多源遥感技术在地质灾害早期识别应用中的问题探讨——以西南山区为例

在对滑坡、崩塌等地质灾害的早期识别工作中,基于InSAR、光学遥感、机载LiDAR等多源遥感技术发挥了重要作用。针对应用中出现的一些问题,基于多个项目实践,总结了多源遥感技术在西南山区地质灾害早期识别领域的适用条件,提出了相应的应用建议。主要认识如下: ①InSAR对地质灾害隐患的识别效果受植被覆盖程度、地形条件和数据源类型的制约; 广域InSAR应用中,需注意数据处理关键参数的取舍问题,尽快建立InSAR识别效果的野外判定方法,统一地表形变区“变形程度”和地质灾害InSAR识别效果的评价标准; ②地质灾害光学遥感早期识别适用于“斜坡区域具有明显变形特征”、“历史斜坡灾害”、“泥石流灾害和潜在泥石流沟”这3种类型,在具体应用中应根据不同工作任务要求,选取适合的数据源,注意对地质环境背景条件的分析,不挑战“微变形”探测短板; ③相比较InSAR和光学遥感,机载LiDAR在高密度植被覆盖区地质灾害早期识别方面优势明显,在具体应用中,建议激光点云密度不少于30~50处/m²; ④贴近摄影测量技术适用于高位崩塌(危岩体)早期识别,该技术属于光学遥感范畴,识别效果同样受植被覆盖程度影响,在具体应用中应设置合理探测距离,其具体数值需根据危岩壁分布情况进行调整,建议不小于30 m; ⑤提出了“多源遥感技术手段综合应用,优势互补”“工作部署多层次布置”“注重交叉学科应用及解译人员综合培养”“尽快开展地质灾害信息化获取能力建设”等应用建议。

Application discussion on early identification of geohazards based on multi-source remote sensing technology: A case study on mountainous areas of southwestern China

In the early identification of geological disasters such as landslides and collapses, multi-source remote sensing technologies based on InSAR, optical remote sensing, and airborne LiDAR have played an important role. In view of some problems in the application, based on the practice of many projects, the authors in this paper summarized the applicable conditions of multi-source remote sensing technology in the field of early identification of geohazards in mountainous areas of southwestern China, and put forward corresponding application suggestions. The main understandings are as follows: ① The InSAR identification effect of potential geohazards is restricted by vegetation coverage, terrain conditions and data source types. And it should be paid attention to the chosen of key data processing parameters in the application of wide-area InSAR. Besides, it is necessary to establish the field judgment methods for the InSAR identification as soon as possible, and unify the evaluation criteria of the “deformation degree” of the surface deformation area and the InSAR identification. ② The early identification of geohazards by optical remote sensing is suitable for the three types, including slope area with obvious deformation characteristics, historical slope geohazard, debris flow and potential debris flow ditch. Appropriate data sources should be chosen according to the requirements of different work tasks. And the analysis of the background conditions of the geological environment should be paid attention, while the shortcoming of “micro-deformation” detection should not be challenged. ③ Airborne LiDAR has obvious advantages in early identification of geohazards in high-density vegetation coverage areas, comparing with InSAR and optical remote sensing. The laser point cloud density should be no less than 30-50 points/m² in actual applications. ④ Nap-of-the-object photogrammetry technology is suitable for early identification of high-position collapse (dangerous rock mass), which belongs to the category of optical remote sensing, and its identification effect is also affected by the degree of vegetation coverage. The reasonable detection distance should be set in application and specific value of distance can be adjusted according to the regularity of the dangerous rock wall, which is recommended to be no less than 30 meters. ⑤ Suggestions were proposed, including the comprehensive application of multi-source remote sensing technology and methods with complementary advantages, multi-level arrangement of work deployment, focusing on interdisciplinary application and comprehensive training of interpreters and establishment of geohazards information acquisition capacity progress as soon as possible.