利用祁连山地区(36°～ 42°N,96°～104°E) 38个台站2014年8月-2015年12月的垂直分量连续背景噪声记录,获得了台站对之间的互相关函数和瑞利面波相速度频散曲线,采用基于射线追踪的面波频散直接反演方法,得到了观测台站下方5 ～40 km深度范围内的S波速度分布图像.结果表明:在5 km深度处,速度结构分布特征与地表构造分布存在一定的相关性,松散沉积层厚度影响明显;在18 km深度处,S波速度横向不均匀性明显,呈现为高低速相间不同尺度大小的区域性.同时,5 ～ 20 km深度范围内速度随深度增加而逐渐增加,其变化幅度为0.2 km/s;在30 km深度处,祁连和门源地区高低速相间分布明显;在35 ～ 40 km深度,随深度增大,祁连山北缘断裂带、托莱山断裂、冷龙岭断裂带以北地区为高速区,以南为低速区.%Using the vertical component of continuous background noise records of 38 stations located in the Qilian Mountains (36°N ～ 42°N,96°E ～ 104°E),and the record time was from August 2014 to December 2015,then we obtained the cross correlation function of all seismic station pairs and the velocity dispersion curve of Rayleigh wave.The velocity distribution of the S wave in the depth range of 5 ～ 40 km and is obtained by using the direct inversion method of surface wave dispersion based on ray tracing.The result shows that there is a certain correlation between the velocity structure distribution and the tectonic distribution at the depth of 5 km.And the thickness of the sedimentary layer has obvious effect.The S-wave velocity has an obvious lateral heterogeneity and shows different scales of the regional at the depth of 18 km.Meanwhile,the velocity increases with the depth,and the variation range is 0.2 km/s at the depth of 5 ～ 20 km.And the high and low speed phases of Qilian and Menyuan areas are obviously distributed at a depth of 30kmn.The north of the Qilian Mountains,the Tuolaishan fault,the Lenglongling fault zone,the north of the Lenglongling fault zone,and the south of the Lenglongling fault zone,which may be a manifestation of different blocks at the deep boundary in the depth of 35 ～ 40 km.
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