关键词: 变分模态分解, 地震信号, 能量熵, 自适应阈值, 去噪

Abstract: Seismic signal is a kind of non-stationary signal，which is composed of seismic subwaves with different amplitude and frequency at different propagation times． According to the time-frequency characteristics of seismic signals，a denoising method based on the relevant energy entropy threshold of variational modal decomposition is proposed． The variational modal decomposition algorithm is used to decompose seismic signals into modal components from high frequency to low frequency and a certain bandwidth． The normalized correlation coefficient between the modal components and the seismic signal is calculated． And the effective information and noise in the modal components are located． Each modal component is divided into several sub-ranges，and the noise energy entropy of each sub-interval is calculated separately． The modal component coefficient of the maximum range of energy entropy is selected as the noise variance of the component to obtain the threshold of the component． The synthetic seismic model and the actual seismic signal are de-noised and compared with the variational modal decomposition and de-noising method that directly removes high-frequency components． The results show that this method can effectively extract the active components of seismic signals and improve the signal-to-noise ratio．

Key words: variational mode decomposition( VMD) , seismic, energy entropy, adaptive threshold, denoising