摘要
收集了中国东北地区159个固定地震台2011年1月至2012年6月和27个流动地震台2011年1月至2011年6月间的垂向连续记录,根据噪声成像方法得到研究区（105°E—135°E,39°N—52°N）较短周期（8∽30 s）的瑞雷波群速度和相速度频散资料,再结合该区已有的天然地震长周期瑞雷波（36∽145 s）的群速度频散资料,我们反演得到了中国东北地区200 km以浅深度范围内的三维壳幔S波速度结构,并得到了该区的岩石圈厚度分布图.结果表明：研究区中、下地壳S波速度结构的横向分布,在重力梯度带两侧有很大的不同,以东地区显示为大范围的高速,以西地区则呈现为大面积的低速;松辽盆地下方岩石圈地幔表现为显著的高速,岩石圈地幔底界面深度可能在90∽100 km,薄的岩石圈盖层暗示东北地区的岩石圈可能发生了减薄;郯庐大断裂下方呈现出大范围的比较显著的低速特征,断裂下方上地幔顶部可能有热物质活动.
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 （NEC）, the pure path group and phase velocity dispersion curves of Rayleigh wave at short periods （8--30 s） were obtained by ambient noise tomography in the study area （105°E--135°E, 39°N--52°N）. Besides, the pure path group velocity of Rayleigh wave at longer periods （36-145 s） obtained from surface wave tomography were jointly used to invert for the 3- D S-wave velocity structure of crust and upper mantle above the depth of 200 km beneath NEC, and the lithospheric thickness map was presented. This study shows that the S-wave velocity structures in the middle and lower crust on the two sides of the Da Hinggan Ling gravity gradient line are very different~ obvious high speed is observed to the east while obvious slow speed is observed to the west in large areas. The lithospheric mantle beneath the Songliao Basin is imaged with remarkable high speed the depth of the lithospheric mantle bottom interface may be 90-- 100 km. Here the thin lithosphere lid may imply that lithospheric thinning may have occurred in NEC. A wide range of relatively slow-speed characteristics is imaged around Tanlu fault in upper mantle, indicating that there may be hot material up-welling beneath the faults.
出处
《地球物理学报》
SCIE
EI
CAS
CSCD
北大核心
2014年第7期2077-2087,共11页
Chinese Journal of Geophysics
基金
国家自然科学基金(41104029
90814013)
中国地震局地球物理研究所基本业务费专项(DQJB11B04)
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)共同资助
关键词
中国东北
面波层析成像
群速度
相速度
S波速度结构
岩石圈厚度
Northeast China
Surface wave tomography
Group velocity
Phase velocity
S-wavevelocity structure
Lithospheric thickness
