The crater lake, which started to form in the active crater at White Island in August 2003, is now only 1m below overflow level. Seepage is occurring from the lake onto the floor of the Main Crater and the barrier holding back the lake is eroding.

In October 2004, the lake rose to within 3.9m of overflow before rapidly dropping 1.7m (possibly due to an underground leak), stabilising at 5.5m below overflow. The lake level has since resumed rising, and is now only 1m below overflow (see plot below). The lake is expected to continue rising until overflow occurs.

The lake is currently contained by a barrier of softer material on the north-east side. This barrier has eroded back 9 - 13 metres since November 2004 and is now only 10.5m wide. It is expected to erode further as the water level rises. Seepage from the lake has increased the flow of water in the streams that drain the Main Crater floor. Much of this area has become waterlogged and access is difficult and dangerous.

If the lake continues to rise at the current rate it is expected to overflow before the barrier erodes away. The overflow could occur as soon as the next 6 - 8 weeks, but will be dependent on factors like rainfall, volcanic fluid input, temperature and leakage. Once the lake starts to overflow the amount of water in the streams will increase significantly. This is the largest lake to have formed within the active crater and has drowned the formerly active vents.

Alert Status

The Volcanic Alert Level for White Island remains at Level 1

Brad Scott
Volcano Surveillance Co-ordinator