Fluidized landslides triggered by the liquefaction of subsurface volcanic deposits during the 2018 Iburi-Tobu earthquake, Hokkaido
Fluidized landslides triggered by the liquefaction of subsurface volcanic deposits during the 2018 Iburi-Tobu earthquake, Hokkaido
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DOI：
10.1038/s41598-019-48820-y
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发表时间：
2019-09-11
影响因子：
4.6
通讯作者：
Inaoi, Chisaki
中科院分区：
文献类型：
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作者：
Kameda, Jun;Kamiya, Hiro;Inaoi, Chisaki
2018年9月6日，日本北海道南部发生里氏6.6级地震。地震引发了震中附近山区的大面积山体滑坡，造成36人死亡。覆盖该地区的火山沉积物以类似流动的方式向下滑动，暗示着流化滑坡。在这里，我们报告了一个独特的液化的例子，在现场，这可能是一个先决条件，产生流化滑坡引发的大地震。在一个典型的滑坡的陡坎，蚀变埃洛石轴承火山层观察到的水平几乎一致的滑动面。该层是强烈的起伏，可以分为一个上粘土丰富的层和一个下浮石丰富的层，这表明，由于强烈的同震地面运动的蚀变层液化。就在地震前一天，这一层被大雨浸泡，可能液化，产生一个脆弱和湿滑的平面，导致该地区灾难性的山体滑坡。
The 6.6 M-w Iburi-Tobu earthquake struck southern Hokkaido, Japan on 6 September 2018. The earthquake triggered widespread slope collapses in the hills near the epicenter, resulting in destructive landslides that killed 36 people. Volcanic deposits covering the region slid downhill in a flow-like manner suggestive of fluidized landslides. Here, we report a distinctive example of liquefaction in the field, which could be a prerequisite for the generation of fluidized landslides triggered by large earthquakes. In the scarp of a typical landslide, an altered halloysite-bearing volcanic layer is observed at a level almost coincident with the sliding surface. The layer is intensely undulating and can be divided into an upper clay-rich layer and a lower pumice-rich layer, suggesting that the altered layer had liquefied as a result of the strong coseismic ground motion. The layer had been soaked by heavy rainfall just one day before the earthquake and could have liquefied, producing a weak and slippery plane, resulting in the catastrophic landslides in this area.