Athletic field in Taiwan

Forces in Earth’s Crust

Stress: a force that acts on rock to change its shape or volume. (This may take millions of years)

3 Types of Stress:1. Tension: pulls on the crust stretching rock so that it becomes thinner in the middle

2. Compression: squeezes rock until it folds or breaks

3. Shearing: pushes a mass of rock in 2 opposite

directions

Faults: occur along plate boundaries, where the forces of plate motion push or pull the crust so much that the crust breaks

3 types of faults1. Normal fault: tension in Earth’s crust pull rocks apart;

hanging wall slides downward

footwall hanging wall

2. Reverse fault caused by compression in the crust, the hanging wall slides upward

3. Strike-slip fault rocks on either side move past each other sideways with little up –or –down motion

Normal Fault

Reverse Fault

Strike-Slip fault

Changing Earth’s surface:over millions of years, the forces of plate

movement can change a flat plain into land forms such as*anticline- upward fold in rock formed by compression*syncline- downward fold in rock formed by compression*plateau- large area of flat land elevated high above sea level

Anticline Syncline

*Folded mountains- where 2 plates collide Alps in Europe and Himalayas in Asia

*Fault-Block mountains – where 2 faults parallel to each other pull apart, each side slides down

Part of the Rockies