Temporal and spatial variation of infilling processes in a landslide scar in a steep mountainous region, Japan
Temporal and spatial variation of infilling processes in a landslide scar in a steep mountainous region, Japan
复制标题
DOI：
10.1002/esp.3659
复制
发表时间：
2015-04
影响因子：
3.3
通讯作者：
F. Imaizumi;R. Sidle;Asako Togari‐Ohta;M. Shimamura
中科院分区：
文献类型：
--
作者：
F. Imaizumi;R. Sidle;Asako Togari‐Ohta;M. Shimamura
在潮湿地区的给定地点，浅层崩积滑坡再次发生所需的土壤深度恢复持续时间远长于产生足够孔隙水压力以引发滑坡所需的降雨重现期。因此，滑坡疤痕土壤深度的变化率的知识是必要的，以评估滑坡的重现期。通过野外观测，研究了日本中部熊野平滑坡遗迹泥沙输运的空间变化。利用泥沙输移数据和地理信息系统（GIS）分析，估算了土壤深度变化率的空间分布。观测结果表明，沉积物迁移的时间在浅层和深层土壤中不同。在沉积物收集器中测量的近地表沉积物输运（主要是干燥的碎屑和深度≤ 0.05 m的一些浅层土壤蠕变）在冬季和早春活跃，并受到冻融的影响;由应变探针监测的底土（即> 0.05 m）的土壤蠕变在夏季和秋季降水充足时活跃。近地表泥沙通量由坡度的幂律函数估算。滑坡体相对位置对土体深度的影响大于坡度对土体深度的影响。我们的研究表明，土壤深度恢复率在滑坡头崖下方很高。由于滑坡头崖和侧翼附近的退化以及头崖下方的加积，头崖上方、内部和下方的纵坡地形的突变随着时间的推移变得更加平滑。版权所有© 2014约翰威利父子有限公司.
The duration of the soil‐depth recovery needed for reoccurrence of shallow colluvial landslides at a given site in humid regions is much longer than the return period of rainfall needed to generate sufficient pore water pressure to initiate a landslide. Knowledge of the rate of change in soil depth in landslide scars is therefore necessary to evaluate return intervals of landslides. Spatial variation in sediment transport at the Kumanodaira landslide scar in central Japan was investigated by field observations. Spatial distribution of the rate of change in soil depth was estimated using sediment transport data and geographic information system (GIS) analysis. Observations revealed that the timing of sediment transport differed for shallow and deep soil layers. Near‐surface sediment transport (mostly dry ravel and some shallow soil creep at depths ≤0·05 m) measured in sediment traps was active in winter and early spring and was affected by freezing–thawing; soil creep of subsoil (i.e. >0·05 m), monitored by strain probes, was active in summer and autumn when precipitation was abundant. Near‐surface sediment flux was estimated by a power law function of slope gradient. Deeper soil creep was more affected by relative location to the landslide scar, which influences soil depth, than by slope gradient. Our study indicated that the rate of soil‐depth recovery is high just below the head scarp of the landslide. Abrupt changes in the longitudinal slope topography immediately above, within and just below the head scarp became smoother with time due to degradation proximate to the landslide head scarp and flanks, as well as aggradation just below the head scarp. Copyright © 2014 John Wiley & Sons, Ltd.