Evaluating and ranking Southeast Asia's exposure to explosive volcanic hazards

Abstract. Regional volcanic threat assessments provide a large-scale comparable vision of the posed by multiple volcanoes. They are useful for prioritising risk-mitigation actions and required local through international agencies, industries governments to prioritise where further study support could be focussed. Most regional studies have oversimplified hazards their associated impacts relying on concentric radii as proxies hazard footprints focussing only population exposure. We developed applied new approach that quantifies ranks exposure 40 high-threat volcanoes in Southeast Asia. For each our volcanoes, spatial extent, intensity appropriate, was probabilistically modelled four across three eruption scenarios, giving 697 080 individual plus 15 240 probabilistic outputs. These outputs were overlain with open-access datasets five categories using an open-source Python geographic information system (GIS) framework this (https://github.com/vharg/VolcGIS, last access: 5 April 2022). All – more than 6500 GeoTIFF files 70 independent estimates provided “Data availability” section user-friendly format. Calculated values used rank terms they pose surrounding communities. Results highlight island Java Indonesia has highest median hazards, Merapi consistently ranking highest-threat volcano. Hazard seasonality, result varying wind conditions affecting tephra dispersal, leads increased during peak rainy season (January, February) but dry (January April) Philippines. A key aim may been overlooked perhaps because not frequently or recently active potential affect large numbers people assets. It is intended replace official risk country volcano organisations. Rather, tools road map future multi-source possibility extend assessment other regions and/or towards impact loss.