May 3 2007, 10:00 am - White Island Volcano

The rapid decrease in the level of the Crater Lake seen over the last few months at White Island has continued. Recent observations have confirmed the lake is now over 28 metres below overflow level and the depth of water in the lake is now likely to be about 10 metres. The lake level was about 9 metres below overflow in early March. The fall in lake level has been very rapid during April. Both the area and volume of the lake have significantly decreased. The temperature of the lake has also declined, from 74 to 64ºC, probably due to less input from high temperature steam vents, which are now above the lake.

As the water level has fallen many steam vents and fumaroles have been exposed, and under suitable weather conditions these can combine to produce transient steam plumes that rise above the island. Recently some have reached as high as 3 km (10,000 feet), and have been reported as eruptions. No eruptions have occurred.

No changes in any of the monitoring data would indicate an increase in volcanic activity in the near future. However, the water level fall will change the pressures in the geothermal system and this may become unstable and could result in local steam explosions.

The Alert Level for White Island remains at Alert Level 1; there is no significant change in volcanic activity on the island.

Brad Scott
Volcano Surveillance Co-ordinator