Earthquake hits Kariba, ‘no effect to structural integrity of the dam’

An earthquake of the magnitude M4.3 occurred and was felt in the Kariba and surrounding areas at 22:03 hours on Tuesday, the Zambezi River Authority confirmed.

In a statement on Thursday, the authority said the epicentre was triangulated by the Meteorological Services Department (MSD) of Zimbabwe to approximately 50km South of Kariba Dam near Bumi Hills.

“Although this is a naturally active seismic area, it started experiencing increased seismicity after the filling of Lake Kariba in the 1960s.

“Accordingly, the earthquakes are normal and expected. They are referred to as “reservoir induced tremors” because they are attributed to the presence of the lake,” read the statement.

“In the last twelve months, two earthquakes of equivalent magnitudes and several others of smaller magnitudes occurred south of the Kariba Dam. Of note are magnitude M4.5 and M4.6 earthquakes that occurred on 9 August 2021 and 24 May 2022, with epicentres near Binga and below the Lake respectively.

“We wish to assure the public and those domiciled in and around the affected areas that tremors of this magnitude are not expected to affect the structural integrity of the Kariba Dam.

“We further confirm that there were no unusual observations made from the inspections that were carried out on the morning of 3rd August 2022 nor from the analysis of dam safety data that is collected from several instruments that monitor the behaviour of the dam.”

The Kariba Dam, the largest man-made lake in the world by volume is currently the largest single source of electricity for Zimbabwe.

The Southern African country currently faces acute shortage with demand peaking at 2 200MW, especially during winter, against reliable production of 1 600MW.

The problem is worsened by the Zimbabwe Electricity Supply Authority’s failure to pay for power imports from Zambia and Mozambique.