Oct 23 2008, 12:00 pm - White Island Volcano

The Crater Lake at White Island continues to refill. The lake, which almost completely evaporated in late-October 2007, started to refill in December 2007 and has now risen about 15 metres to be within about 9 metres of overflow. This rise in lake level has started to affect the geothermal features on the Main Crater floor.

Many new springs are forming on the Main Crater floor, and older springs are starting to flow again. These changes are similar to those observed during the previous lake filling (2004 - 2006). The Crater Lake temperature remains hot at 57 °C and the lake colour has also changed to a light green, reflecting little suspended sediment.

On the south side of the Main Crater floor, about half way between the lake and the sea, is an area of high temperature (101 - 103 °C) fumaroles. Steam, gas and mud emissions creating acid rain have increased from the largest vent in the last couple of weeks, and this will continue as the lake rises. Fumarole activity in this area has been increasing for several years. Activity has fluctuated in these features and they have varied between being ‘wet’ and ‘dry’ dependent on the water level in the Crater Lake.

Other monitoring, including the deformation surveys and soil gas mapping, have also shown changes about this fumarole area as it has heated and increased in activity. The current changes represent changes in the shallow geothermal system related to the rising water levels on the island.

White Island’s Crater Lake occupies a crater that formed during eruptions in the 1970s – 1990s. The last eruption at White Island, in 2000, occurred from a vent that is now beneath the lake.

No other significant changes have been observed at White Island.

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

Steven Sherburn
Duty Volcanologist