Earthquake in the Chikugo Region, Fukuoka Prefecture on November 4

On November 4, 2004, at 03:13 (JST), there was a M4.2 earthquake at a depth of 14km in the Chikugo region, Fukuoka prefecture (maximum seismic intensity 4). The focal mechanism showed a normal fault with a tension axis in a NNW-SSE direction, which is commonly seen in this region. In this region, there are areas with clustered activity and relatively steady seismic activity is observed. After the recent earthquake, there was no remarkable aftershock activity. Seismicity is at a normal level.
For the seismic activity in this vicinity (Area b) since August 1923, the largest event was a M5 class earthquake. In addition, it is known that there was some damage caused by M6 class earthquakes in the 1800fs (a M6.1 in 1831, a M5.9 in 1848) near the border of Fukuoka and Saga prefectures.

Japan Meteorological Agency