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Laura J Connor - One of the best experts on this subject based on the ideXlab platform.

  • Deep and rapid thermo-mechanical erosion by a small-volume Lava Flow
    Earth and Planetary Science Letters, 2020
    Co-Authors: Elisabeth Gallant, Laura J Connor, Charles B Connor, Fanghui Deng, Timothy H. Dixon, Surui Xie, J.a. Saballos, C. Gutiérrez, D. Myhre, J. Zayac
    Abstract:

    Abstract We document remarkably efficient thermo-mechanical erosion by a small-volume Lava Flow. Downcutting by a basaltic-andesite Lava Flow on the steep-sided Momotombo volcano, Nicaragua, occurred at 100 times the rate commonly reported for thermal erosion in Lava Flow fields, even though this Flow was small-volume (0.02 km3) and effused at a low rate for

  • Lava Flow mapping and volume calculations for the 2012–2013 Tolbachik, Kamchatka, fissure eruption using bistatic TanDEM-X InSAR
    Bulletin of Volcanology, 2015
    Co-Authors: Julia Kubanek, Jacob A. Richardson, Sylvain J. Charbonnier, Laura J Connor
    Abstract:

    The bistatic acquisition mode of the German TanDEM-X radar satellite mission provides a reliable source for measuring morphological changes associated with volcanic activity. We present the use of this system to measure key Lava Flow parameters including thickness, volume, runout, and Flow extent by using two TanDEM-X data pairs to generate digital elevation models (DEMs) prior to and immediately following the 2012–2013 eruption of Tolbachik Volcano, Kamchatka. Morphometric parameters and areal distribution of the new Lava Flow field are determined using a cell-by-cell elevation difference between the two DEMs. A total Flow volume of 0.53 ± 0.07 km^3, a mean Flow thickness of 14.5 m, and a modal thickness of 7.8 m are calculated. We use these calculated Flow parameters as input to a volume-limited Lava Flow emplacement model. Model simulations are able to reproduce the SW portion of the 2012–2013 Tolbachik Lava Flow using a 75-m Shuttle Radar Topography Mission (SRTM) DEM and the 15-m TanDEM-X derived DEM, with goodness-of-fit measures of 56.3 and 59.6 %, respectively, based on the Jaccard similarity coefficient. The Flow simulation done using SRTM data underestimates the observed 14.4 km Flow runout by over 3 km, while the simulation with TanDEM-X data overestimates Flow runout by about 1.5 km. Performance of the Lava Flow modeling algorithm is highly dependent on the modal Lava thickness, highlighting the importance of using TanDEM-X DEMs to provide precise Lava Flow measurements in order to constrain input parameters for numerical modeling of Lava Flows.

  • Lava Flow mapping and volume calculations for the 2012 2013 tolbachik kamchatka fissure eruption using bistatic tandem x insar
    Bulletin of Volcanology, 2015
    Co-Authors: Julia Kubanek, J A Richardson, Sylvain J. Charbonnier, Laura J Connor
    Abstract:

    The bistatic acquisition mode of the German TanDEM-X radar satellite mission provides a reliable source for measuring morphological changes associated with volcanic activity. We present the use of this system to measure key Lava Flow parameters including thickness, volume, runout, and Flow extent by using two TanDEM-X data pairs to generate digital elevation models (DEMs) prior to and immediately following the 2012–2013 eruption of Tolbachik Volcano, Kamchatka. Morphometric parameters and areal distribution of the new Lava Flow field are determined using a cell-by-cell elevation difference between the two DEMs. A total Flow volume of 0.53 ± 0.07 km3, a mean Flow thickness of 14.5 m, and a modal thickness of 7.8 m are calculated. We use these calculated Flow parameters as input to a volume-limited Lava Flow emplacement model. Model simulations are able to reproduce the SW portion of the 2012–2013 Tolbachik Lava Flow using a 75-m Shuttle Radar Topography Mission (SRTM) DEM and the 15-m TanDEM-X derived DEM, with goodness-of-fit measures of 56.3 and 59.6 %, respectively, based on the Jaccard similarity coefficient. The Flow simulation done using SRTM data underestimates the observed 14.4 km Flow runout by over 3 km, while the simulation with TanDEM-X data overestimates Flow runout by about 1.5 km. Performance of the Lava Flow modeling algorithm is highly dependent on the modal Lava thickness, highlighting the importance of using TanDEM-X DEMs to provide precise Lava Flow measurements in order to constrain input parameters for numerical modeling of Lava Flows.

