CanMan, I've heard, and been thoroughly scared by, sonic booms. The sounds that are being heard are not sonic booms, at least to my understanding.
DUMBs are definitely something being spoken about, and there are strange anomolies that are going on.
I will say that some of the larger eqs we have had in the last 5-8 years have changed the axis of the earth, but I don't know if that's part of this? The sounds appear far too mechanical in many ways for that to be the cause. In some cases, I think there's fraud, too. And some other cases, I think it's very likely that a strange echo effect from construction, or from passing vehicles (like trains, or big trucks) may be the answer.
But some of those sounds...well...I just don't know.
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Herding Cats