Communication breakdown behind post-earthquake tsunami confusion

6:30 pm on 7 April 2017

A report into how authorities handled the tsunami alert after the 14 November Kaikōura earthquake has revealed a communication breakdown between the Christchurch City Council and Civil Defence.

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A roadside tsunami warning on 14 November 2016. Photo: RNZ / Tracy Neal

After the 12.02am earthquake hit, the Ministry of Civil Defence issued a tsunami alert at 1am.

However, Christchurch tsunami sirens did not sound until after 2am, leaving many residents living in the seaside settlement of New Brighton confused about whether they were required to evacuate.

After the reponse was criticised, Christchurch Mayor Lianne Dalziel requested a review in December.

In the report, released today, Ms Dalziel said the Ministry of Civil Defence put a different notice on their website to the information sent to local civil defence teams.

"Our local team responded entirely appropriately to this instruction," she said in an email included in the report.

Christchurch mayor Lianne Dalziel

Christchurch Mayor Lianne Dalziel said a coastal plan would now be developed for seaside communities. Photo: RNZ / Conan Young

Ms Dalziel said local civil defence teams took advice from Environment Canterbury, who said an evacuation was not "warranted".

In the report, the Ministry of Civil Defence denied there was a communication breakdown.

It said the tsunami sirens were an "inappropriate" way to warn people about an incoming threat and could increase the risk to the public.

"Signal-only sirens provide an ambiguous message, and are particularly difficult to understand for visitors and new migrants. They provide no information on the nature of the threat or the correct [actions] to take," it said.

Ms Dalziel said a coastal response plan would be developed for seaside communities. It would cover different disaster scenarios.

Read the full report here.