Sinkhole processes can be more complicated than vertical drainage or collapse of sediments into an underlying limestone void. To better understand the relationships between surface and underlying karst structures, geodetic and geophysical methods were applied to high-resolution mapping of active sinkhole features in covered karst, west-central Florida, USA. Cracks in a pool house at the Sandhill Scout Reservation prompted surface and subsurface investigations in a grassy open field with a distinct ~60-m diameter topographic low west of the pool area. Beneath the smooth topographic low, ground-penetrating radar (GPR) with limited penetration (up to 6 m depth) shows incongruent smaller-scale (~5–20 m) variability in a horizon draping the limestone surface. Electrical Resistivity Tomography (ERT) profiles provide a broader overview of the underlying karst system (to depths ~25–36 m) and show possible voids in the limestone bedrock beneath a local topographic high. Persistent Scatterer Interferometric Synthetic Aperture Radar (PSInSAR) analysis of ~2 yr of TerraSAR-X satellite data from two corner-reflectors installed in the topographic low reveals a 1 mm/yr subsidence rate on the flank of the topographic low but stability in its center. This suggests that subsidence has halted in the central topographic low and may be occurring on smaller scales elsewhere within the survey area. The data suggest that non-vertical fluxes of sediment significantly smooth surface topography relative to underlying heterogeneities and that activity migrates within complex systems. Our results also illustrate the benefits of corner reflector installations for resolving subsidence in vegetated environments. The 1-mm/yr rate of motion on the grassy field could not be resolved with InSAR before reflector installation.

天坑过程可能比垂直排水或沉积物塌陷到下伏石灰岩空隙中更复杂。为了更好地了解地表和下伏岩溶结构之间的关系，大地测量和地球物理方法被应用于美国佛罗里达州中西部覆盖岩溶的活动天坑特征的高分辨率绘图。Sandhill Scout Reservation 的泳池房出现裂缝，促使在泳池区西侧低处有明显直径约 60 米的开阔草地上进行地表和地下调查。在光滑的地形低、穿透力有限（深度可达 6 m）的探地雷达 (GPR) 下，覆盖石灰岩表面的地平线显示出不一致的小尺度 (~5-20 m) 变化。电阻率层析成像 (ERT) 剖面提供了对底层岩溶系统（深度约 25-36 m）的更广泛概述，并显示了当地地形高点下方石灰岩基岩中可能存在的空隙。持久散射干涉合成孔径雷达 (PSInSAR) 对来自安装在低地形中的两个角反射器的大约 2 年的 TerraSAR-X 卫星数据的分析显示，低地形侧面的沉降率为 1 毫米/年，但其中心稳定. 这表明沉降已经在中央地形低处停止，并且可能在调查区域内的其他地方以较小的尺度发生。数据表明，相对于潜在的异质性，沉积物的非垂直通量显着平滑了表面地形，并且活动在复杂系统内迁移。我们的结果还说明了角反射器安装在解决植被环境下沉的好处。在安装反射器之前，InSAR 无法解决草地上 1 毫米/年的运动速率。