Question

Fault in which the upper block above the fault plane moves up and over the lower block

Option a: Reverse fault
Option b: Strike-slip fault
Option c: Normal fault
Option d: Thrust fault

Answer 1

The type of fault where the upper block moves up and over the lower block is either a reverse fault or, when the angle of dip is less than 30 degrees, a thrust fault.

Step-by-step explanation:

The type of fault in which the upper block above the fault plane moves up and over the lower block is known as a reverse fault or a thrust fault. Reverse faults are formed during the compression and shortening of the Earth's crust, which typically occurs at convergent plate boundaries. These faults have a steep angle of dip, and the block above the fault (the hanging wall) moves upwards relative to the block below (the footwall). When the angle of dip is shallow, usually less than 30°, the fault is specifically termed a thrust fault. Thrust faults can create distinctive geological features, such as klippes and windows, and are often associated with mountain building processes like those seen in the Appalachians.