Erosion and Deposition: Wind, Gravity, and Living Things — Quiz
Question 9 • Earth and Space Science
A coastal highway was built on a bluff overlooking the ocean in a region with frequent tectonic activity. The bluff sits above a fault line that shifts slightly, even during minor earthquakes. Recently, inspectors observed widening cracks along the road, and residents reported loud popping sounds from the slope during a storm. Which explanation best describes what is happening and what may occur next?
Answer
A
Tectonic stress is causing thermal expansion along the roadbed, creating minor surface changes only.
B
Wave action is carving out the bluff from below, but the fault line makes no contribution to slope instability.
C
Cracks are likely from salt crystal growth in coastal rock, not related to gravity-driven processes.
D
The combination of fault movement and water infiltration is increasing stress in the slope, likely leading to a sudden landslide.
Explanation
Fault movement can weaken and stress the bluff, while storm water infiltrating cracks adds weight and reduces the strength of the slope. Widening cracks and popping sounds are warning signs that the slope is deforming and may fail suddenly in a landslide. Choice D best connects the tectonic activity and water infiltration to that risk.
AI-written and checked against the verified answer.