681787.fig.003a
(a)
681787.fig.003b
(b)
Figure 3: Time-frequency analysis of the bell accelerometer outputs from (a) Figure 2(a) and (b) Figure 2(c). The original time record is reproduced at the left of each plot. Amplitude is plotted using logarithmically spaced contours, with a total dynamic range of 40 dB down from the highest value.