胡久鹏^1,,
王伟涛^1,,,
王宝善¹,
陈颙²,
蒋生淼¹
1. 中国地震局地球物理研究所 中国地震局地震观测与地球物理成像重点实验室, 北京 100081
2. 南京大学 地球科学与工程学院, 南京 210023

基金项目: 国家自然科学基金重大项目（41790463），国家自然科学基金（41574052，41674058），地震行业专项（201508008），中央公益类科研院所基本科研业务专项（DQJB16A01）资助


详细信息

作者简介: 胡久鹏, 男, 1987年生, 博士生, 研究方向为气枪主动源.E-mail:snowtree@yeah.net

通讯作者: 王伟涛, E-mail:wangwt@cea-igp.ac.cn

中图分类号: P315

收稿日期:2017-05-29
修回日期:2018-01-17
上线日期:2018-03-05

Calculating the propagation of airgun source in a limited water body using the back-projection method

HU JiuPeng^1,,
WANG WeiTao^1,,,
WANG BaoShan¹,
CHEN Yong²,
JIANG ShengMiao¹
1. Institute of Geophysics, China Earthquake Administration(Seismic Observation and Geophysical Imaging Laboratory), Beijing 100081, China
2. School of Earth Sciences and Engineering, Nanjing University, Nanjing 210023, China


More Information

Corresponding author: WANG WeiTao,E-mail:wangwt@cea-igp.ac.cn

MSC: P315

--> Received Date: 29 May 2017
Revised Date: 17 January 2018
Available Online: 05 March 2018


摘要
摘要:陆地大容量气枪震源可用于区域尺度地球物理结构及变化的勘测.对气枪震源在有限水体内震源过程的研究，有助于我们深入了解气枪信号机制及气枪信号不同震相产生的成因.然而由于有限水体中大容量气枪激发的复杂物理过程，特别是复杂固液界面的存在，目前却没有较好的理论模型用以描述陆地气枪震源信号的能量传播特征.反投影方法是一种计算震源破裂过程的方法，能在动力学参数有限的情况下得到较优的结果.本文以此提出了一种修改的反投影方法，以用于模拟气枪震源激发过程中的能量分布图像.将气枪的激发分解为五个简化的物理过程，并分别建立数值模型，计算每个模型的理论波场，用作新方法的输入数据.通过对五个数值模型的数据计算发现，该方法可以准确地得到气枪激发后水体中的波场形态的变化，能够分辨出气枪激发过程中的气枪激发、气泡上浮、气泡震荡等过程，刻画能量分布特征，并且发现水听器足够密集与合理布置能达到更好的效果.该方法可以为气枪震源的快速评估及气枪震源的有效应用提供参考.
关键词: 反投影/
气枪震源/
有限水体

Abstract:The large volume airgun source can be applied to probing geophysical structure and changes on regional scales. But so far it still lacks of a solid theoretical model to characterize the propagation features of the land air-gun signal due to the complexity of the water-solid boundary. The research on air-gun in a limited land water body can further understanding of the physical mechanism of the airgun and the principle of different earthquake phases distribution. As a method to image earthquake rupture, back-projection can provide qualified results with a few kinetic parameters. We present a modified back-projection method to simulate the energy distribution of the air-gun source located in a land limited water body. We decompose the excitation of airgun into five simplified physical processes, and establish numerical models for each process to calculate its theoretical wave field, which is used as input data of the new method. Numerical calculations show that this new method is able to capture the evolution of the wave field and characterize the distribution of the source energy. We also find that enough reasonably arranged hydrophones can help achieve better results. This method provides a new approach to quickly evaluate the effectiveness of land airgun and to further understanding of the airgun features.
Key words:Back-projection/
Airgun source/
Limited water body



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