Over 150 people were injured in an earthquake with a magnitude of 6.8, which rocked Niigata prefecture of central western Japan and surrounding areas on Monday morning.
According to Kyodo News, of the 150 injured people, more than 100 were taken to hospitals in Kashiwazaki in Niigata after the 10:13 a.m. (0113 GMT) quake. In nearby Nagano prefecture, at least four people suffered injuries.
The weather service issued a tsunami warning immediately after the quake and relieved it about an hour later. More than ten aftershocks were registered from 10:34 a.m. (0134 GMT) to 12:29 a.m. (0329 GMT) in Niigata, with magnitudes around 3 on the Richter scale, according to Japan Meteorological Agency.
The agency revised the major quake from 6.6 to 6.8 magnitude later at noon. The epicenter of the quake was around 17 kilometersbelow seabed in waters off Niigata prefecture, the agency said.
An electric transformer caught fire at the No. 3 reactor of Tokyo Electric Power Co.'s Kashiwazaki-Kariwa nuclear plant. The fire was brought under control around noon, local reports said. Other three reactors at Kashiwazaki-Kariwa nuclear plant automatically shut down.
The quake also caused power failures in over 21,700 houses in Niigata as of 11 a.m. (0200 GMT).
East Japan Railway Co. said it halted bullet train services on the Tohoku, Joetsu and Nagano Shinkansen lines as well as other train services. It said the Tohoku and Nagano Shinkansen lines later resumed operations.
Several parts of highway in Niigata were also closed after the quake. Niigata airport shut down its runways immediately after thequake to check for damage, airport officials said.
The government has set up an emergency management center to handle the quake. Prime Minister Shinzo Abe, who has been in Kyushu of southern Japan, is on his way back to Tokyo due to the quake, local reports said.
The quake measured upper 6 on the Japanese seismic intensity scale of 7 in Kashiwazaki and Kariwa in Niigata and Iizuna in Nagano, lower 6 in Joetsu and Nagaoka in Niigata, and upper 5 in Iiyama in Nagano. The earthquake also affected nearby prefectures including Ishikawa, Yamagata, Tochigi, Saitama, Fukushima and others.