Science Olympiad Dynamic Planet Practice Test

What triggers earthquakes to occur?

1. Volcanic eruptions

2. Movement of tectonic plates

3. Accumulated strain release from faults

4. Changes in atmospheric pressure

The correct answer is: Accumulated strain release from faults

The occurrence of earthquakes is primarily triggered by the release of accumulated strain along faults in the Earth's crust. Tectonic plates are constantly in motion, albeit very slowly, and as they interact with one another, stress builds up in the rocks near plate boundaries. When this stress exceeds the strength of the rocks, it is released suddenly, resulting in an earthquake. This process is related to the concept of elastic rebound, where the rocks bend and deform until they can no longer hold the strain, leading to a break and the generation of seismic waves. While volcanic eruptions can also cause earthquakes, they are typically classified under a different mechanism associated with volcanic activity rather than the tectonic processes that primarily govern most seismic activity. The movement of tectonic plates is a crucial aspect of the context in which earthquakes occur, but the immediate trigger is the release of strain along faults. Changes in atmospheric pressure do not significantly affect seismic activity as their influence is not related to the geological processes that cause earthquakes.