Modulation of Global Strong Earthquakes by Solar Activity Cycles: Evidence from Self-Comparison and Pressure Mechanism

This study adopts the self-comparison method to explore the intrinsic link between solar activity cycles and global strong earthquakes, focusing on revealing the regulatory role of solar activity in triggering major earthquakes. Two core regular patterns are identified: first, the solar maximum phase significantly inhibits the occurrence of major earthquakes by exerting continuous external pressure; second, the solar minimum phase removes this constraint, allowing the concentrated release of crustal stress. From a fluid mechanics perspective, solar activity exerts a direct regulatory effect on the Earth’s crustal stress state: the solar wind, as a high-speed plasma fluid, transfers pressure to the Earth’s surface, and the duration and intensity of this pressure directly determine the accumulation and release of crustal stress. A total of 5 global earthquakes with magnitudes ≥9.0 have been recorded so far, and all of them occurred during the solar minimum period (when solar activity is weak) rather than the maximum period. This strict corresponding relationship eliminates randomness and provides clear and reliable observational evidence for the "pressure holding-release" mechanism. This study uses long-term observational data (from 1900 to 2025) to verify that the occurrence of M≥9.0 earthquakes is entirely consistent with the solar activity cycle. Specifically, no M≥9.0 earthquakes have been recorded during the solar maximum phase, while all M≥9.0 earthquakes have occurred during the solar minimum phase or the declining phase of solar activity. This distribution pattern is not a random coincidence but is driven by the "pressure holding-release" mechanism based on fluid mechanics: the solar wind, as a high-speed plasma fluid, exerts continuous pressure on the Earth’s crust during the solar maximum phase, locking the fault zones and preventing stress release; when solar activity weakens (minimum phase), the external pressure decreases, the fault constraints are lifted, and the accumulated stress is released in the form of large earthquakes. This mechanism not only breaks the disciplinary isolation between astronomy and geophysics but also provides a clear and operable theoretical framework for earthquake prediction, with significant scientific and practical value.