FDM simulation of seismic waves, ocean acoustic waves, and tsunamis based on tsunami-coupled equations of motion
FDM simulation of seismic waves, ocean acoustic waves, and tsunamis based on tsunami-coupled equations of motion
复制标题
基于海啸耦合运动方程的地震波、海洋声波和海啸的 FDM 模拟
DOI：
10.1007/s00024-011-0430-z
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发表时间：
2013
期刊：
影响因子：
--
通讯作者：
and T. Furumura
中科院分区：
文献类型：
--
作者：
Maeda;T.;and T. Furumura
我们基于3D运动方程的有限差分法模拟，开发了一种新的统一建模技术，用于地震波、海洋声波和地震引起的海啸的全面模拟。利用这些方程中的压力梯度和重力之间的平衡，海啸传播自然地被纳入基于运动方程的模拟中。新开发的海啸耦合方程的并行计算的性能，使用区域划分程序显示出高效率系数与大量的CPU内核。模拟结果表明，近场项与地震波产生的浅源地震导致永久的同震地表变形，这引起了初始海啸的海面上。海啸的传播沿着海面作为重力波，和海洋声波在海水中的自由表面和海底之间的高频多次P波反射，也清楚地表明了本模拟。我们发现，我们的结果和其他模拟的基础上的分析模型和Navier-Stokes方程得到的海啸波形之间有很好的一致性，表明海啸耦合模拟模型的有效性。基于这种模拟，我们表明，海洋声波的振幅的比值的海啸的高度，这两个都是由地震产生的，强烈地依赖于地震破裂的上升时间。该比率可用于更详细地了解俯冲带地震的震源破裂过程，并用于实施针对慢海啸地震的改进的海啸警报系统。
We have developed a new, unified modeling technique for the total simulation of seismic waves, ocean acoustic waves, and tsunamis resulting from earthquakes, based on a finite difference method simulation of the 3D equations of motion. Using the equilibrium between the pressure gradient and gravity in these equations, tsunami propagation is naturally incorporated in the simulation based on the equations of motion. The performance of the parallel computation for the newly developed tsunami-coupled equations using a domain partitioning procedure shows a high efficiency coefficient with a large number of CPU cores. The simulation results show how the near-field term associated with seismic waves produced by shallow earthquakes leads to a permanent coseismic deformation of the ground surface, which gives rise to the initial tsunami on the sea surface. Propagation of the tsunami along the sea surface as a gravity wave, and ocean acoustic waves in seawater with high-frequency multiple P-wave reflections between the free surface and sea bottom, are also clearly demonstrated by the present simulations. We find a good agreement in the tsunami waveform between our results and those obtained by other simulations based on an analytical model and the Navier–Stokes equations, demonstrating the effectiveness of the tsunami-coupling simulation model. Based on this simulation, we show that the ratio of the amplitude of ocean acoustic waves to the height of the tsunami, both of which are produced by the earthquake, strongly depends on the rise time of the earthquake rupture. This ratio can be used to obtain a more detailed understanding of the source rupture processes of subduction zone earthquakes, and for implementing an improved tsunami alert system for slow tsunami earthquakes.