Fig. 4From: River discharge prediction for ungauged mountainous river basins during heavy rain events based on seismic noise dataSpectrograms of seismic noise recorded at the N.FGTH station for the event of September 2015. a Running spectra of the raw seismogram. b Spectra at the three time periods shown in (a), where black, blue, and red spectrum are obtained in the daytime, midnight, and peak streamflow periods, respectively. c Running spectra of the seismogram after “clipping” transient peaks (e.g., earthquakes). d Spectra at the three time periods shown in (c). The gray dashed lines in each panel represent the spectral window used for our analysis (1–2 Hz)Back to article page