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通过时频分析法从海底环境噪声数据中提取界面波频散曲线,进而采用非线性贝叶斯反演方法估算海底沉积物厚度、剪切波速度、压缩波速度和密度等参数及其不确定性。参数的最大后验概率(MAP)估计值和边缘概率分布分别通过自适应单纯形模拟退火法和Metropolis-Hastings采样法在各参数先验区间内搜索获得,采用贝叶斯信息准则(BIC)从不同参数化模型中选择最优模型。界面波频散曲线反演结果表明:满足实测数据的最优海底模型结构为3层均匀分布剪切波速度剖面结构,海底深度的反演精度在800m以内,比起压缩波速度和密度,剪切波速度的不确定性更小,对界面波频散曲线更敏感。
The time-frequency analysis method is used to extract the dispersion curve of interface waves from the seafloor environmental noise data. Then the non-linear Bayesian inversion method is used to estimate the sediment thickness, shear wave velocity, compressional wave velocity and density, and their uncertainties Sex. The maximum posteriori (MAP) estimates and edge probability distributions of the parameters were obtained by searching the prior interval of each parameter by adaptive simplex simulated annealing method and Metropolis-Hastings sampling method, using Bayesian Information Criterion (BIC) Select the best model among different parametric models. The results of in-plane dispersion curves show that the optimum seafloor model satisfying the measured data is a 3-layer uniform distribution of shear wave velocity profile, and the inversion accuracy of seafloor depth is within 800m. Comparing with the velocity and density of compressional wave, The uncertainty of the shear wave speed is smaller and the dispersion curve of interface wave is more sensitive.