Ten years of satellite observations reveal highly variable sulphur dioxide emissions at Anatahan Volcano, Mariana Islands

Abstract

Satellite remote sensing enables continuous multiyear observations of volcanic activity in remote settings. Anatahan (Mariana Islands) is a remote volcano in the western North Pacific. Available ground-based measurements of sulphur dioxide (SO 2 ) gas emissions at Anatahan place it among the largest volcanic SO 2 sources worldwide. These ground-based measurements, however, are restricted to eruptive intervals. Anatahan's activity since 2003 has been dominated temporally by prolonged periods of quiescence. Using 10 years of satellite observations from OMI, AIRS, SCIAMACHY, and GOME-2, we report highly variable SO 2 emissions within and between eruptive and quiescent intervals at Anatahan. We find close correspondence between levels of activity reported at the volcano and levels of SO 2 emissions detected from space. Eruptive SO 2 emission rates have a mean value of ∼6400 t d −1 , but frequently are in excess of 20,000 t d −1 . Conversely, SO 2 emissions during quiescent intervals are below the detection limit of space-based sensors and therefore are not likely to exceed ∼300 t d −1 . We show that while Anatahan occupies a quiescent state for 85% of the past 10 years, only ∼15% of total SO 2 emissions over this interval occur during quiescence, with the remaining ∼85% released in short duration but intense syn-eruptive degassing. We propose that the integration of multiyear satellite data sets and activity histories are a powerful complement to targeted ground-based campaign measurements in better describing the long-term degassing behavior of remote volcanoes.

Aerial strategies advance volcanic gas measurements at inaccessible, strongly degassing volcanoes

“…Our measured volatile fluxes at Manam are substantially in excess of the decadal mean SO 2 emission rate (16) (1484 ± 753 [1] tons day −1 ). However, temporal variability in SO 2 emissions observed at arc volcanoes more generally (13,16,83) indicates that degassing budgets are highly dynamic and should be extrapolated with caution. The difference in satellite SO 2 mass loadings between October 2018 and May 2019 at Manam (Fig.…”

Multi-year Satellite Observations of Sulfur Dioxide Gas Emissions and Lava Extrusion at Bagana Volcano, Papua New Guinea

“…The Ozone Monitoring Instrument (OMI) is a hyperspectral UV/visible spectrometer launched in 2004 aboard the Aura satellite in NASA's A-train constellation (Levelt et al, 2006a,b). OMI observations have been widely used to study volcanic SO 2 emissions, both from discrete eruptions (Thomas et al, 2009;Carn and Prata, 2010;Lopez et al, 2013a) and over multi-year intervals on the regional and global scale (McCormick et al, 2012(McCormick et al, , 2015Carn et al, 2016Carn et al, , 2017Fioletov et al, 2016). OMI measures backscattered solar radiation from Earth's surface and atmosphere and SO 2 column concentrations have been calculated using a series of increasingly sophisticated retrieval algorithms (Krotkov et al, 2006;Yang et al, 2007Yang et al, , 2009Li et al, 2013Li et al, , 2017.…”

Satellite‐based global volcanic SO2 emissions and sulfate direct radiative forcing during 2005–2012

“…For a more detailed description of the Anatahan behavior, please refer to McCormick et al . [] in which they integrated 10 years of satellite data sets and activity histories for Anatahan. For the other persistently degassing volcanoes, the daily SO 2 amounts are less than ~ 40 kt.…”