【摘要】 根据双相介质弹性波方程,并对弹性波方程进行分离得到了膨胀波方程。利用高阶差分对膨胀波方程进行数值模拟,边界处理采用完全匹配层的吸收边界条件,算法实现了任意高阶差分和自动加载边界条件的纵波方程正演模拟。计算结果表明,在双相各向同性介质中存在快纵波、慢纵波,两种纵波有明显的区别,快纵波的速度远大于慢纵波的速度。在分界面上,快纵波要产生透射快纵波、透射转换慢纵波,反射快纵波、反射转换慢纵波。慢纵波具有很强的衰减性,耗散系数越小,慢纵波越明显,反之亦然。该算法的高阶差分形式可以显著地降低数值频散,有效提高地震波正演计算的精度,适应性好,操作简便灵活。更多还原

【Abstract】 Based on the equation of elastic wave propagation in two-phase media and by separating the equation of elastic wave,the dilatational wave equation in two-phase in media is derived.The higher finite-difference (FD) and the perfectly matched layer boundary conditions are used to numerical simulation.The numerical simulation of the any higher-order difference and automatic loading boundary conditions is realized.The results of the calculation show that in the two-phase media,there are the fast dilatational wave and slow dilatational wave and they are different obviously.The velocity of the fast P wave is higher.On the interface,incident fast P-wave will generate two kinds of transmission and two kinds of reflection waves.The slow P-wave has intensive attenuation.The dissipation modulus is smaller,then the slow P-wave is more obvious,vice versa.The high-order FD pattern of this method can reduce the numerical dispersion markedly,and improve the accuracy of numerical simulation effectively and with good adaptability.The operation is convenient and flexible.更多还原