Author(s)

Marilia Tavares, Anibal Azevedo

.

This paper inspects possible influence of solar cycles on earthquakes through of statistical analyses. We also discussed the mechanism that would drive the occurrence of increasing of earthquakes during solar maxima. The study was based on worldwide earthquakes events during approximately four hundred years (1600-2010).The increase of earthquakes events followed the Maxima of Solar cycle, and also depends on the tectonic plate location. From 1600 until 1645 events increased during the Maxima in some of the tectonic plates as Pacific, Arabian and South America. The earthquakes analyzed during two grand solar minima, the Maunder (1645-1720) and the Dalton (1790-1820) showed a decrease in the number of earth-quakes and the solar activity. It was observed during these minima a significant number of events at specific geological features. After the last minima (Dalton) the earthquakes pattern increased with solar maxima. The calculations showed that events increasing during solar maxima most in the Pacific, South America or Arabian until 1900. Since there were few records during these three centuries we needed addi-tional analysis on modern data. We took the last four solar cycles events (1950-2010) and made similar calculations. The results agreed with the former calculations. It might be that the mecha-nism for the Sun-Earth connection relies on the solar wind speed. In both records (1600-1900) and (1950-2010) the results showed a significant increase in earthquakes events in some of the tectonic plates linked to solar maxima. The So-lar wind energy striking the Earth’s magneto-sphere affects the entire environment because the pressure on the region increases and the magnetosphere shrinks sometimes four Earth’s radii. This sudden compression causes earth-quakes in specific plates. During the times of solar minima the pressure from the solar wind on the earth decreases, then the magnetosphere expands and earthquakes happen in a different pattern according to the geological feature on earth’s surface less frequently. Solar driven events include coronal mass ejections (CME) and coronal holes, which are at a maximum during the descending phase of solar activity. The tectonic are important because there is he-terogeneity in the crust and the tectonic stress depends on each region. The geo-effectiveness of solar wind from a coronal hole only depends on the position of the hole relative to the Earth and for the CMEs an additional factor is their velocity. The influence of these solar events could be detected from electromagnetic varia-tions on the ground prior the earthquakes. The goal in this research was to show the solar events influenced the earthquakes and seis-mologic events following some special display and also how the Sun’s activity played to make earthquakes increase. This paper discussed details of this mechanism, calculations and as-sociated factors.

Solar Cycles; Earthquakes; Currents; Geomagnetic

Tavares, M. and Azevedo, A. (2011) Influences of Solar Cycles on Earthquakes. Natural Science, 3, 436-443. doi: 10.4236/ns.2011.36060.