... since no one commented on my earlier thoughts about this.

I have my own ear tone theory as relates to earthquakes. I believe what we are hearing are overtones of the ULF sounds emitted by the fracturing of rock before the actual event. Obviously, humans are not capable of hearing ULF sounds. Not directly. But if these events produced ULF sounds that in themselves, generated overtones, we might certainly hear them.

Comments anyone?

Cathryn