Overflows and Pyroclastic Density Currents in March-April 2020 at Stromboli Volcano Detected by Remote Sensing and Seismic Monitoring Data

Abstract

Between 28 March and 1 April 2020, Stromboli volcano erupted, with overflows from the NE crater rim spreading along the barren Sciara del Fuoco slope and reaching the sea along the NW coast of the island. Poor weather conditions did not allow a detailed observation of the crater zone through the cameras monitoring network, but a clear view of the lower slope and the flows expanding in the area allowed us to characterize the flow features. This evidence was integrated with satellite, GBInSAR, and seismic data, thus enabling a reconstruction of the whole volcanic event, which involved several small collapses of the summit cone and the generation of pyroclastic density currents (PDCs) spreading along the slope and on the sea surface. Satellite monitoring allowed for the mapping of the lava flow field and the quantification of the erupted volume, and GBInSAR continuous measurements detected the crater widening and the deflation of the summit cone caused by the last overflow. The characterization of the seismicity made it possible to identify the signals that are associated with the propagation of PDCs along the volcano flank and, for the first time, to recognize the signal that is produced by the impact of the PDCs on the coast.

Variable Magnitude and Intensity of Strombolian Explosions: Focus on the Eruptive Processes for a First Classification Scheme for Stromboli Volcano (Italy)

“…The explosion caused a blast spreading at first horizontally and, while the ash plume was still rising up, two pyroclastic density currents (PDCs) formed along the SdF, spreading down the slope and to the coast. The velocity of the PDC, obtained from the images of the SCT camera along the uppermost 250 m distance travelled along the SdF, was estimated at~20 m s −1 , which is in the range of the values obtained for the events occurring at Stromboli in March-April 2020 [44]. The PDC reached the coast after 42 s, as detected from the SPCT camera, travelling the 1028 m of the slope at an average speed of~25 m s −1 , and then expanded over the sea surface for about 250 m. The event lasted 54 s, and the ash plume observed from SPCT rose to about 690 m above the craters (Table 4).…”

“…For those occurring during lava flow output, Calvari et al [43] proposed calculating the daily erupted volume, suggesting that the drainage of degassed lava from the upper conduit could trigger the decompression and rise of the gas-rich LP magma from the source region causing the paroxysm. Paroxysms are often accompanied by the formation of hot avalanches or pyroclastic density currents (PDCs) spreading along the SdF slope and over the sea surface [29,42,44,45], thus having the potential to impact not just the island, but also boats sailing close to the coast. More rarely, PDCs may affect the other slopes of the island, such as occurred after the 1930 and 1944 paroxysms [12,46].…”

“…More rarely, PDCs may affect the other slopes of the island, such as occurred after the 1930 and 1944 paroxysms [12,46]. PDCs are caused by the opening of flank fissures [42,47,48], by the collapse of eruptive columns during paroxysms [41], by the collapse of small portions of the summit cone [49], by flank failure [50], or by the brecciation of lava flow fronts along the steep and incoherent SdF slope [29][30][31]42,44].…”

The short life of the volcanic island New Late’iki (Tonga) analyzed by multi-sensor remote sensing data

“… 15 ). The high temporal resolution data from geostationary satellites such as the Geostationary Operational Environmental Satellite (GOES), Meteosat (with the Spinning Enhanced Visible and InfraRed Imager SEVIRI sensor) and Multifunctional Transport Satellites (MTSAT) were used by 16 , 17 as well as by 18 , 19 (HOTSAT system) 20 , (HOTVOLC system) and 21 (RST VOLC ) among others, to analyse volcanic activity in near real-time.…”

“…High-resolution optical satellite imagery is ideally suited for the detailed analysis of, for example, lava flows and pyroclastic density currents (e.g. 18 , 25 , 30 , 31 ).…”