Inventory of landslides and susceptibility mapping in the Dessie area, northern Ethiopia
Inventory of landslides and susceptibility mapping in the Dessie area, northern Ethiopia
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DOI：
10.1016/j.enggeo.2004.07.002
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发表时间：
2005-02
影响因子：
7.4
通讯作者：
T. Ayenew;G. Barbieri
中科院分区：
文献类型：
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作者：
T. Ayenew;G. Barbieri
在埃塞俄比亚北方的德西市及其周围地区对滑坡过程进行了全面研究。研究区由一个由陡峭的断层陡坎和高度风化的第三纪玄武岩覆盖第四纪沉积物的地堑。提出了一种适用于面积约16 km ~ 2山坡的滑坡易发性制图方法。首先，通过将该区域划分为具有类似滑动敏感性的离散数量的较小单元来进行初步分区，然后对导致单元对滑坡活动敏感性的地质、岩土工程、地貌、水文地质和人为因素进行半定量实地调查。最后的滑坡敏感性地图完成了使用经典的叠加程序建立的地图代表不同的影响因素。该方法的有效性进行了检查的滑坡灾害地图，显示了实际分布的滑坡事件发生在过去的手段。最后，确定了4个广泛的滑坡易感区和22个特定的活动滑坡站点。最重要的滑坡类型是与高度风化玄武岩上的冲积和崩积沉积物有关的粉质粘土中的复杂的泥土和泥石流。完整的玄武质岩石在陡坡地区经历了岩石崩塌和倾倒。大规模的滑坡主要是由雨季的地表水和地下水引起的。
A comprehensive study of landslide processes was carried out in the city of Dessie and its environs in northern Ethiopia. The study area consists of a graben bounded by steep fault scarps and characterized by highly weathered Tertiary basaltic rocks covered with Quaternary deposits. A method of landslide susceptibility mapping that adapts to the area of the hillside (about 16 km2) is presented. First, a preliminary zoning was made by dividing the area into a discrete number of smaller units having similar susceptibility to sliding, followed by semi-quantitative field investigation of the geological, geotechnical, geomorphological, hydrogeological, and anthropogenic factors that contribute to the susceptibility of the units to landslide activity. The final landslide susceptibility map was accomplished by using classical overlay procedures of established maps representing the different influencing factors. The validity of the method was checked by means of a landslide-hazard map that showed the actual distribution of landslide episodes that have occurred in the past. Finally, four broad landslide susceptibility zones and 22 specific active landslide sites were identified. The most important landslide types were complex earth and debris slides and flows in silty clay soils associated with alluvial and colluvial deposits overlying highly weathered basalts. Intact basaltic rocks experienced rock fall and toppling in steep slope areas. Large-scale landslides have been initiated mostly by surface water and groundwater during the wet season.