  • Probabilistic approach to modeling Lava Flow inundation: a Lava Flow hazard assessment for a nuclear facility in Armenia
    Journal of Applied Volcanology, 2012
    Co-Authors: Laura J Connor, Charles B Connor, Khachatur Meliksetian, Ivan Savov
    Abstract:

    Probabilistic modeling of Lava Flow hazard is a two-stage process. The first step is an estimation of the possible locations of future eruptive vents followed by an estimation of probable areas of inundation by Lava Flows issuing from these vents. We present a methodology using this two-stage approach to estimate Lava Flow hazard at a nuclear power plant site near Aragats, a Quaternary volcano in Armenia.

Tracy K. P. Gregg - One of the best experts on this subject based on the ideXlab platform.

  • Patterns and processes: Subaerial Lava Flow morphologies: A review
    Journal of Volcanology and Geothermal Research, 2017
    Co-Authors: Tracy K. P. Gregg
    Abstract:

    Abstract Most Lava Flows have been emplaced away from the watchful eyes of volcanologists, so there is a desire to use solidified Lava-Flow morphologies to reveal important information about the eruption that formed them. Our current understanding of the relationship between solidified basaltic Lava morphology and the responsible eruption and emplacement processes is based on decades of fieldwork, laboratory analyses and simulations, and computer models. These studies have vastly improved our understanding of the complex interactions between the solids, liquids, and gases that comprise cooling Lava Flows. However, the complex interactions (at millimeter and sub-millimeter scales) between the temperature-dependent abundances of the distinct phases that comprise a Lava Flow and the final morphology remain challenging to model and to predict. Similarly, the complex behavior of an active pahoehoe Flow, although almost ubiquitous on Earth, remains difficult to quantitatively model and precisely predict.

  • a laboratory investigation into the effects of slope on Lava Flow morphology
    Journal of Volcanology and Geothermal Research, 2000
    Co-Authors: Tracy K. P. Gregg, Jonathan H. Fink
    Abstract:

    Abstract In an attempt to model the effect of slope on the dynamics of Lava Flow emplacement, four distinct morphologies were repeatedly produced in a series of laboratory simulations where polyethylene glycol (PEG) was extruded at a constant rate beneath cold sucrose solution onto a uniform slope which could be varied from 1° through 60°. The lowest extrusion rates and slopes, and highest cooling rates, produced Flows that rapidly crusted over and advanced through bulbous toes, or pillows (similar to subaerial “toey” pahoehoe Flows and to submarine pillowed Flows). As extrusion rate and slope increased, and cooling rate decreased, pillowed Flows gave way to rifted Flows (linear zones of liquid wax separated by plates of solid crust, similar to what is observed on the surface of convecting Lava lakes), then to folded Flows with surface crusts buckled transversely to the Flow direction, and, at the highest extrusion rates and slopes, and lowest cooling rates, to leveed Flows, which solidified only at their margins. A dimensionless parameter, Ψ , primarily controlled by effusion rate, cooling rate and Flow viscosity, quantifies these Flow types. Increasing the underlying slope up to 30° allows the liquid wax to advance further before solidifying, with an effect similar to that of increasing the effusion rate. For example, conditions that produce rifted Flows on a 10° slope result in folded Flows on a 30° slope. For underlying slopes of 40°, however, this trend reverses, slightly owing to increased gravitational forces relative to the strength of the solid wax. Because of its significant influence on heat advection and the disruption of a solid crust, slope must be incorporated into any quantitative attempt to correlate eruption parameters and Lava Flow morphologies. These experiments and subsequent scaling incorporate key physical parameters of both an extrusion and its environment, allowing their results to be used to interpret Lava Flow morphologies on land, on the sea floor, and on other planets.

