Aseismic Transform Fault Slip at the Mendocino Triple Junction From Characteristically Repeating Earthquakes
Aseismic Transform Fault Slip at the Mendocino Triple Junction From Characteristically Repeating Earthquakes
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DOI：
10.1002/2017gl075899
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发表时间：
2018-01
影响因子：
5.2
通讯作者：
K. Materna;T. Taira;R. Bürgmann
中科院分区：
文献类型：
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作者：
K. Materna;T. Taira;R. Bürgmann
Mendocino三重交界处（MTJ）位于圣安德烈亚斯断层系统的北端，是一个活跃变形的板块边界区域，对大多数海上断层表面的地震耦合估计约束很差。具有特征的重复地震提供了MTJ地震蠕变的空间和时间描述，包括海洋转换门多西诺断裂带（MFZ），因为它俯冲到北美之下。使用2008年至2017年的地震数据集，我们发现MFZ的最东段在此期间以约65%的长期滑动率显示蠕变。我们还发现，在太平洋板块和北美增生楔之间较浅的走滑界面上，以及在一个容纳戈尔达板块内部变形的断层上，蠕变速度较慢。在2015年附近发生5.7级地震后，我们观察到近岸MFZ的地震滑动可能从2015年持续到至少2017年初。
The Mendocino Triple Junction (MTJ), at the northern terminus of the San Andreas Fault system, is an actively deforming plate boundary region with poorly constrained estimates of seismic coupling on most offshore fault surfaces. Characteristically repeating earthquakes provide spatial and temporal descriptions of aseismic creep at the MTJ, including on the oceanic transform Mendocino Fault Zone (MFZ) as it subducts beneath North America. Using a dataset of earthquakes from 2008 to 2017, we find that the easternmost segment of the MFZ displays creep during this period at about 65% of the long‐term slip rate. We also find creep at slower rates on the shallower strike‐slip interface between the Pacific plate and the North American accretionary wedge, as well as on a fault that accommodates Gorda subplate internal deformation. After a nearby M5.7 earthquake in 2015, we observe a possible decrease in aseismic slip on the near‐shore MFZ that lasts from 2015 to at least early 2017.