An Alternative Approach for Constraining 3D‐Displacements With InSAR, Applied to a Fault‐Bounded Groundwater Entrainment Field in California
An Alternative Approach for Constraining 3D‐Displacements With InSAR, Applied to a Fault‐Bounded Groundwater Entrainment Field in California
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DOI：
10.1029/2020jb021137
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发表时间：
2021-04
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影响因子：
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通讯作者：
K. D. Murray;R. Lohman;J. Kim;William E. Holt
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作者：
K. D. Murray;R. Lohman;J. Kim;William E. Holt
探讨了弹性格林函数在干涉合成孔径雷达(InSAR)一维观测数据反演中的应用，以恢复三维位移场。这种方法加强了水平位移的耦合，并限制了对地下震源的预先假设的需要，从而驱动了整个3D变形场的给定维度的变形或显式阻尼。我们将这些方法应用于加利福尼亚州科切拉山谷的数据，2017年那里的人工地下水补给以及相关的孔压增加导致地面位移高达12厘米。这一区域由Sentinel-1a/b数据覆盖，其中包括来自上升和下降轨道的两条重叠路径的数据，以及无人驾驶飞行器合成孔径雷达(UAVSAR)的东西向飞行路线，提供了五种独特的视线几何形状。仅应用于哨兵数据的正则化方法在大多数方面都是一致的，弹性耦合方法对独立的UAVSAR观测产生了稍微更好的拟合。我们的结果表明，2017年科切拉河谷的地下水夹带可能与显著的水平位移有关，这种水平位移导致盆地北侧边界的断层收缩，以及沿断层的一些地区右侧应变感的增加。
We explore the use of elastic Green’s functions in inversions of one‐dimensional Interferometric Synthetic Aperture Radar (InSAR) observations to recover three‐dimensional displacement fields. This approach enforces coupling of the horizontal displacements and limits the need for prior assumptions about the subsurface sources, driving the deformation or explicit damping of a given dimension of the full 3D deformation field. We apply these methods to data from the Coachella Valley, California, where artificial groundwater recharge in 2017 and the associated increases in pore pressure resulted in ground displacements of up to 12 cm. This area is covered by Sentinel‐1a/b data for two overlapping paths from both ascending and descending orbits, as well as an east‐west flight line from the Uninhabited Aerial Vehicle Synthetic Aperture Radar (UAVSAR), providing five unique line‐of‐sight geometries. The regularization approaches applied to the Sentinel data alone agree in most respects, with the elastically coupled approach producing a slightly better fit to the independent UAVSAR observations. Our results suggest that the 2017 groundwater entrainment in the Coachella Valley is likely associated with significant horizontal displacements that led to contraction across the fault bounding the northern side of the basin, as well as increases in right‐lateral sense of strain in some areas along the fault.