Seismic Characterization of Tunnel Boring Machine Activity


Spectrograms

Spectrograms (spectra versus time) for the vertical component of an L-4C (1hz) sensor located in the tunnel at site TNL. Each spectrogram is a half hour long.

Sequential spectrograms for 3 hours and 45 minutes of continuous seismic data are presented here by groups of two. Time increases from left to right in each spectrogram, and each successive group from top to bottom follows the one preceeding it.


Introduction | Spectrograms | Signal and Noise Spectra | TBM Signal Attentuation
Frequency-Wavenumber Analysis of the Mini-Array | Acoustic Resonances | Conclusions