At least 20 people were injured after a 5.7-magnitude earthquake struck central Japan early Sunday, local media reported. Injuries were reported in Aichi and Shizuoka prefectures, Tokyo-based Kyodo News reported, citing local authorities. No tsunami warning was issued. The earthquake originated in the western part of Shizuoka prefecture at a depth of about 40 kilometres (25 miles), according to the Japan Meteorological Agency. The quake was the most severe in about three decades to hit Aichi. No abnormalities were detected at the Hamaoka nuclear power plant in Shizuoka, according to its operator, Chubu Electric Power Co. Read: Death toll from earthquake in southwestern Japan rises to 35 The quake forced authorities to suspend some local train services. A 4.3 magnitude earthquake hit the Kumamoto prefecture in southwestern Japan on Sunday morning. Japan, which sits on the Pacific Ring of Fire and directly atop four major tectonic plates, is one of the most seismically active countries in the world. Kumamoto experienced a magnitude 7.1 quake on July 28.