Report on Ambae (Vanuatu) — 6 September-12 September 2017
Smithsonian Institution / US Geological Survey
Weekly Volcanic Activity Report, 6 September-12 September 2017
Managing Editor: Sally Sennert.
Please cite this report as:
Global Volcanism Program, 2017. Report on Ambae (Vanuatu) (Sennert, S, ed.). Weekly Volcanic Activity Report, 6 September-12 September 2017. Smithsonian Institution and US Geological Survey.
15.389°S, 167.835°E; summit elev. 1496 m
All times are local (unless otherwise noted)
On 30 August the Vanuatu Geohazards Observatory (VGO) stated that conditions at Aoba had been changing, increasing the potential for eruptive activity. On 6 September a VGO report noted that activity continued to increase; the Alert Level was raised to 3 (on a scale of 0-4) signifying that the volcano is in a minor eruption phase. VGO reminded residents and tourists not to approach the volcano within a 3-km radius, and to stay out of areas subject to trade-wind exposure.
Geological Summary. The island of Ambae, also known as Aoba, is a massive 2,500 km3 basaltic shield that is the most voluminous volcano of the New Hebrides archipelago. A pronounced NE-SW-trending rift zone dotted with scoria cones gives the 16 x 38 km island an elongated form. A broad pyroclastic cone containing three crater lakes (Manaro Ngoru, Voui, and Manaro Lakua) is located at the summit within the youngest of at least two nested calderas, the largest of which is 6 km in diameter. That large central edifice is also called Manaro Voui or Lombenben volcano. Post-caldera explosive eruptions formed the summit craters about 360 years ago. A tuff cone was constructed within Lake Voui (or Vui) about 60 years later. The latest known flank eruption, about 300 years ago, destroyed the population of the Nduindui area near the western coast.