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Title: Methods for the robust computation of the long-period seismic spectrum of broad-band arrays

Abstract

SUMMARY We describe array methods to search for low signal-to-noise ratio (SNR) signals in long-period seismic data using Fourier analysis. This is motivated by published results that find evidence of solar free oscillations in the Earth's seismic hum. Previous work used data from only one station. In this paper, we describe methods for computing spectra from array data. Arrays reduce noise level through averaging and provide redundancy that we use to distinguish coherent signal from a random background. We describe two algorithms for calculating a robust spectrum from seismic arrays, an algorithm that automatically removes impulsive transient signals from data, a jackknife method for estimating the variance of the spectrum, and a method for assessing the significance of an entire spectral band. We show examples of their application to data recorded by the Homestake Mine 3-D array in Lead, SD and the Piñon Flats PY array. These are two of the quietest small aperture arrays ever deployed in North America. The underground Homestake data has exceptionally low noise, and the borehole sensors of the PY array also have very low noise, making these arrays well suited to finding very weak signals. We find that our methods remove transient signals effectivelymore » from the data so that even low-SNR signals in the seismic background can be found and tested. Additionally, we find that the jackknife variance estimate is comparable to the noise floor, and we present initial evidence for solar g-modes in our data through the T2 test, a multivariate generalization of Student's t-test.« less

Authors:
ORCiD logo [1]; ORCiD logo [1];  [2];  [3]
  1. Department of Earth and Atmospheric Sciences, Indiana University, Bloomington, IN 47405, USA
  2. Department of Mathematics and Statistics, Queens University, Kingston, Ontario K7L 3N5, Canada
  3. IGPP, Scripps Institute of Oceanography, University of California at San Diego, La Jolla, CA 92093, USA
Publication Date:
Sponsoring Org.:
USDOE National Nuclear Security Administration (NNSA)
OSTI Identifier:
1633473
Resource Type:
Published Article
Journal Name:
Geophysical Journal International
Additional Journal Information:
Journal Name: Geophysical Journal International Journal Volume: 222 Journal Issue: 3; Journal ID: ISSN 0956-540X
Publisher:
Oxford University Press
Country of Publication:
United Kingdom
Language:
English

Citation Formats

Caton, Ross C., Pavlis, Gary L., Thomson, David J., and Vernon, III, Frank L. Methods for the robust computation of the long-period seismic spectrum of broad-band arrays. United Kingdom: N. p., 2020. Web. doi:10.1093/gji/ggaa218.
Caton, Ross C., Pavlis, Gary L., Thomson, David J., & Vernon, III, Frank L. Methods for the robust computation of the long-period seismic spectrum of broad-band arrays. United Kingdom. doi:https://doi.org/10.1093/gji/ggaa218
Caton, Ross C., Pavlis, Gary L., Thomson, David J., and Vernon, III, Frank L. Wed . "Methods for the robust computation of the long-period seismic spectrum of broad-band arrays". United Kingdom. doi:https://doi.org/10.1093/gji/ggaa218.
@article{osti_1633473,
title = {Methods for the robust computation of the long-period seismic spectrum of broad-band arrays},
author = {Caton, Ross C. and Pavlis, Gary L. and Thomson, David J. and Vernon, III, Frank L.},
abstractNote = {SUMMARY We describe array methods to search for low signal-to-noise ratio (SNR) signals in long-period seismic data using Fourier analysis. This is motivated by published results that find evidence of solar free oscillations in the Earth's seismic hum. Previous work used data from only one station. In this paper, we describe methods for computing spectra from array data. Arrays reduce noise level through averaging and provide redundancy that we use to distinguish coherent signal from a random background. We describe two algorithms for calculating a robust spectrum from seismic arrays, an algorithm that automatically removes impulsive transient signals from data, a jackknife method for estimating the variance of the spectrum, and a method for assessing the significance of an entire spectral band. We show examples of their application to data recorded by the Homestake Mine 3-D array in Lead, SD and the Piñon Flats PY array. These are two of the quietest small aperture arrays ever deployed in North America. The underground Homestake data has exceptionally low noise, and the borehole sensors of the PY array also have very low noise, making these arrays well suited to finding very weak signals. We find that our methods remove transient signals effectively from the data so that even low-SNR signals in the seismic background can be found and tested. Additionally, we find that the jackknife variance estimate is comparable to the noise floor, and we present initial evidence for solar g-modes in our data through the T2 test, a multivariate generalization of Student's t-test.},
doi = {10.1093/gji/ggaa218},
journal = {Geophysical Journal International},
number = 3,
volume = 222,
place = {United Kingdom},
year = {2020},
month = {5}
}

Journal Article:
Free Publicly Available Full Text
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DOI: https://doi.org/10.1093/gji/ggaa218

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