Aug 22 2005, 2:00 pm - Ruapehu Volcano

Recent Crater Lake visits have recorded a rise in the temperature of the lake. On 4 August the temperature was 23.3°C, and on 21 August it had risen to 32.3°C. The previous heating cycle peaked in February 2005 at 39°C.

Volcanic tremor recommenced at Ruapehu during July, and continues at varying levels. Volcanic tremor is not unusual at Ruapehu; however this is the strongest tremor recorded since November 2004.

Ruapehu Crater Lake will often warm following periods of volcanic tremor, and the present observations are following that trend. Heating cycles are common at Ruapehu, with the temperature ranging from about 15°C to 40°C, occurring every 9 - 12 months and lasting 1 - 3 months.
As the lake warms, steam plumes may be observed under favourable conditions (cool, calm days).

The Alert Level for Ruapehu remains at Alert Level 1, as there is no change in activity.

Brad Scott
Volcano Surveillance Co-ordinator