Earthquake Off-shore of the Kaetsu Region, Niigata Prefecture on January 3

On January 3, 2011 at 13:45 (JST), there was a M4.7 earthquake (maximum seismic intensity 4) at a depth of 12km, off-shore of the Kaetsu region, Niigata prefecture. The focal mechanism showed a reverse fault with a compression axis in a NW-SE direction. As of the end of January, there has been no aftershock with seismic intensity of 1 or over.
For the seismic activity since October 1997, in the vicinity of the recent event (Area a), there have been no earthquakes over M4.0.

For the seismic activity since August 1923, in the vicinity of the recent event (Area b), the Niigata Earthquake occurred in 1964. This event caused damage with 26 fatalities, 447 injured people and 1960 completely collapsed houses (Comprehensive Bibliography of Destructive Earthquakes in Japan, Latest Edition). In addition, the tsunamis were observed along the Japan Sea coast from Hokkaido through the Chugoku regions, and the tsunami height reached to 3 to 5 m in the vicinity of the earthquake source (Seismicity of Japan).
In the vicinity of the recent event (Area b), earthquakes over M6.0 are only this Niigata Earthquake and its aftershocks.

Japan Meteorological Agency
[Seismic Activity for January 2011 (February 9, 2011)]