Fig. 2

Seismic interferometry with a moving-frequency window. a Seismic signals recorded by the station FKSH01 at 2012/12/15 in the direction of north–south. b The seismic signals in the frequency domain, and application method of the moving frequency window. c Deconvolved waveforms of different bandpass-filtered seismic signals. The black dots indicate the travel time of the shear wave traveling from the borehole to the surface, and the arrow denotes the travel time from the well-log profile. d Deconvolved waveforms of different moving bandpass-filtered seismic signals. The black lines indicate the travel time of the shear wave at different frequencies