Hi all;

I can't resist numbers like those quoted so I took a look.
I used all 7+ quakes in the Centennial Catalog from 1900-2001 and compared them to New moon/perigee windows, defined as the 4 day period around the new moon if perigee was inside.

Results were:

There were 1263 New moons during this period.

There were 368 windows in 37254 days.
The windows covered 1472 days.
This is 3.95 percent of the time.

There were 36 quakes in windows.
There were 796 quakes.
This is 4.52 percent of the quakes.

There were 368 windows.
There were 36 windows with quakes.
This is 9.78 of the windows.

A far cry from the figures in the referenced article.

Roger