黏弹性参数地震波测定理论及应用实例

The method for viscoelastic parameter determination using seismic wave and its application example.

本文在频率域导出了线性流变体介质内的波动方程,同时也给出了黏弹性参数随空间坐标缓变时的近似波动方程表达式,明确了黏弹性参数和波相速度及各类波初动振幅之间的关系。作为例证,先用有限元方法生成黏弹性介质中的理论波场,用其直达波、透射波、反射波初动振幅获得了衰减系数,并进而反演得到黏滞性参数和弹性参数的比值。与模型值的对比表明,所得反演值合理,该方法可靠。

Wave equation in linear rheological medium is deduced in frequency domain, then approximate wave equation in the medium where viscoelastic parameters vary with location is also given in this paper. In addition, the relation between viscoelastic parameter and phase velocity or initial amplitude of each wave is shown definitely. In an example, theoretical wave field in viscoelastic medium is obtained by using finite element method; then attenuation coefficients are derived from the initial amplitudes of its direct wave, transmitted wave and reflection wave; and finally the ratio of viscous parameter to elastic parameter is estimated by inversion. The comparison with model values says that the inversion values are reasonable and the method is reliable.