While I'm trying to get my thoughts together about abstracts, thought I chime in on this one.

The variety of earthquake clouds suggested by proponents as precursors of quakes is pretty inclusive. The time lags between the clouds and quakes is also often a matter of "several days." In this case, especially in climates where the weather changes often, it is almost inevitable that you can find a cloud to suit your purpose.

Nobody that I have every heard/read has come up with a plausible link between quakes and clouds (except, of course, that they are generated by the planet, etc) I will not scorn these things out of hand, but some solid cause/effect relationship must be demonstrated. OR, a really high correlation between a cloud and a quake has to be shown and therefore encourage further investigation.

Most of the cloud pics that I have seen have been pretty normal vapor trails (and in California, the NS corridor is very close to the San Andreas, etc.) or other common atmospheric phenomena.

It is dimly possible that some sort of water vapor may be emitted from the soil due to pressure changes before a quake. But I think it unlikely that this would result in a distinctive high cloud pattern.

AND...of course, I may be totally wrong. I have lived long enough to see many scientific theories proven so. I would dearly love to see some good, reliable earthquake predictors discovered!

Cheers, PenyB