GNS Science says small volcanic earthquakes can be expected a Mt Ruapehu as the Crater Lake goes through a new heating phase.
Crater Lake with Crater Basin Glacier behind, Mt Ruapehu. Photo: Shaun Eaves / VUW
The alert level is at 1 - with the main risks steam discharge, volcanic gas, earthquakes, landslides and hydrothermal activity, although eruptions could still occur.
GNS Science volcanologist Craig Miller says during heating phases small volcanic earthquakes are common, caused by an influx of hot steam into the lake.
He said current readings indicate the lake was following a normal heating pattern.
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"From early July to early September 2021, the lake temperature rose from 20C to 39C. Through to mid-October the lake temperature declined to around 23-25C. Since early December a heating trend has become established, and the lake temperature is now 31C."
"The results from our continuous monitoring of seismic activity, lake temperature and water level indicate that key monitoring parameters remain within normal ranges," Miller said.
GNS Science and the National Geohazards Monitoring Centre will continue to closely monitor Mt Ruapehu for further changes," he added.
The Aviation Colour Code is unaffected by the current heating phase and remains at colour Green.