Whale song recorded by ocean-floor seismometers
Scientists led from University College London placed 50 seismometers on the Atlantic Ocean seafloor in the Azores-Madeira-Canary Islands region. Their aim was to record the signals from earthquakes which they could use to image the interior of the Earth. The technique is not dissimilar to that employed by medical doctors to build CAT scans of the human body. But in addition to sensing quakes, the instruments also picked up whale song. The data above has been "sonified" to make it audible. The large bump towards the end is an earthquake.