March 13, 2011
Earthquake Research Committee,
Headquarters for Earthquake Research Promotion
* On March 12 at 03:59 (JST), 2011, there was a M6.7 (preliminary) earthquake at a depth of approximately 10km, near the border between Nagano and Niigata prefectures. This event had a maximum seismic intensity 6 Upper in Sakae Village, Nagano prefecture. Since then, there have been large aftershocks such as two shocks with seismic intensity 6 Lower.
* The focal mechanism showed a reverse fault (preliminary) with a compression axis in a NNW-SSE direction. This shallow event occurred within the crust.
* According to the GPS data, crustal movements associated with this event were observed and there were movements of approximately 39cm toward the northeast at the Matsunoyama observation point (Niigata prefecture).