Importance of a Magnetometer for Geophysical Surveys

One of the most important areas of geophysical surveys is the base station. These are usually located near the studied area but far from any known magnetic sources. The magnetometer at the base station records magnetic data continuously throughout the survey, and these records serve as a reference point for processing the data later.

The magnetic data are then processed to remove the variations in inducing fields due to external sources. A magnetometer used in Geology will supply a data table to help you select the right one for your needs. Get a magnetometer for a geophysical survey and see the difference!

Fluxgate magnetometers

A fluxgate magnetometer used in Geology is a type of magnetic sensor. It uses two cores, one magnetized and one unsaturated, wrapped in wires. The core alternates between being magnetized and unmagnetized, and its electronic response is measured by a detector. The stronger the magnetic field is near the core, the more easily the core becomes saturated. This produces a signal whose strength varies with the intensity of the external field.

High-field fluxgate magnetometers are used on space missions and are a vital part of the Pioneer 11 mission. These magnetometers extend the range of magnetic measurements at a minimum volume and power. They are useful for exploring the magnetospheres and interplanetary medium and are highly stable. Fluxgate sensors are used for geophysical surveys in various conditions, including planetary atmospheres, ice sheets, and ice caps.

Bell-Bloom magnetometers

A Bell-Bloom magnetometer is a magnetic field sensor that uses modulated light to change its signal. The device’s name derives from two scientists who first studied this effect. It uses light to create a signal of a particular frequency, which changes depending on the direction of the external magnetic field. Geophysical surveys, especially those involving unexploded ordnance detection, require high-performance magnetometers.

Surface-towed magnetometers

Magnetic data can help determine the location of buried wrecks, which can be difficult to locate with conventional seismic techniques. The magnetometer can be used with a side scan sonar, which creates a map by bouncing sound waves off features on the seafloor. While this method is not ideal because it cannot pick up artifacts buried deep underground, it is useful for locating artifacts on the seafloor. The combination of the two can produce maps of the location and relationship of different wreck fragments. This data can help fill in any gaps in existing knowledge. A Surface-towed magnetometer for a geophysical survey is vital.

Final Take

Magnetic surveys require accurate data. Magnetic instruments can provide detailed information about the depth, shape, and size of objects in a region. These instruments are towed in special housings and can be towed behind a research vessel. These magnetometers can also be mounted on an aerial drone. These sensors sample background magnetism at a rate of one hertz per second. The readings from a magnetometer are generally consistent unless the device detects a ferrous object, such as a ship hull fragment, anchor, or geological formations made of basalt. In these cases, the instrument detects anomalies, such as artifacts, shipwrecks, or other materials, such as icebergs or sand.

Comments are closed