A strong earthquake of preliminary magnitude 5.7 struck central Japan early Sunday, prompting authorities to set up an emergency response office. Japanese media reported that dozens of people were injured in the tremor.The earthquake struck at 1:04 am local time, with its epicentre in the western part of Shizuoka Prefecture at a depth of approximately 40 kilometres, according to the Japan Meteorological Agency (JMA), as reported by Japanese daily The Mainichi.The tremor registered an intensity of upper 5 on Japan's seismic intensity scale in Chita, Aichi Prefecture. Lower 5 intensity was recorded in parts of Aichi, Nagano and Gifu prefectures, indicating that the shaking was felt across a wide area of central Japan.Smaller aftershocks followed the main earthquake, according to reports. The Japanese government also established a liaison office to coordinate its response and assess the situation in the affected areas.The JMA said the earthquake posed no tsunami threat.According to a report by The Times of India, dozens of people were reportedly injured following the earthquake. The tremors affected a wide area around Aichi Prefecture, with residents in neighbouring regions also experiencing the shaking.Authorities are continuing to monitor seismic activity following the main tremor, while the possibility of further aftershocks remains a concern. No tsunami threat has been reported by the JMA.