White Island was visited on 16 February, and was viewed from the air on 23 February, 27 February, 2, and 16 March. Gas and a little ash were emitted at high pressure from a new vent in Christmas Crater on 16 February. . . . On 20 February between 1500 and 1800, observers about 55 km from the volcano noted a black ash column rising to about 1500 m, the largest seen since November 1977. During this activity, vigorous tremor and trains of apparent B-type earthquakes were recorded. Tremor intensified 21-22 February, accompanied by large-amplitude long-duration earthquakes.

During the 23 February overflight, a moderate amount of gray ash rose to about 1200 m altitude from the new Christmas Crater vent. Strong fumarolic activity continued from various vents. Ash emission from Christmas Crater was continuing on 27 February, and had begun from Gilliver (the November 1966-March 1967 eruption crater), about 200 m to the NW, which previously had only fumarolic activity during the current eruption.

Between 27 February and 2 March, the seismograph recorded periods (45 minutes to 6 hours) of semi-continuous 3-4 Hz vibration and several low-frequency, probable B-type shocks. Gray ash covered White Island on 2 March, but no impact craters were seen near the Christmas Crater vents, which emitted a moderate amount of dark brown ash that rose to about 900 m altitude at low velocity. Some ash was in the steam column from Gilliver Crater, but less than on 27 February. Strong fumarolic activity continued at other vents.

Semi-continuous 3-5 Hz vibration was recorded 2-10 March accompanied by numerous A-type and some B-type shocks. After the l0th, seismic activity was limited to a few 45-80-minute trains of A-type events recorded 13-16 March.

A thick blanket of light gray ash covered all of White Island on 16 March. A 350 m-diameter collapse crater had formed since the 2 March overflight, bounded by concentric cracks that developed in the spring of 1977. The collapse crater occupied the area of the new Christmas Crater vent and older craters Gilliver, Sulphur, and Big John. Strong steaming obscured the crater floor, but it appeared to have a maximum depth of about 100 m. Episodic emission of ash and blocks (to a maximum height of about 200 m) was occurring from the collapse crater, at the approximate former location of Sulphur Crater.

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.

Information Contacts: I. Nairn and B. Scott, NZGS, Rotorua.