Variable SO2 emission rates for Anatahan volcano, the Commonwealth of the Northern Mariana Islands: Implications for deriving arc‐wide volatile fluxes from erupting volcanoes

Abstract

We report new spectroscopic‐derived SO2 emission rates for Anatahan volcano, Mariana Islands. Measurements of SO2 fluxes reveal large fluctuations over the 2003–2005 period ‐ from 78 kg s−1 which occurred on the same day as resurgent volcanic activity (March, 2005) to 50 kg s−1 and 25 kg s−1 made days/weeks after the start of eruptive sequences in 2003 and 2004 respectively. Even the lowest values make Anatahan a major global source of SO2 over the past decade. These SO2 emission rates are used to estimate the CO2 flux from the arc as a whole (=3.6 − 40 × 107 mol km−1 yr−1). Such values are significantly higher than estimates derived using other approaches: they are also high compared to other convergent margins (e.g., Central America) where the input flux of CO2 is substantially greater. Our results caution against including volatile fluxes from actively‐degassing volcanoes to produce volatile outputs considered representative of entire arc fronts.