Authorities are warning the public to remain vigilant for strong shaking over the next week, after Tokyo and the broader Kanto region were jolted awake at around 2 a.m. Sunday by a magnitude 5.9 earthquake.

The quake, which was centered in southern Ibaraki Prefecture and struck at a depth of 68 kilometers, was recorded at an intensity of lower 5 on Japan’s seven-point shindo seismic scale in Tokyo’s Adachi Ward, as well as in parts of Ibaraki, Saitama and Chiba prefectures. Level 4 shaking was recorded in other areas of Tokyo as well as Tochigi, Gunma and Kanagawa prefectures.

Lower 5 can cause objects to fall off shelves and force people to grab onto things to steady themselves, according to the Japan Meteorological Agency.

The shaking, lasting up to a minute in some areas, was felt shortly after earthquake early warning alarms sounded on mobile phones.

It left at least nine people hurt in Saitama Prefecture, eight people injured in Kanagawa Prefecture and caused a partial collapse of the ceiling at the Ushiku City Hall in Ushiku, Ibaraki Prefecture, according to NHK. Minor injuries were also reported in Tokyo, where fire officials said there had been reports of people trapped in elevators.

No tsunami alert was issued.

The quake also disrupted railway services, with JR East reporting delays across a number of train lines Sunday morning, including the Joban Line, Keihin Tohoku Line, Shonan Shinjuku Line, Musashino Line, Chuo-Sobu Line, Sotobo Line and others across Kanto.

Level 2 long-period ground motion was also observed in Tokyo’s 23 wards, as well as Saitama and Chiba prefectures. Long-period ground motion refers to slow, prolonged shaking that can cause high-rise buildings to sway significantly. At Level 2, people may have difficulty standing, and furniture or other objects may move or fall.

Within an hour of the quake, Prime Minister Sanae Takaichi wrote on X that efforts to confirm the extent of the damage were ongoing and that a liaison office had been established at the Prime Minister’s Office Crisis Management Center. She added that she had issued instructions for officials to provide timely and accurate information to the public.

“To those in the areas where the shaking was strong, I ask that you continue to remain vigilant for the possibility of another earthquake of similar magnitude,” the prime minister said.

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