Figure 2.

Seismic traces illustrating the passage of trains along the Coachella Valley. Gray signals are filtered signals (1–10 Hz) from seismic stations along the railways (Figure 2), and the yellow signal is the stacked trace for the Piñon Flat array. The blue lines are offset using a velocity of 25 m/s (90 km/hr, 56 M/hr). The numbers on the right show the distance between the stations and the railway. The y axis label corresponds to distances of projected seismic station and Piñon Flat array coordinates along the railway.