Report on Whakaari/White Island (New Zealand) — 28 April-4 May 2021
Smithsonian / US Geological Survey Weekly Volcanic Activity Report,
28 April-4 May 2021
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2021. Report on Whakaari/White Island (New Zealand). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 28 April-4 May 2021. Smithsonian Institution and US Geological Survey.
37.52°S, 177.18°E; summit elev. 294 m
All times are local (unless otherwise noted)
GeoNet reported that a brief period of low-energy tremor and acoustic signals was recorded at Whakaari/White Island beginning at 2230 on 29 April. During an overflight on 30 April scientists did not observe new deposits near the active vent or thermal anomalies at the active vent area. Gas-emission rates had been relatively unchanged since March. The brief period of increased activity was likely caused by a series of low-energy subterranean explosions, similar to activity observed in mid-February and early-mid March. Seismic tremor remained at background levels. The Volcanic Alert Level remained at 1 and the Aviation Color Code remained at Green.
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.