I'm sure Roger has more to say, but I would not use the 7 day list: quake information is being constantly revised, and some quakes are removed altogether (mine blasts, automated systems locating non-existant quakes from the seismic waves of other quakes). Also, using the 7 day list, 1/7 of the quakes are in the last 24 hours.

It would be probably easier to just use a later list (Roger would know where to find it) and there are other catalogues than USGS. Also, the USGS list has all quakes >2.5 in USA, but only >4.5 in other parts of the world unless "significant" (unusual). Only aftershocks >=4.5 are listed.
Chris