We investigate the 19 September 2021 eruption of the Cumbre Vieja volcano (La Palma, Canary Islands, Spain). In particular, we analyze the Differential Interferometric Synthetic Aperture Radar ...(DInSAR) measurements obtained by processing Sentinel‐1 images acquired from both ascending and descending orbits. First, we show the importance, for oceanic islands like La Palma, of investigating DInSAR products retrieved from time series, instead of single interferograms, to effectively remove possible atmospheric artifacts within the displacement measurements. Subsequently, we invert the retrieved data through analytical modeling. Our results highlight that a sill–like source was active in the pre–eruptive phase (8–16 September), whereas the action of two dikes prevailed during the co‐eruptive phase (17–22 September). This evolution suggests a process of magma rising through a network of interconnected sills and dikes. The seismicity, that preceded and accompanied the onset of the eruption, is consistent with our findings.
Plain Language Summary
Since 19 September 2021, an intense eruptive activity has begun at Cumbre Vieja volcano (La Palma, Canary archipelago, Spain), causing huge social and economic damage. The eruption was preceded and accompanied by numerous phenomena, such as gas emissions and seismic activity. In this work, we exploit the Differential Interferometric Synthetic Aperture Radar (DInSAR) measurements, obtained by processing Sentinel‐1 images, to quantify the retrieved pre‐ and co‐eruptive deformation patterns. In particular, this eruption provided us the opportunity to show the importance, for oceanic islands like La Palma, of investigating DInSAR products retrieved from time series, instead of conventional single interferograms, to effectively remove possible atmospheric artifacts within the displacement measurements. Subsequently, we invert the retrieved surface deformation measurements to investigate the geometries of the volcanic sources responsible for the observed deformations. Our results show the evolution of this eruptive phenomenon from the pre‐to the co‐eruptive phases, suggesting that a complex network of sills and dikes has allowed the magma rising. Moreover, our findings are in good agreement with the recorded seismicity and several geophysical evidence.
Key Points
We retrieve the pre‐ and co‐eruptive deformation patterns of Cumbre Vieja volcano through an advanced processing of Sentinel‐1 radar data
We show that a sill‐like source was active in the pre‐eruptive phase, whereas the action of two dikes prevailed in the co‐eruptive one
The retrieved sources are consistent with magma rising through a network of interconnected sills and dikes, and the seismicity evolution
This is a seven-year study (1/7/2011-31/12/2017) of radon monitoring at two sites of Campi Flegrei caldera (Neaples, Southern Italy) that in the last 70 years experienced repeated phases of volcanic ...unrest. The sites are equipped with devices for radon detection, based on the spectrometry analysis of the α-particles of radon daughters. A hybrid method, as combination of three known methods, is applied for the identification of residuals (anomalies) and trends of the time series of Radon. The results are compared with the following indicators of current caldera unrest: the tremor caused by the major fumarolic vent registered by a seismic station; the cumulative of background seismicity; the maximum vertical deformation acquired by GPS networks during the current phase of uplift; the temperature-pressure of the hydrothermal system estimated based on gas geo-indicators. The comparisons show strong correlation among independent signals and suggest that the extension of the area affected by current Campi Flegrei crisis is larger than the area of seismicity and of intense hydrothermal activity from which the radon stations are 1-4 km away. These results represent an absolute novelty in the study of a such calderic area and mark a significant step forward in the use and interpretation of the radon signal.
The knowledge of the dynamic of the Campi Flegrei calderic system is a primary goal to mitigate the volcanic risk in one of the most densely populated volcanic areas in the world. From 1950 to 1990 ...Campi Flegrei suffered three bradyseismic crises with a total uplift of 4.3 m. After 20 years of subsidence, the uplift started again in 2005 accompained by a low increment of the seismicity rate. In 2012 an increment in the seismic energy release and a variation in the gas composition of the fumaroles of Solfatara (in the central area of the caldera) were recorded. Since then, a slow and progressive increase in phenomena continued until today. We analyze the INGV - Osservatorio Vesuviano seismic catalogue of Campi Flegrei from 2000 to 2020 in order to look for any variation in the seismic parameters and compare them with geochemical monitored ones. A remarkable correlation between independent variables of earthquake cumulative number, CO/CO
values and vertical ground deformation reveals a likely common origin. Moreover the correlation between all the variables here analysed enlightens that the same origin can cause the temporal behavior of all these variables. We interpret the seismological, geochemical and geodetic observable in terms of the injection of magmatic fluids into the hydrothermal system or its pressurization.