  • Submarine Lava-Flow inflation: A model for the formation of Lava pillars
    Geology, 1996
    Co-Authors: Tracy K. P. Gregg, William W. Chadwick
    Abstract:

    Lava pillars are commonly observed in volcanic terrains at mid-ocean ridges and are unique to the submarine volcanic environment; they are hollow pipes that extend from the base of a Lava Flow to remnants of its collapsed upper crust. Pillars can be as tall as 5 m and have outer diameters typically between 0.5 and 2 m. Previous models proposed that they form in thick, fluid, fast-moving sheet Flows. We present a new model for pillar formation based on sea-floor observations, and on results from laboratory and numerical models, in which Lava pillars form within initially thin (

  • Quantification of extraterrestrial Lava Flow effusion rates through laboratory simulations
    Journal of Geophysical Research: Planets, 1996
    Co-Authors: Tracy K. P. Gregg, Jonathan H. Fink
    Abstract:

    We have used carefully controlled laboratory simulations to develop a model which relates Lava Flow morphology to effusion rate and rheology. Through comparisons with measured and estimated eruption rates on Earth, this approach allows us to constrain eruptive styles and compositions of extraterrestrial Lava Flows. By applying this model to Lava Flows on the Moon, Mars and Venus, we have determined that all the common Flow morphologies (domes, folds and levees) on these planets could have been produced by basalt-like or andesite-like Lavas through either continuous or episodic emplacement. The presence of more evolved magma compositions on other planets is not required to explain any of the observed Lava Flow morphologies

  • quantification of submarine Lava Flow morphology through analog experiments
    Geology, 1995
    Co-Authors: Tracy K. P. Gregg, Jonathan H. Fink
    Abstract:

    We developed a technique for determining paleoeffusion rates and emplacement times for submarine Lava Flows, using observations of Flow morphology and estimates of eruption volume, eruption temperature, Lava viscosity, and preFlow topography. Using laboratory simulations, and correlating these results with sea-floor observations, four submarine Lava-Flow morphologies are considered to be diagnostic of specific effusion rates: jumbled, folded, and lineated sheets, and striated pillows. We applied this approach to the CoAxial Flow, emplaced in less than 14 days on the Juan de Fuca Ridge in early summer, 1993, and we calculated an effusion rate of ∼100 m3/s, giving an emplacement time of ∼10 days.

Ciro Del Negro - One of the best experts on this subject based on the ideXlab platform.

  • Optimizing barrier placement for Lava Flow hazard and risk mitigation
    2020
    Co-Authors: Giuseppe Bilotta, Gaetana Ganci, Annalisa Cappello, Veronica Centorrino, Claudia Corradino, Ciro Del Negro
    Abstract:

    <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>

  • Emplacement conditions of the 1256 AD Al-Madinah Lava Flow field in Harrat Rahat, Kingdom of Saudi Arabia — Insights from surface morphology and Lava Flow simulations
    Journal of Volcanology and Geothermal Research, 2016
    Co-Authors: Gábor Kereszturi, Gaetana Ganci, Annalisa Cappello, Ciro Del Negro, Károly Németh, Mohammed Rashad Moufti, Hugo Murcia, Jonathan Procter, Hani Zahran
    Abstract:

