OCHA Situation Update No. 1 on Gaua Island Volcanic Activity, Vanuatu

1. Summary of the Situation

Gaua volcano on Gaua Island, TORBA Province, Vanuatu, has erupted on 18 November 2009. This explosion has been followed by very thick and high emissions of ash columns that were covering the areas exposed to trade winds in the West. Until present, the activity of Gaua volcano remains significant according to the Geo-Hazard Section, Department of Geology, Mines and Water Resources. It is recommended that the alert level of the volcano be maintained at level 2 while close monitoring of the volcanic activities is on-going. The probability of the volcanic activity going up to level 3 is low to moderate. Level 2 requires on- island evacuation mainly from the West to the East while Level 3 requires evacuation of the whole island population, which is estimated to be 3,000.

The danger persists almost on the entire island except the South-Western part. The North- Western part of the island is particularly at risk of ash fall and volcanic degassing while the eastern part is prone to lahar flow, especially along the area of Waterfall which is a lahar flow path. An area of at least 1 kilometre surrounding the river is highly prone to mudflow. The areas further away from the river of Waterfalls are also threatened with mudflow hazard in case of a highly explosive eruption, at least 6 kilometres north and south from the Waterfall River, which covers from Losalava to Makeliu Village. (Refer to the Gaua Hazard Map November 2009 P5 of Bulletin No 3, Gaua Volcano activity Gaua Island, 24 November 2009, Department of Geology, Mines and Water Resources).