Fig. 3

Example of a receiver gather at receiver 9 with shot points starting in niche 8 with SP12 to SP31 (except SP23) in gallery 08 (Fig. 1A along gray dotted line). Red dots indicate traveltime picks for P-waves and blue dots for S-waves. Shown are the three components of the geophone. comp 1: vertical, comp 2: parallel and comp 3: perpendicular to the tunnel wall