Report on Ambrym (Vanuatu) — June 1991
Bulletin of the Global Volcanism Network, vol. 16, no. 6 (June 1991)
Managing Editor: Lindsay McClelland.
Ambrym (Vanuatu) Ash plume extends 50 km
Please cite this report as:
Global Volcanism Program, 1991. Report on Ambrym (Vanuatu). In: McClelland, L (ed.), Bulletin of the Global Volcanism Network, 16:6. Smithsonian Institution. https://doi.org/10.5479/si.GVP.BGVN199106-257040.
16.25°S, 168.12°E; summit elev. 1334 m
All times are local (unless otherwise noted)
The control tower at Bauerfield airport (serving Port Vila, ~150 km SSE of Ambrym), reported a 2-km-high ash cloud stretching ~50 km from Marum Crater on 10 June.
Geologic Background. Ambrym, a large basaltic volcano with a 12-km-wide caldera, is one of the most active volcanoes of the New Hebrides arc. A thick, almost exclusively pyroclastic sequence, initially dacitic, then basaltic, overlies lava flows of a pre-caldera shield volcano. The caldera was formed during a major plinian eruption with dacitic pyroclastic flows about 1900 years ago. Post-caldera eruptions, primarily from Marum and Benbow cones, have partially filled the caldera floor and produced lava flows that ponded on the caldera floor or overflowed through gaps in the caldera rim. Post-caldera eruptions have also formed a series of scoria cones and maars along a fissure system oriented ENE-WSW. Eruptions have apparently occurred almost yearly during historical time from cones within the caldera or from flank vents. However, from 1850 to 1950, reporting was mostly limited to extra-caldera eruptions that would have affected local populations.
Information Contacts: C. Mortimer, Dept of Geology, Mines, and Rural Water Supply, Vanuatu.