GIS-based mass evacuation planning for the Auckland volcanic field

Abstract

Auckland, New Zealand's largest city and home to roughly 1/3 of the country's population, is situated atop an active monogenetic volcanic field. The impact of the next Auckland Volcanic Field (AVF) eruption will be based largely upon the eruptive size and vent location. The aim of this thesis was to analyse the geographic distribution of population and infrastructure throughout the AVF and how it impacts mass evacuation planning considerations. This was achieved by conducting geospatial analysis using ArcGIS and transportation modelling with TransCAD. Non-specific analyses, for any location within the AVF, were used to determine the range and spatial distribution of population evacuation demand. Select critical infrastructure sites (e.g. bridges, hospitals, fire stations, water treatment plants, etc.) were assessed to determine their vulnerability. Sites where vulnerabilities overlapped were given special consideration. Intriguingly, low-mobility populations generally have better than average access to public transportation resources. Finally, evacuation difficulty was assessed at the micro-scale (neighbourhoods), by way of population to exit capacity ratios, and the macro-scale with volume over capacity ratios and clearance time estimates. Micro-scale vulnerability was found to be highly correlated to diurnal population movements and neighbourhood boundary types. Macro-scale vulnerability was far more contingent upon the destination of evacuees, with favourable results for intra as opposed to inter-regional evacuations.