In Design of an Ocean Bottom Seismometer Sensor: Minimize Vibration Experienced by Underwater Low-Frequency Noise

Xiaohan Wang; Shangchun Piao; Yahui Lei; Nansong Li

doi:10.3390/s18103446

In Design of an Ocean Bottom Seismometer Sensor: Minimize Vibration Experienced by Underwater Low-Frequency Noise

Sensors (Basel). 2018 Oct 13;18(10):3446. doi: 10.3390/s18103446.

Authors

Xiaohan Wang^{1

2

3}, Shangchun Piao^{4

5

6}, Yahui Lei^{7

8

9}, Nansong Li^{10

11

12}

Affiliations

¹ Acoustic Science and Technology Laboratory, Harbin Engineering University, Harbin 150001, China. wangxiaohan@hrbeu.edu.cn.
² Key Laboratory of Marine Information Acquisition and Security, Harbin Engineering University, Ministry of Industry and Information Technology, Harbin 150001, China. wangxiaohan@hrbeu.edu.cn.
³ College of Underwater Acoustic Engineering, Harbin Engineering University, Harbin 150001, China. wangxiaohan@hrbeu.edu.cn.
⁴ Acoustic Science and Technology Laboratory, Harbin Engineering University, Harbin 150001, China. piaoshengchun@hrbeu.edu.cn.
⁵ Key Laboratory of Marine Information Acquisition and Security, Harbin Engineering University, Ministry of Industry and Information Technology, Harbin 150001, China. piaoshengchun@hrbeu.edu.cn.
⁶ College of Underwater Acoustic Engineering, Harbin Engineering University, Harbin 150001, China. piaoshengchun@hrbeu.edu.cn.
⁷ Acoustic Science and Technology Laboratory, Harbin Engineering University, Harbin 150001, China. leiyahui@hrbeu.edu.cn.
⁸ Key Laboratory of Marine Information Acquisition and Security, Harbin Engineering University, Ministry of Industry and Information Technology, Harbin 150001, China. leiyahui@hrbeu.edu.cn.
⁹ College of Underwater Acoustic Engineering, Harbin Engineering University, Harbin 150001, China. leiyahui@hrbeu.edu.cn.
¹⁰ Acoustic Science and Technology Laboratory, Harbin Engineering University, Harbin 150001, China. linansong@hrbeu.edu.cn.
¹¹ Key Laboratory of Marine Information Acquisition and Security, Harbin Engineering University, Ministry of Industry and Information Technology, Harbin 150001, China. linansong@hrbeu.edu.cn.
¹² College of Underwater Acoustic Engineering, Harbin Engineering University, Harbin 150001, China. linansong@hrbeu.edu.cn.

Abstract

Ocean Bottom Seismometers (OBS) placed on the seafloor surface are utilized for measuring the ocean bottom seismic waves. The vibration of OBS excited by underwater noise on its surface may interfere with its measured results of seismic waves. In this particular study, an OBS was placed on the seabed, while ray acoustic theory was used to deduce the sound field distribution around the OBS. Then using this information, the analytical expression for the OBS vibration velocity was obtained in order to find various factors affecting its amplitude. The finite element computing software COMSOL Multiphysics^® (COMSOL) was used to obtain the vibration response model of the OBS which was exposed to underwater noise. The vibration velocity for the OBS calculated by COMSOL agreed with the theoretical result. Moreover, the vibration velocity of OBS with different densities, shapes, and characters were investigated as well. An OBS with hemispherical shape, consistent average density as that of the seafloor, and a physical structure of double tank has displayed minimum amplitude of vibration velocity. The proposed COMSOL model predicted the impact of underwater noise while detecting the ocean bottom seismic waves with the OBS. In addition, it provides significant help for the design and optimization of an appropriate OBS.

Keywords: COMSOL; OBS (Ocean Bottom Seismometer); acoustic waves; vibrational response.