Solar Activity, Galactic Cosmic Ray Variations, and the Global Seismicity of the Earth

A comparative analysis of the correlation between the number of strong (magnitude M ≥ 5.0), crustal (hypocenter depth 0 ≤ h ≤ 60 km) earthquakes per year ( N EQ/Year ), which reflects the global seismic activity of the Earth, and the total annual flux of solar radiation at the wavelength of 10.7 cm ( F 10.7 Year ), which integrally characterizes the solar activity level, is carried out for solar cycles 21–24. The statistically significant linear correlation coefficient is ρ( N EQ/Year , F 10.7 Year ) = –0.414. The correlation between N EQ/Year and the average annual variation in the galactic cosmic ray intensity δ Year is considered within the same time interval; in this case, ρ( N EQ/Year , δ Year ) = 0.459, which explains ~20% of the N EQ/Year changes within the linear single-factor model by δ Year changes. When the solar activity and the galactic cosmic ray intensity are considered as independent factors that form the seismic activity of the Earth, the strength of the link between the galactic cosmic ray intensity and the seismic activity of the Earth turns out to be greater than that between the solar activity and the seismic activity of the Earth within the studied time interval for an array of strong earthquakes with M ≥ 5.0. This moderate correlation may be due to the corresponding redistribution of pressure at the tropospheric level, which is associated with an increase in cloudiness and an increase in the galactic cosmic ray intensity during periods of low solar activity, which directly ionize the lower atmosphere layers and indirectly affect dynamic processes in them. In this case, there are changes in the global circulation regime in the troposphere that contribute to the activation of “matured” sources of strong earthquakes by the main baric structures of the atmosphere: cyclones and anticyclones.