Report on Whakaari/White Island (New Zealand) — 3 July-9 July 2013
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 3 July-9 July 2013
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2013. Report on Whakaari/White Island (New Zealand). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 3 July-9 July 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 9 July GeoNet Data Centre reported that over the previous few weeks very small volcanic earthquakes occurred at White Island approximately every 70 seconds; the hundreds of small bursts created a unique daily pattern on the seismograph. The pattern of the volcanic earthquakes changed over time; the tremor bursts changed in size and frequency and sometimes merged into continuous tremor. Neither increased gas emissions nor changes in the hot lake and recently-erupted lava dome suggested that the process creating the earthquakes, possibly fluid moving through a crack, was occurring at depth. The Volcano Alert Level remained at 1 (on a scale of 0-5) and the Aviation Colour Code remained at Green (on a four-color scale).
Geologic Background. The uninhabited Whakaari/White Island 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 SE side of the crater is open at sea level, with the recent activity centered about 1 km from the shore close to the rear crater wall. Volckner Rocks, sea stacks that are remnants of a lava dome, lie 5 km NW. Descriptions of volcanism since 1826 have included intermittent moderate phreatic, phreatomagmatic, and Strombolian eruptions; activity there also forms a prominent part of Maori legends. The formation of many new vents during the 19th and 20th centuries caused 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. The official government name Whakaari/White Island is a combination of the full Maori name of Te Puia o Whakaari ("The Dramatic Volcano") and White Island (referencing the constant steam plume) given by Captain James Cook in 1769.