Minor unrest ongoing at Taupō Volcano. Volcanic Alert Level remains at Level 1.
Minor volcanic unrest continues at Taupō Volcano, as shown by continued small earthquakes and ground deformation. The Volcanic Alert Level remains at 1 (minor volcanic unrest).
The earthquakes and deformation at Lake Taupō have continued since the last bulletin on 11 October 2022. The rate of earthquake activity has varied since the increase started in May. After a peak of about 30-40 events per week from June to September, the number of earthquakes dropped over the last month to about 10-12 per week. This has now risen again, over the last two weeks, to a little over 20 events per week. We have now located 840 earthquakes since the start of 2022, mainly at depths from 4 to 13 km beneath the centre of Lake Taupō. The earthquakes in the last 2 weeks, the largest of which was magnitude 3.6 on 4 November, have been concentrated in the central portion of the lake, south of Horomatangi Reef. Figure 1 shows the number of earthquakes detected beneath Lake Taupō each week since early 2022.
Figure 1 Number of earthquakes detected and located beneath Lake Taupō each week since the start of 2022.
In addition to seismic activity, we also continuously monitor ground deformation (land movement) around Lake Taupō. Our GNSS (GPS) instruments around the lake continue to observe both horizontal and vertical changes. A site on Horomatangi Reef in the centre of the lake indicates that uplift at a rate of approximately 60 ± 20 mm per year has continued since May 2022 (Figure 2).
Figure 2: GNSS ground uplift observed at Horomatangi Reef in central Lake Taupō since 2020. The observations represent daily elevations. The scatter in the observations reflects the uncertainty in the calculated daily elevations. The GNSS site at Horomatangi Reef was not operating from mid-2021 to mid-2022.
We interpret the ground deformation and earthquake activity to be caused by activity associated with magma and hydrothermal fluids inside the volcano. This activity could continue for the coming weeks or months at varying rates or intensities. While some of the earthquakes have been felt in areas around Lake Taupō, the deformation is currently only detectable by our sensitive ground-based monitoring instruments.
In broad terms, such volcanic unrest occurs when magma or magma-heated hot water and steam moves deep within the ground beneath a volcano, changing the stresses there and producing earthquakes and ground movement. There have been 17 previous episodes of unrest at Taupō over the past 150 years and none have resulted in an eruption. Check out more about this in our recent Q&A about Taupō volcano.
GNS Science, through the GeoNet programme, continually monitors Taupō volcano and our other active volcanoes for signs of activity. The Volcanic Alert Level (VAL) was raised to Level 1 for Taupō Volcano on 20 September 2022. This was based on the current data but was also supported by new knowledge from research programmes on volcanic eruptions and unrest at Taupō Volcano. Watch a video with an update on what's been happening at Taupō volcano since the VAL was increased to Level 1 here.
The Volcanic Alert Level reflects the current level of volcanic unrest or activity and is not a forecast of future activity. While Volcano 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.
The Tūwharetoa Māori Trust Board (CEO Rakeipoho Taiaroa) is closely involved in discussions as the landowner of Lake Taupō. More information about the Trust can be found at https://www.tuwharetoa.co.nz/.
Although we can’t prevent natural hazards, we can prepare for them – and we should.
During volcanic activity, follow official advice provided by your local Civil Defence Emergency Management Group.
More information about Civil Defence in the Taupō District can be found here.
For information on preparing for earthquakes or responding to volcanic activity, there are guidelines from the National Emergency Management Agency's Get Ready website.
Prepare your home. Protect your whānau.
There’s a lot we can do to make our homes safer and stronger for earthquakes. Toka Tū Ake EQC’s website has key steps to get you started.
Earthquakes can occur anywhere in New Zealand at any time. In the event of a large earthquake: Drop, Cover and Hold.
Find out more about Taupō Volcano
How do we monitor our volcanoes?
Paul Jarvis
Duty Volcanologist
Media Contact: 021 574541 or media@gns.cri.nz