Hi Roger,

Coupla things. There were 30 quakes on cross days, whereas one would expect, if there were no correlation between "cross days" and quakes, 24 quakes (1.4% X 1709 quakes). Admittedly 30 is quite a bit larger than 24, but does that excess of just six quakes really represent odds of <.000001? It seems results like this could easily be due to small sample size.

Also, your finding of only 1709 quakes >M7 in a 107-year period is surprising. My figures suggest a long-term average of 22/year, for a total of some 2350. Apparently many quakes were missed early in the period due to lack of instrumentation. Is there any tendency for your cross days to have occurred more toward the latter part of the period in question? Because, if so, that would easily be sufficient to account for the non-random results.

Mike W.