Abstract

The problem of tsunami warning and the use of the grid-characteristic method developed for studying wave processes in heterogeneous media is addressed. A multilayer geological model with curved boundaries and contrasting elastic parameters is considered. Various seismic survey methods, as well as different geometries of the boundaries, different values of rock densities, and various longitudinal and shear wave velocities, are examined. The boundary value problem is numerically solved jointly for the elastic and acoustic wave equations (seismic wave propagation in rocks and water layer, respectively). We use the numerical grid-characteristic method with combined structured curvilinear and regular computational grids. The wave velocity fields (velocity as derivative of displacement) and stress fields are calculated and analyzed. Synthetic seismograms are calculated for the coastal zone. It is found that some specific features of seismograms and some wave modes can be used for tsunami warning. The optimal parameters of seismic surveying are determined. Numerical simulation of wave propagation effects is used for these purposes. The proposed numerical grid-characteristic method can be used in forward numerical modeling in order to interpret seismograms recorded in the coastal zone.

中文翻译：

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沿海地区地震波传播的数值模拟

摘要

讨论了海啸预警问题和开发用于研究非均质介质中波浪过程的网格特征方法的问题。考虑具有弯曲边界和对比弹性参数的多层地质模型。研究了各种地震勘测方法，以及边界的不同几何形状，不同的岩石密度值以及各种纵向和剪切波速度。对于弹性波和声波方程（分别在岩石和水层中传播），通过数值方法共同解决了边值问题。我们将数值网格特征方法与结构化曲线网格和规则计算网格结合使用。计算并分析了波速场（速度是位移的导数）和应力场。计算沿海地区的合成地震图。发现地震图的某些特定特征和某些波模式可用于海啸预警。确定了地震勘测的最佳参数。为此目的，使用了波传播效应的数值模拟。提出的数值网格特征方法可用于正演数值模拟，以解释沿岸带记录的地震图。