About to blow? McPhoto/Nilsen/Alamy

IT’S only a matter of time. Scientists studying tremors in east Africa’s rift valley say an eruption from the Ol Doinyo Lengai volcano is imminent. This could threaten ancient hominin footprints preserved at two sites.

The volcano lies 120 kilometres north-west of Arusha in Tanzania. It has erupted three times in the last century, propelling debris and ash high into the air. Increased earthquakes, ash emissions and a widening crack on the west side of the volcano all suggest it will erupt soon, says D. Sarah Stamps at Virginia Tech in Blacksburg.

The volcano is a mere 14.5 kilometres from Engare Sero, where anthropologists recently unearthed over 400 hominin footprints dating back 19,000 years. A large volcanic debris flow could, in theory, swamp the area.


The iconic site of Laetoli, with 3.7-million-year-old hominin footprints, is 113 kilometres away and perhaps safer from harm.

Marco Cherin at the University of Perugia, Italy, is concerned for the Engare Sero prints. “They are amazing for their extraordinary state of preservation,” he says.

“[They’re] not like fossilised bones that we can dig up and walk away with,” says Kevin Hatala at Chatham University in Pittsburgh, Pennsylvania.

Although 3D scans of the prints at both Engare Sero and Laetoli exist, losing either would be a blow. Computer models are “not the same as having the actual site”, Hatala says.