Hi,

I was cleaning out my e-mail boxes today and came across this e-mail I received in 2001 from a scientist in Greece responding to my question about earthquake faults as the source for ear tone. Petra

"As far as it concerns your question, the following could be a possible explanation of the "sounds" generated before many EQs.

Since the rock failure (that produces finally an Eq, is a progressive process from microfracturing to macrofracturing, that occurs in the stress loaded focal area, plus the fact that the lithosphere consists at almost 45% from quartzite) generates mostly piezoelectric electrical signals at almost a continuous spectrum, the part of this energy that is at the audible range, could induce (secondarily) mechanical oscillations (in a wide range of audible and not frequencies) of quartzite crystal of the focal area in the lithosphere.
Therefore the fact that such sounds are being detected many times prior to EQs does not surprise me. Animals have the ability to listen beyond the human audible range i.e a sound of 20Kc/s is quite easily detected by dogs but not from human beings."