The temperature of the crater lake at Mt Ruapehu has dropped by two degrees, but the Volcanic Alert Level remains at two, with a large volcanic earthquake being recorded on Boxing Day.
The crater lake, Te Wai ā-moe, dropped to 41 degrees Celsius after a recording a maximum of 43 degrees on December 21, GNS Science said in a statement.
The organisation said the crater lake reaching temperatures between 40 and 46 degrees Celsius during heating-cooling cycles.
Volcanic tremors remain elevated with volcanic earthquakes also being recorded. The largest of these was a magnitude 2.2 quake under the volcano on Boxing Day
GNS Science said quakes of that size are uncommon, and, along with the elevated tremor and high lake temperature, are an indication of heightened volcanic unrest, meaning the alert level remains at two.
The Aviation Colour Code also remains at yellow.
“Mt Ruapehu is an active volcano and has the potential to erupt with little or no warning in a state of volcanic unrest,” GNSE Science’s statement read.
“The Volcanic Alert Level is still at Level 2 which reflects the current level of volcanic activity.”
GNS Science said they would continue to monitor Ruapehu closely and would attempt a gas flight to measure volcanic emissions.
They would also attempt to collect a sample from the crater lake to conduct further chemical analyses.