ACCOMMODATING LATERAL VELOCITY CHANGES IN KIRCHHOFF MIGRATION BY MEANS OF FERMAT'S PRINCIPLE

When velocity varies laterally as well as with depth, an exact Kirchhoff depth migration requires that rays be traced from each depth point in the section to each source/receiver location. Because such a procedure is prohibitively expensive, Kirchhoff migration is usually carried out by using a velocity function that depends only on depth. This paper introduces a new method, based on Fermat's principle, which is a compromise between these two extremes. The slowness (reciprocal volocity) function is written as the sum of two functions, the first of which is large and depends only on depth, while the other is small and varies both with depth and position along the line. Raypaths are traced for the first slowness function and are used to calculate migration curves. For each depth point these same raypaths are used to calculate traveltime perturbations due to the laterally varying part of the slowness. The traveltime perturbations are added to the migration curve to obtain an approximation to the exact migration curve.

• Availability:
  • Find a library where document is available. Order URL: http://worldcat.org/issn/00963941
• Corporate Authors:

  American Geophysical Union

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  Washington, DC  United States  20009-1277
• Authors:
  • Carter, J A
• Publication Date: 1983-12-13

Media Info

• Pagination: p. 984
• Serial:
  • EOS Transactions
  • Volume: 64
  • Issue Number: 50
  • Publisher: American Geophysical Union
  • ISSN: 0096-3941

Subject/Index Terms

• TRT Terms: Depth; Elastic waves; Seismicity; Velocity
• Uncontrolled Terms: Change; Seismic investigations
• Old TRIS Terms: Lateral movement
• Subject Areas: Geotechnology; Highways; I41: General Soil Surveys;

Filing Info

• Accession Number: 00381248
• Record Type: Publication
• Files: TRIS
• Created Date: Mar 30 1984 12:00AM