Vp/Vs character of shallow strata, Red Deer, Alberta

Sarah E. Richardson and Don C. Lawton


Acquisition of zero-offset vertical seismic profiles with both a compressional and a shear source allows a detailed examination of the velocities of shallow strata. Good correlation was found between velocity values extracted from seismic data and those extracted from cased hole well logs, with seismic traveltimes being slightly slower as a result of dispersion. Approximately 2.3% dispersion is noted in P-wave data, whereas S-wave data demonstrates approximately 6.8% dispersion. At the study site near Red Deer, Vp/Vs was found to be high (~5) in the near-surface, decreasing to approximately 2.5 at 300 m depth. This Vp/Vs profile matches well with shallow profiles recorded in other areas.

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