NZGS personnel flew over White Island on 13 June. A vapor cloud produced by several fumarolic areas rose to a maximum height of about 1 km. A thin layer of gray ash mantled the main crater floor, obliterating footprints left by the 26 May survey party. A band of grey ash trending NE from 1978 Crater was particularly conspicuous on the outer slopes of White Island. Impact craters, numerous on the E side of 1978 Crater, extended several hundred meters to the ESE, farther than at any time during 1980. The distant impact craters appeared large (no size estimate given) but were widely spaced. Seismicity during the few days prior to the overflight was characterized by periods of moderate-amplitude, high-frequency tremor interspersed with longer periods when tremor was low in both amplitude and frequency or was entirely absent. Brief episodes of high-amplitude, high-frequency tremor were recorded on 11 June (4 minutes) and 13 June (1.5 minutes). Two A-type shocks occurred about 2.5 minutes apart on 13 June, about 3 hours before the 1.5-minute episode of intense tremor. None of the strong seismicity occurred during the overflight.

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: B. Houghton, E. Lloyd, and I. Nairn, NZGS, Rotorua.