GeoNet reported that minor eruptive activity at Whakaari/White Island during 21-27 August was characterized by elevated sulfur dioxide gas emissions and minor ash emissions. During a 21 August overflight, scientists observed gas, steam, and ash plumes rising 600-900 m from the new vent that had opened in early August. Ashfall on the island was seen within a 1 km radius of the vent. The temperature at the vent was about 590 degrees Celsius based on infrared images taken during the overflight. Low-level plumes containing minor amounts of ash were identified in satellite images and images from webcams located in Whakatane and Te Kaha during the week. In calm weather conditions the plumes were sometimes visible rising as high as 2 km a.s.l., and at other times drifted tens of kilometers downwind. During 22-23 August the plumes drifted towards the Bay of Plenty. According to a news report at least 10 flights in and out of both Tauranga and Rotorua Airports were cancelled and three were delayed during the morning on 22 August. The flight disruptions were a “proactive safety measure” and by 1130 airport operations were back to normal. The Volcanic Alert Level remained at 3 (on a scale of 0-5) and the Aviation Color Code remained at Orange (the second highest level on a four-color scale).

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.

Sources: GeoNet, Radio New Zealand