Volcanic unrest remains at alert level one at Lake Taupō as earthquakes and ground deformation continue.
It comes after GeoNet upgraded Taupō volcano's alert level from zero to one for the first time ever, following about 750 earthquakes since May.
The depth of the quakes is from four to 13km beneath the lake since unrest at Taupō began in May.
In the latest update provided by GeoNet, quakes seen in the last week have mainly struck in the eastern part of Lake Taupō. A graph shows the number of quakes detected and located has climbed since early this year.
Since May, GeoNet has observed land movement or uplift at a rate of 60 ± 20mm per year at a site on Horomatangi Reef in Lake Taupō.
"We interpret the ground uplift and earthquake activity to be caused by the movement of magma and the hydrothermal fluids inside the volcano," GeoNet said.
Their experts believe activity could continue at the lake for the coming weeks or even months at different rates or intensities.
And while some of the quakes can be felt by those close to Lake Taupō, GeoNet said ground deformation is only detected by their monitoring instruments.
What does volcanic unrest mean? GeoNet breaks it down
Volcanic unrest is when magma or magma-heated hot water and steam force their way through the ground beneath a volcano, producing earthquakes, ground movement and changes in hydrothermal systems.
There have been 17 previous episodes of unrest at Taupō over the past 150 years.
Several of these were more severe than what we are currently observing at Taupō. None of these episodes, or the many other episodes which would have occurred over the past 1800 years before written records were kept, ended in an eruption.
The last eruption at Taupō volcano was in 232 AD ± 10 years. The chance of an eruption at Taupō remains very low in any one year.
Episodes of unrest are common at calderas around the world. Volcanic unrest at volcanoes like Taupō could continue for months or years and not result in an eruption.
If there was increased unrest which is not observed to date, then we would see more substantial impacts on the local area. These could include earthquakes with the ground shaking and potentially landslides on steep cliffs, especially after rain.
Liquefaction can occur in the event of larger earthquakes. Substantially higher levels of ground deformation, tens of centimetres or metres, would only occur at higher unrest levels and could have impacts such as damaging underground services.
Changes in geothermal activity may also occur with stronger, evolving unrest. This could be beneath the lake or at established geothermal areas in the Taupō area.
GeoNet said the current alert level reflects the unrest and isn't a forecast for future volcanic activity.
"While Volcano Alert Level 1 is mostly associated with environmental hazards, the potential for eruption hazards also exists."
