A slower-than-expected increase in lake temperature suggests a partial blockage may exist in the vent beneath the lake, preventing the hot gas from entering the lake, that’s the latest from GNS following last week’s increase in Ruapehu’s Volcanic Alert Level.
The potential blockage could allow pressure to build up within the volcano. GNS confirmed that Mt Ruapehu’s Crater Lake (Te Wai ā-moe) is continuing to rise in temperature, albeit slowly.
Two weeks ago, Mt Ruapehu’s Crater Lake entered a new heating cycle.
Duty Volcanologist, Geoff Kilgour said “Strong tremor has continued throughout this heating period”
“Over the past week, the lake has heated further to ~32 °C (from 31°C last week). The slow heating has been hindered by heavy rainfall at the volcano and [the] influx of cold water into the lake. The strong tremor reported last week continues”
“The interpretation of this activity is consistent with elevated volcanic unrest and therefore the Volcanic Alert Level remains at Level 2”
Kilgour announced that GNS has raised the Mt Ruapehu aviation colour code to Yellow. This indicates to aircraft operators that they need to take flight activity at Ruapehu into greater account.
At Volcanic Alert Level 2, eruptions are usually more likely than at Volcanic Alert Level 1, however, the Volcanic Alert Level should not be used to forecast future activity.
Last week Ruapehu District Mayor, Don Cameron said he’s got his eye on the mountain. Speaking to RNZ Cameron said, “Don’t worry, I’m checking to make sure there’s no smoke coming out of the crater because we’re right underneath it.”
GNS Science and the National Geohazards Monitoring Centre continue to closely monitor the Ruapehu for any further changes.
The closure of 2km around the crater lake put in place by the Department of Conservation remains in effect while Mt Tongariro, the Tongariro Alpine Crossing, and Tongariro Northern Circuit are not affected.
All DOC tracks and huts in Tongariro National Park remain open.