Report on Ambae (Vanuatu) — 19 April-25 April 2023
Smithsonian Institution / US Geological Survey
Weekly Volcanic Activity Report, 19 April-25 April 2023
Managing Editor: Sally Sennert.
Please cite this report as:
Global Volcanism Program, 2023. Report on Ambae (Vanuatu) (Sennert, S, ed.). Weekly Volcanic Activity Report, 19 April-25 April 2023. Smithsonian Institution and US Geological Survey.
15.389°S, 167.835°E; summit elev. 1496 m
All times are local (unless otherwise noted)
Vanuatu Meteorology and Geo-Hazards Department (VMGD) reported that at 0730 on 19 April a plume consisting of steam, sulfur dioxide gas, and ash rose 695 m above Ambae’s summit and drifted E and SE, based on an image from a webcam located 22 km NE on the NE tip of Ambae Island, in Saratamata. The Alert Level remained at 2 (on a scale of 0-5) and the public was warned to stay outside of the Danger Zone, defined as a 2-km radius around the active vents in Lake Voui, and away from drainages during heavy rains.
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.