Why scientists are warning of limnic eruption in Nyiragongo

Experts and authorities are now warning people living near Mount Nyiragongo in Eastern Congo to remain vigilant and listen to news bulletins, as the situation “may change quickly”.

They warn of a potentially catastrophic scenario – a “limnic eruption” that could smother the area with suffocating carbon dioxide.

They say due to the volcano’s proximity to Congo’s Lake Kivu, it could cause a limnic eruption, in which carbon dioxide dissolved in the water is released, suffocating people.

Liminic eruption occurs when a body of water is sufficiently disturbed due to volcanic activities forcing it to release large volumes of the gas it contains.

This comes after risks assessment at the Nyiragongo volcano’s summit, revealed the presence of magna under the Goma area, with an extension under Lake Kivu because of the seismicity and ground deformation.

On Friday, a cloud of black smoke was seen rising from the crater on the horizon, leading to the conclusion that the volcano is still active.

Several days of aftershocks, some of them equivalent to minor earthquakes, and tremors have been reported since Saturday.

According to Dr Robin George Andrews, Lake Kivu has a lot of carbon dioxide trapped with it—about 70 cubic miles’ worth and holds 15 cubic miles of noxious methane.

He warns that should a major volcanic eruption occurs in the lake basin, both gases will pour into the shoreline suffocating anyone caught in it.

“If a major volcanic eruption takes place in the lake’s basin, both gases could pour onto the urbanised shoreline, asphyxiating anyone caught in it,” he said.

A limnic eruption is a very rare natural event, disastrous effects have been recorded only two times, both times in Cameroon, 1984 at Lake Monoun, causing the death of 37 persons, and 1986 at Lake Nyos, killing over 1700 people.

Fastest lava

Dr Andrew, a science journalist with a PhD in Volcanology says Nyiragongo’s lavas is one of the fastest in the world surging at 64 kilometres per hour and could be difficult to outrun during eruptions.

This, he attributed to the fact that the lava in the area lacks silica, a compound that gives most lavas some structural rigidity that stops them from flowing too quickly.

“With eruptions sometimes giving no clear warnings, the lava flows can ambush locals and will be dangerous,” he adds.

He added that under the right conditions, magma mixing with shallow bodies of water can trigger explosive blasts, a style of volcanic activity called phreatomagmatism.

He says recent work has shown that in the past 12,000 years or so there have been at least 15 phreatomagmatic eruptions in the Goma area.

Such eruptions, which can begin with little warning, can cause a lot of damage through land-excavating explosions and scorching, super-fast clouds of volcanic gas and ash.

The strato-volcano spewed rivers of lava that claimed nearly three dozen lives and destroyed the homes of some 20,000 people before the eruption stopped.

But for the last two days, scientists monitoring the volcano have since recorded hundreds of aftershocks.

Tens of thousands of people had fled Goma after Nyiragongo erupted on Saturday night but many then returned when the eruption ended the following day.

The eruption ploughed through 17 villages, destroyed hundreds of homes, killed dozens, separated hundreds of children from their families, and cut off water pipelines and power supplies.

In 2002 Its last major eruption, in 2002, left hundreds of people dead and more than 120,000 homeless

In 1977, Mount Nyiragongo produced the deadliest eruption in Africa after it erupted killing over 2,000 people