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Scarp retreat is a geological process through which the location of an escarpment changes over time. Typically the cliff is undermined, rocks fall and form a talus slope, the talus is chemically or mechanically weathered and then removed through water or wind erosion, and the process of undermining resumes. Scarps may retreat for tens of kilometers in this way over relatively short geological time spans, even in arid locations. ==Scarp profiles== A scarp is a line of cliffs that has usually been formed by faulting or erosion. If it is protected by a strong caprock, or if it contains vertical fractures, it may retain its steep profile as it retreats. Scarps in dry climates typically have a near-vertical upper face, that may account for 10% - 75% of the total height, with a talus-covered sloping rampart forming the lower section. The caprock is undermined as the rampart and face are eroded, and eventually a section collapses. A strong caprock will typically create a relatively high cliff, since more undermining is needed to cause it to fail. Other factors determining how easily a cliff will fail are the bedding and jointing, direction of dip and thickness of the caprock. A thin caprock will result in low cliffs that retreat quickly. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「scarp retreat」の詳細全文を読む スポンサード リンク
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