Download the report here - Updated inundation modelling in Canterbury from a South American tsunami (3.9 MB).
View the map journal app and interactive GIS map at Canterbury Maps.
Our latest report re-maps potential flooding along parts of the Canterbury coast from a large distant-source tsunami created off the coast of South America. The scenario used in this report is a tsunami created by a magnitude ~9.5 earthquake off the Northern Chile/Southern Peru coast - this is larger than the scenario used in previous distant-source tsunami reports (approximately magnitude 9.1). This is because scientists now think that larger distant-source tsunamis can affect us than previously thought. This report replaces the previous NIWA reports below.
A distant-source tsunami generated off the South American coast from a magnitude ~9.5 earthquake has a return period of around 2500 years for most of the Canterbury coast. This is the return period recommended for evacuation planning. This scenario is not intended to be used for land use planning, because land use planning generally uses shorter return periods of up to 500 years, and the potential flooding from a 500 year return period tsunami could be less than this scenario.
The report shows that for most areas in Canterbury there is not much difference in the areas that may be flooded by a distant-source tsunami created by a magnitude 9.5 earthquake, compared with past reports that used a magnitude 9.1 earthquake scenario. However, in some areas the flooding is deeper. This confirms, rather than changes, existing evacuation areas for most places in Canterbury.
These reports have been replaced by the updated 2014 report (above) so are now out of date, but they are still available for download here.
Download the report here - Modelling coastal inundation in Canterbury from a South American tsunami report (2011) (4.75 MB)
In this report NIWA mapped potential flooding along parts of the Canterbury coast from a tsunami similar to the 1868 South American tsunami, created by a magnitude 9.1 earthquake off the coast of Peru, which is one of the largest distant-source tsunamis we could expect. The 1868 tsunami flooded a lot of land in Canterbury, but these areas are mostly not well recorded. Also, the tsunami arrived near low tide, so the flooding was not as bad as it could have been had it arrived at high tide.
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 2011 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 2011 NIWA modelling concentrated on areas where there was no previous modelling available.
Download the report here - Modelling coastal inundation in Christchurch and Kaiapoi from a South American tsunami using topography from after the 2011 February earthquake report (2012) (2.35 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 (used for the above 2011 report) 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 - Tsunami inundation modelling for Kaikoura and North Canterbury report (2013) (1 MB)
Tsunami flooding from a distant-source tsunami similar to the 1868 South American tsunami was modelled for the Kaikoura coast from Oaro to Kekerengu in 2013. This used high resolution topographic (land height) data for the Kaikoura coast collected by Environment Canterbury in 2012, which wasn't available when the tsunami modelling for the rest of the Canterbury coast was done in 2011.
This report only looks at a distant-source tsunami from across the Pacific Ocean. Kaikoura is also vulnerable to local-source tsunamis created close to shore - see our Tsunami information for Kaikoura page for more information.
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