联合SBAS-InSAR和PSO-BP算法的高山峡谷区地质灾害危险性评价

    Combined SBAS-InSAR and PSO-BP algorithm for evaluating the risk of geological disasters in alpine valley regions

    • 摘要: 近年来,高山峡谷区地质灾害频频发生,给人民生命和财产安全带来严重威胁。针对现有地质灾害评价方法存在地质灾害数据时效性差、不准确以及需进行大量评价因子权值计算等弊端,该研究提出一种联合SBAS-InSAR(Small Baseline Subsets- Interferometric Synthetic Aperture Radar)和PSO-BP(Particle Swarm Optimization-Back Propagation)算法来对高山峡谷区地质灾害危险性进行评价的方法。首先利用SBAS-InSAR技术获取得到研究区升降轨形变量,引入高分辨率影像等作为辅助识别,得到研究区地质灾害数据;然后,选取高程、坡度、升降形变速率等12个评价因子与是否为高危险区构建PSO-BP模型,对模型进行训练、验证并保存模型;利用保存好的模型得到研究区的地质灾害指数,通过ArcGIS自然间断点分级法结合专家参与进行危险性分级,最终得到研究区地质灾害危险性评价结果。试验结果表明:利用升降轨结合的方式对高山峡谷地质灾害进行识别,避免了单一轨道存在SAR成像几何畸变造成部分地质灾害不能识别或识别结果不全面等问题;利用SBAS-InSAR技术并结合高分辨率影像等辅助信息,可有效识别出活跃的泥石流、滑坡、崩塌和潜在地质灾害,解决了现有地质灾害点数据源时效性差、不准确等弊端;利用PSO-BP算法能跳过大量评价因子权值计算等弊端;为验证该研究方法的有效性,选择信息量法和组合赋权法进行定量和定性比较,结果表明,该研究方法有效的提高了地质灾害危险性评价的准确度,信息量法、组合赋权法和该研究方法的AUC(Area Under The Curve)值分别为0.694、0.721、0.785,准确率为73.3%、76.2%、79.8%。利用该方法能更为有效的对高山峡谷区地质灾害进行危险性评价,为防灾减灾事业及政府部门决策提供参考。

       

      Abstract: Geological disasters have posed serious threats to the living, economic security, and local infrastructure, particularly those frequently occurring in the alpine valley regions in recent years. However, the existing evaluation needs to calculate a large number of weighted factors, leading to low timeliness and poor accuracy in the geological disaster data. In this study, a combined SBAS-InSAR (Small Baseline Subsets-Interferometric Synthetic Aperture Radar) and PSO-BP (Particle Swarm Optimization- Back Propagation) algorithm was proposed to evaluate the risk of geological disasters in the alpine valley regions. First, the Small Baseline Subsets-Interferometric Synthetic Aperture Radar (SBAS-InSAR) technology was used to record the deformation rates for the ascending and descending orbits in the study area, where the high-resolution images were captured for the geological disasters data. Next, the Particle Swarm Optimization-Back Propagation (PSO-BP) geological disaster model was trained using the 12 evaluation factors, such as the elevation, slope, ascending and descending deformation rates. Finally, the new model was used to acquire the geological disaster index for the study area. An ArcGIS natural break point grading was used to grade the risk of geological disasters. As such, a risk evaluation was obtained for the validity of the model. The results showed that the combined ascending and descending orbits performed better to identify the geological disasters in the Alpine valley regions, compared with the current single tracks. A more accurate and comprehensive identification of geological disasters was also achieved to avoid the geometric distortion of SAR imaging. Furthermore, the surface shape variables were acquired using the SBAS InSAR technology combined with high-resolution imaging. A rapid and accurate identification was realized to effectively identify the active rock, slippery slope, collapse, and potential geological disasters. A large number of calculations were avoided for the evaluation factors under the PSO-BP method. In addition, informatics and combined empowerment were selected to quantitatively and qualitatively compare the InSAR-ANN model. It was found that the Area Under the Curve (AUC) values of information, combination weighting, and INSAR-ANN were 0.694, 0.721, and 0.785, respectively, and the accuracies were 73.3%, 76.2%, and 79.8%, respectively, indicating the higher efficiency and accuracy of the improved InSAR-ANN model in the risk evaluation on the geological disasters. Consequently, the INSAR-ANN model can be expected to effectively implement a risk assessment of geological disasters in the Alpine canyon areas. This finding can also provide a strong reference for disaster prevention and decision-making mitigation.

       

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