A fault scarp is a small step-like offset of the ground surface in which one side of a fault has shifted vertically in relation to the other. The topographic expression of fault scarps results from the differential erosion of rocks of contrasting resistance and the displacement of land surface by movement along the fault. Differential movement and

erosion Erosion is the action of surface processes (such as Surface runoff, water flow or wind) that removes soil, Rock (geology), rock, or dissolved material from one location on the Earth's crust#Crust, Earth's crust and then sediment transport, tran ...

may occur either along older inactive geologic faults, or recent

active fault An active fault is a fault that is likely to become the source of another earthquake sometime in the future. Geologists commonly consider faults to be active if there has been movement observed or evidence of seismic activity during the last 10,0 ...

Characteristics

Fault scarps often involve zones of highly fractured rock and discontinuities of hard and weak consistencies of rock. Bluffs can form from upthrown blocks and can be very steep, as in the case of Pakistan's coastal cliffs. The height of the scarp formation tends to be defined in terms of the vertical displacement along the fault. Active scarp faults may reflect rapid

tectonic Tectonics ( via Latin ) are the processes that result in the structure and properties of the Earth's crust and its evolution through time. The field of ''planetary tectonics'' extends the concept to other planets and moons. These processes ...

displacement and can be caused by any type of fault including

strike-slip fault In geology, a fault is a planar fracture or discontinuity in a volume of rock across which there has been significant displacement as a result of rock-mass movements. Large faults within Earth's crust result from the action of plate tectonic ...

s. Vertical displacement of ten meters may occur in fault scarps in volcanic bedrock, but is usually the result of multiple episodic movements of 5 to 10 meters per tectonic event. Due to the dramatic uplift along the fault, which exposes its surface, the fault scarp is very prone to erosion. This is especially true if the material being uplifted consists of unconsolidated sediment. Weathering, mass wasting, and water runoff can soon wear down these bluffs, sometimes resulting in V-shaped valleys along runoff channels. Adjacent V-shaped valley formations give the remaining fault spurs a very triangular shape. This formation is known as a ''triangular facet''; however, this landform is not limited to fault scarps. Fault scarps may vary in size from a few centimeters to many meters. ''Fault-line scarps'' are typically formed due to the differential erosion of weaker rocks along a fault. Such erosion, occurring over long time periods, may shift a physical

cliff In geography and geology, a cliff or rock face is an area of Rock (geology), rock which has a general angle defined by the vertical, or nearly vertical. Cliffs are formed by the processes of weathering and erosion, with the effect of gravity. ...

far from the actual fault location, which may be buried beneath a talus,

alluvial fan An alluvial fan is an accumulation of sediments that fans outwards from a concentrated source of sediments, such as a narrow canyon emerging from an escarpment. They are characteristic of mountainous terrain in arid to Semi-arid climate, semiar ...

or filled-in valley sediments. It may therefore be difficult to distinguish between fault scarps and fault-line scarps.

Examples

* The

Teton Range The Teton Range is a mountain range of the Rocky Mountains in North America. It extends for approximately in a north–south direction through the U.S. state of Wyoming, east of the Idaho state line. It is south of Yellowstone National Park, ...

Wyoming Wyoming ( ) is a landlocked U.S. state, state in the Mountain states, Mountain West subregion of the Western United States, Western United States. It borders Montana to the north and northwest, South Dakota and Nebraska to the east, Idaho t ...

is an example of an active fault scarp. The dramatic topography of the Tetons is due to geologically recent activity on the Teton Fault. * Fault scarps in Motosu, Japan, created by the 1891 Mino–Owari earthquake. * The fault scarps bounding the East African Rift Valley. * The fault scarps bounding the Rio Grande Rift in

New Mexico New Mexico is a state in the Southwestern United States, Southwestern region of the United States. It is one of the Mountain States of the southern Rocky Mountains, sharing the Four Corners region with Utah, Colorado, and Arizona. It also ...

. * The Bree fault scarp of the Roer Valley in northeast Belgium * The underwater Malta escarpment marks the eastern end of the Malta Plateau

continental shelf A continental shelf is a portion of a continent that is submerged under an area of relatively shallow water, known as a shelf sea. Much of these shelves were exposed by drops in sea level during glacial periods. The shelf surrounding an islan ...

and runs southwards from the eastern coasts from

Sicily Sicily (Italian language, Italian and ), officially the Sicilian Region (), is an island in the central Mediterranean Sea, south of the Italian Peninsula in continental Europe and is one of the 20 regions of Italy, regions of Italy. With 4. ...

and the

Malta Malta, officially the Republic of Malta, is an island country in Southern Europe located in the Mediterranean Sea, between Sicily and North Africa. It consists of an archipelago south of Italy, east of Tunisia, and north of Libya. The two ...

towards the Medina Seamounts near the African coast.

References

{{Structural geology Tectonic landforms Structural geology Seismic faults