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Geologists say the crater lake on White Island has jumped to a record temperature of 74degC and the water level has plunged 6m -- possibly signalling an eruption on the island.
The drop in water level "may cause instability in the geothermal system that could result in minor eruptive activity," said GNS Science volcanic surveillance co-ordinator Brad Scott.
White Island in the Bay of Plenty has not erupted since 2000 but the water level has risen 30m in the past six years.
The water temperature in its crater lake has jumped from 45degC last August to over 60degC in January and was now 74degC. The lake water was also very acidic "like scalding hot battery acid", Mr Scott said.
"Over the past few months, increased heat and gas flow into the volcano has caused both a rapid evaporation of the lake and more gas being released into the atmosphere."
The drop in water level is equivalent to a 10 per cent fall in the volume of the lake, and some prominent hot pools and streams on the island are drying up because water has stopped leaking out of the crater.
Sulphur dioxide gas being released into the atmosphere has jumped from 300 tonnes a day to 500 tonnes over the past eight months, and the amount of carbon dioxide being pumped out has risen from 1000 tonnes a day to 1400 tonnes.
"The increase in gas through the lake might cause some discomfort to visitors to the island when they are close to the lake," Mr Scott said.
- NZPA
