Magmatic Gases and High-temperature Volcanic Gases
Gases are released from magma through volatile constituents reaching such high concentrations in the base magma that they evaporate. (Technically, this would be described as the exsolution and accumulation of the gases upon reaching excess supersaturation of these constituents in the host solution (magmatic melt), and their subsequent loss from the host by diffusion and phase separation into bubbles). Molten rock (either magma or lava) near the atmosphere releases high-temperature volcanic gas (>400 °C). In explosive volcanic eruptions, sudden release of gases from magma may cause rapid movements of the molten rock. When the magma encounters water, seawater, lake water or groundwater, it can be rapidly fragmented. The rapid expansion of gases is the driving mechanism of most explosive volcanic eruptions. However, a significant portion of volcanic gas release occurs during quasi-continuous quiescent phases of active volcanism.
Read more about this topic: Volcanic Gas
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