May 17 2005, 3:00 pm - White Island Volcano

Comparison photos of lake levels since November 2004.

The crater lake, which started to form in the active crater at White Island in August 2003, is now only 3.3 m from overflow level. Considerable seepage is occurring from the lake onto the Main Crater floor and the barrier holding back the lake is eroding.

In October 2004 the lake rose to within 3.9 m of overflow, before rapidly dropping 1.7 m, (possibly due to an underground leak) stabilising at 5.5 m below overflow. The lake level has since resumed rising, and in early May reached 3.3 m below overflow (see plot below). The lake is expected to continue rising through winter with continued rainfall.

The lake is currently being held in by a barrier of softer material on the northeast side. This barrier has eroded back 7 - 8 metres since November 2004 and is now only 15 m 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.

This is the largest lake to have formed within the active crater and has drowned the formerly active vents. Future eruptions will occur through the crater lake ejecting moderate volumes of water that may flood down the Main Crater floor towards the sea. This is a significant change in the nature of volcanic hazards on the island.

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

Brad Scott
Volcano Surveillance Co-ordinator