Unrest reported at Taupō Volcano, new equipment installed

Unrest at Taupō Volcano continues.

GeoNet has reported continued unrest at Taupō Volcano this morning, with small earthquakes and land movement above background levels.

It said in a bulletin the minor volcanic unrest began in May 2022, and the Volcanic Alert Level remains at 1 (minor volcanic unrest).

However, it also said the aftershock sequence following the magnitude 5.7 earthquake on November 30 last year has finished.

The magnitude 5.7 quake generated a small tsunami within Lake Taupō, caused about 175 millimetres of horizontal ground movement and about 180mm of vertical ground movement at Horomatangi, and was followed by a month of aftershocks, with 758 recorded by December 31.

Just under half of the earthquakes during the 2022/2023 unrest episode were linked with November’s main shock-aftershock sequence.

The current rate of earthquakes occurring per week was similar to other times during this period of unrest, indicating that minor unrest continues.

GeoNet duty volcanologist Ery Hughes wrote the update, and said ground deformation (land movement) continues around Lake Taupō, which Geonet measured using GNSS (GPS) instruments and lake levelling surveys. The Horomatangi Reef site continues to move after the earthquake towards the south-east.

GeoNet had partnered with the Tūwharetoa Māori Trust Board, Taupō District Council, and landowners to improve monitoring of the volcano by installing new equipment.

Two new seismometers were allowing it to more accurately locate earthquakes, while two new instruments to measure ground movements were helping it better understand the processes driving the long-term deformation at Taupō Volcano.

It also installed a near-real-time tsunami gauge to allow faster identification of the cause of potential future waves and tsunami.

This 2022/2023 unrest period at Taupō Volcano was the most recent of 18 historic unrest episodes in the past 150 years, none of which have ended in an eruption.

The unrest is caused by processes associated with magma and magma-related hot water, gas, and steam deep under the volcano generating earthquakes and ground movement. GNS Science continues to actively monitor the volcano.

Hughes said the Volcanic Alert Level reflects the current level of volcanic unrest or activity and is not a forecast of future activity.

“While Volcanic Alert Level 1 is mostly associated with environmental hazards, potential for eruption hazards also exists.”

Further information about the Volcanic Alert Levels and what they mean can be found here.

More information about caldera unrest can be accessed from this report.