平面波在粘滞性界面上的反射特征研究  

Reflection features of planar waves from visco-interfaces

作　　者：孙成禹[1] 张玉亮[1] 万学娟[1] 

机构地区：[1]中国石油大学(华东),东营257061

出　　处：《地球物理学进展》2007年第2期609-616,共8页Progress in Geophysics

基　　金：山东省优秀中青年科学家科研奖励基金(02BS123).资助

摘　　要：当介质中存在按照一定方向排列的裂隙时,会在该区域形成接触程度不好的界面.当有地震波传播时,界面两侧的质点不再满足位移连续的条件,位移差与该点的应力有关.从而引起质点间的滑动,形成粘滞性界面.界面的这种特性可以用切向柔量和法向柔量来表示,柔量值越大,界面的接触程度和质点位移的连续性都越差.文中详细推导了平面波在粘滞性界面上的反射和透射系数公式,通过数值算例证明了粘滞性界面上的反射系数与入射波频率有关的性质.并说明了界面的粘滞性会在一定程度上影响到反射波的AVO特性.且当平面P波入射时,法向柔量对反射P波和转换波的影响均大于切向柔量的影响.Imperfectly bonded interfaces maybe exist with some aligned cracks in the media. Displacement across this interface is not required to be continuous as seismic waves propagating through this region. The displacement discontinuity is taken to be related to the stress across the interface, which cause the adjacent particles slip and form a viscointerface. This behavior can be expressed by two compliances, shear compliance and normal compliance. With the increasing of interface compliances, the bonding level becomes poorer and the displacement error becomes larger. Reflection and transmission equations of planar waves incident to such interfaces are deduced in detail in this paper. Through some numerical examples, the property that reflections and transmissions from visco-interface are related to frequency is emphasized. Also, the viscosity can affect AVO characters of the reflection waves to some extent. It is showed that the normal compliance has much influence on P-P and P-S reflections than that shear compliance do when the incident wave is P-wave.

关 键 词：地震波 反射与透射 粘滞性界面 线性滑动界面 柔量 

分 类 号：P631[天文地球—地质矿产勘探]