Dallol is a volcanic explosion crater (or maar) in the Danakil Depression, northeast of the Erta Ale Range in Ethiopia. It has been formed by the intrusion of basaltic magma in Miocene salt deposits and subsequent hydrothermal activity. Phreatic eruptions took place here in 1926, forming Dallol Volcano, numerous other eruption craters dot the salt flats nearby. These craters are the lowest known subaerial volcanic vents in the world, at over 45 m (150 ft) below sea level. The most recent major activity was in October 2004 when the shallow magma chamber beneath Dallol deflated and fed a magma intrusion southwards beneath the rift.
Numerous hot springs are discharging brine and acidic liquid here. Widespread are small, temporary geysers which are forming cones of salt.
The term Dallol was coined by the Afar people and means dissolution or disintegration describing a landscape made up of green acid ponds (pH-values less than 1) iron oxide, sulfur and salt desert plains. The area resembles the hot springs areas of Yellowstone Park
