摘要
泊松比做为了解地球内部介质一个非常重要的参数,在地震学上可以通过P波和S波速度的比值来确定.利用远震P波波形记录中包含的壳-幔速度间断面的Ps转换波及其多次反射转换波信息,采用在地壳厚度-波速比平面上对接收函数转换波能量的叠加搜索方法,可以测定台站下方区域内地壳的平均厚度和泊松比.我们对渤海湾盆地北西盆山边界地区68个宽频带台站近两年的远震记录资料进行了处理研究,得到了该区域的地壳厚度以及泊松比分布.结果表明,渤海湾盆地北西盆山边界的泊松比值分布横向变化复杂,山区侧与盆地侧存在明显差异;山区侧泊松比值分布相对均匀,盆地侧变化剧烈,但存在小区域范围内(100～200km)的一致性,与地表出露岩石的对比表明:形成渤海湾盆地的新生代伸展作用在下地壳深度有明显的响应,从地震学上获得的泊松比分布对于了解该地区地壳物质组成可起到很好的约束作用.
The Poisson＇ s ratio, an important parameter to understand the interior of the earth, can be dertermined from the ratio of P- to S- seismic wave velocity. Teleseismic P waveform contains much information about the Ps converted wave and its multiples from discontinuities in the crust and the mantle, which can be used to acquire the average thickness and the Poisson＇ s ratio of the crust by the H-k stacking method. Data from 68 broadband seismic stations located in the northwestern basin-mountain boundary of the Bohai Bay Basin are processed, and the distributions of the average crustal thickness and Poisson＇ s ratios are determined. We find that there is a distinct differentiation of Poisson＇ s ratios in the study area. The distribution of Poisson＇ s ratios on the flank of the mountain is rather uniform, while on the flank of the basin much variable. The comparison between Poisson＇s ratios and the surface geology manifests that there is an apparent response in the lower crust to the intense extension of the Bohai Bay Basin during Cenozoic. The Poisson＇ s ratios deduced from seismology can be used to constrain the compostion of the crust in the study area.
出处
《地球物理学报》
SCIE
EI
CAS
CSCD
北大核心
2005年第5期1077-1084,共8页
Chinese Journal of Geophysics
基金
国家自然科学基金重点项目(40434012)
国家自然科学基金(40234038)资助.
关键词
泊松比
地壳厚度
接收函数
渤海湾盆地
Poisson＇s ratios, Crustal thickness, Receiver function, the Bohai Bay Basin
