Report on Ambae (Vanuatu) — 18 April-24 April 2018
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 18 April-24 April 2018
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2018. Report on Ambae (Vanuatu). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 18 April-24 April 2018. Smithsonian Institution and US Geological Survey.
15.389°S, 167.835°E; summit elev. 1496 m
All times are local (unless otherwise noted)
Vanuatu Geohazards Observatory (VGO) reported that during April the eruption from a cone in Ambae’s Lake Voui continued through 23 April, with ash emissions and some lava fountaining. Ash, scoria, and acid rain fell on the island. Observations on 21 April confirmed that the cone had grown, and that the crater in the center of the cone was larger; a small lake was present in the crater. The Alert Level remained at 3 (on a scale of 0-5), and the report reminded residents to stay at least 3 km away from the active crater.
Geologic Background. 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.