Stress and Energy WavesStress and Energy Waves

Movement during an EarthquakeMovement during an Earthquake

October 17, 1989 at 5:04 p.m October 17, 1989 at 5:04 p.m

StressStress

• Stress: Energy stored in the Earth’s crust

• Stress can build up at plate boundaries.

• Potential Energy

FoldingFolding

• Too much stress can cause the rocks to bend or Fold.

• This can form Mountains.

• The Appalachian mountains are folded mountains.

The Appalachian Mountains The Appalachian Mountains (Tennessee) (Tennessee)

FaultingFaulting

• When there is too much stress, the rocks in the crust may break.

• This can cause earthquakes.

Fault LinesFault Lines

Seismic WavesSeismic Waves

• Waves of energy that move through the Earth during an Earthquake.

• There are three types:– Primary waves– Secondary waves– Love-Rayleigh waves

Primary (P) wavesPrimary (P) waves

• Body waves move through the interior of the Earth.

• They are the fastest seismic wave, therefore will always arrive first.

• Move through solid, liquid and gas.

• They are compression waves, they move particles forward and backward.

S wavesS waves

• Also body waves. • Travel more slowly and

arrive second. • Can only move through

solids. • Also called shear waves,

because they move particles side to side.

• AKA transverse waves.

Love-Rayleigh WavesLove-Rayleigh Waves

• Surface waves.• Solid rock only.• Move in a rolling

motion.• Cause ripples on the

surface.

Seismology and Seismic WavesSeismology and Seismic Waves