Viscosity		rapidly moving volcanic material
pluton		forms when material ejected high into the air falls back to earth and piles up around the vent.
batholith		larger depressions.
stock		intrusive igneous rock bodies.
laccolith		rock fragments thrown into the air during a volcanic eruption.
sill		is a mountain with broad gently sloping sides and a nearly circular base.
dike		irregularly shaped masses of coarse-grained igneous rocks cover at least 100 km and take millions of years to form.
vent		at the top of a volcano, around the vent, is a bowl shaped depression
crater		a mushroom-shaped pluton with a round top and flat bottom
caldera		is a pluton that cuts across preexisting rocks
shield volcano		the internal resistance of flow
cinder-cone volcano		forms when layers of volcanic fragments alternate with lava.
composite volcano		an opening in the crust where lava erupts.
tephra		is a pluton that forms when magma intrudes parallel to layers of rock
pyroclastic flow		hot regions of earths mantle where high temps plumes of mantle material rise toward the surface.
hot spot		irregularly shaped plutons that are similar to batholiths but are smaller in size