Report on Yasur (Vanuatu) — 16 January-22 January 2002
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 16 January-22 January 2002
Managing Editor: Gari Mayberry
Please cite this report as:
Global Volcanism Program, 2002. Report on Yasur (Vanuatu). In: Mayberry, G (ed.), Weekly Volcanic Activity Report, 16 January-22 January 2002. Smithsonian Institution and US Geological Survey.
19.532°S, 169.447°E; summit elev. 361 m
All times are local (unless otherwise noted)
Scientists were on alert for heightened volcanic activity at Yasur following a M 7.2 earthquake on 3 January at 0430 near Vanuatu. The earthquake produced landslides in Vanuatu's capital, Port Vila, and damaged buildings and bridges in the city, but there were no deaths or serious injuries. During 5 January to at least 16 January Yasur was active with ash falling on the population of Tanna Island, polluting water sources. The week of 6 January the Vanuatu government restricted access to the volcano's crater citing an increased risk of a large eruption since the 3 January earthquake. Authorities are prepared to evacuate residents from near the volcano if a large eruption occurs.
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.