To investigate for the possible couplig path, we looked for the coherence of the peaks excited in hrec during the acoustic injection in the hall and several accelerometers within the hall: those on vacuum chambers, TCS benches, and so on.

The first Table concerns the acoustic injection time and it reports in red  shades, for each peak's frequency, the maximum coherence in a +-1.5 Hz window across the peak. The second table, lists the SNR at each peak's frequency, computed as the ratio of the RMS between injection time and quiet time, each RMS is computed over a +-1.5 Hz frequency window across the peak frequency.

The indication is not strong, but some larger coherence is noted for three channels: accelerometers at SDB1 (DT), NI and WI chambers. 

The SNR is a bit larger at SDB1 (DT) and NI which are closer to the loudspeaker (DET terrace). Although not for SR.

Table 3 is the coherence again but computed during a quiet time.   There is no relevant coherence during quiet time.

Figures, one for each peak, illustrate superposed coherences at injection time.