Minor tsunami hit Tohoku’s coastline early Saturday, including in a city near the crippled Fukushima nuclear plant, after a strong 6.8-magnitude earthquake struck off the Pacific coast.
There were no immediate reports of damage, however, and authorities lifted all advisories roughly two hours later.
The manager of the Fukushima No. 1 nuclear plant said no abnormal activity was reported after the quake, which a Meteorological Agency official said appeared to be an aftershock of the Great East Japan Earthquake on March 11, 2011.
According to the United States Geological Survey, the quake struck around 129 km (79 miles) east southeast of Namie, Fukushima Prefecture, at 4.22 a.m.
Many of the communities along the coastline covered by Saturday’s advisories are still recovering from the March 2011 quake and tsunami, which killed more than 18,000 people and triggered a triple core meltdown at the Fukushima No. 1 power plant.
Minor tsunami as high as 20 cm (7.8 inches) were observed in Ishinomaki, Miyagi Prefecture, and Ofunato, Iwate Prefecture, the Meteorological Agency said.
Tidal waves of 10 cm were also logged in the city of Soma, about 40 km (25 miles) north of the Fukushima No. 1 plant, the agency said. Soma was severely damaged by the natural and man-made disasters.
At least three people were injured by the quake in Fukushima, said NHK, including a 68-year-old woman who suffered a broken leg.
The tsunami advisories for Miyagi, Fukushima and Iwate prefectures warned that waves of up to 1 meter (3.3 feet) were possible.
“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.
Fukushima No. 1 manager Tokyo Electric Power Co. said there were no reports of abnormal activity at the plant early Saturday, but the sea levels near it cannot be gauged because the tsunami monitoring system was destroyed on 3/11.
“We have not seen any damage or any change in radiation gauges after the quake,” Tepco spokesman Masahiro Asaoka said.
“Today’s operations have yet to start but we ordered workers to evacuate to high places,” he said. “Our temporary breakwater that was newly built is high enough to block a 1-meter tsunami.”
The tsunami that hit the poorly protected plant in March 2011 measured about 14 meters, overwhelming its seawall, which was only about 10 meters high at the time.
The city of Kamaishi, Iwate Prefecture, issued an evacuation advisory to some 12,000 residents, as did other authorities in the region, officials said. All were later lifted.
The Fukushima No. 1 plant lost all electrical power after the quake and tsunami three years ago. After the waves swamped its cooling systems, three reactor cores melted, tainting much of the area with radiation in the worst nuclear disaster since Chernobyl.
Tens of thousands of people were evacuated from around the plant and the decommissioning process is expected to take decades.
In the meantime, the utility is struggling to handle a huge — and growing — volume of radiation-contaminated water that poses the next stage in the crisis.
On Friday, the crippled plant was skirted by tropical storm Neoguri, which had been a typhoon until wading through west Japan. Workers had scrambled to secure the plant from the storm, but Neoguri had little impact after heading into the Pacific.