Predicting earthquakes is a very complex task as compared to that of the volcanic eruptions that take place as a consequence of these quakes. Not even the USGS can accurately predict these earthquakes as an earthquake occurs from deep within the layers of the earth and thus it is quite difficult to predict how shallow these depths are.
<u>Monitoring and predicting the behavior</u> of an active or extinct or dominant type of volcano is much easier as they can be studied based on magma and lava, for example, the swelling inside a volcano can predict that magma has accumulated near the surface.
Movement of magma and gases through the hydrothermal vents can be done through the thermal monitoring system also a volcano can bee seen on the surface and a earthquake in the seismic wave form underneath the surface is not.
