Sunday evening Jun-12-2011, with the strongest being two 5.7-magnitude earthquakes which were both centered in Eritrea.

The series of earthquakes began at 6.37 p.m. local time (1537 GMT) when a 5.1-magnitude earthquake struck about 128 kilometers (79 miles) west-northwest of Assab, a port city in the Southern Red Sea region of Eritrea. It struck about 10 kilometers (6.2 miles) deep, making it a shallow earthquake.

The moderate earthquake was followed by seven light earthquakes between magnitudes 4.5 and 4.8 on the Richter scale during the next 2.5 hours. Those were then followed by three earthquakes with magnitudes of 4.7, 4.8, and 5.0.

Soon after, at 11.32 p.m. local time (2032 GMT), a moderate 5.7-magnitude earthquake struck about 123 kilometers (76 miles) west-northwest of Assab at a depth of 10.1 kilometers (6.3 miles)...It estimated that some 18,000 people may have felt moderate to strong shaking as a result of the 5.7-magnitude earthquakes, while 3.6 million others were estimated to have perceived light shaking.

Earthquakes in Africa are rare, especially moderate earthquakes, but similar events have happened before in the region. On July 20, 1884, a strong 6.2-magnitude earthquake struck offshore Massawa, Eritrea. Scores of homes in the region were destroyed but there were no confirmed reports of fatalities.