The 1995 Kobe earthquake: Seismic image of the source zone and its implications for the rupture nucleation
The 1995 Kobe earthquake: Seismic image of the source zone and its implications for the rupture nucleation
复制标题
1995 年神户地震：震源区的地震图像及其对破裂成核的影响
DOI：
10.1029/97jb03670
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发表时间：
1998
影响因子：
--
通讯作者：
H. Negishi
中科院分区：
文献类型：
--
作者：
Dapeng Zhao;H. Negishi
为了了解什么可能引发了1995年日本科比地震，以及如何破裂后开始进行，我们确定了高分辨率的三维（3-D）P和S波速度和泊松比结构在科比震中区和重新定位余震与获得的3-D速度模型。我们使用了科比主震后建立的永久地震台网和便携式台站记录的3634次科比余震和当地微震的64，337 P波和49，200 S波高质量到达时间。在余震区发现了高达6%的显著速度变化。我们发现，余震活动高的地区通常与低泊松比相联系，这可能是断裂带的强有力的部分，容易产生余震。科比主震震源位于一个具有低P、S波速度和高泊松比特征的特殊区域。这种异常存在于16至21公里的深度范围内，横向延伸15至20公里。这种异常可能是由于充满流体的断裂岩石基质导致了科比地震的发生。在科比地震区进行的水文、地球化学、地震和地球物理调查的许多证据支持了我们的解释。
In order to understand what may have triggered the 1995 Kobe, Japan, earthquake and how the rupture proceeded after initiation, we determined high-resolution three-dimensional (3-D) P and S wave velocity and Poisson's ratio structures in the Kobe epicentral area and relocated the aftershocks with the obtained 3-D velocity model. We used 64,337 P and 49,200 S wave high-quality arrival times from 3634 Kobe aftershocks and local microearthquakes recorded by both permanent seismic networks and portable stations that were set up following the Kobe mainshock. Significant velocity variations of up to 6% are revealed in the aftershock area. We found that areas with high aftershock activity are generally associated with low Poisson's ratio, which may be the strong and competent parts of the fault zone and were apt to generate aftershocks. The Kobe mainshock hypocenter is located in a distinctive zone characterized by low P and S wave velocities and a high Poisson's ratio. This anomaly exists in the depth range of 16 to 21 km and extends 15 to 20 km laterally. This anomaly may be due to a fluid-filled, fractured rock matrix that contributed to the initiation of the Kobe earthquake. Our interpretation has been supported by many pieces of evidence from hydrological, geochemical, seismological, and geophysical investigations conducted at the Kobe earthquake region.