由裂隙引起的三分量资料中的泛张各向异性

Fracture-dependent extensive dilatancy anisotropy in three-component data

文中利用有限差分正演模拟方法分别对合裂隙的双层模型（EDA—各向同性）、横向各向同性双层模型（PTL—各自同性）、不含裂隙的双层模型（各向同性—各向同性）等三种情况下的三分量记录进行分析，可以看到三分量记录上存在着由裂隙引起的泛张各向异性。第一种情况，可以看到明显的横渡分裂现象，且在Y分量上出现很强的P-SH波；第二种情况，也有横渡分裂现象，在X分量上可观测到P－SV波，在Y分量上只有单一的横渡信息，却观测不到P－SH波；第三种情况，三分量记录无横渡分裂现象，只在Y分量上观测到独立的横波信息。文中提供了一个含煤层地区的X和Y分量记录，证实在Y分量上的P－SH波是由煤层的裂缝引起的。

By using fln1techdlfference forward modeling method,we analyse the three-com-ponent seismograms of some dual-layer models (EDA-isotropy, PTL-isotropy andisotropy-isotropy models ). The extensive dilatancy anisotropy resulting from frac-tures can be seen in three-component data. First model brings three component syn-thetic seismograms which show obvious shear wave splitting and clear P-SH wavein Y component. In the second model case, shear wave splitting exists also , P-SVwave can be found in X component,and Y component only shows single shear wavewithout P-SH wave. Three-component seismograms of the third model have noshear wave splitting, and only pure shear wave can be observed in Y component.The article offers X and Y component data which were collected from coal seamarea;and it is proved that P-SH wave in Y component results from coal seam frac-tures.