The Extinction Protocol
Tue, 02 Oct 2012 09:06 CDT
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. The last eruptive activity occurred at the volcanic complex in 2008. However, MODIS satellite data showed hotspots at Heard Island volcano on 21 and 24 September 2012. This suggests that there was or perhaps still is some new activity at the volcano. No further hotspots appeared on satellite data since September 24. - Volcano Discovery