Geosciences

Ground Water Prospects Mapping

Drinking Water technology mission is one of the five technology missions launched by the then Prime Minister of India (1986). Under this initiative NRSC has developed methodology and prepared Groundwater Prospects Map on 1:50,000 scale for the entire country, which is put to public usage through BUVAN BHUJAL ISRO’s Geoportal.

These maps represent groundwater yield & depth information, possible exploration zones, conservation measures, and sustainability in a holistic manner.

Ground water quality mapping is another important activity which is carried out by NRSC by organizing the seasonal quality data of geogenic contaminants, collected from wells by State Departments. The point data are interpolated in GIS environment for visualization in association with ground water prospect map, which differentiates the potable and non-potable groundwater sources.

Salt water intrusions in coastal aquifers and its impact on groundwater system is being studied based on GPR & RS techniques.

Ground water budgeting, draft estimation & modeling studies under National Aquifer Mapping & Management (NAQUIM) project has been carried out by coupling RS inputs with field-based observations.

Mineral Exploration

Earth observation data provide valuable inputs for mineral exploration. Space borne earth observation data and their derived image products provide scope for mapping the host rock and regional structures contributed in localising mineral deposit. Specialised study using hyperspectral and multispectral satellite data provide valuable information on surface distribution of alteration rocks, cap rocks associated with mineral deposit.

Ground water quality mapping is another important activity which is carried out by NRSC by organizing the seasonal quality data of geogenic contaminants, collected from wells by State Departments. The point data are interpolated in GIS environment for visualization in association with ground water prospect map, which differentiates the potable and non-potable groundwater sources.

High resolution remote sensing (HRS) data are used for mapping geological structures responsible for mineralisation. Geological themes identified using remote sensing data are integrated with ground geophysical, geochemical data to delineate prospective zone for exploration. Remote sensing studies were carried out for projects of bauxite, Chromite, diamond, Iron, Manganese, Phosphate etc. A joint study was taken with GSI for demonstrating optimum use of hyperspectral data for identifying mineralisation targets for detailed exploration. Prospectivity modelling for mineral deposit has been attempted for Bhukia and Zawar area, Rajasthan.

Geo hazard studies

The Geohazard studies are primarily focussed on landslides, earthquakes and volcanoes. High resolution satellite data are used for post disaster damage assessment and landslide inventory preparation in the case of landslide or earthquake. Major landslide events studied recently include Kerala-Karnataka-Tamil Nadu (2018), Mizoram-Tripura (2017) and Sikkim (2016). Landslide Hazard Zonation maps are made on 1:25,000 scale along major tourist and pilgrimage routes in the states of Himachal Pradesh and Uttarakhand. These maps is integrated with the rainfall forecast data to develop and issue landslide early warning through Bhuvan portal. In recent years several earthquakes struck India namely the Kashmir earthquake (2005), Sikkim earthquake (2011) and Nepal earthquake (2015). Post-disaster very high resolution (VHR) satellite data have been used to provide detailed information on damage and geological changes for a large area in a short time. In addition to these, the recent eruptions of the Barren Island volcano have also been monitored using temporal satellite data.

Geo Dynamic Studies

Monitoring crustal deformation using advanced space geodetic techniques such as the Global Positioning System (GPS) is useful for analyzing and quantifying seismic hazard in tectonically active areas. Continuously Operating Reference Stations (CORS)that use GPS are being used to measure plate movements. NRSC plans for such CORS observations along major Himalayan thrusts belts (HFT/MBT/MCT and ISSZ). For this, nine CORS have been established in Dehradun, Uttarkashi, Batwari and Roorkee(in Uttarakhand) and Manali, Chandigarh, Pinjore (Haryana), Shimla and Sundernagar in Himachal Pradesh. The preliminary displacements from each site from 2014 to 2018 have been estimated. The results of the observations are currently being analysed.

Geo Environmental Studies

Geoenvironmental studies deal with the geogenic components like rocks, relief, groundwater and geodynamic phenomena. The complex properties of these components affect the quality of environment and the landscape exploitation.

The geomorphic units along with the lithology are considered to be key element to define the environment of erosion/deposition and surface dynamics. Integration of the geomorphic sub-provinces based on the spatial extent of the quaternary deposits has helped in identification of few geo-environmental zones in parts of Bengal Delta. These zones have been characterized based on its stability, potentiality for agricultural practices, urban planning and scope of reclamation, hence providing an important input to town planners.

Mapping of Coal Fire Areas

In order to manage effectively the coal fire menace, it is essential to know the exact location and extent of the fire affected areas. Coal fire mapping carried out in the past conducting an airborne campaign in 1989 and using Landsat-5 TM data over Jharia coalfield, Jharkhand , Raniganj coalfield, West Bengal in 2001. Further coal fire of the Jharia Coalfield was mapped for 2003 and 2006, using ETM+ and ASTER data, respectively. This type of activity was further carried out in 2012 and 2017 to update the status of coal fire in the Jharia coal field. In addition to this, land subsidence detection in the Jharia coalfield was carried out using differential Interferometry. A similar study is being undertaken for Oil India Limited in Assam to detect subsidence due to hydrocarbon extraction.

Geotechnical Studies

Satellite data are useful for selection of sites for identification hydroelectric dams. High resolution IKONOS data were used for mapping on 1:5,000 scale in Middle project in Arunachal Pradesh. Detail study was carried out using IKONOS data around dam site with emphasis on shear zone identification. Structural weak zones e.g. faults and shear were also mapped which helped to identify locations of dam axis. Similar study has been carried out in Tawang Valley for dam site suitability using Cartosat-1 data. Oil pipeline alignment studies have been carried out for IOCL. Reservoir sedimentation studies are also being carried out for NHPC for Teesta stage IV dam.