Revealing stratigraphy in ground‐penetrating radar data using domain filtering

Abstract

A common-offset ground-penetrating radar profile was collected from a mid-continent fluvial environment characterized by sand with discontinuous clay layers. Signal was separated from coherent noise by a domain filter that exploits local differences in dip between signal and noise. This filter proved effective in separating reflections from the direct air wave and from system ringing. The processed section locates the base of a Pleistocene river channel incised into bedrock and shows a change in a recent position of the river on the basis of radar character.The water table, which lies at a depth of approximately 2 m, is characterized by a continuous reflection. An earlier reflection is interpreted as a perched lens of water near the ground surface. The predominant frequency of both reflections varies greatly with position along the profile. Shallow cores taken along the profile provide evidence that grain size in the transition zone from saturated to unsaturated sediments may determine the predominant frequency of the associated radar reflection.The domain filter is also successful in separating transition zone reflections from saturated layer boundary reflections that are coincident in arrival time. It is possible, therefore, to determine both grain size in the transition zone and the dip of sediments immediately beneath it even if the reflections from the two are superimposed.

Contribution of geophysics to the study of alluvial deposits: a case study in the Val d'Avaray area of the River Loire, France

“…The data processing used were those classically employed to help elucidate vertical (stratigraphic) and horizontal (lateral continuity) profiles in sedimentary deposits. Following the work of Fisher et al (1992), Arcone (1996) and Young and Sun (1999), the frequency filters were adjusted in order to obtain maximum resolution and clarity for the various units. Since the water and clay contents change along the profile on land, there is a considerable variation in propagation velocity of the electromagnetic waves and dispersion of the spectrum (Greaves et al, 1996).…”

A practical approach to correct attenuation effects in GPR data

“…The initial distance between the antennas is 1.2 m and the step for each antenna is 0.15 m. The maximum distance between the antennas is 7.2 m. Sun, 1999). So, the contribution of the present study does not represent a new methodology procedure, but it reveals that the judicious combined use of the well known tools of time gain and spectral balancing can effectively correct the attenuation effects in GPR signals.…”

Application of deterministic deconvolution of ground-penetrating radar data in a study of carbonate strata

“…Over the last decade, ground-penetrating radar (GPR) has been widely used in environmental, engineering and groundwater investigations (e.g., Arcone et al, 1992Arcone et al, , 1998Beres and Haeni, 1991;Olhoeft et al, 1994;Powers and Olhoeft, 1996a,b;Annan, 1996;Young et al, 1997;Powers, 1997;Cardimona et al, 1998;Asprion and Aigner, 1999;Butler et al, 2000) as well as shallow sedimentary and stratigraphic studies (Arcone, 1996;Smith and Jol, 1992;Pratt and Miall, 1993;Gawthorpe et al, 1993;Beres et al, 1995;Bridge et al, 1995Bridge et al, , 1998Jol et al, 1996;Sigurdsson and Overgaard, 1996;Liner and Liner, 1997;McMechan et al, 1997McMechan et al, , 1998Martinez et al, 1998a,b;Young and Sun, 1999; 1999; Vandenberghe and van Overmeeren, 1999;Beres et al, 1999;Augustinus and Nichol, 1999;Dagallier et al, 2000;Kruse et al, 2000;Bano et al, 2000;Van Dam and Schlager, 2000).…”