Wairarapa Fault

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Wairarapa Fault
NIFS.png
Wairarapa Fault (orange) in context main strands of North Island Fault System.
Wairarapa Fault
 
Map of active Wairarapa Fault traces (red)
Etymology Wairarapa
Country New Zealand
Region Wairarapa Region
Characteristics
Range Rimutaka Range
Segmentsmultiple
Lengthover 120 km (75 mi) on shore, likely 160 km (99 mi) in total [1]
Strike reverse northeast trending [1] [2]
Dip steeply northwest [1]
Displacement up to 11.5 mm (0.45 in)/year ± 0.5 mm (0.020 in)/year [1]
Tectonics
Plate Australian
Status Active
Earthquakes 1855 Wairarapa earthquake
Type Dextral fault
Movement Mw 8.1, [1] maximum slip in 1855 was 18.7 m (61 ft) with up to 2.7 m (8 ft 10 in) of vertical displacement [1]
Age Miocene-Holocene
New Zealand geology database (includes faults)

The Wairarapa Fault is an active seismic fault in the southern part of the North Island of New Zealand. It is a dextral (right lateral) strike-slip fault with a component of uplift to the northwest as expressed by the Rimutaka Range. It forms part of the North Island Fault System, which accommodates the transfer of displacement along the oblique convergent boundary between the Indo-Australian Plate and Pacific Plate. [3]

Contents

Geometry

The Wairarapa Fault continues south of Lake Wairarapa as the Wharekauhau thrust, which can be traced on the seabed in the Cook Strait for about 30 km with a possible further continuation on a fault strand lying to the northwest. These faults segments are considered likely to be the active traces of the southern Wairarapa Fault. [4] At its northeastern end the fault terminates near Mauriceville, with the displacement apparently continued on the Pa Valley and Alfredton Faults. [5]

Seismicity

Rupture along the Wairarapa Fault and Wharekauhau thrust was responsible for the 1855 Wairarapa earthquake that initiated at the southern tip of the faults, resulting in 20 m (66 ft) slip maximum, a local peak of 8 m (26 ft) vertical displacement and magnitude of at least Mw 8.1. [2] There is also evidence from trenching that the rupture continued onto the Alfredton Fault. [5] [1] The uplifted beach ridges of Turakirae Head provide a proxy record of prehistoric earthquakes. This record has been checked by trenching across parts of the Wairarapa Fault. The trenching recorded five surface rupturing events since about 5,500 years BP, the last of which is the 1855 earthquake and two of which are not recorded by beach ridges. Together the observations give a mean recurrence interval of about 1,200 years. [6] Lidar studies have increased the number of significant whole fault earthquakes to eight and suggest they are all great earthquakes producing a mean lateral slip of 16.5 ± 2.2 m (54.1 ± 7.2 ft). [2]

Risk

It appears that the Wairarapa fault is interacting with at least the Kekerengu, Needles and Awatere faults across Cook Strait to the south, in that at least 3 ruptures there preceded by several years these major earthquakes and presumably loaded the Wairarapa Fault. [2] The 1848 Marlborough earthquake in the southern island preceded the 1855 Wairarapa earthquake earthquake by seven years. [2] It is known that the 2016 Kaikōura earthquake loaded the southern part of the fault, [2] but as already mentioned the mean recurrence interval is 1,230 ± 190 years. [6] There is a high probability that the next rupture will be a great earthquake. [6]

See also

Related Research Articles

<span class="mw-page-title-main">Alpine Fault</span> Right-lateral strike-slip fault, that runs almost the entire length of New Zealands South Island.

The Alpine Fault is a geological fault that runs almost the entire length of New Zealand's South Island, being about 600 km (370 mi). long, and forms the boundary between the Pacific Plate and the Australian Plate. The Southern Alps have been uplifted on the fault over the last 12 million years in a series of earthquakes. However, most of the motion on the fault is strike-slip, with the Tasman district and West Coast moving north and Canterbury and Otago moving south. The average slip rates in the fault's central region are about 38 mm (1.5 in) a year, very fast by global standards. The last major earthquake on the Alpine Fault was in about 1717 AD with a great earthquake magnitude of Mw8.1. The probability of another one occurring within the next 50 years is estimated at 75 percent.

<span class="mw-page-title-main">Paleoseismology</span> Study of earthquakes that happened in the past

Paleoseismology looks at geologic sediments and rocks, for signs of ancient earthquakes. It is used to supplement seismic monitoring, for the calculation of seismic hazard. Paleoseismology is usually restricted to geologic regimes that have undergone continuous sediment creation for the last few thousand years, such as swamps, lakes, river beds and shorelines.

