Characteristics of Low-Frequency Horizontal Noise of Ocean-Bottom Seismic Data

Chao An1,2; Chen Cai3,4; Lei Zhou4,5; Ting Yang6

2021-09-01

10.1785/0220200349

SEISMOLOGICAL RESEARCH LETTERS   影响因子和分区

0895-0695

1938-2057

Horizontal records of ocean-bottom seismographs are usually noisy at low frequencies (< 0.1 Hz). The noise source is believed to be associated with ocean-bottom currents that may tilt the instrument. Currently horizontal records are mainly used to remove the coherent noise in vertical records, and there has been little literature that quantitatively discusses the mechanism and characteristics of low-frequency horizontal noise. In this article, we analyze in situ ocean-bottom measurements by rotating the data horizontally and evaluating the coherency between different channels. Results suggest that the horizontal noise consists of two components, random noise and principle noise whose direction barely changes in time. The amplitude and the direction of the latter are possibly related to the intensity and direction of ocean-bottom currents. Rotating the horizontal records to the direction of the principle noise can largely suppress the principle noise in the orthogonal horizontal channel. In addition, the horizontal noise is incoherent with pressure, indicating that the noise source is not ocean surface water waves (infragravity waves). At some stations in shallow waters (< 300 m), horizontal noise around 0.07 Hz is found to be linearly proportional to the temporal derivative of pressure, which is explained by forces of added mass due to infragravity waves.

SCI ; EI

英语

其他

National Nature Science Foundation of China[U1901602] ; Oceanic Interdisciplinary Program of Shanghai Jiao Tong University["SL2020PT205","SL2020MS005"] ; Shanghai Sheshan National Geophysical Observatory Open Project Grant[2020K01] ; Innovation Group Project of Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai)[311020004] ; Shenzhen Science and Technology Innovation Commission["JCYJ20180504170422082","GJHZ20170313101107497","KQTD20170810111725321"]

Geochemistry & Geophysics

Geochemistry & Geophysics

WOS:000734319200003

SEISMOLOGICAL SOC AMER

20221211815133

Ocean currents ; Seismology ; Surface waters ; Water waves

Surface Water:444.1 ; Seawater, Tides and Waves:471.4 ; Earthquake Measurements and Analysis:484.1 ; Gravitation, Relativity and String Theory:931.5

GEOSCIENCES

人工提交

1.Key Laboratory of Hydrodynamics (Ministry of Education), School of Naval Architecture, Ocean and Civil Engineering, Shanghai Jiao Tong University, Shanghai, China
2.Shanghai Sheshan National Geophysical Observatory, Shanghai, China
3.Guangdong Provincial Key Laboratory of Geodynamics and Geohazards, School of Earth Sciences and Engineering, Sun Yat-sen University, Guangzhou, China
4.Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai, China, https://orcid.org/0000-0002-0433-3991 (LZ)
5.School of Oceanography, Shanghai Jiao Tong University, Shanghai, China
6.OBS Lab, Department of Ocean Science and Engineering, Southern University of Science and Technology, Shenzhen, China, https://orcid.org/0000-0002-3433-0898 (TY)

Chao An,Chen Cai,Lei Zhou,et al. Characteristics of Low-Frequency Horizontal Noise of Ocean-Bottom Seismic Data[J]. SEISMOLOGICAL RESEARCH LETTERS,2021,93(1):257-267.

Chao An,Chen Cai,Lei Zhou,&Ting Yang.(2021).Characteristics of Low-Frequency Horizontal Noise of Ocean-Bottom Seismic Data.SEISMOLOGICAL RESEARCH LETTERS,93(1),257-267.

Chao An,et al."Characteristics of Low-Frequency Horizontal Noise of Ocean-Bottom Seismic Data".SEISMOLOGICAL RESEARCH LETTERS 93.1(2021):257-267.