Report on White Island (New Zealand) — 20 November-26 November 2019
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 20 November-26 November 2019
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2019. Report on White Island (New Zealand). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 20 November-26 November 2019. Smithsonian Institution and US Geological Survey.
37.52°S, 177.18°E; summit elev. 321 m
All times are local (unless otherwise noted)
GeoNet reported that gas emissions at White Island were at moderate-to-high levels during 18-25 November and tremor was at moderate levels. Gas-driven fountaining from active vents on the W side of the crater floor ejected mud a few meters in the air. The Volcanic Alert Level remained at 2 and the Aviation Color Code remained at Yellow.
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.