Japan Meteorological Agency raises magnitude of quake to 7.3 from 7.1.
Strong tremors were also recorded in Tochigi, Iwate, Yamagata, Ibaraki, and Saitama prefectures.
A magnitude 7.1 earthquake struck northern Japan at 11:08 p.m. on Saturday, local time.Eight people are injured with latest report from Japan.
The quake registered a maximum intensity of six-plus on the Japanese scale of zero to seven. Two evacuation centre opened in Soma city.
No tsunami threat has been issued.

Earthquake, 23:07 JST on 13 Feb 2021, Seismic intensity 6+ at Southern Miyagi Prefecture. Epicenter:Off the Coast of Fukushima Prefecture, depth 60km, estimated magnitude 7.1.
An earthquake of magnitude 7.0 hit 90 km east-northeast of Namie, Japan:
Fire department officials in Fukushima City say there are reports that around eight people were injured in the earthquake.
Officials of Fukushima Prefecture say four people are injured in the prefecture. Latest updates.
Loss of life or damage to the property still not reported. No significant damage or casualties have been reported so far, and no irregularities were reported at any nuclear facilities, Japanese public broadcaster NHK said.
A strong magnitude 7.1 earthquake shakes Japan’s Fukushima province. There is no danger of a tsunami, authorities said.
Japan’s Nuclear Regulation Authority says it has received no reports of abnormalities at the Fukushima Daiichi and Daini nuclear power plants in Fukushima Prefecture.
A strong earthquake with a magnitude of 7.1 hit off the coast of eastern Japan, shaking buildings and triggering widespread power blackouts.