Tsunami system gains first siren

Western Bay council officers Barry Low (left) and Alan Pearce with one of the new sirens. Picture / Alan Gibson

The first siren for a tsunami warning system in the Western Bay of Plenty has been installed at Mt Maunganui.

The siren at Baypark Stadium is one of 11 that will cover the coast from Waihi Beach to Mt Maunganui, including Papamoa, Maketu and Pukehina.

Architect of the system, the Western Bay of Plenty District Council, hopes it will be working by Christmas.

Barry Low, the council's manager of emergency management, said having the first siren ready was a milestone.

Planning for the warning system began several years ago, but took on urgency after the Boxing Day tsunami because of concern about the danger posed in the Bay's heavily populated, low-lying coastal strip.

"We're wide open to the Pacific," said Mr Low.

Computer models show a tsunami between 5m and 10m high would cut state highways and flood areas as far inland as Te Puke.

Matakana Island, Mt Maunganui and Pukehina would probably end up under water.

The new system will use existing fire station sirens for the most part. The siren at Baypark is one of only two new ones needed, keeping the engineering costs of the project to $30,000.

All the sirens will sound any time an alert is generated by the Pacific Tsunami Warning Centre in Hawaii.

They will broadcast a distinct sound, indicating to people that they should move to higher ground.

The sirens will probably be given a test run.

As part of the system, a traffic management plan is being drawn up and the council plans to launch a public awareness campaign.

Council emergency management training officer Alan Pearce said changing people's attitudes about the threat of tsunamis would be one of the biggest hurdles.

"We're still a long way from people saying it could happen here."

But he said recent research showed evidence of powerful waves, triggered by earthquakes, hitting New Zealand in the past.

Tsunami damage had been detected 7km up the Wairoa River and seabed deposits had been found in other areas.

He and Mr Low said more was being learned about tsunamis all the time and the research justified the need for a warning system.

Other councils such as Napier and Northland are looking to follow Western Bay of Plenty's lead.

The system will provide warning of tsunamis that come from far away, but will not protect against those generated nearer to New Zealand.

Anything less than four hours away gave authorities little time to co-ordinate a response, Mr Low said. Less than an hour, "There's no chance to warn".