White Island is remaining at a persistent low level of activity during the last month.

GNS volcanologist Brad Scott says no small mud or ash eruptions have been observed since early April.

The enlarged lake at White Island.

The lower level of activity has prompted GeoNet to reduce the Aviation Colour Code to Green (indicating no active eruption activity) from Yellow (indicating heightened unrest and eruptive activity). The Volcano Alert Level remains at 1.

Brad says a seismic tremor has continued, within a range of low to moderate amplitude levels, while gas measurements continue to show a consistent magma degassing signature.

'The rainfall over the past few weeks has caused a lake level increase and the two lakes have joined, creating one larger lake.

'Temperature of the lake is variable, with a maximum of about 62 degrees being measured. In contrast, the nearby lava dome which was extruded in November has temperatures of about 200 degrees.”

As part of GeoNet's programme to improve monitoring at White Island the web camera on the crater rim has been upgraded, says Brad.

This provides clearer pictures and better low light (night) views. Camera images can be seen here at: http://www.geonet.org.nz/volcano/info/whiteisland

The camera technology uses two cameras: one is a standard daylight camera and the other a special low light camera.

The low light camera amplifies any ambient infrared source from various natural sources, allowing us to see better night images.

Brad says it is not imaging heat but it amplifies low levels of ambient light that contain energy, so they appear as glows in the images.
The camera isn't a thermal imaging camera.

GeoNet has the same technology installed at other volcanoes.