Autocorrelation Infrasound Interferometry

Hugo D. Ortiz, Robin S. Matoza, Jeffrey B. Johnson, Stephen Hernandez, Juan C. Anzieta, Mario C. Ruiz

Research output: Contribution to journalArticlepeer-review

12 Scopus citations

Abstract

Seismic and infrasound multistation ambient-noise interferometry has been widely used to infer ground and atmospheric properties, and single-station and autocorrelation seismic interferometry has also shown potential for characterizing Earth structure at multiple scales. We extend autocorrelation seismic interferometry to ambient atmospheric infrasound recordings that contain persistent local noise from waterfalls and rivers. Across a range of geographic settings, we retrieve relative sound-speed changes that exhibit clear diurnal oscillations consistent with temperature and wind variations. We estimate ambient air temperatures from variations in relative sound speeds. The frequency band from 1 to 2 Hz appears most suitable to retrieve weather parameters as nearby waterfalls and rivers may act as continuous and vigorous sources of infrasound that help achieve convergence of coherent phases in the autocorrelation codas. This frequency band is also appropriate for local sound-speed variations because it has infrasound with wavelengths of ∼170–340 m, corresponding to a typical atmospheric boundary layer height. After applying array analysis to autocorrelation functions derived from a three-element infrasound array, we find that autocorrelation codas are composed of waves reflected off nearby topographic features, such as caldera walls. Lastly, we demonstrate that autocorrelation infrasound interferometry offers the potential to study the atmosphere over at least several months and with a fine time resolution.

Original languageAmerican English
Article numbere2020JB020513
JournalJournal of Geophysical Research: Solid Earth
Volume126
Issue number4
DOIs
StatePublished - Apr 2021

Keywords

  • autocorrelations
  • infrasonic thermometer
  • infrasound
  • interferometry
  • noise
  • volcano infrasound

EGS Disciplines

  • Earth Sciences
  • Geophysics and Seismology

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