Earth scientists at the University of Cape Town’s (UCT’s) Department of Geological Sciences have identified a hitherto unknown geological fault underneath the Karoo Basin. This fault extends across the Karoo Basin, running from west-northwest to east-southeast, at a depth varying from 2 km to 12 km. Moreover, this fault seems to be critically stressed, meaning that it can generate earthquakes. This discovery, published in the “Seismological Research Letters”, was made as a result of a study into a swarm of mainly small earthquakes (although one reached a magnitude of 4.8) located near Leeu Gamka, in the Western Cape province, and which started unexpectedly in 2007. So far, at least 66 of these earthquakes have been detected. These earthquakes were all entirely natural.