BY NOKUTHABA DLAMINI
The area around the Kariba Dam was hit by an earthquake on Tuesday, but he authorities say it is nothing out of the ordinary.
The Zambezi River Authority (ZRA) played down the phenomenon as normal and referred to the earthquake measuring M4.3 “as load-induced, or reservoir-induced tremors.”
The epicentre was triangulated by the Meteorological Services Department (MSD) of Zimbabwe to approximately 50km South of Kariba Dam near Bumi Hills and struck at 22:03 hours.
“In the last 12 months, two earthquakes of equivalent magnitudes and several others of smaller magnitudes occurred south of the Kariba Dam,” ZRA said in a press statement.
“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.
“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.
ZRA, which is a bi-national organisation mandated to provide water for generation of electricity in Zambia and Zimbabwe, said no anomaly was reported at the dam following the earthquake.
“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,” it said.
“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 MSD said although no reports of damage were received, more enquiries would be made to determine its intensity in the locality and to determine the exact areas it was felt.
“This region extends from the northern tip of the country, in a south-westerly direction through Lake Kariba, Devil’s Gorge, the Deka Fault, to the westerly edge of the country,” MSD said.
The Bumi Hills Anti-Poaching Unit said elephants could be heard continuously rumbling looking for each other after the tremors.