June 14, 2008
Earthquake Research Committee,
Headquarters for Earthquake Research Promotion
* On June 14, at 08:43 (JST) there was a M7.2 (provisional) earthquake at a depth of approximately 10km under the southern inland area of Iwate prefecture. This event had a maximum seismic intensity 6 Upper in Iwate and Miyagi prefectures, and caused some damage. The focal mechanism showed a reverse fault with a compression axis in a WNW-ESE direction. This event occurred at a shallow location within the crust. Seismic activity is a mainshock-aftershock sequence. The largest aftershock as of 19:00 on June 14 was a M5.6 (preliminary) event at 09:20 on June 14 that had a maximum seismic intensity 5 Lower.
* Associated with this event, large accelerations were recorded, such as 1,055gal observed at the Ichinoseki-higashi station (E-W component) in Iwate prefecture.
* According to the GPS data, crustal movements associated with the mainshock were observed in the vicinity of this event, with a displacement of approximately 29cm (preliminary) to the ESE in Yuzawa city, Akita prefecture, and a displacement of approximately 19cm (preliminary) to the NW in Kurihara city, Miyagi prefecture.
* From the analysis of the focal process of the mainshock and the aftershock distribution, it is thought that the rupture propagated from the middle portion of the focal region toward both the SSW and to the NNE.
* Contiguously located northeast of the focal region is the Kitakami-Teichi-Seien Fault Zone. An Earthquake Research Committee evaluation gives the possibility that the entire fault zone could slip in one earthquake, producing a M7.8 event. It remains to be seen whether the fault zone is related to the recent event.
# Japan Meteorological Agency named this earthquake the Iwate-Miyagi Nairiku Earthquake in 2008.