The little known Awu volcano is among the highest CO2 degassing source on earth

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.