- 责任者：Chen Jianxiong (Institute of Geophysics ; China Earthquake Administration ; Beijing 100081 ; China) ; Wang Baoshan
- 刊名：Earthquake Research in China
- 出版年：2011
- 卷期：27(1)
- 关键词：空气枪 ; air guns ; 低速带 ; low-velocity zones ; 华北地区 ; North China
- 页码：p.49-55
- 图表：6 illus., 18 refs.
- 分类号：1600
- issnNo：ISSN1001-4683
- isbnNo：CN11-2008/P
The low velocity zone is a mechanical weak band in the crust, which plays an important role in breeding of earthquakes. Artifical detection and nature earthquake tomography both show that low velocity layers exist in different depths in North China. The authors analyzed the high-resolution data detected by large volume airgun source in North China in order to put further constraint on the properties of the low velocity layers there. The results showed that synthetic seismograms can not only explain the travel time of various seismic phases, but also obtain the amplitude ratio of PmP and Pg. The results of our modeling include: 1) the average thickness of crust in this area is 33 km; and 2) there exists a low velocity layer in both the upper and lower crust in this region. By comparing the heat and magnetotelluric data, the authors conclude that the low velocity layers in the upper and lower crusts were caused by fluid and thermal effect respectively.