Appended figure2-1 Recent seismic activity, including small earthquakes I (M 2 or greater, July 1976 - June 1995).
(Note) In the northern and eastern parts of Hokkaido, networks of stations were successively arranged beginning in the late 1980s. Subsequently, the precision of hypocenter determinations has improved. Earthquake-detection ability is low at Kunashiri Island and eastward.
[Prepared from data of Hokkaido University]
Shallow earthquakes with a hypocenter of 30 km or less in depth.
Deeper earthquakes with a hypocenter of over 30 km in depth.
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