Nyiragongo hosts within its crater the world’s largest continuously active lava lake, which scientists concluded in their observation that it was filling at an alarming rate.
This year in February, Dario Tedesco, a volcanologist at the Luigi Vanvitelli University of Campania in Italy, led a team to collect data from the volcano’s summit crater.
They concluded that since the February 2016 intra-crater event, the crater floor level has been rising much faster than during the 2010-2016 period.
The current activity, they said, is reminiscent of the 1970-1972 and 1994-1995 periods preceding the lava lake drainage events in 1977 and 2002.
During the last event, the lava flowed within the city of Goma in DR Congo and caused major socioeconomic disruption by killing 250 people and destroying more than 80 per cent of the economic infrastructure.
It also left 120,000 people homeless, most of whom fled to Rwanda’s side of Gisenyi, which borders Goma in the Eastern Democratic Republic of Congo (DRC).
However, Jean-Claude Ngaruye, a geologist, says the predicted next eruption may not have a grave impact on Rwanda’s side.
“Based on past historical events, I don’t see the predicted eruption having any big impact on Rwanda. This is because Rubavu (which shares Nyiragongo with Goma) is situated in a valley,” he said.
The Mining Exploration Division Manager at the Rwanda Mines, Gas and Petroleum Board (RMB) added that the eruption, however, could affect Lake Kivu in one way or another.
“Still, past events do not show any evidence that Lake Kivu, specifically on Rwanda’s side, was affected,” he noted.
The last eruption occurred in 2002, and it began after an earthquake opened up cracks in the southern flank of the volcano.
The 200-meter-wide lava lake drained in a matter of hours, releasing low-silica, runny lava that flowed as fast as 60 kilometers per hour.
The lava then piled up in layers up to 2 meters deep in Goma and created a new delta 800 meters wide in nearby Lake Kivu.
As soon as the fissures healed, however, fresh lava began to bubble up and refill the Crater Lake. Activity accelerated in 2016 when a second vent began to fountain within the crater.
In February, on their most recent inspection, Tedesco and his colleagues found the lake rising faster than ever.
The second hole was gushing an estimated 4 cubic meters of lava per second, enough to fill an Olympic swimming pool every 10 minutes.
They expect the lava lake to stop rising soon, in which case the period of peak danger for Goma would be from 2024 to 2027.
Dr Digne Rwabuhungu, another geologist and the Dean of University of Rwanda’s School of Mining and Geology, believes there are many implications of a possible eruption.
“Even the fact that it could create a wave of refugees from Goma city to Gisenyi city is a big implication. But the big impact could be when the lava reaches Lake Kivu,” he said.
During the last eruption in 2002, Rwabuhungu was pursuing his studies in Belgium. He and his colleagues were brought in to examine what could happen next.
“Our fear at a time and the big question we had was what would happen to Lake Kivu, because we knew that when the lava flowed to Lake Kivu it would destablise the stability of the lake,” he recalled.
However, the fluidity – the speed and temperature – of the lava at a time was not too rapid.
Rwabuhungu still fears that when the rising level of the lava lake on Nyiragongo creates a fracture it would allow the lava or magma to flow into Lake Kivu, which would cause a catastrophic event.
“That risk is not yet evaluated yet,” he told The New Times.
Currently, Goma Volcano Observatory (GVO) is the only monitoring station of Nyiragongo and the impact of eruptive activities in the region.