Aftershock Activity of the Off-shore Tokachi Earthquake

The aftershock activity of the 2003 Off-shore Tokachi earthquake on September 26, 2003 (M8.0) has been declining normally. There were no aftershocks equal to or larger than M5.0 during January 2004. The largest aftershocks were two M4.9 events on January 2 (maximum seismic intensity 2) and on January 17 (maximum seismic intensity 1). There were no aftershocks with intensity equal to or over seismic intensity 4. The M4.6 event on January 13, and the M4.7 on January 19 both had a maximum seismic intensity 3.