Abstract: Debris flow is a common disaster in the mountains. It brings serious threat to the mountain transportation, hydraulic and hydro-power engineering and security of life and property of local residents. When debris flow happens, it is ferocious and of destructive power. Debris flow generates infrasound signals when it happens. This paper explains the characteristics of the infrasound signal which is generated by debris flow, and introduces the Hilbert Huang transform (HHT) time-frequency analysis method. Then HHT is compared with the other time-frequency analysis methods like the short-time Fourier transform (STFT) and the Wigner-Ville distribution (WVD). The simulation results show that the Hilbert Huang transform is more suitable for the analysis of infrasound signal generated by the debris flow than the other time-frequency analysis methods.

Key words: debris flow, infrasound, time-frequency analysis, HHT