scholarly journals Water Vapor Tomography of the Lower Atmosphere from Multiparametric Inversion: the Mt. Etna Volcano Test Case

2021 ◽  
Vol 8 ◽  
Author(s):  
Massimo Aranzulla ◽  
Claudia Spinetti ◽  
Flavio Cannavò ◽  
Vito Romaniello ◽  
Francesco Guglielmino ◽  
...  
Keyword(s):  
Water Vapor ◽  
Ground Deformation ◽  
Spatial And Temporal Variability ◽  
Atmospheric Effects ◽  
Etna Volcano ◽  
Atmospheric Effect ◽  
Atmospheric Anomaly ◽  
Mt Etna ◽  
Tropospheric Delays ◽  
Deformation Measurements

Space techniques based on GPS and SAR interferometry allow measuring millimetric ground deformations. Achieving such accuracy means removing atmospheric anomalies that frequently affect volcanic areas by modeling the tropospheric delays. Due to the prominent orography and the high spatial and temporal variability of weather conditions, the active volcano Mt. Etna (Italy) is particularly suitable to carry out research aimed at estimating and filtering atmospheric effects on GPS and DInSAR ground deformation measurements. The aim of this work is to improve the accuracy of the ground deformation measurements by modeling the tropospheric delays at Mt. Etna volcano. To this end, data from the monitoring network of 29 GPS permanent stations and MODIS multispectral satellite data series are used to reproduce the tropospheric delays affecting interferograms. A tomography algorithm has been developed to reproduce the wet refractivity field over Mt. Etna in 3D, starting from the slant tropospheric delays calculated by GPS in all the stations of the network. The developed algorithm has been tested on a synthetic atmospheric anomaly. The test confirms the capability of the software to faithfully reconstruct the simulated anomaly. With the aim of applying this algorithm to real cases, we introduce the water vapor content measured by the MODIS instrument on board Terra and Aqua satellites. The use of such data, although limited by cloud cover, provides a two-fold benefit: it improves the tomographic resolution and adds feedback for the GPS wet delay measurements. A cross-comparison between GPS and MODIS water vapor measurements for the first time shows a fair agreement between those indirect measurements on an entire year of data (2015). The tomography algorithm was applied on selected real cases to correct the Sentinel-1 DInSAR interferograms acquired over Mt. Etna during 2015. Indeed, the corrected interferograms show that the differential path delay reaches 0.1 m (i.e. 3 C-band fringes) in ground deformation, demonstrating how the atmospheric anomaly affects precision and reliability of DInSAR space-based techniques. The real cases show that the tomography is often able to capture the atmospheric effect at the large scale and correct interferograms, although in limited areas. Furthermore, the introduction of MODIS data significantly improves by ∼80% voxel resolution at the critical layer (1,000 m). Further improvements will be suitable for monitoring active volcanoes worldwide.

scholarly journals Finite element analysis of ground deformation due to dike intrusion with applications to Mt. Etna volcano

2009 ◽  
Vol 47 (5) ◽  
Author(s):  
A. Occhipinti Amato ◽  
M. Elia ◽  
A. Bonaccorso ◽  
G. La Rosa
Keyword(s):  
Ground Deformation ◽  
Near Field ◽  
Elastic Half Space ◽  
Etna Volcano ◽  
Element Analysis ◽  
Dike Intrusion ◽  
Dislocation Models ◽  
Mt Etna ◽  
Realistic Topography ◽  
2001 Eruption

A 2D finite elements study was carried out to analyse the effects caused by dike intrusion inside a heterogeneous medium and with a realistic topography of Mt. Etna volcano. Firstly, the method (dimension domain, elements type) was calibrated using plane strain models in elastic half-spaces; the results were compared with those obtained from analytical dislocation models. Then the effects caused both by the topographic variations and the presence of multi-layered medium on the surface, were studied. In particular, an application was then considered to Mt. Etna by taking into account the real topography and the stratification deduced from seismic tomography. In these conditions, the effects expected by the dike, employed to model the 2001 eruption under simple elastic half-space medium conditions, were computed, showing that topography is extremely important, at least in the near field.

scholarly journals Ground Deformation Detected by Permanent Tiltmeters on Mt. Etna Summit: The August 23-26, 2018, Strombolian and Effusive Activity Case

