What is the main characteristic of a reverse fault?

The defining characteristic of a reverse fault is that the foot wall moves upward relative to the other side of the fault, known as the hanging wall. This movement occurs due to compressional stresses in the Earth's crust, which push the rock masses together. In a reverse fault, the compression forces cause the hanging wall to be thrust over the foot wall, making this type of fault particularly significant in areas experiencing tectonic convergence.

In the context of the other options, the movement described in the choices that refer to the foot wall moving down or horizontal movement does not accurately represent the mechanics of a reverse fault. Similarly, the formation of new land is not a primary feature associated with reverse faults, but rather with processes like volcanic activity or sediment deposition. Understanding the mechanics of fault movement, particularly regarding reverse faults, is crucial for comprehending geological formations and seismic activity.