Just read and/skimmed an article in the May 15 EOS (Trans. American Geophysical Union) v. 88 no 20
It claims that anomalies in the ionosphere occur before major earthquakes, and that this is related to Radon release. It is by Sergei Pulinets of National Autonomous University of Mexico, in case anyone wants to try and find it via search (I did not find a link to the article, I think at AGU you have to login).
I found the article unconvincing. For example, how did the radon 100s of km away from the epicenter know that an earthquake would be set off and it should start leaking out of the ground. There is a statement withour reference that radon released underwater would get into the atmosphere...not so sure about that on the days to weeks time scale.
So, John V.....comments? Anyone? There may have been posts on related stuff here in the past...
Chris