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HIROYUKI OBANAWA YUICHI S. HAYAKAWA YUKINORI MATSUKURA 《Geografiska Annaler: Series A, Physical Geography》2009,91(4):269-278
On the basis of a space–time substitution, rates of cliff retreat and talus development overthe pasttens ofthousands of years were quantified for valley‐side slopes along the Shomyo River with a known rate of waterfall recession. Detailed profiles of the valley‐side slopes were obtained at 19 sites along the river by map reading and field survey, and the morphologic characteristics of the slopes were then measured. By combining the locations of the slopes with the recession rate of Shomyo Falls, it is estimated that the growth rate of the talus slope is 3.9–7.2 mm/yr, the rate of decline of the cliff is 2.0–4.0 × 10?4 deg/yr, and the retreat rate of the cliff top is 6.2–11.6 mm/yr. 相似文献
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YUICHI S. HAYAKAWA HIROYUKI OBANAWA YUKINORI MATSUKURA 《Geografiska Annaler: Series A, Physical Geography》2008,90(1):65-74
Post‐eruptive fluvial erosion of welded pyroclastic flow deposits often depends on the recession of waterfalls because of their rapid erosion involved. We examine the recession rate of Shomyo Falls, which consists of Pleistocene welded pyroclastic flow deposits in Tateyama, north‐central Japan. The mean recession rate of the waterfall obtained from lithological and topographical evidences is 0.08‐0.15 m/a for 100000 a. However, the recession rate estimated by means of an empirical equation comprising physical parameters of erosive force and bedrock resistance is 0.006‐0.011 m/a with small uncertainties. The discrepancy between the geology‐based and equation‐based recession rates indicates that some factors, not taken account of in the equation, significantly influence the recession rate. We suggest that a factor in the rapid erosion of the waterfall is a large amount of transported sediment acting as abrasive material, which is supplied from high mountains in the watershed above the waterfall. 相似文献
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