On 19 December GeoNet reported that activity at Whakaari/White Island remained low based on gas and observation flights conducted over the previous two months. Minor steam-and-gas emissions rose from a cluster of fumarolic vents located on the W shore of the lake; there has been no evidence of ash in the emissions. The discharge rates of the emissions during the year were characterized by low-to-moderate levels which were typical. Temperatures at the larger vents generally declined. The level of the lake had dropped, isolating a small pool from the main body of the lake. 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). GeoNet noted that Alert Levels reflect the level of unrest at the volcano but also consider the greater level of uncertainty due to the current lack of consistent and useful real-time data.

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