Figures of the Article

• Distribution of permanent broad-band stations in Chinese mainland
• Probability density function constructed by using 34 626 PSDs of vertical components recorded at the station GS.GTA
• Self-noise curves of some common seismometers
• Diurnal variations of PDF median values for the station GS.GTA constructed using 34 626 PSDs
• Seasonal variations of noise level for the stations GS.GTA （a） and FJ.NDZW （b） in 2014
• Distribution of noise median value for the period bands 0.1−1 s （a）， 2−10 s （b），10−20 s （c） and 20−50 s （d）
• Distribution of noise median value for the secondary microseism in short period 2−6 s （a） and long period 6−10 s （b）
• PDFs for different networks of Chinese mainland
• Noise baselines for different networks
• Examples of abnormal PSDs and their time series for the Anhui network