CSIR-NGRI

Research Roundup

Groundwater depletion in North West India and its response on crustal deformation.

Rajewar SK, Asoka A, Krishnan KCS, Puviarasan N, Purohit R, Bhu H, Gahalaut, VK.

NEAR SURFACE GEOPHYSICS

Measurements from the Gravity Recovery and Climate Experiment (GRACE) mission of time variable gravity fields have significantly improved the ability to monitor regional mass changes associated with terrestrial water storage, ice, oceans, drought conditions, and groundwater depletion. Continuous Global Positioning System (GPS) observations across the region reveal crustal deformation signals associated with groundwater mass loss. A strong correlation is observed among regional rainfall patterns, GRACE-derived mass variations, GPS-measured crustal deformation, and groundwater level changes from wells. The seismic activity in and around the Delhi region is primarily governed by the tectonic framework of the Delhi-Aravalli fold belt paleo-structure, our findings suggest that groundwater depletion may also influence earthquake occurrence. The observed uplift indicates fault unclamping resulting from mass loss, potentially promoting fault instability and increasing the likelihood of seismic events.

Fig: Secular rate of Gravity Recovery and Climate Experiment (GRACE)-derived equivalent water height (EWH) for a period of (2002-2023) in (mm/year) as the background image with corresponding contours of EWH. Yellow-filled circles are the earthquakes during 1960-2022. The inset map shows the EWH on the Indian subcontinent with a rectangle marking the North West (NW) India region.