scholarly journals Retrospective validation of a lava-flow hazard map for Mount Etna volcano

2011 ◽  
Vol 54 (5) ◽  
Author(s):  
Annalisa Cappello ◽  
Annamaria Vicari ◽  
Ciro Del Negro
Keyword(s):  
Lava Flow ◽  
Mount Etna ◽  
Hazard Map ◽  
Etna Volcano ◽  
Lava Flow Hazard

Optimizing barrier placement for lava flow hazard and risk mitigation

2020 ◽  
Author(s):  
Giuseppe Bilotta ◽  
Annalisa Cappello ◽  
Veronica Centorrino ◽  
Claudia Corradino ◽  
Gaetana Ganci ◽  
...  
Keyword(s):  
Lava Flow ◽  
Risk Mitigation ◽  
Flow Direction ◽  
Economic Loss ◽  
Lava Flows ◽  
Mount Etna ◽  
Area Of Interest ◽  
Lava Flow Hazard ◽  
Mitigation Action ◽  
The Impact

<p>Mitigating hazards when lava flows threaten infrastructure is one of the most challenging fields of volcanology, and has an immediate and practical impact on society. Lava flow hazard is determined by the probability of inundation, and essentially controlled by the topography of the area of interest. The most common actions of intervention for lava flow hazard mitigation are therefore the construction of artificial barriers and ditches that can control the flow direction and advancement speed. Estimating the effect a barrier or ditch can have on lava flow paths is non-trivial, but numerical modelling can provide a powerful tool by simulating the eruptive scenario and thus assess the effectiveness of the mitigation action. We present a numerical method for the design of optimal artificial barriers, in terms of location and geometric features, aimed at minimizing the impact of lava flows based on the spatial distribution of exposed elements. First, an exposure analysis collects information about elements at risk from different datasets: population per municipality, distribution of buildings, infrastructure, routes, gas and electricity networks, and land use; numerical simulations are used to compute the probability for these elements to be inundated by lava flows from a number of possible eruptive scenarios  (hazard assessment) and computing the associated economic loss and potential destruction of key facilities (risk assessment). We then generate several intervention scenarios, defined by the location, orientation and geometry (width, length, thickness and even shape) of multiple barriers, and compute the corresponding variation in economic loss. Optimality of the barrier placement is thus considered as a minimization problem for the economic loss, controlled by the barrier placement and constrained by the associated costs. We demonstrate the operation of this system by using a retrospective analysis of some recent effusive eruptions at Mount Etna, Sicily.</p>

Fast short-term lava flow hazard assessment with graph theory

2020 ◽  
Author(s):  
Veronica Centorrino ◽  
Giuseppe Bilotta ◽  
Annalisa Cappello ◽  
Gaetana Ganci ◽  
Claudia Corradino ◽  
...  
Keyword(s):  
Graph Theory ◽  
Lava Flow ◽  
Graph Representation ◽  
Computational Time ◽  
Hazard Map ◽  
Short Term ◽  
Flow Paths ◽  
Lava Flow Hazard ◽  
Mt Etna

<p>We explore the use of graph theory to assess short-term hazard of lava flow inundation, with Mt Etna as a case study. In the preparation stage, we convert into a graph the long-term hazard map produced using about 30,000 possible eruptive scenarios calculated by simulating lava flow paths with the physics-based MAGFLOW model. Cells in the original DEM-based representation are merged into graph vertices if reached by the same scenarios, and for each pair of vertices, a directed edge is defined, with an associated lava conductance (probability of lava flowing from one vertex to the other) computed from the number of scenarios that reach both the start and end vertex. In the application stage, the graph representation can be used to extract short-term lava flow hazard maps in case of unrest. When a potential vent opening area is identified e.g. from monitoring data, the corresponding vertices in the graph are activated, and the information about lava inundation probability is iteratively propagated to neighboring vertices through the edges, weighted according to the associated lava conductance. This allows quick identification of potentially inundated areas with little computational time. A comparison with the deterministic approach of subsetting and recomputing the weights in the long-term hazard map is also presented to illustrate benefits and downsides of the graph-based approach.</p>

Evaluating Lava Flow Hazard at Mount Etna (Italy) by a Cellular Automata Based Methodology

