Analysis on the difference of high-frequency seismic ambient noise in cities
Selecting continuous waveforms of vertical component from SSE,BJT,and ENS seismic stations from January 1st to 28th,2023,we analyzed the differences in human-induced noise in different cities.The results show that in the study period the seismic ambient noise level of SSE and BJT is lower on Friday and the level of ENS is lower on Wednesday;in the frequency range of 4-14 Hz,the seismic ambient noise level of different regions significantly decreased during the Spring Festival,with the root-mean-square displacement of SSE seismic station decreasing by about 0.4 nm,the root-mean-square displacement of BJT seismic station decreasing by about 0.2 nm,and the root-mean-square displacement of ENS seismic station decreasing by about 3.5 nm;in the frequency range of 0.1-0.2 Hz,the significant change in normalized displacement caused by distant earthquake events can be observed,and the duration of displacement change can intuitively reflect the duration of the earthquake,thereby reflecting the differences in the magnitude of the earthquakes.For the influence of human activities on the seismic ambient noise of the stations,the analysis shows that:among the three stations,BJT seismic station has the least high-frequency seismic ambient noise interference;at f=2 Hz,the seismic ambient noise level of SSE seismic station is higher;at mechanical frequency f ≥ 5 Hz,the seismic ambient noise level of ENS seismic station is higher.
seismic ambient noisenoise power spectral densityroot mean square displacementnormalized displacement
万方数据
维普
