In 2009/2010 Environment Canterbury commissioned the National Institute of Water and Atmospheric Research (NIWA) to model inundation (flooding) along parts of the Canterbury coast from a “worst-case” South American tsunami.
The project modelled how high above normal sea level a “worst case” distant-source tsunami would be at the coast for the whole of Canterbury. This used a scenario based on the 1868 South American tsunami, which flooded a lot of land in Canterbury, and is one of the largest distant-source tsunamis we could expect.
The project then modelled how much land would be flooded from this sea level at the coast. Flooding on land was only modelled for areas where good topographic (land height) information was available. These areas were:
Christchurch City was not included in this modelling because distant-source tsunami models were already available for the area, and these had been used by Christchurch City Council and the New Zealand Police to determine coastal evacuation zones for Christchurch City in 2007. The 2009/2010 NIWA modelling concentrated on areas where there was no previous modelling available.
Download the report here (4.75 MB)
Following the 22 February 2011 earthquake Environment Canterbury, in collaboration with Christchurch City Council and Waimakariri District Council, decided to remodel the 1868 South American tsunami scenario for Kaiapoi/Kairaki/Pines Beach, and to extend the modelling down the Christchurch coast to Taylors Mistake. This was done to see if changes were needed to the 2007 coastal evacuation plan for Christchurch due to earthquake-related subsidence in Christchurch, and to assist Waimakariri District Council to determine distant-source tsunami evacuation zones for Kaiapoi/Kairaki/Pines Beach using the most up-to-date land heights.
Download the report here (2.35 MB)
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