2010 ◽  
pp. 495-504 ◽  
Author(s):  
Maria Vittoria Avolio ◽  
Donato D’Ambrosio ◽  
Valeria Lupiano ◽  
Rocco Rongo ◽  
William Spataro
Keyword(s):  
Cellular Automata ◽  
Lava Flow ◽  
Mount Etna ◽  
Lava Flow Hazard

scholarly journals Lava flow hazard map of Piton de la Fournaise volcano 

2021 ◽  
Author(s):  
Oryaëlle Chevrel ◽  
Massimiliano Favalli ◽  
Villeneuve Nicolas ◽  
Andrew Harris ◽  
Alessandro Fornaciai ◽  
...  
Keyword(s):  
Lava Flow ◽  
18Th Century ◽  
Hot Spot ◽  
Hazard Map ◽  
Hazard Maps ◽  
Flow Paths ◽  
Piton De La Fournaise ◽  
Lava Flow Hazard ◽  
Multi Temporal ◽  
Deep Sources

<p>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 the establishment of the observatory in 1979. Eruptions are typically fissure-fed and form extensive lava flow fields. About 95 % of some ~250 historical events (since the first confidently dated eruption in 1708) have occurred inside an uninhabited horse-shoe shaped caldera (hereafter referred to as the Enclos) which is open to the ocean on its eastern side. Rarely (12 times since the 18th century), fissures have opened outside of the Enclos where housing units, population centers and infrastructure are at risk. In such a situation, lava flow hazard maps are a useful way of visualizing lava flow inundation probabilities over large areas. Here, we present a lava flow hazard map for Piton de la Fournaise volcano based on: i) vent distribution, ii) statistics of lava flow lengths, iii) lava flow recurrence times, and iv) simulations of lava flow paths across multi-temporal (i.e., regularly updated) topography using the DOWNFLOW stochastic numerical model. A map of the entire volcano highlights that the most probable (up to 12 %) location for future lava flow inundation is within the Enclos, where about 100,000 visitors are present each year. Hazard distribution changes throughout the analysis period due to the high frequency of eruptions that constantly modifies the vent opening distribution as well as the topography and the lava flow dimensional characteristics. Outside of the Enclos, probabilities reach 0.5 % along the well-defined rift zones and, although hazard occurrence in inhabited areas is deemed to be very low (<0.1 %), it may be underestimated here, as our study is only based on post-18th century records and neglects cycles of activity at the volcano. Specific hazard maps considering different event scenarios (i.e., events fed by different combinations of temporally evolving superficial and deep sources) are required to better assess affected areas in the future – especially by atypical, but potentially extremely hazardous, large volume eruptions. At such an active site, our method supports the need for regular updates of DEMs and associated lava flow hazard maps if we are to be effective in mitigating the associated risks.</p>

scholarly journals Lava flow hazard map of Piton de la Fournaise volcano

2021 ◽  
Vol 21 (8) ◽  
pp. 2355-2377
Author(s):  
Magdalena Oryaëlle Chevrel ◽  
Massimiliano Favalli ◽  
Nicolas Villeneuve ◽  
Andrew J. L. Harris ◽  
Alessandro Fornaciai ◽  
...  
Keyword(s):  
Lava Flow ◽  
Hazard Assessment ◽  
Land Use Planning ◽  
18Th Century ◽  
Hot Spot ◽  
Hazard Map ◽  
Hazard Maps ◽  
Piton De La Fournaise ◽  
Lava Flow Hazard

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

Supplementary material to "Lava flow hazard map of Piton de la Fournaise volcano"

2020 ◽  
Author(s):  
Magdalena Oryaëlle Chevrel ◽  
Massimiliano Favalli ◽  
Nicolas Villeneuve ◽  
Andrew J. L. Harris ◽  
Alessandro Fornaciai ◽  
...  
Keyword(s):  
Lava Flow ◽  
Hazard Map ◽  
Piton De La Fournaise ◽  
Lava Flow Hazard ◽  
Supplementary Material

scholarly journals Lava flow hazard map of Piton de la Fournaise volcano

2020 ◽  
Author(s):  
Magdalena Oryaëlle Chevrel ◽  
Massimiliano Favalli ◽  
Nicolas Villeneuve ◽  
Andrew J. L. Harris ◽  
Alessandro Fornaciai ◽  
...  
Keyword(s):  
Lava Flow ◽  
18Th Century ◽  
Hot Spot ◽  
Hazard Map ◽  
Flow Paths ◽  
Piton De La Fournaise ◽  
Lava Flow Hazard ◽  
Multi Temporal ◽  
La Réunion Island ◽  
Hazard Distribution

