EarthquakesEarthquakes

What is an earthquake?What is an earthquake?

The shaking and trembling that results from the sudden movement of part of the Earth’s crust.

FaultFault

A break or crack in Earth’s crust along which movement has occurred.

Focus / EpicenterFocus / Epicenter

Focus: The point beneath the earth’s surface where the rocks break and move.

Epicenter: The point on the earth’s surface directly above the focus

Seismic WavesSeismic Waves

P-Waves (Primary Waves): These compression waves travel the fastest and can pass through solids, liquids and gases.

P-wave movie

S-WavesS-Waves

(Secondary Waves) These waves travel slower than P-waves and can travel through solids, but not liquids.

S-wave movie

L-Waves (Surface Waves)L-Waves (Surface Waves)

The slowest and most damaging wave that moves through the earth like an ocean wave.

L-Wave Movie

SeismographSeismograph

This is an instrument detects and measures earthquakes.

TsunamisTsunamisAlso known as Tidal waves, these are ocean

waves created by earthquakes.