Two brief periods of volcanic tremor, each followed by multiple earthquakes, were recorded during June. After low-frequency tremor between 0100 and 2000 on 8 June, multiple shocks occurred at 002645 on the 9th. Medium-frequency tremor lasting from 1200 on 22 June until 1100 on 24 June was succeeded by a high-frequency tremor episode beginning at 1518 on the 24th and culminating in a series of earthquakes at about 1646. Local seismicity was otherwise limited to a few small earthquakes per day.

White Island was inspected from the air on 28 June. No evidence of major eruptive activity since 17 May was observed. Voluminous steam emission from the new collapse crater (Gibrus) produced a convoluting steam column that rose about 600 m. Some new fumaroles were visible inside Gibrus, but other fumarolic activity had declined. A formerly hot (>550°C in late March) and vigorous fumarole NW of Noisy Nellie had declined to weak steaming. Two new pits were observed within Christmas Crater. The larger, 20-25 m in diameter, contained a pond of green water; the smaller, 15 m in diameter, was surrounded by a small amount of grayish ejecta.

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: P. van der Werff, I. Nairn, and B. Scott, NZGS, Rotorua.