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 the establishment of the observatory in 1979. Eruptions are typically fissure-fed and form extensive lava flow fields. About 95 % of some ~250 historical events (since the first confidently dated eruption in 1708) have occurred inside an uninhabited horse-shoe shaped caldera (hereafter referred to as the Enclos) which is open to the ocean on its eastern side. Rarely (12 times since the 18th century), fissures have opened outside of the Enclos where housing units, population centers and infrastructure are at risk. In such a situation, lava flow hazard maps are a useful way of visualizing lava flow inundation probabilities over large areas. Here, we present a lava flow hazard map for Piton de la Fournaise volcano based on: i) vent distribution, ii) statistics of lava flow lengths, iii) lava flow recurrence times, and iv) simulations of lava flow paths across multi-temporal (i.e., regularly updated) topography using the DOWNFLOW stochastic numerical model. A map of the entire volcano highlights that the most probable (up to 12 %) location for future lava flow inundation is within the Enclos, where about 100,000 visitors are present each year. Hazard distribution changes throughout the analysis period due to the high frequency of eruptions that constantly modifies the vent opening distribution as well as the topography and the lava flow dimensional characteristics. Outside of the Enclos, probabilities reach 0.5 % along the well-defined rift zones and, although hazard occurrence in inhabited areas is deemed to be very low (

scholarly journals Anatomy of a Paroxysmal Lava Fountain at Etna Volcano: The Case of the 12 March 2021, Episode

2021 ◽  
Vol 13 (15) ◽  
pp. 3052
Author(s):  
Sonia Calvari ◽  
Alessandro Bonaccorso ◽  
Gaetana Ganci
Keyword(s):  
Lava Flow ◽  
Ground Deformation ◽  
Monitoring Network ◽  
Lava Flows ◽  
Etna Volcano ◽  
Lava Fountain ◽  
Eruptive Episode ◽  
Lava Fountains ◽  
Borehole Strainmeter ◽  
Ash Plume

On 13 December 2020, Etna volcano entered a new eruptive phase, giving rise to a number of paroxysmal episodes involving increased Strombolian activity from the summit craters, lava fountains feeding several-km high eruptive columns and ash plumes, as well as lava flows. As of 2 August 2021, 57 such episodes have occurred in 2021, all of them from the New Southeast Crater (NSEC). Each paroxysmal episode lasted a few hours and was sometimes preceded (but more often followed) by lava flow output from the crater rim lasting a few hours. In this paper, we use remote sensing data from the ground and satellite, integrated with ground deformation data recorded by a high precision borehole strainmeter to characterize the 12 March 2021 eruptive episode, which was one of the most powerful (and best recorded) among that occurred since 13 December 2020. We describe the formation and growth of the lava fountains, and the way they feed the eruptive column and the ash plume, using data gathered from the INGV visible and thermal camera monitoring network, compared with satellite images. We show the growth of the lava flow field associated with the explosive phase obtained from a fixed thermal monitoring camera. We estimate the erupted volume of pyroclasts from the heights of the lava fountains measured by the cameras, and the erupted lava flow volume from the satellite-derived radiant heat flux. We compare all erupted volumes (pyroclasts plus lava flows) with the total erupted volume inferred from the volcano deflation recorded by the borehole strainmeter, obtaining a total erupted volume of ~3 × 106 m3 of magma constrained by the strainmeter. This volume comprises ~1.6 × 106 m3 of pyroclasts erupted during the lava fountain and 2.4 × 106 m3 of lava flow, with ~30% of the erupted pyroclasts being remobilized as rootless lava to feed the lava flows. The episode lasted 130 min and resulted in an eruption rate of ~385 m3 s−1 and caused the formation of an ash plume rising from the margins of the lava fountain that rose up to 12.6 km a.s.l. in ~1 h. The maximum elevation of the ash plume was well constrained by an empirical formula that can be used for prompt hazard assessment.

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