    Abstract Lava Flow hazard modelling requires detailed geological mapping, and a good understanding of emplacement settings and the processes involved in the formation of Lava Flows. Harrat Rahat, Kingdom of Saudi Arabia, is a large volcanic field, comprising about 1000 predominantly small-volume volcanoes most of which have emitted Lava Flows of various lengths. A few eruptions took place in this area during the Holocene, and they were located in the northern extreme of the Harrat Rahat, a close proximity to critical infrastructure and population living in Al-Madinah City. In the present study, we combined field work, high resolution digital topography and morphometric analysis to infer the emplacement history of the last historical event in the region represented by the 1256 AD Al-Madinah Lava Flow field. These data were also used to simulate 1256 AD-type Lava Flows in the Harrat Rahat by the MAGFlow Lava Flow emplacement model, which is able to relate the Flow evolution to eruption conditions. The 1256 AD Lava Flow field extent was mapped at a scale of 1:1000 from a high resolution (0.5 m) Light Detection And Ranging (LiDAR) Digital Terrain Model (DTM), aerial photos with field support. The bulk volume of the Lava Flow field was estimated at 0.4 km3, while the source volume represented by seven scoria cone was estimated at 0.023 km3. The Lava Flow covered an area of 60 km2 and reached a maximum length of 23.4 km. The Lava Flow field comprises about 20.9% of pāhoehoe, 73.8% of 'a'ā, and 5.3% of late-stage outbreaks. Our field observation, also suggests that the Lava Flows of the Harrat Rahat region are mainly core-dominated and that they formed large Lava Flow fields by amalgamation of many single channels. These channels mitigated downslope by topography-Lava Flow and channel–channel interactions, highlighting this typical process that needs to be considered in the volcanic hazard assessment in the region. A series of numerical Lava Flow simulations was carried out using a range of water content (0.1–1 wt.%), solidification temperature (800–600 °C) and effusion curves (simple and complex curves). These simulations revealed that the MAGFlow code is sensitive to the changes of water content of the erupting Lava magma, while it is less sensitive to solidification temperature and the changes of the shape of effusion curve. The advance rate of the simulated Lava Flows changed from 0.01 to 0.22 km/h. Using data and observations from the youngest volcanic event of the Harrat Rahat as input parameters to MAGFlow code, it is possible to provide quantitative limits on this type of hazard.

  • Quantifying Lava Flow hazards in response to effusive eruption
    Geological Society of America Bulletin, 2015
    Co-Authors: Ciro Del Negro, Annalisa Cappello, Gaetana Ganci
    Abstract:

    The integration of satellite data and modeling represents a step toward the next generation of quantitative hazard assessment in response to effusive volcano eruption onset. Satellite-based thermal remote sensing of hotspots related to effusive activity can effectively provide a variety of products suited to timing, locating, and tracking the radiant character of Lava Flows. Hotspots show the location and occurrence of eruptive events (vents). Discharge rate estimates may indicate the current intensity (effusion rate) and potential magnitude (volume). High-spatial-resolution multispectral satellite data can complement field observations for monitoring the front position (length) and extension of Flows (area). Physics-based models driven, or validated, by satellite-derived parameters are now capable of fast and accurate forecast of Lava Flow inundation scenarios (hazard). Here, we demonstrate the potential of the integrated application of satellite remote-sensing techniques and Lava Flow models by using a retrospective analysis of the 2004–2005 effusive eruption at Mount Etna in Italy. The Lava Flow hazard was assessed by using the HOTSAT volcano hotspot detection system, which works with satellite thermal infrared data, and the MAGFlow Lava Flow emplacement model, which is able to relate the Flow evolution to eruption conditions at the vent. We used HOTSAT to analyze Moderate Resolution Imaging Spectroradiometer (MODIS) and Spinning Enhanced Visible and InfraRed Imager (SEVIRI) data to output hotspot location, Lava thermal flux, and effusion rate estimation. This output was used to drive the MAGFlow simulations of Lava Flow paths and to continuously update Flow simulations. We also show how Landsat-7 Enhanced Thematic Mapper+ (ETM+) and Earth Observing 1 ( EO-1 ) Advanced Land Imager (ALI) images complement the field observations to track the Flow front position in time and add valuable data on Lava Flow advancement with which to validate the numerical simulations. Such integration at last makes timely forecasts of Lava Flow hazards during effusive crises possible at the great majority of volcanoes for which no monitoring exists.

  • MAGFlow: a physics-based model for the dynamics of Lava-Flow emplacement
    Geological Society London Special Publications, 2015
    Co-Authors: Annalisa Cappello, Gaetana Ganci, Alexis Hérault, Giuseppe Bilotta, Ciro Del Negro
    Abstract:

