Seismic activity by period, before the M6.4 event near Kozushima

From 26 June to 1 July, 2000. There was station correction.
The scale of the earthquakes increased with the shift of the hypocenters to the west and northwest. It appears that the hypocenters are occurring within a number of blocks, and that their movements are generally not contiguous. Epicenters appear in the periods determined by the activity in each block.

Japan Meteorological Agency

Seismic Activity in Japan June 2000