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Article
A Comparison of Methods to Estimate Seismic Phase Delays: Numerical Examples for Coda Wave Interferometry
Geophysical Journal International (2015)
  • T. Dylan Mikesell, Boise State University
  • Alison E. Malcolm, Massachusetts Institute of Technology
  • Di Yang, Massachusetts Institute of Technology
  • Matthew M. Haney
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 compare all three methods 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 good 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.
Keywords
  • time-series analysis,
  • interferometry,
  • seismic monitoring and test-ban treaty verification,
  • coda waves
Publication Date
July, 2015
DOI
10.1093/gji/ggv138
Citation Information
T. Dylan Mikesell, Alison E. Malcolm, Di Yang and Matthew M. Haney. "A Comparison of Methods to Estimate Seismic Phase Delays: Numerical Examples for Coda Wave Interferometry" Geophysical Journal International Vol. 202 Iss. 1 (2015) p. 347 - 360
Available at: http://works.bepress.com/dylan_mikesell/24/