Lecture 11 - Earth Sciences 1081B Resources Environment and Sustainability in a Material Society Sa n A nd reas Faul t Displacement 1 E released as

1 S an A n d re a s F a ult Displacement Earth Sciences 1081B: Resources, Environment and Sustainability in a Material Society

2 “E” released as crustal plates slip past one another

Elastic rebound  deformed by tectonic forces  bend and store elastic energy - strain  Frictional resistance holds the rocks together 3 Earthquakes A. Original Position B. Build up of Strain Earthquakes where and why?

4 D. Strain Released What is an Earthquake ?

5 • direction of applied stress • the sense of motion relative to the fault Types of faults and movement based on:

“E” moves in waves Interior :  P-waves “Primary”  S-waves “Secondary Exterior:  Surface waves 6 Energy radiates in all directions from the source Focus earthquake waves originate Epicentre location on the surface directly above the focus

Body waves: travel through Earth’s interior  Primary (P) waves: 7

Body waves: travel through Earth’s interior  Secondary (S) waves 8

9 Surface; R- waves

Seismology  The study of earthquake waves ,  Seismometers are instruments that record seismic waves 10 Records the movement of Earth in relation to a stationary mass on a rotating drum or magnetic tape