AbstractResponse characteristics of key strata during the periodic weighting process in Dongjiahe coal mine were investigated using micro-seismic (MS) monitoring. Fracture types of key strata were identified through the moment tensor inversion. Finally, fracture mechanism of roof key strata was revealed from a microscopic viewpoint. The results show that there are three concentrations of MS events distributed along the dip direction. And two MS event clusters were formed in “pairs” before and behind the working face. Along the strike direction, tensile and shear factures occur in front of the working face with a dip angle of 54°, while the micro-fractures are mainly mixed and partial shear types behind the working face. By contrast, the rock fracture usually occurs behind the working face along the dip direction. The micro-fractures are mainly tensile and mixed types before fracturing compared to mainly mixed and shear fractures with slight tensile ones after fracturing. The fracture pattern basically conforms to the “O-X” type. The X-shaped fracture extends outward with an angle of 46° with the due north. The findings in this paper provide a theoretical reference for strata behaviours and hazard risk assessment under similar conditions.