Volcanically-caused long period earthquakes are produced by vibrations generated by the movement of magma or other fluids within the volcano. Pressure within the system increases and the surrounding rock fails, creating small earthquakes.

Why do volcanic eruptions cause earthquakes?

Volcanic eruptions occur when either plates sink below another plate (subduction), heating and creating magma, or plates pull apart, allowing magma to rise to the surface. ... Thus, volcanic eruptions can cause earthquakes because of the massive amount of energy that is released during an eruption.

How are volcanoes related to earthquakes?

Most earthquakes directly beneath a volcano are caused by the movement of magma. The magma exerts pressure on the rocks until it cracks the rock. Then the magma squirts into the crack and starts building pressure again. Every time the rock cracks it makes a small earthquake.