Fault (Geology)

earthquakes · plate tectonics · earth science · rock movement

Cracks in the ground. A fault is a break in Earth's rocky crust where two massive pieces of rock have shifted and moved apart. These aren't tiny cracks you'd find in a sidewalk, but enormous fractures that can stretch for miles underground.

Earthquakes happen here. When rock pieces along a fault suddenly slip and move, all that energy gets released as shaking and rumbling. This rapid movement is what causes most of the earthquakes we feel on Earth's surface.

Plate boundaries. The biggest faults in the world form where Earth's tectonic plates meet and collide. These plate boundary faults can be thousands of miles long and reshape the landscape over millions of years.

Slow-motion movement. Not all faults move dramatically, though. Some faults creep very slowly over time without causing earthquakes, shifting rock gradually like a turtle moving across a road.

Mountains and valleys. As faults shift rock over thousands of years, they can push up mountains or drop down valleys. The surface of Earth is constantly being reshaped by fault movement.