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We propose a novel multidisciplinary approach to image the thermo‐rheological stratification beneath active volcanic areas, such as Long Valley Caldera (LVC). We performed a thermal fluid dynamic model via optimization procedure of the thermal conditions of the crust. We characterize the topology of the hot magmatic bodies and the hot fluid circulation (the permeable fault‐zones), using both a novel imaging of the a and b parameters of the Gutenberg‐Richter law and an innovative procedure analysis of P‐wave tomographic models. The optimization procedure provides the permeability of a reservoir (5.0 × 10−14 m2) and of the fault‐zone (5.0 · 10−14 – 1.0 × 10−13 m2), as well as the temperature of the magma body (750–800°C). The imaging of the rheological properties of the crust indicates that the brittle/ductile transition occurs about 5 km b.s.l. depth, beneath the resurgent dome. There are again deeper brittle conditions about 15 km b.s.l., agreeing with the previous observations. The comparison between the conductive and the conductive‐convective heat transfer models highlights that the deeper fluid circulation efficiently cools the volumes above the magmatic body, transferring the heat to the shallow geothermal system. This process has a significant impact on the rheological properties of the upper crust as the migration of the B/D transition. Our findings show an active magmatic system (6–10 km deep) and confirm that LVC is a long‐life silicic caldera system. Key Points: A novel multidisciplinary data fusion approach to image the thermo‐rheological stratification beneath active volcanic areasA novel imaging of the seismic a and b parameters and an innovative procedure analysis of P‐wave tomographic modelsWe highlighted the impact of fluid circulation on the rheological stratification of the crust beneath Long Valley Caldera [ABSTRACT FROM AUTHOR]

We investigate the 24–27 December 2018 eruption of Mount Etna occurred from fissures located on the volcano eastern flank and accompanied by a seismic swarm, which was triggered by the magma intrusion and continued for weeks after the end of the eruption. Moreover, this swarm involved some of the shallow volcano‐tectonic structures located on the Mount Etna flanks and culminated on 26 December with the strongest event (ML 4.8), occurred along the Fiandaca Fault. In this work, we analyze seismological data and Sentinel‐1 Differential Interferometric Synthetic Aperture Radar (DInSAR) measurements, the latter inverted through analytical modeling. Our results suggest that a dike source intruded, promoting the opening of the eruptive fissures fed by a shallower dike. Moreover, our findings indicate that the activation of faults in different sectors of the volcano may be considered as a response to accommodate the deformations induced by the magma volumes injection. Key Points: We investigate the ground displacements and the 3D source geometry of the December 2018 Mount Etna (Italy) volcano‐tectonic crisisDInSAR data obtained from SAR data pairs collected by Sentinel‐1 have been inverted through analytical modelingOur results suggest the presence of two volcanic sources: a shallow dike and a deeper one associated with a long‐term seismic swarm [ABSTRACT FROM AUTHOR]

Abstract: We investigate the L'Aquila 2009 earthquake (AQE, Mw 6.3, Italy) through a 3‐D Finite Element (FE) mechanical model based on the exploitation of ENVISAT DInSAR and GPS measurements and an independently generated fault model. The proposed approach mainly consists of (a) the generation of a 3‐D fault model of the active structures involved in the sequence and those neighboring to them, benefiting of a large geological and seismological data set; (b) the implementation of the generated 3‐D fault model in a FE environment, by exploiting the elastic dislocation theory and considering the curved fault geometry and the crustal heterogeneities information; and (c) the optimization of the seismogenic crustal blocks model parameters in order to reproduce the geodetic measurements. We show that our modeling approach allows us to well reproduce the coseismic surface displacements, including their significant asymmetric pattern, as shown by the very good fit between the modeled ground deformations and the geodetic measurements. Moreover, a comparative analysis between our FE model results and those obtained by considering a classical analytical (Okada) model, for both the surface displacements and the Coulomb stress changes, has been performed. Our model permits to investigate the coseismic stress and strain field changes relevant to the investigated volume and their relationships with the surrounding geological structures; moreover, it highlights the very good correlation with the seismicity spatial distribution. The retrieved stress field changes show different maxima: (a) at few kilometers depth, within the main event surface rupture zone; (b) at depths of 5–9 km in correspondence of main event hypocentral area, along the SW dipping Paganica Fault System (PFS); and (c) at depths of 12–14 km, in correspondence of the largest aftershock hypocentral area, along a steep segment of an underlying east dipping basal detachment. Moreover, the main event hypocenter is localized in a region of high‐gradient strain field changes, while a deeper volumetric dilatation lobe involves the largest aftershock zone. From these findings, we argue that the AQE hanging wall downward movement along the steep portion of PFS might have been modulated by the underlying basal detachment; on the other hand, the coseismic eastward motion of the PFS footwall might have triggered further slip on the OS, thus releasing the largest aftershock on an independent source. The retrieved stress and strain field changes, which support the active role of the OS, have been also validated through a comparative analysis with those obtained from independent geological, seismological, and GPS measurements. [ABSTRACT FROM AUTHOR]

Abstract: 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. [ABSTRACT FROM AUTHOR]