    The MAGFlow model for Lava-Flow simulations is based on the cellular automaton (CA) approach, and uses a physical model for the thermal and rheological evolution of the Flowing Lava. We discuss the potential of MAGFlow to improve our understanding of the dynamics of Lava-Flow emplacement and our ability to assess Lava-Flow hazards. Sensitivity analysis of the input parameters controlling the evolution function of the automaton demonstrates that water content and solidus temperatures are the parameters to which MAGFlow is most sensitive. Additional tests also indicate that temporal changes in effusion rate strongly influence the accuracy of the predictive modelling of Lava-Flow paths. The parallel implementation of MAGFlow on graphic processing units (GPUs) can achieve speed-ups of two orders of magnitude relative to the corresponding serial implementation, providing a Lava-Flow simulation spanning several days of eruption in just a few minutes. We describe and demonstrate the operation of MAGFlow using two case studies from Mt Etna: one is a reconstruction of the detailed chronology of the Lava-Flow emplacement during the 2006 flank eruption; and the other is the production of the Lava-Flow hazard map of the persistent eruptive activity at the summit craters.Published3V. Dinamiche e scenari eruttiviN/A or not JCRrestricte

  • Lava Flow hazards-An impending threat at Miyakejima volcano, Japan
    Journal of Volcanology and Geothermal Research, 2015
    Co-Authors: Annalisa Cappello, Nobuo Geshi, Marco Neri, Ciro Del Negro
    Abstract:

    Abstract The majority of the historic eruptions recorded at Miyakejima volcano were fissure eruptions that occurred on the flanks of the volcano. During the last 1100 years, 17 fissure eruptions have been reported with a mean interval of about 76–78 years. In the last century, the mean interval between fissure eruptions decreased to 21–22 years, increasing significantly the threat of Lava Flow inundations to people and property. Here we quantify the Lava Flow hazards posed by effusive eruptions in Miyakejima by combining field data, numerical simulations and probability analysis. Our analysis is the first to assess both the spatiotemporal probability of vent opening, which highlights the areas most likely to host a new eruption, and the Lava Flow hazard, which shows the probabilities of Lava-Flow inundation in the next 50 years. Future eruptive vents are expected in the vicinity of the Hatchodaira caldera, radiating from the summit of the volcano toward the costs. Areas more likely to be threatened by Lava Flows are Ako and Kamitsuki villages, as well as Miike port and Miyakejima airport. Thus, our results can be useful for risk evaluation, investment decisions, and emergency response preparation.

Jonathan H. Fink - One of the best experts on this subject based on the ideXlab platform.

  • a laboratory investigation into the effects of slope on Lava Flow morphology
    Journal of Volcanology and Geothermal Research, 2000
    Co-Authors: Tracy K. P. Gregg, Jonathan H. Fink
    Abstract:

    Abstract In an attempt to model the effect of slope on the dynamics of Lava Flow emplacement, four distinct morphologies were repeatedly produced in a series of laboratory simulations where polyethylene glycol (PEG) was extruded at a constant rate beneath cold sucrose solution onto a uniform slope which could be varied from 1° through 60°. The lowest extrusion rates and slopes, and highest cooling rates, produced Flows that rapidly crusted over and advanced through bulbous toes, or pillows (similar to subaerial “toey” pahoehoe Flows and to submarine pillowed Flows). As extrusion rate and slope increased, and cooling rate decreased, pillowed Flows gave way to rifted Flows (linear zones of liquid wax separated by plates of solid crust, similar to what is observed on the surface of convecting Lava lakes), then to folded Flows with surface crusts buckled transversely to the Flow direction, and, at the highest extrusion rates and slopes, and lowest cooling rates, to leveed Flows, which solidified only at their margins. A dimensionless parameter, Ψ , primarily controlled by effusion rate, cooling rate and Flow viscosity, quantifies these Flow types. Increasing the underlying slope up to 30° allows the liquid wax to advance further before solidifying, with an effect similar to that of increasing the effusion rate. For example, conditions that produce rifted Flows on a 10° slope result in folded Flows on a 30° slope. For underlying slopes of 40°, however, this trend reverses, slightly owing to increased gravitational forces relative to the strength of the solid wax. Because of its significant influence on heat advection and the disruption of a solid crust, slope must be incorporated into any quantitative attempt to correlate eruption parameters and Lava Flow morphologies. These experiments and subsequent scaling incorporate key physical parameters of both an extrusion and its environment, allowing their results to be used to interpret Lava Flow morphologies on land, on the sea floor, and on other planets.

