Volatile characteristics and fluxes of He-CO2 systematics in the southeastern Tibetan Plateau: Constraints on regional seismic activities

•The volatiles of the hot springs come mainly from the crust, with only a small amount from the mantle.•The tectonic stress field at the converging plate boundary limits the crustal helium flux.•Carbon sequestration of calcite precipitates slows down carbon flux in the collision zone.•Crust within the convergent boundary has the potential to produce a significant proportion of volatiles.•Coupled overpressure and stress fields in the rigid crust may lead to high seismic risk in this area.