The earthquake, which struck just before 12:30 was felt from the Free State, to KwaZulu-Natal, Gauteng, North West and Mpumalanga.
The US Geological Survey said the tremor was centred in Orkney, 120 km southwest of Johannesburg, an area with a high concentration of gold mines.
Emergency services across the country were being put on high alert in all metropolitans amid fears of serious injuries after the quake struck apparently near the mining town of Orkney.
TimesLive readers took to Facebook to share their experiences, spanning Johannesburg and Soweto to Centurion and Pretoria, Midrand, Marabastad, Bloemfontein and Upington, and even Durban.
“All the windows of my house are broken because of it,” said Sello Makaveli Naphtally Morudu from Botswana.
Nyiko Nicolaus Mkari wrote, “It just happened in Soshanguve. I was in the library and I saw the whole building shaking. I was almost dead. Thank God!”
“I was just relaxing on my bed and I heard it shaking. I was so scared,” wrote Solly Mayala Gumede from Olifantsfontein.
Lesego Sylvia Mabe said from the Centurion Lake, “I’m on the first floor and felt a terrible shake as if the floor was collapsing”.
Vivian Pitschlitz in Ferndale, Randburg, said “the entire office building felt like it was rocking”.
“At Welkom it was heavy,” reported Sipho Neff Jwili while Kgothatso Mama’lee Phiri from Pretoria central wrote, “I got goose bumps”.
Iris Allen commented, “We felt it quite strongly in Potchefstroom. Took me totally by surprise – did not know we got them here!”
Jeanette Bergoff on the East Rand was overwhelmed, saying: “My chair was shaking and I could feel it through the soles of my shoes. I felt quite ill as it was happening. Pictures shaking on the walls, cupboard doors opening and closing. Quite bizarre. I literally felt the roof rattling as well. I have never experienced anything like this”.