An earthquake with a preliminary magnitude of 5.2 jolted areas surrounding Tokyo Bay early Thursday, including Chiba Prefecture and downtown Tokyo, leaving several people injured, according to the Japanese weather agency and local authorities.
The 4:16 a.m. quake registered an upper 5 on the Japanese seismic intensity scale of 7 in Kisarazu and a lower 5 in Kimitsu, both in Chiba Prefecture, and a 4 in areas including Tokyo's Chiyoda and Shinagawa wards, according to the Japan Meteorological Agency. No tsunami warning was issued.
The agency defines upper 5 as a situation where many people find walking difficult. It was the first time since March 2012 that Chiba Prefecture had been rocked by an upper 5 quake, according to the agency.
In Kisarazu, roof tiles from three homes were dislodged and scattered on the ground, while windows in buildings had cracked from the shaking.
In Chiba Prefecture, five people in their 70s or older sustained minor injuries. Another two people were hurt in adjacent Kanagawa Prefecture, where a woman fell at home and a man was hit on the head by a light that fell from a shelf while he was sleeping.
There were no immediate reports of casualties in Tokyo.
Around 3,000 elevators in Tokyo and its vicinity, including Chiba Prefecture, stopped but did not result in anyone being trapped, Hitachi Building Systems Co., a major building facilities management company, said. Work to restart the elevators had almost been completed by 11 a.m.
Many elevators automatically stopped after detecting the temblor. Elevators in high-rise condominium buildings were mainly affected, according to Tokyo-based Elevator Systems Co.
Most train lines operated normally from their first services, and there was no major disruption for morning commuters.
The JMA warned that quakes with an intensity of up to 5 could occur for about a week.
The quake on Thursday measured 4 in Mihama Ward in the city of Chiba and some wards in Yokohama and Kawasaki, both south of Tokyo.
It originated in southern Chiba Prefecture at a depth of around 40 kilometers. The agency initially reported a magnitude of 5.4 but later revised it to 5.2.