Modest volcanic SO₂ emissions from the Indonesian archipelago

Area of Science:

• Geochemistry
• Volcanology
• Environmental Science

Background:

• Indonesia has the most active volcanoes globally, with some known for significant historical eruptions.
• Previous research lacked sufficient data on sulfur dioxide (SO2) emissions from Indonesian volcanoes.
• The potential for substantial global volcanic SO2 contributions from Indonesia was hypothesized but unevaluated.

Purpose of the Study:

• To quantify current SO2 emissions from Indonesian volcanoes.
• To investigate the geodynamic, petrologic, and magmatic factors influencing sulfur transfer to the atmosphere.
• To reconcile the paradox of Indonesia's volcanic activity and its SO2 emission levels.

Main Methods:

• Conducted new gas measurements at Indonesian volcanoes.
• Calculated combined SO2 output from continuous emissions.
• Estimated SO2 yield from explosive eruptions.
• Compared Indonesian emission data with global volcanic SO2 fluxes.
• Analyzed magmatic and hydrothermal processes influencing sulfur degassing.

Main Results:

• The total SO2 inventory for Indonesian volcanoes is estimated at 1.27–1.69 Tg/yr.
• This total SO2 output is comparatively modest, with some individual volcanoes like Etna exhibiting higher sustained fluxes.
• Sulfur-rich eruptions are linked to the long-term accumulation of volatiles in magma reservoirs.

Conclusions:

• Despite hosting numerous active volcanoes, Indonesia's overall SO2 emissions are not a dominant factor in global volcanic sulfur output.
• The study highlights the importance of understanding magmatic and hydrothermal systems in controlling volcanic gas release.
• Long-term volatile accumulation in magma reservoirs is a key factor in sulfur-rich explosive eruptions.