呼图壁气枪数据中面波振幅变化研究*

(1.中国科学技术大学 地球和空间科学学院地震与地球内部物理实验室,安徽 合肥 230026; 2.中国科学技术大学 蒙城地球物理国家野外科学观测研究站,安徽 蒙城 233527)

呼图壁气枪源; 面波振幅; 小波传播子; 到时延迟; 地震波形

Temporal Variations of Surface Wave Amplitude in the Data Collected from Hutubi,Xinjiang Airgun Experiment
YU Wen1,2,YANG Hsin-ying1,2,YU Jing1,2,SUN Daoyuan1,2

(1.Laboratory of Seismology and Physics of Earth's Interior,School of Earth and Space Sciences,University of Science and Technology of China,Hefei 230026,Anhui,China)(2.National Geophysical Observatory at Mengcheng,University of Science and Technology of China,Mengcheng 233527,Anhui,China)

Hutubi airgun; surface wave amplitude; wavelet propagator method; travel time delay; seismic waveform

备注

利用新疆呼图壁气枪数据,在引入小波传播子方法测量到时延迟的基础上,进一步引入面波振幅作为监测地下介质变化的一个重要参数。结果 表明:相对于到时的突跳,面波振幅能克服气枪源震源强度突变带来的测量不稳定; 同时,通过面波到时延迟和振幅变化特征的模拟,发现面波振幅和到时延迟测量存在较好的正相关关系,且可以用介质速度变化所导致的聚焦和散焦效应来解释。面波振幅也可以作为较为稳定的参数来衡量地下介质的波速变化。

In this paper,based on the data collected from Hutubi,Xinjiang Airgun Experiment,we adopted a newly developed wavelet propagator method to measure travel time shift between two waveforms.In addition,we introduced the surface wave amplitude as a new parameter to monitor the change of subsurface velocity.The results show that the relative surface wave amplitude could be an effective parameter,which is less sensitive to abrupt changes of the airgun source energy. to monitor the temporal variations of the subsurface velocity structure.We also observed a positive correlation between relative amplitude ratios and travel time delay,indicating focusing/defocusing effects accompanied by changes in velocity structure.In conclusion,the amplitude of surface wave can also be used as a stable parameter to measure the change of surface velocity.