Chris,

Truly, what needs to happen is to connect with a group of people who understand all kinds of sound and let them try to figure out what it is because it crosses to many disciplines of science, including medicine.

It could easily be something that is processed by the brain and somehow in the process the brain sends a signal to the ear. I do think it is friction on faults that causes it. The reason I say that is because from the experiences of most ear tone recipients every fault has its own unique sound and if its a long fault like the SAF, certain areas of the fault produce individual sounds. For me as an example, Central Parkfield does not sound like Cholame.

So until we find some experts who understand all types of sound, I don't think we are going to get very far. But if this one single thing could be understood and converted to an instrument, it would be so much better than a human being with all of our frailties.

I hope by the time you read this you will have accomplished your work with good results.

Petra