Traductionsen contexte de "pression de sortie comprise" en français-anglais avec Reverso Context : La solution aqueuse liquide sort de l'Ă©lĂ©ment chauffant Ă  une pression de sortie comprise entre les pressions de pompe et de rĂ©servoir. Research Open Access Published 13 August 2022 Virginie Pinel2, JoaquĂ­n M. C. Belart3,4, Marcello De Michele5, Catherine Proy6, Claire Tinel6, Etienne Berthier7, Yannick GuĂ©henneux1, Magnus Tumi Gudmundsson4, Birgir V. Óskarsson8, Shan Gremion9, Daniel Raucoules5, SĂ©bastien Valade10, Francesco Massimetti11 & Bjorn Oddsson12 Journal of Applied Volcanology volume 11, Article number 10 2022 Cite this article 103 Accesses 3 Altmetric Metrics details AbstractWithin the framework of the CIEST2 Cellule d'Intervention d'Expertise Scientifique et Technique new generation and thanks to the support of CNES, the French space agency, the first phase of the Fagradalsfjall eruption was exceptionally well covered by high resolution optical satellite data, through daily acquisitions of PlĂ©iades images in stereo mode. In this study, we show how PlĂ©iades data provided real-time information useful for the operational monitoring of the ongoing eruption. An estimation of the volume of lava emitted as well as the corresponding effusion rate could be derived and delivered to the civil protection less than 6 h after the data acquisition. This information is complementary to and consistent with estimates obtained through the HOTVOLC service using SEVIRI Spinning Enhanced Visible and Infrared Imager sensor on-board Meteosat Second Generation MGS geostationary satellites, operated by the European Space Agency ESA, characterized by a lower spatial resolution and a higher temporal one. In addition to the information provided on the lava emission, PlĂ©iades data also helped characterize the intensity of the eruption by providing insight into the elevation and the velocity of the volcanic plume. The survey of this effusive eruption, well anticipated by a series of precursors, is a proof of concept of the efficiency of optical/thermal satellite data for volcanic crisis real-time monitoring. IntroductionLava flows on the ground and related atmospheric ash/SO2 emissions induced by the volcanic activity are common hazards occurring during eruptions and can represent a threat to the population living in the vicinity of volcanoes areas Allen et al., 2000; Vicari et al., 2011. Effusion rates and degassing are key information on the intensity of the eruption, the driving forces leading to magma ascent and thus the temporal evolution of the event. Today, operational monitoring of volcanic products is achieved through both in-situ measurements and ground-based instruments Marzano et al., 2006; Calvari et al., 2011; Gouhier et al., 2012; Aiuppa et al., 2015; Di Traglia et al., 2021. The development of ground-based remote sensing tools, such as those aimed at studying lava flows propagation, open vent degassing, or ash emissions are now part of routine monitoring operations at many volcanoes Scollo et al., 2009; Barsotti et al., 2020; Peltier et al., 2021; Kelfoun et al., 2021. However, for volcanoes located in remote areas, where the installation and maintenance of expensive instruments network is difficult, satellite-based techniques are more beneficial if satellite remote sensing systems can provide a rapid assessment of volcanic activity Schmidt et al., 2015; Gouhier et al., 2016; Coppola et al., 2016a, b; Dumont et al., 2018; Valade et al., 2019; Albino et al., 2020. This is particularly important as such data can potentially be used to derive crucial information for decision makers. Yet the provision of accurate data in a timely fashion remains very challenging from space as sensors on-board Low-Earth Orbiting LEO platforms with very high spatial resolutions usually have low frequency of acquisition such as PlĂ©iades, while sensors on-board geostationary GEO platforms with very high acquisition rate suffer from low spatial resolution such as MSG satellites.Satellites have already been extensively used to produce digital elevation models DEMs in volcanic areas and infer the volume of eruptive deposits by comparing the differences between a DEM obtained after the emplacement of deposits with a pre-eruptive DEM. While most studies are based on TanDEM-X bistatic radar data Albino 2015, Bato 2016, Albino 2020, some use high-resolution PlĂ©iades optical data acquired in stereo mode Bagnardi et al 2016; Carrara et al 2019. For the October 2010 effusive eruption of Piton de la Fournaise, RĂ©union Island, Bato et al, 2016 made a direct comparison of mean effusion rates derived by DEMs differentiation and by thermal anomalies quantification from MODIS data and demonstrated a fairly good agreement between the two independent dataset. While the growth rate of domes has been estimated from PlĂ©iades imagery Pinel et al., 2020; Moussallam et al, 2021, until now, optical satellite imagery has never been used to estimate the temporal evolution of the volume of magma emitted during a lava flow emplacement event, providing only an estimate of the total volume of the emplaced lava flow. However, there are a few examples of studies providing the temporal evolution of the eruptive rate based on TanDEM-X data Poland 2014, Arnold 2017, Kubanek 2017. However, all these studies were performed a posteriori and, so far, satellite imagery has never provided real-time DEMs for operational monitoring. The time evolution of effusion rates can also be obtained from MidWave InfraRed MWIR satellite imagery either from LEO platforms such as Terra-MODIS providing time-average effusion rates Wright et al., 2001; Coppola et al., 2016a, b, or from GEO platforms such as Meteosat-SEVIRI, providing instantaneous effusion rates Ganci et al., 2012; Gouhier et al., 2016. A comparison of the cumulative volume estimated by SEVIRI and DEM difference has been performed a posteriori for the 2015 eruption of Etna Ganci et al. 2019a. The volume derived from SEVIRI data was 20% smaller than that estimated from the difference between DEMs, which was interpreted by the authors as resulting from lava porosity. Interestingly, Sentinel-2 satellite ESA-Copernicus providing ShortWave InfraRed SWIR data fills the gap between PlĂ©iades Optical and Meteosat MWIR data in terms of temporal and spatial resolutions. In particular, it allows an attractive compromise for the monitoring of effusive eruptions and the cartography of lava flow field Valade et al., 2019; Massimetti et al., 2020. Finally, the coherence of radar data can also be used in real time to derive the evolution of the surface covered by the lava Ebmeier et al., 2012; Kubanek et al., 2015; Valade et al., 2019; Richter and Froger 2020.In order to promote the use of satellite data for hazards studies and mitigation, two French initiatives have been undertaken. i The Technical-Scientific Intervention and expertise unit CIEST2 – Cellule d'Intervention d'Expertise Scientifique et Technique new generation, was created in 2019 following the expression of interest of about 30 French scientists. The objective is to extend and facilitate the acquisition and use of very high optical images from PlĂ©iades acquired under the International Charter "Space and Major Disasters", for the understanding and study of geological hazards. The CIEST2 initiative is now placed in the framework of the solid Earth national data and services pole Formter. ii In parallel, HOTVOLC is a geostationary satellite-data-driven service dedicated to the real-time monitoring of active volcanoes, allowing lava hot spots, ash and SO2 clouds products to be detected and tracked at an acquisition rate of one image every 15 min Gouhier et al., 2016; 2020. HOTVOLC uses Meteosat-SEVIRI infrared images and is part of the National