3 most predominate reasons are....
The buoyancy of the magma
The pressure from the exsolved gasses in the magma
The injection of a new batch of magma into an already filled magma chamber
it would maybe be volcanic acid
Lava erupts due to the buoyancy of magma, the pressure from dissolved gases, and the injection of new magma into magma chambers. As magma rises, the decrease in pressure allows gases to expand and build up pressure, leading to potential eruptions. The type of magma also influences whether the eruption will be explosive or gentle.
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