Hi all;

In order to see if this effect was only for great quakes I searched for 7+ quakes and examined them as listed below. The mag 7 quakes behave the same way so the effect is persistent, whatever the cause may be.

Combined NEIC and ANSS mag 7+ quakes from 1872 to 2007
1028 quakes total      1028 quakes total
 573 syzygy hits        573 syzygy hits
  38 perigee hits       perigee shift excluded
 611 total hits         573 total hits
probability 0.542      probability 0.542
significance 0.0004    significance 0.1685

As above with only mag 7
834 quakes total       834 quakes total
458 syzygy hits        458 syzygy hits
 32 perigee hits       perigee shift excluded
490 total hits         458 total hits
probability 0.542      probability 0.542
significance 0.0047    significance 0.3520

As above with only mag 8+
197 quakes total       197 quakes total
118 syzygy hits        118 syzygy hits
  6 perigee hits       perigee shift excluded
124 total hits         118 total hits
probability 0.542      probability 0.542
significance 0.0084    significance 0.0630

Roger