Application of Amplitude Ratio Profiles Extracted with Prestack Kirchhoff Integral Migration

The Z component and X component profiles of seismic waves extracted with the prestack Kirchhoff integral migration could approximate to the primary wave （P wave） and converted shear wave （PS wave） profiles under certain conditions. The relative change of their reflection amplitude reflects the formation stress anomaly and subsurface media anisotropy. The principle and method for extracting amplitude ratios were studied and the application of amplitude ratio profiles was also examined when processing and interpreting actual seismic data. The amplitude ratio profile is an effective supplementary means of identifying the stratigraphic boundary and lithology.

Combined migration velocity model-building and its application in tunnel seismic prediction

We propose a combined migration velocity analysis and imaging method based on Kirchhoff integral migration and reverse time migration,using the residual curvature analysis and layer stripping strategy to build the velocity model.This method improves the image resolution of Kirchhoff integral migration and reduces the computations of the reverse time migration.It combines the advantages of efficiency and accuracy of the two migration methods.Its application in tunnel seismic prediction shows good results.Numerical experiments show that the imaging results of reverse time migration are better than the imaging results of Kirchhoff integral migration in many aspects of tunnel prediction.Field data show that this method has efficient computations and can establish a reasonable velocity model and a high quality imaging section.Combination with geological information can make an accurate prediction of the front of the tunnel geological structure.

Protecting wild yak (Bos mutus) species and preventing its hybrid in China

China has made efforts to protect wild yak （Bos mutus） species and prevent the hybrids between wild yak and domestic yak （Bos grunniens） species.At present,wild yak population of a reasonable estimate would be over 70,000.Due to conservation efforts in environmental protection and ecological construction such as the Wildlife Protection and Nature Reserve Construction Project,the ＂Grain-for-Green＂ Project and the Natural Forest Resources Protection Project,the number of wild yaks is increasing.In general,Tibetan Plateau＇s ecosystem is getting better and its environmental quality shows a gradual improving trend.Tibetan Plateau is one of the world＇s cleanest regions called as the ＂Third Pole＂.In order to preserve the genetic pool of wild yaks,local pastoralists and polices drive off the wild male yaks from the domestic yak herds by making noise （banging washbasins,pots,etc.） or driving cars.Local government also incentivizes the culling of domestic yaks found in wild herds.For the sake of the biological and genetic features of this wild species,and the pastoralist way of life,wild yaks should continuously be protected to keep their genetic integrity.We appeal plans to investigate the gene pollution of wild yaks in some important distribution regions of this species.In the face of hybridizing with domestic yaks,proper guidance is urgently needed to address genetic pollution and protect the genetic integrity of wild yaks.