Report on Deception Island (Antarctica) — March 1993
Bulletin of the Global Volcanism Network, vol. 18, no. 3 (March 1993)
Managing Editor: Edward Venzke.
Deception Island (Antarctica) Activity declines from last year's levels
Please cite this report as:
Global Volcanism Program, 1993. Report on Deception Island (Antarctica). In: Venzke, E. (ed.), Bulletin of the Global Volcanism Network, 18:3. Smithsonian Institution. https://doi.org/10.5479/si.GVP.BGVN199303-390030.
63.001°S, 60.652°W; summit elev. 602 m
All times are local (unless otherwise noted)
Activity has declined from the more vigorous behavior seen during the 1991-92 survey to levels recorded during earlier surveys. Only 135 seismic events (M 0.3-0.9) were recorded compared to the 766 events detected during the 1991-92 survey. Episodes of tremor in the NW sector of the island were recorded on 1 January, 2 February, and 16 February 1993. Five deep (55-85 km) earthquakes, M 1.6-2.4, were detected.
Fumaroles emitted mainly CO2 (87-98%) and H2S (1.8-13%); no SO2 was detected. Dry-tilt measurements of 600 µrads uplift at Fumarole Bay indicated a slight elevation of the entire fumarolic area. Temperature measurements made by the Spanish Oceanographic Ship "Hespérides" showed a decrease in the intensity of the submarine emissions in Port Foster Bay since the 1990-91 survey.
Geologic Background. Ring-shaped Deception Island, one of Antarctica's most well known volcanoes, contains a 7-km-wide caldera flooded by the sea. Deception Island is located at the SW end of the Shetland Islands, NE of Graham Land Peninsula, and was constructed along the axis of the Bransfield Rift spreading center. A narrow passageway named Neptunes Bellows provides entrance to a natural harbor that was utilized as an Antarctic whaling station. Numerous vents located along ring fractures circling the low, 14-km-wide island have been active during historical time. Maars line the shores of 190-m-deep Port Foster, the caldera bay. Among the largest of these maars is 1-km-wide Whalers Bay, at the entrance to the harbor. Eruptions from Deception Island during the past 8700 years have been dated from ash layers in lake sediments on the Antarctic Peninsula and neighboring islands.
Information Contacts: R. Ortiz, Museo Nacional de Ciencias Naturales, Spain; C. Risso, Instituto Antártico Argentino.