Hebei Yongqing M4.3 Earthquake on February 12, 2018

This paper gives a relatively reliable focal mechanism solution of the M4.3 earthquake in Yongqing, Hebei province on February 12, 2018 through the mutual corroboration of the result of P-wave first motion method and that of waveform inversion. And then, combining with seismic geological data, the result indicates that the Hexiwu fault may be the seismogenic structure. The analysis of seismic activity characteristics, the focal mechanism solutions and the apparent stress of the middle and south section of Hebei plain seismic belt before the yongqing earthquake shows that there is a dynamic process of stress field enhancement before the earthquake. Finally, combining with the deep and shallow structural features of the middle section of hebei plain seismic belt, the result shows that the region may has the tectonic background of strong earthquakes.