Tsunami evacuation model for Sumner, Christchurch, New Zealand

Sumner, a coastal suburb located to the south-east of Christchurch, New Zealand, is highly exposed to a number of tsunami hazards. In tsunami mitigation plans, evacuation plays a crucial role in saving human lives, especially for communities located in low-lying coastal areas. The aim of this thesis is to enhance the methodological basis for development of tsunami evacuation plans in Sumner. To achieve this, a numerical simulation output of far-field tsunami impacts in Sumner was used to establish the maximum likely inundation extent and flow depth. This, together with population census data and daily activity patterns specified for the study area, established the spatio-temporal basis for characterising population exposure to the tsunamic hazard. A geospatial evacuation analysis method (Least Cost Path Distance), augmented with variable population exposure and distributed travel speeds, was used to characterise spatial variation in evacuation times and the corresponding numbers of evacuees and vehicles. Three ‘extreme’ end-member scenarios were utilised to address possible evacuation methods; all pedestrians evacuated to 20 metres elevation, all pedestrians to bus stops for evacuation using public transport, and all people evacuated using private vehicles. This thesis has made a methodological contribution to tsunami evacuation simulation by characterising variable spatio-temporal population exposure, and incorporating terrain properties into population and vehicle movements. The methods are equally applicable to other locations, to other hazards, and for both pre- and post-disaster evacuation analyses