Scarp (landform)

small step or offset on the ground surface where one side of a fault has moved vertically with respect to the other
(Redirected from Escarpment)

Scarp is a term in geology and geography with several similar meanings.

  • A scarp is a cliff or steep slope.[1][2] The word is derived from the Italian scarpa, meaning 'shoe'.[3]
    • The surface of the steep slope is called a scarp face.
  • A fault scarp is a steep cliff made by movement along one side of a fault.
  • An escarpment is a steep slope or long cliff that occurs from faulting and resulting erosion. It separates two relatively level areas of different height.
    • A cuesta is an asymmetric ridge with an escarpment on one side and a gentle dip slope on the other side.
A fault scarp created by the 1983 Borah Peak earthquake
Escarpment face broken by a fault, Cumberland Plateau, Tennessee

Formation

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Scarps are generally formed by one or both:

  1. differential erosion of sedimentary rocks, or by
  2. vertical movement of the Earth's crust along a geologic fault.

Most commonly, an escarpment is a transition from one series of sedimentary rocks to another series of a different age and composition.

Escarpments are also frequently formed by faults. When a fault displaces the ground surface so that one side is higher than the other, a fault scarp is created. This brings a piece of high ground next to an area of lower ground.

More loosely, the term scarp describes the zone between coastal lowlands and continental plateaus. A marked, abrupt change in height is caused by coastal erosion at the base of the plateau.

 
Schematic cross section of a cuesta, dip slopes facing left, and harder rocklayers in darker colors than softer ones.

References

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  1. Easterbrook, D. J. 1999. Surface processes and landforms. 2nd ed, Prentice Hall, New Jersey.
  2. Summary: Escarpments, US Army Corps of Engineers.
  3. scarp - Definition from the Merriam-Webster Online Dictionary