Report on Whakaari/White Island (New Zealand) — January 1981
Scientific Event Alert Network Bulletin, vol. 6, no. 1 (January 1981)
Managing Editor: Lindsay McClelland.
Whakaari/White Island (New Zealand) Ash, impact craters, gas clouds, seismicity
Please cite this report as:
Global Volcanism Program, 1981. Report on Whakaari/White Island (New Zealand) (McClelland, L., ed.). Scientific Event Alert Network Bulletin, 6:1. Smithsonian Institution. https://doi.org/10.5479/si.GVP.SEAN198101-241040.
37.52°S, 177.18°E; summit elev. 294 m
All times are local (unless otherwise noted)
NZGS personnel flew over White Island on the morning of 6 January. In the 10 minutes they were over the island, the voluminous convoluting emissions of white steam and gas clouds obscured their view around and into 1978 Crater. The lower portion of the 600-750-m-high eruption column was slightly ash-charged. The main crater was thickly covered with eroded brown-green ash. Impact craters extended a few hundred meters NE from 1978 Crater. Conspicuous blue fumes were associated with the steam-gas column rising in the 1914 landslide area just SE of 1978 Crater.
Seismicity since ground inspections in early December was characterized by four distinct periods of marked increase. Intervals of high-frequency, high-amplitude tremor were recorded for 32 hours on 15-16 December, for 35 hours on 22-23 December, and for 26 hours on 27-28 December. Strong ash emissions were likely during these periods. Large discrete earthquakes were recorded on 14 December and 2 January.
Geologic Background. 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: B. Scott, NZGS, Rotorua.