La Fossa Caldera at Vulcano (Italy) has been showing signs of unrest since September 2021. To investigate this phenomenon, we conducted an analysis of geodetic and seismological data from July to ...December 2021. In particular, we analyzed Multi Temporal Interferometric Synthetic Aperture Radar and Global Navigation Satellite System data, showing a pronounced elliptical uplift signal, which we elaborated using analytical source modeling. Additionally, seismic data were used to identify seismicity associated with hydrothermal system activity and assess its temporal evolution. The results indicate that the observed deformation is consistent with the expansion of the hydrothermal system within the La Fossa Caldera. These findings align with the analysis of seismic data, revealing signals indicative of hydrothermal activity, such as Very Long Period events. The results suggest that the ongoing phenomenon since 2021 represents a hydrothermal unrest, similar to the one observed during the late 1970s to early 1990s.
Plain Language Summary
La Fossa Caldera at Vulcano Island, part of the Aeolian Islands archipelago in Italy, has shown an increased volcanic activity since September 2021. This activity is characterized by an increase in fumarole temperatures, massive gas emissions, as well as a marked uplift of the crater area, accompanied by an increase in seismicity. To investigate the nature of these phenomena, an analysis of ground deformation data obtained from Multi Temporal Interferometric Synthetic Aperture Radar and Global Navigation Satellite System measurements is presented. Additionally, a detailed analysis of data recorded by the seismic network on Vulcano Island has been conducted. The results indicate that these anomalies can be attributed to the expansion of the hydrothermal system, a phenomenon previously observed in the late 1970s and early 1990s.
Key Points
Multi Temporal Interferometric Synthetic Aperture Radar enabled investigating localized ground deformation in the La Fossa Caldera
The analysis of local seismicity indicates it is associated with the injection of fluids into conduit‐like structures
The modeled source of ground deformation associated with the 2021 unrest is consistent with the pressurization of the hydrothermal system
This paper reports the analysis of soil 222Rn data recorded over 7-years in the volcanic caldera of Campi Flegrei (Naples-Italy). The relationship between Radon activity concentration and several ...geophysical, geochemical and meteorological parameters, influencing the gas emissions, is estimated by the Artificial Neural Network (ANN) method. The analysis goals are: the estimation (replication) of the Radon time series from influencing parameters, the forecasting of an unknown part of it, and the search for anomalies. Results prove: (i) the effectiveness of the ANN method; (ii) Radon follow the periods of agitation of the caldera, demonstrated by the comparison with previous works using different methods.
•Radon time series at Campi Flegrei volcanic caldera is analysed.•Radon is estimated by Artificial Neural Network trained with influencing parameters.•The forecasting of an unknown part and the anomalies detection are performed.•The results prove high performance in estimation and forecasting of Radon signal.•Present anomalies coincide with anomalies obtained in papers using a different method.
The causative source of the first damaging earthquake instrumentally recorded in the Island of Ischia, occurred on 21 August 2017, has been studied through a multiparametric geophysical approach. In ...order to investigate the source geometry and kinematics we exploit seismological, Global Positioning System, and Sentinel‐1 and COSMO‐SkyMed differential interferometric synthetic aperture radar coseismic measurements. Our results indicate that the retrieved solutions from the geodetic data modeling and the seismological data are plausible; in particular, the best fit solution consists of an E‐W striking, south dipping normal fault, with its center located at a depth of 800 m. Moreover, the retrieved causative fault is consistent with the rheological stratification of the crust in this zone. This study allows us to improve the knowledge of the volcano‐tectonic processes occurring on the Island, which is crucial for a better assessment of the seismic risk in the area.
Key Points
Investigation of the ground deformation and source geometry of the 2017 Ischia Island earthquake (Italy) is discussed
The available seismological, GPS, and DInSAR data permit to investigate the causative fault and define its geometry and kinematics
The results suggest that the rheology properties of the crust beneath the Ischia Island have an influence on the volcano‐tectonic processes
Volcanoes in Italy and the role of muon radiography D'Alessandro, Raffaello; Ambrosino, F; Baccani, G ...
Philosophical transactions of the Royal Society of London. Series A: Mathematical, physical, and engineering sciences,
12/2018, Letnik:
377, Številka:
2137
Journal Article
Recenzirano
Odprti dostop
Cosmic-ray muon radiography (muography), an imaging technique that can provide measurements of rock densities within the top few 100 m of a volcanic cone, has now achieved a spatial resolution of the ...order of 10 m in optimal detection conditions. Muography provides images of the top region of a volcano edifice with a resolution that is considerably better than that typically achieved with other conventional methods (i.e. gravimetric). We expect such precise measurements, to provide us with information on anomalies in the rock density distribution, which can be affected by dense lava conduits, low-density magma supply paths or the compression with the depth of the overlying soil. The MUon RAdiography of VESuvius (MURAVES) project is now in its final phase of construction and deployment. Up to four muon hodoscopes, each with a surface of roughly 1 m
, will be installed on the slope of Vesuvius and take data for at least 12 months. We will use the muographic profiles, combined with data from gravimetric and seismic measurement campaigns, to determine the stratigraphy of the lava plug at the bottom of the Vesuvius crater, in order to infer potential eruption pathways. While the MURAVES project unfolds, others are using emulsion detectors on Stromboli to study the lava conduits at the top of the volcano. These measurements are ongoing: they have completed two measurement campaigns and are now performing the first data analysis.This article is part of the Theo Murphy meeting issue 'Cosmic-ray muography'.
