Question

Why do faults often occur along plate boundaries?

Answer 1

Faults often occur along plate boundaries due to the interaction of crustal plates, which can move apart, dive under one another, slide alongside, or collide. These interactions result in the Earth's crust cracking, creating faults and leading to earthquakes such as those along the San Andreas Fault. Plate tectonics also shape the Earth's topography.

Step-by-step explanation:

Faults often occur along plate boundaries because these are regions where Earth's crustal plates interact. The interaction at these boundaries can be of different types: plates can pull apart, one plate can dive under another, they can slide alongside each other, or they can collide. Such movements can cause the crust to crack, creating faults. Active fault zones are areas where the motion of one plate against another is ongoing and measurable, often at rates similar to the spreading occurring at rifts.

The motion along these zones is not smooth but occurs in sudden, violent slippages due to the build-up of stress in the crust, which then lead to earthquakes. This is why areas along plate boundaries, like the famous San Andreas Fault in California, are prone to seismic activity.

Furthermore, the tectonic plates do not cover the Earth's sphere smoothly; much like wrapping a ball with a flat piece of paper, there are going to be folds and tears—the geological equivalent of which are faults. These faults, consequential to the internal heat and motion of the plates, play a critical role in shaping the Earth's topography, including mountains.

Answer 2

Earthquakes can also occur far from the edges of plates, along faults. Faults are cracks in the earth where sections of a plate (or two plates) are moving in different directions. Faults are caused by all that bumping and sliding the plates do. They are more common near the edges of the plates.