Groundwater depletion in Delhi–NCR has traditionally been attributed to rapid urbanisation, population growth, and excessive abstraction; however, emerging evidence suggests that neotectonic processes may also play an important role. The present study reports findings from a hydro-seismic investigation conducted in the Aravalli foothill region of Faridabad using continuous observations from 17 Digital Water Level Recorders (DWLRs) installed in piezometers at depths ranging from 45 to 75 m. On 13 May 2024, the study area experienced a shallow local earthquake of magnitude 2.3 at an approximate depth of 5 km. Groundwater-level fluctuations were temporally associated with this seismic event, with an abrupt fall of 0.15–4.07 m recorded in four wells. The magnitude of response was greater in the deeper aquifer system (~ 60–66 m) and more modest in the shallower aquifer zone (~ 42–55 m). The absence of response in several wells, together with simultaneous instrument failure in some locations, further highlights the marked heterogeneity of the aquifer system. The hydrogeological significance of these observations is strengthened by the broader regional context, including the sudden desiccation of Badkhal Lake in 2006 and the persistence of perennial spring discharge in the upstream reaches, both of which are suggestive of neotectonic control over catchment–aquifer dynamics. Collectively, these findings provide fresh evidence that even low-magnitude minor seismic activity can influence groundwater behaviour of the tectonically sensitive region like Delhi–NCR. The study, therefore, underscores the importance of incorporating hydrogeological susceptibility indicators into seismic hazard assessment frameworks. Furthermore, the integration of high-frequency telemetric monitoring with post-seismic groundwater-quality surveillance may substantially improve groundwater assessment and management in structurally complex and rapidly urbanising terrains.
Mukherjee et al. (Mon,) studied this question.