Report on Whakaari/White Island (New Zealand) — 23 January-29 January 2013
Smithsonian / US Geological Survey Weekly Volcanic Activity Report,
23 January-29 January 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, 23 January-29 January 2013. Smithsonian Institution and US Geological Survey.
37.52°S, 177.18°E; summit elev. 294 m
All times are local (unless otherwise noted)
At 1600 on 24 January the GeoNet Data Centre reported that seismicity at White Island had changed during the previous 20-30 hours; volcanic tremor decreased while hybrid earthquakes appeared, which suggested magma movement within the volcano. The Aviation Colour Code was raised to Orange (second highest on a four-color scale) and the Volcanic Alert Level remained at 1 (on a scale of 0-5).
On 25 January scientists conducted an overflight to measure gas emissions and found that the levels were similar to those measured on 19 December 2012. The scientists observed vigorous mud geysering in the crater lake. Seismicity remained above background levels.
On 29 January continuous tremor that had been recorded during the past few weeks changed to intermittent tremor, which remained strong. The crater lake was drying out and frequent bursts of mud, steam, and gas were still vigorous; mud and rock were ejected tens of meters out of the lake area. Steam-and-gas plumes that rose from the crater were visible from the Bay of Plenty coastline. GNS Science's past monitoring of the island showed that weak ash eruptions had often followed drying out of the same type of mud-filled lake.
Geological Summary. 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.