Roger-no, not quite-sorry, my wording was misleading. I think it better to take quake #1 on Jan 1, count the quakes per day for the next 30 days (more than 500 km and less than 5000 km, for example, away)

Then do quake #2, which may also be on Jan 1....same thing. So, yes, you are right, many quakes would be counted more than once-probably would be counted several times.

You would not do a graph for each quake-which would be 40,000 graphs or whatever if you did all M5s....You would just add all the quakes together for each 1 day or 12 hour interval

number of quakes between 500 and 500 km from preceding M5 or M6 quake...
day 1: some big number
day 2: some other big number
.
.
Day 30: some big number...
Chris