Earthquake Vocabulary

Scale used to rate the magnitude of earthquake activity

Richter Scale

The start point of an earthquake, can be several kilometers underground

Focus

The place on the earth's surface that is directly above the focus

Epicenter

An elastic wave in the earth produced by an earthquake.

Seismic Waves

secondary earthquakes, usually after a larger quake

Aftershocks

A type of fault where the hanging wall slides downward; caused by tension in the crust

Normal Fault

a type of fault where the hanging wall slides upward; caused by compression in the crust

Reverse Fault (Thrust Fault)

a type of fault where rocks on either side move past each other sideways with little up or down motion

Strike-Slip Fault

devastating waves triggered by earthquakes

Tsunami

earthquake waves that pass through the interior of the earth.

P Waves

S Waves

Body waves

the first or "primary" waves to reach a seismic station, they travel rapidly and penetrate both solid and liquid rock

P Waves

the "secondary" waves to reach seismic stations, stronger and slower than primary waves

S Waves