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and volcanoes is very evident where tectonic plates meet. The movement of magma within a volcano can also trigger earthquakes. As magma rises through the Earth’s crust, it fractures surrounding rocks and generates seismic activity. These earthquakes are known as volcano-tectonic earthquakes and are typically of lower magnitude. Volcanic eruptions can generate earthquakes because the upward movement of magma can cause the overlying rocks to crack and shift, leading to volcanic earthquakes. These earthquakes are often accompanied by the release of ash and pyroclastic flows from the volcano. A pyroclastic flow is a fast moving current of volcanic matter and hot gas that flows away from a volcano at average speeds of 62 mph (100 kph) but can be as fast as 435 mph (700 kph). However, not all earthquakes lead to volcanic activity, and volcanic eruptions are not always caused by seismic activity.

Earthquake energy forms in an Earth layer called the asthenosphere. Currents in the molten rock cause energy to build and then release at the tectonic plate boundaries.

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Facing the Weather: Earthquakes