Observation Service for Volcanology SNOV – Service National des Observations en Volcanologie operated by the CNRS Centre National de la Recherche Scientifique. Its mission is to ensure continuous and permanent monitoring of French volcanoes, as well as volcanic targets Italy, Iceland, Lesser Antilles, etc. whose products may affect French this context, the recent Icelandic eruption of Mt. Fagradalsfjall in the Reykjanes Peninsula, which started on March 19, 2021 offers a very good opportunity to demonstrate the ability of the CIEST2 and HOTVOLC initiatives to provide a rapid and concerted response to gather crucial information useful for making informed decisions. The Fagradalsfjall eruption was closely monitored with remote sensing data through the CIEST2, HOTVOLC and MOUNTS initiatives during the first 10 days of the eruption, and through the entire eruption using a large amount of airborne data Pedersen et al., 2022. The eruption is a long-term basaltic effusive eruption that initiated as a fissure eruption on 19 March 2021 within an enclosed valley, accompanied by small lava fountains which ended on 18 september. In this paper, we present the two French initiatives CIEST2 and HOTVOLC with associated methodology, and discuss their capabilities and limitations, as well as the major interest of coupling these two approaches. We also present the potential contribution of Sentinel-2 data for the estimation of lava surface from the operational platforms MOUNTS. Then, we describe the results obtained from PlĂ©iades and Meteosat data. This comprises, in particular, the estimation of lava flows volume and volcanic plume elevation from PlĂ©iades DEMs, as well as the comparison between average and instantaneous lava discharge rates using PlĂ©iades and Meteosat images, respectively. We also provide airborne data at very high spatial resolution, hereafter used as a validation of satellite-based initiatives for a rapid response using CNES/ESA spatial resourcesCIEST2 Technical-Scientific Intervention and expertise unitCIEST2 is a French initiative aiming at fostering cooperation of the geophysical community around the use of satellite imagery for geohazards monitoring and understanding. This synergy between CNES the French Space Agency and the French “solid Earth” community aims at a quick response in the programming and use of Earth observation resources, in the event of a geophysical hazard. The goal of the initiative is to analyze and process space imagery to ultimately improve our knowledge of a geophysical initiative started in 2005 as a formal agreement between six national organizations BRGM, CEA, INSU, IPGP, IRD, UCBL which aimed to extend the use of space resources, in particular the SPOT images acquired within the framework of the International Charter on Space and Major Disasters, for the study and understanding of geophysical hazards. Today 2022 the CIEST2 initiative has become a synergistic working group based on very high resolution PlĂ©iades stereo images provided by CNES and potentially Copernicus Sentinel-1 and -2 data. The organization is as follows In case of events such as earthquake, volcano eruption, landslides or glacier collapse, the CIEST2 steering committee decides to activate the CIEST2 device. Then, CNES immediately triggers PlĂ©iades stereo tasking by Airbus Defense and Space Airbus DS in order to enable DEM generation or multi-temporal analysis. The acquisition strategy chosen consists of pointing the PlĂ©iades-1A and -1B satellites systematically at each passage over the area. For 10 consecutive days, daily acquisitions in "stereo" mode take place, exploiting the agility of the satellite, capable of pointing its optical system towards any target located in its field of view. Each acquisition consists of a pair of two images, taken with different viewing angles, less than a minute apart from the same orbit, in order to increase the chances of obtaining a visual, and, if applicable, to be able to calculate the topography of the area of interest by Geostationary-data-driven operational serviceHOTVOLC is a Web-GIS Geographic Information System volcano monitoring system Fig. 1 using SEVIRI Spinning Enhanced Visible and Infrared Imager sensor on-board METEOSAT geostationary satellite and developed at the OPGC Observatoire de Physique du Globe de Clermont-Ferrand in 2009 after the installation of the first receiving station. The spectral bands of the SEVIRI sensor allow the HOTVOLC system to simultaneously characterize volcanic ash, sulfur dioxide, and lava flow emissions. It is designed for the real-time monitoring of ~ 50 active volcanoes and provides high value-added products at the frequency of one image every 15 min with a pixel resolution of 3 × 3 km at nadir. HOTVOLC is open-access and data can be downloaded from the entire database covering the period 2010–2021. Satellite products are delivered in the form of i geo-referenced images geotiff tiled on a background map, and ii time series csv associated with interactive data visualization technologies. HOTVOLC is part of the SNOV and is labelled by the CNRS since 2012. Within this framework we ensure real-time monitoring of French volcanic targets, as for Piton de la Fournaise effusive eruptions Peltier et al., 2021; Thivet et al., 2020. Also, we provide timely information on other volcanic targets whose products may affect French territories such as the Icelandic 2010 Eyjafjallajökull eruption Bonadonna et al., 2011; Labazuy et al., 2012, whose volcanic ash plumes reached the French airspace. Since 2018, HOTVOLC falls under the official function of Meteo-France Gouhier et al., 2020 and provides data to the Toulouse VAAC Volcanic Ash Advisory Centre allowing a better assessment of the risk related to air traffic. Figure 1 is a screenshot of the HOTVOLC Web-GIS interface, showing the first hot spot anomaly detected by the system on March 19, at 21h15 UTC, only 30 min after the 2021 Fagradalsfjall eruption start, and which evidences the arrival of lava flows on the 1Screenshot of the HOTVOLC Web-GIS interface showing the hot spot anomalies red pixels in the Reykjanes peninsula 45 min after the onset of the eruption on March 19, 21h15 UTC. Below, one can observe a time series of the total spectral radiance spanning one month of effusive activityFull size imageMOUNTS Sentinel-Copernicus operational serviceMOUNTS Monitoring Unrest from Space, Valade et al. 2019, is an operational volcano monitoring system using the polar-orbiting ESA Copernicus Sentinel satellite constellation Sentinel-1, -2, -5P, together with Deep Learning, to assist in specific processing tasks. The synergistic use of radar Sentinel-1 Synthetic Aperture Radar SAR, short-wave infrared Sentinel-2 MultiSpectral Instrument MSI and ultraviolet Sentinel-5P TROPOMI payloads, allows for monitoring on a single web-interface of surface deformation, topographic changes, emplacement of volcanic deposits, detection of thermal anomalies, and emission of volcanic SO2. The web-design is inspired by the MIROVA volcano monitoring system Coppola et al. 2016a, b, whereby monitored products are delivered in the form of images and time series, with interactive tools added to ease the data visualization Fig. 2. The system currently monitors over 70 volcanoes worldwide, but the number is regularly increasing as its flexible design allows for rapid addition of new volcanoes in response to volcanic unrest in any part of the 2Screenshot of the MOUNTS interface showing Sentinel data images and time series in the Reykjanes peninsula at the onset of the eruptionFull size imageIn this study we will only present Sentinel-2 data from MOUNTS, here used to derive information on lava flow field emplacement. Sentinel products are automatically downloaded from the Copernicus Open Access