ES 4.1: Forces in Earth’s Crust

Earthquakes

• How does stress change Earth’s crust?

• How do faults form?

• How does plate movement create new landforms?

Big Questions???

Tension: When two plates pull apart

Compression: When two plates come together

Shearing: When two plates slip past each other

Types of Stress (stress adds energy)

- 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

Faults (Where Earthquakes occur)

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

Types of Faults

Compression: Folded Mountains, Anticline & Syncline

Tension: Rift Valleys & Basins

Landforms Created by Stress