On the Dispersive Characteristics of Shallow Water Seismic Waves Excited by Air Gun Sound Source in Shallow Water

气枪声源激发的浅海地震波频散特性研究

¹ College of Naval Architecture and Ocean Engineering, Naval University of Engineering, Wuhan 430033, China
² College of Electronic Engineering, Naval University of Engineering, Wuhan 430033, China
³ Navy Staff Office of Southern Theater Command, Zhanjiang 524000, China

Received: 2 September 2018

Abstract

In order to study the dispersion characteristics of seabed seismic waves excited by acoustic sources in shallow water, the sound field at liquid-solid interface is derived based on the wave equation firstly, which results demonstrate that the longitudinal wave and transversal wave are not dispersive, while the Scholte wave is normal dispersive. Then, the numerical simulation is carried out on the sound field at the liquid-solid interface excited by the air gun sound source based on high-order staggered grid finite difference method, which results demonstrate that the dispersion phenomenon of Scholte waves is observed and the theoretical analysis results were verified. Finally, the data of experiment in the sea are analyzed based on the transformation, and the dispersion curve of Scholte wave is finely extracted.

摘要

为了研究由浅海中声源激发的海底地震波主要波动成分的频散特性，首先基于波动方程对液-固界面处的声场进行了推导，证明纵波和横波不具有频散特性，而表面波具有正常频散特性。随后基于高阶交错网格有限差分法，对气枪声源激发的液-固界面处的声场进行了数值仿真，通过分析仿真数据观察到表面波的频散现象，验证了理论分析结果；最后基于τ-p变换对海试数据处理与分析，精细提取了海底表面波的频散曲线。