Science Olympiad Dynamic Planet Practice Test

What primarily generates earthquakes at transform boundaries?

1. Magma movement

2. Displacement of rock along a fault

3. Volcanic eruptions

4. Shifts in ocean currents

The correct answer is: Displacement of rock along a fault

Earthquakes at transform boundaries primarily occur due to the displacement of rock along a fault. At these boundaries, two tectonic plates slide past each other horizontally. This lateral movement generates stress along the fault lines where the plates interact. As the stress builds up over time due to friction and the rigidity of the rocks, it eventually exceeds the strength of the rocks, causing them to break and slip. The sudden release of energy during this slipping manifests as an earthquake. This movement does not involve the vertical movement of plates like at convergent or divergent boundaries, nor is it the result of magma movement that typically occurs at volcanic boundaries. Volcanic eruptions are more associated with divergent boundaries or subduction zones, and shifts in ocean currents do not contribute to geological stress or fault displacement. Thus, the correct focus is on the displacement of rock along a fault, which is fundamental to how earthquakes are generated at transform boundaries.