Understanding ashfall impacts and recovery from the 15 January 2022 eruption of Hunga Tonga-Hunga Ha’apai volcano, Kingdom of Tonga

The 15 January 2022 Hunga Tonga-Hunga Ha’apai eruption generated a tsunami and ashfall that had widespread impacts to human health, buildings, agriculture, and infrastructure across the Kingdom of Tonga (population ~108,000). Currently, there is limited data on impacts and recovery from ashfall in the South Pacific.

To address this gap, fieldwork was conducted on the island of Tongatapu in June and August 2023, focussing on four main areas:

1)    the collection of primary ashfall impact data;

2)    what are Tongan partner agencies’ interests?

3)    how can we collaborate with local existing projects and research directions? and

4)    how can we better collaborate on science support?

Interviews were conducted with Tongan agencies, including the: National Emergency Management Office; Ministry for Agriculture, Food, Forests, and Fisheries; Ministry of Infrastructure; Ministry of Health; Tonga Water Board; and Tonga Power Ltd. Additionally, a stakeholder workshop was conducted focussing on knowledge transfer and planning preparedness resources.

The main lessons identified related to: arrangements for rapid ash hazard characterisation to inform the emergency management response; the requirements for ongoing cleaning of remobilised ash, particularly from electrical transformers and stormwater systems; improving awareness of cascading impacts from areas affected by both ashfall and tsunami; and the need for Tonga-specific ashfall preparedness and response resources. This presentation highlights the complexities in long-term recovery from ashfall in Tonga, and lessons learned for the wider South Pacific. We discuss the opportunity for continued science collaboration and fostering knowledge exchange mechanisms in future research.