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International Journal of Geophysics
Volume 2011 (2011), Article ID 316581, 8 pages
http://dx.doi.org/10.1155/2011/316581
Research Article

Dynamically Focused Gaussian Beams for Seismic Imaging

Department of Earth and Atmospheric Sciences, Purdue University, West Lafayette, IN 47907, USA

Received 15 January 2011; Accepted 22 March 2011

Academic Editor: Yu Zhang

Copyright © 2011 Robert L. Nowack. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

An initial study is performed in which dynamically focused Gaussian beams are investigated for seismic imaging. Focused Gaussian beams away from the source and receiver plane allow the narrowest and planar portions of the beams to occur at the depth of a specific target structure. To match the seismic data, quadratic phase corrections are required for the local slant stacks of the surface data. To provide additional control of the imaging process, dynamic focusing is investigated where all subsurface points are specified to have the same planar beam fronts. This gives the effect of using nondiffracting beams, but actually results from the use of multiple focusing depths for each Gaussian beam. However, now different local slant stacks must be performed depending on the position of the subsurface scattering point. To speed up the process, slant stacking of the local data windows is varied to match the focusing depths along individual beams when tracked back into the medium. The approach is tested with a simple model of 5-point scatterers which are then imaged with the data, and then to the imaging of a single dynamically focused beam for one shot gather computed from the Sigsbee2A model.