TOKYO - A minor tsunami hit large swathes of northeastern Japan early Saturday, including in a city near the crippled Fukushima nuclear plant, after a strong 6.8 magnitude earthquake struck off the country's Pacific coast.
There were no immediate reports of damage following the quake and tsunami, however, with authorities lifting all advisories roughly two hours later.
Much of the coastline covered by the advisories Saturday is still recovering from the 2011 quake and tsunami disaster that killed more than 18,000 people and triggered a meltdown at Fukushima.
A minor tsunami of 20 centimeters (7.8 inches) was observed in Ishinomaki, Miyagi prefecture, and Ofunato, Iwate prefecture, the Japan Meteorological Agency said Saturday.
Waves of 10 centimeters were also monitored in the city of Soma, roughly 40 kilometers (25 miles) north of the Fukushima Daiichi nuclear plant, the agency said. The city suffered severe damage in the 2011 disaster.
At least three people were injured by the quake in Fukushima, according to Japan's public broadcaster NHK, including a 68-year-old woman who suffered a broken leg.
Authorities had issued a tsunami advisory for Miyagi as well as neighboring Fukushima and Iwate prefectures, warning that a wave of up to one meter (3.3 feet) could impact their Pacific coastlines after the quake.
"We have lifted the tsunami advisory, but do not approach coastlines for now as there may be a change in sea levels," an agency official said.
- Evacuation advisories lifted -
Fukushima plant operators Tokyo Electric Power (TEPCO) said there were no reports of any abnormality early Saturday.
Sea levels cannot be gauged near the nuclear plant as the tsunami monitoring system was destroyed by the 2011 disaster.
"We have not seen any damage or any change in radiation gauges after the quake," said TEPCO spokesman Masahiro Asaoka.
"Today's operation has yet to start but we ordered workers to evacuate to high places," Asaoka told AFP.
"Our temporary breakwater that was newly built at the plant is high enough to block a one-metre tsunami," he added.
The local government in Kamaishi, Iwate prefecture, issued an evacuation advisory to some 12,000 residents, while other authorities in the region issued similar advisories, officials said.
All the evacuation advisories were later lifted.
The United States Geological Survey said the quake struck around 129 kilometers (79 miles) east south-east of the city of Namie, an estimated 284 kilometers east north-east of the capital Tokyo, at 4.22 am local time (1922 GMT Friday).
A meteorological agency official said the tremor, which the USGS placed at a depth of 13 kilometers (eight miles), was an aftershock from the 2011 quake.
The Fukushima plant's cooling systems were swamped by the tsunami three years ago, sparking reactor meltdowns and radiation leaks in the worst atomic crisis in a generation.
Tens of thousands of people were evacuated from around the plant, with decommissioning of the site expected to take decades.
The utility is struggling to handle a huge -- and growing -- volume of contaminated water.
On Friday, the crippled plant was skirted by tropical storm Neoguri. Workers had scrambled to insulate the plant from any storm damage, but Neoguri had little impact on the site as it headed out into the Pacific.
Japan is situated at the conjuncture of several tectonic plates and experiences a number of relatively violent quakes every year.
But thanks to strict building codes, even powerful quakes that might wreak havoc in other countries frequently pass without causing much damage.
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