2019 ◽  
Vol 2019 ◽  
pp. 1-10
Author(s):  
Salvatore Gambino ◽  
Marco Aloisi ◽  
Giuseppe Di Grazia ◽  
Giuseppe Falzone ◽  
Angelo Ferro ◽  
...  
Keyword(s):  
Ground Deformation ◽  
Volcanic Tremor ◽  
Mount Etna ◽  
Etna Volcano ◽  
Strombolian Activity ◽  
Summit Area ◽  
Effusive Activity ◽  
Ground Deformations ◽  
Mt Etna ◽  
Set Up

Over the last few years, three tilt deep stations (27-30 meters) have been set up in the summit area of Mount Etna volcano. The aim of this challenging project is to record the ground deformations of the summit craters activity with high precision. We considered data related to the August 23-26, 2018, Strombolian and effusive activity. In this case, tiltmeters recorded variations in the order of 10−7 radians, not observed at the other stations. These changes suggest a shallow contraction source just south of the Southeast Crater. This result, related to the volcanic tremor source, points to the presence of a gas/magma reservoir feeding the Strombolian activity at 1200 m above sea level.

scholarly journals Tracking Magma Storage: New Perspectives From 40 Years (1980–2020) of Ground Deformation Source Modeling on Etna Volcano

2021 ◽  
Vol 9 ◽  
Author(s):  
Alessandro Bonaccorso ◽  
Marco Aloisi
Keyword(s):  
Ground Deformation ◽  
Deformation Source ◽  
Mitigation Strategies ◽  
Magma Storage ◽  
Etna Volcano ◽  
Source Modeling ◽  
Magma Reservoirs ◽  
Mt Etna ◽  
First Time ◽  
Over Time

A key issue on active volcanoes is to investigate the position and characteristics of the magma reservoirs over time. The aim is to better understand the crustal magma transfer, therefore also to define the volcanic hazard and plan the mitigation strategies. Mt. Etna volcano is characterized by a lively eruptive activity with frequent major flank eruptions that can be both purely effusive and explosive-effusive. This volcano has been monitored over 40 years by ground deformation measurements. The studies and modeling of the eruptive processes through these data have mainly concerned single eruptions and the recharge phases that preceded them. In this study, for the first time, we present four decades of numerous recharge periods modeled over time by using the same typology of measurements (geodetic baselines) and the same modeling method. This uniform approach enables tracking the location of magma storage in a robust and unambiguous way during its recharging, which causes the volcano to inflate. In particular, the recharging periods that preceded the main eruptive activities were investigated. The tracking of the source positions contributes to update the representation of the shallow-intermediate plumbing system (last 10 km). Moreover, as a new result, we highlight that the recharges preceding the explosive eruptions are accompanied by a deepening over time of the centroid of the pressure source. This result opens up new scenarios on the relationship between the position of the recharging storage and the subsequent eruptive style.

scholarly journals Utilization of WRF 3D Meteorological Data to Calculate Slant Total Delay for InSAR Atmospheric Correction

2021 ◽  
Author(s):  
Xinyi Wang ◽  
Qiming Zeng ◽  
Jian Jiao
Keyword(s):  
Water Vapor ◽  
Surface Deformation ◽  
Numerical Models ◽  
Atmospheric Correction ◽  
Three Dimensions ◽  
Small Scale ◽  
Horizontal Gradient ◽  
Atmospheric Effects ◽  
Total Delay ◽  
Atmospheric Effect

AbstractThe atmosphere introduces excess delays into the synthetic aperture radar (SAR) signal trajectory, especially in the troposphere. InSAR atmospheric correction methods include the use of SAR data and external water vapor products. The latter is more effective. However, since the removal of atmospheric effects should use atmospheric delay products in the direction of the line of sight (LOS), it is necessary to convert the zenith total delay to slant delay in the LOS direction. Conventionally, the zenith delay is divided by the cosine of the average incident angles to obtain slant phase delays. But this method could cause large errors because it ignores the atmospheric horizontal gradient change and the small-scale vertical structure. These problems can be solved by using three-dimensional atmospheric data simulated by numerical models, especially in the case of intense weather changes or complex terrain. However, few scholars paid attention to the application into InSAR atmospheric correction, because of the computation complexity and low efficiency. As the requirement for higher accuracy and the introduction of large errors caused by increasing incidence angles, it is significantly imperative to make the utmost of this method. Weather Research Forecast (WRF) model can provide the precipitate water vapor (PWV) and refraction index at different levels in the three dimensions, and then the slant total delay can be obtained for removing the atmospheric effect on the InSAR process. The results demonstrate that using 3D data can obtain more accurate slant total delay and improve the accuracy of surface deformation from InSAR technology.

