On 14 August the Vanuatu Geohazards Observatory reported that [volcanic tremor] at Gaua had increased [slightly] since June.... The Alert Level remained at 1 (on a scale of 0-4) [and ash plumes remained likely]. [The last clear report of ash emission was in October 2011. Steam plumes were observed from aircraft on 29 April and from the International Space Station on 31 May 2013.]

Geological Summary. The roughly 20-km-diameter Gaua Island, also known as Santa Maria, consists of a basaltic-to-andesitic stratovolcano with an 6 x 9 km summit caldera. Small vents near the caldera rim fed Pleistocene lava flows that reached the coast on several sides of the island; littoral cones were formed where these lava flows reached the ocean. Quiet collapse that formed the roughly 700-m-deep caldera was followed by extensive ash eruptions. The active Mount Garet (or Garat) cone in the SW part of the caldera has three pit craters across the summit area. Construction of Garet and other small cinder cones has left a crescent-shaped lake. The onset of eruptive activity from a vent high on the SE flank in 1962 ended a long period of dormancy.

Source: Vanuatu Meteorology and Geohazards Department (VMGD)