Large-explosive source, wide-recording aperture, seismic profiling on the Columbia Plateau, Washington

Geophysics
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Abstract

Clear subsurface seismic images have been obtained at low cost on the Columbia Plateau, Washington. The Columbia Plateau is perhaps the most notorious of all 'bad-data' areas because large impedance contrasts in surface flood basalts severely degrade the seismic wavefield. This degradation was mitigated in this study via a large-explosive source, wide-recording aperture shooting method.The shooting method emphasizes the wide-angle portion of the wavefield, where Fermat's principle guarantees reverberation will not interfere with the seismic manifestations of crucial geologic interfaces. The basalt diving wave, normally discarded in standard common midpoint (CMP) seismic profiling, can be used to image basalt velocity structure via traveltime inversion. Maximum depth-penetration of the diving wave tightly constrains basalt-sediment interface depth. An arrival observed only at shot-receiver offsets greater than 15 km can be used to determine the velocity and geometry of basement via simultaneous inversion.The results from this study suggest that previous geologic hypotheses and hydrocarbon play concepts for the Columbia Plateau may have been in error.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Large-explosive source, wide-recording aperture, seismic profiling on the Columbia Plateau, Washington
Series title Geophysics
DOI 10.1190/1.1443588
Volume 59
Issue 2
Year Published 1994
Language English
Publisher Society of Exploration Geophysicists
Description 13 p.
First page 259
Last page 271
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