Report on Yasur (Vanuatu) — July 1991
Bulletin of the Global Volcanism Network, vol. 16, no. 7 (July 1991)
Managing Editor: Lindsay McClelland.
Yasur (Vanuatu) Continued block and ash emissions; small episodic lava lakes
Please cite this report as:
Global Volcanism Program, 1991. Report on Yasur (Vanuatu). In: McClelland, L (ed.), Bulletin of the Global Volcanism Network, 16:7. Smithsonian Institution. http://dx.doi.org/10.5479/si.GVP.BGVN199107-257100.
19.532°S, 169.447°E; summit elev. 361 m
All times are local (unless otherwise noted)
"Activity remained unchanged during 1990-91, with block and ash emissions and small episodic lava lakes."
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.
Information Contacts: C. Robin and M. Monzier, ORSTOM, New Caledonia; M. Lardy and C. Douglas, ORSTOM, Vanuatu; C. Mortimer, Dept of Geology, Mines, and Rural Water Supply, Vanuatu; J. Eissen, ORSTOM, France.