Gaua (Vanuatu)

Status Unrest Eruption 2011 797m
Stratovolcano (Subduction zone / Intermediate crust (15-25 km))

Gaua

The roughly 20-km-diameter Gaua Island, also known as Santa Maria, consists of a basaltic-to-andesitic stratovolcano with an 6 x 9 km wide summit caldera. Small parasitic vents near the caldera rim fed Pleistocene lava flows that reached the coast on several sides of the island; several littoral cones were formed where these lava flows reached the sea. Quiet collapse that formed the roughly 700-m-deep caldera was followed by extensive ash eruptions. Construction of the historically active cone of Mount Garat (Gharat) and other small cinder cones in the SW part of the caldera has left a crescent-shaped caldera lake. The symmetrical, flat-topped Mount Garat cone is topped by three pit craters. The onset of eruptive activity from a vent high on the SE flank in 1962 ended a long period of dormancy.

A steam plume rises from the historically active crater of Mount Garat in this view across Lake Letas, within the 6 x 9 km wide summit caldera of Gaua volcano (also known as Santa Maria). Construction of Mount Garat (Gharat) and other small cinder cones in the SW part of the caldera left this crescent-shaped caldera lake. The symmetrical, flat-topped Mount Garat cone is topped by three craters. The onset of eruptive activity from a vent high on the SE flank of Mount Garat in 1962 ended a long period of dormancy.

Photo by John Seach, 1999.

Last updated 2019-12-16 19:00:04

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