The "proof" relates, as has been mentioned already, to the cascading dynamics of the rupture process. From this it can be argued that any precursor for a magnitude 8 would have to be a precursor for the magnitude 2 that initiates it, which would mean there would have to be the same precursor for every magnitude 2. My belief is that this argument is flawed. A precursor could still relate to the state of the local crustal volume that permits a magnitude 2 to escalate into an 8. In other words, the precursor is not a function of the succeeding earthquake but of crustal processes that precede the quake.

I was chatting to Prof Uyeda the other week who has a much more upbeat view of earthquake prediction. He believes that scientific prediction will be possible by 2010 and reliable by 2020. He is fond of pointing out that in the 1890s Lord Kelvin stated that a heavier than air flying machine would never be possible, and that Orville Wright stated it would not be possible within 50 years (this said two years before he was in one!).

The problem, of course, is that what goes on in Japan is hard to keep up with as it all gets published in Japanese.