Journal de géologie et géophysique
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Spatial Confirmation of Major Lineament and Groundwater Exploration using Ground Magnetic Method near Mecheri Village, Salem District of Tamil Nadu, India

Muthamilselvan A*, Srimadhi K, Nandhini R, Pavithra P, Balamurugan T and Vasuki V

Geophysical methods are widely used in various applications, especially to know about the subsurface features of the Earth. In the present study, the ground magnetic method has been done to map the NE-SW trending major fault traversing Mecheri block, Salem district for the spatial correlation study and also to locate possible groundwater potential zones with in the study area. The instrument used is Proton Precession Magnetometer-600 which produces a weak magnetic field that is picked up by an inductor, amplified electronically, and fed to a digital frequency counter whose output is typically scaled and displayed directly as field strength. The survey is done across the major fault marked by the GSI geologist with 100 m spacing in profile direction and 30 m sample spacing along the profile and for each profile line, 14 to 15 samples have been collected along with coordinates, time and magnetic value with all the necessary precautions. Then the data is processed and diurnal corrections were made for the interpretation using geophysical software. After the necessary corrections, profiles, contours and maps were generated for quantitative and qualitative analysis which includes magnetic contour map, total magnetic intensity, reduction to pole, analytical signal, upward and downward continuation, horizontal and vertical derivative, and radially average power spectrum. Based on the visual interpretation and interpreter’s knowledge, it was identified that the major NE-SW trending magnetic break is present at the southeastern corner of the map which is spatially correlated with the major fault marked by the GSI geologist. Apart from that there are two magnetic highs were notice in the southwestern part of the map which is mainly due to presence of isolated granite and syenite bodies. A small another magnetic break in the E-W direction has also been noticed. Intersection point of the NE-SW and NW-SE fault zones are favorable zone for groundwater potential zone. Other than this, the magnetic anomaly depth has been inferred from the radially average spectrum method shows the anomaly at 11 m, 21 m and 51 m depth.