  • Quantification of extraterrestrial Lava Flow effusion rates through laboratory simulations
    Journal of Geophysical Research: Planets, 1996
    Co-Authors: Tracy K. P. Gregg, Jonathan H. Fink
    Abstract:

    We have used carefully controlled laboratory simulations to develop a model which relates Lava Flow morphology to effusion rate and rheology. Through comparisons with measured and estimated eruption rates on Earth, this approach allows us to constrain eruptive styles and compositions of extraterrestrial Lava Flows. By applying this model to Lava Flows on the Moon, Mars and Venus, we have determined that all the common Flow morphologies (domes, folds and levees) on these planets could have been produced by basalt-like or andesite-like Lavas through either continuous or episodic emplacement. The presence of more evolved magma compositions on other planets is not required to explain any of the observed Lava Flow morphologies

  • quantification of submarine Lava Flow morphology through analog experiments
    Geology, 1995
    Co-Authors: Tracy K. P. Gregg, Jonathan H. Fink
    Abstract:

    We developed a technique for determining paleoeffusion rates and emplacement times for submarine Lava Flows, using observations of Flow morphology and estimates of eruption volume, eruption temperature, Lava viscosity, and preFlow topography. Using laboratory simulations, and correlating these results with sea-floor observations, four submarine Lava-Flow morphologies are considered to be diagnostic of specific effusion rates: jumbled, folded, and lineated sheets, and striated pillows. We applied this approach to the CoAxial Flow, emplaced in less than 14 days on the Juan de Fuca Ridge in early summer, 1993, and we calculated an effusion rate of ∼100 m3/s, giving an emplacement time of ∼10 days.

Annamaria Vicari - One of the best experts on this subject based on the ideXlab platform.

  • sensitivity analysis of the magFlow cellular automaton model for Lava Flow simulation
    Environmental Modelling and Software, 2012
    Co-Authors: Giuseppe Bilotta, Annamaria Vicari, Annalisa Cappello, Alexis Hérault, Giovanni Russo, Ciro Del Negro
    Abstract:

    MAGFlow is a physics-based numerical model for Lava Flow simulations based on the Cellular Automaton approach that has been successfully used to predict the Lava Flow paths during the recent eruptions on Mt Etna. We carried out an extensive sensitivity analysis of the physical and rheological parameters that control the evolution function of the automaton and which are measured during eruptive events, in an effort to verify the reliability of the model and improve its applicability to scenario forecasting. The results obtained, which include Sobol' sensitivity indices computed using polynomial chaos expansion, confirm the consistency of MAGFlow with the underlying physical model and identify water content and solidus temperature as critical parameters for the automaton. Additional tests also indicate that flux rates can have a strong influence on the emplacement of Lava Flows, and that to obtain more accurate simulations it is better to have continuous monitoring of the effusion rates, even if with moderate errors, rather than sparse accurate measurements.

  • an emergent strategy for volcano hazard assessment from thermal satellite monitoring to Lava Flow modeling
    Remote Sensing of Environment, 2012
    Co-Authors: Gaetana Ganci, Annamaria Vicari, Annalisa Cappello, Ciro Del Negro
    Abstract:

    Abstract Spaceborne remote sensing techniques and numerical simulations have been combined in a web-GIS framework (LAV@HAZARD) to evaluate Lava Flow hazard in real time. By using the HOTSAT satellite thermal monitoring system to estimate time-varying TADR (time averaged discharge rate) and the MAGFlow physics-based model to simulate Lava Flow paths, the LAV@HAZARD platform allows timely definition of parameters and maps essential for hazard assessment, including the propagation time of Lava Flows and the maximum run-out distance. We used LAV@HAZARD during the 2008–2009 Lava Flow-forming eruption at Mt Etna (Sicily, Italy). We measured the temporal variation in thermal emission (up to four times per hour) during the entire duration of the eruption using SEVIRI and MODIS data. The time-series of radiative power allowed us to identify six diverse thermal phases each related to different dynamic volcanic processes and associated with different TADRs and Lava Flow emplacement conditions. Satellite-derived estimates of Lava discharge rates were computed and integrated for the whole period of the eruption (almost 14 months), showing that a Lava volume of between 32 and 61 million cubic meters was erupted of which about 2/3 was emplaced during the first 4 months. These time-varying discharge rates were then used to drive MAGFlow simulations to chart the spread of Lava as a function of time. TADRs were sufficiently low ( 3 /s) that no Lava Flows were capable of Flowing any great distance so that they did not pose a hazard to vulnerable (agricultural and urban) areas on the flanks of Etna.

