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|Title:||Investigation of an airborne resistivity survey conducted at very low frequency|
Arcone, Steven A.
|Publisher:||Cold Regions Research and Engineering Laboratory (U.S.)|
Engineer Research and Development Center (U.S.)
|Series/Report no.:||CRREL report ; 77-20.|
Abstract: An airborne survey of earth electrical resistivity, computed from the complex tilt of the electric field vector of a VLF (17.8 kHz) radio surface wave, has been studied. The survey was conducted at a 150-m mean flight altitude. The bedrock of the survey area was slate containing an igneous stock. Topography was found to distort the resistivity contours through its effect upon the vertical component of the electric field. At 300-m flight altitude most resistivity information was retained due to the deterioration of topographic influence. The phase of the tilt, which cannot be distinguished from the amplitude by an airborne antenna system, was determined from a ground survey of the surface impedance and was found to be an important influence on the airborne detection of high resistivity areas. The entire 150-m survey was reevaluated with topographic effects removed. The resolution of the igneous geology improved and several of these improvements were verified by the ground measurements.
|Rights:||Approved for public release; distribution is unlimited.|
|Appears in Collections:||CRREL Report|
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|CR-77-20.pdf||10.39 MB||Adobe PDF|