BOTSWANA has been rocked by what appears to be its strongest ever earthquake - just hours after South Africa was also struck. This afternoon's earthquake has measured 6.8 on the Richter scale - a rare strong quake for Africa. It is unknown whether much damage has been caused by the quake, which occurred at around 5.40pm local time (6.40pm GMT) at a depth of around 35km. Luckily the quake's epicentre struck an area with few inhabitants. Users took to the Earthquake Report website to express their shock and describe their experience. One, writing from the city of Letlhakane, said: "We felt the house was vibrating, all the window and door panels shaking heavily. "We went outside and felt the same." A second, writing from Gaborone, said: "It wz very scary but there was no damage" Another resident of the southern African country's capital said: "So frightened." Quakes of this size are rare in Botswana, with geological experts saying it could be historically large. LastQuake said: