DYNAMICS OF LAKE ERUPTIONS AND POSSIBLE OCEAN ERUPTIONS

Abstract

Dissolved gas in liquid is able to power violent eruptions. Two kinds of such gas-driven eruptions are known in nature: explosive volcanic eruptions driven by dissolved H2O in magma at high temperatures and lake eruptions driven by dissolved CO2 in water at low temperatures. There are two known occurrences of lake eruptions, one in 1984 (Lake Monoun) and one in 1986 (Lake Nyos), both in Cameroon, Africa. The erupted CO2 gas asphyxiated ∼1700 people in the Lake Nyos eruption and 37 people at Lake Monoun. Here we review experimental simulations of CO2-driven water eruptions and dynamic models of such eruptions, and a bubble plume theory is applied to the dynamics of lake eruptions. Field evidence, experimental results, and theoretical models show that lake eruptions can be violent, and theoretical calculations are consistent with the high exit velocities and eruption columns inferred from observations. Furthermore, the dynamics of lake degassing experiments are consistent with theoretical models. Other kinds of gas-driven eruptions are possible and may have occurred in nature in the past. A concentrated and large release of methane gas or hydrate from marine sediment may result in an ocean eruption. Furthermore, injection of liquid CO2 into oceans might also lead to ocean eruptions if care is not taken. The various kinetic and dynamic processes involved are examined and quantified.