The movement of tectonic plates can cause volcanic eruptions

Earthquake for students

Earthquakes and volcanoes

Earthquakes are particularly common in regions of the world where there are many volcanoes. Both natural phenomena have their origin in the forces that make the continents wander. Magma can rise along cracks in the rock that form at the plate boundaries. The formation of magma is also partly related to plate tectonics. If two continental plates collide, it can happen that the heavier plate gives way downwards. This plate then dips into the earth's mantle. Due to the high temperatures in the earth's mantle, the rock of the submerged plate is melted and magma is created. This magma rises behind the plate boundary and erupts at volcanoes.

Earthquakes that occur along plate boundaries and faults in the rock are called tectonic earthquakes. But there are also earthquakes that arise directly from the rise of magma. The magma takes up space underground and breaks the surrounding rock as it ascends. Such earthquakes are called volcanotectonic earthquakes. When a volcano erupts, the ground trembles incessantly. This floor tremor is called tremor. Tremor is triggered by magma and gas and is directly attributable to their movements in the subsurface.

Volcanic explosions can create pressure waves that can also be transmitted through the rock. In this case, explosion earthquakes occur.
With the help of earthquakes in volcanoes, researchers try to predict if and when a volcano will erupt. Sometimes these predictions also work. Often times, these earthquakes occur just a few hours before a volcanic eruption. Then the warning is relatively short and people have little time to escape. In this case, the earthquakes are useful as they can warn people.




Photo: Bromo volcano. Volcanic eruptions can trigger earthquakes. It also works the other way around. © Marc Szeglat