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Sketch map of Mount Etna showing location of the volcano and study area (dark grey rectangle). The active summit craters are also indicated (VOR = Voragine; NEC = Northeast Crater; BN = Bocca Nuova; SEC = Southeast Crater).
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Morphostructural data derived from Lidar (Light detection and ranging) surveys carried out on Mount Etna in 2005 and 2007 are compared with earlier aerophotogrammetric surveys in 1986 and 1998. These data render an unprecedentedly clear and quantitative image of morphostructural and volumetric changes that have affected the summit area of the volca...
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Context 1
... produce deposits that can lead to growth in height of their summits or to destruction and loss in height of portions of their edifices. Mount Etna in Sicily, Italy (Figure 1), is an instructive examples of this type, where the frequent eruptive activity of the last few decades has led to profound changes in the morphology. Since 1986, for example, Etna has produced ten major lava outflows and about 200 paroxysmal events (e.g. ...
Context 2
... During the interval 1986-2007, Etna erupted nearly every year from its summit and frequently from its flanks Allard et al., 2006]. Most of the activity occurred at the Southeast Crater (SEC in Figure 1), particularly in 1989 -1990, 1996 -2001, and 2006 -2007. This resulted in a net growth of the SEC cone until 2001, which was followed by partial collapse in 2004 -2006, renewed growth in 2006 -2007, and minor collapse in the spring of 2007. ...
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In the field of official topographic cartography Serbia has a long tradition which origin dates from Princedom of Serbia. On the territory of Serbia and former federal state, there have been conducted several surveys in the field, of which the last one was conducted in the period from 1947 to 1967. Based on that survey, the entire area of ex state...
Citations
... LiDAR systems operated from airplanes and helicopters have been widely applied to earth science and other investigations [3][4][5][6][7][8][9][10], facilitating the coverage of relatively large areas in a short amount of time, showing a high resistance to interference, and remaining unaffected by illumination conditions, such as shadows [2,11,12]. Therefore, LiDAR stands out as a unique remote-sensing technique capable of accurately detecting geomorphological features in entirely or partly vegetated areas. ...
Over the past two decades, the airborne Light Detection and Ranging (LiDAR) system has become a useful tool for acquiring high-resolution topographic data, especially in active tectonics studies. Analyzing Digital Terrain Models (DTMs) from LiDAR exposes morpho-structural elements, aiding in the understanding of fault zones, among other applications. Despite its effectiveness, challenges persist in regions with rapid deformation, dense vegetation, and human impact. We propose an adapted workflow transitioning from the conventional airborne LiDAR system to the usage of drone-based LiDAR technology for higher-resolution data acquisition. Additionally, drones offer a more cost-effective solution, both in an initial investment and ongoing operational expenses. Our goal is to demonstrate how drone-based LiDAR enhances the identification of active deformation features, particularly for earthquake-induced surface faulting. To evaluate the potential of our technique, we conducted a drone-based LiDAR survey in the Casamicciola Terme area, north of Ischia Island, Italy, known for the occurrence of destructive shallow earthquakes, including the 2017 Md = 4 event. We assessed the quality of our acquired DTM by comparing it with existing elevation datasets for the same area. We discuss the advantages and limitations of each DTM product in relation to our results, particularly when applied to fault mapping. By analyzing derivative DTM products, we identified the fault scarps within the Casamicciola Holocene Graben (CHG) and mapped its structural geometry in detail. The analysis of both linear and areal geomorphic features allowed us to identify the primary factors influencing the current morphological arrangement of the CHG area. Our detailed map depicts a nested graben formed by two main structures (the Maio and Sentinella faults) and minor internal faults (the Purgatorio and Nizzola faults). High-resolution DEMs acquired by drone-based LiDAR facilitated detailed studies of the geomorphology and fault activity. A similar approach can be applied in regions where the evidence of high slip-rate faults is difficult to identify due to vegetation cover and inaccessibility.
... The Stromboli volcano extends above the sea for up to 924 m and below the sea down to~-2000 m depth [102][103][104][105]. Thus, considering the whole size of the volcanic edifice, it is often compared in size to Mt. Etna, which rises up to 3347 m a.s.l. [106][107][108]. However, the sizes and capacities of the plumbing systems of the two volcanoes are notably different [109][110][111][112][113][114], and this is also testified by the large difference between the erupted volumes. ...
