Nazca subduction beneath South America is one of our best modern examples of long‐lived ocean‐continent subduction on the planet, serving as a foundation for our understanding of subduction processes. Within that framework, persistent heterogeneities at a range of scales in both the South America and Nazca plates is difficult to reconcile without detailed knowledge of the subducted Nazca slab structure. Here we use teleseismic travel time residuals from >1,000 broadband and short‐period seismic stations across South America in a single tomographic inversion to produce the highest‐resolution contiguous P wave tomography model of the subducting slab and surrounding mantle beneath South America to date. Our model reveals a continuous trench‐parallel fast seismic velocity anomaly across the majority of South America that is consistent with the subducting Nazca slab. The imaged anomaly indicates a number of robust features of the subducted slab, including variable slab dip, extensive lower mantle penetration, slab stagnation in the lower mantle, and variable slab amplitude, that are incorporated into a new, comprehensive model of the geometry of the Nazca slab surface to ~1,100 km depth. Lower mantle slab penetration along the entire margin suggests that lower mantle slab anchoring is insufficient to explain along strike upper plate variability while slab stagnation in the lower mantle indicates that the 1,000 km discontinuity is dominant beneath South America.

中文翻译：

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从大陆规模远震P波层析成像推导的纳斯卡板俯冲到下地幔的详细结构

南美下方的纳斯卡俯冲是我们在地球上长期存在的海洋大陆俯冲的最好的现代例子之一，为我们了解俯冲过程奠定了基础。在此框架内，如果不详细了解俯冲的纳斯卡板状结构，就很难调和南美和纳斯卡板块在一定范围内持续存在的异质性。在这里，我们在一次层析成像反演中使用南美各地超过1,000个宽带和短周期地震台站的远震传播时间残差，以产生最高分辨率的连续P迄今为止，南美下方俯冲板和周围地幔的波层析成像模型。我们的模型揭示了南美洲大部分地区的连续平行于平行沟槽的快速地震速度异常，这与俯冲的纳斯卡平板一致。成像的异常表明俯冲板块具有许多强大的特征，包括可变的板块倾角，广泛的下部地幔穿透，下部地幔中的板块停滞以及可变的板块振幅，这些特征已合并到新的，全面的地壳几何模型中纳斯卡板的表面深度约为1100公里。下地幔板沿整个边缘的穿透表明，下地幔板的锚固不足以解释沿上板的变化，而下地幔板的停滞表明，1，