Report on Whakaari/White Island (New Zealand) — January 1989
Scientific Event Alert Network Bulletin, vol. 14, no. 1 (January 1989)
Managing Editor: Lindsay McClelland.
Whakaari/White Island (New Zealand) Vulcanian explosions; new crater
Please cite this report as:
Global Volcanism Program, 1989. Report on Whakaari/White Island (New Zealand) (McClelland, L., ed.). Scientific Event Alert Network Bulletin, 14:1. Smithsonian Institution. https://doi.org/10.5479/si.GVP.SEAN198901-241040.
37.52°S, 177.18°E; summit elev. 294 m
All times are local (unless otherwise noted)
No unusual activity had been reported in the month following 2 December fieldwork. On 4 January, tourists found a few small lava bombs near the 1978 Crater rim. The previously active (Hitchhiker) vent emitted a pink plume containing fine ash. Between the 4th and the next visit at about 0800 on 12 January, a new pit vent had formed S of Congress Crater in 1978 Crater (figure 10). Both the new vent (named R.F.) and Hitchhiker vent emitted white steam plumes. At 1000, an incandescent jet was noted in the Blue Duck fumarole area, 200 m away.
|Figure 10. Location of the new R.F. vent and height changes (in mm) at White Island, 15 June-2 December 1988. Courtesy of NZGS.|
When geologists visited the crater on 14 January, the new vent was emitting voluminous clouds of light brown-red ash and appeared to be ~40 m in diameter. At 1039, a discrete eruption ejected a convoluting ash column to 1,500 m. Ash fell E into the sea. There was no emission from Hitchhiker vent. Light red-brown ash coated the E end of the island and reached 17 cm thickness at the 1978 Crater rim. Fumarole temperatures were similar to those measured 2 December. A vent (N of Fumarole 6) that had enlarged to 2 m in diameter and was surrounded by small blocks, may have been the source of the small eruption seen 12 January. Several similar eruptions were observed from Whakatane (50 km SSW) 14 and 15 January. The 12-14 January eruptions were among the largest since 1980.
Only limited seismic data were available after 2 December. Early December seismic records were dominated by weak, continuous, medium- to high-frequency volcanic tremor and small A-type volcanic events. After 4 January, microearthquake activity declined to a maximum of ~2,500/day, B-type events were rare, and A-types increased. Explosion earthquakes were registered 4 December and 7 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 and I. Nairn, NZGS Rotorua.