A comparison of methods to estimate seismic phase delays--Numerical examples for coda wave interferometry
Geophysical Journal International
By: T. Dylan Mikesell, Alison E. Malcolm, Di Yang, and Matthew M. Haney
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Abstract
Time-shift estimation between arrivals in two seismic traces before and after a velocity perturbation is a crucial step in many seismic methods. The accuracy of the estimated velocity perturbation location and amplitude depend on this time shift. Windowed cross correlation and trace stretching are two techniques commonly used to estimate local time shifts in seismic signals. In the work presented here, we implement Dynamic Time Warping (DTW) to estimate the warping function – a vector of local time shifts that globally minimizes the misfit between two seismic traces. We illustrate the differences of all three methods compared to one another using acoustic numerical experiments. We show that DTW is comparable to or better than the other two methods when the velocity perturbation is homogeneous and the signal-to-noise ratio is high. When the signal-to-noise ratio is low, we find that DTW and windowed cross correlation are more accurate than the stretching method. Finally, we show that the DTW algorithm has better time resolution when identifying small differences in the seismic traces for a model with an isolated velocity perturbation. These results impact current methods that utilize not only time shifts between (multiply) scattered waves, but also amplitude and decoherence measurements. DTW is a new tool that may find new applications in seismology and other geophysical methods (e.g., as a waveform inversion misfit function).
Suggested Citation
Mikesell, T.D., Malcolm, A.E., Yang, D., and Haney, M., 2015, A comparison of methods to estimate seismic phase delays--Numerical examples for coda wave interferometry: Geophysical Journal International, v. 202, no. 1, p. 347-360, https://doi.org/10.1093/gji/ggv138.
| Publication type | Article |
|---|---|
| Publication Subtype | Journal Article |
| Title | A comparison of methods to estimate seismic phase delays--Numerical examples for coda wave interferometry |
| Series title | Geophysical Journal International |
| DOI | 10.1093/gji/ggv138 |
| Volume | 202 |
| Issue | 1 |
| Publication Date | April 30, 2015 |
| Year Published | 2015 |
| Language | English |
| Publisher | Oxford University Press on behalf of The Royal Astronomical Society |
| Contributing office(s) | Volcano Science Center |
| Description | 13 p. |
| First page | 347 |
| Last page | 360 |