Feb 15 2007 - White Island Activity

The temperature of White Island's Crater Lake has now reached 74 ºC, the highest ever recorded. Over the last 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. A recent 6 m drop in water level may cause instability in the geothermal system that could result in minor eruptive activity at the island, said Brad Scott, GNS Science Volcano Surveillance Co-ordinator.

In August 2006 the lake temperature was 48 - 50 ºC, by January 2007 it was over 60 ºC, and has now risen to 74 ºC. The crater lake waters are also very acidic. "The result is like scalding hot battery acid", said Brad Scott, commenting after a visit to the offshore volcano on Tuesday.

The drop in water level corresponds to a decrease in the volume of the 400 m diameter lake of 10%. Water seeping from then lake onto the surrounding crater floor has now stopped resulting in some prominent hot pools and streams drying up.

Gas being released into the atmosphere above the island has also increased. Sulphur dioxide flux has risen from 300 to around 500 tonnes/day over the last eight months and carbon dioxide from around 1,000 to 1,400 tonnes/day. Brad Scott said that "The increase in gas through the lake might cause some discomfort to visitors to the island when they are close to the lake".

A minor increase in seismic activity has accompanied the changes in the lake, but no significant ground deformation has been detected by surveys.