April 12, 2011
Earthquake Research Committee,
Headquarters for Earthquake Research Promotion

Earthquake in Hamadori, Fukushima Prefecture on April 11, 2011

* On April 11 at 17:16 (JST), 2011, there was a M7.0 (preliminary) earthquake at a depth of approximately 5km in Hamadori, Fukushima prefecture. This event had a maximum seismic intensity 6 Lower in Fukushima and Ibaraki prefectures. There was an aftershock with a seismic intensity 6 Lower on April 12. The aftershock activity has been continuing. As of 16 o'clock, April 12, there have been 12 aftershocks with seismic intensity 4 or over.

* The focal mechanism showed a normal fault with a tension axis in a WSW-ENE direction. This is a shallow event that occurred within the crust.

* According to the GPS data, crustal movements associated with this event were observed, and there was a movement of approximately 30cm toward the northeast at the Iwaki-2 station (Fukushima prefecture).