Why did the CO2 dissolved in the lake water of Lake Nyos suddenly come out of the solution?
This site goes into quite a bit of detail but here is a relevant excerpt; On August 15, 1984, a similar CO2 “eruption” occurred thirty kilometers away in Lake Monoun, killing 34 people. Investigators from the U.S. concluded that this event was from the CO2-rich bottom waters being overturned by a landslide, an earthquake, or abnormally heavy rains. American investigators were convinced that the same thing happened at Lake Nyos two years later. However, many European scientists were just as convinced that the Lake Nyos tragedy was the direct result of a gas-rich volcanic eruption. Most experts now favor the idea that the gas was released when the lower layers of the lake were somehow brought up to the surface.
