Lava flow hazard map of Piton de la Fournaise volcano

Abstract. Piton de la Fournaise, situated on La Réunion island (France), is one of the most active hot spot basaltic shield volcanoes worldwide, experiencing at least two eruptions per year since establishment volcanological observatory in 1979. Eruptions are typically fissure-fed and form extensive lava flow fields. About 95 % some ? 250 historical events (since first confidently dated eruption 1708) have occurred inside an uninhabited horseshoe-shaped caldera (hereafter referred to as Enclos), which open ocean its eastern side. Rarely (12 times 18th century), fissures opened outside Enclos, where housing units, population centers, infrastructure risk. In such a situation, hazard maps useful way visualizing inundation probabilities over large areas. Here, we present up-to-date map for Fournaise based (i) vent distribution, (ii) recurrence times, (iii) statistics lengths, (iv) simulations paths using DOWNFLOW stochastic numerical model. The entire volcano highlights spatial distribution probability future invasion medium long term (years decades). It shows that probable location within Enclos (where there areas with up 12 probability), visited by more than 100 000 visitors every year. Outside reach 0.5 along rift zones. Although occurrence inhabited deemed be very low (< 0.1 %), it may underestimated our study only post-18th century records neglects older events. We also provide series computed multi-temporal (i.e., regularly updated) topography. remains broadly same time, changes noticed throughout analyzed periods due improved digital elevation model (DEM) resolution, high frequency constantly modifies topography, dimensional characteristics paths. presented here reliable trustworthy long-term assessment land use planning management. Specific short-term (e.g., responding volcanic crises) or considering cycles activity different event scenarios fed combinations temporally evolving superficial deep sources) required further affected – especially atypical but potentially extremely hazardous large-volume eruptions. At site, method supports need regular updates DEMs associated if effective keeping date mitigation risks.