Historical Richter
8.0 or greater
earthquakes. When
the 11 events east
of Hokkaido split
into two clusters
we obtain five
clusters with three
prominent outliers
- the red dot
(06/11/1902 8.0) ;
the orange dot
south of
Kamchatka
(05/01/1915 8.3
paired with an
earlier 7.7) and the
yellow dot on
western Honshu
(02/07/1897 8.3)