青藏高原及邻区大地水准面异常场源结构  

THE STUDY OF GEOID ANOMALY SOURCES IN QINGHAI TIBET PLATEAU AND ITS ADJACENT REGIONS

作　　者：方剑[1] 

机构地区：[1]中国科学院测量与地球物理研究所,湖北武汉430077

出　　处：《地学前缘》2001年第4期449-452,共4页Earth Science Frontiers

基　　金：国家自然科学基金资助项目 ( 49734 0 15 );国家"九五"攀登项目"现代地壳运动的研究"

摘　　要：以青藏高原及邻区地形、地震层析成像、沉积层底面、Moho面及岩石层底面资料为基础 ,讨论了由地形起伏、地球内部各界面以及物质密度不均匀引起的大地水准面异常的计算方法 ,正演计算出青藏高原及邻区岩石圈内部物质不均匀产生的大地水准面异常 ,并把从全阶大地水准面异常中扣除正演模拟得到的岩石圈大地水准面异常与不同阶次波段的大地水准面进行比较 ,以寻求表示青藏高原及邻区地幔物质不均匀的大地水准面异常球谐函数的最佳阶次。结合地震层析成像资料分析结果得出 ,表示青藏高原及邻区下地幔、上地幔及岩石圈物质不均匀的大地水准面异常球谐函数的阶次范围分别为 2 6阶 ,7 60阶和 61 3 60阶。The paper discusses computation method of geoid anomaly due to topography, interfaces and density inhomogeneity in the Earth. And then, simulates the middle short wavelength geoid anomalies in Qinghai Tibet Plateau and its adjacent regions by using the results of tectonic and density data, which deducted from data of tomography, seismic sounding and magnetotelluric sounding. The geoid anomaly caused by Moho discontinuity is similar to that caused by topography, but the undulation is much less than the latter. The simulation geoid anomaly due to lithosphere is deducted from the geoid anomaly, and the geoid anomaly due to mantle is got. Contrasting the geoid anomaly due to mantle with the geoid anomaly calculated by using geo potential model of different order, it shows that the geoid anomaly of 2 6 order corresponds to the geoid anomaly due to lower mantle, the geoid anomaly of 7 60 order to the geoid anomaly due to upper mantle, and the geoid anomaly of 61 360 order to the geoid anomaly due to lithosphere.

关 键 词：青藏高原 大地水准面异常 球谐函数阶次 场源结构 重力异常 岩石圈 

分 类 号：P22[天文地球—大地测量学与测量工程]