Three pieces of information which I believe could be used to help us determine how and why "ear tones" are being generated are the following:

1. They are often heard in one ear or the other, but not both at the same time. I am guessing that that means that the signals are polarized in some manner.

2. They may be heard in one ear, and then in the other ear at some multiple of a little over 6 hours time later. That suggests to me that the same fault zone may be producing both of those signals. And that could mean that the polarity of the signals changes when the Earth rotates about 90 degrees relative to the sun and the moon.

3. Some laboratory devices known as "cell disrupters" generate a type of signal, probably electromagnetic, which sounds just like a high frequency "ear tone." However, the sound is heard in both ears at the same time rather than one ear or the other. I believe that it can normally be heard by only people who are earthquake sensitive.

Those data are my personal observations. They should not be regarded as established fact until they are checked by some research group.