Magnetic and EM surveys have been used extensively to provide information on buried metallic objects and disturbed soils for characterization and remediation at hazardous waste sites. Nyquist and Blair [1991] used an ultrasonic positioning system to conduct a terrain conductivity meter (TCM) survey of Solid Waste Storage Area 4 at the Department of Energy's (DOE) Oak Ridge Reservation in Tennessee. The in-phase response was found to be superior to the quadrature response in delineating buried trench boundaries. Flynn et al. [1992] used the same equipment to survey the K1070A burial ground at the Oak Ridge Reservation. They found that the quadrature response best identified the boundaries of the burial areas. The positioning system was also used by Flynn et al. for a magnetic survey of a suspected artillery impact area at an arsenal. Doll et al. [1993] present preliminary results of an airborne magnetic and EM survey over the Waste Area Group 6 site at the Oak Ridge Reservation.
At DOE's Idaho National Engineering Laboratory (INEL) Carpenter and Deignan [1993] used a ground magnetic gradient and EM survey to map buried pits and trenches containing radioactive and mixed waste at the Subsurface Disposal Area. The trenches and pits were well resolved in both magnetic and EM data sets, indicating that all the trenches contained at least some conductive and magnetic material. In addition the in-phase EM component contained longer wavelength anomalies identified as contaminant plumes due to dumping of free solvents and acids. Hoekstra and Lahti [1994] tested magnetic, GPR, and EM methods at the Cold Test Pit at INEL. The EM methods were found to be superior to the magnetic and GPR methods at delineating the known targets in this test area.
Gilkenson et al. [1992] conducted field and
model studies to determine the characteristic responses of
magnetic total intensity, magnetic vertical gradient,
EM quadrature, and EM in-phase measurements over buried
drums. Pierce and DeReamer [1993] used a vertical
magnetic gradient survey to locate isolated buried waste drums at a 100
acre site in California. Dwyer and Johnson [1993]
located buried drums and underground tanks at an 80 acre Superfund site
in New Jersey using a vertical magnetic gradient survey.
MacLean et al. [1991] used magnetic total field,
magnetic vertical gradient, and EM methods to detect buried fuel
storage tanks at Hickman Air Force Base, Hawaii.
Foley [1994] used a towed array of magnetometers, designed for
locating unexploded ordnance, to search for buried waste containers at a
45 acre site on Kirtland Air Force Base in New Mexico. The
resulting magnetic anomalies could be presented as an image with a 10
cm resolution. The same equipment was successfully used at a Department
of Energy test range in Colorado, designed to evaluate the ability
of different geophysical techniques to locate known buried
objects [ Koppenjan and Martinez, 1994].