Volcanic crisis management supported by near real-time lava flow hazard assessment at Piton de la Fournaise, La Réunion

Abstract

Since 1979, Piton de la Fournaise (La Réunion) has erupted on average two times per year, with 95 % of these eruptions occurring within an uninhabited caldera. However, lava flows have occasionally impacted populated regions on the island, as in 1977 and 1986. Since 2014, an integrated satellite data–driven multinational response to effusive crises has been developed to rapidly assess lava inundation area and flow runout distance. In 2018, this protocol was implemented as a standalone software to provide a lava flow hazard map showing the probability of flow coverage and runouts as a function of discharge rate. Since 2019, the produced short-term hazard map is shared with local civil protection in the first few hours following the start of an eruption to aid in mitigation actions. Multiple exchanges between scientists, the observatory, and civil protection has improved the delivered hazard map, ensuring a common understanding, a product which is of use and usable, and helping to build effective mitigation strategies at Piton de la Fournaise. In this work we illustrate this effective near real-time protocol with case studies and document how the produced short-term hazard map has been tailored to meet the needs of civil protection.

Infrared spectroscopy of volcanoes: from laboratory to orbital scale

“…These are important considerations for hazard planning and risk mitigation, and so, the accurate retrieval of accurate emissivity for different lithologies at varying temperatures is essential. This has already been performed at Piton de la Fournaise Volcano, Réunion (Harris et al, 2019;Chevrel et al, 2022), and it is hoped that these models will be adopted by the network of volcano observatories to better predict lava flow hazards.…”

Lava flow daily monitoring: the case of the 19 September–5 October 2022 eruption at Piton de la Fournaise

“…Both the sensors-retrieved data were processed by the Middle Infrared Observations of Volcanic Activity (MIROVA) system developed at the University of Turin, Italy * [Coppola et al 2016;Campus et al 2022]. MIROVA allows the heat radiated by the lava flow to be quantified at the time of the satellite acquisition and to be converted into Time-Averaged Discharge Rate (TADR) [Coppola et al 2013; with an uncertainty of ±35% [Harris et al 2017; * www.mirovaweb.it Chevrel et al 2022;Verdurme et al 2022]. The time series of TADR were manually filtered in order to discard the data contaminated by clouds and/or acquired in bad geometrical conditions.…”

“…In 2014, after 4 years of quiescence, Piton de la Fournaise entered a new cycle and between then and now (June 2023) it has erupted 24 times University of Turin, Italy). The dense monitoring network at Piton de la Fournaise, and expertise at OVPF-IPGP and its partners, has been therefore highly efficient at responding to effusive eruptions [Roult et al 2012;Bato et al 2016;Staudacher et al 2016;Harris et al 2017;Peltier et al 2018;Harris et al 2019;Peltier et al 2021;Chevrel et al 2022;Peltier et al 2022]. In parallel, a complete database of lava flow outlines since 1930 has been compiled using various techniques and includes, to date, more than 200 lava flows [Bachèlery 1981;Servadio 2011;Servadio et al 2012;Derrien 2019;Derrien et Presses universitaires de �rasbourg Since 2014, recurrent aerial surveys (from helicopter or ultra-light motorized planes, ULM) produced for SfM-MVS photogrammetry have been systematically done at the end of each eruption of Piton de la Fournaise and sometimes during the eruption (when the weather conditions and the timing of the eruption allow) to monitor the evolution of the flow field and to calculate the thickness and volume of the emitted lava flow [Derrien 2019;Derrien et al 2019].…”

“…Satellite data such as InSAR (satellite-based Interferometry of Synthetic Aperture Radar) coherence maps, Pléiades, ASTER and Sentinel-2 images have also been used to delimit lava flow coverage [Bato et al 2016;Harris et al 2017;. Furthermore, the monitoring and forecasting of lava flows at Piton de la Fournaise have been enhanced over the past years with the near realtime response protocol that has been systematically employed since 2018, providing lava flow hazard maps to the authorities within the first hours of the eruption [Chevrel et al 2022].…”

A new portable field rotational viscometer for high-temperature melts

“…The rheological properties of lava control lava flow emplacement dynamics including trajectories, velocities, and runout distances. These parameters are used to calibrate numerical models providing support to risk mitigation strategies [13][14][15][16][17] . Since the late 1980s, viscometry in the laboratory has been a common method that works with re-melted lava under a well-controlled environment (temperature, shear rate, oxygen fugacity) and allows for very precise measurements (< 0.01 log Pa•s) 10,18,19 .…”