1931 Hawke's Bay earthquake

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**1931 Hawke's Bay earthquake**

Date	February 3, 1931 (1931-02-03)
Magnitude	7.9 M_w
Countries/ regions affected	New Zealand
Tsunami:	none
Casualties:	256 dead

Tectonic map of New Zealand with the interpreted position of the Napier Fault highlighted

Damage to the Hawkes Bay Tribune building

Damage to the Hastings Post Office

The 1931 Hawke's Bay earthquake, also known as the Napier earthquake, occurred in New Zealand at 10:47 am on Tuesday February 3, 1931, killing 256^[1] and devastating the Hawke's Bay region. Centred 15 km north of Napier, it lasted for two and a half minutes and was estimated to have measured about 7.8 on the Richter scale, and 7.9 on the modern Richter Scale. The earthquake struck with a massive upthrust, and half a minute later came a huge resettling. There were 525 aftershocks recorded in the following two weeks. The main shock could be felt in much of the lower half of the North Island.

1 Tectonic setting
2 Effects
3 Rebuilding
4 See also
5 References & notes
6 External links

[edit] Tectonic setting

New Zealand lies along the boundary between the Australian and Pacific Plates. In South Island most of the relative displacement between these plates is taken up along a single dextral (right lateral) strike-slip fault with a major reverse component, the Alpine Fault. In 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).^[2]

The earthquake occurred on the Napier Fault which is one of the larger thrust structures within the accretionary wedge formed above the Kermadec subduction zone ^[3].

[edit] Effects

Nearly all buildings in the central areas of Napier and Hastings were levelled (The Dominion noted that "Napier as a town has been wiped off the map")^[4] and the death toll included 161 people in Napier, 93 in Hastings, and two in Wairoa.^[1] Thousands more were injured, with over 400 hospitalised. The local landscape changed dramatically, with the coastal areas around Napier being lifted by around two metres.^[4] Some 40 km² of sea-bed became dry land, where the airport, housing and industrial property developments now exist.

The most noticeable land change was the uplifting of the Ahuriri Lagoon. The lagoon was lifted more than 2.7 metres,^[4] which resulted in draining 2230 hectares of the lagoon. Today, the area is where farmland and the Hawkes Bay Airport is located.

Within minutes fires broke out in chemist shops in Hastings Street. The fire brigade almost had the first fire under control when the second broke out in a shop at the back of the Masonic Hotel. The hotel was quickly engulfed in flames. The wind at this point also picked up strength and began blowing from the east, pushing the fires back over the city. With water mains broken the brigade was unable to save many buildings. Pumping water from Clive Square they were able to stop the fires spreading South. Only a few buildings in the central Napier area survived. Some withstood the earthquake only to be gutted by fire. Trapped people had to be left to burn as people were unable to free them in time. By Wednesday morning the main fires were out but the ruins still smouldered for several days.

In Hastings, the fires were quickly brought under control.

The death toll might have been much higher had the Royal Navy ship HMS Veronica not been in port at the time. Within minutes of the shock the Veronica had sent radio messages asking for help. The sailors joined survivors to fight the fires, rescue trapped people and help give them medical treatment. The Veronica's radio was used to transmit news of the disaster to the outside world and to seek assistance. The crew from two cargo ships, the Northumberland and Taranaki, also joined the rescue works, while two cruisers, HMS Diomede and HMS Dunedin, were dispatched from Auckland that afternoon with food, tents, medicine, blankets, and a team of doctors and nurses. The cruisers sailed at high speed overnight, arrived on 4 February and provided valuable assistance in all areas until their departure on 11 February.

A group of prisoners working at Bluff Hill in Napier had four of their number buried in a landslip by the quake. The remaining prisoners dug them out, but two had been killed. The prisoners re-assembled without any attempt to escape and were locked up in the Napier Jail. In Havelock North, St Luke's church was destroyed just before a wedding was due to take place. The couple got married later in the day, but outdoors.

Within four days of the quake, cinemas around New Zealand offered news specials about the disaster.

Another casualty of the earthquake was the Napier trams. The tracks were twisted by the earthquake, and never restored.^[5]

New Zealand's first commercial air disaster occurred six days after the quake, when a Dominion Airlines Desoutter monoplane crashed near Wairoa. The small airline had been making three return trips a day between Hastings and Gisborne, carrying passengers and supplies. All three on board were killed.

The Napier Daily Telegraph had recently celebrated its diamond jubilee with an article describing Napier as "the Nice of the Pacific". The newspaper office was destroyed by the quake. The Hawke's Bay Herald offices in Hastings were also destroyed.

[edit] Rebuilding

The earthquake prompted a thorough review of New Zealand building codes, which were found to be totally inadequate. Many buildings built during the 1930s and 1940s are heavily reinforced, although more recent research has developed other strengthening techniques. To this day there are few buildings in Hawke's Bay taller than five stories, and as most of Napier's rebuilding took place in the 1930s when Art Deco was fashionable, Napier architecture is regarded today as being one of the finest examples of Art Deco in New Zealand. Hastings was also rebuilt with many Art Deco and Spanish Mission style buildings.

On the tenth anniversary of the earthquake, the New Zealand Listener reported that Napier had risen from the ashes like a phoenix. "Napier today is a far lovelier city than it was before", it quoted the 1931 principal of Napier Girls' High School as saying.