Faults where the rock layers on one side of the fault plane have moved differently than the layers on the other side are called unsymmetrical faults. The three main types of unsymmetrical faults are normal faults, reverse faults, and thrust faults. Normal faults occur when the rock layer above the fault plane drops down relative to the layer below, reverse faults happen when the layer above moves upward relative to the layer below, and thrust faults are similar to reverse faults but involve much larger displacements of rock.

1. Chapter 12
Unsymmetrical Faults