Crust Earth's outer layer; includes the rock of the ocean floor and large areas of land

The thickest layer of Earth; found just below the crust Mantle The thickest layer of Earth; found just below the crust                                        

Core The dense center of Earth; a ball made mostly of two metals, iron and nickel                                        

Continent-sized slab of Earth's crust and upper mantle Plates Continent-sized slab of Earth's crust and upper mantle

A vibration, or shaking, of Earth's crust earthquake A vibration, or shaking, of Earth's crust

A break in Earth's crust along which rocks move . fault A break in Earth's crust along which rocks move .

focus The point underground where the movement of an earthquake first took place

epicenter The point on the surface of Earth that is right above the focus of an earthquake.

An instrument that records earthquake waves . seismograph An instrument that records earthquake waves .

volcano A mountain that forms when red-hot melted rock flows through a crack onto Earth's surface.

Melted rock inside Earth. magma Melted rock inside Earth.

A melted rock that reaches Earth's surface lava A melted rock that reaches Earth's surface

vent The rocky tube in a volcano through which magma rises toward the surface.

An underground pool below a volcano that holds magma magma chamber An underground pool below a volcano that holds magma

crater A large basin formed at the top of a volcano when it falls in on itself.