Seismic full‐waveform inversion of the crust‐mantle structure beneath China and adjacent regions
Seismic full‐waveform inversion of the crust‐mantle structure beneath China and adjacent regions
复制标题
中国及邻区地壳幔结构地震全波形反演
DOI：
10.1029/2022jb024957
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发表时间：
2022
期刊：
影响因子：
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通讯作者：
Tingting Liu
中科院分区：
文献类型：
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作者：
Jincheng Ma;Hans-Peter Bunge;Solvi Thrastarson;Andreas Fichtner;Dirk‐Philip van Herwaarden;You Tian;Sung-Joon Chang;Tingting Liu
介绍了中国及邻区第一代全波层析成像模型（SinoScope 1.0）。利用2，427个台站记录的410次地震的三分量地震图，对70-120 s、50-120 s和30-120 s三个连续加宽的周期带进行基于梯度的迭代反演。合成地震图是使用GPU加速的三维滞弹性模型中地震波传播的谱元模拟计算的，而Fréchet导数是基于检查点算法辅助的伴随状态方法计算的。SinoScope 1.0采用各向同性P波（VP）、水平和垂直极化S波速度（VSH和VSV）以及质量密度（ρ）进行描述，这些参数均独立地受到相同数据集以及随机L-BFGS拟牛顿优化方案的约束。它系统地减少了观测到的和合成的全长地震图之间的差异。通过对输入随机参数扰动的修正，我们进行了详细的分辨率分析，结果表明，在覆盖良好的区域内，分辨率长度可以接近半传播波长。SinoScope 1.0揭示了岩石圈中强烈的横向非均匀性，并且特征与地质观测结果有很好的相关性，如沉积盆地、全新世火山、青藏高原、菲律宾海板块和各种构造单元。软流圈位于东亚和东南亚岩石圈之下，以俯冲沟和俯冲块体为界。此外，我们观察到一个增强的图像，著名的板沿着强烈弯曲的俯冲带，这并不存在于初始模型。
We present the first‐generation full‐waveform tomographic model (SinoScope 1.0) for the crust‐mantle structure beneath China and adjacent regions. The three‐component seismograms from 410 earthquakes recorded at 2,427 stations are employed in iterative gradient‐based inversions for three successively broadened period bands of 70–120 s, 50–120 s, and 30–120 s. Synthetic seismograms were computed using GPU‐accelerated spectral‐element simulations of seismic wave propagation in 3‐D anelastic models, and Fréchet derivatives were calculated based on an adjoint‐state method facilitated by a checkpointing algorithm. The inversion involved 352 iterations, which required 18,600 wavefield simulations.SinoScope 1.0is described in terms of isotropic P‐wave (VP), horizontally and vertically polarized S‐wave velocities (VSHandVSV), and mass density (ρ), which are independently constrained with the same data set coupled with a stochastic L‐BFGS quasi‐Newton optimization scheme. It systematically reduced differences between observed and synthetic full‐length seismograms. We performed a detailed resolution analysis by repairing input random parametric perturbations, indicating that resolution lengths can approach the half propagated wavelength within the well‐covered areas.SinoScope 1.0reveals strong lateral heterogeneities in the lithosphere, and features correlate well with geological observations, such as sedimentary basins, Holocene volcanoes, Tibetan Plateau, Philippine Sea Plate, and various tectonic units. The asthenosphere lies below the lithosphere beneath East and Southeast Asia, bounded by subduction trenches and cratonic blocks. Furthermore, we observe an enhanced image of well‐known slabs along strongly curved subduction zones, which do not exist in the initial model.