© Carsten Peter, National Geographic CreativeAn aerial view shows erosion on Ol Doinyo Lengai volcano, Tanzania.
An active volcano in northeastern Tanzania known to the Maasai as the "Mountain of God" has been quietly rumbling—and it is showing signs that an eruption is imminent.
Known as Ol Doinyo Lengai, the 7,650-foot-tall peak is the only known active volcano that belches out lava rich with a type of rock called carbonatite. This thin, silvery lava can flow faster than a person can run. (Read more about the volcano from our January 2003 issue.)
The volcano is some 70 miles from the city of Arusha and is known for its proximity to some of the world's most important paleoanthropological sites. Ol Doinyo Lengai is less than 70 miles from the famed Olduvai Gorge, a collection of 3.6-million-year-old hominin footprints at a site called Laetoli, and a "dance hall" of ancient Homo sapiens footprints at a site called Engare Sero.
Typically, the volcano's activity is confined to its summit. But occasionally, the Mountain of God can roar to life in more dramatic fashion: On September 4, 2007, the volcano belched out a plume of ash that extended at least 11 miles downwind. Lava running down the north and west flanks ignited burn scars that were visible from space.
Comment: See also: Mount Vesuvius volcano engulfed in smoke as wildfires rage along its slopes in southern Italy