A swarm of 84 small earthquakes has softly shaken Lake Taupō over the past three weeks.
GeoNet has recorded 84 small quakes under the lake since April 28, at depths of 7-16 kilometres.
Only two have been over 3 on the Richter scale.
The earthquakes are in two groupings - one cluster in the middle of the lake and one along the eastern shore.
GeoNet said quake swarms were common in the area and several were recorded each year.
"Larger ones have lasted weeks to months and can include many hundreds of earthquakes."
There have more than 4200 tremors under Lake Taupō in the past 10 years.
The present swarm was in a similar place to a series in 2019, which was the subject of a study.
"That study showed the earthquakes are related to the margins of the hot mush zone under the volcano and are signs that Taupō volcano is active.
"Variations in the level of background unrest are common for caldera volcanoes like Taupō," GeoNet said.
RNZ