Is the Apparent Correlation between Solar-Geomagnetic Activity and Occurrence of Powerful Earthquakes a Casual Artifact?

Abstract

So far, many efforts have been made to provide a reliable and robust mechanism for the occurrence of large earthquakes. In recent years, different studies have been conducted on the possible correlation between solar-terrestrial interactions and the occurrence of earthquakes. In this paper, the hypothesis that there is a correlation between solar-geomagnetic activities and powerful earthquakes first is investigated in three case studies, and then it is discussed by studying the variations of indices, including F10.7, Kp, ap, and Dst, before 333 large earthquakes (Mw ≥ 7.0) that occurred between 1 January 2000 and 28 April 2022. As the time series of the solar index follows special cycles, in another scenario, after removing the non-linear variations with fitting a polynomial, the anomalous F10.7 variations above and below the median ± 1.25 × interquartile ranges were considered. Although anomalies in solar and magnetic indices are observed in 33% of earthquakes one day before the occurrence, by analyzing 100 simulated data sets, we find that analogous anomalies can be found. Therefore, it can be concluded that there is no significant correlation between solar and geomagnetic indices and the occurrence of strong earthquakes. These findings could be effective in better defining alternative robust mechanisms for the occurrence of earthquakes that are more of internal origin than external to the Earth system.

Keywords

• earthquake
• solar-geomagnetic activity
• anomalous variation
• time series analysis