Seismic activity at border between Tochigi and Gumma Prefs.

In area b an M4.1 earthquake occurred on 6 February at a depth of 11km.Activity in this area has intensified from the beginning of January. Furthermore, in December there was activity, with a maximum 4.1 event, on the southeast verge of this area.

Japan Meteorological Agency

Seismic Activity in Japan January 2000