Hub as soon as they are available typically 2–12 h from sensing for Sentinel-2 L1C products, and immediately processed and published on the MOUNTS website typically h after availability online. Sentinel-2 images are acquired from two polar-orbiting satellites Sentinel-2A and -2B, launched in 2015 and 2017 respectively, and placed 180° from each other in the same sun-synchronous orbit. The revisit time is 5-days on average reduced to 2–3 days at mid-latitudes, with spatial resolution of 20 m/pixel in the SWIR bands and 10 m/pixel in the optical dataThe data collected by PlĂ©iades during 22–31 March 2021 days 3 to 13 after the start of the eruption were tasked by Airbus DS and CNES in "emergency mode”. During this time period, the satellite imaged the area of interest daily between 1250–1330 local time, and the images were available for download about 2 h after the acquisition. Table 1 lists the characteristics of the subset of images for which the eruption site was cloud 1 Characteristics of PlĂ©iades acquisitions all in stereo mode with good visibility limited cloud cover over the eruption site and used to estimate the volume of the lava field between days 3 and 13 after the eruption startedFull size tableMapping the lava area, volume and effusion rateOnce downloaded, we processed a subset of the images using the Ames StereoPipeline ASP, Shean et al., 2016 with the correlation parameters defined by Deschamps-Berger et al., 2020. The processing pipeline included the use of a reference DEM, which constrains the matching algorithms in the photogrammetric processing. For reference, we used the IslandsDEMv0 from the National Land Survey of Iceland The IslandsDEM is a seamless 2 × 2 m DEM mosaic with improved spatial accuracy compared to the ArcticDEM Porter et al., 2018, by merging repeated ArcticDEM acquisitions in order to minimize processing time with ASP of each PlĂ©iades stereopair was 200 °C ca., with an overall estimate of 2 – 4% false alerts detected Massimetti et al., 2020. The reliability of the applied algorithm has already been successfully tested, firstly with a direct comparison to volcanogenic heat flux in Watt through MODIS Middle Infrared images; and then on a variety of different volcanological thermal-emitting phenomena worldwide, such as strombolian and effusive eruptions Laiolo et al., 2019, open-vent and lava lakes Massimetti et al., 2020 and explosive lava dome behavior Shevchenko et al., 2021. The algorithm used here is currently part of two online, automated, near-real time and global volcanic monitoring systems the MIROVA thermal monitoring system based on MODIS MIR data, Coppola et al., 2016a, b, and the multiparametric MOUNTS project presented above; Valade et al., 2019, and was the first SWIR Sentinel-2 thermal algorithm operationally online and publicly available Massimetti et al., 2020.Results and DiscussionPlĂ©iadesLava flow field characterizationFigure 3 is an example of a multispectral image left panel derived from the PlĂ©iades stereo-images acquired on the 30th of March. It shows the lava flow footprint with hot spots in red color located at the center of the lava flow unit, and cooled areas in black around it. On the right panel, we provide the lava thickness map with volume of magma emitted and surface footprint. 11 days after the eruption start, the active center part of the lava flow reaches a maximum thickness of 35 m, for a surface of km2, leading to a lava volume of Mm3 at this time point of magma emitted. This information was provided to the Icelandic Civil Protection about 6 h after the image 3Left panel PlĂ©iades multispectral image acquired on the 30th of March 2021, Right Panel lava thickness derived by differentiating the DEM produced in response mode from the images acquired on the 30th of March 2021 and the pre-eruptive arctic DEM. Background hillshade of the 30th March DEM. © CNES 2021, Distribution Airbus DSFull size imageAll successive volumes and effusion rates 22, 23, 26, 29, 30, and 31 March estimated in the response mode either from PlĂ©iades images or airborne surveys are listed in Table 2 together with those estimated by reanalysis and represented in Fig. 4. Reanalysis data are very close to the ones of the response mode showing the robustness of operational routines used which is essential for rapid and reliable response of the Civil Protection Authorities. The data presented demonstrate that the cumulative volume Fig. 4 increases almost linearly with time having a lava effusion rate ranging from 5–6 m3/s. In more details, the accuracy of PlĂ©iades data allows us to witness a small but significant decrease of the lava effusion rate from m3/s on the 22nd of March to m3/s on the 30th of March Fig. 4. Interestingly, the two lava volumes provided by airborne data are in very good agreement with the PlĂ©iades results. Indeed, lava volumes derived from airborne data on 22/03 1010UTC is Mm3 while the PlĂ©iades one, ~3 hours later 1315UTC on the same day, is Mm3. Airborne results, seen here as ground truth, demonstrate the accuracy of PlĂ©iades data, and reinforce the objective of the CIEST2 initiative as using PlĂ©iades images for operational purposes. Figure 5 presents all the thickness maps derived from PlĂ©iades data in the reanalysis mode. From Table 2 and Fig. 4, it appears here again that there is no significant difference between volumes estimated in response mode and those estimated afterwards during the reanalysis differences are within error bars. We can thus conclude that the response mode was efficient at providing a quick and rather accurate estimation to the Icelandic Civil Protection. For the airborne survey, the reanalysis slightly modified the estimation of volume derived from the survey performed on the 23rd of March whereas it didn’t change significantly the estimation derived from the one made on the 31st of March. The thickness distribution agreement derived from PlĂ©iades images and the airborne survey has been tested as a thickness difference map Fig. 6 on 23 March, where the PlĂ©iades acquisition was performed 3 h only after the airborne survey. The result is important, as no significant elevation difference remains overall, except at the location of the active vents of lava emission, where effusion rates are high enough to build a detectable change in lava flow elevation in about 3 2 Total lava volumes calculated from PlĂ©iades and airborne stereoimages, in response-mode and reanalysis-mode, using the Islands DEM as the pre-eruption DEM. Volumes are expressed in million cubic meters. All the effusion rates are reported as an average since the start of the eruption, defined on 19 Mar 2021, 2140 local timeFull size tableFig. 4Lava volume and effusion rate average since the start of the eruption calculated in response mode and in reanalysis modeFull size imageFig. 5Lava thickness maps obtained after reanalysis for the 5 PlĂ©iades acquisitions listed in Table 2. Background PlĂ©iades orthorectified images. © CNES 2021, Distribution Airbus DSFull size imageFig. 