Abstract：We study the moon phase modulation effect of small earthquakes above M1 in Shandong inland area since 2008, combining with the variation of seismic b value in this area. The results show that there are anomalies of low b value and high modulation ratio in the area before the 2020-02-18 Changqing M4.1 earthquake, and we calculate the deflection phenomenon of P-axis of the composite nodal plane solution, which is very consistent with the variation period of low b value of small earthquakes. In addition, before the 6 earthquakes above M4 in this area, the abnormality of modulation ratio ≥0.33 occurs 4 times. In 2011 and 2016, the two Fanxian earthquakes did not show the above changes, which may be related to the activity mechanism of oil recovery in Fanxian small earthquake concentration area.
LIN Mei,ZHENG Jianchang. Analysis of Regional Small Earthquake Modulation Ratio Anomalies before Changqing M4.1 Earthquake[J]. jgg, 2021, 41(11): 1207-1210.
