ASBOG Practice Exam

What characteristic defines a listric fault's curvature?

1. Greatest curvature near the surface

2. Uniform curvature throughout

3. Concave curvature

4. Flat curvature at depth

The correct answer is: Greatest curvature near the surface

A listric fault is characterized by a curvature that diminishes with depth, typically appearing with greater curvature near the surface and becoming flatter as one moves deeper into the Earth. This behavior is due to the mechanics of faulting and the way stress is distributed in the crust. Near the surface, the fault's shape is more pronounced because of the factors such as the reduction of pressure and the rigidity of the rocks, which allows the fault to curve more sharply. As depth increases, the conditions change, leading the fault to flatten out, thus exhibiting less curvature. This characteristic is significant in geological studies and seismic assessments because it affects how faults propagate during tectonic activity and how they may influence the surrounding rock structures. Recognizing the curvature pattern of listric faults is vital for understanding their potential impacts on landform evolution and natural hazards, such as earthquakes.