Ol Doinyo Lengai: The Only Volcano Erupting Superfluid Carbonatite Lava, Has Sunk About 36 cm in the Past Decade.
Ol Doinyo Lengai, located in Tanzania, has been gradually sinking into the Earth over the past ten years, likely due to a magma chamber beneath one of its two craters collapsing, as reported by Live Science on August 2. This new study was conducted by scientists at Pennsylvania State University and published in the journal Geophysical Research Letters.
Ol Doinyo Lengai volcano ejecting superfluid black lava that turns white when dried. (Photo: Jean-Denis JOUBERT/Gamma-Rapho).
Ol Doinyo Lengai is situated on an active rift zone in East Africa. The new research reveals that the ground around the summit of this 2,962 m high volcano has been sinking at a rate of 3.6 cm per year from 2013 to 2023. This means that the volcano has subsided approximately 36 cm over the study period.
The team of experts utilized data from two satellite systems, Sentinel-1 and Cosmo-SkyMed, to map the changes in the ground surrounding Ol Doinyo Lengai over time. The maps indicate that a circular area around the northern crater is shifting away from the satellites at a consistent rate.
Ol Doinyo Lengai is the only volcano on Earth that erupts carbonatite lava – an extremely fluid type of lava rich in alkaline elements such as calcium and sodium, and low in silica. In contrast, most lavas are rich in silica, which is a mixture formed from oxygen and interconnected silicon chains that cause molten rock to become viscous.
“If you had to choose the most unique volcano on Earth, you’d be hard-pressed to find a better candidate than Tanzania’s Ol Doinyo Lengai. The lava erupted from this volcano is one of the strangest things you’ll ever see,” said Erik Klemetti, a volcanologist and associate professor at Denison University in the United States. The lava from Ol Doinyo Lengai produces unusual eruptions resembling a garden hose. Although the lava is black or dark gray when it erupts, it quickly turns white as it dries.
The subsidence of Ol Doinyo Lengai may be due to a magma chamber located 1,000 meters beneath the volcano that is collapsing, according to the research team. They noted that the shape and characteristics of the shallow magma conduit system beneath the volcano remain a mystery, but previous studies have suggested the presence of a shallow reservoir. This reservoir may connect to a larger magma chamber located 3,000 meters or deeper beneath the volcano.
Monitoring the subsidence of Ol Doinyo Lengai is crucial for predicting eruptions. The new study also indicates that there is a 100-meter-long crack filled with lava along the western rim, which may extend further as the volcano continues to erupt and sink.
