Report on Yasur (Vanuatu) — 10 March-16 March 2010
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 10 March-16 March 2010
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2010. Report on Yasur (Vanuatu). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 10 March-16 March 2010. Smithsonian Institution and US Geological Survey.
19.532°S, 169.447°E; summit elev. 361 m
All times are local (unless otherwise noted)
On 12 March, Vanuatu Geohazards Observatory reported that thermal anomalies from Yasur were detected in satellite imagery during 8 December 2009-8 March 2010. They also noted an increase in activity since January 2010. Satellite images from 21 January showed significant sulfur dioxide gas emissions. Bombs were ejected sometime during the week of 1 March. Observations on 8 March and analyses of seismic data also indicated increased activity, and all three vents were active. The Vanuatu Volcano Alert Level (VVAL) was raised to 2 (on a scale of 0-4).
Geologic Background. Yasur, the best-known and most frequently visited of the Vanuatu volcanoes, has been in more-or-less continuous Strombolian and Vulcanian activity since Captain Cook observed ash eruptions in 1774. This style of activity may have continued for the past 800 years. Located at the SE tip of Tanna Island, this mostly unvegetated pyroclastic cone has a nearly circular, 400-m-wide summit crater. The active cone is largely contained within the small Yenkahe caldera, and is the youngest of a group of Holocene volcanic centers constructed over the down-dropped NE flank of the Pleistocene Tukosmeru volcano. The Yenkahe horst is located within the Siwi ring fracture, a 4-km-wide, horseshoe-shaped caldera associated with eruption of the andesitic Siwi pyroclastic sequence. Active tectonism along the Yenkahe horst accompanying eruptions has raised Port Resolution harbor more than 20 m during the past century.