源区水位对云南宾川大容量气枪震源子波特性的影响  

Effects of reservoir water level changes on the characteristics of airgun wavelets in Binchuan,Yunnan

作　　者：刘春禹 杨宏峰[2,3] 杨微 王伟涛[1] 杨军[4] 茶文剑 李孝宾 叶泵 LIU ChunYu;YANG HongFeng;YANG Wei;WANG WeiTao;YANG Jun;CHA WenJian;LI XiaoBin;YE Beng(Institute of Geophysics,China Earthquake Administration,Beijing 100081,China;Earth and Environmental Sciences Programme,The Chinese University of Hong Kong,Hong Kong,China;Shenzhen Research Institute,The Chinese University of Hong Kong,Shenzhen Guangdong 518057,China;Dali Center,China Seismic Experimental Site,China Earthquake Administration,Dali Yunnan 671000,China)

机构地区：[1]中国地震局地球物理研究所,北京100081 [2]香港中文大学地球与环境科学系,中国香港 [3]香港中文大学深圳研究院,广东深圳518057 [4]中国地震科学实验场大理中心,云南大理671000

出　　处：《地球物理学报》2024年第11期4160-4170,共11页Chinese Journal of Geophysics

基　　金：国家自然科学基金(41974069);中央公益类科研院所基本科研业务专项(DQJB22K46);香港研究资助局优配研究基金(14306122)共同资助.

摘　　要：近些年来,大容量气枪震源逐渐被用于研究中国大陆地壳结构以及其时变特征,但激发水库的水位不可控,气枪震源子波信号的重复性受到严重影响,研究地壳介质时变特征存在着很大挑战.以往研究环境因素对气枪子波的影响时,假设水体为半无限空间介质,常忽视气枪至水体底部的距离,而陆地有限水体的水位因素不应该被忽略.针对这一问题,本文从经验公式角度解析云南宾川大银甸水库水位变化对气枪子波信号的影响,包括子波主脉冲振幅、优势频率、气泡脉冲优势频率和主脉冲-气泡脉冲振幅比等.研究结果表明4支气枪在激发过程中存在相互作用,显示气泡脉冲优势频率、主脉冲振幅和优势频率与气枪至水库底距离呈正相关关系,主脉冲-气泡脉冲振幅比与气枪至水库底距离呈负相关关系.研究成果可优化有限水体气枪震源激发实验参数,为利用陆地大容量气枪震源开展地下介质时变特征研究奠定基础.A large volume airgun array has been increasingly used to investigate the subsurface structure and to monitor the shallow crustal response in Chinese mainland. However, changes in the water level of the reservoir affect the repeatabilities of airgun wavelets, hindering the monitoring of crustal velocity changes. In previous research on the wavelet characteristics, the water body was usually treated as a half-space model, neglecting the distance from the Airgun to the Bottom of the reservoir (DAB). However, when studying wavelet characteristics of inland airguns, we cannot neglect the effects due to the limited depth of the water body. In this study, we explored the empirical relationship between the DAB and the amplitude and frequency of the primary pulse, the frequency of the bubble pulse, and the amplitude ratio of the primary to the bubble pulse. We found that four airguns interacted with each other. We observed that the maximum amplitude of the primary pulse, the dominant frequency of the primary pulse and bubble pulse had a positive correlation to the DAB. The amplitude ratio of the primary pulse to the bubble pulse had a negative correlation with the DAB. Our results can help adjust the experimental settings and provide a foundation for investigating subsurface velocity changes.

关 键 词：陆地水体 大容量气枪 气枪子波特征 气枪相互作用 气枪子波经验公式 

分 类 号：P315[天文地球—地震学]