Two-Staged Rupture of the 19 October 2020 Mw 7.6 Strike-Slip Earthquake Illuminated the Boundary of Coupling Variation in the Shumagin Islands, Alaska
Two-Staged Rupture of the 19 October 2020 Mw 7.6 Strike-Slip Earthquake Illuminated the Boundary of Coupling Variation in the Shumagin Islands, Alaska
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2020 年 10 月 19 日 Mw 7.6 走滑地震的两阶段破裂揭示了阿拉斯加舒马金群岛耦合变化的边界
DOI：
10.1785/0220220203
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发表时间：
2022-10
影响因子：
3.3
通讯作者：
Yuyang Peng
中科院分区：
文献类型：
--
作者：
Zhifan Wan;Dun Wang;Junfeng Zhang;Qi Li;Lianfeng Zhao;Yifang Cheng;Jim Mori;Fang Chen;Yuyang Peng
抽象。2020年10月19日，阿拉斯加州舒马金群岛发生Mw 7. 6地震，这是在地震观测丰富的浅俯冲板块中发生的最大走滑地震。在这里，我们重新定位的地震序列，实施反投影分析，有限断层反演调查的震源过程的主震，并计算主震震源机制分别使用P波和W-相位反转的极性。结果表明，主震的断层活动可分为两段，初始破裂沿着较陡的破裂面（走向15°，倾角81°），沿沿着较浅的破裂面（走向344°，倾角48°）向东南扩展。主震断层的推断走向与震源区先存构造的方向相似，可能表明2020年Mw7.6地震是沿下行板块中先存板块组构沿着破裂的。这些组构位于板块耦合显著变化的边界处，表明俯冲板块内的这些结构可能会影响板间耦合，或者是俯冲带中板间耦合变化的结果。
Abstract. On 19 October 2020, an Mw7.6 earthquake occurred within the Shumagin Islands, Alaska, which is the largest strike-slip earthquake occurred in the shallow subducted plates with abundant seismic observations. Here, we relocated the earthquake sequence, implemented back-projection analyses, and finite-fault inversion to investigate the source processes of the mainshock, and calculated mainshock focal mechanisms using the polarities of P waves and W-phase inversion, respectively. Our results show that the faulting of the mainshock can be divided into two segments with the initial rupture along a steep plane (strike = 15°, dip = 81°) and propagation southeastward along a more shallowly dipping plane (strike = 344°, dip = 48°). The inferred strikes of the mainshock faults are similar to the orientations of preexisting structures in the source region, likely indicating that the 2020 Mw7.6 earthquake ruptured along the preexisting plate fabric in the downgoing plate. The fabrics are located at the boundary with significant variations of the plate coupling, indicating that these structures within the subducting plate may affect the interplate coupling or as a result of the varying interplate coupling in subduction zones.
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影响因子：
5.3
作者：
T. Tsuji;S. Minato;R. Kamei;T. Tsuru;G. Kimura
通讯作者：
T. Tsuji;S. Minato;R. Kamei;T. Tsuru;G. Kimura
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影响因子：
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作者：
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通讯作者：
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