<span class="mw-page-title-main">Hope Fault</span> Active fault in New Zealand

The Hope Fault is an active dextral strike-slip fault in the northeastern part of South Island, New Zealand. It forms part of the Marlborough Fault System, which accommodates the transfer of displacement along the oblique convergent boundary between the Indo-Australian Plate and Pacific Plate, from the transform Alpine Fault to the Hikurangi Trench subduction zone.

<span class="mw-page-title-main">San Jacinto Fault Zone</span> Southern Californian fault zone

The San Jacinto Fault Zone (SJFZ) is a major strike-slip fault zone that runs through San Bernardino, Riverside, San Diego, and Imperial Counties in Southern California. The SJFZ is a component of the larger San Andreas transform system and is considered to be the most seismically active fault zone in the area. Together they relieve the majority of the stress between the Pacific and North American tectonic plates.

The 1855 Wairarapa earthquake occurred on 23 January at about 9.17 p.m., affecting much of the Cook Strait area of New Zealand, including Marlborough in the South Island and Wellington and the Wairarapa in the North Island. In Wellington, close to the epicentre, shaking lasted for at least 50 seconds. The moment magnitude of the earthquake has been estimated as 8.2, the most powerful recorded in New Zealand since systematic European colonisation began in 1840. This earthquake was associated with the largest directly observed movement on a strike-slip fault, maximum 18 metres (59 ft). This was later revised upward to about 20 m (66 ft) slip, with a local peak of 8 m (26 ft) vertical displacement on lidar studies. It has been suggested that the surface rupture formed by this event helped influence Charles Lyell to link earthquakes with rapid movement on faults.

The 1848 Marlborough earthquake was a 7.5 earthquake that occurred at 1:40 a.m. on 16 October 1848 and whose epicentre was in the Marlborough region of the South Island of New Zealand.

<span class="mw-page-title-main">Marlborough fault system</span> Active fault system in New Zealand

The Marlborough fault system is a set of four large dextral strike-slip faults and other related structures in the northern part of South Island, New Zealand, which transfer displacement between the mainly transform plate boundary of the Alpine fault and the mainly destructive boundary of the Kermadec Trench, and together form the boundary between the Australian and Pacific Plates.

<span class="mw-page-title-main">Wairau Fault</span> Active fault in New Zealand

The Wairau Fault is an active dextral strike-slip fault in the northeastern part of South Island, New Zealand. It forms part of the Marlborough Fault System, which accommodates the transfer of displacement along the oblique convergent boundary between the Indo-Australian Plate and Pacific Plate, from the transform Alpine Fault to the Hikurangi Trench subduction zone.

<span class="mw-page-title-main">Awatere Fault</span>

The Awatere Fault is an active dextral strike-slip fault in the northeastern part of South Island, New Zealand. It forms part of the Marlborough Fault System, which accommodates the transfer of displacement along the oblique convergent boundary between the Indo-Australian Plate and Pacific Plate, from the transform Alpine Fault to the Hikurangi Trench subduction zone. The 1848 Marlborough earthquake was caused by rupture of the whole of the eastern section of the Awatere Fault.

<span class="mw-page-title-main">Clarence Fault</span> Active fault in New Zealand

The Clarence Fault is an active dextral strike-slip fault in the northeastern part of South Island, New Zealand. It forms part of the Marlborough Fault System, which accommodates the transfer of displacement along the oblique convergent boundary between the Indo-Australian Plate and Pacific Plate, from the transform Alpine Fault to the Hikurangi Trench subduction zone.

<span class="mw-page-title-main">North Island Fault System</span> Fault zone of the east coast of New Zealands North Island

The North Island Fault System (NIFS) is a set of southwest–northeast trending seismically-active faults in the North Island of New Zealand that carry much of the dextral strike-slip component of the oblique convergence of the Pacific Plate with the Australian Plate. However despite at least 3 km (1.9 mi) of uplift of the axial ranges in the middle regions of the fault system during the last 10 million years most of the shortening on this part of the Hikurangi Margin is accommodated by subduction.

<span class="mw-page-title-main">Wellington Fault</span> Active seismic fault in New Zealand

The Wellington Fault is an active seismic fault in the southern part of the North Island of New Zealand. It is a dextral (right-lateral) strike-slip fault with variable amounts of vertical movement causing uplift to the northwest, as expressed by a series of ranges. It forms part of the North Island Fault System, which accommodates the transfer of displacement along the oblique convergent boundary between the Indo-Australian Plate and Pacific Plate.

The 1934 Pahiatua earthquake struck at 11:46 pm on 5 March, causing severe damage in much of the lower North Island. Wairarapa, Wellington and Hawke's Bay felt the strongest levels of shaking, with much of New Zealand feeling the tremor.

The 1863 Hawke's Bay earthquake was a devastating magnitude 7.5 Mw earthquake that struck near the town of Waipukurau on 23 February 1863. It remained the single largest earthquake to strike Hawke's Bay until 1931, where a magnitude 7.8 quake leveled much of Napier and Hastings, and killed 256 people.

