ACTIVE: Violent, by action.

ASH: Powdery residue left after burning.

CORE: Inner central region of the earth.

CRUST:  Outer layer of the earth.

DORMANT: In active or temporarily so; alive but not growing.

EARTHQUAKE: Convulsion of the earth’s surface.

ERUPT: Break out suddenly dramatically.

EXTINCT: That no longer erupts.

MAGMA: Molten rock under the earth’s crust, which forms igneous rock.

MANTLE: Inner layer of the earth under the crust.

MOLTEN: Melted, made liquid heat.

STEAM: Vapor from heated water.

VOLCANO: Mountain from which lava steam, etc., escape through openings in the earth’s crust.

VOLCANOLOGIST: One who studies science concerned with volcanic phenomena.