In recent years, a second generation of Synthetic Aperture Radar (SAR) satellite sensor has been designed and, partially, put into operation, leading to an important breakthrough in Earth Science studies. The common characteristics of such new systems are, indeed, a reduced revisit time (as short as a few days) and, in most cases, an improved spatial resolution (as small as a few meters), providing scientists with unprecedented data for the mapping and monitoring of natural and human-induced hazards. This paper provides an overview on the new observational capability offered by the second generation of SAR sensors, especially in the field of ground deformation analysis for mitigating the risk associated with natural and human-induced hazards. In particular, we exploit the high resolution X-band data acquired by the COSMO-SkyMed (CSK) constellation to show how deformation phenomena characterized by limited spatial extent and extremely fast dynamics can be detected and investigated in details. Whenever possible, we compare the achieved results with those obtained by using data collected by the first generation ERS-1/2 and ENVISAT systems. A comparison with one ALOS satellite dataset is also included. Most of the results, based on the application of Differential SAR Interferometry (DInSAR) techniques, highlight how this technology is not anymore just a sophisticated tool for remotely studying surface deformation phenomena, but it is becoming an operational system for near-real time deformation monitoring. Moreover, we also show how the improved spatial resolution extends the possibility to exploit SAR image amplitude, instead of phase, for direct comparison with optical data and for imaging large deformation episodes, typically associated with strong seismic events, for which DInSAR may fail. [ABSTRACT FROM AUTHOR]

We investigate the co-seismic effects of the Mw 7.8 Gorkha earthquake through a Finite Element modelling approach that jointly exploits space-borne DInSAR deformation measurements and geologic-structural information. Our model permits to retrieve the coseismic displacements with a very good accuracy and to confirm the finding of earlier studies suggesting that the slip reaches a maximum value of about 7 m at a depth of 7–15 km along the Main Himalayan Thrust (MHT) and occurs in an area about 30 km northern of Kathmandu. In particular, the main-shock ruptured the deep part of the seismogenic zone of MHT, with rather small displacement values retrieved along the splay faults (Main Frontal Thrust – MFT; Main Boundary Thrust – MBT) in the southern region. A relevant aspect of our results is the imaging of about 3 m of displacement in correspondence to the shallow portion of the Main Central Thrust (MCT) to the north and of the Munsiari/Mahabharat Thrust (MT) to the south; this finding may be associated to a possible mechanism for accommodating the MHT-sourced deformation on the adjacent thrusts, highlighting a passive role of the hinterland structures as receiver faults of the displacements transferred from earthquakes originating on the MHT. In addition, the proposed model allow us to map the stress field distribution (evaluated through von Mises failure criteria) associated to the main seismic event; this result is in good agreement with the hypocentral distribution and mechanism of the investigated aftershocks. [ABSTRACT FROM AUTHOR]

On Sept. 19th, 2021, the largest historical eruption on the island of La Palma began, which had a significant scientific, social, and economic impact. The 2021 Tajogaite eruption was characterised by short precursors, lasting only 8 days. The seismicity started on Sept. 11th with a westward and upward migration of hypocenters. Permanent GNSS stations started recording deformation on Sept. 12th on the island's western side, which reached more than 15 cm just before the eruption. After the eruption onset, the ground deformation increased, reaching a maximum on Sept. 22nd and showing a nearly steady deflation trend in the following months. To better understand the dynamics of the eruption, we exploited a joint dataset of GNSS and Sentinel-1 SBAS time series along both ascending and descending orbits. To obtain the geometry of the causative source of the ground deformation, we combined the result of a preliminary non-linear inversion and the precise location of the seismicity. The resulting geometry of the source is that of a twisted dike bending eastward. We performed inverse modelling to obtain the spatiotemporal kinematics of the opening function of the dike. The forward modelling has been realised using a 3D finite-element approach considering the island's topography. Our findings reveal a close correspondence between the magmatic intrusion and pre-eruptive seismicity. The ascent of the magma occurred along two branches, and the rheology of a previously identified ductile layer strongly affected the magma propagation process. Finally, we found evidence of an early shallow deformation, which we interpret as the effect of ascending hydrothermal fluids. Our findings highlight the need for advanced modelling to understand pre-eruptive processes in basaltic volcanoes., (© 2024. The Author(s).)

Long-term and high temporal resolution gravity and deformation data move us toward a better understanding of the behavior of Mt Etna during the June 1995 - December 2011 period in which the volcano exhibited magma charging phases, flank eruptions and summit crater activity. Monthly repeated gravity measurements were coupled with deformation time series using the Differential Synthetic Aperture Radar Interferometry (DInSAR) technique on two sequences of interferograms from ERS/ENVISAT and COSMO-SkyMed satellites. Combining spatiotemporal gravity and DInSAR observations provides the signature of three underlying processes at Etna: (i) magma accumulation in intermediate storage zones, (ii) magmatic intrusions at shallow depth in the South Rift area, and (iii) the seaward sliding of the volcano's eastern flank. Here we demonstrate the strength of the complementary gravity and DInSAR analysis in discerning among different processes and, thus, in detecting deep magma uprising in months to years before the onset of a new Etna eruption.