Manawahe Fault

Active fault in New Zealand

Manawahe Fault

Approximate surface traces of the active Manawahe Fault in red in the Taupō Rift, North Island, New Zealand[1]

Etymology| Manawahe
Coordinates| 37°57′50″S 176°40′16″E﻿ / ﻿37.964°S 176.671°E﻿ / -37.964; 176.671
Country| New Zealand
Region| Bay of Plenty Region
Characteristics
Range| Mw6.3[2]
Length| 14 km (8.7 mi)[2]
Strike| ENE[2]
Displacement| 3 mm (0.12 in)/yr[2]
Tectonics
Plate| Indo-Australian
Status| Active, recurrence is 1580–2000 years[2]
Type| Normal fault[2]
Age| Holocene ~0.1 Ma

PreꞒ

Volcanic arc/belt| Taupō Volcanic Zone
New Zealand geology database (includes faults)

The Manawahe Fault line is a seismically active area in the Bay of Plenty Region of the central North Island of New Zealand with the potential to be involved with other faults in an Mw7.0 event.[2]

## Geology

[edit]

North of Lake Rotomā, volcanic ignimbrite sheets from multiple eruptions of the Ōkataina Caldera extend towards the Whakatane Graben, with the volcanic region being separated from the tectonic Whakatane portion of the Taupō Rift by the Manawahe Fault.[2] The fault continues to the east and coast in the Matata Fault line. The Manawahe Fault consists of a series of closely-spaced, mainly SSE-dipping fault traces, which are parallel to the North Rotoma Fault at the edge of the north eastern edge of the Rotoma Caldera. The traces are presumed to merge within 3 km (1.9 mi) of the surface.[2] The Manawahe Fault ruptured immediately prior to the 5500 years ago Whakatane eruption of the Ōkataina Caldera and also ruptured several times, associated with the Rotoma Caldera eruptive sequence, and immediately after the Mamaku eruption.[2]

## Risks

[edit]

This intra-rift fault has certainly ruptured several times in the last 10,000 years.[3] The most recent rupture occurred 636 years ago, on a fault within the Taupō Volcanic Zone that has one of the highest known slip rates, with recurrence intervals ranging from 1,580 to 2,000 years.[2] Although potentially ruptures could be up to Mw 7 if the fault ruptured at the same time as the longer Matata fault, only > Mw 5.5 can be definitely assigned on displacements characterised to date as there appears to have never been a single full length fault rupture which would result in a Mw 6.3event.[2]

## References

[edit]

1. ^ "GNS:New Zealand Active Faults Database". Retrieved 7 April 2023.
2. ^ a b c d e f g h i j k l Villamor, P.; Litchfield, N.J.; Gomez, D.; Martin, F.; Alloway, B.; Berryman, K.; Clark, K.; Ries, W.; Howell, A.; Ansell, B. (2022). "Fault ruptures triggered by large rhyolitic eruption s at the boundary between tectonic and magmatic rift segments: the Manawahe Fault, Taupo Rift, New Zealand". Journal of Volcanology and Geothermal Research. 427. Bibcode:2022JVGR..42707478V. doi:10.1016/j.jvolgeores.2022.107478. hdl:2292/59828. S2CID 246258923.
3. ^ Berryman, Kelvin; Villamor, Pilar; Nairn, Ian; Begg, John; Alloway, Brent V.; Rowland, Julie; Lee, Julie; Capote, Ramon (2022). "Volcano-tectonic interactions at the southern margin of the Okataina Volcanic Centre, Taupō Volcanic Zone, New Zealand". Journal of Volcanology and Geothermal Research. 427 (107552). Bibcode:2022JVGR..42707552B. doi:10.1016/j.jvolgeores.2022.107552. hdl:2292/59681. ISSN 0377-0273.

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Seismic faults of New Zealand

North Island|

| North Island Fault System|

* Kaweka Fault
* Mohaka Fault
* Patoka Fault
* Ruahine Fault
* Rukumoana Fault
* Te Whaiti Fault
* Waimana Fault
* Waiohau Fault
* Waiotahi Fault
* Wairarapa Fault
* Wellington Fault
* Wheao Fault
* Whakatane Fault

|

Taupō Volcanic Zone (Taupō Rift)|

* Aratiatia Fault
* Edgecumbe Fault
* Matata Fault
* Manawahe Fault
* Haukari West Whangamata Fault
* Horohoro Fault
* Kaiapo Fault
* Karioi Fault
* Ngapouri-Rotomahana Fault
* National Park Fault
* Ohakune Fault
* Orakonui Fault
* Paeroa Fault
* Poutu Fault Zone
* Puketarata Fault
* Rangipo Fault
* Raurimu Fault
* Taupō Fault Belt
* Thorpe - Poplar Fault
* Upper Waikato Stream Fault
* Wahianoa Fault
* Waihi Fault Zone
* Waipuna Fault

Hauraki Rift|

* Firth of Thames Fault
* Hauraki Fault
* Kerepehi Fault

Auckland regional faults|

* Wairoa North Fault

South Island|

| Alpine Fault|

|

Marlborough fault system|

* Awatere Fault
* Clarence Fault
* Elliott Fault
* Hope Fault
* Kekerengu Fault
* Wairau Fault

Canterbury fault system|

* Hundalee Fault
* Christchurch Fault
* Greendale Fault
* Port Hills Fault
* Ostler Fault Zone

Otago fault system|

* Akatore Fault
* Green Island Fault
* Kaikorai Fault
* Titri Fault
* Hyde Fault

Other|

| Predominantly oceanic faults|

* Kermadec–Tonga subduction zone (Hikurangi Margin)
* Macquarie fault zone

|

* Faults in New Zealand
* List of earthquakes in New Zealand
* Pacific plate
* Indo-Australian plate

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