Report on Yasur (Vanuatu) — March 2004

Bulletin of the Global Volcanism Network, vol. 29, no. 3 (March 2004)
Managing Editor: Richard Wunderman

Yasur (Vanuatu) 500 explosions/day in March 2004; MODIS thermal alerts average about one per month

Please cite this report as:

Global Volcanism Program, 2004. Report on Yasur (Vanuatu). In: Wunderman, R (ed.), Bulletin of the Global Volcanism Network, 29:3. Smithsonian Institution. http://dx.doi.org/10.5479/si.GVP.BGVN200403-257100.

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Yasur

Vanuatu

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

All times are local (unless otherwise noted)


Activity from the summit crater at Yasur continued through 2002 (BGVN 28:01). While similar comprehensive reports are not available for 2003, MODIS data (table 2) indicated activity continuing over the year to 16 March 2004. No corroborative reports of activity have been received from the Rabaul Volcano Observatory or the Darwin Volcanic Ash Advisory Centre.

Table 2. Nights on which MODIS thermal alerts were recorded for Yasur during the year ending 16 March 2004. Data courtesy HIGP MODIS Thermal Alert System.

[Skip text table]
    Month       Days with Thermal Alerts

    Mar 2003    23
    Apr 2003    15
    May 2003    3,10
    Jun 2003    4
    Sep 2003    8,17
    Oct 2003    17, 24, 26
    Nov 2003    5, 10, 12
    Mar 2004    13

John Seach reported continued eruptions at Yasur during March 2004. He suggested that there was an average of about 500 explosions per day, which is typical of the volcano's normal state of activity.

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: HIGP MODIS Thermal Alert System, Hawaii Institute of Geophysics and Planetology, School of Ocean and Earth Science and Technology, University of Hawaii at Manoa (URL: http://modis.higp.hawaii.edu/); John Seach, PO Box 4025, Port Vila, Vanuatu (Email: john@volcanolive.com, URL: http://www.volcanolive.com/).