阿尼玛卿缝合带及两侧上地壳泊松比分布  

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

作　　者：刘志[1] 张先康[1] 潘纪顺[1] 段永红[1] 杨卓欣[1] 

机构地区：[1]中国地震局地球物理勘探中心,郑州450002

出　　处：《地球物理学进展》2009年第5期1627-1635,共9页Progress in Geophysics

基　　金：国家自然科学基金重点项目(40334040);中国地震局地震联合基金项目(A07104)资助

摘　　要：本文通过对马尔康—古浪宽角反射和折射剖面高精度观测段(200-400 km)的Pg、Sg资料的分析解释,给出了该区段上地壳速度结构和泊松比分布.并利用震相识别误差分析、分辨率计算及不同初始模型筛选等方法,使走时反演结果的可靠性进一步提高.研究表明:对应于阿尼玛卿缝合带的275km-355 km桩号段内平均泊松比高达0.297,P波和S波速度呈横向高低速条带变化,库赛湖—玛沁断裂和舟曲—两当断裂基本上均位于高泊松比和低速带内,并分别处在缝合带与若尔盖盆地和西秦岭褶皱带的分界上.阿尼玛卿缝合带南侧的若尔盖盆地平均泊松比较低,约为0.257,北侧西秦岭褶皱带的平均泊松比为0.264.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＇ nyemaen 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.

关 键 词：阿尼玛卿缝合带 上地壳速度结构 泊松比.走时反演 

分 类 号：P315[天文地球—地震学] P313[天文地球—固体地球物理学]