What term describes a fracture or zone of fractures between two blocks of rock, where movement has occurred, often associated with earthquakes?

• A. Fault
• B. Ocean Basin
• C. Geocentric model
• D. Rift Valley

Answer: (A)

A fault is a fracture or zone of fractures in the crust where movement has occurred, and it’s the feature most closely tied to earthquakes. When tectonic stresses build up and rock on opposite sides of a fracture slips relative to each other, energy is released as seismic waves, producing an earthquake. If there’s displacement along the break, you have a fault; if there’s no movement, it’s just a fracture or crack.

Different fault types describe how the movement happens: vertical slip (normal or reverse faults) or horizontal slip (strike-slip faults), depending on the stress regime. The other terms refer to different things—an ocean basin is a large marine depression, a geocentric model is an older cosmology concept, and a Rift Valley is a specific landscape feature formed by extension and faulting but not the general term for a moving fracture.