This will either debunk itself in a week, or we move this prediction to another forum. http://www.space.com/scienceastronomy/quake_prediction_030915.html Edit: A summary of this thread: A quake with a magnitude >= 7.0 was predicted for Tokyo for Tuesday or Wednesday. In fact, Tokyo experienced a magnitude 5.5 quake on Saturday. The energy was about 99.5% less than expected. The Richter value was in error by 21% I would think that the odds of a 5.5 quake on any day is no worse than 1:3500. So, if we were off by three days, we might allow for odds like 1:1000 of getting this close by chance. Of course this is just for perspective and not meant as hard numbers. The real number may well be more like 1:100. I didn’t find a good number for the frequency of Japanese quakes, but I did find a couple of interesting, related sites. http://neic.usgs.gov/neis/current/japan.html http://www.owlnet.rice.edu/~geol108/eq4/site_directory.htm#Earthquakes It is not clear, but the key measure apparently [according to this news report] is measured in reference to the Richter Scale value and not in terms of energy. It seems that an arugment might be made that with no better than 1:100 chance of random success, this quake was predicted within 21% of the actual magnitude. It is also possible that the result [if we use energy as the indicator] was in fact only 0.5% of the expected value. Edit #2: Then, a week later... TOKYO, Sept. 26 — Three powerful earthquakes, one of them of potentially historic magnitude [estimated as being an 8.0], struck Hokkaido in northern Japan early Friday morning, causing major structural damage, NBC News reported. The quakes injured more than 240 people and generated a 7-foot-high tsunami off the coast of Hokkaido. Tsunami advisories were issued for much of the Pacific region, including Japan, Russia and the Philippines. http://www.msnbc.com/news/971921.asp?pne=msntv This event appears to yield odds of random success - of predicting any quake >=7.0, anywhere in Japan within one week - of around 1:600.