Abstract: The focal mechanism solution and focal depth of the Changning M_S6.0 earthquake sequence in Sichuan on June 17, 2019 were solved using the near-earthquake waveform inversion method, and a total of 30 reliable focal mechanism solutions and focal depths of the earthquakes with M>3.0 were obtained. Combining with the existing focal mechanism solutions in the area, we carry out the inversion of the tectonic stress field in the focal area, and explore the tectonic stress environment in the focal area on a small scale. The inversion results show that the area near the epicenter is dominated by thrust-type stress, and some areas include a small amount of strike-slip components and mixed types. The direction of the maximum principal compressive stress is mainly in the direction of NEE or NE. In the area to the east of Junlian, unlike the thrust type in the north, the stress properties are mainly strike-slip type with a small amount of mixed type, and the maximum principal compressive stress direction is close to the EW direction. There is a certain angle between the direction of the tectonic stress field and the tectonic stress forming the Changning anticline. The 2019 Changning M_S6.0 earthquake may be caused by the reverse fault activity at the core of the anticline above the detachment surface of the area caused by the NE or NEE approaching horizontal stress compression.

Key words: 2019 Changning M_S6.0 earthquake, Focal mechanism solution, Tectonic stress field