimbabwe is most active in the Zambezi area. The Zambezi area extends from the northern tip of Zimbabwe, in a south westerly direction through Lake Kariba to the westerly edge of the country. The activity is mainly attributed to reservoir-induded seismicity. There is postulation that pore pressure seems to play a major role in event triggering. Earthquakes of magnitude 5.0 and above in Zimbabwe occur in the Zambezi area except in the southern part of the country that is associated with faulting along the Sabi-Limpopo mobile belt.

The seismic history of the Zambezi area before the existence of the Lake Kariba will remain unknown. There was no monitoring in the area before the reservoir was construted. However, a few events are known to have occured in the area before the dam wall was sealed by December of 1958. An example is an earthquake of surface wave magnitude 6.0 that occurred in the area on May 28, 1910. Such an event supports the existence of natural tectonics and seismic activity in the Zambezi area before the construction of the Kariba dam. It was noted that, events located by, fifty kilometers to the north of Lake Kariba dam were evidence of some natural tectonic activity. In the Zambezi area, activity has remained relatively high.


By courtesy of Dr. A. Makarau (Director Zimbabwe Meteorological Services)