Report on Heard (Australia) — 24 November-30 November 2021
Smithsonian / US Geological Survey Weekly Volcanic Activity Report,
24 November-30 November 2021
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2021. Report on Heard (Australia). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 24 November-30 November 2021. Smithsonian Institution and US Geological Survey.
53.106°S, 73.513°E; summit elev. 2745 m
All times are local (unless otherwise noted)
Thermal satellite images of Heard Island’s Big Ben volcano showed thermal anomalies of varying intensity over the summit area or on the NW and W flanks on 4, 11, 14, and 21 November. Weather clouds prevented views of the volcano on eight other acquisitions during the month. On 11 November four anomalies on the NW flank formed a “v” shape open to the NW, possibly indicating a branched lava flow. On 21 November the anomaly was on the W flank and possible emissions from the E and SE margins of it drifted SE.
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 historically 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.
Source: Sentinel Hub