Dedalo Marchetti

In this paper, Singular Spectral Analysis (SSA) is applied to the geomagnetic field to delineate signatures from different sources, such as geomagnetic variability and lithospheric processes. We performed SSA on the Y component of the Swarm satellite magnetic field By during the period from September 2023 to January 2024. Eigen values obtained through SSA were correlated with geomagnetic indices Ap and Dst. λ1 decreases during disturbed geomagnetic conditions (Ap > 20, Dst < −20 nT). Lower λ ₂ values occur during quiet conditions with stable Ap (−20 nT). The third eigenvalue (λ3) does not show a statistically significant correlation with the geomagnetic external source time series ( r = −0.005, p > 0.05), and is therefore used as a proxy for lithospheric processes. An earthquake of M7.6 occurred near the northern coast of Noto Peninsula on the west coast of Honshu, Japan on 1 January 2024. The temporal variation of the third eigenvalue λ3 from 120 days before the earthquake up to 30 days after it, shows a clear increase after the occurrence of Japan earthquake. A simultaneous anomaly of 0.5 nT in the first derivative of the Y component, 6 days before the earthquake supports the observed change in λ3. These anomalous changes in λ3 after the Japan earthquake support the correlation between anomalies extracted and the occurrence of earthquake aftershocks. Our analysis demonstrates that the SSA may be considered a promising tool for the extraction of anomalies associated with crustal activity.

The study of the preparation phase of earthquake occurrence is essential to better understand our planet and assess the seismic hazard (Marchetti et al., 2024). However, different approaches are generally provided without the possibility of a direct comparison. Consequently, even the nature of the extracted anomalies before an earthquake is the object of scientific discussion.In this work, we present SEISMO-VRE, a freely available tool available on GitHub (https://github.com/dedalomarchetti/SEISMO-VRE), developed as Jupyter Notebooks with Python or MATLAB kernels, to serve a broader user community following the open science paradigm. The tool performs several analyses of the lithosphere, atmosphere and ionosphere, extracting anomalies and trends for each geo-layer. It produces graphs and tables of the extracted anomalies and, in particular, a summary graph for the comparison of the trends in the lithosphere, atmosphere and ionosphere. suggesting potential interactions between Earth’s geo-layers.Data are retrieved from the European Plate Observing System (EPOS) Platform and integrated with NASA and ESA atmospheric and ionospheric data using a dedicated notebook that we provided in the same public GitHub repository.Given the ease of reproducibility of SEISMO-VRE across different case studies, we will present results in response to earthquakes and volcanic eruptions. Case studies will include the Italian Seismic sequence 2016 (M6.0 and M6.5 as larger events), the Turkey Marmara region 23 April 2025 M6.2 earthquake, the Etna volcano eruption on 3 December 2015 (Volcanic Explosive Index, VEI = 3) and other cases.Whenever it’s possible, we will also compare the results of the SEISMO-VRE with published papers to discuss the similarities and differences. Overall, we will provide a scientific discussion on the possible reasons for differences in the identified trends for different earthquakes. In fact, epicentre location (sea or land), focal mechanism, and magnitude appear to play a major role in the preparation phase of earthquakes.Finally, we propose this tool not only to provide a universal and shared framework for the multiparametric investigation of earthquakes, volcanic eruptions and other natural and anthropogenic hazards, but also to highlight the advantages of using the EPOS pan-European research Infrastructure platform. References:Marchetti, D., Bailo, D., Falcone, G., Michalek, J., Paciello, R., & Piscini, A. (2025a). GitHub. https://github.com/dedalomarchetti/SEISMO-VREMarchetti, D.; Bailo, D.; Michalek, J.; Paciello, R.; Falcone, G.; Piscini, A (2025b). A Multiparametric Investigation of an Earthquake by a Jupyter Notebook: The Case Study of the Amatrice-Norcia Italian Seismic Sequence 2016-2017. In Proceedings of the Computational Science and Its Applications – ICCSA 2025 Workshops; https://doi.org/10.1007/978-3-031-97657-5_19Marchetti, D.; Yuan, Y.; Zhu, K (2024. Editorial of Special Issue “Remote Sensing Observations to Improve Knowledge of Lithosphere–Atmosphere–Ionosphere Coupling during the Preparatory Phase of Earthquakes”. Remote Sens. 2024, 16, 1064. https://doi.org/10.3390/rs16061064

Solar activity and its sharp variability generally produce large-scale disturbances in Earth’s magnetosphere, inducing geomagnetic fluctuations that can be measured globally through ground-based magnetometers and Low Earth Orbit (LEO) satellite observations. These disturbances, driven primarily by solar wind variability and coronal mass ejections, may cause geomagnetic storms and induce electrical currents in Earth’s ionosphere and crust, leading to measurable electromagnetic signatures. Considering that both tectonic deformation and geomagnetic variations affect the physical state of Earth’s lithosphere (even though with different weights), possible links between solar-driven geomagnetic activity and seismic processes have been proposed in the literature.Preliminary analyses indicated that while geomagnetic storms produce large and well-defined electromagnetic perturbations in the Earth–ionosphere system and well-recorded by geomagnetic ground magnetometers, any corresponding modulation of seismicity is subtle and difficult to distinguish from background tectonic variability. Nonetheless, localised correlations in highly conductive, fluid-rich fault systems suggest that electromagnetic effects may contribute to earthquake timing in specific geological settings when faults are near the critical failure due to accumulated tectonic stress. Over the past several decades, a number of hypotheses have proposed that such geomagnetic disturbances could influence the timing of earthquake occurrence by modulating crustal stress, pore-fluid pressure, or electrochemical processes along active faults.This contribution emerged from the International Space Science Institute (ISSI) Team 23-583 (57) meeting activities, which proposed a new hypothesis of geomagnetic–seismic coupling where geomagnetic fluctuations generate electric currents within the conductive layers of the lithosphere. The hypothesis consists of electrolytic deposition of elements on fault surfaces due to telluric currents acting in lithospheric fluids, capable of weakening the cohesion between foot and hanging walls and consequently inducing slippage. Such a hypothesis is compared with others, including (1) Lorentz-force interactions between induced telluric currents and crustal rock masses, (2) electromagnetic triggering of electrokinetic fluid migration in fault zones, and (3) magnetoelastic effects in stressed, magnetically susceptible rocks. AcknowledgmentWe acknowledge ISSI (Bern) /ISSI-BJ (Beijing) for supporting the International Team 23-583 (57) “Investigation of the Lithosphere Atmosphere Ionosphere Coupling (LAIC) Mechanism before the Natural Hazards” led by Dedalo Marchetti and Essam Ghamry, and in particular, Prof. Dimitar Ouzounov for fruitful scientific discussions.

