A study aimed at exploring the use of satellite data for the identification of magnetic signals potentially associated with the preparatory phase of some earthquakes has just been concluded.
Using measurements collected by the Swarm satellites, developed to monitor the Earth's magnetic field, Scientists have examined possible magnetic anomalies preceding some major seismic events.
In the study "Successful Tests on Detecting Pre-Earthquake Magnetic Field Signals from Space" just published in MDPI's Remote Sensing journal, the team of researchers fromNational Institute of Geophysics and Volcanology (INGV) andInstitute of Geophysics of Tehran University (IRAN), with funding from INGV-MUR (Unitary Project, Dynamic Planet), ASI (Limadou Science+ Project) and the University of Tehran, have analyzed 1077 significant earthquakes, which occurred between 2014 and 2023 in the tectonically active region of the Alpine-Himalayan belt.
"We developed and applied an automatic algorithm to analyze magnetic data recorded up to 10 days before each earthquake.", he claims Angelo De Santis, INGV associate researcher and corresponding author of the article. "The preliminary results have highlighted the presence of specific anomalies in the magnetic signals, allowing us to assume a correlation between the duration of these anomalies and the magnitude of the earthquakes: the higher the magnitude of the seismic event, the longer the duration of the magnetic anomaly detected by the satellite.".
Although accurate earthquake prediction remains elusive at present, research into earthquake precursors is an area of enormous interest and complexity.
Among the elements studied to understand a possible correlation, there are also some changes in the ionosphere, such as variations in the geomagnetic field measured by satellite.
However, such signals do not manifest themselves uniformly for all earthquakes, which presents significant challenges for their reliability and practical application.
"The method we have developed”, continues De Santis, “although both based on the analysis of magnetic anomalies ex post from the events, has shown a high presumptive capacity in the analyzed sample, with promising values of accuracy and precision".
However, the same scholars underline that false alarms are very present, which still constitute a significant limitation.
"During the study we conducted an in-depth analysis to test the robustness of the results.”, continues De Santis. “By changing the position of the epicenter, the system has no detected significant anomalies, suggesting that the applied method can be a good assumption of reliability".
This study represents a further step in the investigation of pre-earthquake signals and opens the way to new possibilities for understanding and monitoring seismic events also from space.
The research is part of a continuous development of monitoring tools and methodologies, with the aim of improving the reliability of seismic analyses and providing a more solid basis for future studies.
The authors, in fact, although aware of the current limitations of the method, hope that this work will contribute to improving the understanding of the behavior of earthquakes and of the coupling between the layer in which they occur, the lithosphere, and the upper layers of the atmosphere and ionosphere in the preparatory phase of earthquakes.
The next step will be to integrate these data with other environmental and geophysical parameters, coming from ground-based measurements and the atmosphere, to further refine the accuracy of the results.
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Figure 1. Earthquakes under study. The epicenters of earthquakes with a magnitude equal to or greater than 5.0 that occurred in the Alpine-Himalayan range from 2014 to 2023 are indicated (source: https://www.usgs.gov)
(image created with AI based on the location of the earthquakes studied)