The Erta Ales volcano

Mar 24, 2008 14:19 GMT  ·  By

This is like a wound that never gets closed. In one of the hottest spots of the Earth, in the desert of northern Ethiopia, where even in the winter temperatures vary between 40 to 50oC, the volcano Erta Ale was discovered by the Europeans in 1906. The volcano is active for hundreds of years.

Most volcanoes manifest through occasional eruptions, then their lava hardens, like a crust on a wound. But the wound of Erta Ales does not get closed. 25 Ma ago, a crack emerged between the Arabian and the Ethiopian plates. Even today, the plates move apart one from the other with 0.5cm (0.2in) annually. The fracture formed the Red Sea and the Great African Rift. The only other volcanoes known to have a lake of continuously boiling lava are Puuoo in Hawaii and Erebus in Antarctica.

The depth from the edges of the crater to the lake of boiling lava is of 100m (330ft). The molten lava has a temperature of 1,100-1,200oC. Visitors can approach to 2m (6.6ft) off the lake, as the hot air has the tendency to rise, being replaced by the cold air (of 40-50oC...). At 2m off the edges of the lake, there is a wall of warmth having a temperature of several hundreds degrees Celsius.

The area of the volcano is inhabited by the Afar people (related to Somali). They live from the trade of rock salt, which they extract from surface mines. Thousands of years ago, the region was the bottom of a sea, but the hardened lava closed its access paths. The result was a salty lake that evaporated, leaving behind a layer of salt, up to 3km (1.9mi) thick.

For the Afar nomads, who are Muslims, Erta Ales is a feared and taboo place, being named "The dwelling of the Devil". Along the years, this volcano swells its lava lake before retracting it back. Still, from time to time, the lava overflows the edges of the crater, like in 1974. This dynamic shows that the lake is placed close to the magma reservoir that directly fuels the eruption of a volcano.