Precursor Wave Signals Recorded by Gravimeter before Guangxi Jingxi M_S5.2 Earthquake

The observation data of the gPhone gravimeters at the Lingshan and Pingxiang seismic stations within 300 km from the epicenter of the Jingxi M_S5.2 earthquake are collected at a sampling rate of 1Hz. After zero drift correction and air pressure correction, the Butterworth high-pass filter is used to filter it. The solid tide signal in the signal, the wavelet power spectrum of the non-tidal gravity observation data before and after the earthquake is analyzed by wavelet analysis. It is found that low frequency signals with a period of 8~512 s appear in the gravity signal about 200 s before the earthquake, and the lower frequency signals in this frequency band appear early in time, then higher frequency signals appear in sequence; after the earthquake occurs, the signals in this frequency band begin to attenuate slightly, the higher frequency signals attenuate first, and then the lower frequency signals sequentially attenuate and disappear; through wavelet coherent analysis with seismic observation data, it is found that gravity the seismic precursor waves recorded by the instrument have good consistency within the frequency bandwidth of the seismograph.