Volcano Type: Stratovolcano
Volcano Status: Historical
Last Known Eruption: 2010
Summit Elevation: 797 m 2,615 feet
Latitude: 14.27°S 14°16’0″S
Longitude: 167.50°E 167°30’0″E
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 of Mount Garat in 1962 ended a long period of dormancy.
Around the volcano
Gaua is a large shield volcano with gentle outer slopes, a large caldera lake (Lake Letas), and summit cinder cone (Mt Garet). The caldera is 8 x 6 km in diameter. Lake Letas occupies half the caldera with an area of 19.7 sq km. It is about 100 m deep and flat bottomed. There is warm, sulphur stained water near Mt Garet cone. Gaua Island lies just north of the Santa Maria Fracture Zone, which runs perpendicular to the north New Hebrides Trench.
Originally posted 2010-08-20 04:59:37.
