Wavelet filtering of tube and surface waves

Gerard Schuster*, Yonghe Sun

*Corresponding author for this work

Research output: Contribution to conferencePaperpeer-review

15 Scopus citations

Abstract

We apply a B4 wavelet (the wavelet associated with the cubic splines) filtering algorithm to eliminate tube waves in crosshole seismic data and air-waves+surface waves in CDP data. The coherent noise events are first time-shifted in time to be aligned with one another from trace to trace. For each time sample, the shifted data is wavelet transformed along the trace index coordinate to give the B4 wavelet expansion coefficients. It is recognized that tube or surface wave events are almost stationary from trace to trace so that they mostly contribute to the lowest resolution wavelet coefficients (i.e., lowest frequency components), while the other events contribute to the higher resolution wavelet coefficients (i.e., high frequency components). We simply eliminate the low resolution coefficients and reconstruct the signal from the higher resolution coefficients. Limited numerical tests suggest that wavelet filtering of tube waves are superior to filtering by a median filter. In particular, distortion of non-tube wave events by wavelet filtering is much less pronounced than by median-filtering. Also, the choice of the wavelet cut-off level is trivial compared to the variety of parameter choices in median filtering (e.g., the number of points in the median filter, the bandwidth of the bandpass filter applied after the median filter). Filtering of surface waves in CDP data by wavelet filtering also shows promise.

Original languageEnglish (US)
Pages25-28
Number of pages4
StatePublished - Jan 1 1993
Event1993 Society of Exploration Geophysicists Annual Meeting - Washington, United States
Duration: Sep 26 1993Sep 30 1993

Conference

Conference1993 Society of Exploration Geophysicists Annual Meeting
CountryUnited States
CityWashington
Period09/26/9309/30/93

ASJC Scopus subject areas

  • Geophysics

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