Whale geologists

The voice of the fin whale penetrates the earth’s crust beneath the sea floor – a whale born ultrasound. By pure coincidence, it seems to have the right amplitude and frequency to easily penetrate the rocks for hundreds of metres in depth, reflecting and refracting where the rock changes its density, or there is a a crustal interface – a change between one type of rock and another, between a rock and a sediment, or just a big crack and an air or liquid gap. At these points, abrupt changes in...