Movements of the Sciara Del Fuoco

Author(s):  
A. Bonforte ◽  
M. Aloisi ◽  
G. Antonello ◽  
N. Casagli ◽  
J. Fortuny-Guash ◽  
...  
Keyword(s):  
2021 ◽  
Author(s):  
Federico Di Traglia ◽  
Claudio De Luca ◽  
Alessandro Fornaciai ◽  
Mariarosaria Manzo ◽  
Teresa Nolesini ◽  
...  

<p>Steep-slope volcanoes are geomorphological systems receptive to both exogenous and endogenous phenomena. Volcanic activity produces debris and lava accumulation, whereas magmatic/tectonic and gravitational processes can have a destructive effect, triggering mass-wasting and erosion.</p><p>Optical and radar sensors have often been used to identify areas impacted by eruptive and post-eruptive phenomena, quantify of topographic changes, and/or map ground deformation related to magmatic-tectonic-gravitational processes.</p><p>In this work, the slope processes on high-gradient volcano flanks in response to shift in volcanic activity have been identified by means of remote sensing techniques. The Sciara del Fuoco unstable flank of Stromboli volcano (Italy) was studied, having a very large set (2010-2020) of different remote sensing data available.</p><p>Data includes LiDAR and tri-stereo PLEIADES-1 DEMs, high-spatial-resolution (HSR) optical imagery (QUICKBIRD and PLEIADES-1), and space-borne and ground-based Synthetic Aperture Radar (SAR) data. Multi-temporal DEMs and HSR optical imagery permits to map areas affected by major lithological and morphological changes, and the volumes of deposited/eroded material. The results lead to the identification of topographical variations and geomorphological processes that occurred in response to the variation in eruptive intensity. The joint exploitation of space-borne and ground-based Differential and Multi Temporal SAR Interferometry (InSAR and MT-InSAR) measurements revealed deformation phenomena affecting the volcano edifice, and in particular the Sciara del Fuoco flank.</p><p>The presented results demonstrate the effectiveness of the joint exploitation of multi-temporal DEMs, HSR optical imagery, and InSAR measurements obtained through satellite and terrestrial SAR systems, highlighting their strong complementarity to map and interpret the slope phenomena in volcanic areas.</p><p>This work was financially supported by the “Presidenza del Consiglio dei Ministri – Dipartimento della Protezione Civile” (Presidency of the Council of Ministers – Department of Civil Protection); this publication, however, does not reflect the position and official policies of the Department".</p>


2021 ◽  
Author(s):  
Irene Manzella ◽  
Symeon Makris ◽  
Federico Di Traglia ◽  
Karim Kelfoun ◽  
Paul Cole ◽  
...  

<p>As demonstrated by the Anak Krakatau eruption-induced flank collapse in 2018 in Indonesia, tsunamis generated by large mass flows like landslides and pyroclastic density currents can have devastating effects in volcanic areas. However, these phenomena are still poorly understood as they are unusual and complex events, largely unpredictable and often poorly constrained. </p><p>Stromboli is one of the most active volcanoes in the world, extensively monitored and studied in the last few decades. Many tsunamigenic landslides (sub-aerial and/or submarine) have taken place; at least seven have occurred in the last 150 years and a devastating one is believed to have reached the coast of Naples, at more than 200 km distance, during the Middle Ages. Because the level of activity of the volcano has remained similar ever since and the likelihood of such disastrous events is not negligible, the hazard related to tsunamigenic mass flows in this area needs to be carefully assessed.</p><p>Associated with the 3<sup>rd</sup> of July 2019 eruption, at least three mass flows were triggered along the Sciara del Fuoco slope; two subaerial Pyroclastic density currents (PDCs) and a submarine landslide. Simultaneously, three buoys registered the height of the resulting tsunami wave ranging from 0.2 m in front of the Ginostra village to 1.5 m in front of the Sciara del Fuoco. Thanks to the dense monitoring network and the accurate bathymetry survey carried out by the IGAG-CNR, these events have been well constrained. </p><p>The tsunami waves studied here are smaller than those that could constitute a threat for the population living in this area, nevertheless they can be used to characterize the behaviour of the tsunamigenic mass flows. Back analysis of these events were undertaken with the two-fluids version of VolcFlow; this is a continuum mechanics model based on the depth-average approximation that has been developed for the simulation of volcanic flows. VolcFlow can take into account several different rheologies for each of the two fluids. In the present case, one fluid was used for the water body and one for simulating the mass flow. For the latter one, a constant retaining stress type of rheology was used (Dade and Huppert, 1998). Backanalysis suggested that it was the PDC which generated the tsunami wave during the events of July 2019 and best fitting simulations identified a constant retaining stress of 7kPa. With these input parameters it has been possible to run a large number of numerical simulations of possible scenarios. This has allowed to assess threshold values of volume and discharge of mass flows which could generate significant and potentially destructive tsunami waves. This constitutes an important input to improve early warning systems and to reduce the risk related to these unpredictable but extremely dangerous phenomena.</p>


