Friday 7 April 2017

Tsunami alert review recommends changes

Community response plans will be developed with coastal communities in Christchurch and Banks Peninsula as a result of a review of the tsunami alert that followed the 14 November 2016 Kaikoura earthquake.

The review was conducted by Christchurch City Council at Mayor Lianne Dalziel’s request to address issues raised by elected members and residents in coastal communities about the activation of the tsunami sirens and the evacuation that followed the quake.

The findings of the review are released today, along with 48 recommendations on how to address issues.

“The biggest lesson is if an earthquake is ‘long or strong, get gone'. Don’t wait for the sirens,” Lianne Dalziel says

“But it’s important that the approximate 20,000 people living in coastal evacuation zones for a local source tsunami know when and how to evacuate and where to go once they do evacuate. Everyone getting in a car and driving is not an effective way to evacuate ahead of a local source tsunami.

“There was considerable confusion in the wake of this extraordinarily complex earthquake – in relation to the threat of a tsunami being identified by the Ministry of Civil Defence and Emergency Management (MCDEM), whether there was a need to evacuate and then with the evacuation itself. The community was getting mixed messages,” Mayor Dalziel says.

“It is so important whenever we have an emergency situation like the tsunami alert and evacuation, that we review what worked, what didn’t and then make the required improvements to address the issues raised. The community needs to have the confidence to know what to do in times of emergency.”

The review’s focus was to determine why on the night of the tsunami alert, the messaging was inconsistent between agencies, how the evacuation decision-making process worked, how evacuation of coastal communities could be better coordinated, what information communities require and how they can access that information.

The review says that, after the earthquake, Christchurch Civil Defence Emergency Management (CDEM) tried to gather as much information as quickly as possible regarding the tsunami threat specific to Christchurch and whether residents needed to be evacuated.

The initial tsunami warnings from MCDEM did not refer to a threat to land which is the trigger for an evacuation of coastal communities under the Ministry’s guidelines.

The first message from MCDEM to local groups advising the threat to land was at 2.01am. It followed this up with a telephone call to the regional Canterbury Civil Defence directing that an evacuation of Christchurch coastal residents was necessary.

The 45 tsunami sirens installed along the Christchurch coastline from Brooklands to Taylors Mistake were sounded within 10 minutes after the national warning was issued.

Some residents evacuated before the sirens, but most relied on the sirens. MCDEM advises against the use of sirens for local source tsunami events. Its advice is that if an earthquake is long or strong then residents should evacuate without waiting for the sirens.

One of the priorities is for Christchurch CDEM to work with residents and other agencies on co-creating a coastal response plan specific to each community. Residents interviewed for the review said they wanted to and should be involved in the creation of these plans.

The plans would cover the different responses required for local, regional and distant source tsunamis as well as other risks such as severe weather, pandemic and fire. Once agreed between various agencies and residents, the community response plan would be made publicly available.

The review also highlighted the need for simple, easily accessible coastal evacuation maps. There was a coastal evacuation map on the Council’s website on 14 November 2016, but this was for distant source tsunamis and not local or regional source tsunamis. Tsunami evacuation maps were also available on the Canterbury Maps portal where data from territorial authorities is shared, but again none was specific for local source tsunamis.

Residents were not immediately directed to the map or provided with a procedure to follow to evacuate. Many residents were unclear as to whether they needed to evacuate or not and where the evacuation zones were. The review says there is a need for clear, concise, consistent messaging across all forms of media including letterbox drops, social media, internet and information on notice boards in communities. There is a recommendation to develop this information with the community.

Read the tsunami alert review online.

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