A magnitude 5.9 earthquake struck eastern Japan early on August 23, injuring more than 40 people in Tokyo and neighbouring prefectures and prompting the Japan Meteorological Agency to warn of further strong shaking in the coming days.

According to Kyodo News, the earthquake struck at about 2am, with its epicentre in southern Ibaraki prefecture to the northeast of the capital at a depth of 68km, the weather agency said. No tsunami was generated.

The quake registered lower 5 on Japan’s seven-point seismic intensity scale in parts of Ibaraki as well as central Tokyo. The level is considered strong enough to frighten most people and cause them to hold on to stable objects, while items can fall from shelves.

Train services were disrupted after the earthquake but being in the early hours minimum disruption was observed. Some services started late and others initially operated at reduced speeds, JR East and other railway operators said.

Keisei Line services between Ueno in northeast Tokyo and Narita airport in Chiba prefecture returned to normal after 9.40am. Some express services operated by Tobu Railway to the north of the city remained suspended.

Local fire departments reported injuries across several prefectures. More than 20 people were hurt, including a young man and a woman in her 70s in Saitama prefecture, north of Tokyo. Nine people were injured in Kanagawa and four in Chiba.

In Tokyo’s Koto Ward, a water pipe ruptured. Metropolitan authorities were investigating whether the damage was caused by the earthquake.

Lower 5 intensity was also recorded in parts of Saitama and Chiba. In Tokyo, Adachi Ward on the Arakawa River recorded the same level, while other parts of the capital experienced weaker shaking.

Operators reported no abnormalities at the Tokai No. 2 nuclear power plant in Ibaraki or at the Fukushima Daiichi and nearby Fukushima Daini nuclear plants in northeastern Japan.