Small set of quakes underneath Mt Ruapehu summit area

A small set of earthquakes struck underneath Mt Ruapehu at the weekend. Photo / File

A series of small volcanic earthquakes rumbled beneath Mt Ruapehu at the weekend.

GNS Science says the larger events at the start of the quakes were approximately magnitude 1.5 and with later, smaller events were too small to be located by its earthquake detection-location system.

"The seismic recordings indicate a source beneath the summit area, which is normal for
volcanic earthquakes and volcanic tremor at Ruapehu," a GNS spokesman said.

"The sequence now appears to be over."

The Volcanic Alert Level remains at 1, reflecting the current level of volcanic activity, the spokesman said. The Aviation Colour Code remains Green.

"It is not unusual to observe volcanic earthquakes on Ruapehu and other episodes of
increased seismic activity were observed during March 2018, April 2016 and September
2017.

"None of these resulted in a sustained increase in volcanic unrest."

Mt Ruapehu is monitored through a network of seismic and acoustic sensors, GPS receivers, sensors in the lake and visits to the lake area by GeoNet staff.

"These include gas flights over Ruapehu for measuring gas emission and a monitoring visit to Te Wai ā-moe (the Crater Lake) to collect water and gas samples as weather allows."

Te Wai ā-moe's temperature has been around 24-25C for the last few months, the spokesman said.

Mt Ruapehu was being closely monitored for continued signs of activity by GNS Science and the National Geohazards Monitoring Centre.