Buildings shook, bottles and cans fell from supermarket shelves, and people screamed and rushed outside during the earthquake which was felt over wide areas of South Africa and beyond at lunchtime on Tuesday.
Scientists warned that further earth movements could take place, and on Tuesday night an aftershock hit the township of Khuma, near Orkney, a mining town near Klerksdorp in North West, which was the epicentre of the earthquake.
People who had gathered outside one of the houses that was destroyed screamed as the ground shook again.
Emergency personnel who were removing belongings from the house evacuated the yard.
Families in North West suffered the most extensive damage to their homes and a 31-year-old man died when a wall collapsed on him.
At least 17 people were injured and hundreds of houses were affected.
The earthquake happened just after 12.20pm and was felt in Gauteng, KwaZulu-Natal, the Free State, Lesotho, Zimbabwe, Botswana and Mozambique.
The US Geological Survey initially reported the quake as measuring 5.3 on the Richter scale. However, the Council for Geoscience in SA later put the final measurement at 5.5. The council said the discrepancy could have been a result of the US using a different scale for measuring.
“For South Africa, a 5.5 magnitude quake is quite big, but it’s not uncommon,” said Herman van Niekerk, a structural geologist from the University of Johannesburg.
“It went on for about 20 seconds or so, but some people say they felt it for a lot longer.”
The quake was one of South Africa’s largest-magnitude earthquakes in the past decade.
The Council for Geoscience’s Michelle Grobbelaar said more tremors, aftershocks and possibly a second quake of the same magnitude were expected in the coming days.
“More tremors are expected. We can expect one of the same magnitude in future, we just don’t know when. We cannot predict.”
ER24 spokeswoman Luyanda Majija said the body of a man was found in an old mining village in Orkney.
“He was found lying under some debris.”
Majija confirmed that there were no miners trapped in mines around Orkney.
“Most miners working in various mines have been brought out,” she said.
According to AngloGold Ashanti, 17 employees at its Vaal River operations were injured.
“Early indications are that 17 of our employees at the Great Noligwa and Moab Khotsong mines sustained minor injuries and are being attended to on site by emergency medical staff,” it said.
Joburg emergency services spokesman Robert Mulaudzi said the quake was felt in most parts of the city.
In Tshwane, the offices of the public protector and two buildings at the University of Pretoria were evacuated.
Free State police spokesman Captain Steven Thakeng in Thabong and Welkom said pupils were evacuated from schools as a precaution.
In Ventersdorp, about 55km from Potchefstroom, resident Solomon Mere said he was at work when they heard a strange sound.
“It was as if something heavy was coming. We left our office and rushed into the street to see it.
“We could not see anything and suddenly the earth vibrated under our feet,” he said.
Expert opinion was divided on the cause of the quake.
Van Niekerk said it was an indication that the earth’s crust was under stress.
One of the “stresses” could be what was happening in the Great Rift Valley, in the north of Africa.
Van Niekerk said he did not believe that mining was to blame for the quake.
But Professor Andrzej Kijko, director of the University of Pretoria’s Natural Hazard Centre, saw the cause as mining-related.
He said there were two types of seismic events in South Africa, those that were mining-related and those that occurred naturally.
Kijko said the natural events did not occur often in South Africa.
The largest one hit in 1969, in Ceres, not far from Cape Town, and registered 6.3 on the Richter scale.
“Ninety-five percent of the events here are mining-related and they’re usually not very strong,” he said, adding that for a mining-related event, Tuesday’s tremor was big.
“In a place like Klerksdorp, you mine in a flock and you accumulate stress (to the earth) and that triggers natural stresses, which lead to tremors,” Kijko said.
What to do during quake:
What is the Richter scale?
The Richter scale is a standard scale used to compare quakes. It is a logarithmic scale, meaning that the numbers on the scale measure factors of 10. This means, for example, that a quake which measures 4.0 on the Richter scale is 10 times larger than one that measures 3.0. – Source: HowStuffWorks
Additional reporting by Vuyo Mkize