Earthquakes

Fault Crack or fracture in Earth’s crust along which movement occurs Occur at plate boundaries Plate boundaries may have more than one fault

Earthquakes Vibrations caused by the rupture and sudden movement in Earth’s crust

Scientists that study earthquakes Seismologists Scientists that study earthquakes

Earthquakes Focus Location where rocks move along a fault and seismic waves originate Epicenter Location on Earth’s surface directly above the earthquake’s focus

Earthquakes Seismic Waves Energy that travels as vibrations on and in Earth

Earthquakes Types of Seismic Waves Primary (P) Waves Longitudinal or compression waves Fastest waves of the earthquake, arrive first at distant points Move back and forth in the same direction the wave is traveling

Earthquakes Types of Seismic Waves Secondary (S) Waves Transverse waves Moves perpendicular to the direction the wave is moving Travels through solid rock

Earthquakes Types of Seismic Waves Surface Waves Cause particles in the ground to move up and down in a rolling motion Travel only on Earth’s surface

Earthquakes Magnitude How much energy is released during an earthquake Measured on the Richter scale 1 to 9.9