The 1934 Pahiatua earthquake struck at 11:46 pm on 5 March, causing severe damage in much of the lower

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 ...

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 ...

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 me ...

and

Hawke's Bay Hawke's Bay ( mi, Te Matau-a-Māui) is a local government region on the east coast of New Zealand's North Island. The region's name derives from Hawke Bay, which was named by Captain James Cook in honour of Admiral Edward Hawke. The region is ...

(which was still recovering from the

1931 Hawke's Bay earthquake Events January * January 2 – South Dakota native Ernest Lawrence invents the cyclotron, used to accelerate particles to study nuclear physics. * January 4 – German pilot Elly Beinhorn begins her flight to Africa. * January 22 – Si ...

) felt the strongest levels of shaking, with much 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 count ...

feeling the tremor. This earthquake has historically been referred to as the

Pahiatua , image_skyline = Market day pahiatua 1st dec 2007 1.JPG , imagesize = , image_caption = , image_flag = , flag_size = , image_seal = , seal_size = , image_shi ...

earthquake, but recent reviews of its epicentre place it closer to the locality of Horoeka. It was felt as far north as

Auckland Auckland (pronounced ) ( mi, Tāmaki Makaurau) is a large metropolitan city in the North Island of New Zealand. The List of New Zealand urban areas by population, most populous urban area in the country and the List of cities in Oceania by po ...

, and the shaking was also felt in the mainland of the northern

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 along the east coast as far as

Dunedin Dunedin ( ; mi, Ōtepoti) is the second-largest city in the South Island of New Zealand (after Christchurch), and the principal city of the Otago region. Its name comes from , the Scottish Gaelic name for Edinburgh, the capital of Scotland. Th ...

. Destructive intensities of VIII (''Severe'') were experienced in an area that extended approximately 8700 km2 over most of the lower North Island, and reached a peak of IX (''Violent'') south-east of Pahiatua, between the small towns of

Pongaroa Pongaroa is a town in the Tararua District, in the southeast of the North Island of New Zealand, 110 kilometres southwest of Hastings and 200 kilometres northeast of Wellington. The nearest town is Pahiatua, 50 kilometres to the west. Popular A ...

and Bideford.

Tectonic setting

The eastern part of North Island lies on the Hikurangi Margin, where the

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 Iza ...

subducting Subduction is a geological process in which the oceanic lithosphere is recycled into the Earth's mantle at convergent boundaries. Where the oceanic lithosphere of a tectonic plate converges with the less dense lithosphere of a second plate, the ...

obliquely beneath the

Australian Plate The Australian Plate is a major tectonic plate in the eastern and, largely, southern hemispheres. Originally a part of the ancient continent of Gondwana, Australia remained connected to India and Antarctica until approximately when India broke ...

. The dextral (right lateral) component of the convergence is accommodated in the overlying plate by a series of dextral

strike-slip faults 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 tectonic ...

, known as the

North Island Fault System The North Island Fault System (also known as North Island Dextral Fault Belt or NIFS) is a set of southwest–northeast trending seismically-active faults in the North Island of New Zealand that carry most of the dextral (right lateral) strike- ...

Earthquake characteristics

The earthquake had an estimated magnitude of 7.6 on the

surface wave magnitude The surface wave magnitude (M_s) scale is one of the magnitude scales used in seismology to describe the size of an earthquake. It is based on measurements of Rayleigh surface waves that travel along the uppermost layers of the Earth. This ma ...

scale and 7.2–7.4 on the

moment magnitude scale 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 ...

. The epicentre was originally assumed to be near Pahiatua, based on the severity of damage, but further analysis of seismograms from the event, the distribution of felt intensities and the location of

aftershock In seismology, an aftershock is a smaller earthquake that follows a larger earthquake, in the same area of the main shock, caused as the displaced crust adjusts to the effects of the main shock. Large earthquakes can have hundreds to thousand ...

s suggested that it was located near Horoeka. Results of trenching across the Waipukaka Fault suggests that this was the causative fault for the earthquake.

Damage

The earthquake was most severe in the Hawke's Bay and northern Wairarapa regions (now the

Tararua District The Tararua District is a district near the south-east corner of New Zealand's North Island that is administered by the Tararua District Council. It has a population of and an area of 4,364.65 km². The Tararua District Council was created b ...

est. 1989), and caused widespread damage from Porangahau to

Castlepoint Castlepoint is a small beachside settlement on the Wairarapa coast of the Wellington Region of New Zealand. It is home to a lighthouse which stands near the top of the northern end of a reef. The reef is about one kilometre long. At the south ...

. Much of this area, particularly towards the east coast, was sparsely populated at the time, but the shaking caused extensive damage in the town of Pahiatua, where a number of poorly constructed buildings were severely damaged or collapsed entirely. Two people with existing health problems died from heart failure, and one person sustained injuries that required hospitalisation. The movement also triggered numerous small landslides in the cliffs along the coast from

Cape Turnagain Cape Turnagain is a prominent headland on the east coast of New Zealand's North Island, part way between Hawke Bay and Cook Strait, between the mouths of the Porangahau and Ākitio Rivers. The cape was named by Captain James Cook in 1769. On ...

to Castlepoint, and deformed the ground surface in a number of localities.

Notes

External links

* {{Earthquakes in 1934 Pahiatua earthquake 1934 earthquakes Earthquakes in New Zealand

Tectonic setting

Earthquake characteristics

Damage

See also

Notes

Further reading

External links