Spatial changes of inter‐plate coupling inferred from sequences of small repeating earthquakes in Japan
Spatial changes of inter‐plate coupling inferred from sequences of small repeating earthquakes in Japan
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从日本小重复地震序列推断板间耦合的空间变化
DOI：
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发表时间：
2010
期刊：
影响因子：
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通讯作者：
T. Igarashi
中科院分区：
文献类型：
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作者：
T. Igarashi
我们提取了小重复地震序列，以澄清日本群岛大面积俯冲板块的板间耦合。因此，在从琉球海沟俯冲的菲律宾海板块和从千岛-日本海沟俯冲的太平洋板块上检测到许多序列。从序列中估计的平均滑移率和标准差显示了板间耦合的实质性空间变化。滑动速率的大偏差对应于幕式滑动的发生，例如大地震后的后遗滑动。接近板块相对运动的恒定滑移率表明弱耦合区域。滑动赤字和稀疏分布的重复组建议锁定的地区。在南海海槽，过渡带的深源低频地震和板块内的突发型重复序列并不位于慢滑动速率组的下倾方向。这表明板间耦合的时空特征影响了这些地震事件。
We extract sequences of small repeating earthquakes to clarify inter‐plate coupling of subducting plates over a large area of the Japanese Islands. As a result, many sequences are detected at the Philippine Sea plate subducting from the Ryukyu trench and Pacific plate subducting from the Kuril‐Japan trench. The average slip‐rates and standard deviations estimated from the sequences show substantial spatial changes of inter‐plate coupling. The large deviations of slip‐rates correspond to the occurrence of episodic slips such as after‐slips following large earthquakes. Constant slip‐rates approaching the relative plate motion indicate weak coupling areas. Slip deficits and sparse distributions of repeating groups suggest locked areas. In the Nankai trough, deep low‐frequency earthquakes in the transition zone and burst‐type repeating sequences within plates have not been located in the downdip direction of groups with slow slip‐rates. This suggests that the space‐time characteristics of inter‐plate coupling affected these seismic events.