To get any meaningful results, we'll need a decent sample size. Magnitude 7.0+ quakes in Japan are a fairly rare phenomenon, occurring 1-2 times per year. If we pull out a somewhat larger data set of 136 such quakes in the last 100 years (https://www.volcanodiscovery.com/earthquakes/japan/largest.h...), we'll notice that the quakes are fairly evenly distributed between the months.
The mean is (of course) 8.33%, and the standard deviation 1.91%. All months fall within 2 standard deviations from the mean (March is highest at 11.62%, followed by Feb at 11.06%, Jun 10.51% and Nov 9.76%). So, nothing particularly interesting to see here. Also, if we do the same "three-month window" analysis you did, the winner is February (with 30.68%, somewhat higher than the expected 25%).
Wow, I just checked out that website and I can't believe you did that analysis! That's pretty awesome. You somehow got the data out of that site, and analyzed it.
But I did a quick sanity check on your numbers (searching on that site quakes from March 18 1922 to March 18 2022) and there are actually 153 quakes 7+ (not 136). If you share the raw data it will be more convincing!
Unless you do I'm going to take my 10 year sample from 2011 with a 68.75% of chance of quake in March (+- 1 month) as gospel :)
So pretty hard to predict and essentially random, meaning predicting when a given quake will occur should be, extremely challenging, essentially predicting a random variable, which would be pretty incredibly amazing. Good to see.
The mean is (of course) 8.33%, and the standard deviation 1.91%. All months fall within 2 standard deviations from the mean (March is highest at 11.62%, followed by Feb at 11.06%, Jun 10.51% and Nov 9.76%). So, nothing particularly interesting to see here. Also, if we do the same "three-month window" analysis you did, the winner is February (with 30.68%, somewhat higher than the expected 25%).