Kanto-Chubu Region

a) Intensified seismic activity, including an M4.1 earthquake on 16 December, occurred on the border of Tochigi and Gumma Prefs. [Northern Tochigi Prefecture] (maximum intensity: 4).
b) An M4.0 earthquake occurred on 27 December in southwestern Ibaraki Pref. [Southern Ibaraki Prefecture] (maximum intensity: 3).
c) An M4.8 earthquake occurred on 4 December on the lower plane of double-planed deep-focus seismic zone off the southern coast of Ibaraki Pref. [Southern Ibaraki Prefecture] (maximum intensity: 3).
d) Intensified seismic activity, including an M3.9 earthquake on 4 December, occurred on the border of Chiba and Ibaraki Prefs. [Northeastern Chiba Prefecture].
e) Intensified seismic activity, including an M4.2 earthquake on 21 December, occurred in the sea near Niijima and Kozushima Islands (maximum intensity: 3).
f) A deep-focus M5.6 earthquake occurred on 31 December offshore of western Ishikawa Pref. [Central Japan Sea].
Note: Within square brackets ([ ]) is the epicenter place name used by the Meteorological Agency in its information releases.

Japan Meteorological Agency,Science and Technology Agency

Seismic Activity in Japan December 1999