Why Durban felt the quake

Stephen Coan, The Witness

Durban - An earthquake in Durban? Blame it on the beach.

On Tuesday, Durbanites got a taste of the earthquake that registered 5.5 magnitude on the Richter scale at its epicentre in faraway Orkney in North West.

“It was noticed in Durban because the beach sand tends to amplify the ground motion,” said Michelle Grobbelaar, Council for Geosciences Seismology Unit manager, based in Pretoria.

“In Mexico City in 1985, there was an earthquake quite far away but it destroyed parts of the city because it was built on an old lake bed.”

Grobbelaar said the event also felt more prolonged on the coast because this was at the periphery of the earthquake, likening it to an extended wave motion. “At the site of the event you would feel it all in one go. The further away the more you feel.”

Grobbelaar said the earthquake was a “big event” for South Africa and recalled the Ceres, Western Cape, earthquake of 1969 which was also felt across the country.

“It seems the South African geology propagates the movement a lot further.”

Grobbelaar said although the epicentre of Tuesday's earthquake was located in a mining region, it’s “difficult to determine what caused it. We still don’t fully understand the phenomena”.

- The Witness
Read more on: durban earthquakes sa quake
Freedom Gama 2014-08-06 09:50:16 AM
what are those connected to the spiritual world saying? this is where real Prophets should have taken the center stage , not the prophets that only tells you about withcraft
Greg Karpakis 2014-08-06 10:27:56 AM
We felt it on the bluff. Must have something to do with having either sand or rock underground.
Chris Kleynhans 2014-08-06 10:28:22 AM
From this articlke one would believe that the whole of Durban is situated on sand. The movements were even felt in Howick.
Hendry Gabaika 2014-08-06 10:39:37 AM
My dear friend at the North West university did wonders during the quake. He was the first person to stand up in the class, pushed his chair under the table and gotten himself under the chair
Andrie De Lange 2014-08-06 10:41:00 AM
Wrong statement. What about in Botswana Zimbabwe and Mozambique their have experienced similar waves.
Sue Maguire 2014-08-06 10:42:18 AM
Nothing felt on the south coast of kzn.
Giftige Verhoudings 2014-08-06 12:11:57 PM
The REAL reason is because Durban is on the same rift that stretch inland wards to about Orkney and then North to Africa as below. "Africa is literally being torn apart at the seams as we speak; not by war, but by plate tectonics. The east coast of Africa is slowly breaking away from the main body of the continent at the rate of an inch per year as upwelling magma pushes up into the continental crust above, stretching it to the bursting point" basementgeographer.com/east-africa-the-next-continent/
Morgan Mboy Sekgobela 2014-08-06 12:15:19 PM
That's was my question that what's the causes of that tremor?But thanks for further investigation,think u'll let us us know.It seems like in the coastal area the magnitute was higher than we expirienced,Because it has been reduced by 5.2 Magnitute.
Nico van der Merwe 2014-08-06 12:31:27 PM
In 100 million years Nkandla will be on a different continent?
Gaeleen 2014-08-06 12:40:55 PM
ah these comments show stupidity in its prime the rift valley plate is unstable and if it shifts the pressure created has to be released someplace else. in this case it caused a tremor in orkney - we can say thank heavens it didn't wake up a volcano go on line and read about it you all obviously are able to