To complement velocity distributions, seismic attenuation provides additional important information on fluid properties of hydrocarbon reservoirs in exploration seismology, as well as temperature distributions, partial melting, and water content within the crust and mantle in earthquake seismology. Full waveform inversion (FWI), as one of the state‐of‐the‐art seismic imaging techniques, can produce high‐resolution constraints for subsurface (an)elastic parameters by minimizing the difference between observed and predicted seismograms. Traditional waveform inversion for attenuation is commonly based on the standard‐linear‐solid (SLS) wave equation, in which case the quality factor (Q ) has to be converted to stress and strain relaxation times. When using multiple attenuation mechanisms in the SLS method, it is difficult to directly estimate these relaxation time parameters. Based on a time domain complex‐valued viscoacoustic wave equation, we present an FWI framework for simultaneously estimating subsurface P wave velocity and attenuation distributions. Because Q is explicitly incorporated into the viscoacoustic wave equation, we directly derive P wave velocity and Q sensitivity kernels using the adjoint‐state method and simultaneously estimate their subsurface distributions. By analyzing the Gauss‐Newton Hessian, we observe strong interparameter crosstalk, especially the leakage from velocity to Q . We approximate the Hessian inverse using a preconditioned L‐BFGS method in viscoacoustic FWI, which enables us to successfully reduce interparameter crosstalk and produce accurate velocity and attenuation models. Numerical examples demonstrate the feasibility and robustness of the proposed method for simultaneously mapping complex velocity and Q distributions in the subsurface.

中文翻译：

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基于时域复值粘声波方程的全波形反演估计P波速度和衰减结构：方法

为了补充速度分布，地震衰减提供了有关勘探地震学中碳氢化合物储层的流体性质以及地震地震学中地壳和地幔中温度分布，部分融化和含水量的其他重要信息。全波形反演（FWI）作为最先进的地震成像技术之一，可以通过最小化观测到的地震图与预测地震图之间的差异，为地下（一个）弹性参数产生高分辨率约束。传统的衰减波形反演通常基于标准线性固体（SLS）波动方程，在这种情况下，品质因数（Q）必须转换为应力和应变松弛时间。在SLS方法中使用多种衰减机制时，很难直接估计这些弛豫时间参数。基于时域复值粘声波方程，我们提出了同时估计地下P波速度和衰减分布的FWI框架。由于将Q明确地包含在粘声波方程中，因此我们可以使用伴随状态方法直接导出P波速度和Q敏感度内核，并同时估计其地下分布。通过分析高斯-牛顿·黑森（Gauss-Newton Hessian），我们观察到强烈的参数间串扰，尤其是速度到Q。我们使用粘滞FWI中的预处理L‐BFGS方法对Hessian逆进行近似，这使我们能够成功减少参数间的串扰并产生准确的速度和衰减模型。数值算例表明了该方法同时绘制地下复杂速度和Q分布的可行性和鲁棒性。