<span class="mw-page-title-main">Hikurangi Margin</span> Subduction zone off the east coast of New Zealands North Island

The Hikurangi Margin is New Zealand's largest subduction zone and fault.

<span class="mw-page-title-main">Kekerengu Fault</span> Active fault in New Zealand

The Kekerengu Fault is an active dextral strike-slip fault in the northeastern part of South Island, New Zealand. It is closely associated with the Hope Fault and Jordan Thrust at its south-easternmost edge and likely joins with the Clarence Fault to form the Wairarapa Fault offshore in Cook Strait.

<span class="mw-page-title-main">Paeroa Fault</span> Active fault in New Zealand

The Paeroa Fault is a seismically active area in the Taupō District, Waikato Region of the central North Island of New Zealand.

The Taupō Fault Belt contains many almost parallel active faults, and is located in the Taupō Rift of the central North Island of New Zealand geographically between Lake Taupō and the lakes of Rotorua, Tarawera, Rotomahana and Rerewhakaaitu. The potential active fault density is very high, with only 0.1 to 1 km 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.

The Rangipo Fault is the eastern Taupō rift-bounding north–south striking normal fault complex of the Ruapehu Graben, a seismically active area of the central North Island of New Zealand to the west of Mount Ruapehu. It could be part of a Mw7.1 potential rupture.

<span class="mw-page-title-main">Otago fault system</span>

The Otago fault system contains multiple faults with the potential to have rupture events greater than Mw7 in magnitude. These are parallel to, and to the east of the Alpine Fault in the south eastern part of the South Island of New Zealand. It accommodates about 2 mm (0.079 in)/year of contraction.

References

  1. 1 2 3 4 5 6 7 Rodgers, D.W.; Little T.A. (2006). "World's largest coseismic strike-slip offset: The 1855 rupture of the Wairarapa Fault, New Zealand, and implications for displacement/length scaling of continental earthquakes". Journal of Geophysical Research. 111 (B12408): n/a. Bibcode:2006JGRB..11112408R. doi:10.1029/2005JB004065 . Retrieved 5 October 2010.
  2. 1 2 3 4 5 6 Manighetti, I; Perrin, C; Gaudemer, Y; Dominguez, S; Stewart, N; Malavieille, J; Garambois, S (2020). "Repeated giant earthquakes on the Wairarapa fault, New Zealand, revealed by Lidar-based paleoseismology". Scientific Reports. 10 (2124). doi:10.1038/s41598-020-59229-3. PMC   7005692 .
  3. Mouslopoulou, V.; Nicol, A.; Little, T.A.; Begg J.A. (2009). "Palaeoearthquake surface rupture in a transition zone from strike-slip to oblique-normal slip and its implications to seismic hazard, North Island Fault System, New Zealand". In Reicherter K., Michetti A.M. & Silva P.G. (ed.). Palaeoseismology: historical and prehistorical records of earthquake ground effects for seismic hazard assessment. Special Publications. Vol. 316. London: Geological Society. pp. 269–292. ISBN   978-1-86239-276-2 . Retrieved 3 October 2010.
  4. Barnes, P.M. (January 2005). "The southern end of the Wairarapa Fault, and surrounding structures in Cook Strait" (PDF). In Townend J., Langridge R. & Jones A. (ed.). The 1855 Wairarapa Earthquake Symposium: 150 years of thinking about magnitude 8+ earthquakes and seismic hazard in New Zealand. Greater Wellington Regional Council. pp. 66–71. ISBN   0-909016-87-9.
  5. 1 2 Schermer, E.R.; Van Dissen R.; Berryman K.R.; Kelsey H.M.; Cashman S.M. (2004). "Active faults, paleoseismology, and historical fault rupture in northern Wairarapa, North Island, New Zealand" (PDF). New Zealand Journal of Geology & Geophysics. 47: 101–122. doi:10.1080/00288306.2004.9515040. S2CID   128549630 . Retrieved 5 October 2010.
  6. 1 2 3 Van Dissen, R.; Berryman, K.; King, A.; Webb, T.; Brackley, H.; Barnes, P.; Beavan, J.; Benites, R.; Barker, P.; Carne, R.; Cochran, U.; Dellow, G.; Fry, B.; Hemphill-Haley, M.; Francois-Holden, C.; Lamarche, G.; Langridge, R.; Litchfield, N.; Little, T.; McVerry, G.; Ninis, D.; Palmer, N.; Perrin, N.; Pondard, N.; Semmens, S.; Stephenson, W.; Robinson, R.; Villamor, P.; Wallace, L.; Wilson, K. (2009). "It's Our Fault: Better Defining the Earthquake Risk in Wellington – Results to Date & a Look to the Future" (PDF). NZEE Conference Proceedings. Retrieved 6 October 2010.