Swarm is a three-satellite mission operated by the European Space Agency to monitor the Earth’s magnetic field. The China Seismo-Electromagnetic Satellite (CSES) is a satellite dedicated to studying the possible seismo-induced effects of earthquake activity on the ionosphere, operated by the China National Space Administration in cooperation with the Italian Space Agency. Such satellites are placed in Low Earth Orbit at an altitude ranging from 460 km to 510 km. We selected orbital combinations with the Swarm satellite in one hemisphere and CSES-01 in the opposite one to study the impact of magnetic pulsations on the ionospheric environment. The data have been filtered in the frequency range of Pi2 pulsations (period between 40 s and 150 s). Similar oscillations of a few nanoTeslas of the magnetic field intensity were detected by both satellites, sometimes in phase and at other times in counterphase. Detected oscillations could be explained by interactions between the Sun’s and Earth’s magnetic fields or the effect of a satellite crossing the auroral ring currents at the Northern and Southern Poles. This work supports the cross-validation of magnetic data from multiple satellite missions in Low Earth Orbit, such as Swarm and CSES. Our results confirm the scientific reliability of magnetic data acquired from the above-cited satellite missions.

In this study, we analysed remote sensing data collected during the Beirut port explosion on 4 August 2020 at 15.08 UT. For this purpose, we selected three Low-Earth-Orbit (LEO) satellite missions that passed near the Beirut port explosion site immediately after the event. The satellites involved were Swarm-B, the Defence Meteorological Satellite Program (DMSP-F17), and the Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC-2). This study focused on identifying the possible ionospheric signatures of explosion in both hemispheres. The conjugate hemispheric points were traced using the International Geomagnetic Reference Field (IGRF) model. We found that the satellite data revealed disturbances not only over the explosion site in the Northern Hemisphere, but also in its corresponding conjugate region in the Southern Hemisphere. Ionospheric electron density disturbances were observed poleward in the conjugate hemispheres along the paths of the Swarm and DMSP satellites, whereas the magnetic field data from Swarm-B showed both equatorward and poleward disturbances. Additionally, the ionospheric disturbances detected by Swarm-B (18:52 UT) and DMSP-F17 (16:30 UT) at the same location suggested travelling ionospheric disturbance (TID) oscillations with identical spatial patterns for both satellites, whereas the disturbances observed by COSMIC-2 south of the explosion site (10°N) indicated the radial propagation of TIDs. COSMIC-2 not only recorded equatorward topside (>550 km) ionospheric electron density disturbances, but also in the conjugate hemispheres, which aligns with the time frame reported in previous studies. These ionospheric features observed by multiple LEO satellites indicate that the detected signatures originated from the event, highlighting the importance of integrating space missions for monitoring and gaining deeper insight into space hazards. The absence of equatorward ionospheric disturbances at the altitudes of DMSP-F17 and Swarm-B warrant further investigation.

In this study, we compared the results of multiparametric and multilayers investigations of three doublet earthquakes that occurred around the Arabian plate (M6.2 + M6.0 on 18 August 2014 close to Dehloran, Iran; M6.0 + M6.0 occurred on 15 July 2018 offshore Kilmia, Yemen and M6.0 + M6.0 occurred on 1 July 2022 close to Bandar-e Lengeh). We applied identical methods to the same dataset for all three cases. In particular, we investigated lithospheric, atmospheric, and ionospheric data six months before the three events. The lithosphere was investigated by calculating the cumulative Benioff strain with the USGS earthquake catalogue. Several atmospheric parameters (aerosol, SO2, CO, surface air temperature, surface latent heat flux humidity, and dimethyl sulphide) have been monitored using the homogeneous data from the MERRA-2 climatological archive. We used the three-satellite Swarm constellation for magnetic data, analysing the residuals after removing a geomagnetic model. All the cases present some patterns of anomalies, and when comparing them, we noticed some similarities but also differences. We pointed out that the released energy by the three events is very similar and occurred around the same plate. Still, they involved two different tectonic contexts (compressional on the Iranian side and extensional and transcurrent on the African Plate border). For the above reasons, their comparison is very interesting. Some similarities seem to be explainable in the tectonic context, and some are caused by the ocean's influence at the epicentre location. However, we also identified some differences that still require further investigation and comparison with other case studies.Finally, this work can be considered a preliminary test of an extensive investigation and systematical search of LAIC patterns before the earthquake occurrences and the study of the possible influence of focal mechanism, location, geological factors, and other constraints. References :Ghamry Essam; Marchetti Dedalo; Metwaly Mohamed. Geophysical Coupling Before Three Earthquake Doublets Around the Arabian Plate. Atmosphere 2024, 15, 1318. https://doi.org/10.3390/atmos15111318