Download Inside Earth Ch. 2 Sec. 1 Notes

Ch. 2 Sec. 1 Notes
Forces in Earth’s Crust
*The movement of Earth's plates causes stress on the rocks
Stress: A force that acts on rocks to change its shape or volume
-Stress adds energy to rock
-Energy is stored until rock changes shape or breaks
3 Types of Stress
1. Tension
-Pulls on the crust stretching it so it is thinner in the middle
-Occurs where plates move apart
2. Compression
-Squeezes rock until it folds or breaks
-Occurs where plates come together
3. Shearing
-Pushes a mass of rock in 2 opposite directions
-Occurs where plates slide past each other
*When enough stress builds up in the rocks, the rocks break and create
a fault
-Most faults occur along plate boundaries
3 Types of Faults
1. Normal Fault
-Caused by tension in the crust (move apart)
-1 rock lies above the fault (hanging wall) and the other below the
fault (footwall)
2. Reverse Fault
-Caused by compression (come together)
3. Strike-Slip Fault
-Caused by shearing (move past each other)
Changes in Earth’s Landforms
*The forces of plate movement can fold, stretch, and uplift the crust
creating visible landforms*
1. Anticline: a fold in rock that bends upward into an arch
2. Syncline: a fold in rock that bends downward into a valley
3. Folded mountains: mountains created by anticlines and synclines
4. Fault-block mountains: mountains created when 2 normal faults cut
through a block of rock
5. Plateaus: a large area of flat land elevated high above sea level