A magnetometer is a device that monitors the intensity of the Earth’s magnetic field across a specific distance when measured along consecutive flight lines. An airplane or helicopter equipped with a magnetometer can conduct geological mapping over broad areas. A magnetic survey through the above method is speedy and effective in mapping since the speeds and areas covered by both vehicles are high.
Detecting Minerals Within the Earth
Each type of mineral has its magnetic susceptibility, which means that different geological units beneath the ground can produce local magnetic field disturbances that can be detected by the magnetometer. Therefore, companies excavating minerals will require such magnetometer geology services.
Expect a magnetic survey by a magnetometer to map changes in mineral deposits and identify rock types and their geological features.
Using One or Two Sensors
Magnetometers use either a single sensor or two sensors to measure the gradient of the magnetic field or the difference between sensors used in a geophysical survey. However, if the distance between the sensor and the source is high, the magnetic field’s resolution drops, making ground-based systems more beneficial.
Direct Detection Through Magnetic Surveys
Direct detection is a process to determine the magnetic signature of mineral crystals or iron ores and is the most prevalent kind of detection in current use. This could lead to exact rock formation maps, enabling geologists to establish the “story” of every rock formation. The story can be linked to the potential of containing unusual ores.
Archaeology is all about locating treasures hidden beneath the Earth’s surface, and the magnetometer helps locate lost artifacts. Magnetometers are also helpful for archaeologists to find remains under the surface. Observing the effects of buried objects on the geomagnetic field, it becomes possible to detect what is underneath without digging it up.
Several Uses of Magnetometers
Detecting minerals and helping archeologists aren’t the only uses of a magnetometer. Here’s a look at the other benefits:
- Miniature magnetometers can be found in smartphones these days to function like compasses.
- Magnetometers are used to locate geological features which prevent companies from drilling.
- Shipwrecks and submerged archaeological sites can be located using these gadgets.
- Magnetometers are capable of monitoring heartbeats.
- These devices can be lowered into boreholes, towed behind quad bikes, or put into aircraft or spacecraft as per the application.
- Submarine activities are monitored using arrays of magnetometers laid on sea floors.
- Fluxgate magnetometers measure the direction and magnitude of the suns or moon’s magnetic field.
Technical Specifications of a Magnetometer
Technical specifications help determine the capability and performance of a magnetometer. The different parameters that are used are:
- Thermal Stability- The temperature is an important factor on which the instrument’s measurement depends
- Heading Error- If the instrument’s orientation changes in a constant magnetic field, it leads to a change in the reading. The change is known as a heading error.
- Noise- Random fluctuations may occur due to the magnetometer’s electronics or sensors.
- Gradient Tolerance-A magnetometer’s capability to produce an accurate measurement despite a magnetic field gradient
- Sample Rate- This is the term for the number of readings given by the magnetometer every second. The sample rate is critically important for a mobile magnetometer. The vehicle speed and sample rate together can determine the distance between measurements.
- Bandwidth or Bandpass- The rate at which a magnetometer monitors changes in the magnetic field
- Resolution- The smallest change in the magnetic field that the magnetometer can rectify
