S. Harvey reported that continuous ash eruptions were visible from Whakatane beginning 9 April. The ash clouds were voluminous, but did not rise to great heights. During the first 2 days of the activity, the clouds were pinkish brown and were accompanied by emission of white vapor from a vent to the E. On 11 April, the ash clouds were black and vapor emission had apparently ceased.

At 1114 on 12 April, the White Island seismograph recorded a large-amplitude, high-frequency event with virtually instantaneous onset, against a background of the almost continuous high-frequency tremor that has characterized long periods of the seismic record in recent months. At about the same time, persons on the mainland saw a large ash eruption.

NZGS personnel flew over the volcano about 2 hours later. Red-brown ash rose from deep within 1978 Crater to about 700 m height. Impact craters were seen inside 1978 Crater and blocks littered the ground within 20 m of the SE rim. Much of the main crater floor was mantled by ash, including the area where the blocks were deposited. However, there was no ash on the blocks, which were therefore assumed to have been ejected quite recently, probably by the late-morning explosion. The interior of 1978 Crater has changed little since the present active vent was established in late 1978.

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: E. Lloyd, NZGS, Rotorua.