Report on Whakaari/White Island (New Zealand) — May 1993
Bulletin of the Global Volcanism Network, vol. 18, no. 5 (May 1993)
Managing Editor: Edward Venzke.
Whakaari/White Island (New Zealand) Ash emissions stop; steaming doesn't
Please cite this report as:
Global Volcanism Program, 1993. Report on Whakaari/White Island (New Zealand) (Venzke, E., ed.). Bulletin of the Global Volcanism Network, 18:5. Smithsonian Institution. https://doi.org/10.5479/si.GVP.BGVN199305-241040.
37.52°S, 177.18°E; summit elev. 294 m
All times are local (unless otherwise noted)
Weak ash emissions stopped in mid-February, although one explosion occurred near the end of the month. A crater lake was observed on the floor of Wade Crater near the end of March. Multiple visits were made by geologists from New Zealand and Japan to conduct microearthquake observations and make self potential measurements in the main crater.
Geologists noted no apparent changes on the crater floor during a 6 February visit, the first since 21 January. Conditions in the 1978/90 crater prevented observations. During a 16-17 February visit, observations were confined to the E end of main crater, where seismic recording equipment from the GSJ was installed, and from the NE rim. Light-brown, very fine ash emissions were rising ~150-200 m from unknown vents in the 1978/90 Crater Complex. Fallout from recent emissions had deposited ash between Donald Mound and Noisy Nellie (see figure 18), and farther N, filling all shallow erosion features in the area.
No ash emissions occurred during a visit to the rim of the 1978/90 Crater Complex at 1217 on 23 February. A deep, nearly continuous roaring noise was heard coming from deep in TV1 Crater, which was emitting steam. Recent landslide debris made up most of the floor of the 250-m-deep Wade Crater, though a small lake with geyser-type activity was present in the SW. A 50-80 m wide vent on the W side of the N crater wall was emitting gray fumes. There was no apparent activity in Royce or Princess craters. The N-facing wall of the flat area S of Princess Crater was severely cratered, with some of the impact craters producing small landslides. A lack of impact craters on the flat itself indicates a very directed blast, probably from the vent in Wade Crater. Increased steam emission was noted 25 February, originating from Wade, TV1, and possibly Princess craters. The steam column rose ~500 m before being blown to the E.
The rim of the 1978/90 Crater Complex was not visited on 2 March, when seismic monitoring equipment was installed and GPS observations were made, but no significant emissions were seen. A brief visit to the crater complex rim at 1237 on 9 March showed that activity was confined to Wade Crater, with no observable emissions from Royce, Princess, or TV1 craters. The only significant steam emissions were from vents on the E side of the collapsed wall in the May 91 Crater and deep in Wade Crater. Steam emission prevented a clear view of the floor of Wade Crater, but a lake was probably present.
A steam plume was rising ~500 m when geologists arrived on 15 March to retrieve the seismic equipment; emissions from the NE side appeared stronger. A visit to the rim of the crater complex at 1530 provided a clear view of the sub-craters. A gray-colored lake occupied the floor of Wade Crater, with conspicuous geysering and steaming in the SE. Waves from the SW suggested additional activity. The Royce Crater area had collapsed, filling any local vents. The most prolific steam emissions were coming from three fumaroles in the old SE wall of the May 91 Crater. Strong fumaroles were also present on the W wall of Wade Crater near the former May 91 Crater divide. Steam emissions were observed 16 March, but no one visited the crater rim.
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, S. Sherburn, and C. Wood, IGNS Wairakei; Y. Nishi and T. Tosha, GSJ, Japan.