The first eruption of Mount Tongariro in a century was preceded by a lift in the alert level yesterday of New Zealand’s largest volcano - White Island in the Bay of Plenty.
White Island’s alert level was raised to Level 2 at 6.30pm last night – about six hours before the eruption on Mt Tongariro’s Te Mari crater.
A smoking White Island from Looking Glass Gardens in Te Puke. Photo: Jessica Brockett.
GNS Science raised the alert level after the White Island web camera captured a small eruption at about 4.55am on Sunday from the Crater Lake. During the past week there has been an increase in volcanic tremors and volcanic gas levels.
The Volcanic Alert Level is now raised to Level 2 – meaning the onset of eruptive activity, accompanied by changes to monitored indicators and minor eruptive activity.
The Aviation Colour Code is changed to Orange.
This is confirmation that small scale eruptions are now occurring on the island and GNS confirms the risk to visitors has increased.
White Island, about 48km off the Bay of Plenty coast, is an active volcano and there is always risk when visiting the island and vessels travelling nearby should keep alert.
Between Friday, July 27 and Saturday, July 28 the lake level in the Crater Lake at White Island rose by about 3m to 5m.
A volcanic earthquake was also recorded indicating an eruption may have occurred. A flow of gas and steam has been present through the lake and from vents near the lake since then.
A gas flight on August 1 recorded increases of sulphur gases in the steam and volcanic gas plume.
Activity at the island has been increasing since early July with intermittent periods of volcanic tremors, becoming more continuous since July 28. A particularly stronger episode was recorded overnight August 4-5, and ended in a volcanic earthquake at 4.54am.
Examination of the images from the Factory webcam between 4.54am and 4.57am on August 4 revealed an eruption from the Crater Lake.
Meanwhile there have been no further reports of activity from Mt Tongariro which erupted at 11.50pm last night.
The eruption was at the Te Mari crater on the volcano’s north western flank. The crate is the site of the last eruptions in 1869, 1892, 1896 and 1897.
The upper Te Mari Crater was formed during an explosive eruption in 1869. MÄori descriptions talk of "bright red flame through the smoke that would burst and fall like snow".
In November 1892 Te MÄri again belched forth an immense quantity of steam, mud and boulders; the ejected material rose 2000 - 3000 feet (600- 900 m) before rushing down the mountain side. The last eruption began in November 1896 and activity lasted until October 1897.
There is a media briefing on the Tongariro activity at Taupo at 10am.
The volcanic threat level activity scale:
0 Typical background surface activity; seismicity, deformation and heat flow at low levels. Usual dormant or quiescent state.
1 Departure from typical background surface activity. Signs of volcano unrest.
2 Onset of eruptive activity, accompanied by changes to monitored indicators. Minor eruptive activity.
3 Increased vigour of ongoing activity and monitored indicators. Significant effects on volcano, possible effects beyond. Significant local eruption in progress.
4 Significant change to ongoing activity and monitored indicators. Effects beyond volcano. Hazardous local eruption in progress.
5 Hazardous large volcanic eruption in progress. Large hazardous eruption in progress.