The 1855 Wairarapa earthquake occurred on 23 January at about 9.17 p.m., affecting much of the

Cook Strait Cook Strait ( mi, Te Moana-o-Raukawa) separates the North and South Islands of New Zealand. The strait connects the Tasman Sea on the northwest with the South Pacific Ocean on the southeast. It is wide at its narrowest point,McLintock, A ...

area of

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 coun ...

, including Marlborough in the

South Island The South Island, also officially named , is the larger of the two major islands of New Zealand in surface area, the other being the smaller but more populous North Island. It is bordered to the north by Cook Strait, to the west by the Tasman ...

and

Wellington Wellington ( mi, Te Whanganui-a-Tara or ) is the capital city of New Zealand. It is located at the south-western tip of the North Island, between Cook Strait and the Remutaka Range. Wellington is the second-largest city in New Zealand by ...

and the

Wairarapa The Wairarapa (; ), a geographical region of New Zealand, lies in the south-eastern corner of the North Island, east of metropolitan Wellington and south-west of the Hawke's Bay Region. It is lightly populated, having several rural service ...

in the

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-larges ...

. In Wellington, close to the

epicentre The epicenter, epicentre () or epicentrum in seismology is the point on the Earth's surface directly above a hypocenter or focus, the point where an earthquake or an underground explosion originates. Surface damage Before the instrumental pe ...

, shaking lasted for at least 50 seconds. The

moment magnitude The moment magnitude scale (MMS; denoted explicitly with or Mw, and generally implied with use of a single M for magnitude) is a measure of an earthquake's magnitude ("size" or strength) based on its seismic moment. It was defined in a 1979 pape ...

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 An earthquake (also known as a quake, tremor or temblor) is the shaking of the surface of the Earth resulting from a sudden release of energy in the Earth's lithosphere that creates seismic waves. Earthquakes can range in intensity, fr ...

was associated with the largest observed movement on a strike-slip fault, maximum . It has been suggested that the

surface rupture In seismology, surface rupture (or ground rupture, or ground displacement) is the visible offset of the ground surface when an earthquake rupture along a fault affects the Earth's surface. Surface rupture is opposed by buried rupture, where th ...

formed by this event helped influence

Charles Lyell Sir Charles Lyell, 1st Baronet, (14 November 1797 – 22 February 1875) was a Scottish geologist who demonstrated the power of known natural causes in explaining the earth's history. He is best known as the author of ''Principles of Geolo ...

to link earthquakes with rapid movement on faults.

Tectonic setting

New Zealand lies along the boundary between the

Australian Australian(s) may refer to: Australia * Australia, a country * Australians, citizens of the Commonwealth of Australia ** European Australians ** Anglo-Celtic Australians, Australians descended principally from British colonists ** Aboriginal A ...

and

Pacific Plate The Pacific Plate is an oceanic tectonic plate that lies beneath the Pacific Ocean. At , it is the largest tectonic plate. The plate first came into existence 190 million years ago, at the triple junction between the Farallon, Phoenix, and I ...

s. In the South Island most of the relative displacement between these plates is taken up along a single dextral (right lateral)

strike-slip fault In geology, a fault is a planar fracture or discontinuity in a volume of rock across which there has been significant displacement as a result of rock-mass movements. Large faults within Earth's crust result from the action of plate tectoni ...

with a major reverse component, the

Alpine Fault The Alpine Fault is a geological fault that runs almost the entire length of New Zealand's South Island (c. 480 km) and forms the boundary between the Pacific Plate and the Indo-Australian Plate. The Southern Alps have been uplifted on the f ...

. In the North Island the displacement is mainly taken up along the Kermadec subduction zone, although the remaining dextral strike-slip component of the relative plate motion is accommodated by the North Island Fault System (NIFS). A group of dextral strike-slip structures, known as the

Marlborough Fault System 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 Alpin ...

, transfer displacement between the mainly

transform Transform may refer to: Arts and entertainment * Transform (scratch), a type of scratch used by turntablists * ''Transform'' (Alva Noto album), 2001 * ''Transform'' (Howard Jones album) or the title song, 2019 * ''Transform'' (Powerman 5000 album ...

and convergent type plate boundaries in a complex zone at the northern end of the South Island. The earthquake occurred on the

Wairarapa Fault 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 pa ...

which is part of the NIFS.

Earthquake characteristics

The earthquake was associated with the rupturing of approximately of the Wairarapa Fault. A horizontal displacement of up to was accompanied by uplift and tilting of the Rimutaka Range on the northwestern side of the fault with vertical offsets of about 6 metres near the fault reducing to almost nothing on the western coast of the Wellington Peninsula. The estimated magnitude of about 8.2 is unusually large for an earthquake associated with movement on a mainly strike-slip fault, and the coseismic offset would have been the largest known for such an event. It has been suggested that this was caused by the rupture propagating down to where the fault links through to the top of the subducting Pacific Plate.

