The Indian Network for Detecting Radon Anomaly signal for Seismic Application.

The Indian Network for Detecting Radon Anomaly Signal for Seismic Application (INDRA-SA) has been established to investigate ground radon exhalation as a potential earthquake precursor in the Indian subcontinent. As part of this initiative, up to 100 BhaROSA (Bhabha Radon Observatory for Seismic Application) systems have been deployed near active fault lines across the Indian Tectonic Plate. Each self-sustaining, solar-powered BhaROSA unit is equipped with a radon accumulator, a continuous radon monitor, environmental shielding, battery backup, and secure data transmission via 3G/4G GPRS on a Virtual Private Network. Site selection focused on regions with significant seismicity, particularly the Himalayan fault system and faults in the Eastern and Western Ghats. Data from each station is transmitted every 15 min to a central server, which also integrates earthquake event data from national and international agencies. At the central station, post-processing filters out meteorological noise (e.g., diurnal cycles, rainfall, low pressure) to isolate potential precursory radon anomalies. Analysis of data from notable earthquakes in the study region revealed persistent radon anomalies occurring days to months before major events. Rare radon signals preceding rare seismic events in low-activity zones further support a strong correlation. The INDRA network provides valuable insights into the spatial and temporal responses of radon signal prior and post seismic events to enhance our understanding of the complex processes involved in earthquake nucleation along fault lines. This initiative is a significant step towards advancing earthquake predictability- a longstanding and unresolved challenge for humanity.