Applications Include
Locating buried drums and othe rmetal objects
Finding abandoned well
Delineating dikes and faults
Locating utilities
Investigating landfill
Gathering of forensic evidence

This is an efficient and effective method to survey large areas for underground iron and steel objects such as tanks and barrels. Magnetic measurement of the Earth’s total magnetic field and local magnetic gradients are usually made with proton precession magnetometers at points along a line which should be oriented at a high angle to the suspected trend of structures. For local surveys, the Earth’s ambient field may be considered uniform. Local geological and cultural magnetic materials will then express their distribution by local perturbations in the Earth’s field. In general, sedimentary rocks are non – magnetic while igneous and metamorphic rocks are magnetic.

The Magnetometer -This instrument senses objects having magnetic properties. Basically, the method works on the premise that the world has a relatively static magnetic field, and cultural (and some natural) forces interrupt that field. Magnetometer surveys measure the irregularities in the magnetic field in a given area.

The Gradiometer- This instrument has two flux gate magnetic fixed sensors that are passed closely to and over the ground. When it passes over a buried iron or steel object so that the field is significantly different at the two sensors, and locally there is a high magnetic gradient, the instrument emits a high frequency sound. The frequency is a function of the gradient between the two sensors.



Magnetic Contour Maps


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