Hi 2 Cents,

Only a very small percentage of ear tones find there are no immediate matches to quakes. While these are no good for use in short term prediction, I never consider them expired. The reason I don't is because ear tones indicate there is some kind of movement within a fault. One may have to have several of those events before the fault breaks, so it doesn't invalidate the ear tone, it just loses its use in short term prediction.

I get a lot of small ear tones for the SF Bay area which I no longer try to match because they are so small that if we have more than one within a few days its impossible to say which tone matched each quake.

Several months ago I heard a truly ominous ear tone and I believe I know the location from where it came from, but to date there is no match. But I'm not the only person to hear this sound. Cathryn has heard it twice. I believe when this fault breaks its going to deliver something around an 8 magnitude quake. But it isn't ready yet.

If you recall the analogy about asperities inside faults being like teeth on a comb, and as each asperity (tooth) breaks away, the fault becomes less stable. At some point, the asperities that held it together are gone and then stress causes the fault to break. Ear tones are more than likely the sounds the asperities (rocks) make as they are broken away. If its the last one on the fault, then you get a quake immediately, if its not, then you have to wait until more asperities break away.

This is why a lot more research is needed.

Petra