Vanuatu Volcano Alert Bulletin n°3 - Ambae Activity (4 April 2018)

Situation Report
Originally published
View original


Ambae volcano is continuing in the minor eruption state; Its Volcanic Alert Level remains at Level 3 .

The volcanic eruption at Ambae confined inside the Lake Voui is stable at Alert Level 3. The volcanic activity is likely to remain at the minor eruptive activity or decrease to a major level of unrest at any time. The restricted area of risk is limited to the area of 3 km from the active vent and areas located in the Yellow Zone (See Map below).

Observations of March and early April 2018 confirm that the Ambae eruption style has changed, the volcano emitted more and sustained volcanic ash or/and gases. The presence of accumulated ash that is falling around the volcanic area could change the behaviour of streams and creeks when it rains. The creeks and streams could produce floods and carry a lot more debris (sands, gravel and boulders). The flow path of streams and creeks could change due to the flood debris. Landslide may occur at some areas during heavy rain fall.

These observations and the analysis of seismic data confirm that the volcano activity is in the level of minor eruption state. The volcano activity consist of ongoing emission of ashes, gases and volcanic bombs.

Based on its slight decreased seismic activity and observation of ongoing volcanic gas emission and steam plumes on the web camera, the Volcanic Alert Level (VAL) at Ambae was dropped to Level 2 on 7th December 2017. The current activity shows ongoing ashes and gases emission causing more impact to villages. This is consistent with the Alert Level 3 activity. Level 3 indicates ‘Minor eruption; Danger is now at 3 km around the volcanic vent and areas that exposed to the wind direction’ . The possibility that the Ambae volcano activity escalate to the level of moderate eruption is low .

Ambae volcano is a very large volcano and is frequently active. In the recorded history, there have been many eruptions, every 10-50 years over the past 150 years. All have been from the summit craters, except one recorded in 1670’s when a lava flow occurred in the Ndui Ndui area. The current eruption is focused in the summit crater and there are no indications of activity elsewhere on Ambae Island.

Advise to all tourism agencies, local authorities, people of Ambae and the general public not to access the Danger Zone which is about 3 km radius from the eruptive vents. Volcanic gases, ashes and projectiles are expected in this area . Villages in the Yellow color may expect occurrence of dangerous flow (See map below). Villages from Ambae island may experience impacts of volcanic gases, ashes and acid rain especially those exposed to prevailing trade winds direction . (Please see Volcanic Gas, Ashes and Acid Rain key messages at this link : ) .

The Vanuatu Meteorology and Geohazards Department will continue to closely monitor this volcano activity. More information will be provided as available.