Earthquakes

1. Where the crust is being pulled apart, normal faulting occurs, in which the overlying hanging-wall block moves down with respect to the lower foot-wall block.
2. Where the crust is being compressed, reverse faulting occurs, in which the hanging-wall block moves up and over the foot-wall block – reverse slip on a gently inclined plane is referred to as thrust faulting.
3.  This ‘strike-slip’ movement is described as sinistral, when the far side moves to the left, and dextral, when the far side moves to the right.
4. An oblique slip involves various combinations of these basic movements, which include both reverse and dextral movement.

After watching these three videos, you should be able to answer the following question. Make sure to bring your answer to class as I will be collecting it. 

What is the main cause of Earthquakes?