Volcanic eruptions can severely disrupt and/or destroy rural transport networks, potentially impacting evacuations, and isolating communities for days, weeks or months. Isolation can prevent communities from accessing essential services such as food, medical care, fuel, and social networks. Disruption of rural transport networks can be detrimental to primary industries, affecting production and preventing the transport of produce to markets, impacting regional and national economies.

Māori, the Indigenous People of Aotearoa (New Zealand) have witnessed volcanic activity for hundreds of years. Marae are physical, spiritual, and cultural centres of Māori identity. Marae are also vital in a disaster response to provide manaaki to their communities and serve as locally-led welfare and coordination centres. However, volcanic eruptions can affect the functioning of marae and their safety through direct damage or indirect impacts such as loss of critical infrastructure.

Taranaki Mounga is an ancestor to Māori and classified by volcanologists as a dormant stratovolcano in Aotearoa’s North Island with a probability of eruption in the next 50 years of between 33% and 42%. Taranaki’s marae are at the heart of some rural communities, as are primary industries, particularly dairy farming. Primary industries employ around 16% the region’s workforce and contribute nearly $1 billion to Aotearoa’s Gross Domestic Product (GDP) annually.

Previous work has assessed volcanic impact to Taranaki infrastructure such as water and electricity. However, no work has analysed volcanic impact to rural transport and how this would affect rural communities. This thesis aims to understand impacts to rural communities by assessing loss of service to Taranaki rural transport. Impacts to rural communities will be assessed by modelling the ability of marae and farms to access regional exit routes and rural support services. This will be undertaken using an existing suite of nine Taranaki Mounga eruption scenarios developed by Weir et al. (2022), with a focus on a large scenario (L1).

This thesis found the most destructive eruption scenarios to be L2 which rendered 40% of roads unusable and L1 which rendered 45% of bridges unusable. Across all scenarios, State Highway 3 between Stratford and Inglewood, State Highway 43 near Stratford, and State Highway 45 between Hāwera and Manaia were frequently untraversable with few alternative routes available. This means that an eruption could prevent travel between north and south Taranaki on both sides of the mounga. When considering ashfall, roads and bridges in and west of Stratford most frequently lost all service. When considering lahars, the most frequent loss of service was in and near Kaponga.

The most challenging situation for many rural communities accessing support services would be isolation of New Plymouth, which occurs in scenario L1. This would put severe strain on fuel supplies in Taranaki and force vets to serve more clients. At least one Fonterra factory was affected in five eruption scenarios. Reduced operation of any site would impact dairy farm production and income.

By the end of the L1 scenario, 27% of marae and 48% of farms became isolated. This scenario, particularly in north and east Taranaki, would prevent many rural communities from accessing support services. Given the number of bridges affected in L1, and the impact observed from Cyclone Gabrielle, these communities could be isolated for weeks or months. In the L1 scenario, by phase 5d, any evacuations would need to use the southern regional exit route. Access to New Plymouth port and airport was not possible for 90% of marae and 85% of farms by road in this scenario. Therefore, these areas would require aid from elsewhere. Isolation of and impact to such a wide area could have a significant impact on the wellbeing of people, livestock health, agricultural production, and Aotearoa’s economy. Future research should model the recovery of Taranaki rural transport and communities to assess the duration of potential isolation and explore the cultural impact of evacuations, isolation, and displacement from marae to support iwi- and hapū-led planning.