Earthquake in the Southern Oita Prefecture on October 22

[Hyuganada] is the regional name of the epicenter used in the Japan Meteorological Agency announcement.

On October 22, 2016 at 03:33 (JST), there was a M4.4 earthquake (maximum seismic intensity 4) at a depth of 55 km under the southern Oita prefecture. The focal mechanism had a tension axis in an NW-SE direction. This event occurred within the Philippine Sea plate.
For the seismic activity since October 1997, in the vicinity of the recent event (Area b), there were 3 earthquakes of M4.0 or over. Of these, a M5.7 earthquake (maximum seismic intensity 5 Upper) on July 13, 2015 caused damage with 3 injured persons, 3 partially-collapsed houses and so on.
For the seismic activity since January 1923, in the region around the recent event (Area c), there were 2 earthquakes of M7.0 or over. The 1968 Hyuganada Earthquake (M7.5, maximum seismic intensity 5) caused damage with 57 injured persons, 7,383 partially-collapsed houses, and so on. Also it caused tsunami with maximum total amplitude 236 cm observed at Tosa-Shimizu, Kochi prefecture. A M7.1 earthquake (maximum seismic intensity 4) on August 7, 1984 caused damage with 9 injured persons and 29 partially-collapsed houses (Comprehensive Bibliography of Destructive Earthquakes in Japan).

Japan Meteorological Agency
[Evaluation of Seismic Activities for October 2016 (November 10, 2016)]