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In mechanics and geodynamics, a critical taper is the equilibrium angle made by the far end of a wedge-shaped agglomeration of material that is being pushed by the near end. The angle of the critical taper is a function of the material properties within the wedge, pore fluid pressure, and strength of the fault (or décollement) along the base of the wedge. In geodynamics the concept is used to explain tectonic observations in accretionary wedges. Every wedge has a certain "critical angle", which depends on its material properties and the forces at work.〔Chapple (1978)〕〔Davis ''et al.'' (1983)〕 This angle is determined by the ease by which internal deformation versus slip along the basal fault (décollemont) occurs. If the wedge deforms more easily internally than along the décollement, material will pile up and the wedge will reach a steeper critical taper until such a point as the high angle of the taper makes internal deformation more difficult than sliding along the base. If the basal décollement deforms more easily than the material does internally, the opposite will occur. The result of these feedbacks is the stable angle of the wedge known as the critical taper. When natural processes (such as erosion, or an increase in load on the wedge due to emplacement of a sea or ice cap) change the shape of the wedge, the wedge will react by internally deforming to return to a critically tapered wedge shape. The critical taper concept can thus explain and predict phases and styles of tectonics in wedges. An important presumption is that the internal deformation of the wedge takes place by frictional sliding or brittle fracturing and is therefore independent of temperature.〔Davis ''et al.'' (1983)〕 ==Mechanical quantification== The critical taper concept assumes mechanical equilibrium, which means the compressional force (the tectonic push) that created the wedge will be equal to the resisting forces inside the wedge. 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「Critical taper」の詳細全文を読む スポンサード リンク
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