Rings of the Ridgecrest Earthquakes. In Art of Science

Caption: Satellite-based radar imaging captures surface change caused by earthquake motion in eastern California Participant category: Postdoctoral Department: Scripps Institution of Oceanography When earthquakes happen, they not only cause ground shaking, but they also cause changes in the shape of the surface of the Earth. We can measure these changes in a number of ways, but one way to see the changes in broad scope, in high spatial resolution, is to look from above, using satellite-based Synthetic Aperture Radar (SAR) data. What we see here is two Sentinel-1 mission satellite radar images that were taken before and after the July 2019 Ridgecrest, CA earthquake sequence that have been interfered, or differenced, to highlight how the surface has changed between the two collection dates. Each rainbow of color, varying from black to pale yellow indicates 28 mm of surface change. The bullseye at the center of the image indicates the locations of the M6.4 and M7.1 earthquakes, and the higher number of “rainbows”, the more surface change that occurred. In white, we plot the locations of surface ruptures, where the localized earthquake energy caused permanent breaks and faults to open at ground level. These kinds of images help us understand the extent of earthquake deformation in a regional context, and allow us to better quantify future earthquake hazards for the area.

【说明】基于卫星的雷达成像技术可捕捉加利福尼亚州东部由地震活动引发的地表形变。参与者类别：博士后；所属部门：斯克里普斯海洋研究所（Scripps Institution of Oceanography）。
地震发生时，不仅会引发地面震动，还会改变地球表层形态。我们可通过多种手段监测此类形变，而基于卫星的合成孔径雷达（Synthetic Aperture Radar, SAR）数据，则是实现大范围、高空间分辨率地表形变观测的可靠途径之一。
本次展示的为两张Sentinel-1任务卫星采集的雷达影像，分别获取于2019年7月美国加利福尼亚州里奇克莱斯特（Ridgecrest）地震序列发生的前后时段；通过对两幅影像开展干涉或差分处理，可清晰凸显两次成像时段间的地表形变特征。
每条由黑色至浅黄色渐变的彩色条带，均对应28毫米的地表形变量。图像中央的靶区标记了M6.4级与M7.1级地震的震中位置，“彩条”分布越密集，则代表该区域的地表形变幅度越大。
图像以白色线条标注了地表破裂带的分布位置——这类区域因局部地震能量作用，发生了永久性地表断裂与断层错动。
此类影像有助于我们从区域尺度明晰地震形变的波及范围，同时可为该区域未来地震灾害的量化评估提供关键支撑。