The effect of a dipping layer on the first-arrival traveltime from zero-offset and fixed-offset borehole radar

Dale Rucker, Paul A Ferre

Research output: Contribution to journalArticle

4 Citations (Scopus)

Abstract

The effect of a dipping layer on the first-arrival traveltime from single-offset profiling with borehole radar is investigated, including both zero-offset and fixed-offset profiling. In our study, offset refers to the vertical distance between bistatic radar antennae. Using forward modelling of electromagnetic wave travel, the traveltime of zero-offset and fixed-offset profiles through a dipping layer is compared to those of flat-lying layers. The model considers three distinct raypaths: direct, critically refracted and cross-dip refracted. Whereas critical refraction only occurs in a layer of low propagation velocity relative to an adjacent high-velocity layer, cross-dip refraction can occur in any velocity structure. The forward model demonstrated that the slope of the traveltime through the cross-dip portion of the profile is approximately half of that in the critically refracted portion. To obtain the electromagnetic wave propagation velocities above and below the dip, only one profile is necessary. However, to invert for the dip angle and position, two profiles with different offsets must be considered together.

Original languageEnglish (US)
Pages (from-to)151-159
Number of pages9
JournalNear Surface Geophysics
Volume5
Issue number3
StatePublished - Jun 2007

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boreholes
dipping
arrivals
radar
dip
borehole
propagation velocity
profiles
electromagnetic wave
refraction
electromagnetic radiation
radar antennas
multistatic radar
flat layers
travel
low speed
forward modeling
wave propagation
velocity structure
antenna

ASJC Scopus subject areas

  • Geophysics

Cite this

The effect of a dipping layer on the first-arrival traveltime from zero-offset and fixed-offset borehole radar. / Rucker, Dale; Ferre, Paul A.

In: Near Surface Geophysics, Vol. 5, No. 3, 06.2007, p. 151-159.

Research output: Contribution to journalArticle

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