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Report on Whakaari/White Island (New Zealand) — June 1982

Whakaari/White Island

Scientific Event Alert Network Bulletin, vol. 7, no. 6 (June 1982)
Managing Editor: Lindsay McClelland.

Whakaari/White Island (New Zealand) Localized inflation; no eruptive activity

Please cite this report as:

Global Volcanism Program, 1982. Report on Whakaari/White Island (New Zealand) (McClelland, L., ed.). Scientific Event Alert Network Bulletin, 7:6. Smithsonian Institution. https://doi.org/10.5479/si.GVP.SEAN198206-241040

Whakaari/White Island

New Zealand

37.52°S, 177.18°E; summit elev. 294 m

All times are local (unless otherwise noted)

NZGS personnel visited White Island on 1 June. No significant eruptive activity had occurred since January, but fumarolic activity in 1978 Crater appeared more intense. Vents on the walls and floor of the active subcrater emitted large white steam columns, and numerous small geysers jetted black muddy water. Rockfalls from the W wall had formed a fan onto the subcrater floor. A green lake occupied much of the SE sector of the subcrater floor.

Inflation localized around Donald Mound (a 100 x 150 m area in the middle of the main crater and ~150 m E of the edge of 1978 Crater) had continued, with a rise of 13 mm measured ~50 m to the E, and 18 mm about 100 m to the SE. The inflation started a year ago, but paused between September and December, 1981. Fumaroles near the Mound and about 200 m N of it were emitting large white steam columns. Fumarole temperatures around Donald Mound showed a general increase from 630°C on 2 December 1980, to 650°C in May 1981 and January 1982, and 690°C in June 1982. More sulfur appeared to have been deposited at the ground surface. For the area between 1978 Crater and Donald Mound and extending about 200 m to the N, magnetometer data showed increases in total magnetic field of between 64 and 326 nanoteslas (nT), compared to changes of less than 25 nT over the rest of the main crater since January.

Between 27 February and 2 June, more than 150 (and occasionally as many as 400) usually small, low-frequency (B-type) events were recorded per day during three periods of increased seismicity: 15-20 March, 26 March-8 April, and 22 May. No more than 39 low-frequency events were recorded on other days. High-frequency (volcano-tectonic) events usually numbered fewer than 5/day except for 6 on 4 and 13 March, 44 on 3 April, and 6 on 2 June. Volcanic tremor was recorded on 25-26 March, and 5 and 12 May.

Geological Summary. The uninhabited Whakaari/White Island is the 2 x 2.4 km emergent summit of a 16 x 18 km submarine volcano in the Bay of Plenty about 50 km offshore of North Island. The island consists of two overlapping andesitic-to-dacitic stratovolcanoes. The SE side of the crater is open at sea level, with the recent activity centered about 1 km from the shore close to the rear crater wall. Volckner Rocks, sea stacks that are remnants of a lava dome, lie 5 km NW. Descriptions of volcanism since 1826 have included intermittent moderate phreatic, phreatomagmatic, and Strombolian eruptions; activity there also forms a prominent part of Maori legends. The formation of many new vents during the 19th and 20th centuries caused rapid changes in crater floor topography. Collapse of the crater wall in 1914 produced a debris avalanche that buried buildings and workers at a sulfur-mining project. Explosive activity in December 2019 took place while tourists were present, resulting in many fatalities. The official government name Whakaari/White Island is a combination of the full Maori name of Te Puia o Whakaari ("The Dramatic Volcano") and White Island (referencing the constant steam plume) given by Captain James Cook in 1769.

Information Contacts: I. Nairn, C. Wood, and B. Scott, NZGS, Rotorua; P. Otway, NZGS, Wairakei; D. Sheppard, DSIR, Gracefield.