Little choice on Chathams but to live with tsunami risk

Pat Tuanui at the only structure that survived the 1868 tsunami - a fireplace. Picture / Richard Robinson

A solitary stone fireplace in a remote corner of the Chatham Islands is all that remains from New Zealand's most recent fatal tsunami.

When the big wave hit soon after 1am on August 15, 1868, the fireplace was in one of two European-style houses in the thriving village of Tupuangi.

An hour later, the entire village, apart from the fireplace, was destroyed.

Although its residents escaped to the nearby hill of Maunganui, a man named Makare was not so lucky about 7km to the west. After the first wave struck, he swam out to save a boat belonging to his employer, Captain Anderson, but was carried away on a second wave and drowned.

Today a single family, Pat and Jo Tuanui and their two children, live on the large cattle station that includes the site of the village, where the sea has eaten into the coastline by about 30m in the past 10 years.

The Tuanuis' home, about 2km south, is enclosed by sandhills - several hundred metres further back from the sea than the site of Tupuangi, but still possibly vulnerable to a giant wave.

But Mr Tuanui, who is descended from relatives of the Taranaki Maori who lived in the village, is philosophical. He loves the land and is willing to take his chances.

Most people on the Chathams, exposed to all sides of the Pacific, have no option but to adopt the same attitude. Much of their land is low-lying lakes and peat bogs, reaching a high point of only 287m in the uninhabited south of the main island.

Ruth Raumoa-Brown, who had to run from another tsunami at Taupeka on the north coast as a child of 10 in 1947, said last week: "My thoughts are that if you're going to go, regardless of what you are, if your time's up that's it. I can remember just standing there watching the things out at sea and the water being taken out of the harbour and around the beach, then the water coming in. It was just one big wall of water," she said.

"Mum was pulling out the stock-whip and calling to us to run. She was making us go up the hill up towards the woolshed.

"Mum must have known what it was. She made us move. I think she was pulling Jimmy [a younger brother]."

Her family's house withstood the wave but was uninhabitable afterwards.

The family lived in a woolshed until they built a new house out of ponga trees a year or two later.

Mrs Raumoa-Brown's mother, Polly Brown, was the oldest person on the islands until she died last month, aged 89. She had lived through three tsunamis, in 1924 and 1960 as well as in 1947.

Gaye Downes, tsunami team leader at the Institute of Geological and Nuclear Sciences in Lower Hutt, said the waves reached 6m at the Chathams, possibly due to a local underwater landslide, in 1924, and 10m near Gisborne on the mainland in 1947.

The 1960 tsunami was triggered by a magnitude 9.5 earthquake in southern Chile, the biggest quake recorded on Earth since records began. It caused waves 3-4m high both on the Chathams and on Banks Peninsula near Christchurch.

Ms Downes said New Zealand had a lucky escape that year, because the orientation of the fault line where the quake struck carried the main force of the tsunami northwest to Hawaii, where 61 people died, and Japan, where it killed 122 people.

Her institute has calculated that, if a quake of the same size hit the area round the Peru-Chile border that triggered the 1868 wave, both the Chathams and mainland New Zealand would be directly in the path of a tsunami.

She said Japan had built walls up to 15m high to protect parts of its coast from tsunamis, but New Zealand relied mainly on a good warning system.

"It's not only the first few waves," she warned. "We are also saying that waves bounced off some of the Pacific islands may head to New Zealand as well. Once these tsunamis start, they sometimes bounce round the Pacific for at least three days."

NZ's biggest tsunamis
* Aug 1868 6m, Chatham Islands
* May 1877 3.7m, Port Chalmers
* July 1924 6m, Chatham Islands
* Feb 1931 15.3m, Hawkes Bay
* Mar 1947 10m, Gisborne
* May 1947 6m, Gisborne
* May 1960 3.5m, Banks Peninsula
Source: Hicks & Campbell (eds), Awesome Forces, Te Papa Press, 1998.