Report on Whakaari/White Island (New Zealand) — June 2007
Bulletin of the Global Volcanism Network, vol. 32, no. 6 (June 2007)
Managing Editor: Richard Wunderman.
Whakaari/White Island (New Zealand) Falling water level in the crater lake, but no volcanic activity
Please cite this report as:
Global Volcanism Program, 2007. Report on Whakaari/White Island (New Zealand) (Wunderman, R., ed.). Bulletin of the Global Volcanism Network, 32:6. Smithsonian Institution. https://doi.org/10.5479/si.GVP.BGVN200706-241040.
37.52°S, 177.18°E; summit elev. 294 m
All times are local (unless otherwise noted)
According to Tony Hurst, reporting in the GNS Science Alert Bulletin of 6 March 2007, GeoNet conducted a visit to White Island on 23 February 2007 and found that the water level in the crater lake had fallen by 1.2 m in 10 days. The lake was 9 m below the overflow level, the result of rapid evaporation, with the lake temperature measured at 74°C. The falling level has reduced the area of the lake by about 10%, and volume by 20%, but there have been no indications of volcanic activity. However, the falling water level could reduce the pressure in the geothermal system, resulting in local boiling events at depth in the lake, and producing transient steam plumes.
Another Alert Bulletin prepared by Brad Scott on 3 May 2007 noted that the Alert Level for White Island remained at 1. The rapid decrease in the level of the crater lake seen over the last few months has continued. Recent observations confirmed that the lake was more than 28 m below overflow level, and the depth of water in the lake was likely to be about 10 m. The lake level fell very rapidly during April, significantly decreasing both the area and volume of the lake. The temperature of the lake declined from 74 to 64°C, probably due to less input from high-temperature steam vents, which are now above the lake. As the water level fell, many steam vents and fumaroles were exposed, producing transient steam plumes as high as 3 km sometimes mistaken as eruptions. However, no eruptions have occurred, and no changes in any of the monitoring data indicate potential increases in volcanic activity in the near future.
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: GeoNet, a collaboration between the Earthquake Commission and GNS Science (URL: http://www.geonet.org.nz/); GNS Science, Wairakei Research Center, Private Bag 2000, Taupo 3352, New Zealand (URL: http://www.gns.cri.nz/); Earthquake Commission (EQC), PO Box 790, Wellington, New Zealand (URL: http://www.eqc.govt.nz/).