Rotorua Volcano | John Seach


Rotorua, New Zealand

38.08 S, 176.27 E
summit elevation 757 m

Rotorua volcano is located in the taupo volcanic zone of the North Island, New Zealand. A caldera forming eruption occurred 220,000 years ago. Rotorua ash has been found as far away as Hamilton and Taupo.

Rotorua contains a geyser located at Te Whakarewarewatangaoteopetauaawahiao.

Rotorua Geothermal Field
Exploitation of water in the geothemal system led to a decline in hydrothemal activity in the 1980's. Since the mid 1980's closure of wells in Rotorua led to an increase in activity at geysers.

Lake Rotorua - John Seach

rotorua volcano
Te Werenga, Rotorua - John Seach

rotorua volcano
Pohutu geyser, Rotorua - John Seach

Mud pot Rotorua volcano

Large Hydrothermal Eruption in 2005
One of the largest hydrothermal eruptions at Rotorua since 1948 occurred on 19th April 2005. The eruption was observed by two farmers who witnessed a column of steam, mud and rocks ejected 200 m into the air. The eruption created a 50 m wide crater.

2003 Hydrothermal Eruptions
Two hydrothermal eruptions occurred at Kuirau Park on 6th November 2003. The explosion mud, rock, and ash 14 m into the air, and destroyed trees around the crater.

2001 Hydrothermal Eruption
A hydrothermal eruption occurred at Rotorua on 26th January 2001. This was the largest hydrothermal eruption since 1966. A hot muddy pool 3 m in diameter in Kuirau park was the source of the eruption. Blocks and ejecta were thrown 100 m high and 1 m diameter blocks were thrown 50 m away.

2000 Hydrothermal Eruption
On 18th September 2000, spring 653 erupted, producing waves and surges. The eruption occurred on private land and may have been caused by removal of a clothesline pole and anchoring concrete block three days earlier.

Fatalities from Hydrogen sulphide poisoning.
Fatal hydrogen sulphide poisoning has occurred at Rotorua in 1946, 1948, 1954, 1962, and 1987.

Eruption 13,800 years ago
A Plinian eruption generated more than 10,000 cubic km of material.

Okareka Ash eruption
This eruption occurred 18,000 years ago.

Mamaku Ignimbrite (140 ka)
The eruption formed a 15 km wide caldera, and was followed by effusive rhyolite eruptions which built lava flow and dome complexes, in the southern part of the caldera. Inside the caldera the ignimbrite is up to 1 km deep.

Further reading
Nairn, I.A., 1980. Source, age, and eruptive mechanisms of Rotorua Ash. New Zealand journal of geology and geophysics23(2), pp.193-207.

Healy, J., 1963, January. Geology of the Rotorua district. In Proceedings (New Zealand Ecological Society) (Vol. 10, No. 10, pp. 53-58). New Zealand Ecological Society.

Rotorua Volcano Eruptions

Currently hydrothermal activity.
13,800 years ago
25,000 years ago.