【摘要】 2006年底,我们沿"张渤地震带"布设了一条从唐海—北京—商都的宽频带地震台阵剖面.本文利用台阵记录的远震波形资料,通过接收函数和面波联合反演对剖面下方100km深度范围内地壳上地幔S波速度结构进行了研究.结果表明剖面东段莫霍面深度约30～34km,西段深度约38～42km,平原与山区的过渡地带地壳厚度变化较快.地壳内部10～20km深度范围内存在多个低速体.在唐山7.8级地震震区附近Moho面出现小幅度隆起,中地壳存在明显的S波低速体.张家口以西,剖面下方10～20km范围内存在两个S波低速体,张北6.2级地震发生在这两个低速体之间狭小的高速区.在观测剖面附近,历史上发生的4个大震都与壳内低速体的分布有关.张家口以东,上地幔普遍存在低速层,顶部埋深在60～80km之间,并表现出明显的东部浅西部深的特点.更多还原

【Abstract】 At the end of 2006,We deployed a passive broadband seismic array along Zhangjiakou-Bohai seismic zone,from Tanghai,traversing through Beijing,to Shangdu.The S-wave velocity structures of the crust and upper mantle down to 100 km depth along the profile are determined by joint inversion of receiver functions and phase velocity dispersion curves.Our results show that the Moho depths are deeper in west than those in east.The Moho depths vary between 30～34 km and 38～42 km in the eastern and western sections respectively,and vary rapidly in the transition zone between mountainous region and plain.There exist several low velocity zones about 10～20 km under the profile.The crustal thickness is thinner in the vicinity of Tangshan Ms7.8 earthquake area and there exists a distinct low velocity body in mid-crust.To the west of Zhangjiakou,there are two low velocity zones about 10～20 km under the stations.Zhangbei earthquake of magnitude 6.2 occurred between the two low velocity zones.We found that the hypocenters of four large earthquakes in history are obviously correlated with the low-velocity bodies.To the east of Zhangjiakou,the low-velocity bodies are ubiquitous in the upper mantle,with the top buried at depths between 60～80km,shallower in the east and deeper in the west.更多还原