Integrated Sentinel‐1 InSAR and GNSS Time‐Series Along the San Andreas Fault System
Integrated Sentinel‐1 InSAR and GNSS Time‐Series Along the San Andreas Fault System
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DOI：
10.1029/2021jb022579
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发表时间：
2021-11
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影响因子：
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通讯作者：
Xiaohua Xu;D. Sandwell;E. Klein;Y. Bock
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作者：
Xiaohua Xu;D. Sandwell;E. Klein;Y. Bock
测量地壳应变和地震矩积累，对于理解地震灾害沿着主要断层系统的增长和分布至关重要。在这里，我们开发了一种方法来整合4.5年（2015-2019.5）的Sentinel-1干涉合成孔径雷达（干涉合成孔径雷达）和连续的全球导航卫星系统（GNSS）时间序列，以实现整个圣安德烈亚斯断层系统的地表位移的6至12天采样，空间分辨率为500米。该产品可识别出许多有趣的变形信号（视频链接：https://www.youtube.com/watch? v=SxNLQKmHWpY）。我们通过结合来自GNSS导出的震间断层模型的变形方位角，将视线干涉合成孔径雷达位移分解为三维。然后，我们构建应变率映射使用平滑的弹性约束。由此产生的变形场揭示了广泛的地壳变形过程，包括断层上和断层外的长期和瞬态构造变形，所有主要断层的蠕变速率，以及与水文过程相关的垂直信号。应变率图显示了仅GNSS模型未捕获的重要非故障分量。这些结果对评估该地区的地震危险性具有重要意义。
Measuring crustal strain and seismic moment accumulation, is crucial for understanding the growth and distribution of seismic hazards along major fault systems. Here, we develop a methodology to integrate 4.5 years (2015–2019.5) of Sentinel‐1 Interferometric Synthetic Aperture Radar (InSAR) and continuous Global Navigation Satellite System (GNSS) time series to achieve 6 to 12‐day sampling of surface displacements at ∼500 m spatial resolution over the entire San Andreas fault system. Numerous interesting deformation signals are identified with this product (video link: https://www.youtube.com/watch?v=SxNLQKmHWpY). We decompose the line‐of‐sight InSAR displacements into three dimensions by combining the deformation azimuth from a GNSS‐derived interseismic fault model. We then construct strain rate maps using a smoothing interpolator with constraints from elasticity. The resulting deformation field reveals a wide array of crustal deformation processes including, on‐ and off‐fault secular and transient tectonic deformation, creep rates on all the major faults, and vertical signals associated with hydrological processes. The strain rate maps show significant off‐fault components that were not captured by GNSS‐only models. These results are important in assessing the seismic hazard in the region.