14 July 1999
Headquarters for Earthquake Research Promotion
Earthquake Research Committee

Seismic Activity in Japan June 1999


1 Major Seismic Activity

* There was no marked activity.

2 Seismic Activity in each Region


(1) Hokkaido Region

* A magnitude (M) 5.1 earthquake occurred on 15 June southeast off the coast of the Nemuro Peninsula at a depth of about 40 km. This event occurred in an area adjacent to the aftershock zone of the 1994 earthquake (M8.1) offshore of eastern Hokkaido.

* An M4.3 earthquake occurred on 15 June in south-central Kushiro Administrative District at a depth of about 90km. This event occurred in the aftershock zone of the 1993 earthquake (M7.8) offshore of Kushiro.

(2) Tohoku Region

* There was no marked activity.

(3) Kanto-Chubu Region

* An M4.1 earthquake occurred on 27 June in southern Ibaraki Prefecture (Pref.) at a depth of about 50km. This event occurred in the vicinity of the boundary between the Philippine Sea plate and the continental plate.

* Seismic activity in central Mie Pref. that began in late January continues, sometimes diminishing and sometimes intensifying.

* The results of GPS observation in the Tokai (Shizuoka-Aichi-Gifu) area showed no marked variation.

(4) Kinki-Chugoku-Shikoku Region

* There was no marked activity.

(5) Kyushu-Okinawa Region

* There was no marked activity.

3 Addenda

* An M6.1 earthquake occurred on 3 July in the sea near Chichijima Island at a depth of about 450km.