Riccardo De Ritis

In October 2020, a low-magnitude earthquake struck near the village of Capena, approximately 30 kilometers north of Rome. This seismic event was particularly remarkable due to its shallow hypocenter and the complete absence of aftershocks. Additionally, both during and after the event, residents reported hearing loud rumbling noises on multiple occasions in the village and surrounding rural areas. The earthquake's epicenter is located in a sinkhole-prone region intersected by major infrastructure, including a high-speed railway, high-voltage power lines, and a provincial road. Given these conditions, public authorities and regional Civil Protection agency closely monitored the area, prompting a comprehensive investigation. The study adopted an interdisciplinary approach to assess the stability of sinkhole-prone zones and identify any geological changes potentially triggered by the earthquake. A key focus of the research was the "Lago Puzzo," a well-documented example of multiphase, still active, sinkhole evolution within the San Martino Valley, alongside other similar extinct features in the area. The investigation integrated three primary methodologies: spectral analysis of seismic data to characterize the October 2020 event; remote sensing (SAR) using InSAR analysis to map ground displacement; geophysical surveys (ERT) to reveal subsurface structures. Although the study found no direct correlation between the earthquake and the evolution of Lago Puzzo, the results provide valuable insights into the current deformation state of the sinkhole and offer projections for its potential future development. Ultimately, this research represents a significant step forward in refining hazard assessment methods for the region.

The Southeastern Tyrrhenian Sea is a back-arc basin characterized by the onset of volcanism over the past ~11 million years and the development of numerous volcanic seamounts. Hydrothermal venting is predominantly concentrated in the southeastern sector, encompassing the Aeolian volcanic arc and major volcanic edifices, such as Palinuro and Marsili. These systems frequently exhibit zones of localized magnetic depletion (demagnetization) within otherwise magnetized volcanic structures, often linked to hydrothermal alteration. Notably, volcanic rejuvenation phases are commonly associated with active hydrothermal circulation. In response to mounting ecological concerns, the Italian government has delineated extensive Ecological Protection Zones (EPZs), including those in the Eastern Tyrrhenian sector. These EPZs encompass a series of prominent seamounts—Palinuro, Marsili, Vercelli, Vavilov, Magnaghi, Enarete, and Anchise—that exhibit morphological evidence of rejuvenation and magnetic anomalies consistent with hydrothermal modification. Such features are indicative of potentially mineralized systems, relevant for future resource exploration. A comprehensive evaluation of both the ecological significance and the mineral potential of these areas is now imperative. Balancing environmental conservation with the strategic assessment of deep-sea mining prospects will be essential to mitigate biodiversity loss while promoting the sustainable use of marine mineral resources.

[Article in Italian] Tanto rumore per qualcosa: i misteriosi brontídi

Phlegraean Fields is a large, active caldera located in the densely populated westernmost sector of Naples’s Bay (Southern Italy). Several Bouguer anomaly surveys are available for this area with different resolution and accuracy; gravity data derive from the integration of stations placed below and above the sea level as the caldera develops both onshore and offshore. The comparison of these maps with the Digital Elevation Model shows a still remaining Terrain Effect hiding the shallower and deep caldera structure’s signal. This effect has an impact on the modelling of the gravity source’s depth and geometry. In this research, we apply a geologically constrained terrain correction method to the higher resolution Free Air dataset available for the study area to enhance the complete Bouguer reduction. The correlation analysis between the residual and the topography allows us to assess the quality of the outcomes. The results represent an improvement in the anomalies’ isolation and clearly show a continuous circular-like clustering of maxima related to the geometry of the caldera rim. The minima are associated with volcano-tectonic depression filled with pyroclastic and sediment. Furthermore, features alignments overlap the fault systems, along which the volcanic activity occurred.

Over 1 million volcanoes on the Earth surface occur in marine and submarine environments in different geodynamic contexts

We present the new high-resolution magnetic anomaly map of the La Fossa di Vulcano Caldera and Lipari active Volcanic Complex (Southern Italy), obtained by merging two low-altitude aeromagnetic surveys. Magnetic anomalies range from -600 to 2600 nT and have different characteristics moving from South to North. La Fossa di Vulcano Caldera is characterized by very high intensities and short wavelengths which align along the NW-SE and NS Tindari-Letojanni strike slip fault where the Southern part of the Aeolian Archipelago emplaced. The Lipari island is instead characterized by lower intensity anomalies elongated in the NE-SW direction of the subordinate faults. The Lipari area can be further subdivided into Northern and Southern zones with distinctive signatures. The Southern side is characterized by negative magnetic values whereas the central-Northern side by positive anomalies. This anomaly pattern is caused by the interplay among strike slip tectonics, chemistry of the uprising magmas and the still little-known effect of thermal setting, especially on the Lipari island. To support the interpretations, we applied a digital enhancement on the total intensity magnetic anomaly field and the spatial correlation analysis of the magnetic and volcano-tectonic features. The insights we obtained are helpful to better understand the relationship between the arc volcanism and the strike slip tectonics and to define new inferences useful to forecast future eruptions of the La Fossa Caldera active system. In fact, recent unrest signals were registered at La Fossa Cone which, together with Stromboli island, are the present-day active volcanoes of the Archipelago.

Volcanic islands are often affected by ground displacement such as slope instability, due to their peculiar morphology. This is the case of Ischia Island (Naples, Italy) dominated by the Mt. Epomeo (787 m a.s.l.), a volcano-tectonic horst located in the central portion of the island. This study aims to follow a long temporal evolution of ground deformations on the island through the interferometric analysis of satellite SAR data. Different datasets, acquired during Envisat, COSMO-SkyMed and Sentinel-1 satellite missions, are for the first time processed in order to obtain the island ground deformations during a time interval spanning 17 years, from November 2002 to December 2019. In detail, the multitemporal differential interferometry technique, named small baseline subset, is applied to produce the ground displacement maps and the associated displacement time series. The results, validated through the analysis and the comparison with a set of GPS measurements, show that the northwestern side of Mt. Epomeo is the sector of the island characterized by the highest subsidence movements (maximum vertical displacement of 218 mm) with velocities ranging from 10 to 20 mm/yr. Finally, the displacement time series allow us to correlate the measured ground deformations with the seismic swarm started with the Mw 3.9 earthquake that occurred on 21 August 2017. Such correlations highlight an acceleration of the ground, following the mainshock, characterized by a subsidence displacement rate of 0.12 mm/day that returned to pre-earthquake levels (0.03 mm/day) after 6 months from the event.