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Quantifying the ground-penetrating radar response to ultrathin layers of nonaqueous phase liquid contaminants

Esther Babcock and John Bradford
Quantifying the ground-penetrating radar response to ultrathin layers of nonaqueous phase liquid contaminants (in Characterization and monitoring of subsurface contamination, Dimitrios Ntarlagiannis (prefacer), Rory Doherty (prefacer), Ralph Costa (prefacer), Kenneth H. Williams (prefacer), Chi Zhang (prefacer) and Pantelis Soupios (prefacer))
Interpretation (Tulsa) (November 2015) 3 (4): SAB23-SAB31


Contamination of groundwater resources is a worldwide problem that threatens human health. Characterizing the type, location, and quantity of the contamination is the first step toward successful site remediation. Ground-penetrating radar (GPR) is one geophysical tool that provides information that may be used to derive the location and quantity of nonaqueous phase liquid contaminants (NAPLs). Because of the large contrast between the dielectric permittivity of water and NAPL, GPR is sensitive to areas in which NAPL displaces pore water. We have used numerical and physical models to investigate the GPR response to ultrathin layers of dense NAPL (DNAPL) trapped at a sand/clay interface. We have defined ultrathin as one-tenth of a wavelength lambda or less at the dominant frequency of the radar signal. The numerical and physical models were in good agreement and both found an increase in reflection strength of 10% or more with partially DNAPL-saturated layer thicknesses as low as 1/50th lambda . The reflection strength generally increased with DNAPL-layer thickness reaching a 61% increase with a layer thickness of 0.17 lambda . These results were especially pertinent to field investigations because they were often limited to lower frequency radar (< 100 MHz) and NAPL accumulations may lie well below the conventional radar 1/4 lambda radar resolution limit.

ISSN: 2324-8858
EISSN: 2324-8866
Serial Title: Interpretation (Tulsa)
Serial Volume: 3
Serial Issue: 4
Title: Quantifying the ground-penetrating radar response to ultrathin layers of nonaqueous phase liquid contaminants
Title: Characterization and monitoring of subsurface contamination
Author(s): Babcock, EstherBradford, John
Author(s): Ntarlagiannis, Dimitriosprefacer
Author(s): Doherty, Roryprefacer
Author(s): Costa, Ralphprefacer
Author(s): Williams, Kenneth H.prefacer
Author(s): Zhang, Chiprefacer
Author(s): Soupios, Pantelisprefacer
Affiliation: GeoTek Alaska, Anchorage, AK, United States
Affiliation: Rutgers University-Newark, Department of Earth and Environmental Sciences, Newark, NJ, United States
Pages: SAB23-SAB31
Published: 201511
Text Language: English
Publisher: Society of Exploration Geophysicists, Tulsa, OK, United States
References: 30
Accession Number: 2016-007519
Categories: Environmental geologyApplied geophysics
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. 4 tables
Secondary Affiliation: Queens University-Belfast, GBR, United KingdomWeston Solutions, USA, United StatesLawrence Berkeley National Laboratory, USA, United StatesKansas University, USA, United StatesTechnological Educational Institute of Crete, GRC, GreeceBoise State University, USA, United States
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute. Reference includes data from GeoScienceWorld, Alexandria, VA, United States
Update Code: 201604
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