Cape Town - An earthquake with its epicentre in the Northern Cape shook Cape Town households during the early hours on Sunday.

Over 200 people in Cape Town recorded their experience with the tremor in an online “Did you feel it” on the US Geological Survey webpage.

The 5.3 magnitude earthquake occurred 101km west of Brandvlei, a small town in the Northern Cape.

The earthquake is believed to have occurred at a depth of 10km at 2.51am.

Residents in Cape Town took to social media to share how the tremor had caused their homes to “shake” and how household items rattled.

In a statement, the Council for Geoscience (CGS) confirmed that the earthquake and an aftershock occurred on Sunday morning at around 2.51 and 5.28, respectively.

“The preliminary results show that the earthquake and aftershock registered local magnitudes of approximately 5.3 and 2.9, respectively, as recorded by the South African Seismograph Network (SANSN).”

The epicentres were located within 20km southwest of Buchufontein in the Northern Cape.

Reports of aftershocks in other parts of the country are being analysed, added CGS.

Eerste River mom Michelle Linnert, 45, described the tremor as both scary and confusing, saying it caused her to question her own sanity.

“I heard the chandeliers in the house rattle and became spooked thinking maybe something supernatural was happening then I heard the dogs barking frantically and realised it must have been something outside. I woke my husband up but he didn’t feel the bed moving.”

Linnert said later that morning she asked her husband if he recalled being woken.

“I asked him, ‘Do you remember I woke you up?’ I was questioning my own sanity and then after he did some research we realised what it was. It was scary.”

Independent geologist Dr Gideon Groenewald, said the quake occurred about 100km north-west of Brandvlei in the Northern Cape and the epicentre was at 10km underground, meaning a deep earth movement.

Groenewald said the intensity was 5.5 on the Richter Scale or about 150 times stronger than a normal thunder clap.

He added that no damage was recorded.

“The earth movement is highly significant because it follows a similar event at Springbok a week ago.

“This might be some indication of earth movement in a very old fault zone in Namaqualand, which is interesting.”

He said earthquakes were rare in South Africa and are mostly associated with mining in the Johannesburg region or with more likely movements in Mozambique.

“These new records are very interesting; 5.5 on the Richter Scale is a significant earthquake and must be noted if repeated in the next six months.”

Professor in the School of Geosciences at the University of the Witwatersrand, Raymond Durrheim, said while earthquakes can be caused or triggered by human activity such as deep mining and filling of large reservoirs, this event in a remote area of the Northern Cape was almost certainly a natural event caused by normal Earth processes.

“Southern Africa is known as a ‘stable continental region’, but that does not mean that earthquakes cannot happen, just that they are less frequent,” he said.

“Southern Africa is affected by the plate boundaries in the centre of the Indian and Atlantic oceans, as well as the East African Rift System, which is slowly splitting the continent. It is also affected by erosion. As the continent is ‘offloaded’, it compensates by rising up, creating stresses and strain in the crust.

“From time to time, the elastic stresses in the crust exceed the strength of the rock, ruptures occur, and the ground shakes.”

He said the epicenter lies in a sparsely populated region, about 100km west of Brandvlei, 170km east-southeast of Springbok, 300km southwest of Upington, and 400km north-northeast of Cape Town.

He said the region was known for swarms and clusters of seismic events.

“There was a M4.3 earthquake on 3 December 2024 near Komaggas that was felt in Springbok. Two events with M>5 occurred in the 1970s.”

Aftershocks are likely, and generally, the largest aftershock would be about one magnitude unit smaller than the main shock.

“The Council for Geoscience reports 10 aftershocks in the 12 or so hours following the M5.3, the largest a M2.3. Aftershocks could continue for weeks or even months as the crust returns to equilibrium.”

He encouraged anyone who felt the quake to complete the CGS earthquake questionnaire, providing disaster managers and scientists with pertinent information: www.geoscience.org.za/ cgs/seismic-events/earth-quake-questionnaire/

Cape Argus