Report on White Island (New Zealand) — 14 October-20 October 2015
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 14 October-20 October 2015
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2015. Report on White Island (New Zealand). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 14 October-20 October 2015. Smithsonian Institution and US Geological Survey.
37.52°S, 177.18°E; summit elev. 321 m
All times are local (unless otherwise noted)
On 14 October the GeoNet Data Centre reported a recent slight intensification of activity at White Island. Increased amounts of CO2 emitted from one of the large accessible fumaroles was detected on 1 October along with a temperature increase. SO2 emissions at the volcano also increased. On 8 October volcanic tremor magnitude strengthened and became banded (the signal disappeared and reappeared every few hours), commonly noted during eruptions and periods of unrest. The Volcanic Alert Level remained at 1 and the Aviation Colour Code remained Green.
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.