6Difference in elevation between the two surveys from 23 March PlĂ©iades and airborne DEMs, in reanalysis mode. Red colors indicate thickening, as in the NW lobes of the eruptionFull size imageVolcanic plume characterizationVolcanic plume altitude estimation is essential as it provides information on eruption source parameters and dynamics, and is essential for air traffic risks mitigation. In this regard, the Plume Elevation Model PEM as calculated from PlĂ©iades is very accurate and can be reliably used. In Fig. 7, we presents the results of the PEM from a volcanic cloud imaged on the 23rd of March 2021 by PlĂ©iades. The altitude of the volcanic cloud varies between 300 and 800 m above sea level. This is a weak buoyant plume, mostly composed of condensed water, and probably sulfuric acid droplets with little or no ash Barnie et al., 2022. The trajectory of such a volcanic plume is fully controlled by the wind. The maximum velocity of the volcanic plume displacement reaches 14 m/s, which is in accordance with observations made with the Global Forecast System GFS by National Oceanic and Atmospheric administration NOAA, visualized with Ventusky web platform 7Plume Elevation Model of Fagradalsfjall, results from the 23rd of March 2021 top PlĂ©iades image, panchromatic band; middle produced elevation map; bottom produced velocity map. PlĂ©iades images courtesy of CNES via CIEST2, © CNES 2021, Distribution Airbus DSFull size imageMeteosat-SEVIRIAs a geostationary platform, the MSG-SEVIRI satellite allows rapid detection of lava hot spots as well as the estimation of quantitative parameters such as lava volume and lava effusion rates. This operational effort is currently being carried out by the HOTVOLC web-service, especially for Icelandic targets where volcanic eruptions are frequent. Therefore, results presented here directly come from data of the HOTVOLC platform, in crisis response mode, and no offline processing has been carried out for this particular case. This fills the main objective of the paper, that is, to show how satellite data can assist rapid decision making and response with online data using operational Fig. 8, we show a time series of the lava Volume Flow Rate VFR in m3/s for the first 10 days of the eruption, associated with the cumulative lava volume over the same period. The first detection occurred at 21h15 UTC on 19 March with a VFR of m3/s, that is, less than one hour after the eruption start. The related hot spot detection is visible in real-time on the HOTVOLC interface, and associated with a color code scaled to the spectral radiance amplitude. Detections were scarce during the following two days likely due to the presence of a volcanic plume above the source vents. Then, the rate of acquisition improves to one image every 15 min and shows an increase of the VFR up to 20–30 m3/s around 23 March. Then, the VFR decreases to values in the range 5–10 m3/s for the rest of the period with some peaks at around 15 m3/s. The time evolution of the VFR can also be read through the cumulative lava volume slope, first increasing, and then decreasing. On March 30, the total volume emitted and estimated using MSG-SEVIRI is ~ Mm3, and corresponding to an average effusion rate over the ten days of m3/s. In Fig. 8, we also compare cumulative lava volume from MSG-SEVIRI, PlĂ©iades and airborne data. Related volumes estimations are quite close and show a similar time evolution, with all values derived from MSG-SEVIRI being slightly larger than the ones derived from other methods. All results are summarized in Table 3 in the conclusion 8time series of the instantaneous lava Volume Flow Rate VFR in m3/s and cumulative lava volume m3 during the first 10 days of the eruption, with landmarks showing acquisition times of PlĂ©iades imagesFull size imageTable 3 Summary of the quantitative information on the lava flow evolution provided by the various independent remote sensing datasets considered in this studyFull size tableSentinel-2Here we present Sentinel-2 MSI images S2 hereafter processed by MOUNTS, with the aim to show the contribution of these products having an intermediate spatial and temporal resolution with respect to PlĂ©iades and Meteosat products. As the effusive eruption began on 19 March from a ~ 150 m long fissure inside the Geldingadalir valley, and evolved to a larger crater with two main vents, the spatial resolution of S2 products is appropriate to map and observe the evolution of the lava field. We show the first two cloud-free images, depicting the first stage of the eruption, acquired on the 23rd of March 2021 1302 UTC and the 30th of March 2021 1312 UTC. Other S2 images were acquired on March 25 and 28. However the thick and pervasive cloud coverage does not allow proper visualization of the evolving lava field. The images are presented in Fig. 9, with three different visualizations i 10x10 km image with a combination of optical bands and SWIR bands, highlighting the presence of hot materials over background and to appreciate the surrounding environmental features; ii a 2x2 km zoom with a combination of optical and SWIR bands, only for the pixel detected by the algorithm as hot; iii a 2x2 km side zoom solely with the SWIR 9Cloud-free Sentinel-2 images acquired during the first 10 days of the eruption. Left panel is a 10x10 km image with a combination of optical bands and SWIR bands "hot" pixel detected by the algorithm are displayed using the SWIR bands, middle panel is a 2x2 km zoom, right panel is a 2x2 km zoom with solely SWIR band combinationFull size imageThe hot spot algorithm automatically detected on 23 March a total of 920 hot pixels, and on 30 March a total of 686 pixels. These can be converted into “hot” area by multiplying by the pixel area 20X20 m2 of the Sentinel 2 SWIR bands. The converted area thus resulted in km2 and km2 for 23 March and 30 March, two S2 images, acquired 7 days apart, allow monitoring of the lava flow field evolution. The first image shows a single and unique thermal anomaly expanding around the main eruptive fissure, while the second presents an already partially evolved lava area, with some portions already cooled and crusted NNW, a portion still hot and active around the main vents, and the first stage of lava flow moving towards the described in Massimetti et al. 2020 and visible in Fig. 9, the number of hot pixels detected over highly radiative bodies such as lava flows can sometimes be overestimated, in particular due to halo effects and artifacts on the MSI detector diffraction spikes triggered by instrument optics effects and intense thermal emissions, particularly visible on the March 23 acquisition. Nevertheless, the lava flow area estimated by S2 seems in good agreement with PlĂ©iades image acquired on the 30th of March 2021 see Fig. 3, with a final estimate of first part of the ongoing effusive eruption at Fagradalsfjall on Reykjanes Peninsula, Iceland that began March 19, 2021, was closely monitored in near-real time by photogrammetry using high-resolution optical PlĂ©iades stereo images. Key information such as the lava flow outlines, thickness maps, volumes and average effusion rates were provided to the civil protection in less than 6 h after the data acquisition, which was useful for hazard evaluation, aided in the development of scenarios on potential impact on infrastructure, and helped to manage tourism resulting from this spectacular eruption not far from of the Icelandic capital our knowledge, this is the first time that stereo High Resolution optical satellite data are used in an operational way for eruption monitoring. The absence of prior usage for hazard monitoring is probably linked to non-systematic availability of these datasets. For the Fagradalsfjall eruption, PlĂ©iades acquisitions were available, during the first ten days of the event, thanks to a special tasking request made to Airbus DS by CNES after the CIEST2 activation. We benefited from a favorable situation where the eruptive event had been anticipated and weather conditions during this period were quite good. The systematic acquisitions over the eruption site lasted for 10 days but additional stereo PlĂ©iades images have been acquired subsequently 28th of April and 2nd of July by the Icelandic Volcanoes Supersite project supported by the Committee on Earth Observing Satellites or by commercial the subsequent reanalysis of the results produced initially in an operational way and the comparison with area, thickness, volume, and effusion rates derived from airborne surveys validate the near-real