Earthquakes

Earthquake Vibration due to the rapid release of energy Caused by slippage along a break in earth’s crust

Faults Fault: fracture (break) in Earth where movement has occurred Fractures form when stress on rocks exceeds their strength Three types of stress: Tension Compression shearing

Fault types Reverse: caused by compression Normal: caused by tension Strike-slip: caused by shearing

Location of the earthquake Focus: the point under the surface where the earthquake starts Epicenter: the point of the surface directly above the focus

Earthquake waves Seismic waves: the vibrations of the ground during an earthquake Primary waves Push and pull rock in the same direction the wave is moving Like a slinky Fastest wave wave simulation

Cause rock to move at right angles to the direction of wave movement Secondary waves Cause rock to move at right angles to the direction of wave movement Surface waves Travel along earth’s outer surface Move in two directions as they pass through rock Wave animation

Measuring earthquakes Richter scale: measures wave amplitude; based on size of largest wave Moment magnitude: measure using average displacement along the fault, surface area of the fault, and strength of the rock involved intensity; greatest near the epicenter

Earthquake hazards and research Earthquake destruction Anatomy of an earthquake (Learn360) Swaying Top ten tsunami

Liquefaction When fluid saturated soil liquifies due to seismic vibrations Bobbing Building Liquefaction video More liquefaction - shifting sidewalk

Landslide Christchurch earthquake

Tsunamis and fires Tsunami Formation of a tsunami Tidal Bore Tidal bore Amazon

Pancaking