The rupture process of the 2018 M_w 7.9 offshore Kodiak (Alaska) earthquake is still in hot dispute because of a lack of offshore observations, thus causing difficulties for understanding seismogenic tectonics and tsunami hazards. In this study, teleseismic body waves, high‐rate GPS, seismic waves preceding tsunami waves, static GPS, and tsunami data are jointly used to resolve the faulting geometry and coseismic slip distribution of the offshore Kodiak earthquake. Tests of a series of finite fault rupture models illustrate that an optimal five‐fault model can reconcile all available data sets well. The results reveal that the asperity on each fault segment is located near the hypocenter, with peak slip of ~7.8 m. The aftershock loci appear to be complementary to the mainshock slips, demonstrating the velocity‐strengthening regions that predominantly slip aseismically. Based on a tectonic stress field analysis, we propose that the 2018 Kodiak earthquake is attributed to a combination of enhanced tensional stress following the 1964 M_w 9.2 Alaska earthquake and compressional stress produced by the collision of the Yakutat terrane with North America.

中文翻译：

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2018年Mw 7.9海上地震，阿拉斯加科迪亚克地震：一次不寻常的外部上升滑动地震

2018 M _W的破裂过程7.9由于缺乏离岸观测资料，近海科迪亚克（阿拉斯加）地震仍是热门话题，因此难以理解致震构造和海啸危害。在这项研究中，远震体波，高速率GPS，海啸之前的地震波，静态GPS和海啸数据共同用于解决科迪亚克海上地震的断层几何形状和同震滑动分布。对一系列有限故障模型的测试表明，最佳的五故障模型可以很好地协调所有可用数据集。结果表明，每个断层段的凹凸不平都位于震源附近，峰值滑动约为7.8 m。余震轨迹似乎与主震滑动是互补的，表明主要是抗震滑动的速度加强区域。中号_W¯¯ 9.2阿拉斯加地震和由亚库塔特地块与北美的碰撞时产生压应力。