The San Bartolo eruption is the last flank eruption occurred at Stromboli volcano about 2 ka ago ... more The San Bartolo eruption is the last flank eruption occurred at Stromboli volcano about 2 ka ago on the NE flank of the island. Despite its importance in being the most recent example of flank activity outside the barren Sciara del Fuoco slope, where the recent activity concentrated, some important volcanological data, such as the duration and lava volume have not yet been provided. Here, we present a new simulation of the San Bartolo eruption carried out using a combination of field analyses and numerical modelling. In particular, we used the CL-HOTSAT satellite monitoring system to estimate the effusion rate and erupted volume of the 2002-03 eruption, which formed a similar lava flow field extending from about 600 m in elevation to the coast. These were used as input of the physics-based model GPUFLOW to reproduce the emplacement dynamics of the San Bartolo lava flow. The aim is to reconstruct the sequence of events and infer a possible duration and impact of the eruption. Our res...
2021 IEEE International Geoscience and Remote Sensing Symposium IGARSS, 2021
Satellite remote sensing is playing an increasing role in volcano monitoring, not only at little-... more Satellite remote sensing is playing an increasing role in volcano monitoring, not only at little-known and remote volcanoes where in-situ data are often unavailable, but also at well-monitored volcanoes to complement ground-based measurements. The synoptic view captured by multi-source satellite imagery over volcanoes can benefit hazard monitoring efforts, both following the different phases and intensities of an eruption, as well as helping in nowcasting and eventually forecasting the areas potentially threatened by hazardous phenomena. Here we demonstrate how satellite data from different sources can be combined to refine the satellite-derived radiant heat flux and time-averaged discharge rates (TADRs) estimation, and to improve real-time monitoring and nowcasting of eruptive events. This is achieved by cross-referencing TADRs obtained from low spatial/high temporal resolution satellite data (e.g. MODIS, SEVIRI, VIIRS, SLSTR) with maps of volcanic deposits including the time-varying evolution of lava flow emplacement derived from medium spatial resolution multispectral satellite data (e.g. EO-ALI, Landsat, Sentinel-2, ASTER), and with detailed three-dimensional maps of volcanic deposits retrieved from the topographic monitoring by using stereo or tri-stereo optical data (e.g. Pleiades, PlanetScope, SkySat, ASTER). Finally, satellite-derived parameters are used as input and validation for the numerical modelling of lava flow scenarios. This strategy is here applied to recent eruptions occurred on Etna, Stromboli and Nabro volcanoes.
During the last two decades, the Etna volcano has undergone several sequences of lava fountaining... more During the last two decades, the Etna volcano has undergone several sequences of lava fountaining (LF) events that have had a major impact on road conditions, infrastructure and the local population. In this paper, we consider the LF episodes occurring between 2011 and 2022, calculating their erupted volumes using the images recorded by the monitoring thermal cameras and applying a manual procedure and a dedicated software to determine the lava fountain height over time, which is necessary to obtain the erupted volume. The comparison between the results indicates the two procedures match quite well, the main differences occurring when the visibility is poor and data are interpolated. With the aim of providing insights for hazard assessment, we have fitted some probabilistic models of both the LF inter-event times and the erupted volumes of pyroclastic material. In more detail, we have tested power-law distributions against log-normal, Weibull, generalised Pareto and log-logistic. Re...
The Etna volcano is renowned worldwide for its extraordinary lava fountains that rise several kil... more The Etna volcano is renowned worldwide for its extraordinary lava fountains that rise several kilometers above the vent and feed eruptive columns, then drift hundreds of kilometers away from the source. The Italian Istituto Nazionale di Geofisica e Vulcanologia-Osservatorio Etneo (INGV-OE) is responsible for the monitoring of Mt. Etna, and for this reason, has deployed a network of visible and thermal cameras around the volcano. From these cameras, INGV-OE keeps a keen eye, and is able to observe the eruptive activity, promptly advising the civil protection and aviation authorities of any changes, as well as quantifying the spread of lava flows and the extent of pyroclastic and ash plumes by using a careful analysis of the videos recorded by the monitoring cameras. However, most of the work involves analysis carried out by hand, which is necessarily approximate and time-consuming, thus limiting the usefulness of these results for a prompt hazard assessment. In addition, the start of...
Between 13 December 2020 and 21 February 2022, Etna volcano produced a sequence of 66 paroxysmal ... more Between 13 December 2020 and 21 February 2022, Etna volcano produced a sequence of 66 paroxysmal explosive eruptions, with Strombolian activity at the summit craters climaxing in lava fountains and eruption columns extending several kilometers above the craters, accompanied by minor and short-lasting lava flows from the crater rim. We selected three of these episodes that occurred within a short space of time, between 13 December 2020 and 12 March 2021, of different magnitude (i.e., erupted volume) and intensity (i.e., mass eruption rate or instantaneous eruption rate), and analyzed them from a multidisciplinary perspective. The aim was to gain insights into those parameters that mostly reveal the eruptive process for hazard assessment purposes. The multidisciplinary data consist of calibrated visible images, thermal images, seismic and infrasound data, ground deformation detected from the strainmeters, as well as satellite SEVIRI images. From these data, we obtained the timing of e...
