Earthquakes ES 4.1: Forces in Earth’s Crust
Big Questions??? • How does stress change Earth’s crust? • How do faults form? • How does plate movement create new landforms?
Types of Stress (stress adds energy) • Tension: When two plates pull apart • Compression: When two plates come together • Shearing: When two plates slip past each other
Faults (Where Earthquakes occur) • - Stress built up in rock is released to form a fault. • Two sides to a Fault • Hanging Wall: the side of the fault you CAN’T walk down • “Foot”Wall: the side of the fault you CAN walk down
Types of Faults • Normal Fault: Where the hanging wall slips downward and footwall slips upward • Reverse Fault: Where the hanging wall slips upward and the footwall slips downward • Strike-Slip Fault: Where there is no hanging wall or footwall. The two sides slip past each other
Landforms Created by Stress • Compression: Folded Mountains, Anticline & Syncline • Tension: Rift Valleys & Basins