time estimations obtained in “response mode” and rapidly provided to local authorities for crisis management. In addition, PlĂ©iades images have the potential to provide useful complementary information on the state of the volcanic plume elevation and velocity. For the response mode, we relied on local processing chains, quickly adjusting off-the-shelf tools. Indeed, operational monitoring platforms for volcanic activity like MOUNTS or HOTVOLC usually takes advantage of systematic and freely distributed satellite acquisitions. In this study, by comparing the lava flow area and effusion rate estimations derived from PlĂ©iades images with, respectively, the area and effusion rates obtained from respectively Sentinel-2 data and from MSG-SEVIRI data, we confirmed the potential of these open-access platforms to quantitatively provide robust real-time information for effusive eruption monitoring see Table 3 for a summary of results obtained by various independent methods.The eruption of Fagradalsfjall 2021 is a proof of concept of the added value of satellite data for volcano monitoring. It shows that despite the strong potential of routinely acquired satellite data Copernicus, MSG and their efficient exploitation via online and open access platforms, access and availability of high resolution data such as PlĂ©iades imagery can be of major importance in developing operational processing chains dedicated to these particular data. In this perspective, the DSM-OPT online service of ForMter operated by EOST has been improved to automatically produce DEMs from PlĂ©iades stereo images as soon as they are delivered by Airbus DS after activation by CIEST2. Since the Icelandic eruption, CIEST2 has also enabled PlĂ©iades acquisition for the St Vincent SoufriĂšre eruption in April 2021 and for the Nyiragongo eruption in May 2021. Availability of data and materials The datasets used and/or analyzed during the current study are available from the corresponding author on. reasonable request. ReferencesPorter, C., Morin, P., Howat, I., et al. ArcticDEM. 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VP was supported by the CNES project MagmaTrack. We also thank the handling editor for helpful data processing associated with SV’s work was funded thanks to the PAPIIT project informationAuthors and AffiliationsUniversitĂ© Clermont Auvergne, CNRS, F-63000, Clermont-Ferrand, IRD, OPGC, LMV, FranceMathieu Gouhier & Yannick GuĂ©henneuxVirginie Pinel- University Grenoble Alpes, University Savoie Mont Blanc, CNRS, UGE, ISTerre, Grenoble, IRD, FranceVirginie PinelNational Land Survey of Iceland, Akranes, IcelandJoaquĂ­n M. C. BelartInstitute of Earth Sciences, University of Iceland, ReykjavĂ­k, IcelandJoaquĂ­n M. C. Belart & Magnus Tumi GudmundssonBRGM, Risks and Prevention Department, Geophysical Imagery and Remote Sensing Unit, 3 avenue Claude Guillemin, 45060, OrlĂ©ans, FranceMarcello De Michele & Daniel RaucoulesCNES Centre National d’Études Spatiales, Toulouse, FranceCatherine Proy & Claire TinelLEGOS UniversitĂ© de Toulouse, CNES, CNRS, UPS, Toulouse, IRD, FranceEtienne BerthierIcelandic Institute of Natural History,, GarabĂŠr, IcelandBirgir V. ÓskarssonUniversity Grenoble Alpes, University Savoie Mont Blanc, CNRS, UGE, ISTerre, Grenoble, IRD, FranceShan GremionDepartamento de VulcanologĂ­a, Instituto de GeofĂ­sica, Universidad Nacional AutĂłnoma de MĂ©xico UNAM, Mexico City, MexicoSĂ©bastien ValadeDepartment of Earth Sciences, University of Torino, Via Valperga Caluso 35, 10125, Turino, ItalyFrancesco MassimettiDepartment of Civil Protection and Emergency Management, National Commissioner of the Icelandic Police, ReykjavĂ­k, IcelandBjorn OddssonAuthorsMathieu GouhierYou can also search for this author in PubMed Google ScholarVirginie PinelYou can also search for this author in PubMed Google ScholarJoaquĂ­n M. C. BelartYou can also search for this author in PubMed Google ScholarMarcello De MicheleYou can also search for this author in PubMed Google ScholarCatherine ProyYou can also search for this author in PubMed Google ScholarClaire TinelYou can also search for this author in PubMed Google ScholarEtienne BerthierYou can also search for this author in PubMed Google ScholarYannick GuĂ©henneuxYou can also search for this author in PubMed Google ScholarMagnus Tumi GudmundssonYou can also search for this author in PubMed Google ScholarShan GremionYou can also search for this author in PubMed Google ScholarDaniel RaucoulesYou can also search for this author in PubMed Google ScholarSĂ©bastien ValadeYou can also search for this author in PubMed Google ScholarFrancesco MassimettiYou can also search for this author in PubMed Google ScholarBjorn OddssonYou can also search for this author in PubMed Google ScholarContributionsMG designed the paper and planned the research. VP, SG, JB and EB processed PlĂ©iades data for lava volume and effusion rates. MdM and DR processed PlĂ©iades data for volcanic plume study. CP and CT helped with fast PlĂ©iades acquisition through the CIEST2 consortium. MG and YG processed IR data from HOTVOLC platform MSG-SEVIRI. MTG, BO and BO led the operational survey for airborne data acquisition and processing. SV and FM processed sentinel-2 authorCorrespondence to Mathieu declarations Competing interest The authors declare that they have no competing interests. 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To view a copy of this licence, visit The Creative Commons Public Domain Dedication waiver applies to the data made available in this article, unless otherwise stated in a credit line to the data. Reprints and PermissionsAbout this articleCite this articleGouhier, M., Pinel, V., Belart, et al. CNES-ESA satellite contribution to the operational monitoring of volcanic activity The 2021 Icelandic eruption of Mt. Fagradalsfjall. J Appl. Volcanol. 11, 10 2022. citationReceived 17 September 2021Accepted 11 July 2022Published 13 August 2022DOI sensingPlĂ©iades imagesInfrared monitoringLava Unitinerario che unisce un self drive nella prorompente e lussureggiante isola di RĂ©union ad un rilassante soggiorno mare nella dolce isola di Mauritius. Due isole cosĂŹ vicine ma con paesaggi e culture completamente differenti, entrambe avvolte dalla calda luce dei Tropici.
Loading video... Appears in Newsflare picks 0133 Uploading since 13th May 2018 Want to talk to someone about licensing? Source file resolution 720p Filmed on Friday 25th October 2019 Unnamed Road, RĂ©union The volcano Piton de la Fournaise erupted on the island of La RĂ©union on October 25, with streams of lava running down the mountainside in this incredible video. The eruption was the fifth of the active volcano this year, with onlookers filming the destructive event from nearby hills on the tropical island. From the blog Celebratory Days and Key Events – From weird, wild, and heart-warming videos to the most shocking clips that will make your jaw drop! User-generated video UGV is shaping your audiences, whether you realise it or not. Polished, professionally produced videos don’t go viral anymore. It’s the stories and experiences users create and share on video-centric platforms such as Snapchat, Instagram and TikTok that now generate the most views, likes and shares. UGV is no longer the colour or the supporting content; it’s setting the agenda and leading the coverage - breaking news and providing first-on-the-scene footage, telling immersive stories, and entertaining audiences as they scroll through their feeds. Why? Because the value of UGV lies in its ability to immerse us in real events, stimulate emotional responses, deliver richer experiences, and indulge our growing need to feel more connected to the moments that matter. View post Related videos Uploading since 13th May 2018 Want to talk to someone about licensing?
