An extreme natural event in New Zealand – Case study Napier Earthquake, 1931 An extreme natural event in New Zealand – Case study

Where is the Hawkes Bay? The Hawkes Bay is located on a zone of seismic activity, running down the lower East coast of the North Island. The Pacific plate is being subducted 23km beneath Napier and continues to a depth of 80km beneath Mt Ruapehu. Riding over it is the Indo-Australian plate forming the ranges of the Hawkes Bay. The plates are colliding at a rate of 55mm per year.

Location of the Hawkes Bay.

Tuesday 3rd February, 1931 On the morning of Tuesday 3rd February, 1931, the residents of Napier were going about their every day activities. The people of Napier had always known about earthquakes, but nothing had prepared them for what was to happen.

Where was the earthquake centred? The earthquake sent seismic waves in all directions traveling at 6km per second. Its epicenter was 30km north west of Napier and its focus was very shallow – 16km below the surface.

The first shakes …… The face of the city changed on a hot summers morning. At approximately 10:47am the first quake hit measuring 7.0 on the Richter scale, then 30 seconds later the next quake hit measuring 7.8 lasting two and a half minutes.

What happened? The first shock caused the cliff face of the distinctive Bluff Hill to collapse down upon the road, buildings swayed and chimneys collapsed to the ground. The second shock shortly after was a jolting upward motion which caused 10 acres of Napier’s buildings to collapse into rubble, killing many of those people who had earlier run out into the street for safety.

Effects on buildings …..

Effect on social and economic activities On top of Napier hill the nurse’s home at the public hospital crumbled away killing most of the off duty staff. Great gaps appeared in the road swallowing cars.

Effect on the land….. Tramlines buckled as the land around Napier rose two metres lifting land 20km long and 5 km wide. The Ahuriri Lagoon, where residents sailed their yachts, was completely drained leaving a new large area of land.

Before and after the earthquake

And then there was fire…. The buildings that had not been damaged by the earthquake were soon to be destroyed by fire when a blaze began in a chemist shop in Hastings Street. Fanned by the wind the flames soon engulfed the town and with the water mains broken, members of the fire brigade had to stand helplessly aside, unable to save what little remained. The ruins smouldered for days.

The economic costs of the EQ A total of $300 million of damage was caused as buildings collapsed, roads destroyed and businesses damaged. More than 200 businesses were damaged.

Help was needed. With roads, railway lines, power supply and telephone links cut there seemed little hope of contacting the outside world for help. Fortunately, the Royal Navy HMS Veronica was in port and alerted the rest of the country by radio while her crew helped rescue victims trapped in the debris.

Two cargo ships arrived to aid the survivors as did two cruisers, which sailed down from Auckland complete with food, tents, medicine, blankets and a team of doctors and nurses. The cruisers arrived on the 4th February and provided valuable assistance in all areas until their departure on the 11th February.

Aftershocks continued for ten days following the quake and to may people these proved as frightening as the major tremors. Temporary camps were set up on the Marine Parade beachfront and at the racecourse until people were able to repair or rebuild their homes. Many children were sent to relatives or friends in other parts of New Zealand. In the aftermath, 256 lives were lost.

Napier in ruins..

In the two months after the quake there were 674 aftershocks. An earthquake relief fund was opened by the Prime Minister and eventually reached $800000. The government gave $3000000 to the people of Napier in the form of low interest loans. Architects banded together for the next five years to rebuild the town in an Art Deco style.

Napier Now The effect of this was a city that is now famous for its architecture