The Wellington VAAC reported that during 27-28 December ash emissions from Yasur were visible in webcam images rising above the crater rim, to 1.5 km (5,000 ft) a.s.l. Plumes containing ash were not visible in satellite images, though they were also confirmed by Vanuatu Meteorology and Geohazards Department (VMGD).

Geological Summary. Yasur has exhibited essentially continuous Strombolian and Vulcanian activity at least since Captain Cook observed ash eruptions in 1774. This style of activity may have continued for the past 800 years. Located at the SE tip of Tanna Island in Vanuatu, this pyroclastic cone has a nearly circular, 400-m-wide summit crater. The active cone is largely contained within the small Yenkahe caldera, and is the youngest of a group of Holocene volcanic centers constructed over the down-dropped NE flank of the Pleistocene Tukosmeru volcano. The Yenkahe horst is located within the Siwi ring fracture, a 4-km-wide open feature associated with eruption of the andesitic Siwi pyroclastic sequence. Active tectonism along the Yenkahe horst accompanying eruptions has raised Port Resolution harbor more than 20 m during the past century.

Source: Wellington Volcanic Ash Advisory Center (VAAC)