中国东南大陆及陆缘地带的瑞利波频散与剪切波三维速度结构  

THE RAYLEIGH WAVE DISPERSION AND THREE DIMENSIONAL VELOCITY STRUCTURE IN CONTINENT AND ITS MARGIN OF SOUTHEAST CHINA

作　　者：滕吉文[1] 张中杰[1] 胡家富[2] 王光杰[1] 

机构地区：[1]中国科学院地质与地球物理研究所,北京100101 [2]云南大学,昆明650091

出　　处：《地球物理学报》2001年第5期663-677,共15页Chinese Journal of Geophysics

基　　金：中国科学院重点项目 (KZ95 2 -S1 -41 0 ) ;国家自然科学基金资助项目 (4 0 0 740 2 0 )

摘　　要：利用我国地震台站记录的瑞利波观测资料 ,通过适配滤波频时分析技术进行数据处理 ,获得了穿越我国东南及陆缘地区的瑞利波频散 .使用随机反演理论取得了东南大陆及陆缘地带 4°× 4°网格的纯路径频散数据 .在网格反演的基础上使用Harkrider的面波反演程序求得了该区剪切波的三维速度结构 .结果表明 :1 .华南大陆Moho界面埋深为 3 0— 40km ,并由西向东逐渐减薄 ,在陆缘与浅海地域为 2 5— 2 8km ,具有明显的分区特征 .2 .上地幔低速层埋深为 6 0— 1 5 0km ,变化幅度较大 ,这与深部断裂分布及深层过程有关 ,但NS向剖面上各界面的起伏变化均比EW向剖面平缓 .3 .东南陆缘是东亚大陆的海陆过渡带 ,在深部表现为Moho界面埋深和地壳平均速度降低的地带 ,地幔深部界面的起伏形态充分表明 ,深浅介质结构和物质耦合的不均匀性 .HTWTIn this study,the dispersion of Rayleigh waves crossing Southeast China and its continental margin is determined by applying the (Matched-filter frequency-time analysis) technique to CDSN mid-long period data. The technique improves the resolution of dispersion measurement over a broader period range with reduced systematic errors. An improved grid dispersion inversion is proposed to extract pure-path dispersion curves in 4°×4° grid from the mixed path dispersion data. On the basis of the grid dispersion inversion,we use Harkrider surfer Wave inversion program to study the three dimension shear wave velocity structure to depth of 200km. A detailed description on the lateral heterogeneity in the crust and upper mantle of Southeast China is provided. The results show that:1. The depth of Moho is generally 30_40km in continent region of Southeast China and 25_28km in its continental margin. The crustal thickness is thin from west,and the features of regional division are quite clear. 2. The depth of the low velocity layer in the upper mantle is 60_150km in continent of southeast China. Distribution of deep faults and deep internal processes has something to do with the great variational amplitude for the lower velocity layer in the upper mantle. 3. The Southeast margin of China is a transition belt between continent and Sea. Its characteristics are shown that there is a low velocity zone and the depth of the Moho is shallow. The undulate shape of deep interface of the mantle makes clear,moreover,its cupping between deep and shallow and structure is inhomogeneity. WTHZHTH

关 键 词：地震面波 三维速度结构 软流层 秦岭-大别造山带 深层动力过程 华南大陆 瑞利波频散 

分 类 号：P542[天文地球—构造地质学] P548.2[天文地球—地质学]