CO2 emissions during the 2023 eruption in Reykjanes, Iceland: δ13C tracks magma degassing

Abstract We report CO2 emission rates and plume δ13C during the July 2023 eruption at Litli Hrútur in the Fagradalsfjall region of the Reykjanes Peninsula. The CO2 emission rates were measured by UAV utilizing a new method of data extrapolation that enables obtaining rapid flux results of dynamic eruption plumes. The δ13C values are consistent with extensive magma degassing fractionation during and after the eruption. Our results show that rapid, real-time CO2 flux measurements coupled with isotopic values of samples collected at the same time provide key insights into the dynamics of volcanic eruptions and have the potential of forecasting the onset and termination of activity.