Taupo Volcano

Taupo from Taupo-nui-a–Tia meaning the ‘great cloak of Tia’. In Māori mythology Tia discovered the lake.

Lake Taupo

Lake Taupo

For a one page fact sheet / poster on Taupo Volcano click VolcanoFactSheets Taupo.pdf (541.34 kB)

Taupo is a ‘supervolcano’ and one of the most frequently active and productive rhyolite caldera in the world. The huge caldera (collapse crater) has been partly filled by New Zealand’s largest lake, Lake Taupo. The caldera is created by subsidence of the ground surface due to emptying of the magma chamber in huge eruptions. The present magma chamber is between 6 and 8 km below the lake.

Although Taupo Volcano has much more violent eruptions than cone volcanoes, they are fortunately less frequent. It began erupting about 300,000 years ago and the present day caldera was created by an eruption 27,000 years ago called the Oruanui Eruption. Between this and the ‘Taupo Eruption’ (1800 years ago) there were at least 26 much smaller eruptions which formed lava domes and spread pumice and ash over nearby areas.

The Taupo Eruption was the most violent eruption known in the world in the last 5000 years. The eruption plume reached 50km into the air, well into the stratosphere. All of New Zealand received at least 1cm of ash, with areas near the lake being buried in more than 100 metres of pyroclastic flow. This scorching hot flow spread up to 90 km from the vent and covered all local features except Ruapehu. it is possible that ash from this eruption was the cause of red sunsets recorded by the Romans and Chinese at that time.

99% of the material erupted from Taupo is pumice and ash which has exploded violently to form pyroclastic ash falls and flow deposits. When the flow deposits are hot enough they become re-melted to create a rock type called welded ignimbrite. The remaining 1% of the magma has lost enough gas to flow rather than explode and forms small lava domes such as Mt Tauhara. Deposits from the Taupo eruption blocked the lake outlet, raising the lake 34 metres above its modern level. When this blockage failed, a catastrophic flood was released down the Waikato River. Layered cliffs of light coloured ignimbrite rock, looser tephra (pumice and ash) and evidence of old shorelines are now found around the lake.

Depending on the severity of future eruption we could expect to see:

  • strong earthquakes causing ground deformation
  • lahars of loose pumice and ash deposits flowing down rivers after eruptions
  • increased activity in geothermal areas, including steam explosions
  • advanced warning through geonet monitoring

GNS Science is monitoring the Taupo Volcano with 7 seismographs and 6 continuous GPS stations, as well as lake levelling at 22 sites.