First estimate of volcanic SO2 budget for Vanuatu island arc

We provide the first volcanic SO2 emission budget at the arc scale for the Vanuatu
archipelago, based on repeated DOAS measurements in 2004–2009 and space-borne OMI
survey in 2004–2011. This reveals the arc to emit around 3 Tg year− 1 of SO2 into the
atmosphere on average, without considering sporadic eruptions or/and extreme passive
degassing events. Such a budget represents about one-fifth of currently estimated global
volcanic SO2 output and, therefore, highlights that the Vanuatu archipelago will have to be
taken into account in updating global volcanic inventories in future.
 

ur results confirm the prodigious degassing of Ambrym volcano, with an average SO2
output of 5 Gg day− 1, representing nearly two-thirds of the Vanuatu SO2 budget. This places
Ambrym in the top rank of persistent volcanic volatile sources worldwide, alongside Mount
Etna in Sicily. Ambae volcano also emerges as a prominent SO2 source, with an output of ~ 2
Gg day− 1 representing 28% at least of the arc budget. Further work will be needed to
elucidate whether such elevated degassing at Ambrym and Ambae results from the inflow of
S-rich Indian-type mantle beneath the central segment of Vanuatu arc or/and high magma
production rates facilitated by the complex local tectonic structure.