Mount Ruapehu's alert level drops to 1, volcanic activity declines

The alert level change on Mount Ruapehu was announced by GNS Science today. Photo / File

A decrease in activity on Mount Ruapehu has seen its alert level dropped to one.

The change was announced by GNS Science today as volcanic gas emissions return to normal levels and volcanic tremors slow.

"While the crater lake temperature remains high, the period of moderate to heightened volcanic unrest has now ended," duty volcanologist Steven Sherburn said.

On December 30, volcanic gas emissions from Ruapehu had declined to normal levels, from the highs observed in mid-December.

On December 29, volcanic tremor, which had previously been slightly elevated following
a volcanic earthquake on December 26, declined to a low level and had remained low.

The temperature of water in Crater Lake reached a maximum of 43C on December 21 but in the last three weeks has declined to 40C.

The Volcanic Alert Level was lowered to Level one as it reflected the current level of
volcanic activity.

Mount Ruapehu was an active volcano and had the potential to erupt with little or no warning when in a state of volcanic unrest, Sherburn said.

The Volcanic Alert Level should not be used to forecast future activity, however at
Volcanic Alert Level 1, eruptions are less likely.

GNS Science and the National Geohazards Monitoring Centre continue to closely
monitor Mount Ruapehu for further changes.