No further reports of volcanic activity on this remote, uninhabited island were received until 29 September, when scientists from the MV Nella Dan (ship) observed steam rising from a vertical crack in the Gotley Glacier (on the SW flank). On 4 October at about 2100, from 11.5 km offshore, two distinct areas of glow were observed: at the summit, and at a point between 1,500 and 2,000 m altitude in Gotley Glacier, 6.5-7 km from the summit. The observers believed the flank glow to be a second source of lava, although they noted the possibility that lava originating at the summit might have flowed under the glacier and emerged at that point. Space Shuttle astronauts observed the volcano emitting vapor every day during their 30 October-5 November mission and took a photograph (no. 61A-49-047), but there was no sign of fresh lava or ash on the summit.

Further Reference. Quilty, P., 1985, New volcanic vent on Heard Island?: ANARE News, December. 1985, p. 11.

Geological Summary. 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 lies at the NW tip of the island across a narrow isthmus. Little is known about the structure of Big Ben because of its extensive ice cover. The active Mawson Peak forms the island's 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 at this isolated volcano, but observations are infrequent and additional activity may have occurred.

Information Contacts: R. Varne, Univ. of Tasmania; M. Helfert, NASA.