GNS Science volcanologists report that the lava dome on White Island has not changed in the last 10 days.
On 10 December they had noticed a spiny lava dome at White Island in a small crater formed as a result of eruptions in August. Yesterday they visited again and confirmed there was no sign of it growing.
"On Wednesday we were able to get a really clear view of the spiny lava dome. By comparing the photos we took with previous ones we are reasonably sure that it is not growing, and there have been no major changes to its surface", said GNS Science volcanologist Steve Sherburn.
They also used an Infra-Red thermometer to measure temperatures of the dome and the surrounding water. Several small lakes now occupy parts of where a large lake was before August. "The highest I got from the dome was 187 C while the hot lake to the south was at least 71 C and upwelling strongly, whereas the cool lake on the north side of the dome was only 35 C" reported GNS Science volcanologist Brad Scott.
Comments from tour operators at White Island suggest the dome has been visible for about a month. How long the dome has been growing is unknown, but possibly since the ash eruption in early August.
Lava domes are usually formed by magma that has lost most of its gases so that it is very sticky. This causes the magma to pile up over the volcanic event and form a dome. Lava domes are common at some volcanoes, but have never been seen before at White Island. Magma last reached the surface at White Island in 2000. At that time it was erupted explosively as molten rocks called volcanic bombs, rather than forming a dome.
The Volcanic Alert Level remains at 2 (minor eruptive activity) and the Aviation Colour Code remains at Orange.