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本文主要目的是研究二维随机介质中的散射衰减规律,并确定最小散射角的取值范围.首先基于随机介质理论构建相应的随机介质模型,然后利用间断有限元方法求解二维弹性波动方程,模拟地震波在随机介质中的传播过程,最后使用振幅衰减法,来估计随机介质的逆品质因子.本文模拟了不同频率地震波在不同参数的随机介质中的传播过程,统计结果表明,随机介质的逆品质因子与扰动标准差的平方成正比;当散射体尺寸与波长相当或小于波长时,随着散射体尺寸的增加,地震波振幅的散射衰减增强,高频地震波散射衰减作用更强;二维高斯型随机介质中,P波的最小散射角在60°~90°范围内.
The main purpose of this paper is to study the law of scattering attenuation in two-dimensional random media and to determine the range of the minimum scattering angle.Firstly, a stochastic medium model is constructed based on stochastic medium theory, and then the discontinuous finite element method is used to solve two-dimensional elastic wave equation, The propagation process of seismic waves in random media is simulated, and finally the amplitude attenuation method is used to estimate the inverse quality factor of random media.In this paper, we simulate the propagation of seismic waves of different frequencies in random media with different parameters. The statistical results show that the inverse of random media The quality factor is proportional to the square of the standard deviation of the disturbance. When the size and wavelength of the scatterer are equal to or less than the wavelength, the scattering attenuation of the seismic amplitude increases with the increase of the size of the scatterer, Type random medium, the minimum scattering angle of P wave is in the range of 60 ° ~ 90 °.