On 18 January GeoNet reported results from an overflight of Whakaari/White Island the week before, noting a significant decrease of temperatures at the active vent area and a small decrease in gas emissions. Temperatures in the main vent area were as high as 191 degrees Celsius, a decrease from a high value of 516 measured in December. Gas emissions had slightly decreased since December; both sulfur dioxide and carbon dioxide gas emission rates were slightly below the 10-year average. Both the gas-emission and temperature data were consistent with a degassing magma body below the surface. Very minor ash emissions continued to be visible with deposits only extending around the active vents. The water in the lake had receded likely due to recent dry weather conditions. 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