scholarly journals Anatomy of a Paroxysmal Lava Fountain at Etna Volcano: The Case of the 12 March 2021, Episode

2021 ◽  
Vol 13 (15) ◽  
pp. 3052
Author(s):  
Sonia Calvari ◽  
Alessandro Bonaccorso ◽  
Gaetana Ganci
Keyword(s):  
Lava Flow ◽  
Ground Deformation ◽  
Monitoring Network ◽  
Lava Flows ◽  
Etna Volcano ◽  
Lava Fountain ◽  
Eruptive Episode ◽  
Lava Fountains ◽  
Borehole Strainmeter ◽  
Ash Plume

On 13 December 2020, Etna volcano entered a new eruptive phase, giving rise to a number of paroxysmal episodes involving increased Strombolian activity from the summit craters, lava fountains feeding several-km high eruptive columns and ash plumes, as well as lava flows. As of 2 August 2021, 57 such episodes have occurred in 2021, all of them from the New Southeast Crater (NSEC). Each paroxysmal episode lasted a few hours and was sometimes preceded (but more often followed) by lava flow output from the crater rim lasting a few hours. In this paper, we use remote sensing data from the ground and satellite, integrated with ground deformation data recorded by a high precision borehole strainmeter to characterize the 12 March 2021 eruptive episode, which was one of the most powerful (and best recorded) among that occurred since 13 December 2020. We describe the formation and growth of the lava fountains, and the way they feed the eruptive column and the ash plume, using data gathered from the INGV visible and thermal camera monitoring network, compared with satellite images. We show the growth of the lava flow field associated with the explosive phase obtained from a fixed thermal monitoring camera. We estimate the erupted volume of pyroclasts from the heights of the lava fountains measured by the cameras, and the erupted lava flow volume from the satellite-derived radiant heat flux. We compare all erupted volumes (pyroclasts plus lava flows) with the total erupted volume inferred from the volcano deflation recorded by the borehole strainmeter, obtaining a total erupted volume of ~3 × 106 m3 of magma constrained by the strainmeter. This volume comprises ~1.6 × 106 m3 of pyroclasts erupted during the lava fountain and 2.4 × 106 m3 of lava flow, with ~30% of the erupted pyroclasts being remobilized as rootless lava to feed the lava flows. The episode lasted 130 min and resulted in an eruption rate of ~385 m3 s−1 and caused the formation of an ash plume rising from the margins of the lava fountain that rose up to 12.6 km a.s.l. in ~1 h. The maximum elevation of the ash plume was well constrained by an empirical formula that can be used for prompt hazard assessment.

scholarly journals Combining High- and Low-Rate Geodetic Data Analysis for Unveiling Rapid Magma Transfer Feeding a Sequence of Violent Summit Paroxysms at Etna in Late 2015

2021 ◽  
Vol 11 (10) ◽  
pp. 4630
Author(s):  
Alessandro Bonforte ◽  
Flavio Cannavò ◽  
Salvatore Gambino ◽  
Francesco Guglielmino
Keyword(s):  
Ground Deformation ◽  
High Rate ◽  
Rate Data ◽  
Scale Analysis ◽  
Feeding System ◽  
Magma Sources ◽  
Mt Etna ◽  
Multi Temporal ◽  
Gnss Measurements ◽  
Low Rate

We propose a multi-temporal-scale analysis of ground deformation data using both high-rate tilt and GNSS measurements and the DInSAR and daily GNSS solutions in order to investigate a sequence of four paroxysmal episodes of the Voragine crater occurring in December 2015 at Mt. Etna (Italy). The analysis aimed at inferring the magma sources feeding a sequence of very violent eruptions, in order to understand the dynamics and to image the shallow feeding system of the volcano that enabled such a rapid magma accumulation and discharge. The high-rate data allowed us to constrain the sources responsible for the fast and violent dynamics of each paroxysm, while the cumulated deformation measured by DInSAR and daily GNSS solutions, over a period of 12 days encompassing the entire eruptive sequence, also showed the deeper part of the source involved in the considered period, where magma was stored. We defined the dynamics and rates of the magma transfer, with a middle-depth storage of gas-rich magma that charges, more or less continuously, a shallower level where magma stops temporarily, accumulating pressure due to the gas exsolution. This machine-gun-like mechanism could represent a general conceptual model for similar events at Etna and at all volcanoes.

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