Delineation of voided and hydrocarbon contaminated regions with REDEM and STI
- Brown & Caldwell, Turramurra (Australia)
Undetected voids and cavernous regions at shallow depth are a significant geotechnical and environmental hazard if they are filled or act as conduits for pollutants, particularly for LNAPL and DNAPL contaminants. Such features are often difficult to locate with drilling and conventional geophysical methods including resistivity, electromagnetics, microgravity, seismic and ground penetrating radar when they occur in industrial or urban areas where electrical and vibrational interference can combine with subsurface complexity due to human action to severely degrade geophysical data quality. A new geophysical method called Radiowave Diffraction Electromagnetics (RDEM) has proved successful for rapid screening of difficult sites and for the delineation of buried sinkholes, cavities and hydrocarbon plumes. RDEM operates with a null coupled coil configuration at about 1.6 MHZ and is relatively insensitive to electrical interference and surrounding metal objects. It responds to subsurface variations in both conductivity and dielectric constant. Voided and contaminated regions can be more fully detailed when RDEM is combined with Seismic Tomographic Imaging (STI) from follow-up boreholes. Case studies from sites in Australia and South East Asia demonstrate the application of RDEM and STI and the value in combining both methods.
- OSTI ID:
- 526129
- Report Number(s):
- CONF-970344-; TRN: 97:003014-0027
- Resource Relation:
- Conference: SAGEEP `97: 10. annual symposium on the application of geophysics to environmental and engineering problems, Reno, NV (United States), 23-26 Mar 1997; Other Information: PBD: 1997; Related Information: Is Part Of Proceedings of the symposium on the application of geophysics to engineering and environmental problems. SAGEEP `97: Volume I and II; Bell, R.S. [comp.]; PB: 1096 p.
- Country of Publication:
- United States
- Language:
- English
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