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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)