This map - on the European-Mediterranean Seismological Centre website - shows an earthquake reported 25km south-west of Soweto at 11.14pm. Screengrab: European-Mediterranean Seismological Centre website

Johannesburg - The Council for Geoscience says the earthquake that hit South Africa on Friday morning measured 3.8 on the Richter scale, and not 4.6 as estimated by the US Geological Survey (USGS).

“It's the same event. The USGS measurement is done by a machine, and the stations they use are not in as close proximity to the quake as ours, and that's why it's different,” said council seismology unit manager Michelle Grobbelaar.

“Once they analyse it, it will start changing.”

The USGS said the earthquake occurred 12km west of Orange Farm, a township south of Johannesburg.

However, Grobbelaar said the earthquake hit Carletonville, which is about 70km away, at around 1.14am.

“After that, there were several aftershocks,” she said.

The two major aftershocks were a 3.2-magnitude tremor at 1.15am, and a 2.0-magnitude tremor at 1.16am.

“The other aftershocks were smaller ones,” she said.

Earlier, Johannesburg emergency services spokeswoman Nana Radebe said no injuries were reported and they were not called out to help anyone.

ER24 spokesman Werner Vermaak said they were on standby after the earthquake struck, but they also were not called out.

On August 5, a 31-year-old man was killed in a mining village near Orkney, North West, when a 5.5-magnitude earthquake struck the region.

At least 34 miners were injured, and more than 600 houses were damaged.

At the time, the CGS said more tremors were expected to hit the country in the coming weeks and months.