GeoNet reported that no further activity at Whakaari/White Island occurred after 25 May. Typical steam-and-gas emissions were visible on webcam images from the webcam located in Whakatane during 26-31 May when weather conditions allowed for observations. Vivid white steam-and-gas emissions from numerous vents were observed during a 31 May monitoring overflight. No clear signs of emitted ash were seen in webcam images or during the overflight, though GeoNet noted that low-level ash emissions could still have occurred. Gas data collected during the overflight showed elevated levels of magmatic gases compared to observations prior to the eruptions in May. Sulfur dioxide emissions were notably at some of the highest levels since measurements began at the island in 2003. Satellite data from 27 May showed no ground deformation. There are no sensors on the island; GeoNet relies on webcams and satellite imagery, complemented with occasional gas and observation flights. The Volcanic Alert Level remained at 2 (on a scale of 0-5) and the Aviation Color Code remained at Yellow (the second 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.

Source: GeoNet