Record sections for (a) shots from seismic line 5 recorded at station 50; and (b) shots from seismic line 6 recorded at station 17 (Fig. 2). In both sections, data have been bandpass filtered between 4 and 10 Hz and reduced at 6.5 km s⁻¹. Every third trace is plotted in both sections. Triangles mark locations of first arrivals.