Listening to earthquakes

Here is a link to some very interesting work where seismic signals from earthquakes are processed to allow them to be audible. Although they are no longer at the correct frequency content, the human ear when listening to seismic "sounds" is capable of detecting patterns that cannot be discerned by the human eye when looking at wiggle traces on seismograms.

http://www.seismosoc.org/publications/SRL/SRL_83/srl_83-2_es/