Earthquake Notes

Earthquakes happen in the Lithosphere (outer, rigid layer of Earth).

EARTHQUAKE-The shaking and vibrating of the earth caused by large and sudden releases of energy.

Lithosphere

Earthquake WavesEnergy from the earthquake is

transferred through the Earth in seismic waves

2 types of Waves are generated in an earthquake:Primary (P) waves: are fastest wavesSecondary (S) waves: are slower than P

waves

Primary Waves (P-waves)Faster waveCompresses and relaxes material as it movesForce comes from same direction as wave

movement

Secondary Wave (S-wave)Slower waveWave moves up and down like a roller coaster

through the materialForce occurs 90 degrees (angle) from direction

of wave movement

Focus: actual location of the earthquake (where energy is released). P and S waves originate here.

Epicenter: the point on the Earth’s surface directly above the focus.

Earthquake Magnitude: a measure of the energy releaseda difference of 1.0 magnitude is

32 times greater in energy)

tsunamis: ocean waves generated from earthquakes on the ocean floor.