The Chūetsu Earthquakes (中越地震 Chūetsu jishin) was a magnitude 6.8 earthquake which occurred in Niigata Prefecture, Japan, at 17:56 (local time) on Saturday, October 23, 2004 (08:56 UT, same day). The Japan Meteorological Agency (JMA) named it the "Heisei 16 Niigata Prefecture Chuetsu Earthquake" (平成16年新潟県中越地震 Heisei ju-roku-nen Niigata-ken Chuetsu Jishin ). Niigata Prefecture is located in the Hokuriku region of Honshu, the largest island of Japan. The initial earthquake caused noticeable shaking across almost half of Honshu, including parts of the Tohoku, Hokuriku, Chūbu, and Kantō regions.