Poisson's ratio distribution in the upper crust around the A'nyemaqen suture zone and its adjacent areas

We obtained velocity structure and Poisson's ratio distribution in the upper crust by the high resolution refraction section (200-400km) which belongs to Maerkang - Gulang wide-angle reflection and refraction profile inversed from Pg and Sg data. Reliability of inversed model is improved using the phases identification error analysis, resolution calculation and choice of different initial models. The results reveal that the average Poisson' s ratio between 275-355km is as high as 0. 279 and P-wave velocity and S-wave velocity are banded laterally beneath the A' nyemaqen suture zone. The Kusaihu- Maqin fault and Zhouqu-Liandang fault are in zones of high Poisson's ratio and low velocity and the faults are boundaries of the Roergai basin and Qinling fold zone, respectively. The average Poisson's ratio of the Roergai basin which is on the south side of the A'nyemaqen suture zone is 0. 257 and the average Poisson's ratio of the West Qinling fold zone which is on the north side of the Animaqin suture zone is 0. 264.