Methodologies

Magnetics (land and marine): Magnetometers are designed to measure variations in the magnetic field of the Earth. These are usually caused by the presence of magnetically susceptible material of natural or human origin. In certain instances, magnetic data can be interpreted quantitatively, and transformed into constrained geologic models. More typically, however, magnetic data are interpreted qualitatively, and simply used to verify the presence or absence of magnetically susceptible materials.

Modified from “Introduction to Geotechnical Geophysics – N. Anderson and N. Croxton, Circular – Number E-C130, October 2008”.

Marine magnetics involves the towing of a magnetometer from a vessel. The magnetometer is towed as close as possible to the seabed to maximise the depth of penetration of the investigation.

Land magnetics can be carried out by walking pre-determined lines with a magnetometer or mounted on a non-ferrous cart and towed by a vehicle.

Contoured plot of Marine magnetics data. Investigation was carried out to locate buried pipelines.