Characteristics of Ambient Seismic Noise from Broadband Seismic Array in Western Hubei Region

Based on the three-component ambient noise data recorded by broadband seismic stations during different time in Western Hubei, the noise cross-correlation functions between stations are calculated and stacked. The slowness spectra of Rayleigh wave and Love wave are obtained by beamforming analysis method to study the temporal and spatial distribution of ambient noise sources in Western Hubei. The results show that in the 5~10 s period of the second microseismic zone, the ambient noise originates from the South Pacific Ocean and has no seasonal variation. In the 10~20 s period of the first microseismic zone, the slowness spectra shows obvious energy loop distribution, indicating that the sources of ambient noise distribute in many directions. In the longer period range of 20~40 s, there are also obvious energy loops in the slowness spectra, and the generation mechanism is likely to be similar to the mechanism of infragravity waves proposed for longer periods. In different periods, the ambient noise sources have different distributions, but there are obvious energy loops in the period of 10~40 s, which indicates that there are noise sources distributed in all directions. Therefore, the calculation of cross-correlations in the period of 10~40 s by using continuous ambient noise records in different time satisfies the theoretical premise of ambient noise surface wave tomography.