Geomorphological Geomorphology (from Ancient Greek: , ', "earth"; , ', "form"; and , ', "study") is the scientific study of the origin and evolution of topographic and bathymetric features created by physical, chemical or biological processes operating at or ...

evidence, particularly the uplifted beach ridges observed at Turakirae Head, appears to record three previous coseismic uplifts of the Rimutaka Range caused by earthquakes similar in magnitude to the 1855 event, with a recurrence interval of about 2200 years.

Damage

Landslip_caused_by_earthquake_near_Wellington

Wellington experienced severe shaking but the resulting damage was reduced as the city had been extensively rebuilt following the

1848 Marlborough earthquake 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. In Wellington, the shaking lasted for about two mi ...

using mainly wooden structures; only one recorded fatality (by collapse of a brick chimney) occurred, though several other buildings were damaged. Reports identify at least another four people (possibly as many as eight) as having died in the Wairarapa during the earthquake and a bridge over the Hutt River was wrecked. Numerous landslides were associated with the earthquake, including the harbour-side cliffs near

Newlands Newlands may refer to: Places Australia * Newlands, Queensland, a locality in the Whitsunday Region New Zealand * Newlands, Wellington, a suburb of Wellington South Africa * Newlands, Cape Town, a suburb of Cape Town * Newlands, Johannesbu ...

and numerous events along the slopes of the Rimutaka Range. Minor damage was recorded in places as far away as

New Plymouth New Plymouth ( mi, Ngāmotu) is the major city of the Taranaki region on the west coast of the North Island of New Zealand. It is named after the English city of Plymouth, Devon from where the first English settlers to New Plymouth migrated. Th ...

, Lyttelton and

Christchurch Christchurch ( ; mi, Ōtautahi) is the largest city in the South Island of New Zealand and the seat of the Canterbury Region. Christchurch lies on the South Island's east coast, just north of Banks Peninsula on Pegasus Bay. The Avon Rive ...

. The uplift of the northwestern side of Wellington Harbour rendered many of the jetties in the harbour unusable, although this new area of land provided a new rail and road route to the north. Much of modern Wellington's

central business district A central business district (CBD) is the commercial and business centre of a city. It contains commercial space and offices, and in larger cities will often be described as a financial district. Geographically, it often coincides with the "city ...

is formed by reclamations on land raised from the harbour by the event, as shown by the series of "Shoreline 1840" plaques. At Turakirae Head the newest

raised beach A raised beach, coastal terrace,Pinter, N (2010): 'Coastal Terraces, Sealevel, and Active Tectonics' (educational exercise), from 2/04/2011/ref> or perched coastline is a relatively flat, horizontal or gently inclined surface of marine origin, ...

was formed by an uplift of in the 1855 quake. Along with other historic earthquakes in the Wellington region, the severe uplift and landslides along the coastline caused by the 1855 Wairarapa earthquake would have likely extirpated local populations of ''

Durvillaea antarctica ''Durvillaea antarctica'', also known as ' and ', is a large, robust species of southern bull kelp found on the coasts of Chile, southern New Zealand, and Macquarie Island.Smith, J.M.B. and Bayliss-Smith, T.P. (1998). Kelp-plucking: coastal eros ...

'' southern bull kelp. For comparison, a large-scale die off of ''Durvillaea'' was observed following the

2016 Kaikōura earthquake The 2016 Kaikoura earthquake was a magnitude 7.8 (Mw) earthquake in the South Island of New Zealand that occurred two minutes after midnight on 14 November 2016 NZDT (11:02 on 13 November UTC). Ruptures occurred on multiple faults and the ...

. The removal of ''D. antarctica'' along the Wellington coastline in 1855 (or earlier) would have created an ecological opportunity, which may have facilitated a northward

range expansion Colonisation or colonization is the process in biology by which a species spreads to new areas. Colonisation often refers to ''successful'' immigration where a population becomes integrated into an ecological community, having resisted initia ...

for '' Durvillaea poha'' from the South Island.

Tsunami

The earthquake generated New Zealand's largest historical locally generated

tsunami A tsunami ( ; from ja, 津波, lit=harbour wave, ) is a series of waves in a water body caused by the displacement of a large volume of water, generally in an ocean or a large lake. Earthquakes, volcanic eruptions and other underwater exp ...

, with a maximum run-up of . New Zealand's

National Institute of Water and Atmospheric Research The National Institute of Water and Atmospheric Research or NIWA ( mi, Taihoro Nukurangi), is a Crown Research Institute of New Zealand. Established in 1992, NIWA conducts research across a broad range of disciplines in the environmental scien ...

created an animated tsunami simulation model based on the 1855 Wairarapa event, which was screened on the television tele-drama "Aftershock".NIWA tsunami animation
– National Institute of Water and Atmospheric Research

Tectonic setting

Earthquake characteristics

Damage

Tsunami

See also

References

Further reading