Hokkaido Region

a) An M6.8 earthquake occurred on 28 January offshore of eastern Hokkaido [Southeast Offshore of Nemuro Peninsula] (maximum intensity: 4). The current activity is occurring on the southwest margin of the aftershock area of the 1994 [Earthquake East Offshore of Hokkaido].
b) There was a deep-focus M5.0 earthquake on 6 January in the south of the Sea of Ohkotsk.

Note:
M=magnitude
N: total number of events in the figure
depth=depth of hypocenter
UND=Earthquakes of less than M1.0 and earthquakes whose magnitude was not recorded.
The key to the symbols shows on the left the size of an earthquake and on the right the depth of the hypocenter.

Japan Meteorological Agency,Science and Technology Agency

Seismic Activity in Japan January 2000