Combined impact of climate and seismic activity on groundwater hydrogeochemistry in the Eastern Southern Alps, Italy

characterized by elevated Na, Cl, and temperatures, suggesting contributions from deeper sources. Stable isotopes of water and dissolved gases confirm meteoric origin for all springs, while 87 Sr/ 86 Sr, trace elements, and geothermometers further support deep inputs at Canal and Colesei. Statistical analyses (Principal Component Analysis and Change Point Detection) identified geochemical anomalies possibly linked to (i) prolonged drought, which reduced aquifer recharge and enhanced ion concentrations, and (ii) seismicity, notably a M w 5.8 earthquake ~245 km away, potentially varying mixing between shallow and deep systems. These results highlight the outstanding need for integrated monitoring to understand and manage groundwater resources, particularly in tectonically active and densely populated areas facing climate change and extreme events.