On 29 May GeoNet reported that activity at Whakaari/White Island continued in an elevated state of unrest. Gas and observations flights have resumed; sulfur dioxide and carbon dioxide gas flux increased from 20 to 27 May, possibly indicating a new body of magma at a shallow depth. Areas of lava remained hot on 20 May with temperatures around 500 degrees Celsius. Incandescence from gas emissions around the lobes was visible in nighttime webcam images. Tremor levels remained low overall, punctuated with occasional episodes of slightly elevated tremor. Some shallow-source volcanic earthquakes were recorded. Satellite-based measurements showed several centimeters of subsidence since the December 2019 eruption. The Volcanic Alert Level remained at 2 and the Aviation Color Code remained at Yellow.

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