Volume 37, Issue 3 (May 2014)

    Signal Processing Challenges When Processing DST and CST Seismic Data Containing TIRs

    (Received 14 July 2013; accepted 5 February 2014)

    Published Online: 2014

    CODEN: GTJOAD

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    Abstract

    Downhole Seismic Testing (DST) and Crosshole Seismic Testing (CST) are important geotechnical testing techniques which provide for low strain (<10–5) in situ compression (Vp) and shear (Vs) wave velocity estimates. The Vs and Vp interval velocities are determined by obtaining relative arrival times of source waves as they travel through the stratigraphy and are recorded by one or more vertically (DST) and/or horizontally (CST) offset seismic sensors. The relative arrival times are typically obtained by cross-correlating the recorded source waves or identifying reference features within the seismic trace such as a peak, trough, crossover point, or first break. A very common and yet poorly understood problem encountered in DST and CST is the analysis of seismograms that contain Total Internal Reflections (TIRs). TIRs arise when the incident angle exceeds the critical angle; as a result of which reflection coefficients become complex, which in turn leads to distortions in the reflected source wave. This paper addresses the issue of TIRs and the signal processing challenges when processing seismic data containing TIRs.


    Author Information:

    Baziw, Erick
    Baziw Consulting Engineers Ltd., Vancouver, B.C.

    Verbeek, Gerald
    Baziw Consulting Engineers Ltd., Vancouver, B.C.


    Stock #: GTJ20130122

    ISSN: 0149-6115

    DOI: 10.1520/GTJ20130122

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    Author
    Title Signal Processing Challenges When Processing DST and CST Seismic Data Containing TIRs
    Symposium , 0000-00-00
    Committee D18