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MCS data processing for the interpretation of ancient ice sheet movements
- Source: Near Surface Geophysics, Volume 1, Issue 2, Nov 2003, p. 87 - 93
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- 01 Feb 2002
- 01 Nov 2002
- 01 Nov 2002
Abstract
The paper deals with the analysis and reprocessing of data from a 30‐km section of the IT88A‐01 seismic line acquired in the Ross Sea Basin during the Italian 1988 PNRA project (National Program for Antarctic Research). The purpose of this study was to achieve an improved data quality for a better geophysical and geological interpretation of the area. Field data were subjected to a processing sequence aimed at enhancing the S/N ratio and at recovering reliable acoustic impedances. Acoustic impedance recovery calls for the estimation of both the velocity field and the pseudo‐acoustic impedance in the wavelet frequency band. At the end of the study, a time‐migrated stack section and a time impedance map were produced. The migrated section shows, quite clearly, an event previously hidden by a strong sea‐bottom multiple; furthermore reflections that can be related to proximal debris left by ice expansion and regression are now visible. The impedance map shows impedance inversion along the whole length of the processed section, possibly denoting different sedimentary conditions due to ice‐sheet loading and unloading in the Ross Sea.
The processing sequence described and the recovery of the absolute acoustic impedance as outlined here could be adopted to determine, by means of seismic reflection, the position and movement of the ice sheet in the remote past.