We have analyzed a multiparametric data set of seismological, geodetic and geochemical data recorded at Campi Flegrei caldera since 1982. We focus here on the period 1989–2010 that followed the last ...bradyseismic crisis of 1982–1984. Since then, there have been at least five repeated minor episodes of ground uplift accompanied by seismicity. We have reanalyzed old paper and digital seismic data sets dating back to 1982. The paper recordings show evidence of long‐period events in January 1982 and March 1989, and we have digitized some of these significant waveforms. Furthermore, the revision of digital seismograms dating back to 1994 shows a significant swarm of long‐period events in August 1994. Volcano‐tectonic and long‐period events hypocenters have been relocated in a three‐dimensional velocity model. Statistical analysis of volcano‐tectonic seismicity shows many similarities and few differences between 1982–1984 and the following period 1989–2010. Long‐period waveforms have been analyzed using spectral analysis, which shows a grouping into three macrofamilies. Similarities in the seismic signature of episodes of minor uplift suggest that they originate from the injection of fluids into the deep part of a geothermal reservoir (about 2.5 km depth) and in its transfer toward a shallower part (about 0.75 km depth). Most of the observed geophysical signals are related to this second phase. The evidence consists of spatial and temporal connections between the ground deformation, long‐period and volcano‐tectonic seismicity and changes in the geochemical parameters of fumaroles. In this study we focused our analysis on two uplift episodes observed in 2000 and 2006. The joint inversion of Differential Synthetic Aperture Radar (DInSAR) and tiltmeter data show that during these periods the ground deformation was generated by at least two distinct sources located at different depths, with the shallower activated in the later stages of the uplift episodes. Our interpretation of the recent dynamics of Campi Flegrei is that the deep part of the geothermal reservoir inflates in response to mass and heat input from a magmatic source. When the pressure exceeds a threshold, fluids starts to migrate into the shallower part. During this transfer, long‐period sources are activated in response to the fluid motion. The gradual diffusion of fluids in the surrounding rocks lowers the resistance of a pervasive fracture system generating shallow microseismicity. Finally, fluids reach the surface, which gives a distinct geochemical signature to the overlying fumaroles.
Key Points
Campi Flegrei geothermal system is composed of at least two parts
Fluid flow in the geothermal system is the main source of seismicity
Geochemical and geophysical signals correlate in a common framework
Bearing in mind the destructive potential of tsunamis induced by volcanic landslides, the tsunamigenic event occurring at Stromboli volcano in Italy on 30 December 2002 has been re-examined here, by ...means of visible images and slope stability analysis. This was one of the few examples in the world of a flank collapse occurring at a volcano that was directly observed. We present the results of stability analyses, together with a sequence of photos collected from a helicopter a few minutes before the collapse. The result of this study is that the sequence of landslides triggering the 2002 Stromboli tsunami can be defined as the final stage of a lateral magma intrusion that exerted a high thrust at high altitude, destabilizing the entire slope. This study allows a more complete understanding of the event that took place on Stromboli on 30 December 2002. Furthermore, the approach used here, if appropriately modified, can be used in other contexts, contributing to the understanding of the condition that leads to tsunamigenic landslides.
Within a general volcanic unrest in the densely urbanized area of Campi Flegrei caldera (Italy) an increase in the activity of Pisciarelli hydrothermal area is occurring. The seismic amplitude of ...Pisciarelli fumarolic tremor is a proxy for the fluid emission rate of the entire Solfatara‐Pisciarelli hydrothermal system. The long‐term analysis indicates a significant increase, by a factor of ~3 of the fumarolic tremor amplitude since May 2017. This increment matches with the trend of geochemical and seismic parameters observed in Campi Flegrei, therefore highlighting that Pisciarelli is a key site to monitor the volcanic unrest underway in this high‐risk caldera. The analysis of data from three closely spaced seismic stations provided new clues about the source mechanism of the tremor. Analyzing the fumarolic tremor amplitude we could also identify an episode of enlargement of the emission area close to the main fumarole of Pisciarelli. We propose a monitoring system based on the fumarolic tremor analysis, which provides real‐time information on the Pisciarelli hydrothermal activity and therefore on the current unrest in Campi Flegrei caldera.
Key Points
Fumarolic tremor indicates a new increase of the Pisciarelli hydrothermal activity linked to the current large‐scale unrest at Campi Flegrei
The fumarolic tremor analysis allowed us to identify an episode of enlargement of Pisciarelli mud emissions
We propose a method for monitoring the hydrothermal system based on proximal measurements of fumarolic tremor
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