High magnitude tremor from last week’s earthquake to rock South Africa


Chris Hartnady, Research and Technical Director at Umvoto Africa, has warned that there are high magnitude tremors expected in the next two weeks, following the earthquake which shook South Africa on the 5th of August.

The high magnitude earthquake, which read 5.5 on the Richter Scale left many traumatized after destroying over 600 houses, injuring 34 people and killing one man.

Last week’s quake, which started in the Stilfontein, Klerksdorp and Orkney region and was felt as far away as Botswana and Mozambique, is the largest earthquake that South Africa has ever experienced in the past decade.  .

Hartnady also said that, although the earthquake was going to happen, mining activities could have accelerated processes responsible for the quake.

“It was waiting to happen at some stage, but the human intervention in the form of mining brought it forward.

“The important thing is that activity like mining, particularly deep mining that disturbs the stress field in these highly stressed areas can trigger quite large events,” stated Hartnady.

He noted that after big earthquake events, there are often smaller tremors or aftershocks that follow, to finish off the process.

"I expect there would be at least two or three magnitude four events coming up within the next week or two,” said Hartnady.

North West Province Premier, Supra Mahumapelo, said they were currently evaluating whether the effects of mining were responsible for last week’s earthquake. 

Michelle Grobbelaar, Manager of the Council for Geosciences, also said that they will be watching the areas for seismicity. She said that they are expecting a tremor at the same 5.5 magnitude but are unable to predict when it will occur.

"The rule of thumb in seismology is that history repeats itself. We can get those magnitudes of 5.5 coming back. We can't say when it will happen but we can expect another one,” said Grobbelaar


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