Importance of Geophysical Surveys — Methods and Uses

Geophysical survey has different applications in different disciplines like archaeology, mineral prospecting, Geology and so on. However, its main purpose remains the same. It is the process of collecting systematic information and geophysical data for spatial studies.

In the context of archaeological studies, it involves using different techniques like the ‘ground based physical sensing’ which is used for archaeological mapping and imaging. Likewise, in the context of mineral prospecting, a geophysical survey is done to measure the level of deposits and evaluate their grade and tonnage.

However, there are few methods used commonly to conduct geophysical surveys in different disciplines.

Electromagnetic Methods:This method uses the principle of induction to check the electrical conductivity of the subsurface. It is deployed to get rid of electrical coupling problems and get data acquisition rapidly without making ground contact. As the EM tools provide data easily and quickly, they are used to identify irregularities for greater detailing.

Ground Penetrating Radar Methods:Ground Penetrating Radar (GPR) is used for finding the exact location of objects and stratigraphic imaging through the cross-sectional dimensions of a shallow subsurface. The best part is, unlike conventional metal detectors, GPR’s can locate both metal and non-metal objects.
It provides data in detail and the results are displayed on a computer screen attached to it. It provides fast and efficient interpretation at the site. If required, further interpretation of data can be done later in the office as there will be detailed recordings readily available.

Magnetic Methods:This is a very powerful method used to survey large areas and detect big iron and steel objects such as tanks and barrels. Magnetic surveys are used to locate buried drums and tanks, find abandoned wells, mapping geological structures, inspect landfills and collect forensic evidence.

Seismic Methods:Seismic methods provide complete details about subsurface layering and the geomechanical properties of the rocks using seismic waves. In general, this technique is used to determine rock quality, site geology and stratigraphy.

Gravitational Methods:This is used to check the variations in the acceleration due to gravity on earth. The state-of-the-art meters are so powerful that they can sense the differences in one-billion units. This is done to detect fault problems, intrusive delineations, ground water inventories and basin studies.

These are the popular methods used to get different sets of information for different purposes. Geophysical surveys are usually conducted by various public and private sector companies to detect various anomalies and prevent potential disasters.