GPR for earth and environmental applications: Case studies from India

Abstract

Ground Penetrating Radar (GPR) is widely applied for rapid and precise mapping of the near surface structures. We performed GPR survey using Terra Sirch-3000 single channel control GPR meter with 2D data collection for civil engineering, environmental, archeological, geological features, aquifer contamination and seawater intrusion studies in Indian context. The 200 MHz and 400 MHz frequency antennae with adjusted dielectric constant, scans per unit, range, transmit rate, gain points, and filters were used for attaining the targets depth up to 3–8 m. The collection of GPR data was on Geologic Scan, Utility Scan, Structure Scan, and Terra SIRch modes with resolution of 16 bits, and was processed in RADAN (version 5.0) using various options to get clear anomaly of the targets. Based on the targets, the scanned images were verified with excavations, electrical resistivity tomography, and soil and water chemistry which were complementing with the GPR anomalies. Results demonstrated in this article are, 1) identification of caving in trenchless MS pipe of 1700 mm diameter with feasibility for trenchless technology, 2) discovery of ancient temple, 3) deciphering a subsurface intrusive body (i.e. dolerite dyke), 4), detection of clandestine pipes, 5) demarcating fresh groundwater zones within industrial clusters, and 6) identification of seawater intrusion in coastal area. The study establishes that the GPR works as rapid tool in unraveling shallow subsurface complexities with high-resolution images and offers a geophysical tool for wide range of earth and environmental management.