Open conduit volcanoes like Stromboli can display elusive changes in activity before major erupti... more Open conduit volcanoes like Stromboli can display elusive changes in activity before major eruptive events. Starting on December 2020, Stromboli volcano displayed an increasing eruptive activity, that on 19 May 2021 led to a crater-rim collapse, with pyroclastic density currents (PDCs) that spread along the barren NW flank, entered the sea and ran across it for more than 1 km. This episode was followed by lava flow output from the crater rim lasting a few hours, followed by another phase of lava flow in June 2021. These episodes are potentially very dangerous on island volcanoes since a landslide of hot material that turns into a pyroclastic density current and spreads on the sea surface can threaten mariners and coastal communities, as happened at Stromboli on 3 July and 28 August 2019. In addition, on entering the sea, if their volume is large enough, landslides may trigger tsunamis, as occurred at Stromboli on 30 December 2002. In this paper, we present an integration of multidis...
The monitoring of active volcanoes is a complex task based on multidisciplinary and integrated an... more The monitoring of active volcanoes is a complex task based on multidisciplinary and integrated analyses that use ground, drones, and satellite monitoring devices [...]
Crater-wall collapses are fairly frequent at active volcanoes and they are normally studied throu... more Crater-wall collapses are fairly frequent at active volcanoes and they are normally studied through the analysis of their deposits. In this paper, we present an analysis of the 12 January 2013 crater-wall collapse occurring at Stromboli volcano, investigated by means of a monitoring network comprising visible and infrared webcams and a Ground-Based Interferometric Synthetic Aperture Radar. The network revealed the triggering mechanisms of the collapse, which are comparable to the events that heralded the previous effusive eruptions in 1985, 2002, 2007 and 2014. The collapse occurred during a period of inflation of the summit cone and was preceded by increasing explosive activity and the enlargement of the crater. Weakness of the crater wall, increasing magmastatic pressure within the upper conduit induced by ascending magma and mechanical erosion caused by vent opening at the base of the crater wall and by lava fingering, are considered responsible for triggering the collapse on 12 January 2013 at Stromboli. We suggest that the combination of these factors might be a general mechanism to generate crater-wall collapse at active volcanoes.
Two paroxysmal explosions occurred at Stromboli on July 3 and August 28, 2019, the first of which... more Two paroxysmal explosions occurred at Stromboli on July 3 and August 28, 2019, the first of which caused the death of a young tourist. After the first paroxysm an effusive activity began from the summit vents and affected the NW flank of the island for the entire period between the two paroxysms. We carried out an unsupervised analysis of seismic and infrasonic data of Strombolian explosions over 10 months (15 November 2018–15 September 2019) using a Self-Organizing Map (SOM) neural network to recognize changes in the eruptive patterns of Stromboli that preceded the paroxysms. We used a dataset of 14,289 events. The SOM analysis identified three main clusters that showed different occurrences with time indicating a clear change in Stromboli’s eruptive style before the paroxysm of 3 July 2019. We compared the main clusters with the recordings of the fixed monitoring cameras and with the Ground-Based Interferometric Synthetic Aperture Radar measurements, and found that the clusters ar...
Journal of Geophysical Research: Solid Earth, 2015
This paper was partially supported by a grant to S.C. (Project INGV-DPC Paroxysm V2/03, 2008–2010... more This paper was partially supported by a grant to S.C. (Project INGV-DPC Paroxysm V2/03, 2008–2010) funded by the Istituto Nazionale di Geofisica e Vulcanologia and by the Italian Civil Protection.
Geological Society, London, Special Publications, 2015
Etna volcano is characterized by frequent effusive eruptions from the summit craters or from flan... more Etna volcano is characterized by frequent effusive eruptions from the summit craters or from flank fissures, and these have often threatened villages, infrastructures and tourist facilities. Considerable experience of lava-flow mitigation has been gained by scientists working on this volcano, and in this paper we principally discuss the problems arising from lava flows emplaced during the 2002–03 flank eruption, when eruptive fissures opened both on the northern and southern flanks of the volcano, feeding lava flows towards several villages, tourist facilities and forests. We highlight the importance of the monitoring system to follow the spreading of eruptive fissures and predict when they stopped propagating. We illustrate the value of thermal mapping in identifying active lava flows, in measuring effusion rates to estimate the maximum distance that flows can travel, and in obtaining reliable lava-flow simulations in real time in order to predict possible paths of the lava flow an...
