Shield volcano are cave-like volcanic straights formed by the hardening of overlaying lava. These structures help further the propagation of lava, as the walls of the tube insulates the lava within. Lava tubes can account for a large portion of shield volcano activity; for example, an estimated 58% of the lava forming Kīlauea comes from lava tubes. In some shield volcano eruptions, basaltic lava pours out of a long fissure instead of a central vent, and shrouds the countryside with a long band of volcanic material in the form of a broad plateau. Plateaus of this type exist in Iceland, Washington, Oregon,
Volcano tectonic earthquake Volcano tectonic earthquake A volcano tectonic earthquake is an earthquake induced by the movement (injection or withdrawal) of magma. The movement results in pressure changes in the rock around where the magma has experienced stress. At some point, the rock may break or move. The earthquakes may also be related to dike intrusion and may occur as earthquake swarms. An example is the 2007–2008 Nazko earthquake swarm in central British Columbia, Canada. Other types of seismic activity related to volcanoes and their eruptions are long period seismic waves, which are from sudden sporadic movement of magma, which is blocked from