Stromboli is an open-conduit active volcano located in the southern Tyrrhenian Sea and is the easternmost island of the Aeolian Archipelago. It is known as “the lighthouse of the Mediterranean” for its continuous and mild Strombolian-type explosive activity, occurring at the summit craters. Sometimes the volcano undergoes more intense explosions, called “major explosions” if they affect just the summit above 500 m a.s.l. or “paroxysms” if the whole island is threatened. Effusive eruptions are less frequent, normally occurring every 3–5 years, and may be accompanied or preceded by landslides, crater collapses and tsunamis. Given the small size of the island (maximum diameter of 5 km, NE–SW) and the consequent proximity of the inhabited areas to the active craters (maximum distance 2.5 km), it is of paramount importance to use all available information to forecast the volcano’s eruptive activity. The availability of a detailed record of the volcano’s eruptive activity spanning some centuries has prompted evaluations on its possible short-term evolution. The aim of this paper is to present some statistical insights on the eruptive activity at Stromboli using a catalogue dating back to 1879 and reviewed for the events during the last two decades. Our results confirm the recent trend of a significant increase in major explosions, small lava flows and summit crater collapses at the volcano, and might help monitoring research institutions and stakeholders to evaluate volcanic hazards from eruptive activity at this and possibly other open-vent active basaltic volcanoes.
... In literature, the mapping and volume quantifications of the Etna morphological changes are often referred to single eruptive events and estimated by the following methodologies: i) extrapolations from field data and modelling (Coltelli et al., 2007;Andronico et al., 2008); ii) estimations obtained by thermal remote sensing techniques (Harris et al. 1997;1998;Bailey et al., 2006;Lombardo et al., 2011); iii) comparison between Digital Elevation Models (DEMs) before and immediately after the eruptive event (Neri et al., 2008;De Beni et al., 2019;Proietti et al., 2020). The first method, requiring proper collection of field data, depends on the accessibility and the extent of the erupted deposits. ...
The topography of Mt. Etna, Italy, is subjected to continuous modifications depending on intensity and magnitude of eruptions that frequently occur at the volcano summit and flanks. In order to make high-resolution maps of morphological changes and accurately calculate the overall volume of the erupted products (e.g., lava flows, tephra fall out, scoriae cones) in ten years, we have compared the altimetry models of Mt. Etna derived from 2005 Airborne Laser Scanning data and 2015 Pleiades stereo satellite imagery. Both models cover a common area of 400 km² with spatial resolution of 2 m and comparable vertical accuracy (RMSE < 0.8 m). The results show that the area most affected by the erupted products is the mid-upper portion of the volcano with an altitude ranging from 1300 m to more than 3300 m a.s.l., value reached at the summit of the North East crater. In particular, this portion changes dramatically in the eastern sector due to the birth and growth of the New South-East Crater, the invasion of dozens of lava flows in the Valle del Bove, and the formation of the 2014 scoriae cones and lava field at the base of the North-East Crater. The total volume of products erupted in the investigated period results in 284.3±15.8 x 10⁶ m³ with a yearly average volume of 28.4 x 10⁶ m³/y comparable with the previous decades. In addition, the products emitted by the 2014 sub-terminal eruption are mapped and quantified including, for the first time, the volume of the 2014 scoriae cones generated on the eastern flank of North-East Crater This study demonstrates how a rigorous comparison between digital elevation models derived from different remote sensing techniques produce high accurate mapping and quantifications of morphological changes applicable for worldwide active volcanoes. This allows to quantify volumes and areas of erupted products reducing the error estimations, a crucial point to provide precise data often used as key parameters for many volcanic hazard studies.
... In the last two decades, specific remote sensing techniques such as Airborne Laser Scanning (ALS), aerial stereo photogrammetry combined with SfM (Structure from Motion) elaboration, and satellite stereo photogrammetry, result to be the most diffused to create Digital Elevation Model (DEM) in volcanic areas (Pesci et al., 2007;James and Robson, 2012;Jones et al., 2015;Bisson et al., 2016;Müller et al., 2017;Beyer et al., 2018;De Beni et al., 2019). Such models, properly analysed and compared, allowed i) to study the morphology of the same volcano in different times (Neri et al., 2008), ii) to produce a series of data useful to better document and understand the eruptive history of the volcano itself (Marsella et al., 2012;Dai and Howat, 2017;Whelley et al., 2017;Ganci et al., 2018) and iii) to simulate volcanic phenomena and their impact on the territory producing maps useful to mitigate the hazard and risk volcanic (Felpeto et al., 2001;Huggel et al., 2008;Cappello et al., 2011;Salvatici et al., 2016;Annis et al., 2020). The morphology of a volcano before the 1980's cannot be obviously reproduced with the previously mentioned remote sensing techniques and hereupon the available historical cartography, with all its limits (Balletti, 2000), becomes the only reference data. ...
