Analyzing IMOS hydrophone recordings

Many thanks to researchers at Curtin University for providing a full day of recordings from the three active IMOS hydrophones.

They each recorded for five minutes out of every fifteen. The two Rottnest recorders are staggered so there is a better chance of detecting events. One of the Rottnest hydrophones is nearly in sync with the Scott Reef recorder, allowing triangulation on events along the 7th arc about 20% over time. There are about 300 five minute recordings to be analyzed.

The dataset has been converted to .flac audio files, and some 200 spectrograms have been generated for detecting triangulation events. Novel signal extraction techniques are being tried, combining visual coincidence plots and audible methods.

The whale songs are subsonic, but its fascinating to hear them chorusing over long distances when sped up.

A written proposal has been mailed to the CTBTO on their invitation for contractual access to their hydrophone and infrasound archives. Those have 100% coverage of the time frame, with triangulation potential from multiple sites.

The validation and encouragement received from several scientific researchers to pursue this search approach is greatly appreciated!