Mount Nyiragongo is located in the Democratic Republic of Congo. The stratovolcano is part of the chain of eight volcanoes in the Great Rift Valley, which is known as the Virunga volcano chain.
Atypical of stratovolcanoes such as Mount Nyiragongo is its activity. Its eruption style of choice is Hawaiian eruptions and the generation of lava lakes and lava flows of particularly low viscosity basaltic lava.
On the surface of the lake solidified basalt plates form. These plates float on the lake surface and are punctuated by cracks of red-hot lava. The basalt plates isolate the lava lake so that molten lava remains liquefied below the surface for a long time. The feed rate of fresh material is as with most lava lakes relatively low, however the heat flow from the Earth's interior is higher than in most other volcanoes.
There had already been a lava lake here between 1923 and 1977. In January 1977 a flank eruption occurred and the lava lake flowed through a large fissure vent. It created massive lava flows with initial speeds of 100 kilometers per hour killing more than 2000 people.
In January 2002, Mount Nyiragongo erupted once again, sending a stream of lava down the slopes, destroying several villages and cutting a swath through the city of Goma before it flowing into Lake Kivu. 147 people were killed and 170,000 people were left permanently homeless after this volcanic disaster. Since June 2002, a new lava lake boils in the crater of Mount Nyiragongo.
The new lava lake in the Crater of NyiragongoThe summit of the 3469-meter-high Nyiragongo is dominated by a crater with a diameter of 1.2 kilometers, in which a lava lake has been bubbling since 2005. The lava lake was initially roughly 800 m below the crater rim and rose continuously to 450 m below the crater rim by January 2011. Several terraced plateaus in the crater indicate the status of earlier lava lakes.
Several times a day there are periods of increased activity in the lava lake associated with the formation of lava fountains. First the lava lake level rises slowly by about 10 m, before it sinks again relatively quickly. Lava fountains are formed, which can be up to 12 m high. The surface of the lava lake is in constant motion, which is caused on the one hand by convection. A second mechanism seems to be connected with the variation of the lava lake level: As the lava lake falls, the fountains and crustal plates migrate to the eastern side of the crater rim, where there seems to be a discharge into the magma chamber. A vent through which the lava rises seems to be hidden in the northwestern third of the lava lake. Time-lapse images show that from there the crustal plates on the lava lake spread radially from one point.
Tourism at NyiragongoThe Nyiragongo rises in the border area between Congo, Rwanda and Uganda. Since tribal wars have been raging in this region for years and rebels have made the Virunga volcanoes unsafe, access to the Nyiragongo is only possible under difficult conditions and associated with corresponding risks. Sad chapters of this region are the genocide of the Tutsis (in 1994 with about 1.000.000 victims mainly on the side of the Rwandan minority group of the Tutsis) and the slaughtering of the mountain gorillas, whose hands are very popular among the Chinese as a potency agent (never heard of Viagra?). According to local mythology, the souls of sinners burn in the fire of Nyiragongo, while the souls of "honest people" can enjoy eternal life on the often snow-covered summit of Karisimbi. This explains the high level of the lava lake.
During our expedition in January 2011 bureaucracy and corruption caused us problems. For example, our group was blackmailed by policemen, because they allegedly needed a permit from the tourism authority to photograph in Goma.
In quiet times the ascent to the lava lake is well organized. There is a special office of the National Park Service where you can get the necessary permission. The ascent is practically only possible accompanied by an armed ranger. In recent years, small huts have been built on the narrow crater terrace. It is not advisable to go it alone, it is best to organise the ascent with a safari operator who is familiar with the area.