Assessment of rockfall susceptibility by integrating statistical and physically-based approaches
Assessment of rockfall susceptibility by integrating statistical and physically-based approaches
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DOI：
10.1016/j.geomorph.2006.10.037
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发表时间：
2008-02
期刊：
影响因子：
3.9
通讯作者：
P. Frattini;G. Crosta;A. Carrara;F. Agliardi
中科院分区：
文献类型：
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作者：
P. Frattini;G. Crosta;A. Carrara;F. Agliardi
在瓦尔迪法萨（意大利东部阿尔卑斯山的多洛米蒂），落石是最严重的重力引起的自然灾害，威胁着山谷中为数不多的居民和成千上万的游客。为了评估落石的敏感性，我们开发了一个综合的统计和物理为基础的方法，旨在预测发病的敏感性和概率，落石将达到特定的范围。通过实地检查和多时间航空照片的解释，我们准备了一份详细的清单，既落石源区和相关的碎石斜坡沉积。使用基于GIS工具和三维落石模拟代码的创新技术，将落石源区域多边形的网格单元根据相关碎石斜坡沉积物的活动状态分类为活动或非活动。模拟代码允许一个链接每个源网格单元与碎石存款多边形通过计算每个模拟发射块的轨迹。通过判别分析，然后，我们确定了最好的识别低或高的易感性落石的网格单元的环境变量的组合。在这些变量中，结构设置，土地利用，和形态是最重要的因素，导致开始落石。我们开发了落石的跳动距离、强度和频率的3D模拟模型，其源网格单元对应于地貌定义的源多边形（地貌场景）或研究坡度大于地貌定义值37°的区域网格单元（经验场景）。对于每一种情况下，我们分配给源网格细胞的固定或可变的发病易感性，后者是来自判别模型组（活跃/不活跃）的成员资格概率。这四个模型的比较表明，地貌情景与可变的发病敏感性似乎是最现实的模型。然而，政治和法律的问题似乎指导着地方行政人员，他们倾向于选择更保守的基于土地的设想作为土地规划工具。
In Val di Fassa (Dolomites, Eastern Italian Alps) rockfalls constitute the most significant gravity-induced natural disaster that threatens both the inhabitants of the valley, who are few, and the thousands of tourists who populate the area in summer and winter. To assess rockfall susceptibility, we developed an integrated statistical and physically-based approach that aimed to predict both the susceptibility to onset and the probability that rockfalls will attain specific reaches. Through field checks and multi-temporal aerial photo-interpretation, we prepared a detailed inventory of both rockfall source areas and associated scree-slope deposits. Using an innovative technique based on GIS tools and a 3D rockfall simulation code, grid cells pertaining to the rockfall source-area polygons were classified as active or inactive, based on the state of activity of the associated scree-slope deposits. The simulation code allows one to link each source grid cell with scree deposit polygons by calculating the trajectory of each simulated launch of blocks. By means of discriminant analysis, we then identified the mix of environmental variables that best identifies grid cells with low or high susceptibility to rockfalls. Among these variables, structural setting, land use, and morphology were the most important factors that led to the initiation of rockfalls. We developed 3D simulation models of the runout distance, intensity and frequency of rockfalls, whose source grid cells corresponded either to the geomorphologically-defined source polygons (geomorphological scenario) or to study area grid cells with slope angle greater than an empirically-defined value of 37° (empirical scenario). For each scenario, we assigned to the source grid cells an either fixed or variable onset susceptibility; the latter was derived from the discriminant model group (active/inactive) membership probabilities. Comparison of these four models indicates that the geomorphological scenario with variable onset susceptibility appears to be the most realistic model. Nevertheless, political and legal issues seem to guide local administrators, who tend to select the more conservative empirically-based scenario as a land-planning tool.