Science Olympiad Dynamic Planet Practice Test

What happens to the Earth's elastic potential energy during an earthquake?

1. It increases significantly

2. It remains unchanged

3. It decreases significantly

4. It becomes kinetic energy

The correct answer is: It decreases significantly

During an earthquake, the Earth's elastic potential energy stored in rocks along fault lines is released as the rocks break and move. Initially, stress builds up in the rocks due to tectonic forces, causing elastic deformation. This stored energy increases as the strain accumulates. When the stress exceeds the strength of the rocks, they suddenly fracture, resulting in a rapid release of the stored elastic potential energy, which transforms into kinetic energy. The correct answer denotes a decrease in elastic potential energy as it is converted during the earthquake process. As the rocks release their accumulated stresses and move, the elastic potential energy diminishes significantly, transitioning into other forms of energy, notably kinetic energy, which is manifested as seismic waves that propagate through the Earth. This transformation is crucial to understanding how earthquakes release energy and cause shaking.