Question

In thrust faulting, ____________.

a. grabens develop on the footwall block
b. the crust is shortened and thickened
c. horizontal, tensional stresses drive the deformation
d. the hanging wall block slips downward along the thrust fault

Answer 1

In thrust faulting, the crust is shortened and thickened due to the upward movement of the hanging wall block over the footwall block.

Step-by-step explanation:

In thrust faulting, the dominant process is that the crust is shortened and thickened. This occurs when compressional stresses drive a block of rock upwards along the fault plane, over the top of another block. The description matches option b, indicating that thrust fault movement results in the crust being shortened and thickened. In contrast to other faulting processes, graben formations are typically associated with normal faults rather than thrust faults, and thrust faulting entails compressional, not tensional, stresses. Therefore, option d, suggesting the hanging wall block slips downward, is characteristic of normal faults rather than thrust faults, which involve upliftment of the hanging wall block.