Report on White Island (New Zealand) — 30 January-5 February 2013
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 30 January-5 February 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, 30 January-5 February 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 30 January GeoNet Data Centre reported that White Island's "hot lake" had dried up and a small tuff cone was forming on the former floor of the lake. The active vent continued to eject bursts of mud, rock, steam, and gas 50-100 m high. This activity along with the seismic activity was intermittent. Gas measurements taken during an overflight showed that the levels of volcanic gases emitted from the volcano were slightly higher than the levels measured the previous week: carbon dioxide gas flux increased from 1,800 to 2,000 tons/day, sulfur dioxide flux increased from 366 to 600 tons/day, and hydrogen sulfide flux was 19 tons/day (previously 15 tons/day). During 30-31 January seismicity changed to continuous tremor and remained at a high level. The Aviation Colour Code remained at Orange (second highest on a four-color scale) and the Volcanic 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.