A fairly strong earthquake hit Kyushu, western Shikoku and the southwestern tip of Honshu at around 9:32 a.m. Thursday, the Meteorological Agency said.
The quake, described as fairly strong, measured an estimated 4.9 on the Richter scale, the agency said. No tsunami warning was issued.
On the Japanese intensity scale, which goes to 7, the quake registered a lower 5 in Tomiai and Kashima in Kumamoto Prefecture.
It registered 4 in the cities of Kumamoto and Matsubase in Kumamoto Prefecture, and 3 in Unzen in Nagasaki Prefecture, Yatsushiro in Kumamoto Prefecture, Saiki in Oita Prefecture, and Takachiho in Miyazaki Prefecture, it said.
The focus of the quake was estimated to be some 10 km below the surface in Kumamoto Prefecture, the agency said.
There were no immediate reports of casualties from the quake. Police said windows in houses were broken, but no severe damage was reported in Kumamoto Prefecture.
Railroad and highway traffic was suspended by the quake, but Kumamoto airport was not affected.
A weaker earthquake, apparently an aftershock, struck Kumamoto at around 10:05 a.m., registering 2 in Tomiai.