This discussion is about knowing the Geophysical investigation for borehole drilling, geotechnical and environmental pollutants studies.

The aim for this thread is to give an insight for what Geophysical investigation is all about and to learn more from. I will need your response.

You can connect with me on 08077442292

What is Geophysical Investigation?
Geophysical investigation is using simple methods of geophysics to reveal what is in the subsurface. These methods are achieved by measuring certain physical properties and interpreting to obtain subsurface geology. This method used to locate what is in the subsurface is called Geophysical techniques.
Geophysical techniques can be used to locate buried objects, [/[b]b]chart underground utilities, [/[b]b]map faults, [b]groundwater exploration [/b]and variations in below grade conditions like depth to bedrock.  These techniques also help us understand the constructed environment, for example, we can determine the foundation characteristics of large structures such as deep foundations and dams.

Geophysical techniques/survey
The geophysical techniques are majorly divided into two; those that use natural field energy and those that make use of artificial generated energy. The natural field energy make use of the magnetic, electrical, electromagnetic and gravitational fields, while the artificially generated energy involve the generation of energy from local electrical or electromagnetic fields. It is mostly believe that natural field energy can give details of the Earth properties with very much accuracy and precision than artificial generated energy. Artificially generated energy are also capable of giving detailed information about the subsurface and clear picture of the subsurface geology.

For each of the geophysical survey methods, there is always a physical property which is peculiar to each of them. Applications of these geophysical techniques/survey is mostly determined by the physical property of the survey methods. For example, Magnetic Susceptibility is the physical property of Magnetic Method, therefore Magnetic Method is very good for locating buried Magnetite Ore bodies because the magnetic susceptibility of different ores are already known. Also, Electrical Methods are mostly used for determination of a buried water table, because saturated rock may be differentiated from dry rock by its higher electrical conductivity. Gravity method survey is sensitive to variation in rock density which is mostly used in crude oil exploration and geodesy.

Two or more Geophysical Methods can be combined together. For example, in searching for metalliferous mineral deposits, airborne Magnetic Method and Electromagnetic Method can be used for better accuracy.

Geophysical investigation acts as a primary tool in most hydrological studies in visualizing s the subsurface conditions through response if measurable physical parameters integrated with the site geological inference. Geophysical methods can help assists engineers in solving a problem through detection of different physical properties of the soil by sending physical property and receiving it again such as current, sonic waves, EM wave e.t.c.
Another method of Geophysical method is Electrical Resistivity method, this method changes the vertical and horizontal direction along the survey line is imaged. Electrical Resistivity is widely used to visualize subsurface geological structure, groundwater and lithological variation and it is suitable in detecting walls, cavities and other structures art differing depths. This method is the most method used in groundwater exploration because of its effectiveness in determining the lithology of the subsurface and showing depth.
The equipment used for electrical Resistivity is Terametter . The image of Terametter is attached below.

Ground magnetic and Gravity method are both refer to as Potential field method. Ground magnetic method is a Geophysical survey techniques that exploits the considerable difference in the magnetic properties of minerals with the ultimate objective of characterising of the Earth's subsurface. The techniques requires the acquisition of measurement of the amplitude of the magnetic field at discrete points along survey lines distributed regularly throughout the area of interest.
I will stop this lecture here if you have any questions you can reach me on 08169135992. For your borehole survey and drilling you can contact the same number too. We also do environmental studies.
Thank you.