Building damage from thick tephra fall can have a substantial impact on exposed communities close to erupting volcanoes. However, historical records of the impact of thick tephra fall on buildings are limited. Moreover in the tropical, southwest Pacific there are few documented accounts of the impacts of multi-phase and basaltic tephra falls to traditional thatch buildings. In 2017/18 a multi- phase, explosive eruption from Manaro Voui volcano, Ambae Island, Vanuatu damaged local buildings. This thesis presents a comprehensive record of the impact of the March/April and July 2018 tephra falls from Manaro Voui to address current gaps in the literature regarding traditional building damage from tephra fall.

Impacts of tephra fall on buildings on Ambae island were recorded during two field visits in April and August 2018. Field and photographic surveys were used to record damage to 589 buildings from the March/April and July 2018 tephra falls from Manaro Voui. The construction characteristics of each building were described from observations in the field.

The damage buildings sustained from tephra fall was described according to a ‘damage state’ framework, customised for this study. Complete collapse of traditional buildings was observed from ~40 mm of tephra deposition. However, some traditional buildings sustained no damage in areas with 200 mm of tephra deposition. The variation in building damage, even at similar tephra loadings, appears to have been influenced by a wide range of pre-eruption building conditions, including the age of materials and termite damage to wooden structural members or the application of diverse mitigation methods.

Several rapidly implemented mitigation methods were observed that reduced building damage and maintained building habitability in areas exposed to tephra fall. The most effective method for minimising building damage appeared to be the installation of tarpaulins on thatch roofs, which aided tephra shedding thereby reducing loading. Preventing tephra ingress in buildings (to maintain adequate habitability) was challenging due to the highly-ventilated nature of buildings in tropical climates, exacerbated by the frequent ash falls and remobilisation of tephra by passing vehicles, people and wind.

This study presents the first empirical dataset for traditional Pacific Island buildings damaged by tephra fall. These results contribute towards the otherwise limited global empirical data available for tephra fall building damage, improving the current evidence base in forecasting future volcanic impacts.