We conduct a high-resolution teleseismic receiver function investigation of the subducting plate interface within the Alaskan forearc beneath Kodiak Island using data collected as part of the Alaska Amphibious Community Seismic Experiment in 2019. The Kodiak node array consisted of 398 nodal geophones deployed at ∼200–300 m spacing on northeastern Kodiak Island within the southern asperity of the 1964 Mw9.2 Great Alaska earthquake. Receiver function images at frequencies of 1.2 and 2.4 Hz show a coherent, slightly dipping velocity increase at ∼30–40 km depth consistent with the expected slab Moho. In contrast to studies within the northern asperity of the 1964 rupture, we find no evidence for a prominent low-velocity layer above the slab Moho thick enough to be resolved by upgoing P-to-S conversions. These results support evidence from seismicity and geodetic strain suggesting that the 1964 rupture connected northern (Kenai) and southern (Kodiak) asperities with different plate interface properties.

中文翻译：

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南部 MW9.2 1964 年阿拉斯加大地震中的俯冲带界面结构：空间密集节点阵列中接收器功能的约束

我们使用 2019 年作为阿拉斯加两栖社区地震实验的一部分收集的数据，对科迪亚克岛下方阿拉斯加前弧内的俯冲板界面进行高分辨率远震接收器功能调查。科迪亚克节点阵列由 398 个节点地震检波器组成，部署在 ~200在 1964 年 Mw9.2 大阿拉斯加地震的南部崎岖地带，科迪亚克岛东北部的间距为 –300 米。频率为 1.2 和 2.4 Hz 的接收器函数图像显示，在约 30-40 km 深度处有一个连贯的、略微倾斜的速度增加，与预期的板片莫霍面一致。与 1964 年破裂的北部粗糙区域内的研究相比，我们没有发现任何证据表明 Moho 板片上方有一个显着的低速层，其厚度足以通过向上的 P-to-S 转换来解决。