Full-waveform inversion of multicomponent data can provide an improved estimation of medium parameters using both compressional- and shear-wave information. However, most earlier studies that involved a full-waveform inversion of ocean-bottom data are based on acoustic anisotropic or elastic isotropic approximations. Here, we consider realistic elastic anisotropic media and develop an efficient full-waveform inversion framework for estimating model parameters. We simulate seismic wavefields using a previously developed coupled acoustic/elastic wave propagator that implements a mimetic finite-difference method with fully staggered grids to accurately handle the fluid/solid boundary conditions. The algorithm employs a multiscale approach starting from low frequencies and incorporating higher frequency bands in the later inversion stages. We analyse the influence of different types of input data on the accuracy of the inverted anisotropy parameters for hard and soft water bottoms. The employed misfit function incorporates information from both hydrophones and ocean-bottom geophones. Numerical examples indicate that injecting multiple data components simultaneously increases the complexity of the objective function and often degrades the quality of the estimated medium parameters. Thus, we propose a sequential strategy using a single data component at a time. Pressure (hydrophone) data alone can provide satisfactory results if long offsets (i.e., with the offset/depth ratio ≥ 3) are available. Adding the horizontal particle-displacement or -velocity components increases the accuracy of the estimated shear-wave vertical velocity () and P-wave normal-moveout () velocity, especially for strongly heterogeneous sub-water-bottom models.

中文翻译：

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各向异性介质多分量海底数据弹性全波形反演方法

多分量数据的全波形反演可以使用压缩波和剪切波信息提供改进的介质参数估计。然而，大多数涉及海底数据全波形反演的早期研究都是基于声学各向异性或弹性各向同性近似。在这里，我们考虑现实的弹性各向异性介质，并开发一个有效的全波形反演框架来估计模型参数。我们使用先前开发的耦合声/弹性波传播器来模拟地震波场，该传播器采用完全交错网格的模拟有限差分法来准确处理流体/固体边界条件。该算法采用从低频开始并在后期反演阶段结合更高频段的多尺度方法。我们分析了不同类型的输入数据对硬水底和软水底反演各向异性参数精度的影响。所采用的失配函数结合了来自水听器和海底地震检波器的信息。数值示例表明，同时注入多个数据分量会增加目标函数的复杂性，并且通常会降低估计介质参数的质量。因此，我们提出了一次使用单个数据组件的顺序策略。如果可以获得长偏移距（即偏移距/深度比≥ 3），则仅压力（水听器）数据就可以提供令人满意的结果。添加水平粒子位移或速度分量可以提高估计的剪切波垂直速度的准确性（) 和 P 波正常时差 (）速度，特别是对于强非均质的水下模型。