Report on Whakaari/White Island (New Zealand) — May 2000
Bulletin of the Global Volcanism Network, vol. 25, no. 5 (May 2000)
Managing Editor: Richard Wunderman.
Whakaari/White Island (New Zealand) April-May seismicity and emissions appear independent
Please cite this report as:
Global Volcanism Program, 2000. Report on Whakaari/White Island (New Zealand) (Wunderman, R., ed.). Bulletin of the Global Volcanism Network, 25:5. Smithsonian Institution. https://doi.org/10.5479/si.GVP.BGVN200005-241040.
37.52°S, 177.18°E; summit elev. 294 m
All times are local (unless otherwise noted)
Staff from the New Zealand Institute of Geological & Nuclear Sciences (GNS) visited White Island on 8 June to assess the volcano status and do routine seismograph maintenance. The level of activity was similar to that reported over the last two months (BGVN 25:03 and 25:04). The MH-vent was producing a weak gas-and-ash plume, which was rising 800-1000 m before being blown to the NNW. The plume was visible 20-30 km from the island as a lightly colored haze.
Seismic activity had declined almost to background levels. Seismicity started to increase about 5 April, peaked about 12 May, and subsequently declined. Meanwhile, the nature and intensity of the eruptive activity had not changed significantly, confirming earlier assessments that no direct relationship existed between the intensity of the eruptive activity at MH-vent and the level of seismic activity.
White Island has now been at Alert Level 2 for ~50 days. While the intensity of the activity has varied slightly over this period, ash emission has occurred almost continuously and fresh ash now covers the island at thicknesses ranging from several millimeters to several centimeters. The style of eruptive activity has not changed during this time. The height of the ash-and-steam plume has varied with eruption intensity and wind strength, but 800-1000 m has been typical.
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: Brad Scott and Steven Sherburn, Wairakei Research Center, Institute of Geological and Nuclear Sciences (IGNS), Private Bag 2000, Wairakei, New Zealand (URL: http://www.gns.cri.nz/).