Abstract:This paper applies the P-wave initial motion to invert the focal mechanisms of 293 earthquakes with ML ≥ 2.0 in the Changdao area, Shandong Province. According to focal mechanism solutions, the stress tensor of Changdao was retrieved to calculate the spatial-temporal evolution of the focal mechanism consistency parameter of each node. We then analyzed the stress condition in the study area and the spatial-temporal characteristics of the consistency parameters. Our results showed that (1) The type of earthquake source was strike-slip type > normal faulting type > thrust faulting type, and we judged that the seismogenic fault stretches along the SE and exhibits nearly vertical strike-slip movement, which mainly showed horizontal motion. (2) The inversion showed that the azimuth and plunge of the principal compressive stress axis were 101.4° and 29.1°, respectively; 280.8° and 60.8°, respectively, for the middle compressive stress axis; and 11.3° and 0.3°, respectively, for the tensile stress axis. The stress tensor variance was 0.085. (3) There was a certain correlation between the time-space distribution of focal mechanism consistency parameters and the seismicity of moderate-strong earthquakes. Before the occurrence of a moderate-strong earthquake, the focal mechanism consistency parameters were relatively low, and the tectonic stress field near the earthquake source zones increased. In general, the focal mechanism consistency parameters of the study area exhibited low values in central part and high values on both edges, and all ML ≥ 4.0 earthquakes occurred in areas with extremely low values and in the transitional areas from high values to low values.