Small unmanned aerial vehicles have been seeing increased deployment in field surveys in recent years. Their portability, maneuverability, and high-resolution imaging are useful in mapping surface features that satellite- and plane-mounted imaging systems could not access. In this study, we develop and apply a workplan for implementing UAV surveys in post-disaster settings to optimize the flights for the needs of the scientific team and first responders. Three disasters caused by geophysical hazards and their associated surface deformation impacts were studied implementing this workplan and was optimized based on the target features and environmental conditions. An earthquake that caused lateral spreading and damaged houses and roads near riverine areas were observed in drone images to have lengths of up to 40 m and vertical displacements of 60 cm. Drone surveys captured 2D aerial raster images and 3D point clouds leading to the preservation of these features in soft-sedimentary ground which were found to be tilled over after only 3 months. The point cloud provided a stored 3D environment where further analysis of the mechanisms leading to these fissures is possible. In another earthquake-devastated locale, areas hypothesized to contain the suspected source fault zone necessitated low-altitude UAV imaging below the treeline capturing Riedel shears with centimetric accuracy that supported the existence of extensional surface deformation due to fault movement. In the aftermath of a phreatomagmatic eruption and the formation of sub-metric fissures in nearby towns, high-altitude flights allowed for the identification of the location and dominant NE–SW trend of these fissures suggesting horst-and-graben structures. The workplan implemented and refined during these deployments will prove useful in surveying other post-disaster settings around the world, optimizing data collection while minimizing risk to the drone and the drone operators.

中文翻译：

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通过小型无人机对灾后环境中的地表变形进行成像

近年来，小型无人机在实地调查中的部署有所增加。它们的便携性、机动性和高分辨率成像对于绘制卫星和平面安装成像系统无法访问的表面特征很有用。在这项研究中，我们制定并应用了在灾后环境中实施无人机调查的工作计划，以优化飞行以满足科学团队和急救人员的需求。实施该工作计划研究了由地球物理灾害及其相关地表变形影响引起的三种灾害，并根据目标特征和环境条件进行了优化。在无人机图像中观察到一次地震导致河流附近的房屋和道路横向蔓延并损坏，长度长达 40 m，垂直位移为 60 cm。无人机勘测捕获了 2D 航空栅格图像和 3D 点云，导致这些特征在仅 3 个月后被耕种的软沉积地面中得以保留。点云提供了一个存储的 3D 环境，可以在其中进一步分析导致这些裂缝的机制。在另一个遭受地震破坏的地区，假设包含可疑源断层带的区域需要在树线下方进行低空无人机成像，以厘米精度捕获里德尔剪切，以支持由于断层运动导致的伸展表面变形的存在。在潜水岩浆喷发和附近城镇亚米级裂缝的形成之后，高空飞行可以识别这些裂缝的位置和主要的 NE-SW 趋势，表明地堑结构。在这些部署期间实施和完善的工作计划将被证明有助于调查世界各地的其他灾后环境，优化数据收集，同时最大限度地降低无人机和无人机操作员的风险。