The Taupō Fault Belt contains many almost parallel active faults, and is located in the

Taupō Rift The Taupō Rift is the seismically active rift valley containing the Taupō Volcanic Zone, central North Island of New Zealand. Geology The Taupō Rift (Taupo Rift) is a intra-arc continental rift resulting from an oblique convergence in the Hik ...

of the central

North Island The North Island, also officially named Te Ika-a-Māui, is one of the two main islands of New Zealand, separated from the larger but much less populous South Island by the Cook Strait. The island's area is , making it the world's 14th-largest ...

New Zealand New Zealand ( mi, Aotearoa ) is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and over 700 smaller islands. It is the sixth-largest island count ...

geographically between

Lake Taupō Lake Taupō (also spelled Taupo; mi, Taupō-nui-a-Tia or ) is a large crater lake in New Zealand's North Island, located in the caldera of the Taupō Volcano. The lake is the namesake of the town of Taupō, which sits on a bay in the lake's nor ...

and the lakes of

Rotorua Rotorua () is a city in the Bay of Plenty region of New Zealand's North Island. The city lies on the southern shores of Lake Rotorua, from which it takes its name. It is the seat of the Rotorua Lakes District, a territorial authority encompass ...

, Tarawera,

Rotomahana Lake Rotomahana is an lake in northern New Zealand, located 20 kilometres to the south-east of Rotorua. It is immediately south-west of the dormant volcano Mount Tarawera, and its geography was substantially altered by a major 1886 eruption of Mo ...

and Rerewhakaaitu. The potential active fault density is very high, with only separating the north-east to south-west orientated normal fault strands on detailed mapping of part of the belt. The Waikato River bisects the western region of the belt.

Geology

The northern Taupō Fault Belt is in the area also referred to as either, the Paeroa Graben or the Kapenga Graben, between the Horohoro Fault and the

Paeroa Fault The Paeroa Fault is a seismically active area in the Taupō District, Waikato, Waikato Region of the central North Island of New Zealand. Geology North of Lake Taupō, volcanic ignimbrite at least thick, and called the Paeroa Ignimbrite (dat ...

. Aligned with the orientation of the modern

are multiple north-north-east trending normal faults. These include the Ngakuru Fault to the east with the Ngakuru Graben between it and the Whirinaki Fault. Within the wide Ngakuru Graben are also to the west the Maleme Fault (Zone), which as a zone also contains the Mangaete/Lakeside Fault and to the east the Hossack Road Fault and the Te Weta Fault. The tectonic activity is driven by the ground subsiding at a rate of since 61,000 years ago with largely orthogonal rifting associated with subduction and the clockwise rotation of the northern North Island allowing the rift to open. The southern Taupō Fault Belt is bounded to the west by a zone of faults that include the Thorpe - Poplar Fault in the north and the Whangamata fault zone. Between these faults and the eastern edge of the belt bounded by the Aratiatia fault zone to the north and the Rotokawa Fault to the south there are many intra-rift faults associated with the active extension by /year ± . This is similar to the case in the northern Taupō Fault Belt and modern earthquake swarm analysis allows many of these faults to be assigned to distinct zones. Accordingly there is a Kaiapo fault zone just to the west of the town of Taupō and the Ngangiho fault zone just to the east of Kinloch with between them a Whakaipo fault zone. Also active in the north of the southern Taupō Fault Belt are the Puketarata, Orakeikorako, Lake Ohakuri, Tuahu and the Orakonui Faults. Detailed mapping, supplemented by deep ground trenching, of a portion of the southern Taupō Fault Belt prior to construction of a geothermal power station not only showed how inaccurate the inferred active fault tracings in this area are, with under counting potential active fault strands by a factor of perhaps two, it also caused the relocation of the power station.

Tectonic Volcanic Relationships

There are discontinuities in the definable faults of the modern Taupō Rift imposed by its caldera's, with the Taupō Volcano and the Ōkataina Volcanic Centre at the southern and northern end of the Taupō Fault Belt respectively defining the limits of its predominant tectonic activity. Tectonic activity predominates in the present rift also south of

until the active andesitic volcanoes of the North Island Volcanic Plateau are reached or from the

Ōkataina Caldera Ōkataina Caldera (Ōkataina Volcanic Centre, also spelled Okataina) is a massive, recently active volcanic caldera and its associated volcanoes located in Taupō Volcanic Zone of New Zealand's North Island. It is just east of the smaller Rotoru ...

north through the

Whakatāne Graben The Whakatāne Graben (also Whakatane Graben) is a predominantly normal faulting tectonic feature of the northeastern aspect of the young, modern Taupō Rift in New Zealand. At the coast it is widening by about /year. This very geologically acti ...

to the active andesitic volcano of

Whakaari / White Island Whakaari / White Island (, mi, Te Puia Whakaari, lit. "the dramatic volcano"), also known as White Island or Whakaari, is an active andesite stratovolcano situated from the east coast of the North Island of New Zealand, in the Bay of Plent ...

. The recently active vents in the main volcanoes are not aligned with currently active faults in the Taupō Fault Belt but there are interactions and for example there was a complete fault rupture of the Ngapouri-Rotomahana Fault just prior to the 1314±12 CE Kaharoa eruption of

Mount Tarawera Mount Tarawera is a volcano on the North Island of New Zealand within the older but volcanically productive Ōkataina Caldera. Located 24 kilometres southeast of Rotorua, it consists of a series of rhyolitic lava domes that were fissured d ...

. The 2001 Taupō earthquake swarm started within a very constrained area of the Taupō Volcano under the northwestern portion of Lake Taupō within the Oruanui caldera. It spread out horizontally over time with small size predominantly strike-slip faulting constrained to zones associated with the tectonic normal faults. This is consistent with a

mafic A mafic mineral or rock is a silicate mineral or igneous rock rich in magnesium and iron. Most mafic minerals are dark in color, and common rock-forming mafic minerals include olivine, pyroxene, amphibole, and biotite. Common mafic rocks include ...

magma intrusion (rather than one associated with the rhyolytic eruptions of Taupō) causing pressure over predominantly time, rather than place perpendicular to the usual strain on these fault systems and has been seen elsewhere. This is consistent with seismicity rather than volcanic activity poses the main short-term hazard at Taupō Volcano.

References

{{Rotorua District Seismic faults of New Zealand Taupō Volcanic Zone Taupō District Rotorua Lakes District Seismic zones of New Zealand