Seismic borehole tomography - Theory and computational methods

Journal Article · Sat Feb 01 04:00:00 EST 1986 · Proc. IEEE; (United States)

OSTI ID:5613232

Ivansson, S

Tomographic inversion can be applied to seismic travel time data to obtain a map of seismic velocities in a rock volume, although the field geometries will not, in general, allow a complete ray sampling. This paper deals with theoretical and computational aspects of tomographic inversion under such circumstances. It is shown that some usual measurement geometries could, in theory, be sufficient for determining the seismic velocity distribution uniquely (under the straight-ray approximation). From the computational point of view, however, the inverse problem can be poorly conditioned. The usual transform methods of reconstruction, developed for medical tomography, are not applicable. A brief discussion is, therefore, given of a few relevant geophysical inverse techniques and the CG-algorithm applied to a certain quadratic functional is shown to give reasonable images. A convergence result that contains ''ART with smoothing'' as a special case is also obtained. Techniques to correct for ray bending are discussed.

• Research Organization: FOA (National Defense Res. Inst.), Div. 29, S-102 54 Stockholm
• OSTI ID: 5613232
• Journal Information: Proc. IEEE; (United States), Journal Name: Proc. IEEE; (United States) Vol. 74:2; ISSN IEEPA
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
580203* -- Geophysics-- Geophysical Survey Methods-- (1980-1989)
ALGORITHMS
BOREHOLES
CALCULATION METHODS
CAVITIES
COMPUTER CALCULATIONS
COMPUTERIZED TOMOGRAPHY
DIAGNOSTIC TECHNIQUES
GEOMETRY
GEOPHYSICAL SURVEYS
GEOPHYSICS
IMAGE PROCESSING
IMAGES
MATHEMATICAL LOGIC
MATHEMATICS
MECHANICS
PHASE VELOCITY
PROCESSING
ROCK MECHANICS
ROCKS
SEISMIC SURVEYS
SEISMIC WAVES
SURVEYS
TIME MEASUREMENT
TOMOGRAPHY
VELOCITY