中国南北带地壳上地幔三维面波速度结构和各向异性  

THREE DIMENSIONAL SHEAR WAVE VELOCITY AND ANISOTROPY OF CRUST AND UPPER MANTLE IN THE CHINA NORTH-SOUTH EARTHQUAKE BELT

作　　者：陈立华[1] 宋仲和[1] 安昌强 陈国英[1] 庄真[2] 傅竹武[2] 胡家富[2] 吕梓龄[2] 

机构地区：[1]国家地震局地球物理研究所,北京100081 [2]云南大学,昆明650091

出　　处：《地球物理学报》1992年第5期574-583,共10页Chinese Journal of Geophysics

基　　金：国家自然科学基金会资助的课题

摘　　要：本文用长周期763地震仪面波群速度资料反演了中国南北带及邻区的三维速度结构.其中采集238条瑞利波和358条勒夫波混合频散曲线,使用均等显示滤波方法,并以4°×4°为一格将我国境内分为147格.用随机逆反演方法得到了研究区16格的纯路径频散.面波速度结构及演结果表明:1.莫霍界面深度一般在40—50km之间,最深达65km.总趋势是从东到西加深,且在南北带西侧南北两端向中部明显加深,东侧变化小.2.地幔顶部普遍出现很厚的低速层,上界面一般埋深60—80km.上地幔顶盖厚度一般为20—60km,速度为4.30—4.50km/s.3.研究区普遍存在各向异性,而且勒夫波和瑞利波速度的差值(V_(SV)—V_(SH))的绝对值随深度有增大的特点,在南北带南部和西北部V_(SV)—V_(SH)各向异性现象更为明显.In this study, the three dimensional shear wave velocity in the China north-south earthquake belt and the neighbor area is inverted by useing long period date of 763 seismograph. Ray-leigh wave dispersion dates of 238 paths and love wave dispersion dates of 358 paths have been obtained by applying the 'display-Equality filter frequency-time analysis' technique. The pure-path dispersions for 16 grids of 4°×4° grids in China have been extracted by using the modified 'grid-dispersion inversion' method from the mixed-path dispersion dates. The results show 1. The thicknesses of the crust are about 40-50km, the thickest thickness is 65km, the depth of Moho deepen from east to west in tota area and from north or south to middle in west area. 2. Low velocity layers exist generally in the upper mantle, the depths are about 60-80 km. the thicknesses of layers above Low velocity layers are about 20-60 km, the velocities are about 4.30-4.50 km/s. 3. The anisitropy show that the differences of love wave and rayleigh wave velocity (V-VsH) increase with the depth.

关 键 词：地壳 上地幔 地震 面波 速度 

分 类 号：P315.3[天文地球—地震学]