'Mountain of God' volcano in Tanzania is bulging, study finds

The land around a strange volcano in Tanzania is bulging, suggesting magma may be accumulating in a shallow reservoir beneath the surface. The movement could be a precursor to an eruption, researchers say.

Ol Doinyo Lengai is an active volcano that erupts the runniest lava on Earth. Satellite data indicate that a magma reservoir about 1.4 miles (2.3 kilometers) beneath the crater began swelling in March 2022, suddenly stretching Earth's crust above it. This rapid uplift continued at a steady rate until December 2022, and then gave way to a period of slower uplift that lasted through to August 2023, according to a new study.

Periods of uplift can be signs of an impending eruption, study lead author Ntambila Daud, a doctoral student at Virginia Tech's Geodesy and Tectonophysics Laboratory, said in a statement.

There are records of Ol Doinyo Lengai eruptions going back to the 1880s, and the volcano has been periodically active ever since. "This research could help Tanzanian authorities have a better idea of what is happening with the volcano," Daud said.

It is the only volcano in the world that expels carbonatite lava, which is extremely thin and saturated with alkali elements such as calcium and sodium. Ol Doinyo Lengai, which in the Maasai language translates to "mountain of God," spurts mainly lava flows that turn bone white when they dry. This is due to calcium and carbon dioxide in the lava combining to form calcite and other carbonate minerals that break down quickly in the presence of water or humidity.

Related: Antarctica is covered in volcanoes, could they erupt?

Researchers use satellite data to measure land deformation around volcanoes. In 2016, geoscientists at Virginia Tech installed satellite-connected sensors on the flanks of Ol Doinyo Lengai to monitor the periodic rise and fall of the crust, as well as a seismometer to detect earthquakes.