Discovery, controls, and hazards of widespread deep-seated gravitational slope deformation in the Etsumi Mountains, central Japan
Discovery, controls, and hazards of widespread deep-seated gravitational slope deformation in the Etsumi Mountains, central Japan
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日本中部越海山脉广泛的深层重力斜坡变形的发现、控制和危害
DOI：
10.1002/2017jf004382
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发表时间：
2017
期刊：
影响因子：
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通讯作者：
Kaneda. H. and T. Kono
中科院分区：
文献类型：
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作者：
庭野匡思;橋本明弘;青木輝夫;石澤広明;米村滋人;Yuji Yamada;堀尾正靱・歌川学;Ryo Hemmi and Takeshi Saito;Kaneda. H. and T. Kono
深层重力斜坡变形（DSGSD）是一个很大程度上未被注意到但重要的长期质量浪费过程，可能导致山坡的灾难性破坏。它表现为小的地形不规则性，例如与山脊平行的陡坡和线性凹陷，主要发生在林线以上的高山景观中。根据通过光探测和测距（激光雷达）调查获得的全区域高分辨率地形数据，我们在此表明，日本中部越美山脉约 96% 的现有重力陡坡隐藏在森林树冠下。陡坡在山脉中分布广泛，平均线密度高达 0.87 公里/平方公里。我们对陡坡分布的分析表明，上坡陡坡是 DSGSD 的主要地貌信号，其失稳岩体大于约 105 平方米，而下坡陡坡主要是响应更局部的边坡变形而出现的。在控制方面，地形是迄今为止触发和促进 DSGSD 最具影响力的因素。尽管1891年发生了7.5级地震，但局部大地震的影响并不是很强。与现有滑坡地图的比较进一步表明，DSGSD 和大规模滑坡并不是不同的斜坡过程，而是代表同一过程的不同阶段。我们的结果强调了森林覆盖山区航空摄影解释的局限性，以及激光雷达辅助测绘的必要性，以更深入地了解这一长期过程以及地表和构造过程之间的相互作用。
Deep‐seated gravitational slope deformation (DSGSD) is a largely unnoticed but important long‐term mass wasting process that may result in catastrophic failure of mountain slopes. Manifested by small topographic irregularities such as ridge‐parallel scarps and linear depressions, it has been predominantly reported in alpine landscapes above timber lines. On the basis of area‐wide high‐resolution topographic data acquired by light detection and ranging (lidar) surveys, we here show that ~96% of existing gravitational scarps have been hidden under forest canopies in the Etsumi Mountains, central Japan. The scarps are surprisingly widespread over the mountains with a mean line density of as large as 0.87 km/km2. Our analyses of the scarp distribution suggest that uphill‐facing scarps are primary geomorphic signals of DSGSD with a destabilized rock mass larger than ~105m2, whereas downhill‐facing scarps principally occur in response to more localized slope deformation. In terms of controls, topography is by far the most influential factor in triggering and promoting DSGSD. Despite theM7.5 earthquake in 1891, impact of large local earthquakes proves to be not very strong. Comparison with preexisting landslide maps further suggests that DSGSD and large‐scale landslides are not different slope processes but represent different stages of the same process. Our results highlight limitations of aerial‐photograph interpretation in forest‐covered mountains and the need for lidar‐assisted mapping for deeper understanding of this long‐term process and interactions between surface and tectonic processes.