Intraplate volcanism: The 5 percent of known volcanoes in the world that are not closely related to plate margins are generally regarded as intraplate, or "hot spot", volcanoes.
Ring of fire: The Pacific Ring of Fire is an arc of intense seismic (earthquake) and volcanic activity stretching from New Zealand, along the eastern edge of Asia, north across the Aleutian Islands of Alaska, and south along the coast of North and South America.
Lava: Magma that flows onto Earth's surface; the rock that forms when lava cools and solidifies.
Magma: Liquid rock produced under the Earth's surface; igneous rocks are made of magma.
Viscosity: The degree to which a fluid resists flow under an applied force, measured by the tangential friction force per unit area divided by the velocity gradient under conditions of streamline flow; coefficient of viscosity.
Silica Content: Silica is silicon dioxide, a compound of silicon which is found in sand, quartz, and flint, and which is used to make glass.