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... From 1971 to 2007, the subterminal Southeast Crater (SEC) developed between 3000 and 3200 meters . Since 2011, on the south-eastern flank of the SEC, a further imposing pyroclastic cone named New Southeast Crater has started to grow; its feed axis shifted about 300 m to the SE with respect to the SEC (Behncke et al., 2014;Corsaro et al., 2017;De Beni et al., 2015;Neri et al., 2008Neri et al., , 2017Vicari et al., 2011). ...
... The Central Crater and the Northeast Crater, have undergone striking morpho-structural transformations, alternating hundreds of meters subsidence, intra-crateric strombolian activity, lava fountaining and the growth of pyroclastic cones, sometimes active continuously for many months (Allard et al., 2006;Corsaro et al., 2017;Marchese et al., 2018;Neri et al., 2008Neri et al., , 2017. ...
UAVs have become a useful tool for natural hazard monitoring. In volcanic areas, they allow wider observations of the eruptive behaviour, with no risk for the operator. The SfM technique enables obtaining orthoimages of lava flows and a DEM in a short time. These data are also useful to estimate lava flow volumes and the mass output rate characterizing an eruption. We present the results of ten UAV surveys made during and after the 30 May – 6 June 2019 eruption of Etna volcano, projecting the data in a time context back until 1999. Orthoimages taken on different days allowed monitoring the morpho-structural evolution of the fissures, capturing the lava flows propagation and the accumulation of pyroclastic deposits. From 1999 to 2018, there were nine flank-eruptions and dozens of summit-eruptions, which for graphic simplicity have been grouped by year in the map. The resulting map represents the most updated of the recent lava flows of Etna.
... Topographic monitoring of lava flow fields by means of LIDAR (Neri et al., 2008;Fornaciai et al., 2010), laser scanner (Slatcher et al., 2015), Unmanned Aerial Vehicles (Turner et al., 2017;Favalli et al., 2018) and helicopter (Neri et al., 2017), has been proven to be very effective and precise in detecting and quantifying erupted products and morphological variations (Muller et al., 2017;Darmawan et al., 2018), even if these approaches are often impractical, especially in remote volcanoes, or when a large area is affected by changes due to eruptive events. An alternative is offered by optical satellites in multi-view configuration (e.g. ...
Satellite remote sensing is becoming an increasingly essential component of volcano monitoring, especially at little-known and remote volcanoes where in-situ measurements are unavailable and/or impractical. Moreover the synoptic view captured by satellite imagery over volcanoes can benefit hazard monitoring efforts. By monitoring, we mean both following the changing styles and intensities of the eruption once it has started, as well as nowcasting and eventually forecasting the areas potentially threatened by hazardous phenomena in an eruptive scenario. Here we demonstrate how the diversity of remote sensing data over volcanoes and the mutual interconnection between satellite observations and numerical simulations can improve lava flow hazard monitoring in response to effusive eruption. Time-averaged discharge rates (TADRs) obtained from low spatial/high temporal resolution satellite data (e.g. MODIS, SEVIRI) are complemented, compared and fine-tuned with detailed maps of volcanic deposits with the aim of constraining the conversion from satellite-derived radiant heat flux to TADR. Maps of volcanic deposits include the time-varying evolution of lava flow emplacement derived from multispectral satellite data (e.g. EO-ALI, Landsat, Sentinel-2, ASTER), as well as the flow thickness variations, retrieved from the topographic monitoring by using stereo or tri-stereo optical data (e.g. Pléiades, PlanetScope, ASTER). Finally, satellite-derived parameters are used as input and validation tags for the numerical modelling of lava flow scenarios. Our strategy is applied to the first historic eruption of Nabro volcano (Eritrea), occurred in June 2011. This eruptive event was characterized by the extraordinary quantity of SO2 emitted into the atmosphere and the extent of the long lava flows, which had a significant impact on the inhabitants of the Eritrea-Ethiopia border region despite the low population density. Because of its remote position, little was known about this eruption regarding the quantity of volcanic deposits and the timing and mechanisms of their emplacement. We found that the total volume of deposits, calculated from differences of digital elevation models (DEMs), is about 580 × 10⁶ m³, of which about 336 × 10⁶ m³ is the volume of the main lava flow that advanced eastward beyond the caldera. Multi-spectral satellite observations indicate that the main lava flow had reached its maximum extent (~16 km) within about 4 days of the eruption onset on midnight 12 June. Lava flow simulations driven by satellite-derived parameters allow building an understanding of the advance rate and maximum extent of the main lava flow showing that it is likely to have reached 10.5 km in one day with a maximum speed of ~0.44 km/h.
