The Characteristics of Time Residual between M_L≥2.0 Earthquake Occurrence and Its Corresponding Time of Solid Earth Tidal Maximum in Tangshan Old Seismic Region

Based on the time residual between earthquake occurrence and its corresponding time of solid earth tidal maximum, we analyzed the distribution of these time residuals in different statistics time span with the month, half month, day and half day for Tangshan M_L ≥ 2.0 earthquakes. The results reflect that the higher seismicity time in Tangshan is more or less synchronous with the earth tidal maximum, which maybe indicate these earthquakes had been triggered by tide to some extent. In space, those earthquakes with more chances to fall into the tidal triggering time mostly locate in the middle and eastern of Tangshan fault. This phenomenon maybe also indicates the remarkable area for the regional stress accumulating is still concentrated at this segment mentioned above. In addition, in 1-3 weeks after the main strong earthquake, the aftershocks are distinctly enhanced by earth tide. Thus it needs to put more attention on the occurrence of strong aftershock when the time is close to the tidal maximum.