Effect of forest clear-cutting on landslide occurrences: Analysis of rainfall thresholds at Mt. Ichifusa, Japan
Effect of forest clear-cutting on landslide occurrences: Analysis of rainfall thresholds at Mt. Ichifusa, Japan
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DOI：
10.1016/j.geomorph.2016.09.024
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发表时间：
2017
期刊：
影响因子：
3.9
通讯作者：
H. Saito;W. Murakami;H. Daimaru;T. Oguchi
中科院分区：
文献类型：
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作者：
H. Saito;W. Murakami;H. Daimaru;T. Oguchi
植被覆盖是滑坡发生的重要因素。我们分析了森林皆伐对滑坡的启动经验降雨强度持续时间（ID）阈值在山。一房，日本，其特点是花岗岩。20世纪60年代后期，为了森林工业，在山的北方部分进行了大规模的皆伐。一房这一次的皆伐导致了降雨引发的频繁的浅层山体滑坡。我们解释了正射校正航空照片从1969年，1976年，1980年，1985年，1990年，1995年，1999年和2005年使用GIS和地图的基础上，这些照片的滑坡。然后我们分析了暖季（4 - 10月）的所有降雨事件。1952-2011年（60年）的平均降雨量。我们使用的基本降雨参数，如平均降雨强度（I，毫米/小时）和持续时间（D，小时），并估计这些降雨条件的重现期。我们调查了航空照片所代表的每个时期的滑坡发生的绝对I-D阈值，并评估了滑坡发生与10米DEM地形特征之间的关系。结果表明，在1976年以前，皆伐后发生了几次滑坡，但在1976-1980年、1980-1985年和1990-1995年期间发生最频繁。近年来，皆伐区的陡坡和缓坡发生了大量的滑坡，而非皆伐区的滑坡很少。降雨分析表明，皆伐后的植被I-D阈值下降到非皆伐区的一半。在皆伐区，这些连续性I-D阈值的重现期在短时间内（< 12小时）也降至约1年，在短时间内（72小时）降至< 3年。我们的研究结果强调了大量的滞后效应之间的皆伐和山体滑坡发生在山。一房
Vegetation cover is an important factor for rainfall-induced landslides. We analyzed the effect of forest clear-cutting on the initiation of landslides using empirical rainfall intensity–duration (I–D) thresholds at Mt. Ichifusa, Japan, which is characterized by granitic rocks. Extensive clear-cutting was conducted for the forest industry during the late 1960s in the northern part of Mt. Ichifusa. This single episode of clear-cutting caused frequent shallow landslides triggered by rainfall. We interpreted orthorectified aerial photographs from 1969, 1976, 1980, 1985, 1990, 1995, 1999, and 2005 using GIS and mapped landslides based on these photographs. We then analyzed all rainfall events of the warm seasons (Apr.–Oct.) of 1952–2011 (60 years) based on hourly rain gauge data. We used basic rainfall parameters such as mean rainfall intensity (I, mm/h) and duration (D, h) and estimated the return periods of these rainfall conditions. We investigated rainfallI–Dthresholds for landslide occurrences in each period represented by the aerial photographs and assessed the relationships between landslide occurrences and topographic characteristics from 10-m DEMs. The results show that several landslides occurred after clear-cutting before 1976 but that they have occurred most frequently during the periods 1976–1980, 1980–1985, and 1990–1995. Numerous landslides occurred in these years at steeper and gentler slopes in the clear-cut area, but few landslides occurred in the non-clear-cut area. Rainfall analysis demonstrates that rainfallI–Dthresholds after clear-cutting declined to half of those of the non-clear-cut area. The return periods of these rainfallI–Dthresholds also declined to ~ 1 year for short durations of < 12 h and to < 3 years for 72 h in the clear-cut area. Our findings underscore the substantial hysteresis effects between clear-cutting and landslide occurrences at Mt. Ichifusa.