Magnitude of volcanic eruptions

1. Tectonic processes of volcanic eruptions

a) magma consisting of dissolved gases is less dense

b) forces its way upward and breaks through weak areas in the Earth’s crust

2. Magnitude of volcanic eruptions

a) determined by amount of dissolved gases and magma viscosity

b) stratovolcanoes erupt violently and shield volcanoes emit magma gently

3. Measuring volcanic eruptions

a) Volcanic Explosivity Index measures relative explosivity of historic eruptions

b) considers the volume of ejected materials, height of eruption cloud and duration of the eruption


The Volcanic Explosivity Index (VEI) is a relative measure of the explosiveness of volcanic eruptions. https://volcanoes.usgs.gov/vsc/glossary/vei.html

https://volcano.oregonstate.edu/how-big-are-eruptionshow-big-are-eruptions