Editorial: Tsunami advice must be improved

Aerial shots of SH1 south of Kaikoura. A devastating earthquake hit the Kaikoura region causing widespread damage including to roads out of the township. Photo / Mike Scott

Ten months after the destructive February 2011 earthquake, an independent review of the Ministry of Civil Defence and Emergency Management's response was undertaken.

The assessment concluded that by and large the ministry handled the disaster well, but identified areas where improvement was needed.

The 7.8 magnitude Kaikoura earthquake early on Monday morning has presented civil defence managers with their biggest challenge since the Christchurch disasters. When the emergency phase passes the ministry needs once more to review its performance.

The country is extremely fortunate that Monday's severe upheaval claimed only two lives. The communities in the affected areas were helped by the extraordinary response that we are more accustomed to seeing in conflict zones.

For the first time in the sequence of tremors which began with Darfield in September 2010, the threat of a tsunami has been added to the risks of slips, landslides and building collapses.

There has been valid criticism that information about the tsunami risks was confused. Different civil defence jurisdictions responded unevenly. Sirens sounded in Petone, at the top of Wellington Harbour, but not at Lyall Bay which is open to Cook Strait and where tsunami activity occurred.

At Brighton, Christchurch's eastern beach suburb, sirens did not sound until about 2am, an hour after the national civil defence website advised coastal residents to get to higher ground.

Even then, congestion and roads still bearing the scars of the last Canterbury quakes slowed the exodus.

Further south, some South Dunedin residents complained they too were left confused whether to leave their low-lying suburb. Many sought higher ground after the national warning at 1am. At 3am, the Dunedin regional agency issued an alert saying protection from sand dunes meant the suburb was not at risk.

Throughout the early morning hours, warnings were being repeated that 3m to 5m waves could occur. In the end the coast was spared but the information provided was erratic and uneven.

In the case of Brighton, residents were ready to leave but found it hard to move. For people in Lyall Bay and Rongotai, there was no blasting noise to rouse them from their slumber.

The dramatic physical events which have left the country and people's psyches scarred require clear and well-understood responses to protect lives. There can be no room for confusion or second-guessing. The emergence from the Kaikoura earthquake of a real tsunami risk adds to the urgency of resolving this uncertainty quickly. In the past tsunami exercises have been met with shrugs of indifference. That is no longer an acceptable response. Equally the advice that an earthquake is in itself the tsunami warning falls short of the best that a community can expect.

New Zealand is experiencing an intense time of earthquakes. It is a responsibility of the civil defence authorities to ensure that everyone understands the tsunami warning system, and that it works the same for all.