Tidal Triggering of the 2019 Jingxi M_S5.2 Earthquake Sequence

In this paper, the tidal triggering phenomenon of the 2019 Jingxi M_S5.2 earthquake sequence is studied. We calculated the tidal Coulomb failure stress of Jingxi earthquake and the largest aftershock with M_S4.3, discussed the earth tide modulation of Jingxi earthquake sequence, analyzed the dominant periodic components of tidal modulation by Shuster spectrum and KORRECT. Three conclusions are obtained. ① The tidal Coulomb failure stress on the surface of seismic fault of Jingxi earthquake is positive, which is significantly triggered by solid tide. ② The average daily earthquake occurrence rate of the two days before and after the new moon and the full moon is higher than the background level, the occurrence rate of the new moon is the highest, the earthquake sequence is more significant by the influence of semi-diurnal tide and diurnal tide, and it is also modulated by tidal stress to a certain extent. ③ The largest aftershock with M_S4.3 have occurred in the period of tidal modulation, but the tidal stress exerted a sliding resistance on its seismogenic fault. The activity of M_S4.3 earthquake may be mainly related to the enhancement of regional stress field and the adjustment of focal stress field after the occurrence of the main shock.