PMEL Acoustics Program logo National Oceanic and Atmospheric Administration Pacific Marine Environmental Laboratory Acoustics Program

Cryogenic (Ice)

 


Click on spectrograms for full-sized image.

 

Calving: Spectrogram of an iceberg calving (large section of iceberg breaking off) while adrift. The calving signal is short duration, broad band from 1-440 Hz generated by ice cracking and crack propagation. Audio sped up 3X normal. 4.3MB wav file Iceberg calving spectrogram
Iceberg Harmonic Tremor: Generated by iceberg in contact with the seafloor or other iceberg. This spectrogram has a fundamental frequency of 40 Hz, with a 40 Hz overtone spacing. Multiple overtones are visible in the spectrogram. Audio sped up 3X normal. 271K wav file Iceberg harmonic tremor spectrogram
Original icequake (bloop) sound: The broad spectrum sounds recorded in the summer of 1997 are consistent with icequakes generated by large icebergs as they crack and fracture. NOAA hydrophones deployed in the Scotia Sea detected numerous icequakes with spectrograms very similar to “Bloop”. Recorded signal sped up 16 times. 162K wav file icequake (bloop) spectrogram
Iceberg Grounding on Seafloor (Slow Down): The sound slowly descends in frequency over about 7 minutes as the drifting iceberg slows to a stop once it comes in contact with the seafloor. Recorded signal sped up 16 times. 283K wav file bloop spectrogram