... Etna with high spatial resolution and good accuracy [17,18]. Several DEMs reproduce only limited portions of the volcano, generally those affected by a specific eruptive event [19][20][21]. Often, these limited portions of topography are combined with older and larger area models of Mt. Etna to obtain what may be considered updated DEMs of the whole volcano. ...
... Several topographies of Mt. Etna have been produced during the last 15 years using data acquired by digital cartography maps [22], aerial stereo photogrammetry [17,21], airborne laser scanning [19,20] and, most recently by satellite stereo photogrammetry [23]. In addition, during the 2018 and 2019 volcanic activity, the areas affected by lava flows were surveyed by unmanned aerial vehicle (UAV) and data were processed using structure from motion (SfM). ...
... Mt. Etna is the highest active continental volcano in Europe (3329.6 m above sea level as measured by an airborne laser scanning survey in the summer of 2007) [20], and it emerges along the northeastern coast of Sicily (Southern Italy), covering an area of about 1200 km 2 considering the basal boundary ( Figure 1). The area is densely populated with hundreds of thousands of local people and tourists living near the volcano and visiting it. ...
The areas characterized by dynamic and rapid morphological changes need accurate topography information with frequent updates, especially if these are populated and involve infrastructures. This is particularly true in active volcanic areas such as Mount (Mt.) Etna, located in the northeastern portion of Sicily, Italy. The Mt. Etna volcano is periodically characterized by explosive and effusive eruptions and represents a potential hazard for several thousands of local people and hundreds of tourists present on the volcano itself. In this work, a high-resolution, high vertical accuracy digital surface model (DSM) of Mt. Etna was derived from Pleiades satellite data using the National Aeronautics and Space Administration (NASA) Ames Stereo Pipeline (ASP) tool set. We believe that this is the first time that the ASP using Pleiades imagery has been applied to Mt. Etna with sub-meter vertical root mean square error (RMSE) results. The model covers an area of about 400 km 2 with a spatial resolution of 2 m and centers on the summit portion of the volcano. The model was validated by using a set of reference ground control points (GCP) obtaining a vertical RMSE of 0.78 m. The described procedure provides an avenue to obtain DSMs at high spatial resolution and elevation accuracy in a relatively short amount of processing time, making the procedure itself suitable to reproduce topographies often indispensable during the emergency management case of volcanic eruptions.
... Two ALS DEMs collected in 2005 and 2007 were used, together with aerial photogrammetry from 1986 and 1998, in order to estimate changes to the summit height and size of Mt. Etna (Neri et al., 2008). A substantial increase in elevation both on and around the volcano was found though the ALS data was noted to be, by far, the more accurate data collection technique, permitting more precise measurements of change between 2005 and 2007. ...
In the last two decades, airborne laser scanning (ALS) has found widespread application and driven fundamental advances in the Earth sciences. With increasing availability and accessibility, multi-temporal ALS data have been used to advance key research topics related to dynamic Earth surface processes. This review presents a comprehensive compilation of existing applications of ALS change detection to the Earth sciences. We cover a wide scope of material pertinent to the broad field of Earth sciences to encourage the cross-pollination between sub-disciplines and discuss the outlook of ALS change detection for advancing scientific discovery. While significant progress has been made in applying repeat ALS data to change detection, numerous approaches make fundamental assumptions that limit the full potential of repeat ALS data. The use of such data for 3D change detection is, therefore, in need of novel, scalable, and computationally efficient processing algorithms that transcend the ever-increasing data density and spatial coverage. Quantification of uncertainty in change detection results also requires further attention, as it is vitally important to understand what 3D differences detected between epochs represent actual change as opposed to limitations in data or methodology. Although ALS has become increasingly integral to change detection across the Earth sciences, the existence of pre- and post-event ALS data is still uncommon for many isolated hazard events, such as earthquakes, volcanic eruptions, wildfires, and landslides. Consequently, data availability is still a major limitation for many ALS change detection applications.
... The first eruptive activity at Etna dates back to about 600 ka ago and set up the basaltic stratovolcano in a complex geodynamic environment between the Gela-Catania foredeep and the Hyblean Foreland, which is the front of the orogenic belt overlapping the African continental plate margin12. North East Crater (NEC), Bocca Nuova (BN), Voragine (VOR), South East Crater (SEC), and New South East Crater (NSEC) are the present main eruptive centers located at the top of the volcano, which is 3329 m high13(Fig. 1). ...
