Time–distance diagram for the seismic source 2, obtained from the filtered HMI dopplergram without (left) and with (right) theoretical curves. The TD diagram shows the ridge derived from ripples produced at some distance from the event location by acoustic waves in their first bounce from the photosphere (lower white line) and the second bounce (upper white line). The start (zero) time on the Y-axis is 11:29.04 UT, which corresponds to the shock deposition and seismic response initiation at 11:55:37 UT. The grey colour bars on the right show the background Doppler velocities in m/s.