CAMÉRASEN DIRECT DU VOLCAN Unique, sublime, totalement dĂ©paysant et culminant Ă  2 632 mĂštres d'altitude, le Volcan du piton de la Fournaise Ă  l'Ăźle de La
Par Emma Vlog Trotter ROAD TRIP À LA RÉUNIONS’il y en a bien un Ă  ne pas louper, c’est lui, l’emblĂšme de La RĂ©union le Piton de la volcan toujours actif, qui offre aux RĂ©unionnais et aux touristes chanceux, un spectacle hallucinant lorsqu’il entre en Ă©ruption. En effet, c’est un volcan effusif, qui n’est donc absolument pas dangereux mĂȘme s’il est sous haute soit au repos ou en train de pĂ©ter» comme on dit sur l'Ăźle intense, le spectacle naturel de ce volcan et de son parc, classĂ© au Patrimoine Mondial de l’UNESCO est de toute splendeur. C’est incontestablement le n°1 des incontournables lors d’une visite Ă  La classement ci-dessous correspond au parcours initiatique qui vous mĂšnera, Ă©tape aprĂšs Ă©tape, au coeur du Piton de la Fournaise01 La route des Laves & le Grand BrĂ»lĂ©02 Les Hautes-Plaines & Bourg-Murat03 La route du volcan du cratĂšre Commerson Ă  la Plaine des Sables 04 Randonner au coeur du volcan05 Le Piton de la Fournaise en Ă©ruption comment approcher la bĂȘte !Mais le volcan se mĂ©rite, il se dĂ©voilera Ă  vous aprĂšs un parcours quasi initiatique, au cours duquel vous verrez le paysage changer, passer d’une forĂȘt de cryptomĂ©rias Ă  un paysage absolument lunaire et grandiose, pour finalement atteindre le Pas de Bellecombe et approcher au plus prĂšs la majestueuse filmĂ© toute la route et tous les Ă©lĂ©ments incontournables dont je vous parle exceptĂ© Bourg-Murat dans mon VLOG ci-dessus Le Piton de la FOURNAISE». Et pour vous faire une confidence, je suis tombĂ©e raide dingue de ce volcan depuis que j’ai eu la chance de l’approcher en pleine la route des laves !Vous pouvez dĂ©marrer l'approche de la Fournaise par la dĂ©couverte du versan Sud du volcan et l'impressionnante Route des Laves. Indissociable du Volcan, on peut observer les coulĂ©es de laves sĂ©chĂ©es qui se jettent dans l'OcĂ©an sur la fameuse route du Grand BrĂ»lĂ©. Une trĂšs bonne mise en bouche pour dĂ©couvrir le superbe cĂŽne de la Fournaise qui trĂŽne en arriĂšre plan. 02 LES HAUTES PLAINES & BOURG-MURAT 1ÈRE ÉTAPELe petit village de Bourg-Murat, tout dernier rempart avant d’emprunter la route du volcan. À vrai dire, pas grand-chose Ă  faire ici, car Bourg-Murat est surtout une escale oĂč dormir pour dĂ©couvrir le volcan de trĂšs bonne heure. Toutefois, si vous arrivez dans la journĂ©e, vous pourrez visiter la CitĂ© du Volcan, un musĂ©e assez complet qui vous en apprendra plus sur la bĂȘte avant de partir Ă  sa rencontre. ATTENTION Ă  LA BRUME qui peut recouvrir le cratĂšre du VOLCAN !Comme dans les Cirques, la brume peut s’installer en matinĂ©e et recouvrir totalement le cratĂšre du volcan. C’est une chose frĂ©quente, mais une fois que l’on est averti, on anticipe et on s’arrange pour arriver avant elle. Je vous recommande donc de passer la nuit Ă  Bourg-Murat, afin de prendre la route Ă  05h30 le lendemain matin compter une bonne heure de route jusqu’au volcan afin d’ĂȘtre sur place pour le lever du soleil. Ainsi, vous mettrez toutes les chances de votre cĂŽtĂ© de pouvoir profiter dela Plaine des Sables aka On a marchĂ© sur la lune» pour quasiment vous tout seul, ainsi que le Piton de la Fournaise, parfaitement N’oublions pas que ce n’est pas une science exacte, et que la Nature seule dĂ©cidera de ce qu’elle vous dĂ©voilera le jour de votre visite et peut-ĂȘtre choisira -t'elle exceptionnellement d’ĂȘtre couverte de brume tĂŽt le matin, mais de maniĂšre globale, c’est Ă  mon sens ce qu’il y a de mieux Ă  faire pour mettre toutes les chances de votre cĂŽtĂ©. N’hĂ©sitez pas Ă  me dire en commentaire si vous avez suivi mon conseil et si ça a marchĂ©! ;OÙ DORMIR & OÙ MANGER À BOURG-MURAT ?GÎTE Chez ClĂ©ment ALICALAPA-TENON 154, chemin du Champ de Foire Ă  Bourg-Murat - TĂ©l 06 92 08 80 09Chambre double Ă  50€ petit dĂ©jeuner inclus. Repas complet apĂ©ro, entrĂ©e, plat & dessert 20€ par personne. J’y ai sĂ©journĂ© Ă  deux reprises avant de me rendre au volcan et c’est top les chambres sont super mignonnes, la literie est excellente, et l’accueil trĂšs chaleureux, tout est impeccable. DÎNER À L'AUBERGE DU VOLCAN 194, rue Maurice et Katia KRAFT - 27Ăšme km BOURG-MURAT - TĂ©l 02 62 27 50 91 Si vous prĂ©fĂ©rez sortir et vous promener dans Bourg-Murat, je vous recommande l’Auberge du Volcan. Leur carte trĂšs complĂšte propose toutes les spĂ©cialitĂ©s locales et c’est tout bonnement la route du volcan, le parcours intiatique !On dit que le plus beau dans un voyage n’est pas forcĂ©ment l'arrivĂ©e, mais la route qui nous mĂšne Ă  notre but. VoilĂ  un adage qui se vĂ©rifie totalement lorsqu’on emprunte la route fascinante qui nous conduit au Piton de la ÉTAPE LE CRATERE COMMERSON La route du volcan est un spectacle en soi le paysage change tous les 5 quittant Bourg-Murat, on commence par traverser une forĂȘt de cryptomerias qui peu Ă  peu s’estompe pour laisser place Ă  un pare-terre d’arbustes. C’est alors qu’on s’arrĂȘte impĂ©rativement! au BelvĂ©dĂšre du CratĂšre Commerson pour admirer le premier cratĂšre qui s’offre Ă  nous. 20 km plus loin, les arbustes disparaissent totalement laissant place Ă  un paysage lunaire PLAINE DES SABLESLE PAYSAGE de La RĂ©union c’est lui, celui de la Plaine des Sables. S’il ne devait en rester qu’un, ce serait dĂ©finitivement une heure ou deux minimum d’arrĂȘt avec de la crĂšme solaire, car quand vous aurez dĂ©couvert cet endroit, vous n’aurez plus du tout envie d’en repartir. Au dĂ©tour d’un virage sur la route qui nous conduit au volcan, se dĂ©couvre subitement en contrebas, cet endroit surrĂ©aliste. On est immĂ©diatement saisi parla beautĂ© et la magnificence du lieu. Et surtout, on n'a jamais vu un tel endroit de sa vie!On a l’impression d’ĂȘtre un cosmonaute qui dĂ©barque sur la planĂšte Mars ou sur la Lune. DĂ©sert rocailleux, silence Ă©crasant, chaleur, roches rouges et lave sĂ©chĂ©e sur des centaines de mĂštres Ă  la ronde, et tout ça, cernĂ© par les parois d’un ancien cratĂšre
