The Vanuatu Meteorology and Geo-hazards Department has issued Alert Bulletin No.13 yesterday on the Ambae Volcano.
The alert level for Ambae’s volcano has been lowered to Level 3 from Level 4.
Eruptive activity remains stable at Ambae.
The volcanic eruption at Ambae is continuing but remains stable and confined to Lake Voui.
Further scientific analyses confirm that there is currently no evidence of escalation of the activity. As a consequence, the Volcanic Alert Level is lowered by Vanuatu Meteorology and Geo-hazard Department (VMGD) to Level 3 from Level 4.
The volcanic eruption is likely to continue in a steady state. Danger is restricted to the danger zone that extends 3km from the active vent in Lake Voui.
Observation flights on September 30 and October 1, 3 and 5 confirm the activity at the volcano is only occurring in one of the summit crater lakes (Lake Voui) and is not changing.
Photographs and thermal infrared images taken during observation flights show the activity consists of small explosions and ejection of hot rocks from vents on the new small island in the lake. There is also a small lava flow from the island into the lake. A small-scale eruption continues in Lake Voui at Ambae volcano.
These observations and the analysis of seismic, gas and deformation data by scientists from the Geohazards Division of the Vanuatu Meteorology and Geohazard Department and international scientists confirms that the volcano has settled in a more stable state of activity.
The activity at Ambae is like what is seen and experienced at Yasur on Tanna Island. The local population can hear some of the explosions and see glow over the mountain at night.
The eruption at Ambae started in September, when the Volcanic Alert Level was raised to Level 3. The volcanic activity has built a volcanic cone (island) in Lake Voui. The cone building phase produced the largest explosions and ashfalls. Some parts of the island experienced ashfalls from this phase of the eruption. The eruptions in mid-September 2017 are similar to those in 2005.
The style of the eruption changed around 22 September when Geohazards staff observed lava (molten rock) at the surface for the first time. This was a significant change and raised the level of uncertainty about the development of the eruption. The volcanic Alert Level was also raised at that time to Level 4.
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 1670s 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.
The danger zone is now within 3 km from the vent in Lake Voui. In this area flying rock and volcanic gases may be present. Villages located further away may experience volcanic hazards from gas plumes, especially villages exposed to prevailing trade winds direction.
The VMGD will continue to closely monitor this volcano activity. More information will be provided as available.