Report on White Island (New Zealand) — 31 July-6 August 2013
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 31 July-6 August 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, 31 July-6 August 2013. Smithsonian Institution and US Geological Survey.
37.52°S, 177.18°E; summit elev. 294 m
All times are local (unless otherwise noted)
On 5 August GeoNet Data Centre reported that minor activity at White Island had declined; the bursts of steam, gas, and mud observed the previous week were no longer visible in web cam images. The elevated volcanic tremor had decreased to near-background levels. The Volcano Alert Level remained at 1 (on a scale of 0-5) and the Aviation Colour Code was lowered to Green (on a four-color scale).
Geologic Background. The uninhabited White Island, also known as Whakaari in the Maori language, is the 2 x 2.4 km 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, sea stacks that are remnants of a lava dome, lie 5 km NW. Descriptions of eruptions since 1826 have included intermittent moderate phreatic, phreatomagmatic, and Strombolian eruptions; activity there 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. Explosive activity in December 2019 took place while tourists were present, resulting in many fatalities.