Report on White Island (New Zealand) — 24 April-30 April 2013
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 24 April-30 April 2013
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2013. Report on White Island (New Zealand). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 24 April-30 April 2013. Smithsonian Institution and US Geological Survey.
37.52°S, 177.18°E; summit elev. 321 m
All times are local (unless otherwise noted)
On 29 April GeoNet Data Centre reported that activity at White Island remained at a persistently low level, characterized by tremor and degassing. No mud or ash eruptions had been observed since early April. A volcanologist visited the island the previous week and observed that increased rainfall had caused the two lakes to merge together into one larger lake. The temperature of the lake was 62 degrees Celsius and the lava-dome temperature was 200 degrees. The lower level of activity prompted GeoNet to reduce the Aviation Colour Code to Green (indicating no active eruption). The Volcano Alert Level remained at 1 (on a scale of 0-5).
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.