Download Stress and Faults Power Point NOTES

Stress
5.1 Interactions at Plate Boundaries
Stress and Deformation
• Earth’s lithosphere is made up of crust and
upper mantle that are broken into plates.
• Each plate travels at different speeds and in
different directions.
• Collisions between plates causes stress at
plate boundaries, resulting in deformation.
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5.1 Interactions at Plate Boundaries
Stress and Deformation (cont.)
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5.1 Interactions at Plate Boundaries
Types of Stress
• Three main types of stress:
– Tension: rocks are stretched
– Compression: rocks are squeezed
– Shear: rocks slide horizontal in
opposite directions
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5.1 Interactions at Plate Boundaries
Types of Stress (p.210)
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Faults
5.1 Interactions at Plate Boundaries
Fractures and Faults
• A fracture is a break or crack in rock.
• If rock on side of a fracture has moved
relative to the other side it is called a fault.
• Three main types of faults
• Normal faults
• Reverse faults
• Strike-slip faults
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5.1 Interactions at Plate Boundaries
Normal Faults
• Normal faults result from tension stress
and slope at an angle.
• Hanging wall down relative to footwall.
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5.1 Interactions at Plate Boundaries
Reverse Faults
• Reverse faults result from compression
stress and slope at an angle.
• Hanging wall up relative to footwall.
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5.1 Interactions at Plate Boundaries
Strike-Slip Faults
• Strike-slip faults result from shearing stress
and are often vertical.
• San Andreas Fault in California. (p.212)
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