1. Earth's Crust in Motion

2. Earthquakes So…. What is an Earthquake? And… What are some things that can cause them?

3. Stress in the Crust 1.An earthquake is the shaking that results from the movement of rock beneath Earth's surface. –This is a super powerful force!!! –These forces are examples of stress. 2.Stress is a force that acts on rock to change its shape or volume.

4. Types of Stress 3.There are three different kinds of stress that occur in the Earth’s crust… –Shearing –Tension –Compression All of this stress works over millions of years to change the shape of rock. 4.So…Any change in the shape of Earth's crust is called deformation.

5. Shearing 5.Stress that pushes a mass of rock in two opposite directions is called shearing. Shearing can cause two slabs of rock to slip past each other like the picture below. What feature in California is an example of this?

6. Tension 6.Tension is a stress that pulls on the crust, stretching rock so that it becomes thinner in the middle. Tension occurs where two plates are moving apart. Think of pulling a Milky Way candy bar apart. What ocean feature is this an example of?

7. Compression 7.Compression is a stress force that squeezes rock until it folds or breaks. One plate pushing against another plate can compress rock easily….