Microseismicity Indicates Atypical Small‐Scale Plate Rotation at the Quebrada Transform Fault System, East Pacific Rise
Microseismicity Indicates Atypical Small‐Scale Plate Rotation at the Quebrada Transform Fault System, East Pacific Rise
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DOI：
10.1029/2021gl097000
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发表时间：
2022-01
影响因子：
5.2
通讯作者：
J. Gong;W. Fan;R. Parnell‐Turner
中科院分区：
文献类型：
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作者：
J. Gong;W. Fan;R. Parnell‐Turner
密集分布的多股洋脊转换断层（RTF）适应了沿着快速扩张的洋中脊的相对运动。然而，RTF和板块扩张动力学之间的关系知之甚少。克夫拉达系统是东太平洋海隆最独特的RTF系统之一，由四个转换断层组成，由三个短的转换内扩展中心（ITSC）连接。我们使用了7个月的海底地震仪数据来研究Quebrada系统，并发现大量的地震不均匀地分布在三个活动断层之间。我们在ITSC转换断层交叉点的内角处确定了两个深而弥散的地震活动云，以及一个地震活动断裂带。这些观测结果表明了一个复杂的区域板块运动模式，包括克布拉达系统内可能的非均匀旋转。多股RTF的演化可能是由于强烈的三维局部热效应和流体效应，而RTF也可能调节区域构造，形成复杂的反馈系统。
Closely spaced, multi‐strand ridge transform faults (RTFs) accommodate relative motions along fast spreading mid‐ocean ridges. However, the relations between RTFs and plate spreading dynamics are poorly understood. The Quebrada system is one of the most unique RTF systems at the East Pacific Rise, consisting of four transform faults connected by three short intra‐transform spreading centers (ITSCs). We use seven‐months of ocean bottom seismograph data to study the Quebrada system, and find abundant earthquakes unevenly distributed among three active faults. We identify two deep, diffuse seismicity clouds at the inside corners of the ITSC‐transform fault intersections, and one seismically active fracture zone. The observations suggest a complex regional plate‐motion pattern, including possible heterogeneous rotations within the Quebrada system. Evolution of multi‐strand RTFs may have resulted from a strong three‐dimensional local thermal and fluid effects, while the RTFs may have also regulated regional tectonics, forming an intricate feedback system.