The 2019 Ridgecrest earthquake sequence culminated in the largest seismic event in California since the 1999Mw 7.1 Hector Mine earthquake. Here, we combine geodetic and seismic data to study the rupture process of both the 4 JulyMw 6.4 foreshock and the 6 JulyMw 7.1 mainshock. The results show that the Mw 6.4 foreshock rupture started on a northwest-striking right-lateral fault, and then continued on a southwest-striking fault with mainly left-lateral slip. Although most moment release during the Mw 6.4 foreshock was along the southweststriking fault, slip on the northwest-striking fault seems to have played amore important role in triggering theMw 7.1mainshock that happened ∼34 hr later. Rupture of theMw 7.1 mainshock was characterized by dominantly right-lateral slip on a series of overall northweststriking fault strands, including the one that had already been activated during the nucleation of the Mw 6.4 foreshock. The maximum slip of the 2019 Ridgecrest earthquake was ∼5 m, located at a depth range of 3–8 km near theMw 7.1 epicenter, corresponding to a shallow slip deficit of ∼20%–30%. Both the foreshock and mainshock had a relatively low-rupture velocity of ∼2 km= s, which is possibly related to the geometric complexity and immaturity of the eastern California shear zone faults. The 2019 Ridgecrest earthquake produced significant stress perturbations on nearby fault networks, especially along the Garlock fault segment immediately southwest of the 2019 Ridgecrest rupture, in which the coulomb stress increase was up to ∼ 0:5 MPa. Despite the good coverage of both geodetic and seismic observations, published coseismic slip models of the 2019 Ridgecrest earthquake sequence show large variations,which highlight the uncertainty of routinely performed earthquake rupture inversions and their interpretation for underlying rupture processes.

中文翻译：

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受地震和大地测量数据约束的 2019 年加利福尼亚州里奇克莱斯特 Mw 6.4 前震和 Mw 7.1 地震的破裂过程

2019 年 Ridgecrest 地震序列最终导致加利福尼亚自 1999 年 Mw 7.1 Hector Mine 地震以来最大的地震事件。在这里，我们结合大地测量和地震数据来研究 4 JulyMw 6.4 前震和 6 JulyMw 7.1 主震的破裂过程。结果表明，Mw 6.4 前震破裂开始于一条西北走向的右旋断层，然后在一条以左旋滑动为主的西南走向断层上延续。尽管 Mw 6.4 前震期间的大部分矩释放是沿着西南走向的断层，但西北走向的断层上的滑动似乎在触发约 34 小时后发生的 Mw 7.1 主震方面发挥了更重要的作用。Mw 7.1 主震破裂的特点是在一系列整体向西北走向的断层链上以向右滑动为主，包括在 Mw 6.4 前震成核过程中已经被激活的那个。2019 年 Ridgecrest 地震的最大滑动量为~5 m，位于 Mw 7.1 震中附近 3-8 公里的深度范围内，对应于~20%~30% 的浅层滑动赤字。前震和主震的破裂速度都相对较低，约为 2 km= s，这可能与加利福尼亚东部剪切带断层的几何复杂性和不成熟性有关。2019 年 Ridgecrest 地震对附近的断层网络产生了显着的应力扰动，尤其是沿着 2019 年 Ridgecrest 破裂西南方向的 Garlock 断层段，其中库仑应力增加了约 0:5 MPa。尽管大地测量和地震观测都有很好的覆盖范围，