Which of the following faults involves the horizontal sliding of two parallel surfaces?

• A. Thrust fault
• B. Normal fault
• C. Strike-slip fault
• D. Reversed fault

Answer: (C)

The strike-slip fault involves the horizontal sliding of two parallel surfaces, which is characterized by the lateral movement of rock masses along the fault line. This type of faulting occurs primarily due to shear stress, where the forces acting on the crust push segments of the earth sideways against each other.

In contrast, thrust faults, normal faults, and reversed faults primarily involve vertical displacements of rock layers rather than horizontal sliding. Thrust faults, for instance, result from compressional forces that push one block of crust over another, typically at a steep angle. Normal faults occur due to extensional forces that pull the crust apart, resulting in one block dropping down relative to another. Reversed faults, which are similar to thrust faults, are characterized by the upward movement of one block over another but also do not involve horizontal motion like the strike-slip faults do.

Understanding these distinctions highlights why the strike-slip fault is the correct response, focusing on the nature of movement along the fault surfaces.