Bands for the distances not covered cover a lot more territory.
A simple calculation shows that 32 degrees of territory are covered
by these bands - that is 32/180 th of the earth's surface (about 18%)
assuming random distribution of the bands with respect to the earth's
surface. A more complicated calculation using spherical geometry
measuration formulae shows that the area covered by these bands
is about 15% of the total surface of the earth (the band at the antipode
of 10 degrees is the outlier). The 15% area covered is approximately
what we have been seeing in the probabilities, so, the distribution of
earthquakes with respect to the mainshocks studied appears to be
approximately random.