Statistical test of the relationship between sunspot number and the occurrence of the M_S≥7.0 earthquakes occurring in mainland China

For magnitude M_S≥7.0 earthquakes that occurred in mainland China from 1900 to 2017, we investigated the correlation between the 11-year-cycle variation of sunspot number and the occurrence of these earthquakes via the phase angle with a statistical test. The obtained results show that approximately 66 percent of them often occur within the period from two years before the valley point to three years after. This result is significant at the significance level （α=0.001）. At the end of 2019, the sunspot number dropped to the valley point. Therefore, earthquakes of M_S7.0 could be more prone to occur in mainland China from 2018 to 2022.