Informing the development of tsunami vertical evacuation strategies in New Zealand : a thesis presented in fulfilment of the requirements for the degree of Doctor of Philosophy in Emergency Management at Massey University, Wellington, New Zealand
Tsunami education and evacuation planning promote evacuation to high ground in the event of
tsunami. In some low-lying coastal areas, the distance to safety on high ground or inland of the
hazard zone may exceed the travel distance possible in the time before wave arrival. This is a
particular problem in local-source tsunami with arrival times of less than one hour. Vertical evacuation
provides alternative refuge within the inundation zone. Buildings, towers or berms can
provide refuge at elevations above the tsunami flow depth, but must be designed to be effective in
the maximum credible tsunami. The potential benefits and costs of vertical evacuation buildings
were demonstrated during the 2011 Great East Japan earthquake and tsunami, when thousands of
people took refuge in such structures.
The aim of this thesis is to enhance the current theoretical and methodological basis for development
of vertical evacuation strategies in New Zealand. To achieve this aim, numerical simulation
of local-source tsunami is conducted at Napier, Hawke’s Bay, New Zealand, to establish the maximum
credible inundation extent, flow depth and arrival times. Interview data describe the use of
vertical evacuation in the 2011 Great East Japan tsunami, and surveys are used to investigate intended
evacuation behaviour in a local-source tsunami. Finally, an existing geo-spatial evacuation
analysis method, augmented with temporally-variable exposure and distributed travel speeds, is
used to assess pedestrian evacuation potential in local-source tsunami. The method is demonstrated
in an assessment of the need for vertical evacuation in Napier.
The outputs of the four stages of research enhance the theoretical basis for planning evacuations
in local-source tsunami, extends Geographic Information System-based evacuation modelling
methods, and provides empirical advances in tsunami hazard and evacuation planning at Napier.
The proposed methodology is applicable to other locations, thus contributes to tsunami risk reduction
in New Zealand and internationally.