Vanuatu Volcano Alert Bulletin n°6 - Ambae Activity (10 July 2018)



Tuesday July 10th 2018

15°24’0”S 167°50’0”E Summit 4908ft (1496m)
Current Vanuatu Volcano Alert Level:** Level 2**

Ambae volcano is continuing in the major unrest state. The Volcanic Alert Level remains at Level 2.

Volcanic unrest is continuing at Ambae. The current volcanic activity is consistent with Volcanic Alert Level 2. The Danger Zone for life safety is limited at 2 km radius from the active vent and areas located in the Yellow Zone (See Map below).

Observations in June 2018 confirm that the Ambae volcano activity is not stable since 20th June; on the 1st of July, the volcano emitted a column of ash which induced heavy to light ash fall at villages especially from North-West to West of Ambae Island and also the North-Eastern part of Santo Island driven by the prevailing trade wind. A small eruption scale in Lake Voui is continuing.

The presence of ash that has fallen on Ambae during the last eruptive phases will continue to change the behavior of streams and creeks when it rains. The creeks and streams can 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 continuing in the major unrest state. The volcano activity consist of ongoing emission of steam and/or gases and sometimes ashes. The local population from Ambae and from neighboring island can hear rumbling from volcano, see volcanic ash and gas plume and glows over the mountain at night.

Significant impact of ashes and gases emission to villages at Ambae started in March, when the Volcanic Alert level was raised to Level 3. Observations of the current activity are consistent with the Alert Level 2 activity. Level 2 indicates _‘Major unrest; Danger is now at 2 km around the volcanic vents and areas inside the Yellow Zone’ _. **The possibility that the Ambae volcano activity escalate to the level of minor eruption is low to moderate **.

Ambae volcano is a very large volcano and is frequently active. A large-scale eruption about 400 years ago built a volcanic cone in the summit crater and the crater is now filled by Lake Voui; the modern active vent area underlies Lake Voui. Historic activity is poorly known, but there is documented activity in 1530, 1670, 1870, 1915 and 1966. All documented activity has been from the summit crater (Lake Voui) except for the 1670 activity, which included a flank eruption producing lava flows at Ndui Ndui. The current eruption episode started in 1991, with eruptions in 1995, 2005, 2016 and 2017. The current eruption is focused in the summit crater and there are no indications of activity elsewhere on Ambae Island for now.

Advise to all tourism agencies, local authorities, people of Ambae and the general public **not to access the Danger Zone which is about 2 km radius from the eruptive vents. Volcanic gases and ashes are expected in this area. Villages in the Yellow Color may continue to expect change in streams and creeks flows during rain fall **(See map below). Villages from Ambae island may experience impacts of volcanic gases and ashes especially those exposed to prevailing trade winds direction. _(Please see the Volcano key Messages at the link below): _.

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

For further information, please contact Geohazards Division at the Vanuatu Meteorology and Geohazards Department at or 24686.