概率密度函数在内蒙古VP型垂直摆倾斜仪地震频段噪声分析中的应用OA

VP vertical pendulums at the Hailar,Hohhot,and Bayannur seismic monitoring stations in the Nei Mongol Zizhiqu show high operational quality.Raw second sampling observational data of the NS and EW components from the 3 stations during 2019-2023 are selected.The seismic noise magnitude(SNM)in the seismic frequency band(200-600 s)for the NS and EW components over five consecutive years is compared and analyzed using the probability density function and the traditional power spectral density method,respectively.The results show that the SNM values calculated by the two methods are close,with a root-mean-square error(RMSE)of 0.13,and their annual variation trends are consistent.This indicates that the probability density function method can be applied to evaluating the seismic noise magnitude of VP vertical pendulums.When calculating background noise,the data selection ranges used by the two algorithms differ.Among them,traditional calculation methods require manual screening of 12 days of observation data,which must be continuous,relatively calm,free of earthquake events,and minimally affected by external environmental interference,while probability density function analysis methods can use annual observation data.Furthermore,the probability density function analysis method is faster and more comprehensive in analyzing seismic noise levels.