Science Olympiad Dynamic Planet Practice Test

In which setting would one expect to find a reverse fault?

1. Where the upper block of the fault moves down

2. Where the upper block of the fault moves up

3. In areas of lateral motion

4. In regions of no seismic activity

The correct answer is: Where the upper block of the fault moves up

A reverse fault occurs in settings where compressional forces act on the Earth's crust, causing the upper block of the fault, known as the hanging wall, to move upward relative to the lower block, called the footwall. This upward movement of the hanging wall is a characteristic feature of reverse faults, distinguishing them from other fault types. The process that leads to reverse faults is typically associated with tectonic plate collisions, where two plates are pushed together, creating stress that results in the upward displacement of the hanging wall section. This is commonly observed in mountainous regions that experience ongoing tectonic activity, where rock layers are forced to deform and slip along fault lines. In contrast to reverse faults, settings where the upper block moves down would indicate a normal fault, lateral motion would involve strike-slip faults, and regions of no seismic activity would be typically considered stable, not conducive to active faulting. These distinctions clarify why the upward movement of the upper block is critical in identifying reverse faults.