Nyiragongo, one of the world's most dangerous volcanoes
Nyragongo (dangerosity 5,9):
Nyragongo is a volcano located in the Virunga National Park, in the North Kivu region, 15 km to the North of Goma, a 1,1 million inhabitants city built on old lava flows mostly from Nyiragongo.
Nyiragongo has a lava lake in its summit crater, so the main direct threat from Nyiragongo is lava flows caused by lava lake draining through the outer flanks (like it occured in 1977 and 2002). In January 2002, Nyiragongo erupted, sending a stream of lava 200 metres to one kilometre wide and up to two metres deep through the center of the city of Goma. The lava destroyed 40% of the city (more than 4,500 houses and buildings). Luckily, agencies monitoring the volcano were able to give a warning and most of the population of Goma evacuated to Gisenyi. However, Nyiragongo's lava is foidic, a very fluid type of basaltic lava. In 1977, several fatalities were reported as the lava was very runny and fast-flowing. Imagine a fluid, fast-flowing, wide and large lava flow erupting from a flank vent (lava lake draining like in 1977 and 2002), reaching the center of Goma with no warning. It is sadly possible.
Even worse, roughly 2 million people (including Goma) live by the shores of lake Kivu. Lake Kivu has, due to volcanic activity in the region, dissolved methane and carbon dioxyde in its waters. As the lake is meromictic, any change in temperature or any landslide or earthquake (creating a wave) might provok sudden degassing of the lake: a limnic eruption.
Nyiragongo has a VAI of 1,94, this is quite high, it depicts the high frequency of its eruptions.
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