用DSS资料研究首都圈地区的地壳结构

A Study on Crustal Structure of Tianjin-Beijing-Chicheng DSS Profile

利用几种不同的一维反演方法对天津—北京—赤城剖面的DSS(deep seismic sounding)数据进行了处理,结果显示:沿剖面基底面北浅南深,但C界面和M界面北深南浅,存在镜像关系;地壳平均速度华北盆地较低,燕山下方较高;燕山隆起和华北盆地的交界处曾多次发生过5.0级以上地震,且在该过渡带上,多条深大断裂成北北东、北东向穿过该剖面,推断首都圈地区地震的发生与莫霍面的局部隆起、速度结构的急剧变化以及深大断裂的存在具有密切关系。

Results of crustal structure will be imperfect results will be more ideal if we use multi-methods when d if a single method is used, but the ealing with profile data. Travel-time data from Tianjin-Beijing- Chicheng DSS （Deep Seismic Sounding） profile are inverted by using various one-dimensional inversion methods. The results of inversion show that the south basement of the profile is deeper than the north one, but the crustal interface and Moho geometry are opposite. The average velocity of crust beneath North China Basin is lower than that beneath Yanshan Mountain. Many strong earthquakes （Ms≥5） have occurred on the border of North China Basin and Yanshan Uplift. In addition, two kinds of deep and huge faults go through the profile, with one trending NNE and the other trending NE. Therefore, it is believed that the occurrence of earthquake within the Capital Circle is closely related with the local uplift of Moho geometry, the rapid variation of crust velocity structure and the effect of huge faults.