Prevention of disasters due to the chemical compositions of the rocks in the slope failures damaged by the Hyogoken-Nanbu Earthquake

许多陡峭的斜坡在Hyogoken-Nanbu地震中遭到严重破坏。神户地区的陡坡一直受到断层的强烈侵蚀，风化程度很深。坍塌是在降雨期间蔓延的。认为该区边坡破坏集中的原因是严重的破碎和风化作用。在边坡失稳的风化过程中，元素从岩石中淋失。在此过程中，岩石中的MgO、CaO和FeO含量显著降低。这些元素在黑云母中的淋溶作用是显著的，因为黑云母在水存在的情况下会变成蛭石和高岭石。岩石的化学成分均在坡面上反映风化程度。因此，化学成分对防止边坡的破坏是有用的。边坡的破坏似乎集中在矿脉上。斜坡上的花岗岩被认为是在热液作用下蚀变为粘土矿物。花岗岩中的黑云母很容易被风化，在水的存在下，黑云母易转变为粘土矿物。花岗岩边坡中的矿脉与边坡失稳密切相关。

Many steep slopes were heavy damaged by the Hyogoken-Nanbu Earthquake. The steep slopes in Kobe district has been so strongly by the fault and been weathered deeply. The collapse has been spread during the rainfalls. The reason for the slope failure concentration is thought to be heavy crushed and weathering in this area. The element are leached from the rocks during the wethering process of the slope failure. MgO, Cao and Feo contents in the rocks are remarkably decrease during the process. Leaching of these elements is remarkable in biotite, because the biotite alters in the presence of water to vermiculite and kaolinite. Chemical composition of the rocks are in the slope reflect to weathering grade. Thus, chemical composition are useful for prevention of the slope failures. The slope failures appear to be concentrated along the vein. The granitic rocks of the slopes are thought to be alteration to clay minerals at hydrothermal. Biotite in granitic rocks is easily weathered and alters in the presence of water to clay minerals. There is a close relation between slope failure and the vein in the granitic slopes.