Lava flow crises in inhabited areas part I: lessons learned and research gaps related to effusive, basaltic eruptions

Lava flows have threatened and/or inundated inhabited areas and/or their supporting networks 38 times at 12 volcanoes in the past 70 years. A systematic evaluation of these events has not been undertaken, making it hard to compare eruptions, create lava flow vulnerability models to support impact assessments, and deduce best practices for managing lava flow crises. In this paper, we summarise all 38 basaltic lava flow crises and conduct a gap analysis by evaluating published literature. Eleven data types that could support enhanced physical impact studies and/or research on the societal effects of lava flows were identified. Four of the data types (preparation actions and narrative, eruption narrative, response narrative, and evacuation data) have been well-documented (i.e. documented in at least half the eruptions). Communication approaches and recovery narratives have been included in at least a quarter of the studied eruptions, and their documentation in the literature is increasing with time. Five data types (lava flow attribute data, detailed physical impact data, and information on lava flow hazard modelling, community reactions, and applications of learnings) have only been documented a handful of times each. We suggest that standardisation of data collection and data storage could increase the frequency with which these data types are documented. Finally, we use the case studies to extract lessons about how community understanding of volcanic hazards influences community resilience and how lava flow modelling can inform planning. We also describe lessons relating to evacuation processes, mitigation methods, and recovery.