Earths Crust in Motion Stress in the Crust

Earth’s Crust in Motion

Stress in the Crust • Earthquake is the shaking and trembling that results from the movement of rock beneath Earth’s surface.

Types of Stress 1. Shearing 2. Tension 3. Compression

Types of Stress

Faults 1. Strike-Slip Fault 2. Normal Fault 3. Reverse Fault

Strike-Slip Fault • Stress that causes Strike-Slip Faults: Shearing

Strike-Slip Fault Example • The San Andreas Fault in California.

Normal Fault • Stress that causes Normal Fault is: Tension

Normal Fault Example • The Sandia Mountains in New Mexico were created by a Normal Fault.

Reverse Fault • Stress that causes a reverse fault: Compression

Reverse Fault Example • Mt Gould in Glacier National Park

Friction Along Faults • Little Friction- quicker movement, less force to overcome friction. • More Friction- stress must build up to move one plate past another. When stress is released more powerful earthquake can result.

Mountain Building • Mountains Formed by Faulting. • Fault Block Mountains- Teton Range Wyoming (2 normal faults)

Mountains by Folding • Folds are bends in rock that form when compression shortens and thickens part of Earth’s crust

Folded Mountains • Example: Himalayas and Alps

Anticlines and Synclines

Examples of Anticlines and Synclines • Anticline-Black Hills South Dakota • Syncline-Illinois Basin

South Dakota

Plateau • Example- Colorado Plateau including Four Corners (Arizona, Utah Colorado, New Mexico)