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On noise reduction in vertical seismic records below 2 mHz using local barometric pressure
Author(s) -
Zürn W.,
Widmer R.
Publication year - 1995
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/95gl03369
Subject(s) - quiet , noise (video) , geology , seismic noise , low frequency , atmospheric pressure , noise reduction , infrasound , signal (programming language) , frequency band , ambient noise level , noise measurement , geodesy , noise floor , reduction (mathematics) , atmospheric noise , acoustics , seismology , physics , telecommunications , computer science , mathematics , artificial intelligence , image (mathematics) , oceanography , bandwidth (computing) , geometry , quantum mechanics , programming language , sound (geography) , astronomy
We propose a simple method for the reduction of noise in vertical seismic recordings at frequencies below 2 mHz . The method consists in subtracting the locally recorded, scaled, atmospheric pressure signal from the gravity record. The scale factor is frequency independent and can be linearly estimated from the data. While such a pressure correction was previously only used in the analysis of tidal records, it is equally efficient at the low‐frequency end of the normal mode band and we use gravity recordings of the big 1994 Shikotan and Bolivian quakes to demonstrate this point. Our examples also show that this correction permits to achieve noise levels well below the New Low Noise Model (NLNM) [ Peterson , 1993]. The success of the correction also sheds some light on the physical processes responsible for the generation of low‐frequency seismic noise at quiet observatories.