 VoilĂ  le dĂ©cor
Frissons garantis! Attention au coup de bambou, le soleil cogne fort sur Mars, et mĂȘme si on ne s'en rend pas compte sur le moment, on peut rapidement cramer. Tartinez-vous de protection solaire pour Ă©viter de quitter la plaine des Sables le visage aussi cramoisi que les cet endroit trĂšs prĂ©cisĂ©ment, nous sommes entrĂ©s sur le territoire du volcan. L’excitation se transforme en contemplation et en respect incommensurable face Ă  la puissance de la nature. On gare sa voiture, et tout petit que l'on se sent, on part fouler la terre de cette improbable Plaine des Sables. LE GITE DU VOLCANAprĂšs avoir fait le plein de PlanĂšte Mars et ça repart !, on remonte en voiture en sachant qu’heureusement, on repassera Ă  nouveau par cet endroit de toute beautĂ© pour repartir et qu’on pourra donc s’y arrĂȘter une seconde fois ouf !. On se dirige Ă  prĂ©sent vers le volcan qui n’est plus trĂšs loin
 Deux solutions s’offrent Ă  vous Faire l’aller-retour dans la journĂ©e pour ceux qui manqueraient de temps, et ce sera dĂ©jĂ  la nuit au GĂźte du Volcan pour randonner dans le Parc Naturel tĂŽt le lendemain GĂźte du Volcan est le seul Ă©tablissement que vous trouverez entre Bourg-Murat et la Fournaise. Il est ouvert toute la journĂ©e et propose des boissons, sandwichs et repas le midi aux visiteurs de passage. Mas surtout, il est construit Ă  flanc de falaise sur un cratĂšre et se trouve juste Ă  cĂŽtĂ© du Pas de Bellecombe, qui est le point de vue final de contemplation du volcan, et le dĂ©part de nombreuses randonnĂ©es dans la un GĂźte charmant et trĂšs bien entretenu, qui propose des nuitĂ©es en dortoir ainsi que le repas du soir excellent et trĂšs copieux ! pour les randonneurs. LE GÎTE DU VOLCAN - Route du Volcan 600m avant le Pas de Bellecombe TĂ©l +262 692 85 20 91 Tarif 16€ par personne. Nuits en dortoir uniquement - Repas du soir 20€04 Ă  l'assaut du merveilleux piton de la fournaise !RANDONNER AU coeur DU VOLCANPlusieurs randonnĂ©es s’offrent Ă  vous, de durĂ©es et de niveaux de difficultĂ©s variables, mais toutes d’une splendeur rare. Le point de dĂ©part des randonnĂ©es que je vous conseille est le Pas de Bellecombe, Ă  savoir le bout du bout de la route du volcan photo ci-dessusÀ cet endroit prĂ©cis, vous avez un belvĂ©dĂšre qui domine l’enclos», le cratĂšre principal du volcan. Vous apercevrez presque en dessous de vous le petit Formica LĂ©o, un minuscule et adorable petit piton, Ă  cĂŽtĂ© duquel on peut se promener en descendant dans l’ sur le cratĂšre Rivals AprĂšs ĂȘtre descendu dans l’enclos, vous avez la possibilitĂ© de poursuivre votre marche jusqu’au cratĂšre Rivals. RandonnĂ©e sans grande dans l'enclos jusqu'au Formica LĂ©o RandonnĂ©e familiale sans grande difficultĂ©, Ă  travers laquelle on se promĂšne dans l’enclos. Photo du Formica LĂ©o ci-dessusRandonnĂ©e du sentier du Dolmieu Cette randonnĂ©e qui grimpe pas mal vous conduira au sommet du cratĂšre Ă  2 350m d’altitude. La randonnĂ©e est physique mais exceptionnelle. Compter la journĂ©e, environ 7h aller-retour depuis le Pas de Bellecombe. Il sera indispensable de partir tĂŽt le matin et prĂ©voir son pique-nique et beaucoup d’ vers le Piton de Bert Le dĂ©part de cette randonnĂ©e s’effectue depuis le parking Foc Foc, non loin du Pas de Bellecombe. Compter 2h30 aller-retour et aucune difficultĂ© puisque tout le sentier est en plat. On longe la crĂȘte de l’enclos, avec une vue plongeante sur ce dernier et sur le Piton de la Fournaise. C’est une trĂšs belle randonnĂ©e que j’ai eu la chance de faire de nuit pour assister Ă  l’éruption d’octobre 2018 du Piton de la Fournaise
05 randonner au piton de la fournaise... lors d'une Ă©ruption !On prĂ©voit souvent un voyage plusieurs mois Ă  l’avance, c’est donc le hasard absolu de tomber pile au moment d’une Ă©ruption. J’ai eu beaucoup de chance lors de mon voyage Ă  la RĂ©union, car aprĂšs avoir pu nager avec les baleines et couvrirle Grand Raid, je suis arrivĂ©e sur l'Ăźle pile lors d'une Ă©ruption du majestueux Piton de la d’une Ă©ruption, les sentiers de randonnĂ©es qui passent pas l’enclos sont fermĂ©s au public pour des raisons Ă©videntes de sĂ©curitĂ©. Mais il y a tellement de pitons autour de la Fournaise, qu’il y a aura toujours un sentier que vous pourrez emprunter pour avoir un point de vue sur les coulĂ©es de Ă©ruption est diffĂ©rente et ne se manifeste pas de la mĂȘme maniĂšre, ni au mĂȘme endroit. Lors de ma venue Ă  La RĂ©union en octobre 2018, c’est via le sentier du Piton de Bert que j’ai pu observer l’éruption de nuit, histoire d’en prendre encore plus plein les lors de votre venue vous avez la chance de pouvoir assister Ă  une Ă©ruption du Piton de la Fournaise, n’hĂ©sitez pas Ă  tĂ©lĂ©phoner Ă  l’Office du Tourisme du Tampon je ne veux pas entendre la moindre blague...! qui saura vous aiguiller sur le sentier Ă  emprunter pour avoir un point de vue sur l’éruption. Ils sont adorables et ont l’habitude de conseiller les randonneurs. Si vous rencontrez malgrĂ© tout des difficultĂ©s Ă  trouver les bonnes infos, Ă©crivez-moi et je tĂącherai de vous aiguiller au mieux, car c’est Ă  ne pas rater;Pour prĂ©parer ma double randonnĂ©e nocturne & lever du soleil au Piton de Bert, je dĂ©cide de passer la nuit au GĂźte du volcan, oĂč j'ai motivĂ© un petit groupe de randonneurs pour venir avec moi voir les coulĂ©es de DĂ©collage du GĂźte du Volcan en voiture direction le Parking Foc Foc 15 minutes03h30 DĂ©but de la randonnĂ©e de nuit vers le Piton de vite la magie opĂšre. On aperçoit au loin une nuĂ©e rouge qui Ă©claire la nuit. Plus on avance et plus le vent froid porte un souffle chaud jusqu’à nos visages. La lumiĂšre rouge s’intensifie jusqu’au moment oĂč l’on distingue au loin le magma !À partir de lĂ , on est comme dans un rĂȘve, on avance frĂ©nĂ©tiquement, happĂ© par la promesse de ce spectacle grandiose sur la lave qui nous attire, jusqu’à atteindre le point final, celui Ă  partir duquel nous avons la meilleure visibilitĂ© sur les coulĂ©es de laves en contrebas. 