Time‐Lapse Imaging of Coseismic Ruptures for the 2019 Ridgecrest Earthquakes Using Multiazimuth Backprojection With Regional Seismic Data and a 3‐D Crustal Velocity Model
Time‐Lapse Imaging of Coseismic Ruptures for the 2019 Ridgecrest Earthquakes Using Multiazimuth Backprojection With Regional Seismic Data and a 3‐D Crustal Velocity Model
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DOI：
10.1029/2020gl087181
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发表时间：
2020-05
影响因子：
5.2
通讯作者：
Jidong Yang;Hejun Zhu;D. Lumley
中科院分区：
文献类型：
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作者：
Jidong Yang;Hejun Zhu;D. Lumley
利用区域地震数据和三维地壳速度模型，我们发展了一种新的多方位反投影方法，并将其应用于2019年Ridgecest地震的时移同震破裂图像。Mw6.4级前震和Mw7.1级主震的时间积分图像与余震分布所描绘的断层几何形状一致。不同时间的反投影图像显示了这两个事件的详细破裂过程。例如，Mw6.4级前震在震中附近初始，然后破裂沿一条西北向断裂传播，平均速度为1.0公里/S，最后跳跃到一条西南向断裂，传播速度约为1.5公里/S；而Mw7.1级主震在震中附近初始，然后向西北方向传播，到达COSO火山场后，平均速度为1.4公里/S，后来转向东南方向，沿主断裂带传播，过程复杂，速度约0.6公里/S。
Using regional seismic data and a 3‐D crustal velocity model, we develop a novel multiazimuth backprojection approach and apply it to image time‐lapse coseismic ruptures for the 2019 Ridgecrest earthquakes. The time‐integrated images for the Mw6.4 foreshock and Mw7.1 mainshock agree with the fault geometry delineated by the aftershock distributions. Backprojection images at different times illustrate the detailed rupture processes for these two events. For instance, the Mw6.4 foreshock initialized close to the hypocenter, then the rupture propagated along a northwest trending fault with an average velocity of 1.0 km/s, and finally jumped to a southwest trending fault and propagated about 20 km with a velocity about 1.5 km/s. In contrast, the Mw7.1 mainshock initialized near the hypocenter, then propagated to the northwest upon reaching the Coso volcanic field with an average velocity of 1.4 km/s, and later turned to the southeast and propagated along the main fault zone with a complex bilateral process and a velocity about 0.6 km/s.