Sunday 7 July 2013

Magnitude 4.7 Earthquake in Mpumalanga Province, South Africa.

A Magnitude 4.7 Earthquake was recorded at a depth of 5.0 km, roughly 50 km to the west of Barberton in Mpumalanga Province, South Africa, slightly after 4.50 pm local time (slightly after 2.50 pm GMT) on Sunday 7 July 2013, according to the United States Geological Survey. There are no reports of any damage or casualties, though the quake was felt by people between Nespruit to the northeast and Carolina to the southwest.

The location of the 7 July 2013 Mpumalanga quake. Google Maps.

Earthquakes are rare in South Africa, and this one, if its Magnitude is confirmed (and initial reports are not always reliable), will be the joint third most severe quake ever recorded instrumentally in the country, according to figures from the South African Council for Geoscience (although several pre-instrumental quakes are believed to have been larger).

Because of this rarity it is hard to make precise judgements about the cause of quakes in South Africa, due to a paucity of data. Mpumalanga Province is close to Mozambique, where the southern end of the Great Rift Valley exits the continent and passes out under the Indian Ocean. The Great Rift Valley is slowly splitting the African Plate in two allow a line from the Red Sea through Ethiopia, and which includes the great lakes and volcanoes of east-central Africa. This has the potential to open into a new ocean over the next few tens of millions of years, splitting Africa into two new, smaller, continents; Nubia to the west and Somalia to the east.

However while this could provide a potential cause for the Mpumalanga quake, which is not that distant from the Rift Valley, it cannot comfortably account for tectonic events in Cape Province, where several of the countries largest quakes have been recorded.

Earthquakes in Mpumalanga Province have the potential to be very serious, due to the concentration of mines; the province produces around 83% of all South Africa's coal, as well as precious and base metals and other minerals. Many of the mines in the province are deep pits, which can be particularly vulnerable to Earthquake damage.