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基于中蒙国际科技合作项目中获取的宽频带地震阵观测资料,利用提取到的周期为10~80 s的每个网格点瑞雷波相速度频散,反演得到了蒙古中南部下方地壳以及上地幔S波速度结构.结果表明:25 km深度处S波速度分布特征受地表构造形态控制,北部杭爱-肯特山脉为明显高速异常(约3.75~3.82 km/s),中南部戈壁沙漠为低速异常(约3.55~3.65 km/s);42 km深度处S波速度受地壳厚度影响,具有西北到东南逐渐增大的趋势,杭爱-肯特山盆下地壳相对较高的S波速(约4.1 km/s)是由盆地形成过程中拉伸作用导致盆地下地壳厚度减薄造成的;60~100 km深度范围内S波速度呈现南北高中部低的形态,分析认为中部戈壁低速异常与该地区新生代火山活动有关,而火山活动范围纵向上由中西部向中东部逐渐变深,横向由中东部向中西部逐渐变宽;此外,中东部地区地壳的隆起可能是由于火山活动引起的地幔热流上涌造成的.
Based on the broadband seismic array data obtained from the Sino-Mongolian International Cooperation in Science and Technology, the phase velocity dispersion of the Rayleigh wave at each grid point of 10 ~ 80 s was extracted and the crust below the central-southern Mongolia was obtained by inversion And the S-wave velocity structure of the upper mantle.The results show that the S-wave velocity distribution at 25 km depth is controlled by the surface structure, while the Hang-Ai-Kent range in the north is obviously high-velocity anomaly (about 3.75 ~ 3.82 km / s) (About 3.55 ~ 3.65 km / s). The S-wave velocity at 42 km depth is affected by the crustal thickness, and tends to increase gradually from northwest to southeast. The S-wave velocity of the lower Hanghai-Kent basin is relatively high About 4.1 km / s) is caused by the thinning of the lower crust in the basin due to the stretching during the basin formation. The S-wave velocities in the depth range of 60 ~ 100 km are in the low form of the north-south high-middle part. The analysis shows that the low- The Cenozoic volcanic activity in the area is related to volcanic activity. The range of volcanic activity is gradually deepening from the central and western parts to the middle part of the eastern part, and gradually widening from the central and eastern parts to the central and western parts. In addition, the uplift of the central and eastern crust may be caused by volcanic activities Mantle heat Upwelling caused.