Early-warning assessment of a volcanic unrest requires that accurate information from monitoring is continuously gathered before volcanic activity starts. Seismic data are an optimal source of such information, overcoming safety problems due to dangerous conditions for field surveys or cloud cover that may hinder visibility. We designed a multi-station warning system based on the classification of patterns of the background seismic radiation, so-called volcanic tremor, by using Self-Organizing Maps (SOM) and fuzzy clustering. The classifier automatically detects patterns that are typical footprints of volcanic unrest. The issuance of the SOM colors on DEM allows their geographical visualization according to the stations of detection; this spatial location makes it possible to infer areas potentially impacted by eruptive phenomena. Tested at Mt. Etna (Italy), the classifier forecasted in hindsight patterns associated with fast-rising magma (typical of lava fountains) as well as a relatively long lead time of the outburst (lava flows from eruptive fractures). Receiver Operating Characteristics (ROC) curves gave an Area Under the Curve (AUC) ∼0.8 indicative of a good detection accuracy that cannot be achieved from a mere random choice.
... Finally, the NSEC has formed in 2007 as a pit crater at the South-east base of the SEC (Acocella et al., 2016), but rapidly grew during the lava fountains occurred since January 2011 . After the last flank eruption in 2008-2009(Ganci et al., 2012b, the volcanic activity of Etna has shown a more explosive behavior, with an increasing number of paroxysmal events at the summit craters (Bonaccorso and Calvari, 2013;Cappello et al., 2013). Indeed, from 2011 to 2015, the SEC area has been the source of 53 eruptive episodes, most of them characterized by the emission of lava fountains, pyroclastic material, and short-lasting lava flows that mostly spread within the Valle del Bove (VdB). ...
... It is a DEM at 1 m spatial resolution resulted from a digital photogrammetric mapping, applying the airborne HRSC-AX sensor and photogrammetric processing system (Gwinner et al., 2006). After this, only local updates of the summit area have been derived from Light Detection And Ranging (LIDAR), digital photogrammetry and/or terrestrial laser scanning in 2007, 2010, 2012(Neri et al., 2008Caracciolo D'Ajello et al., 2014;De Beni et al., 2015;Behncke et al., 2016). As post-eruptive base, we considered a topography produced using satellite images from the Pléiades constellation acquired on 18 December 2015. ...
... By differencing the 2005 and 2015 DEMs and excluding the volume of the NSEC cone, we obtained a 10-year volume of ∼232 × 10 6 m 3 , which is below the recent erupted volumes on decadal scale at Mt Etna (∼300 × 10 6 m 3 from Harris et al., 2011), interrupting its stable and resilient output trend. By further subtracting published products retrieved from LIDAR analysis in 2007 and 2010 (Neri et al., 2008;Behncke et al., 2016), we found ∼131 million of cubic meters of eruptive products emitted since 2011, which is still about ∼25 × 10 6 m 3 higher than the volumes derived by SEVIRI. This difference, ranging between 10 and 30% of the total volume, is most likely due to loose materials as the pyroclastic fallout deposits in the same area where the lavas were emplaced and/or to the presence of tephra-covered snow. ...
Estimates of lava volumes provide important data on the lava flooding history and evolution of a volcano. For mapping volcanic deposits, including lava flows, the advancement of satellite remote sensing techniques offers a great potential. Here we characterize the eruptive events occurred at Mt Etna between January 2011 and December 2015 leading to the emplacement of numerous lava flows and to the formation of a new pyroclastic cone (NSEC) on the eastern flank of the South East Crater. The HOTSAT system is used to analyze remote sensing data acquired by the SEVIRI sensor in order to detect the thermal anomalies from active lava flows and calculate the associated radiative power. The time-series analysis of SEVIRI data provides an estimation of event magnitude and intensity of the effusive material erupted during each event. The cumulative volume estimated from SEVIRI images from 2011 to 2015 adds up to ~106 millions of cubic meters of lava, with a time-averaged rate of ~0.68 m³ s⁻¹. This estimate is independently supported and bounded using a topographic approach, i.e., by subtracting the last topography of Etna updated to 2005 from a 2015 digital elevation model (DEM), produced using tri-stereo Pléiades satellite images acquired on December 18, 2015. The total volume of products erupted from 2005 to 2015, calculated from topography difference by integration of the thickness distribution over the area covered, is about 287 × 10⁶ m³, of which ~55 × 10⁶ m³ is the volume of the NSEC cone. This 10-year volume is below the typical erupted volumes on decadal scale at Mt Etna, interrupting its stable and resilient output trend.
