Abstract/Summary

Bagana is a young (300-400 years) polygenetic andesitic volcano situated on Bougainville Island, Papua New Guinea, that lends itself to satellite remote sensing due to its largely inaccessible location. Bagana is unusual in the amount of SO2 it outputs, and its high rate of lava extrusion. Previous work noted with lava mass fluxes from Interferometric Synthetic Aperture Radar (InSAR) data that there is cyclicity of a few months over a 14 month period, and others examined trends in the SO2 degassing against thermal data, suggesting there were two eruption behaviours demonstrated. 1,2 Using a unique combination of data sources, this study has found evidence of cyclicity in SO2, thermal infra-red and InSAR data, where the significant cycles identified are at 16 days (SO2) and 133 days (thermal). Additionally, this study showed there are three observed eruption styles at Bagana. There is evidence to indicate that SO2 peaks are related to elevated thermal signals on a 4-5 month cycle. These peaks coincide with lava flows imaged by Sentinel-2 that provide some verification for the conclusions drawn. This may provide insight as to Bagana’s cycles compared with other volcanoes in similar arc settings, with the most comparable processes seen at Soufrière Hills Volcano, with its 8-14 day cycle in SO2, and Popocatépetl with its 1.7-7 month dome-building cycle.