A Review of Variations in Magnetic and Pulsed Electromagnetic Fields for Earthquake Forecasting
Аннотация
This study analyzes geomagnetic and electromagnetic anomalies recorded in seismically active regions of Uzbekistan before, during, and after significant earthquakes, including Tavaksay (1977), Nazarbek (1980), Gazli (1976), Chimion (1982), Alay (1978), and others. Based on data obtained from geodynamic test sites (Tashkent, Charvak, East Fergana), four types of geomagnetic field anomalies were identified: long-term, medium-term, short-term, and post-seismic. Our research established stable correlations between the dynamics of the geomagnetic field and the processes of seismic event preparation. It was found that precursor geomagnetic anomalies can manifest 2–3 years before an earthquake, reflecting stages of tectonic stress accumulation. The shape and amplitude of anomalies depend on the distance to the epicenter, which opens possibilities for mapping focal zones. Distortions of bay-shaped magnetic field variations are considered indicators of local physico-mechanical changes in the Earth's crust, while post-seismic deviations serve as markers of relaxation processes in the earthquake focus. The work includes an analysis of anomalous variations in magnetic and impulse electromagnetic fields identified through long-term observations and proposes empirical relationships between magnitude and time, as well as magnitude and distance. A geophysical model of earthquake preparation was developed, along with methodological recommendations for improving forecasting systems. The obtained results contribute to enhancing the effectiveness of predicting the location, timing, and strength of upcoming earthquakes and expand scientific understanding of the electromagnetic manifestations of seismicity. This study significantly advances the development of seismology and geophysical field monitoring by offering new approaches to early seismic hazard warning.