近日，美国地质灾害科学中心David R. Shelly团队报道了低频地震追踪被捕获的板块碎片的运动。相关论文于2026年1月15日发表在《科学》杂志上。

精确的构造模型对于评估地震危险性及断层相互作用至关重要。然而，在圣安德烈亚斯断裂带与卡斯卡迪亚俯冲带交汇的复杂门多西诺三联点区域，其板块构造格局仍不明确。

研究组分析了在俯冲的戈尔达板块南缘附近新近发现的构造震颤与低频地震（LFEs）活动带的断层滑动特征。基于潮汐敏感性分析与P波初动方向，研究表明这些低频地震由倾斜的走滑运动产生。这表明一片曾属法拉隆板块的碎片（现已被太平洋板块捕获）正在北美大陆最西部下方向北移动。这一构造格局有效延伸了板块界面断层的范围，对当前关于板片窗形成的通行解释提出了挑战，并可能在该区域产生尚未被充分认识的地震风险。

附：英文原文

Title: Low-frequency earthquakes track the motion of a captured slab fragment

Author: David R. Shelly, Amanda M. Thomas, Kathryn Z. Materna, Robert J. Skoumal

Issue&Volume: 2026-01-15

Abstract: Accurate tectonic models are essential for assessing seismic hazard and fault interactions. However, the plate configuration at the complex Mendocino triple junction, where the San Andreas Fault and the Cascadia subduction zone meet, remains uncertain. We analyzed fault slip associated with a recently identified zone of tectonic tremor and low-frequency earthquakes (LFEs) near the southern edge of the subducting Gorda slab. Based on tidal sensitivity and P-wave first motions, we show that the LFEs are generated by dipping, strike-slip motion. This suggests that a former Farallon slab fragment, now captured by the Pacific plate, is translating northward beneath westernmost North America. This geometry effectively extends the slab interface fault, challenging prevailing interpretations of slab window formation and creating a potential unaccounted earthquake hazard in this region.

DOI: aeb2407

Source: https://www.science.org/doi/10.1126/science.aeb2407