[Roger Hunter]

Author David Nabhan has written a book stating that quakes are most likely to happen within 3 hours of dawn or dusk and are also more likely within 36 hours of new or full moons.

I looked at all the 7+ quakes in the NEIC catalog from 1973 to 2013.

There were 638 of them.

124 were within 36 hours of a new or full moon.

279 were within 3 hours of 6:00 AM or PM.

Impressed?

Well, new/full moons happen every 2 weeks. 36 hours is 1.5 days or 3 days in all (+/-) so those windows are 52*6 days which is 312/365 so the odds on a hit are 0.855. Pretty hard to miss. He should have 545 hits, not 124.

3 hours +/- is 6 hours twice a day which is half a day so the odds on a hit are 0.50 so half the quakes should be hits.

He had 279 hits and should have had 319 so that's false too.

Now he was writing about the west coast so I looked at only quakes within the -115 to -130 longitude range. There 60% of the mag 7+ quakes were within +/- 3 hours of dawn or dusk.

The problem is that there were only 10 of them so while 6/10 is statistically significant it's too small a sample to be considered reliable.

Roger