Increased volcanic activity at Yasur volcano, Vanuatu

Volcanic activity at Yasur volcano, Vanuatu continues at the major unrest state with ongoing volcanic gases and ashes emissions and an increase in activity recorded on December 18, 2021. The Volcanic Alert Level remains at Level 2.

The latest data analysis indicates that volcanic activity at Yasur is currently high in the level of major unrest state, the Vanuatu Meteorology and Geohazards Department (VMGD) reported on December 19.¹

An increase in activity was recorded on December 18 around 21:00 LT and was confirmed by observations data of bombs ejected from the vent to the volcano cone.

Images courtesy VMGD

This means that the level of risk for visitors accessing areas within the Danger Zone A (areas around the crater rim to the parking) REMAIN HIGH. Areas and villages located close to the volcano may continue to expect volcanic gases impacts and/or ash falls following wind directions.

It is useful to remind that all tourism agencies, visitors, local authorities, people from Tanna Island, and the general public take this information into consideration, VMGD said.

VMGD and the Wellington VAAC reported multiple gas-and-ash emissions since November 27.

Yasur volcano on November 1, 2021. Credit: Copernicus EU/Sentinel-2, TW

Geological Summary

Yasur, the best-known and most frequently visited of the Vanuatu volcanoes, has been in more-or-less continuous strombolian and vulcanian activity 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, this mostly unvegetated pyroclastic cone has a nearly circular, 400 m (1 312 feet) wide summit crater.

Yasur 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 (2.5 miles) wide, horseshoe-shaped caldera 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 (65 feet) during the past century.²

References:

¹ Update on Yasur volcano activity issued by the Vanuatu Meteorology and Geohazards Department on 19th December 2021 at 6:56pm

² Yasur – Geological summary – GVP

Featured image credit: VMGD