Possible connection between solar activity and local seismicity

Abstract

Recently, much attention has been paid to the relationship between solar and seismic activities toward earthquake (EQ) prediction. Some researchers believe in the existence of a connection between them; however, others completely refuse the existence of such a connection. In this study, the correlation between solar disturbances and occurrence of EQs during two consecutive solar cycles (SCs) 23 & 24 from 1996 to 2019 was investigated to explore such a relationship. The study was performed on both global and local scales. On a global scale, we studied the temporal variations of EQs number and the corresponding solar activity, represented by sunspot number. On the other hand, we selected several seismic zones characterized with high seismic activities and shallow depth EQs. For each zone we examined the day-to-day variations in the number of EQs and explored the space weather “chain of action” from the Sun to Earth in order to examine whether these events have an influence to increase the number of EQs or not. Results showed that, for the whole global seismicity, no clear correlation is found between EQs occurrence and solar activity, while for small active seismic zones, the connection between them is significant. An increase in the number of shallow EQs in the studied seismic zones is observed in association with the variations of examined space weather indices. Thus, the current study suggests a possible connection between solar activity and localized seismic activities. However, the solar-magnetosphere-lithosphere coupling and interaction during solar events need further study and investigation for a better understanding of their EQ triggering effects.