NATIONAL NEWS - The Head of the Archaeology and Geography at Wits University, Professor Gillian Drennan, said the earthquake that originated in the south of Johannesburg could have been a result of the earth readjusting itself.
This comes after the powerful 4.4 magnitude earthquake which originated from the Boksburg area and was felt across large parts of Gauteng in the early hours of 10 June.
Johannesburg residents were shaken awake on Thursday morning by the 2.2 magnitude originating in Soweto.
The Council for Geoscience (CGS) confirmed that Thursday’s earthquake happened at around 03:15AM in the south of Johannesburg.
Soweto earthquake
Drennan told The Citizen that the Soweto earthquake could be the result of the Boksburg incident.
“The one we had a couple of weeks ago was a relatively shallow earthquake and it could have possibly been related to mining activity.
“It could also be related to subsidence, for instance a sinkhole or something like that. Whether it’s because of mining activity, collapse of the ground because of a sinkhole, either way, it’s still the earth readjusting itself,” said Drennan.
Aftershocks
The professor said there are aftershocks after a strong earthquake.
“And if you have one release of shock like that, you should expect aftershocks that can even carry on for a couple of days. So, if you’ve had one, you are likely to have a couple. They all come in groups because the stress builds up so much over the years, and now its just releasing that stress.”
Major earthquake in SA?
Professor Drennan said its very difficult to predict if South Africa will experience a major earthquake with catastrophic consequences.
“We can’t predict. There are multiple reasons for an earthquake. Are we going to see a huge one like the one that destroyed half of Japan? We are not on a plate boundary so we are not going to see that kind of activity.
“But we are moving support underground either because of mining or getting water from underground, so when the earth readjusts, it collapses the ground to close up the empty space. That’s how it does it,” she said.
Pacific Ring of Fire
Drennan explained what a tectonic plate boundary is at the Pacific Ring of Fire.
“The Pacific Ring of Fire is where the Pacific Plate is subducting beneath the adjacent plates around it. So, you got major tectonic activity on that plate boundary.
“We are not on that plate boundary. We are in the middle of a continent, so our kid of readjustment is very different,” she said.
Article: Caxton publication, The Citizen
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