Emergent Disaster Precursive Phenomena and Motion Prediction of the Giant Jinnosuke-dani Landslide in Haku-san Mountain, Japan

神之助大谷滑坡是日本白山地区一个长2,000米、宽500米的巨型滑坡。这也是第一次根据“日本滑坡预防法”指定为“滑坡预防区”的滑坡。该滑坡由Tedori地层中的砂岩和页岩交替层组成，Tedori地层是从侏罗纪时期到早白垩世沉积的。根据7年多来的变形监测成果，将滑坡划分为上、下两个块体。上块体以80至170毫米/年的速度移动，而下块体移动得更慢（3至15毫米/年）。监测资料表明，地下水位的变化对滑坡的运动有很大的影响。通过钻孔勘探和监测，证实了砂泥岩互层风化对滑坡变形的恶化作用。 关于我们 潜在的滑坡发生，滑坡运动预测程序的开发和改进。通过对1934年发生的北斗滑坡的反分析，得到了滑坡运动时的参数，并将其应用于神之助大尼滑坡的运动预测。结果表明，滑坡体冲入铁鸟川水库的危险性很大，预警的必要性很高。2004年5月，阵之助大谷滑坡体右侧发生滑坡，滑坡体流化后转化为泥石流。通过对泥石流监测视频图像的分析、对滑坡源区的实地调查以及对泥石流诱发滑坡的起动和运动过程的环剪仪模拟试验，研究了沟内泥石流的起动和运动机理。结果表明，集中的地下水流是滑坡发生的主要原因，即使在自然排水条件下，动员抗剪强度的急剧下降也是导致滑坡快速运动的主要原因。泥石流在山谷中运动时，上游堆积物的高破碎势和下游堆积物的低破碎势控制了泥石流的运动和停止过程。沟道存款的不同颗粒破碎潜力在泥石流的行进和停止过程中起着重要的作用。少

The Jinnosuke-dani landslide is a giant landslide 2,000 m long and 500 m wide in the Haku-san Mountain area, Japan. It was also the first landslide to be designated as a "Landslide Prevention Area" according to the "Japan Landslide Prevention Law". This landslide consists of alternating layers of sandstone and shale in the Tedori Formation, which was deposited from the Jurassic period to the Early Cretaceous. Based on deformation monitoring results for more than 7 years, the landslide is divided into upper and lower blocks. The upper block has moved at a speed of 80 to 170 mm/year, while the lower block has moved more slowly (3 to 15 mm/year). Monitoring data show that the variation of the groundwater level has a great influence on the landslide movement. The deteriorating effect of the weathering of the alternating layers of sandstone and shale on the landslide deformation has been confirmed by borehole exploration and monitoring.Concerning the landslide motion prediction when a giant … More potential landslide occurs, a prediction program for landslide motion was developed and improved. Through a back-analysis on the Bettou Failure occurred in 1934, the parameter of landslide during motion was obtained, and then used in the motion prediction on the Jinnosuke-dani landslide. The result shows that it is with high risk for the sliding mass rushes into the Tedori-gawa dam reservoir, and shows the high necessity of early -warning.In May 2004, a landslide occurred at the right flank of the Jinnosuke-dani landslide ; this slide was transformed into a debris flow after fluidization. By analysis of the monitored video images of the debris flow, field investigation of the source area of the landslide, and a series of simulation tests with a ring-shear apparatus on the initiation of the rainfall-induced landslide and its traveling process, the initiation and traveling mechanisms of the debris flow traveling in the valley were investigated. It is shown that concentrated groundwater flow was the main reason for the landslide initiation, and a rapid decrease of the mobilized shear resistance even under naturally drained condition caused the rapid landslide motion. During the debris motion in the valley, high potential for grain-crushing of deposits in upstream and lower potential for the downstream deposits controlled the traveling and stopping process. Different grain-crushing potential of the valley deposit played an important role in the debris flow traveling and stopping processes. Less