2006 ◽  
Vol 43 (1) ◽  
pp. 41-55 ◽  
Author(s):  
Roberto Carniel ◽  
Ramon Ortiz ◽  
Mauro Di Cecca

Stromboli volcano is well known for its continuous strombolian activity. Moreover, the volcano occasionally shows effusive phases, the latest in 1985–1986. On 28 December 2002 Stromboli entered a new effusive phase, accompanied by different paroxysmal events that led to considerable hazards for inhabitants and tourists on the island of Stromboli. On 30 December 2002 a major sector collapse affected the Sciara del Fuoco slope and initiated a tsunami. On 5 April 2003 a powerful explosion, which can be compared in size with the most recent explosion in 1930, covered a large part of the normally tourist accessible summit area with bombs. As this explosion was not forecasted, although the island was by then effectively monitored by a dense deployment of instruments, in this paper, we tackle the problem of highlighting the time scale of preparation of this event and conduct a search for possible precursors. For this purpose, we analyze the seismic data preceding the paroxysm with spectral and dynamical methods, highlighting that this paroxysmal event can be seen as the final result of a dynamical phase that started at least 2.5 h before the event. Therefore, this is the time scale during which the search can and should be made for possible precursors. Moreover, the application of the "material failure forecast" method suggests that this final dynamical phase may be just the final acceleration of a process that was building up for at least several days prior to the event.


2020 ◽  
Author(s):  
Massimo Orazi ◽  
Flora Giudicepietro ◽  
Carmen López ◽  
Giovanni Macedonio ◽  
Salvatore Alparone ◽  
...  

<p>In summer 2019, two paroxysmal explosions occurred in Stromboli. The first one occurred on July 3, when the Strombolian ordinary eruptive activity did not show a significant intensification. The explosion formed an eruptive column more than 3 km high. A pyroclastic flow ran down the “Sciara del Fuoco” slope causing a victim and some injuries. Moreover, the pyroclastic flow spread over the sea surface for about one kilometer. On August 28, a second paroxysmal explosion occurred, similar to the previous one. Also in this case the eruption formed an eruptive column of more than 3 km and a pyroclastic flow that expanded along the “Sciara del Fuoco” slope and traveled about 1 km on the sea surface. In the period between the two paroxysms, effusive activity occurred from the summit crater area. The eruptive phase of summer 2019, which began with the paroxysm of 3 July, was not preceded by significant changes in the routinely monitored parameters, such as the hourly frequency (daily average) of the VLP events (typical of Stromboli) and the amplitude of the seismic signal (RSAM). For this reason, we have analyzed the seismic and dilatometric data, which were recorded by the INGV geophysical network in the period November 2018 - September 2019, focusing our attention on other parameters that can give indications on the activity state of the volcano. In particular, we analyzed the data of the broadband seismic stations, equipped with the Guralp CMG40T sensors, and the data of one Sacks-Evertson borehole strainmeter. We defined the "VLP size", which takes into account the waveform of the VLP events, in terms of both amplitude and duration. We also applied time varying Fractal Dimension (FD) analysis to the seismograms of a seismic station close to the crater area and we analyzed the polarization of the same signal. We carried out the polarization analysis both without applying a filter and by filtering the seismic signal in the typical frequency bands of the Stromboli volcanic tremor (1-3 Hz) and of the VLPs (0.5-0.05 Hz). We found that the "VLP size", the FD and the polarization parameters showed significant changes about one month before the paroxysm of July 3. In the short term, we applied an appropriately tuned STA/LTA algorithm to the data of the borehole strainmeter, which is installed on the island at about 2km from the craters, and we obtained an automatic detection of the paroxysmal events 10 and 7.5 minutes before the explosion of July 3 and August 28, respectively.</p>


2020 ◽  
Author(s):  
Filippo Zaniboni ◽  
Gianluca Pagnoni ◽  
Glauco Gallotti ◽  
Stefano Tinti ◽  
Alberto Armigliato

<p>The recent paroxysmal crisis occurring on the island of Stromboli (Tyrrhenian Sea, Italy), manifesting into two main events during summer 2019 (3<sup>rd</sup> July and 28<sup>th</sup> August), renovated the attention on the possibility of tsunami generation induced by volcanic activity. The Stromboli edifice is characterized by the Sciara del Fuoco scar on its north-western flank channeling most of the material ejected from the crater to the sea.</p><p>In this area, in December 2002, two landslides (the first submarine, the second subaerial) triggered large waves affecting the whole coast of the island, causing severe damages but fortunately no casualties, due to the non-touristic period. The tsunami rapidly dissipated with distance, being observed in Panarea (20 km south-east of Stromboli), as is typical of non-seismic tsunamigenic sources. A similar occurrence during summer would have resulted into dramatic consequences, especially along the Stromboli coasts.</p><p>In this study, the tsunamigenic potential associated with destabilized mass along Stromboli flanks is evaluated by means of numerical, in-house developed, codes with the aim of providing insights on the tsunami hazard along the coasts of Stromboli, of the surrounding Aeolian archipelago and in general in a larger domain covering the southern coasts of Tyrrhenian Sea as well.</p>


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