Abstract
Awu is one of the remote and little known active volcanoes of Indonesia.
It is the northernmost active volcano of Sangihe arc with 18 eruptions
in less than 4 centuries, causing a cumulative death toll of 11048. Two
of these eruptions were classified as VEI 4. Since 2004, a lava dome
occupies the center of Awu crater, channeling the fumarolic gas output
along the crater wall. A combined DOAS and MultiGAS measurements
highlight a relatively small SO degassing (13 t/d) into the atmosphere.
In contrast the measurements spotlight an elevated and non-negligible CO
emission into the atmosphere of 2600 t/d, representing 1% of the global
CO emission budget from volcanoes. The cause for this high CO degassing
may reside in the peculiar geodynamic context of the region, where the
slowing down of arc-to-arc collision has enhanced heating of the slab,
leading to greater production of fluid rich in carbon.