The following definitions are adapted from The Earth by Press and Siever. This type of faulting occurs in response to extension and is often observed in the Western United States Basin and Range Province and along oceanic ridge systems. This type of faulting is common in areas of compression, such as regions where one plate is being subducted under another as in Japan. When the dip angle is shallow, a reverse fault is often described as a thrust fault. The San Andreas Fault is an example of a right lateral fault.
Surface rupture occurs when movement on a fault deep within the earth breaks through to the surface.
NOT ALL earthquakes result in surface rupture. When an earthquake occurs on one of these faults, the rock on one side of the fault slips with respect to the other. The fault surface can be vertical, horizontal, or at some angle to the surface of the earth. The slip direction can also be at any angle. Some earthquakes produce spectacular fault scarps, and others are completely buried beneath the surface.