Polarisation analysis: What is it? Why do you need it? How do you do it?

Hendrick, Natasha and Hearn, Steve J. (1999) Polarisation analysis: What is it? Why do you need it? How do you do it?. Exploration Geophysics, 30 3 & 4: 177-190. doi:10.1071/EG999177

Author Hendrick, Natasha
Hearn, Steve J.
Title Polarisation analysis: What is it? Why do you need it? How do you do it?
Journal name Exploration Geophysics   Check publisher's open access policy
ISSN 0812-3985
Publication date 1999
Sub-type Article (original research)
DOI 10.1071/EG999177
Volume 30
Issue 3 & 4
Start page 177
End page 190
Total pages 14
Editor J. Denham
Place of publication Melbourne, VIC, Australia
Publisher CSIRO Publishing
Collection year 1999
Language eng
Subject C1
260205 Explosion Seismology
650100 Exploration
Formatted abstract
Polarisation analysis quantitatively describes the particle motion of a seismic wavefield. It is the fundamental vector processing technique applied to multi-component seismic data. Synthetic and real VSP examples illustrate the application of polarisation analysis via particle-motion hodograms, and an automated single-trace time-domain method.

Polarisation analysis can facilitate the extraction of pure P and S-wave sections, removal of unwanted noise events, and recovery of information relating to fracturing, porosity and lithology from multi-component data. Two applications of polarisation analysis are demonstrated, namely the extraction of pure P and S-wave sections, and S-wave splitting analysis.

The success of polarisation analysis depends on the accuracy with which the recorded seismic wavefield represents the truevector wavefield. Care must be taken to ensure particle motion is not distorted during acquisition and preprocessing. Sensor response and coupling must be matched across components. Amplitude equalisation must be identical on all components. Frequency and/or velocity filtering should be designed to remove only noise, so as not to modify the underlying signal.

The effect of the analysis window length is demonstrated, with the best compromise between resolution and stability being provided by a window approximately equal to the dominant period of the recorded signal. If more than one seismic event exists within the analysis window, single-trace polarisation analysis cannot accurately recover information on the individual wave types. A comparison of polarisation analysis in the t-x and τ-p domains highlights the value of utilising both slowness and polarisation information to enhance the accuracy of discriminating between interfering wave types.
Q-Index Code C1
Additional Notes Paper presented at 13th ASEG Conference and Exhibition, Hobart, November 1998.

Document type: Journal Article
Sub-type: Article (original research)
Collection: School of Physical Sciences Publications
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Created: Tue, 10 Jun 2008, 13:48:15 EST