Figure 2
From: Anatomy of a microearthquake sequence on an active normal fault

Vertical-component velocity records of the seismic sequence at the (a) COL3, (b) SNR3 and (c) VDS3 stations.
The waveforms are band-pass-filtered from 1 to 20 Hz and are amplitude-normalised. Events are ordered in time from earliest to latest and the event number increases with the event origin time. Waveforms are aligned with respect to the first P-wave arrival time. Red and green vertical bars indicate windows containing the P- and S-wave arrival times, respectively. The S-to-P (SP) conversion at shallow interfaces is also indicated.