05h00 ArrivĂ©e au point d’observation. 30 Ă  45 min d’observation Lever du DĂ©but de la 2Ăšme randonnĂ©e. Retour vers le Parking Foc Foc, Ă  la diffĂ©rence prĂšs que le chemin du retour s’effectue de jour et que l’on dĂ©couvre alors le chemin parcouru de nuit et la vue fantastique que l’on a sur l’enclos et sur le Piton qui continue de cracher sa Retour au Parking Foc Foc et direction le GĂźte du volcan pour prendre le petit !Lorsqu’on randonne de nuit ou tĂŽt le matin, il fait trĂšs froid mĂȘme si on est en plein cƓur de l’OcĂ©an Indien! PrĂ©voir des pulls, une doudoune le cas Ă©chĂ©ant, un bonnet et des gants. Ainsi que de l’eau en quantitĂ© et des gĂąteaux. Et bien entendu, prĂ©voir impĂ©rativement une carte de l’IGN ! Cela arrive que des randonneurs se perdent au volcan, vous n’avez pas envie d’ĂȘtre celui ou celle qui mobilisera les pompiers plusieurs heures pour partir Ă  votre recherche ?en conclusion !Le Parc Naturel du Piton de la Fournaise, est selon moi, le spot le plus impressionnant de La RĂ©union. C’est celui qui normalement, vous marquera le plus. Je vous conseille de lui consacrer au moins deux jours si votre emploi du temps le permet. Si vous avez des questions, laissez-moi un commentaire en bas de cet article, je me ferai une joie de vous rĂ©pondre, car pour vous faire une confidence, je suis devenue accro Ă  La Fournaise depuis que j'ai eu la chance de l'approcher en pleine sillonnĂ© La RĂ©union dans le cadre d'un road trip de 3 semaines Ă  travers l' rĂ©alisĂ© en collaboration avec l'IRT l'Ile de la RĂ©union en dĂ©couvrir davantage sur La RĂ©union N'oubliez pas de regarder mon VLOG consacrĂ© au Piton de la Fournaise et Ă  l'Ă©ruption !Si vous avez des questions, des souvenirs Ă  partager, ou des retours de voyages, laissez-moi un message en commentaire ! Je serai ravie de lire tout ça et je vous rĂ©ponds au plus vite À trĂšs vite pour de nouvelles aventures !

Lobservatoire volcanologique du piton de la fournaise était en reconnaissance aérienne au volcan ce matin. Le débit de lave reste relativement faible, un peu moins de 5 mÚtres cubes par

Par Robert Kassous le Ă  11h33, mis Ă  jour le Ă  11h33 Lecture 2 min. Le spectacle qu'offre le Piton de la Fournaise en Ă©ruption pourrait relancer le tourisme de l'Ăźle de la RĂ©union. Piton de la Fournaise SĂ©bastien Conejero Selon les spĂ©cialistes, le Piton de la Fournaise est l’un des volcans les plus actifs du monde par sa frĂ©quence d’éruptions en moyenne une tous les neuf mois. AprĂšs un premier Ă©pisode d’une dizaine de jours survenu en fĂ©vrier dernier, ce nouveau rĂ©veil semble s’ĂȘtre installĂ© pour durer, il pourrait ĂȘtre en intense activitĂ© durant plusieurs semaines’ indique un scientifique de l’Observatoire Volcanologique, construit sur l’üle en 1979 pour la surveillance du monstre. Volcan sous contrĂŽle Le dispositif Orsec spĂ©cifique aux volcans a Ă©tĂ© dĂ©clenchĂ© pour la protection des biens et des personnes. Pour l’instant, selon les autoritĂ©s, aucune coulĂ©e de lave rougeoyante ne menace les habitations. Elles offrent, bien au contraire, un spectacle extraordinaire et grandiose, de jour comme de nuit, Ă  des milliers d’admirateurs postĂ©s Ă  diffĂ©rents points de vue de l’üle. Il existe deux accĂšs pour admirer le spectacle route du Volcan et la route des Laves, permettant sans se mettre en danger de contempler le volcan et ses coulĂ©es. Un volcan pour doper le tourisme. En reprenant du service, le volcan dope le tourisme sur l’üle. De nombreux chasseurs de lave et de belles images, attirĂ©s par l’ampleur du monstre, affluent comme des milliers de curieux, le long de la "route des laves", ce qui provoque, Ă  certaines heures de la journĂ©e, d’énormes embouteillages. Plusieurs tours opĂ©rateurs se sont spĂ©cialisĂ©s dans l’organisation de voyages dĂ©couvertes des volcans du monde. "En organisant des expĂ©ditions je rĂ©ponds Ă  l’irrĂ©pressible besoin d’y aller voir de plus prĂšs, de se mettre au diapason de la Terre et de sa lourde respiration, de sentir sur sa nuque l’haleine brĂ»lante du monstre et de plisser les yeux devant la beautĂ© du Diable", explique poĂ©tiquement, Guy de Saint-Cyr, volcanologue et organisateur d’expĂ©dition pour Aventure et Volcans. L’office de tourisme de la rĂ©union se rĂ©jouit de cet engouement et constate que les hĂŽtels refont actuellement le plein. Une bonne nouvelle pour l’économie touristique de l’üle permettant par la mĂȘme d’oublier les attaques de requins. France La RĂ©union Bourse Le 19/08 Ă  18H05 CAC 40 6495,83 -0,94%
Lesinstruments de surveillance au Piton de la Fournaise. Auteurs: Jean Batiste Feriot, Thomas Staudacher, Louis Philippe Ricard. Cliquer le lien Les instruments de surveillance au Piton de la afficher le fichier. Protocole de l'activitĂ© 2 partie 2 : comment dĂ©tecter des ondes sismiques provenant d’un Ă©picentre Ă©loignĂ© ? Support us - Help us upgrade our services! We truly love working to bring you the latest volcano and earthquake data from around the world. Maintaining our website and our free apps does require, however, considerable time and resources. We need financing to increase hard- and software capacity as well as support our editor team. We're aiming to achieve uninterrupted service wherever an earthquake or volcano eruption unfolds, and your donations can make it happen! Every donation will be highly appreciated. If you find the information useful and would like to support our team in integrating further features, write great content, and in upgrading our soft- and hardware, please make a donation PayPal or Online credit card payment.Planned featuresImproved multilanguage supportTsunami alertsFaster responsivenessThanks to your past donations, these features have been added recentlyEarthquake archive from 1900 onwardsDetailed quake statsAdditional seismic data sources Download and Upgrade the Volcanoes & Earthquakes app to get one of the fastest seismic and volcano alerts onlineAndroid IOSThank you! . 30 355 415 295 498 79 222 388

camera volcan piton de la fournaise