Faults and Stress

Unit 2 Lesson 2

Faults Fractures in the earth occur when a force is

applied to the underlying rock, which movement occurs.

Stress is the force per unit area acting upon a material.

There are 3 types of stress that acts upon the Earth’s rocks: Compression: decreases material volume Tension: pulls the material apart Shear: Causes the material to slip or twist

Types of Faults Slip Faults

Horizontal tension Sideways movement

Normal Fault Tension (Apart)

Down on advancing block

Thrust/Reverse Fault Compression

Uplift of advancing block

Examples of Faults Reverse Fault

Note the compression Note the uplift

San Andreas Fault Pulled apart Sideways movement