INVESTIGATION OF AN AIRBORN RESISTIVITY SURVEY CONDUCTED AT VERY LOW FREQUENCY

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. /Author/

• Corporate Authors:

  U.S. Army Cold Regions Research and Engineering Laboratory

  72 Lyme Road
  Hanover, NH  United States  03755-1290
• Authors:
  • Arcone, S A
• Publication Date: 1977-8

Media Info

• Features: Appendices; Figures; References; Tables;
• Pagination: 57 p.

Subject/Index Terms

• TRT Terms: Aerial surveying; Amplitude (Physics); Antennas; Bedrock; Electrical resistivity; Frequency (Electromagnetism); Geology; Igneous rocks; Resistivity method; Topography
• Old TRIS Terms: Aerial surveys; Resistivity
• Subject Areas: Geotechnology; Highways;

Filing Info

• Accession Number: 00167835
• Record Type: Publication
• Report/Paper Numbers: CRREL Report 77-20
• Files: TRIS
• Created Date: Mar 7 1978 12:00AM