Report on Yasur (Vanuatu) — 31 March-6 April 2004

Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 31 March-6 April 2004
Managing Editor: Gari Mayberry

Please cite this report as:

Global Volcanism Program, 2004. Report on Yasur (Vanuatu). In: Mayberry, G (ed.), Weekly Volcanic Activity Report, 31 March-6 April 2004. Smithsonian Institution and US Geological Survey.

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Yasur

Vanuatu

19.532°S, 169.447°E; summit elev. 361 m

All times are local (unless otherwise noted)


According to a report from John Seach, eruptive activity at Yasur continued at "normal" levels during March, with an average of 500 explosions occurring per day.

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.

Source: Volcano Live