We report a new model of radially anisotropic crustal and upper mantle structure of the western United States (WUS324) obtained from full waveform inversion of earthquake data. We ran three multiscale inversion stages beyond model WUS256 (Rodgers et al., 2022, https://doi.org/10.1029/2022jb024549) allowing them to approach convergence to fit a larger data set to a shorter minimum period of 16 s. WUS324 is based on 324 total iterations from its starting model, significantly more (16 times) than previous studies. Waveform misfit reductions are 66%–70% for both the inversion data and an independent validation data set providing confidence in the predictive power of the model. WUS324 provides much better fits and reveals shear wavespeed, v_S, structure of this large region with more detail than previous waveform tomography models. We show representative images demonstrating the resolution of diverse seismic structure across this highly heterogeneous region including oceanic lithosphere, subducting slabs and continental magmatism.

中文翻译：

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WUS324： 接近收敛的多尺度全波形反演在对美国西部地震结构进行成像时改善了波形拟合


我们报道了从地震数据的全波形反演中获得的美国西部径向各向异性地壳和上地幔结构的新模型 （WUS324）。我们在模型 WUS256 之外运行了三个多尺度反转阶段（Rodgers et al.， 2022， https://doi.org/10.1029/2022jb024549），使它们能够接近收敛，以将更大的数据集拟合到更短的最小周期 16 秒。WUS324 基于其起始模型的总 324 次迭代，明显多（16 倍）于以前的研究。对于反演数据和独立的验证数据集，波形失配减少为 66%–70%，为模型的预测能力提供了信心。WUS324 提供了更好的拟合，并揭示了这个大区域的剪切波速度 v_S 结构，比以前的波形层析成像模型更详细。我们展示了代表性图像，展示了这个高度异质区域不同地震结构的分辨率，包括海洋岩石圈、俯冲板块和大陆岩浆作用。