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Title: Limitations on near-surface correction for multicomponent offset VSP

Conference ·
OSTI ID:80178
; ;  [1]
  1. British Geological Survey, Edinburgh (United Kingdom)

Multicomponent data are degraded due to near-surface scattering and non-ideal or unexpected source behavior. These effects cannot be neglected when interpreting relative wavefield attributes derived from compressional and shear waves. They confuse analyses based on standard scalar procedures and a prima facia interpretation of the vector wavefield properties. Here, the authors highlight two unique polar matrix decompositions for near-surface correction in offset VSPs, consider their inherent mathematical constraints and how they impact on subsurface interpretation. The first method is applied to a four component subset of a six component field data from a configuration of three concentric rings and walkaway source positions forming offset VSPs in the Cymric field, California. The correction appears successful in automatically converting the wavefield into its ideal form, and the qSl polarizations scatter around N15{degree}E in agreement with the layer stripping of Winterstein and Meadows (1991).

OSTI ID:
80178
Report Number(s):
CONF-941015-; TRN: IM9532%%305
Resource Relation:
Conference: 64. annual meeting of the Society of Exploration Geophysicists and international exposition, Los Angeles, CA (United States), 23-27 Oct 1994; Other Information: PBD: 1994; Related Information: Is Part Of SEG international exposition and sixty-fourth annual meeting -- 1994 Technical program: Expanded abstracts with authors` biographies; PB: 1736 p.
Country of Publication:
United States
Language:
English