Quantitative Study of the Slope Development of Fluvial Terrace Scarps

用单位跨度为2米的坡度廓线仪在秩父盆地的河流基岩-阶地陡坡以及西河和爱河沿岸进行了坡度剖面测量。阶地陡坡高度为2.5 ~ 90 m，平均倾角为7 ~ 90°，陡坡年代为0.5 ~ 30 ka b.p.。基岩为白垩系和第三系沉积岩，真倾角为15 ~ 90‰。大部分剖面分为三段：结晶凸段、中间直段和基底凹段。根据实际测量和估计的断崖年龄、断崖初始高度、基岩的反射倾角和力学性质以及气候条件等变量，确定了任意地点和给定时间的断崖下降速率和每段断崖高比变化率。

Slope profiles were measured with a slope profiler having a unit span of 2 meters on the fluvial bedrock-terrace scarps in the Chichibu Basin and along the Sai and Oi Rivers. The terrace scarps studied range from 2.5 m to 90 m in height, from 7 to 90 degree in mean angle, and from 0.5 ka B. P. to 30 ka B. P. in the scarp age. The bedrocks are Cretaceous and Tertiary sedimentary rocks ranging from 15ﾟ to 90ﾟ in true dip. Most of the profiles were divided into three segments : crstal convex, middle straight and basal concave segments.The rate of slope decline and the rate of changes in the height ratio of each of the three segments at an arbitrary site and at a given time were formulated in terms of the practically measured and estimated variables such as scarp age, initial height of scarp, retive dip and mechanical properties of bedrock, and climatic condition.