Question

what causes an earthquake?
earthquakes happen when a section of a fault that is locked builds up tension until the rocks break.
earthquakes happen when heat welds the two sides of a locked section of the fault back together.
earthquakes happen when because the plates stop moving.
earthquakes happen when a locked section of the fault relaxes and moves gradually.

Explanation:

To determine the cause of an earthquake, we analyze each option:

• The first option: Earthquakes occur due to tectonic forces. When a locked fault section accumulates tension, the rocks eventually break, releasing energy as an earthquake. This aligns with geological principles.
• The second option: Heat welding fault sides is not a recognized cause of earthquakes. Earthquakes are related to stress release, not welding.
• The third option: Earthquakes are caused by plate movement, not their cessation. Plates are in constant motion, and stress from this motion leads to quakes.
• The fourth option: Earthquakes involve sudden movement, not gradual relaxation of a locked fault. Sudden slip occurs when tension overcomes friction.

Answer:

The correct option is: Earthquakes happen when a section of a fault that is locked builds up tension until the rocks break.