GeoNet reported that a vigorous volcanic plume at Whakaari/White Island was identified in satellite and webcam images on 9 August with the most active period occurring during 1300-1500. The plume drifted E and contained a minor amount of ash, prompting GeoNet to raise the Volcanic Alert Level to 3 (on a scale of 0-5) and the Aviation Color Code to Orange (the second highest level on a four-color scale). Activity diminished later that day.

Emissions with low ash content began around 0000 on 11 August that drifted W and were continuous at least through 1015. The ash plume rose to 1-2 km a.s.l. and a steam plume rose to around 2 km a.s.l. Sulfur dioxide emissions were identified in satellite data for the first time during the current active period, which began in May. The satellite instrument is less sensitive than instruments used during gas observations flights, suggesting that sulfur dioxide emissions had increased. Low-level plumes containing minor amounts of ash continued to be identified in satellite images and images from webcams located in Whakatane and Te Kaha during 12-14 August. Weather occasionally prevented visual observations. GeoNet noted that sulfur dioxide emissions coupled with minor eruptive activity suggested that magma had ascended to shallow levels.

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.

Source: GeoNet