Earthquake swarm in Taupo Volcanic Zone, New Zealand

A swarm of over 50 earthquakes has been detected in the geothermal area, north of Taupo, since 05:00 UTC on January 30, with the strongest earthquake being M2.9.

GeoNet reported that many earthquakes were found to be ‘unnoticeable’ or ‘weak’ by the automated system. Some residents in Taupo have felt the shaking despite the classification. The sequence is expected to diminish over the coming days though monitoring continues.

The Taupo area, situated within the Taupo Volcanic Zone (TVZ), frequently experiences earthquake swarms because of its complex geological setting.

The ongoing swarm consists of relatively small earthquakes with magnitudes below 2.9 though one event, an M2.9, has generated over 1 000 felt reports. Most of the tremors have been shallow and are intensifying the likelihood of being noticed by people in the vicinity.

A GeoNet earthquake map shows the distribution, with black dots representing the latest earthquakes since January 30, contrasting with red dots indicating those from the past year.

Unlike traditional earthquake sequences that feature a primary large earthquake followed by aftershocks, earthquake swarms consist of multiple small tremors occurring in a concentrated area over hours, days, or weeks. Such swarms are common across New Zealand in the TVZ where geothermal and magmatic activity influence seismic events.

Fluids, such as water or gases from deeper magma sources can migrate along faults and fractures in the crust. The process reduces friction along pre-existing faults and allows slippage that results in seismic activity. In the TVZ, the combination of geothermal activity and deep-seated magmatic processes contributes to frequent swarms.

While the region is home to Taupō, one of the world’s most active rhyolitic caldera volcanoes, there is no current evidence linking this earthquake swarm to increased volcanic activity. Earthquakes in the area often occur because of geothermal and tectonic interactions rather than magmatic intrusion.

GeoNet data indicate that Taupō experienced an episode of volcanic unrest from May 2022 to April 2023, during which more than 1 800 earthquakes were recorded beneath the summit, accompanied by ground deformation. Activity returned to background levels in May 2023, with the Volcanic Alert Level reduced to 0 and the Aviation Color Code remaining at Green.

Most historical eruptions have been small to moderate in scale although Taupō has produced catastrophic eruptions in the past including the Oruanui eruption (around 22 600 years ago) and the 260 CE eruption. The current earthquake swarm is likely related to geothermal activity rather than volcanic unrest.

Authorities emphasize the importance of earthquake preparedness in seismically active regions like Taupō.

Residents should follow the Drop, Cover, and Hold protocol, during a strong earthquake. If an earthquake is long or strong, those near the lakefront should immediately move to higher ground because of the potential for lake disturbances.

Taupō’s caldera, spanning approximately 35 km (22 miles) in diameter, formed after the Oruanui supereruption which produced around 1 170 km³ (281 mi³) of tephra. The last eruption, around 260 CE, produced the Taupō Ignimbrite and was one of the most explosive events in New Zealand’s history.

The TVZ remains an area of geological activity, with multiple geothermal fields, lava domes, and fissure vents contributing to the region’s complex tectonic environment. Rock compositions include major rhyolitic deposits alongside minor dacitic and basaltic formations. The zone is situated within a subduction setting where the Pacific Plate interacts with the Australian Plate.

References:

¹ Taupo – GVP – Accessed on January 31, 2025

² Taupō earthquake swarm – GeoNet – January 31, 2025