Abstract. Floods have occurred frequently all over the world. During 2000–2020, nearly half (44.9 %) of global floods occurred in the Belt and Road region because of its complex geology, topography, and climate. However, the degree of flood susceptibility of each sub-region and country in the Belt and Road region remains unclear. Here, based on 11 flood condition factors, the support vector machine (SVM) model was used to generate a flood susceptibility map. Then, we introduced the flood susceptibility comprehensive index (FSCI) for the first time to quantify the flood susceptibility levels of the sub-regions and countries in the Belt and Road region. The results reveal the following. (1) The SVM model used in this study has an excellent accuracy, and the AUC values of the success-rate curve and prediction-rate curve were higher than 0.9 (0.917 and 0.934 respectively). (2) The areas with the highest and high flood susceptibility account for 12.22 % and 9.57 % of the total study area respectively, and these areas are mainly located in the southeastern part of Eastern Asia, almost the entirely of Southeast Asia and South Asia. (3) Of the seven sub-regions in the Belt and Road region, Southeast Asia is most susceptible to flooding and has the highest FSCI (4.49), followed by South Asia. (4) Of the 66 countries in this region, 16 of the countries have the highest flood susceptibility level (normalized FSCI > 0.8) and 5 countries (normalized FSCI > 0.6) have a high flood susceptibility level. These countries need to pay more attention to flood mitigation and management. The above findings provide useful information for decision-making in flood management in the Belt and Road region. In the future study, higher quality flood points, and climate change factors should be considered.

中文翻译：

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基于支持向量机的“一带一路”地区洪水敏感性评价。

摘要。洪水在世界各地屡屡发生。在2000年至2020年期间，由于“一带一路”地区的地质，地形和气候复杂，全球将近一半（44.9％）的洪灾发生在“一带一路”地区。但是，“一带一路”地区每个分区和国家的洪水敏感性程度仍不清楚。在此，基于11个洪水条件因素，使用支持向量机（SVM）模型生成洪水敏感性图。然后，我们首次引入了洪水敏感性综合指数（FSCI），以量化“一带一路”地区次区域和国家的洪水敏感性水平。结果揭示了以下内容。（1）本研究使用的SVM模型具有极好的准确性，成功率曲线和预测率曲线的AUC值均高于0.9（0.917和0。分别为934）。（2）洪灾敏感性最高和最高的地区分别占研究总面积的12.22％和9.57％，这些地区主要位于东亚的东南部，几乎整个东南亚和南亚。（3）在“一带一路”地区的七个子区域中，东南亚最容易遭受洪水泛滥，FSCI最高（4.49），其次是南亚。（4）在该地区的66个国家中，有16个国家的洪水敏感性水平最高（标准FSCI> 0.8），有5个国家（标准的FSCI> 0.6）具有较高的洪水敏感性。这些国家需要更加重视防洪和管理。以上发现为“一带一路”地区的洪水管理决策提供了有用的信息。