What is a characteristic of elastic rebound theory?

• A. Fluid pressure builds in the rock.
• B. Rocks melt.
• C. Temperature rises due to friction.
• D. Rocks accumulate elastic strain before an earthquake.

Answer: (D)

Elastic rebound theory describes how rocks on a fault deform elastically under tectonic stress, storing up elastic strain energy as they are slowly pushed past one another. When the stress becomes too great, the rocks rupture and snap back toward their original shape, releasing the stored energy as seismic waves—that sudden slip is the earthquake. So the key feature is that rocks accumulate elastic strain before the earthquake.

Other possibilities don’t capture this mechanism. Fluid pressure buildup describes how fluids can influence fault slip but isn’t the main idea of elastic rebound. Melting of rocks isn’t involved in this theory. Temperature rise from friction occurs during the slip itself, not the storage of elastic energy that precedes the quake.