中国东北地区噪声层析成像  

Ambient noise tomography in northeast China

作　　者：潘佳铁[1] 吴庆举[1] 李永华[1] 余大新[1] 

机构地区：[1]中国地震局地球物理研究所,北京100081

出　　处：《地球物理学报》2014年第3期812-821,共10页Chinese Journal of Geophysics

基　　金：中国地震局地球物理研究所基本业务费专项(DQJB11B04);国家自然科学基金(41104029;90814013);中国地质调查局地质调查工作项目(1212011121072);深部探测技术与实验研究专项(SinoProbe-02-03);科技部国际合作专项(2011DFB20210)共同资助

摘　　要：中国东北地区是中国唯一的深震孕育区，获取该区的壳幔结构，对于研究板块俯冲、深震以及火山活动等有重要的科学意义.本文利用该区159个固定台站2011年1月至2012年6月和27个流动台站2011年1月至2011年6月间的垂向波形连续记录，计算了台站间的预估格林函数，并采用基于连续小波变换的时频分析方法，测量了双台路径上瑞雷波的群速度和相速度频散曲线.通过质量控制和筛选，最终得到了2204条路径上周期5~40 s的群/相速度频散曲线.检测板测试表明，反演结果可以达到2°×2°的分辨.利用Ditmar ＆ Yanovskaya反演方法，我们得到了研究区（105°E—135°E，39°N—52°N）周期8~30 s的瑞雷波的群速度和相速度分布图.不同周期的群/相速度分布图，反映了不同深度S波速度的横向变化情况.研究结果显示：中国东北地区的地壳上地幔S波速度结构存在横向非均匀性.短周期（如8 s）的群/相速度分布与地表地质构造具有明显的相关性，具体来说，山区显示为高速，沉积盆地显示为低速；随着周期的增大（如15 s，22 s），地形的控制作用相对减弱；较长周期（如30 s）的群/相速度分布与地壳厚度密切相关.Northeast China is the only one of the deep earthquake zone in China. In order to study the subduction of the west Pacific plate, the deep earthquakes and volcanic activity, it has very important scientific significance to obtain the crustal and upper mantle structure of this region. By using the vertical component of continuous data, recorded by 159 permanent stations from January 2011 to June 2012 and 27 portable stations from January 2011 to June 2011 in northeast China, we calculated the inter-station Green functions, and measured the group velocity and phase velocity dispersion curves of Rayleigh wave by using the frequency-time analysis method based on continuous wavelet transform. According to quality control and screening, we finally obtained 2204 group/phase velocity dispersion curves at periods ranging from 5 s to 40 s. Checkerboard tests show that the inversion results have a good resolution of 2 ° ×2 °. By utilizing Ditmar ＆ Yanovskaya method, we got the Rayleigh wave group velocity and phase velocity maps at periods between 8~30 s in the study area （105°E—135°E, 39°N—52°N）, which revealed the lateral changes of S-wave velocity at different depths. The results showed that the crust and upper mantle S-wave velocity structures have lateral heterogeneity. Group/phase velocity maps at short period （e.g. 8 s） are well related with the geology units on the surface,with high-speed anomalies corresponding to the main mountain ranges and low-speed anomalies coinciding with the major sedimentary basins. But the effect controlled by the topography becomes weaker at the intermediate periods （e.g. 15 s, 22 s）. For group/phase velocity maps at longer periods （e.g. 30 s）, they are closely related with crustal thickness.

关 键 词：中国东北 噪声成像 瑞雷波 群速度 相速度 

分 类 号：P315[天文地球—地震学]