Earth's Interior

Seismic Waves

Energy transferred through the Earth generated by earthquakes.

Primary Waves (P waves)

Pressure waves that can travel through solid, liquid, and gas.

Shear Waves (S waves)

Waves that can only travel through solid and cannot travel through liquid or gas.

Core

The innermost layer of the Earth, consisting of a liquid outer core and a solid inner core.

Mantle

The layer of the Earth beneath the crust, believed to be rocky and less dense than the core.

Shadow Zone

An area where S waves are not detected, indicating the presence of a liquid outer core.

Density

The mass per unit volume of a substance, important in determining wave speed.

Moonquakes

Seismic activity on the Moon, which can be detected but are generally weaker than earthquakes.

Iron and Nickel Alloy

The composition of the Earth's core, which is primarily metallic.

Lava

Melted rock from the mantle that indicates the rocky nature of the mantle.