Abstract: In this paper, we use S-transform method to calculate time-frequency spectrum of deformation and gravity data on weak seismicity region (Henan and surrounding areas). Comparing and analyzing disturbance events, seismic response, possible tectonic movement information, as well as, the instantaneous frequency characteristic parameters of Earth tide, the result shows that disturbing components of gravity mainly concentrate on 0.3~0.5 Hz, 0.001~0.1 Hz, and part of vibration has a strip distribution. Tectonic information may be contained in 0.1~0.18 Hz, and the energy changes in 0.1~0.18 Hz and instantaneous frequency characteristic parameters of Earth tide can be used to demonstrate the change of stress field, especially, for the far-field deformation and gravity changes, they have good precursory significance.

Key words: Gravity, Deformation, S-transform, Weak seismicity region