Report on White Island (New Zealand) — July 1979
Scientific Event Alert Network Bulletin, vol. 4, no. 7 (July 1979)
Managing Editor: David Squires.
White Island (New Zealand) Explosion produces red ash
Please cite this report as:
Global Volcanism Program, 1979. Report on White Island (New Zealand). In: Squires, D. (ed.), Scientific Event Alert Network Bulletin, 4:7. Smithsonian Institution. https://doi.org/10.5479/si.GVP.SEAN197907-241040.
37.52°S, 177.18°E; summit elev. 321 m
All times are local (unless otherwise noted)
B. Adams reported a dark, pulsating tephra column that rose intermittently from White Island to about 1 km altitude. He first observed the eruption at about 0800 on 13 July from 50 km to the SSE. Ash appeared to be falling downwind from the vent. A white plume had been present over White Island for the previous several weeks.
NZGS personnel overflew the volcano on 16 July. An eruption cloud containing red ash emerged from the active vent in the SE section of 1978 crater, reaching about 600 m altitude before being blown N by a moderate wind. Much of White Island was covered by red ash, which was thick enough near the vent to cover the bombs ejected in April and May (04:5-6). No fresh impact craters were observed. Vigorous fumarolic activity continued at several sites within the main crater.
Geologic Background. Uninhabited 2 x 2.4 km White Island, one of New Zealand's most active volcanoes, is the 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 summit crater appears to be breached to the SE, because the shoreline corresponds to the level of several notches in the SE crater wall. Volckner Rocks, four sea stacks that are remnants of a lava dome, lie 5 km NNE. Intermittent moderate phreatomagmatic and strombolian eruptions have occurred throughout the short historical period beginning in 1826, but its activity also forms a prominent part of Maori legends. Formation of many new vents during the 19th and 20th centuries has produced 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.
Information Contacts: E. Lloyd, NZGS, Rotorua.