Puerto Rico Earthquakes 2019 - 2020

In statistics
there are several algorithms known generally as cluster analysis that
group items by a measure. I imposed one artifical constraint
that the cluster boundaries should tile the plane - no gaps and no
overlaps. Even though we live on a sphere we are mostly acclimated to
use two-dimensional (flat) maps with more or less Cartesian
coordinates, so the cluster boundaries were coerced into being
rectangles that used longitude and latitude. Note that the rectangles
did not have to be congruent. I ignored depth when calculating the
distance between two points as I distrust the depth data even more
than usual. The idea was to calculate the clusters based on data from
the period 1910 to 2019 and hope that 2020 was similar.