BackgroundHeard 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.
Smithsonian / GVP volcano information
Acid water can be heard bubbling beneath the surface in one of the springs at Dallol hydrothermal field, Ethiopia. (Photo: Tom Pfeiffer)
As we arrive on Belvedere at around 1pm the New SE crater and the old SE crater behind are still quiet, but soon, the first explosions can be heard from a vent inside the...
Heard Island volcano in eruption with dark lava flows on the snow, Nov 2015 (Photo: Richard Arculus)
Unusually clear view of the interior of the NE crater. Every few minutes, detonations from deep-seated explosions can be heard (and felt). (Photo: Tom Pfeiffer)
See also: Sentinel hub | Landsat 8 | NASA FIRMS