| 摘要: |
| 地学长江计划安徽段实验是大容量气枪震源在长江的首次激发。本文对布设在气枪固定激发点附近的流动台和周边固定台接收到的气枪信号进行线性叠加，以分析近场、远场信号的时频特性，并利用叠加结果检测气枪信号的传播特性，分析不同环境因素对信号传播距离的影响。结果表明：①近岸首台可以接收到清晰的压力脉冲、气泡脉冲的体波和面波信号；②气枪信号主频为5Hz左右，随着震中距的增加，压力脉冲信号衰减很快，信号主频频带变窄；③对信号传播距离进行初步检测发现，最近的传播距离为180km，最远共有3个激发点传播达到260km，夜晚激发时信号传播距离较远。 |
| 关键词: 大容量气枪 定点激发 时频分析 信号检测 |
| DOI： |
| 分类号: |
| 基金项目:中国地震局公益性行业科研专项(2015419015)、国家自然科学基金(41474071)联合资助 |
|
| Signal detection of large volume airgun source excitation in the fixed field of the Yangtse River |
|
Xu Jiajun1) Cai Huiteng1) Jin Xing1,2,3) Wang Shanxiong1) Xia Ji2,3) Li Pei1)
|
|
1)Earthquake Administration of Fujian Province，Fuzhou 35000，China；2)Institute of Engineering Mechanics，CEA，Harbin 150080，China；3)Key Laboratory of Earthquake Engineering and Engineering Vibration，CEA，Harbin 150080，China
|
| Abstract: |
| It is the first time for large volume air-gun excited in the Yangtse River，so it is necessary to study the time-frequency characteristic based on the linear stacked seismic data from records from temporary stations near the fixed fields and seismic stations. Air-gun signal propagation distances were detected using the stacked seismic data to analyze the environmental impact on signal propagation distance. The results showed that：(1)the air-gun signal produced by bubble pulses，pressure pulses and surface wave can be received by the temporary station near by fixed field；(2)the dominant frequency of bubble at 5Hz or so can be received by both near-field stations and far-field stations，pressure pulses rapidly weakens and the dominant frequency bands get narrower as epicentral distance increases；(3)the longest spread distance of signal is 260km，the nearest is 180km，and the signal can travel further in evening. |
| Key words: Large volume airgun Excited in fixed field Timefrequency characteristics Signal detection |
