Accession Number : ADD010809

Title :   Method for Rapidly Detecting Subterranean Tunnels by Detecting a Non-Null Value of a Resultant Horizontal Magnetic Field Component.

Descriptive Note : Patent,

Corporate Author : DEPARTMENT OF THE NAVY WASHINGTON DC

Personal Author(s) : Hansen,P M ; Hoffman,J G ; Seeley,E W ; Andrew,W A

Report Date : 12 Jul 1983

Pagination or Media Count : 6

Abstract : This invention provides for the detection and location of subterranean tunnels, voids and other anomalies. Two magnetic fields are established by passing current in two parallel wires laid out horizontally on the earth's surface in the general area in which an anomaly is known or suspected to be. Magnetic field null measurements are made along a center line between the parallel wires. The presence of a tunnel warps or distorts the magnetic fields and causes the signal level to increase when the measurement is made over the tunnel or void beneath. (Author)

Descriptors :   *Patents, *Magnetic anomaly detection, *Tunnels, *Underground structures, Methodology, Magnetic fields, Magnetic anomalies, Voids

Subject Categories : Civil Engineering
      Magnetic & Electric Fld Detection & Detectors

Distribution Statement : APPROVED FOR PUBLIC RELEASE