Muddy, geyser-like explosions in active crater at Whakaari/White Island

Thursday, 26 September 2019

Muddy, geyser-like explosions up to 10 metres high have started shooting out of the active crater lake at Whakaari/White Island, but GeoNet says it's not a sign of increasing volcanic activity.

Rather, the level of the crater lake has been rising since early August, so hot steam and gas coming out of an active vent area are now having to pass through water.

'Geysering-type activity has become established in the main active vent due to hot steam and gas passing through the now drowned active vent area,' GNS Science duty volcanologist Steve Sherburn said.

'This geysering activity is not a sign of increasing volcanic activity. Normally the gas and steam would vent directly to the atmosphere, now it's through the water in the vents and is visible as the geyser-like activity.

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The small scale geyser-like explosions of mud and steam have been seen in the active vent area for the past three weeks, and did not pose a hazard to visitors to the island, Sherburn said.

Recent measurements made on the island and continuous data showed no change in monitored parameters outside the expected signals for minor volcanic unrest.

That meant the volcanic alert level remained at level 1 - indicating minor volcanic unrest - and  the aviation colour code remained green - meaning the volcano remains in a non-eruptive state.