 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 45 m (150 ft) or more below sea level.In October 2004 the shallow magma chamber beneath Dallol deflated and fed a magma intrusion southwards beneath the rift.