Forces in Earth

1
Forces in Earths Crust
2
Stress

• A force that acts on an area of rock to change
  its shape or volume.

3
There are 3 types of stress

• Tension stretches rocks
• Compression pushes rock together
• Shearing pushes the rock in two opposite
  directions

4
Questions

• What type of landforms results from tension?
• What type of landform results from compression?

5
Faults

• When enough stress builds up in rock, the rock
  breaks, creating a fault.
• Most faults occur along plate boundaries

6
There are 3 kinds of faults

• Normal Faults - Tension in crust pulls rock
  apart.
• Reverse Faults - Compression pushes rock together
• Strike-Slip Faults Shearing causes rocks to
  slip past each other

7
Mrs. Browns Fault Movie

• http//youtu.be/hfir5KQpu6c

8

• Hanging Wall The block of rock that is above
  the fault plane
• Footwall The block of rock that is below the
  fault plane.

9

• In a normal fault, the hanging wall slips down
  relative to the footwall

10

• In a reverse fault, the hanging wall moves up
  relative to the footwall

11

• San Andreas fault is a strike-slip fault with
  little up or down motion

12

• The forces of plate movement can change a flat
  plain into anticlines, synclines, folded
  mountains, fault-block mountains, and plateau.

13
Fault Block Mountain

• When two normal faults cut through a block of
  rock, a fault block mountain forms.

14

• Q Where in California are there fault-block
  mountains?
• A The Sierra Nevada and Mojave Desert regions.

15
Plateau

• A large area of flat land elevated high above sea
  level without much folding or faulting.