A scientific campaign set to assess the status of Nyiragongo's crater found that current conditions at the volcano suggest that peak hazard will arrive in 4 years, or earlier if an earthquake were to hit the volcano. Nyiragongo's current eruptive phase started in May 2002.
The volcano is located in the Virunga Volcanic Province (VVP) in the Democratic Republic of the Congo, part of the western branch of the East African Rift System.
It has a 1.2 km (1.9 miles) wide summit crater with a prominent lava lake, at times the most voluminous lava lake in recent history, that has been active since at least 1971.
When Nyiragongo erupted in January 2002, lava flows inundated portions of the major city of Goma (population in 2020 634 000), located 16 km (10 miles) S of the crater.
20% of the city was destroyed when the volcano erupted, an estimated 250 people died and hundreds of thousands evacuated.
Aerials of lava flowing through the city and into Lake Kivu
Since then, the at-risk population living in the shadow of the volcano has more than doubled to 1.5 million, researchers said, adding that conditions now are ripe for another disaster.
Campaign leader Dario Tedesco -- a volcanologist at the Luigi Vanvitelli University of Campania -- and his colleagues found the lava lake there filling at an alarming rate, faster than ever before.
The analysis suggests the peak hazard will arrive in 4 years, although researchers believe an earthquake could trigger a crisis earlier.
Tedesco said he is alarmed by parallels to the 2002 eruption, which began after an earthquake opened up fissures in the southern flank of the volcano.
The then largest lava lake in the world drained in a matter of hours, releasing low-silica, runny lava that flowed as fast as 60 km/h (37 mph), Rolan Pease noted in his report published in Science.
The lava piled up in layers up to 2 m (6.5 feet) deep in Goma and created a new delta 800 m (2 624 feet) wide in nearby Lake Kivu.
Nyiragongo and Goma, DR Congo on September 19, 2020. Credit: Copernicus EU/Sentinel-2
Activity at the volcano accelerated in 2016 when a second vent began to fountain within the crater, gushing an estimated 4 m3 (141 ft3) of lava per second, enough to fill an Olympic swimming pool every 10 minutes.
"As long as the volume is increasing, it increases the chances of a volcanic eruption onto Goma," the Goma Volcano Observatory (GVO) Director-General Katcho Karume said.
Sadly, the observatory is now facing seismic network maintenance issues, vandalism, theft, and lightning damage, Pease noted.
In addition, GVO -- responsible for issuing an alarm if the eruption occurs -- is now set to lose funding from the World Bank it has relied upon for the past 5 years.
Video courtesy of Bradley Ambrose
One of Africa's most notable volcanoes, Nyiragongo contained a lava lake in its deep summit crater that was active for half a century before draining catastrophically through its outer flanks in 1977.
In contrast to the low profile of its neighboring shield volcano, Nyamuragira, 3 470 m (11 384 feet) high Nyiragongo displays the steep slopes of a stratovolcano.
Benches in the steep-walled, 1.2 km (1.9 miles) wide summit crater mark levels of former lava lakes, which have been observed since the late-19th century.
Two older stratovolcanoes, Baruta and Shaheru, are partially overlapped by Nyiragongo on the north and south.
About 100 parasitic cones are located primarily along radial fissures south of Shaheru, east of the summit, and along a NE-SW zone extending as far as Lake Kivu.
Many cones are buried by voluminous lava flows that extend long distances down the flanks, which is characterized by the eruption of foiditic rocks.
The extremely fluid 1977 lava flows caused many fatalities, as did lava flows that inundated portions of the major city of Goma in January 2002.
Featured image credit: USGS