In the 48 hours since Monday's earthquake 35 aftershocks have been registered, local media reported, adding that around 1,700 people have been evacuated.
The earthquake hit the Osaka prefecture and southern Kyoto prefecture at around 8:00 a.m. on Monday (23:00 GMT on Sunday).
The Japan Meteorological Agency said that the aftershocks might continue during this week.
According to Japanese media reports, gas supplies to over 100,000 households had been cut off as a result of the earthquake.
The earthquake also led to a temporary breakdown in the operation of railways. Takeoff and landing of planes at Osaka's Kansai International Airport were temporarily suspended during the quake as well.