Foreshocks and Mainshock Nucleation of the 1999 Mw 7.1 Hector Mine, California, Earthquake
Foreshocks and Mainshock Nucleation of the 1999 Mw 7.1 Hector Mine, California, Earthquake
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DOI：
10.1029/2018jb016383
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发表时间：
2019-02
期刊：
影响因子：
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通讯作者：
C. Yoon;N. Yoshimitsu;W. Ellsworth;G. Beroza
中科院分区：
文献类型：
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作者：
C. Yoon;N. Yoshimitsu;W. Ellsworth;G. Beroza
前震提供了有关即将发生的大地震的成核过程的宝贵信息。我们应用高分辨率相似波形技术进行地震检测、定位和震源参数估计，以了解前震序列的时空演化及其与主震震源的关系。 1999 年加利福尼亚州 Mw 7.1 Hector 矿地震在主震前 20 小时内发生了 50 次前震 (−0.4 ≤ M ≤ 3.7)。前震活动并未加速导致主震。随着时间的推移，它们的位置向北移动，沿断层面破裂相邻区域，几乎没有重叠，但仍保持在小于 2 平方公里的紧凑体积内。主震发生在先前前震局部增加剪应力的位置。这些观察结果与触发的应力传递级联一致，其中先前的前震使相邻断层块破裂，成为额外的前震，并最终形成主震。
Foreshocks provide valuable information on the nucleation process of an upcoming large earthquake. We applied high‐resolution similar‐waveform techniques for earthquake detection, location, and source parameter estimation to understand the space‐time evolution of a foreshock sequence and its relationship to the mainshock hypocenter. The 1999 Mw 7.1 Hector Mine, California, earthquake was preceded by 50 foreshocks (−0.4 ≤ M ≤ 3.7) during the 20 hr before the mainshock. Foreshock activity did not accelerate leading up to the mainshock. Their locations moved north with time, rupturing adjacent areas along the fault plane with little overlap, but remained within a compact <2 km3 volume. The mainshock initiated at a location where previous foreshocks had locally increased the shear stress. These observations are consistent with a triggered cascade of stress transfer, where previous foreshocks load adjacent fault patches to rupture as additional foreshocks, and eventually the mainshock.