Shear wave studies in glacial till

Bradley J. Carr, Z. Hajnal

Research output: Paper

1 Citation (Scopus)

Abstract

In conjunction with an ongoing P-wave seismic reflection program in the near-surface glacial tills near Saskatoon, Saskatchewan, two short multicomponent surface (CDP) lines and two multicomponent Vertical Seismic Profiles (VSPs) were processed for their shear wave responses. The study was undertaken to determine: reflections are identifiable in the glacial tills near Saskatoon, Saskatchewan, 2) if shear wave energy is distinct from 1) if shear wave Raleigh and Love waves in this material, and 3) whether or not shear waves increase the resolution of targets in the near-surface. Both data sets reveal coherent shear wave reflections. In addition, the multicomponent approach provides a better understanding of the nature of the reflectivity within these unconsolidated sediments through the analysis of Vp, Vs and Vp/Vs curves. Shear waves are able to image each of the sand lenses known to exist in the area. In Borehole #3, one sand lens in the L. Floral Formation not only produces a shear wave reflection, but shows a decrease in Vp/Vs ratio (i.e. Vp/Vs = 2.5, when the background is 2.9). This zone corresponds to a large increase seen in the borehole resistivity log, and ~5.0% decrease in estimated porosity. It is assumed that this sand layer is not uniform and may contain more clay than other sand layers within the till sequence. Therefore, the analysis of shear waves, as part of a multicomponent seismic experiment, provides a more complete understanding of the interaction between the seismic wavefield and surrounding lithologies.

Original languageEnglish
Pages869-872
Number of pages4
Publication statusPublished - jan. 1 1996
Event1996 Society of Exploration Geophysicists Annual Meeting - Denver, United States
Duration: nov. 10 1996nov. 15 1996

Other

Other1996 Society of Exploration Geophysicists Annual Meeting
CountryUnited States
CityDenver
Period11/10/9611/15/96

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ASJC Scopus subject areas

  • Geophysics

Cite this

Carr, B. J., & Hajnal, Z. (1996). Shear wave studies in glacial till. 869-872. Paper presented at 1996 Society of Exploration Geophysicists Annual Meeting, Denver, United States.