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Geographic Area 

The report covers Porirua and Kapiti Coast Districts in the Wellington Region. 

Summary 

This report presents the results of tsunami inundation modelling and the delineation of evacuation zones for the Porirua and Kapiti Coast areas. The study was commissioned to support emergency planning and public safety by identifying areas at risk from tsunami inundation. Using hydrodynamic modelling techniques, the authors simulated tsunami wave behaviour and potential flooding scenarios based on a range of earthquake sources. These included local, regional, and distant events that could generate tsunami waves affecting the Wellington Region. 
 
The modelling considered various factors such as wave height, arrival time, and extent of inland flooding. The results showed that low-lying coastal areas, estuaries, and river mouths are particularly vulnerable to tsunami inundation. The study identified three evacuation zones: red, orange, and yellow. The red zone represents areas most likely to be affected by frequent, smaller tsunamis. The orange zone includes areas that could be inundated by moderate-sized events, while the yellow zone covers areas at risk from the largest, rare tsunamis. 
 
These zones were mapped using geographic information systems (GIS) and are intended to guide evacuation planning and public awareness. The report emphasizes the importance of timely evacuation and community preparedness, especially in areas where tsunami waves could arrive within minutes of a local earthquake. It also highlights the need for ongoing review and updates to evacuation zones as new data and modelling techniques become available. 
 
Overall, the report provides a scientific basis for emergency management decisions and contributes to reducing the risk posed by tsunamis in the Porirua and Kapiti Coast communities.