Shallow Geophysical Survey
Is a method of non-invasive investigation of the near-surface geology and subsurface features. It involves the use of various geophysical techniques to collect data about the physical properties of the earth materials in the uppermost layers of the ground, typically down to a depth of a few tens of meters.
The survey typically involves the deployment of instruments such as ground-penetrating radar, electrical resistivity meters, magnetic sensors, and seismic instruments to measure various parameters such as the electrical conductivity, magnetic susceptibility, and density of the subsurface materials.
The data collected from these instruments can be used to create images or maps of the subsurface features, which can provide information on the geological structures, buried artifacts, and potential hazards such as sinkholes, voids, or buried waste.
Shallow geophysical surveys are commonly used in a variety of fields, including environmental assessment, engineering geology, archaeology, and geohazard assessment.
Resistivity
Resistivity and Induced Polarization are two common geophysical techniques used in shallow subsurface investigations.
Resistivity refers to the ability of a material to resist the flow of an electric current. In geophysics, electrical resistivity measurements are used to infer subsurface properties by measuring the electrical resistance of the ground to a small electrical current that is injected into the subsurface.
The resistivity of the subsurface is affected by the composition, structure, and fluid content of the materials, and can provide information on the presence and extent of geological features such as bedrock, sediment layers, or water-bearing zones.
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Induced Polarization (IP)
is a geophysical technique that measures the time-dependent voltage response of subsurface materials to an electrical current. It is particularly useful for detecting the presence of metallic minerals or clay-rich materials, which can exhibit a time-varying electrical charge buildup in response to an electrical current.
By measuring the electrical polarization of the subsurface, IP surveys can help identify the presence of ore bodies, mineral deposits, or other subsurface features with high metallic content. Both resistivity and induced polarization surveys can be conducted using specialized instruments such as resistivity meters or IP systems, and the resulting data can be analyzed and visualized using various software tools to create maps or cross-sections of the subsurface.
These techniques are widely used in a variety of fields, including mineral exploration, groundwater investigation, and environmental site assessment.
