On October 9, 2014, a Mw 7.1–6.7 seismic doublet occurred at the Juan Fernández microplate, close to the triple junction with Pacific and Nazca plates. The Mw 7.1 earthquake is the largest earthquake ever to have been recorded in the region. Its thrust focal mechanism is also unusual for the region, although the northern part of the microplate is expected to undergo compression. The region is remote and seismological data is limited to a seismic station at ~600 km distance on Easter Island and teleseismic observations for the largest events. We use a combination of advanced seismological techniques to overcome the lack of local data and resolve earthquake source parameters for the doublet and its aftershock sequence, being able to reconstruct the chronology of the sequence and the geometry of affected fault segments. Our results depict a complex seismic sequence characterized by the interplay of thrust and strike-slip earthquakes along different structures, including a second, reversed strike slip-thrust seismic doublet in November 2014. Seismicity occurred within the microplate and only in the late part of the sequence migrated northward, towards the microplate boundary. The first largest doublet, whose rupture kinematic is well explained by stress changes imparted by the first subevent on the second one, may have activated unmapped E-W and NE-SW faults or an internal curved pseudofault, attributed to the long-term rotation of the microplate. Few large, thrust earthquakes are observed within the sequence, taking place in the vicinity of mapped compressional ridges. We suggest that compressional stresses in the northern part of the microplate and at its boundary are partially accommodated aseismically. However, the occasional occurrence of large, impulsive thrust earthquakes, with a considerable tsunamigenic potential, poses a relevant hazard for islands in the South Pacific region.

2014年10月9日，胡安·费尔南德斯（JuanFernández）微孔板发生了7.1–6.7 Mw地震双峰，靠近与太平洋和纳斯卡板块的三重交界处。7.1级Mw地震是该地区有记录以来最大的地震。尽管预计微孔板的北部会受到压缩，但它的推力聚焦机制在该地区也不常见。该地区是偏远地区，地震数据仅限于复活节岛上约600 km距离的地震台和最大事件的远震观测。我们结合先进的地震技术，克服了当地数据不足的问题，并解析了双重峰及其余震序列的震源参数，能够重建序列的时间顺序和受影响断层段的几何形状。我们的结果描绘了一个复杂的地震序列，其特征是沿着不同结构的推力和走滑地震相互作用，包括2014年11月的第二次反向走滑推力地震双峰。地震发生在微孔板内，仅发生在板块的后期。序列向北迁移，朝向微孔板边界。第一个最大的双峰可能通过未映射激活，其破裂运动学可以由第二个第一个子事件施加的应力变化很好地解释。E -W和NE-SW故障或内部弯曲的伪故障，归因于微孔板的长期旋转。在该序列中几乎没有观察到大的逆冲地震，发生在测绘的压缩脊附近。我们建议在微孔板的北部及其边界处的抗压应力被部分地抗震地容纳。然而，偶发的大的冲激地震具有巨大的海啸潜在性，对南太平洋区域的岛屿构成了相关的危害。