Three-Station Interferometry and Tomography: Coda vs. Direct Waves

This is a Preprint and has not been peer reviewed. The published version of this Preprint is available: https://doi.org/10.1093/gji/ggaa046.

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Authors

Shane Zhang , Lili Feng, Michael H. Ritzwoller

Abstract

Traditional two-station ambient noise interferometry estimates the Greens function between a pair of synchronously deployed seismic stations. Three-station interferometry considers records observed three stations at a time, where two of the stations are considered receiver-stations and the third is a source-station. Cross-correlations between records at the source-station with each of the receiver-stations are correlated or convolved again to estimate the Greens function between the receiver-stations, which may be deployed asynchronously. We use data from the EarthScope USArray in the western US to compare Rayleigh wave dispersion obtained from two-station and three-station interferometry. Three three-station interferometric methods are distinguished by the data segment utilized (coda-wave or direct-wave) and whether the source-stations are constrained to lie in stationary phase zones approximately inline with the receiver-stations. The primary finding is that the three-station direct wave methods perform considerably better than the three-station coda-wave method and two-station ambient noise interferometry for obtaining surface wave dispersion measurements in terms of signal-to-noise ratio, bandwidth, and the number of measurements obtained, but possess small biases relative to two-station interferometry. We present a ray-theoretic correction method that largely removes the bias below 40~s period and reduces it at longer periods. Three-station direct-wave interferometry provides substantial value for imaging the crust and uppermost mantle, and its ability to bridge asynchronously deployed stations may impact the design of seismic networks in the future.

DOI

https://doi.org/10.31223/osf.io/6gw27

Subjects

Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics

Keywords

seismic noise, Coda waves, Seismic interferometry, Seismic tomography, Structure of the Earth, Surface waves and free oscillations

Dates

Published: 2020-08-16 19:49

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License

CC BY Attribution 4.0 International

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