Tongariro, White Island alerts downgraded

Steam billows from vents at the summit of Mt Tongariro. Photo / Alan Gibson

Volcanic alert levels at Mt Tongariro and White Island have been downgraded.

Tongariro erupted late on August 6, throwing out rock, ash and steam. It was the first time since 1897 that it had erupted.

Volcanologist Steven Sherburn from GNS Science said minor amounts of ash were emitted from the volcano during the first few days after the eruption, but there had been no new activity recently.

"Seismic activity, which had been above normal for some of the period preceding the eruption, returned to normal low levels after the eruption."

Mr Sherburn said the alert level had been reduced from level 2 [minor eruptive activity] to level 1 [signs of volcano unrest]. The aviation colour code, which applies to aircraft flying near Tongariro, remains at yellow.

Mr Sherburn said GNS would continue to monitor the volcano.

The alert level for White Island in the Bay of Plenty has also been reduced, from level two to one, after recent "minor eruptive activity" stopped.

"Over the last week the amount of ash being erupted at White Island has gradually declined. Little or no ash has been visible in the plume this week," said Mr Sherburn

The risk to visitors to the island has reduced from last week but remains higher than normal and "explosive eruptions can still occur at any time with little or no warnin"', he said.

He advised people visiting the island to be cautious.