Science Olympiad Dynamic Planet Practice Test

What does the elastic rebound theory describe?

1. The rapid movement of tectonic plates

2. The gradual build-up of strain followed by sudden earthquake failure

3. How earthquakes can trigger volcanic activity

4. The energy transformation during a seismic event

The correct answer is: The gradual build-up of strain followed by sudden earthquake failure

The elastic rebound theory provides a fundamental explanation for how earthquakes occur. It posits that when stress builds up in the Earth's crust due to tectonic forces, it causes deformation, or strain, in the rocks along fault lines. Over time, this strain accumulates until the stress exceeds the strength of the rocks, leading to a sudden release of energy in the form of an earthquake. This release causes the deformed rocks to "snap back" to their original, undeformed shape, hence the term "elastic rebound." The essence of this theory is captured in the description of a gradual build-up of strain followed by a sudden earthquake failure. This highlights the process of energy accumulation and the eventual breaking point that causes an earthquake, making it the correct answer. Understanding this theory is crucial for comprehending seismic activity and earthquake mechanics, as it emphasizes the cyclical nature of stress and strain in the geological processes of the Earth.