The San Bartolo eruption is the last flank eruption occurred at Stromboli volcano about 2 ka ago ... more The San Bartolo eruption is the last flank eruption occurred at Stromboli volcano about 2 ka ago on the NE flank of the island. Despite its importance in being the most recent example of flank activity outside the barren Sciara del Fuoco slope, where the recent activity concentrated, some important volcanological data, such as the duration and lava volume have not yet been provided. Here, we present a new simulation of the San Bartolo eruption carried out using a combination of field analyses and numerical modelling. In particular, we used the CL-HOTSAT satellite monitoring system to estimate the effusion rate and erupted volume of the 2002-03 eruption, which formed a similar lava flow field extending from about 600 m in elevation to the coast. These were used as input of the physics-based model GPUFLOW to reproduce the emplacement dynamics of the San Bartolo lava flow. The aim is to reconstruct the sequence of events and infer a possible duration and impact of the eruption. Our res...
2021 IEEE International Geoscience and Remote Sensing Symposium IGARSS, 2021
Satellite remote sensing is playing an increasing role in volcano monitoring, not only at little-... more Satellite remote sensing is playing an increasing role in volcano monitoring, not only at little-known and remote volcanoes where in-situ data are often unavailable, but also at well-monitored volcanoes to complement ground-based measurements. The synoptic view captured by multi-source satellite imagery over volcanoes can benefit hazard monitoring efforts, both following the different phases and intensities of an eruption, as well as helping in nowcasting and eventually forecasting the areas potentially threatened by hazardous phenomena. Here we demonstrate how satellite data from different sources can be combined to refine the satellite-derived radiant heat flux and time-averaged discharge rates (TADRs) estimation, and to improve real-time monitoring and nowcasting of eruptive events. This is achieved by cross-referencing TADRs obtained from low spatial/high temporal resolution satellite data (e.g. MODIS, SEVIRI, VIIRS, SLSTR) with maps of volcanic deposits including the time-varying evolution of lava flow emplacement derived from medium spatial resolution multispectral satellite data (e.g. EO-ALI, Landsat, Sentinel-2, ASTER), and with detailed three-dimensional maps of volcanic deposits retrieved from the topographic monitoring by using stereo or tri-stereo optical data (e.g. Pleiades, PlanetScope, SkySat, ASTER). Finally, satellite-derived parameters are used as input and validation for the numerical modelling of lava flow scenarios. This strategy is here applied to recent eruptions occurred on Etna, Stromboli and Nabro volcanoes.
During the last two decades, the Etna volcano has undergone several sequences of lava fountaining... more During the last two decades, the Etna volcano has undergone several sequences of lava fountaining (LF) events that have had a major impact on road conditions, infrastructure and the local population. In this paper, we consider the LF episodes occurring between 2011 and 2022, calculating their erupted volumes using the images recorded by the monitoring thermal cameras and applying a manual procedure and a dedicated software to determine the lava fountain height over time, which is necessary to obtain the erupted volume. The comparison between the results indicates the two procedures match quite well, the main differences occurring when the visibility is poor and data are interpolated. With the aim of providing insights for hazard assessment, we have fitted some probabilistic models of both the LF inter-event times and the erupted volumes of pyroclastic material. In more detail, we have tested power-law distributions against log-normal, Weibull, generalised Pareto and log-logistic. Re...
The Etna volcano is renowned worldwide for its extraordinary lava fountains that rise several kil... more The Etna volcano is renowned worldwide for its extraordinary lava fountains that rise several kilometers above the vent and feed eruptive columns, then drift hundreds of kilometers away from the source. The Italian Istituto Nazionale di Geofisica e Vulcanologia-Osservatorio Etneo (INGV-OE) is responsible for the monitoring of Mt. Etna, and for this reason, has deployed a network of visible and thermal cameras around the volcano. From these cameras, INGV-OE keeps a keen eye, and is able to observe the eruptive activity, promptly advising the civil protection and aviation authorities of any changes, as well as quantifying the spread of lava flows and the extent of pyroclastic and ash plumes by using a careful analysis of the videos recorded by the monitoring cameras. However, most of the work involves analysis carried out by hand, which is necessarily approximate and time-consuming, thus limiting the usefulness of these results for a prompt hazard assessment. In addition, the start of...
Between 13 December 2020 and 21 February 2022, Etna volcano produced a sequence of 66 paroxysmal ... more Between 13 December 2020 and 21 February 2022, Etna volcano produced a sequence of 66 paroxysmal explosive eruptions, with Strombolian activity at the summit craters climaxing in lava fountains and eruption columns extending several kilometers above the craters, accompanied by minor and short-lasting lava flows from the crater rim. We selected three of these episodes that occurred within a short space of time, between 13 December 2020 and 12 March 2021, of different magnitude (i.e., erupted volume) and intensity (i.e., mass eruption rate or instantaneous eruption rate), and analyzed them from a multidisciplinary perspective. The aim was to gain insights into those parameters that mostly reveal the eruptive process for hazard assessment purposes. The multidisciplinary data consist of calibrated visible images, thermal images, seismic and infrasound data, ground deformation detected from the strainmeters, as well as satellite SEVIRI images. From these data, we obtained the timing of e...
