Lava flow impacts on the built environment: Insights from a new global dataset

The recent destruction of thousands of homes by lava flows from Cumbre Vieja, La Palma, Spain and Nyiragongo volcano, Democratic Republic of Congo, serves as a reminder of the devastating impact that lava flows can have on communities living in volcanically active regions. Damage to buildings and infrastructure in particular can have widespread and long-lasting effects on rehabilitation and livelihoods. Our understanding of how lava flows interact with buildings is limited and based upon sparse empirical data. Often a binary impact is assumed (lava flows destroy buildings), although previous events have shown this to be an oversimplification. Empirical damage data collected after past events can provide an evidence base from which to better understand lava flow impacts across a range of building types, environments and eruption styles, as well as temporal and spatial trends. However, information on lava flow impacts is scattered across literature, reports and maps; no comprehensive dataset of lava flow impacts exists. In this study, we review, compile and standardise lava flow impact information in published literature to create the first comprehensive global dataset of lava flow events with impacts on the built environment. We found that since the first recorded event between 5494 year B.P. and 5387 year B.P., lava flows from at least 127 eruptions impacted buildings or infrastructure, with the most (34%; n = 43) located in Europe. There are almost six lava flow impact events per decade, with 57 events occurring in the past 100 years (or 39 events without infrastructure-only impacts). This greatly expands on the past estimate of lava flow impact frequency of two events per decade. Impacts from lava flows are documented in less than 10% of recorded lava flows globally, with this remaining constant since ∼1800 CE; prior to 1800 CE, impacts were recorded much more variably representing between 0 and 35% of lava flows in any 10 year time bin. The most destructive recorded events were the 1669 CE lava flows at Etna volcano, Italy, which destroyed up to 12 villages and part of the city of Catania, and the 2002 CE lava flows at Nyiragongo volcano, Democratic Republic of Congo which destroyed at least 4,500 buildings. We found that few studies in the dataset report building typology, damage severity, hazard intensity, or damage at the structure-level scale, limiting our ability to assess past building-lava interactions. Future collection of structure-level hazard and impact data can be used to inform models to forecast future impacts, support lava flow risk assessments and develop potential mitigation measures.