  • Retrospective validation of a Lava Flow hazard map for Mount Etna volcano
    Annals of Geophysics, 2011
    Co-Authors: Annalisa Cappello, Annamaria Vicari, Ciro Del Negro
    Abstract:

    This report presents a retrospective methodology to validate a long-term hazard map related to Lava-Flow invasion at Mount Etna, the most active volcano in Europe. A Lava-Flow hazard map provides the probability that a specific point will be affected by potential destructive volcanic processes over the time period considered. We constructed this Lava-Flow hazard map for Mount Etna volcano through the identification of the emission regions with the highest probabilities of eruptive vents and through characterization of the event types for the numerical simulations and the computation of the eruptive probabilities. Numerical simulations of Lava-Flow paths were carried out using the MAGFlow cellular automata model. To validate the methodology developed, a hazard map was built by considering only the eruptions that occurred at Mount Etna before 1981. On the basis of the probability of coverage by Lava Flows, the map was divided into ten classes, and two fitting scores were calculated to measure the overlap between the hazard classes and the actual shapes of the Lava Flows that occurred after 1981.

  • numerical simulation of Lava Flow using a gpu sph model
    Annals of Geophysics, 2011
    Co-Authors: Alexis Hérault, Annamaria Vicari, Giuseppe Bilotta, Eugenio Rustico, Ciro Del Negro
    Abstract:

    A smoothed particle hydrodynamics (SPH) method for Lava-Flow modeling was implemented on a graphical processing unit (GPU) using the compute unified device architecture (CUDA) developed by NVIDIA. This resulted in speed-ups of up to two orders of magnitude. The three-dimensional model can simulate Lava Flow on a real topography with free-surface, non-Newtonian fluids, and with phase change. The entire SPH code has three main components, neighbor list construction, force computation, and integration of the equation of motion, and it is computed on the GPU, fully exploiting the computational power. The simulation speed achieved is one to two orders of magnitude faster than the equivalent central processing unit (CPU) code. This GPU implementation of SPH allows high resolution SPH modeling in hours and days, rather than in weeks and months, on inexpensive and readily available hardware.

  • mitigation of Lava Flow invasion hazard through optimized barrier configuration aided by numerical simulation the case of the 2001 etna eruption
    Journal of Volcanology and Geothermal Research, 2010
    Co-Authors: Silvia Scifoni, Annamaria Vicari, Maria Marsella, Cristina Proietti, M Coltelli, Q Napoleoni, C. Del Negro
    Abstract:

    Abstract Lava Flow spreading along the flanks of Etna volcano often produces damages to the land and proprieties. The impact of these eruptions could be mitigated by building artificial barriers for controlling and slowing down the Lava, as recently experienced in 1983, 1991–1993, 2001 and 2002. This study investigates how numerical simulations can be adopted for evaluating the effectiveness of barrier construction and for optimizing their geometry, considering as test case the Lava Flows emplaced on Etna's south flank during 2001. The Flow temporal evolutions were reconstructed deriving the effusion rate trends, together with the pre-eruption topography were adopted as input data of the MAGFlow simulation code. Three simulations were then conducted to simulate Lava Flow with and without barriers. The first aimed at verifying the reconstruction of the effusion rate trends, while the others at assessing the performance of the barrier system realized during the eruption in comparison with an alternative solution here proposed. A quantitative analysis carried out on the first simulation confirms the suitability of the selected test case. The comparison of the three simulated thickness distributions showed both the effectiveness of the barriers in slowing down the Lava Flow and the sensitivity of the MAGFlow code to the topographical variations represented by the barriers. Finally, for reducing both the time necessary to erect the barrier and the barrier environmental impact, the gabion's barrier construction was analyzed. The implemented and tested procedure enforces the capability of using numerical simulations for designing optimized Lava Flow barriers aimed at making swifter mitigatory actions upon Lava Flows and improving the effectiveness of civil protection interventions during emergencies.