Shallow‐Focus Repeating Earthquakes in the Tonga–Kermadec–Vanuatu Subduction Zones
Shallow‐Focus Repeating Earthquakes in the Tonga–Kermadec–Vanuatu Subduction Zones
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DOI：
10.1785/0120120123
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发表时间：
2013-02
影响因子：
3
通讯作者：
Wen Yu
中科院分区：
文献类型：
--
作者：
Wen Yu
本文通过对远震记录的波形进行互相关，研究了汤加-克马德克-瓦努阿图俯冲带沿着的中度浅源重复地震。共鉴定出23个簇和31个双峰，平均互相关系数>0.8。主事件算法用于确定精确的相对位置。然后，我估计并叠加这些事件对之间的源区域。这种分析表明，这些相关对大多数是重复地震，具有相似的地震矩（M）和完全重叠的震源区。大多数中等重复地震是准周期性的，复发间隔（Tr）为年的数量级，并发生在板块界面。重复地震被用来研究断层滑动率的时空变化（！[图][1]）和板间耦合。除了空间的变化！[图形][2]，时间加速！[图][3]与瓦努阿图地区的大型板间地震有关。除汤加弧南纬15°-19°的北方部分外，大部分研究区板间耦合较弱。汤加北方板间区域的强耦合似乎与弧后伸展活跃区域的解耦不一致。重复地震也被用来检查M和T r来自圣安德烈亚斯断层（SAF）之间的标度关系。从SAF中导出的Tr − M标度关系可以充分解释Kermadec、瓦努阿图和汤加板间区域的归一化Tr，在这些区域，Tr是解耦的，这表明收敛速率是重复地震序列中对复发间隔的主要影响。[1]：/embed/inline-graphic-1.gif [2]：/embed/inline-graphic-2.gif [3]：/embed/inline-graphic-3.gif
This paper examines moderate shallow‐focus repeating earthquakes along the Tonga–Kermadec–Vanuatu subduction zones by cross‐correlating teleseismically recorded waveforms. A total of 23 clusters and 31 doublets are identified with an average cross‐correlation coefficient of >0.8. A master‐event algorithm is used to determine the precise relative locations. I then estimate and superpose the source areas among these event pairs. This analysis reveals that most of these correlated pairs are repeating earthquakes, which have similar seismic moments ( M ) and completely overlapping source areas. Most of the moderate repeating earthquakes were quasi‐periodic with a recurrence interval ( T r) on the order of years, and occurred at the plate interface. The repeating earthquakes are used to study spatial–temporal variations in fault‐slip rate (![Graphic][1] ) and interplate coupling. Apart from spatial variations in ![Graphic][2] , a temporal acceleration in ![Graphic][3] is observed, associated with large interplate earthquakes in the Vanuatu region. Interplate coupling is weak for most of the study areas, except the northern section 15°–19° S of the Tonga arc. Strong coupling in the northern Tonga interplate region appears to be at odds with the decoupling expected of a region associated with active back‐arc extension. Repeating earthquakes are also used to examine the scaling relationship between M and T r derived from the San Andreas fault (SAF). The T r− M scaling relationship derived from the SAF can adequately account for the normalized T r for the Kermadec, Vanuatu, and Tonga interplate regions where it is decoupled, suggesting that the convergence rate is the predominant influence on the recurrence interval in a repeating earthquake sequence. [1]: /embed/inline-graphic-1.gif [2]: /embed/inline-graphic-2.gif [3]: /embed/inline-graphic-3.gif