Volcanic gas near Sundhnúksgígar crater row, December 18-19th 2023
Volcanic gas near Sundhnúksgígar crater row, December 18-19th 2023
The composition of volcanic gas was measured within the first 5 hours of the eruption. The gas composition was analyzed remotely at a distance of approximately 500 meters from the fissure using open-path Fourier-transform infrared spectroscopy (OP-FTIR). These measurements are the result of collaborative efforts by scientists at the University of Iceland and the Iceland Meteorological Office.
The composition of the volcanic gas is: H2O 93-94%, CO2 4-5%, SO2 1-2%, HCl 0.09-0.13%, HF 0.07-0.09%, CO 0.07-0.09%
The composition of volcanic gas from the Sundhnúksgígar crater row is comparable to that of previous eruptions at Reykjanes in 2021-23; however, there are notable differences. The gas measured during the current eruption shows a depletion in CO2 and SO2 compared with the 2021 and 2023 eruptions and is very similar to the 2022 eruption. The the abundances of HCl, HF, and H2O remain similar (Fig. 1). This suggests that the melt erupting along the Sundhnúksgígar crater row has resided for some time, undergoing degassing within the upper part of the crust at shallow depths (<0.5 to 5 km) prior to the eruption.
Figure 1. The chemical composition of volcanic gas during the eruptions at Reykjanes in 2021-23. The gas composition emitted during the current eruption shows depletion in CO2 and SO2 that suggest degassing of the melt prior to the eruption.
