Evidence from a volcano’s history, earthquakes, slope deformation, and gas emissions can help predict future volcanic eruptions. Observation satellites are sometimes used to monitor changes in gas, temperature, and formations at volcanic sites.
History of Volcanic Activity
Explosive eruptions are caused by gas-rich magma that churns within the magma chamber. This churning creates pressure, which can overwhelm and break through the rock that encases it.
Effusive eruptions are caused by mafic magma buildup. Although the pressure builds enough for the magma to erupt, it does not erupt with the same force as felsic magma. The magma pushes toward the surface through fissures.