晋中南地区地壳结构的初步研究

本文是对陕西长安、山西代县和太谷等地工业爆破的资料采用时间项法研究晋中南地壳结构的初步成果。文中首先结合长安爆破观测资料的总结,对时间项方法作一介绍。为使用太谷等缺乏起爆时刻的爆破资料,对时间项方法作了一些改进,使对于那些未有起爆时刻的爆破资料亦能用于确定时间项。使用上述爆破和各台记录的初动到时获得了晋中南地区的界面速度为7.95±0.04公里/秒,求得了41个点的时间项,取莫霍面以上介质的平均速度v0=6.4公里/秒反演求得了各点的莫霍界面深度,并对所得的结果结合晋中南地区的地震活动性及部分地震震源机制结果进行了初步的分析和讨论。

PRELIMINARY RESULTS OF THE INVESTIGATION OF THE CRUSTAL STRUCTURE OF THE SOUTH-CENTRAL PART OF SHANSI PROVINCE

In this study preliminary results are presented for the investigation of the crustal structure of the South- central part of Shansi Province by use of the time-term method,applied to the material obtained during several industrial explosions carried out in Chang-an,Dai Hsien and Taigu. An adaptation of the method is made for those explosions of which the origin times are not known. The velocity just below the M-discontinuity is found to be 7.95±0.04 km/sec. Assuming an average velocity of 6.4 km/sec,for the crust,the time-terms for 41 locations were obtained,whence the corresponding depths of the M-discontinuity were computed by inversion. The relation between these and the seismicity or mechanism of earthquakes in this area is briefly discussed.