Sudha Agrahari

Biography

Sudha Agrahari is an professor in the Department of Geology and Geophysics at Indian institute of Technology Kharagpur.

Research Interest

I work on the application of geoelectrical and electromagnetic methods for investigations of earth interiors. The specific problems considered are investigation of groundwater contamination, aquifer characterization, geothermal investigation and soil characterization. The integrated use of airborne and ground electromagnetic methods for geological and hydrogeological purposes is a newer approach. Particularly airborne electromagnetic methods are useful to cover large areas in short time. Therefore, I broadened my research area by using airborne and ground based electromagnetic methods jointly. By jointly inverting different kinds of geophysical measurements at a site, the ambiguity inherent in different geophysical methods can be reduced. In order to couple spatial data from frequency-domain helicopter-borne electromagnetics (HEM) with electromagnetic measurements from ground geophysics (Transient Electromagnetics (TEM) and Radiomagnetotellurics (RMT)), a common 1D joint inversion algorithm for HEM, TEM and RMT data has been developed. In order to avoid the suppression of the resolution capacities of one data type, and thus balancing the use of an inherent and ideally complementary information content, a parameter reweighting scheme is proposed, that is based on the exploration depth ranges of the specific methods. This algorithm employs the weighting on different model parameters differently. Sometimes near-surface geophysical findings show exciting features and motivate us to explore the deeper depths. Such motivations have directed me towards the exploration of the deeper subsurface using magnetotellurics (MT). Using this technique, I and my research team are collecting MT data to understand the coastal dynamics. Apart from these I am also expanding my research in the characterization of the type of contamination present beneath using Non-invasive approaches.