On 7 September GeoNet reported that access to continuous data streams from the last operating earthquake and pressure sensor on Whakaari/White Island had recently been lost, hindering scientists’ ability to distinguish between various levels of unrest. The Volcanic Alert Level was raised to 2 and the Aviation Color Code was changed to Yellow not because of actual increased activity but to reflect uncertainty in the interpretation of events on the island. Observations and gas-monitoring flights will be conducted more frequently until the island can visited to service the equipment and power supplies. Images from island webcams continued to be intermittently available. The report noted that low levels of activity on the island were observed during the last overflight on 31 August. Tall steam-and-gas plumes are sometimes observed from the mainland coast.

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