Open conduit volcanoes like Stromboli can display elusive changes in activity before major erupti... more Open conduit volcanoes like Stromboli can display elusive changes in activity before major eruptive events. Starting on December 2020, Stromboli volcano displayed an increasing eruptive activity, that on 19 May 2021 led to a crater-rim collapse, with pyroclastic density currents (PDCs) that spread along the barren NW flank, entered the sea and ran across it for more than 1 km. This episode was followed by lava flow output from the crater rim lasting a few hours, followed by another phase of lava flow in June 2021. These episodes are potentially very dangerous on island volcanoes since a landslide of hot material that turns into a pyroclastic density current and spreads on the sea surface can threaten mariners and coastal communities, as happened at Stromboli on 3 July and 28 August 2019. In addition, on entering the sea, if their volume is large enough, landslides may trigger tsunamis, as occurred at Stromboli on 30 December 2002. In this paper, we present an integration of multidis...
The monitoring of active volcanoes is a complex task based on multidisciplinary and integrated an... more The monitoring of active volcanoes is a complex task based on multidisciplinary and integrated analyses that use ground, drones, and satellite monitoring devices [...]
Crater-wall collapses are fairly frequent at active volcanoes and they are normally studied throu... more Crater-wall collapses are fairly frequent at active volcanoes and they are normally studied through the analysis of their deposits. In this paper, we present an analysis of the 12 January 2013 crater-wall collapse occurring at Stromboli volcano, investigated by means of a monitoring network comprising visible and infrared webcams and a Ground-Based Interferometric Synthetic Aperture Radar. The network revealed the triggering mechanisms of the collapse, which are comparable to the events that heralded the previous effusive eruptions in 1985, 2002, 2007 and 2014. The collapse occurred during a period of inflation of the summit cone and was preceded by increasing explosive activity and the enlargement of the crater. Weakness of the crater wall, increasing magmastatic pressure within the upper conduit induced by ascending magma and mechanical erosion caused by vent opening at the base of the crater wall and by lava fingering, are considered responsible for triggering the collapse on 12 January 2013 at Stromboli. We suggest that the combination of these factors might be a general mechanism to generate crater-wall collapse at active volcanoes.
Two paroxysmal explosions occurred at Stromboli on July 3 and August 28, 2019, the first of which... more Two paroxysmal explosions occurred at Stromboli on July 3 and August 28, 2019, the first of which caused the death of a young tourist. After the first paroxysm an effusive activity began from the summit vents and affected the NW flank of the island for the entire period between the two paroxysms. We carried out an unsupervised analysis of seismic and infrasonic data of Strombolian explosions over 10 months (15 November 2018–15 September 2019) using a Self-Organizing Map (SOM) neural network to recognize changes in the eruptive patterns of Stromboli that preceded the paroxysms. We used a dataset of 14,289 events. The SOM analysis identified three main clusters that showed different occurrences with time indicating a clear change in Stromboli’s eruptive style before the paroxysm of 3 July 2019. We compared the main clusters with the recordings of the fixed monitoring cameras and with the Ground-Based Interferometric Synthetic Aperture Radar measurements, and found that the clusters ar...
Journal of Geophysical Research: Solid Earth, 2015
This paper was partially supported by a grant to S.C. (Project INGV-DPC Paroxysm V2/03, 2008–2010... more This paper was partially supported by a grant to S.C. (Project INGV-DPC Paroxysm V2/03, 2008–2010) funded by the Istituto Nazionale di Geofisica e Vulcanologia and by the Italian Civil Protection.
Geological Society, London, Special Publications, 2015
Etna volcano is characterized by frequent effusive eruptions from the summit craters or from flan... more Etna volcano is characterized by frequent effusive eruptions from the summit craters or from flank fissures, and these have often threatened villages, infrastructures and tourist facilities. Considerable experience of lava-flow mitigation has been gained by scientists working on this volcano, and in this paper we principally discuss the problems arising from lava flows emplaced during the 2002–03 flank eruption, when eruptive fissures opened both on the northern and southern flanks of the volcano, feeding lava flows towards several villages, tourist facilities and forests. We highlight the importance of the monitoring system to follow the spreading of eruptive fissures and predict when they stopped propagating. We illustrate the value of thermal mapping in identifying active lava flows, in measuring effusion rates to estimate the maximum distance that flows can travel, and in obtaining reliable lava-flow simulations in real time in order to predict possible paths of the lava flow an...
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Papers by Sonia Calvari