区域地质灾害易发性分级方法对比分析研究

Comparative Analysis on Classification Methods of Geological Disaster Susceptibility Assessment

  • 摘要: 地质灾害不仅造成了严重的经济损失和生态破坏,同时也威胁着人类的生存。地质灾害易发性评价是地质灾害风险评价的基础,以往的研究中重在探讨易发性评价方法的选取,而对于地质灾害易发性指数如何分级的研究较少。为了探索地质灾害易发性评价精度验证与定量的分级标准,以四川省汶川县为例,选取12种广泛应用的地质灾害易发性影响因子,运用信息量模型进行易发性评价,运用成功率曲线检验模型的评价精度,提出历史地质灾害累计比例分段法,并与其他8种分级方法进行对比分析与分级精度验证。研究结果表明,用验证样本成功率曲线与非灾害点样本成功率曲线两种方法检验模型评价精度确定了评价模型预测结果的合理性。历史地质灾害累计比例分段法在易发性分级面积比例精度验证、地质灾害频率比分级精度验证与发生地质灾害位置分级精度验证3种方式中均显现出较好的合理性,在9种分级方法中为最优分级标准。

     

    Abstract:
      Objectives  Geological hazards not only cause serious economic losses and ecological damage, but also threaten the survival of mankind. The evaluation of geological hazard susceptibility is the basis of risk assessment of geological hazards. Previous studies focused on the selection of susceptibility assessment methods, but less on how to classify the susceptibility index of geological hazards. However, there is no good quantitative classification standard for the susceptibility of geological hazards in the current research results.
      Methods  Taking Wenchuan County of Sichuan Province as an example, twelve widely used factors affecting geological hazard susceptibility was selected, and the susceptibility assessment was carried out by using the information quantity model. The evaluation accuracy of the model was tested by the success rate curve. We proposed a quantitative classification standard for susceptibility. The susceptibility index is a cumulative curve of the proportion of geological hazards in descending order, and the susceptibility index is divided into five intervals: 5% of historical disaster points (low-prone), the remaining 10% (medium-prone), the remaining 20% (high-prone), and the remaining 65% (very-high).
      Results  The method of cumulative proportion subsection of historical geological hazards was compared with other eight methods and the accuracy of classification is verified. The results showed that the evaluation accuracy of the model was checked by two methods of validating the sample success rate curve and the non-disaster point sample success rate curve, and the rationality of the prediction results of the evaluation model was determined. The cumulative proportion subsection method of historical geological hazards showed good reasonableness in three ways: The proportion accuracy verification of vulnerable classification area, the frequency ratio accuracy verification of geological hazards and the location classification accuracy verification of geological hazards. It was the best classification standard in nine classification methods.
      Conclusions  The quantitative classification standard for the susceptibility of geological hazards established in this article has a good application effect, but this standard needs more examples to verify. Geological hazard susceptibility evaluation is based on a good factor classification. Research work needs not only to focus on scientific and advanced evaluation methods, but also basic research on how to select factors and rational classification of factors.

     

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