Roger,
I did some analysis several years ago which I sent Berkland which showed very
little evidence of tidal triggering in several areas of California which he was suggesting
higher confidence than I would have thought likely. After that, they started the web
site. I was in contact with him about a year ago when there was some concern regarding
a prediction for So. California and staff at SCSN was trying to pin down the origin of the
public concern (his web page).
To be quite honest, I have not followed his web page much because I have always
thought that while tidal triggering is likely in some circumstances, it is unlikely to
be very useful in actually predicting the time and location of real earthquakes. It is
more of a statistical/theoretical thing than something that can be applied in the
real world.
The only paper I ever wrote regarding tidal triggering was Chapter 7 of my PhD
thesis. I did find some evidence from global catalogs of some sort of energy
enhancement at certain times of the lunar cycle. But
I doubt that Berkland has a copy of this. It was copyrighted and published in
1999, but has had very limited distribution.
If you can tell me the papers he is citing, perhaps I could remember writing
them.
Anyway, having not followed his predictions much over the past several years,
I really don't have much of an opinion on them at this stage. Perhaps it is time
for me to do some homework on the matter and get back to you.