Fault block

A fault block is a huge piece of rock. It can stretch for hundreds of kilometers. Fault blocks form because of forces inside the Earth's crust.

These blocks are created when large areas of bedrock split apart. This splitting happens because of faults. Faults are fractures in the Earth's surface. The rocks in these blocks usually have a similar type or structure. This is called lithology.

The movement of fault blocks is mostly side to side. This movement happens parallel to the Earth's surface. It is linked to the shifting of tectonic plates. Sometimes blocks move up or down. This can create landforms like mountains, hills, ridges, lakes, and valleys. When one block moves up and the next block drops down, it forms high cliffs. These cliffs are called escarpments. The movement of these blocks can also tilt the land. This happens as the crust compacts or stretches at certain points.

Fault-block mountains

See also: List of mountain types and Mountain building

Fault-block mountains form when the Earth's crust stretches apart. This process is called rifting. The stretching creates long valleys and tall mountains. Examples include the East African Rift and Death Valley in California.

There are two main kinds of these mountains. One type has uplifted blocks of land between two cracks, or faults, in the Earth's surface. The other type has tilted blocks, where one side of a fault tilts upward more than the other. These tilted mountains are common in the western United States.