Science Olympiad Dynamic Planet Practice Test

What does a thrust fault specifically refer to?

1. A strike-slip fault with lateral motion

2. A reverse fault with a dip of 45 degrees or less

3. A normal fault located at the ocean floor

4. A fault that causes significant earthquake risks

The correct answer is: A reverse fault with a dip of 45 degrees or less

A thrust fault specifically refers to a type of reverse fault characterized by a shallow angle of dip, typically less than 30 degrees, although the maximum dip can sometimes extend up to 45 degrees. In a thrust fault, the hanging wall moves up relative to the footwall under compressional stress. This type of fault often occurs in convergent plate boundaries where two tectonic plates collide, causing one plate to be forced over the other. The significance of the angle in a thrust fault is important because it allows the fault to accommodate large horizontal displacements over extensive areas, which can lead to the formation of significant geological features such as mountain ranges. The distinction between thrust faults and other types of faults, such as normal or strike-slip faults, hinges on this shallow dip and the movement dynamics involved.