Figure 8
From: Marine mammal acoustic detections in the Greenland and Barents Sea, 2013 – 2014 seasons
Spectrogram of 20 Hz fin whale signals coinciding with pulses from a seismic survey. (Hann window, spectral resolution 4096, timescale 2:00 min, logarithmic frequency scale 10–700 Hz). The spectrogram shows the 20 Hz double downsweep signals, repeated every ±14 s. Although less clear, there seems to be higher frequency energy around 127–131 Hz coinciding with the temporal pattern of the 20 Hz signals, occurring less than 0.5 s before the start of the latter, with a harmonic around 260 Hz.
