Volcano Type: Stratovolcano
Volcano Status: Historical
Last Known Eruption: 2008
Summit Elevation: 2745 m 9,006 feet
Latitude: 53.106°S 53°6’20″S
Longitude: 73.513°E 73°30’45″E
Heard Island on the Kerguelen Plateau in the southern Indian Ocean consists primarily of the emergent portion of two volcanic structures. The large glacier-covered composite basaltic-to-trachytic cone of Big Ben comprises most of the island, and the smaller Mt. Dixon volcano lies at the NW tip of the island across a narrow isthmus. Little is known about the structure of Big Ben volcano because of its extensive ice cover. The historically active Mawson Peak forms the island’s 2745-m high point and lies within a 5-6 km wide caldera breached to the SW side of Big Ben. Small satellitic scoria cones are mostly located on the northern coast. Several subglacial eruptions have been reported in historical time at this isolated volcano, but observations are infrequent and additional activity may have occurred.
Heard Island
Heard Island is located 4000 kilometres southwest of Western Australia and contains one of Australia’s two currently active volcanoes. Volcanic activity has been reported at the island since the 1980′s. Heard Island covers an area of 368 sq km. Mawson Peak at 2745 m is the highest mountain on Australian territory, outside Australian Antarctic Territory.
Aerial view of Heard Island
Heard Island is located in the `Furious Fifties’ , where strong winds blow mainly from the west. A mean sea-level wind speed of 26 km/h and a maximum gust of 209 km/h were recorded between December 1947 and March 1955, when an Australian base was maintained at Atlas Cove on the western side of Big Ben. Heard Island sits on the submarine Kerguelen Plateau, which rises 3700 m above the sea floor, and deflects Antarctic circumpolar bottom water northward past Kerguelen Islands. The McDonald Island group lies 43.5 km west of Heard Island, and consists of McDonald Island (area 1 sq km), and the much smaller Flat Island and Meyer Rock.
Originally posted 2010-08-30 04:42:00.
