Question

Which geophysical method is most suitable for locating groundwater aquifers?

• A. Magnetic method
• B. Gravity method
• C. Electrical resistivity method
• D. Seismic refraction method

Hint:

{Low resistivity = Presence of water}. Electrical resistivity surveys are the most commonly used method in groundwater exploration.

Answer 1

The Correct Option is C

Step 1: Understanding groundwater detection.
Groundwater occurs in subsurface porous and permeable formations. These formations generally contain water that significantly affects the electrical properties of the subsurface materials.
Step 2: Principle of electrical resistivity method.
The electrical resistivity method works on the principle that water-saturated rocks have lower electrical resistivity compared to dry or compact rocks. By measuring variations in resistivity, groundwater-bearing zones can be identified.
Step 3: Evaluating other methods.
(A) Magnetic method: Mainly used for detecting magnetic minerals, not groundwater.
(B) Gravity method: Useful for large-scale density variations, not ideal for shallow aquifers.
(D) Seismic refraction method: Used for subsurface layering and bedrock depth, but less effective for direct groundwater detection.
Step 4: Conclusion.
Since groundwater significantly reduces electrical resistivity, the electrical resistivity method is the most suitable technique for locating groundwater aquifers. Hence, option (C) is correct.