* Magnitude 7.4 quake strikes near Japan coast early Tuesday
* Waves up to 1.4 m observed at Sendai before warnings
* JMA had warned of tsunami up to 3m, towns evacuated
* Cooling system for spent fuel briefly halted at nuclear
* Region affected is the same devastated by 2011 quake,
(Adds quote from teacher, updates financial markets, paragraphs
By Yuka Obayashi and Elaine Lies
TOKYO, Nov 22 A powerful earthquake rocked
northern Japan early on Tuesday, briefly disrupting cooling
functions at a nuclear plant and generating a small tsunami that
hit the same Fukushima region devastated by a 2011 quake,
tsunami and nuclear disaster.
The magnitude 7.4 earthquake, which was felt in Tokyo, sent
thousands of residents fleeing for higher ground as dawn broke
along the northeastern coast.
There were no reports of deaths or serious injuries hours
after the quake hit at 5:59 a.m. (2059 GMT Monday). It was
centred off the coast of Fukushima prefecture at a depth of
about 10 kilometres (6 miles), the Japan Meteorological Agency
A wave of up to 1.4 metres (4.5 ft) high was recorded at
Sendai, about 70 km (45 miles) north of Fukushima, with smaller
waves hitting ports elsewhere along the coast, public
broadcaster NHK said.
Television footage showed ships moving out to sea from
harbours as tsunami warnings wailed after alerts of waves of up
to 3 metres (10 feet) were issued.
"We saw high waves but nothing that went over the tidal
barriers," a man in the city of Iwaki told NTV television
Aerial footage showed tsunami waves flowing up rivers in
some areas, and some fishing boats were overturned in the port
of Higashi-Matsushima before the JMA lifted its warnings.
The U.S. Geological Survey measured Tuesday's quake at
magnitude 6.9, down from an initial 7.3.
All Japan's nuclear power plants in the area have been shut
down in the wake of the March 2011 disaster, which knocked out
cooling systems at Tokyo Electric Power Co's Fukushima
Daiichi nuclear plant, causing reactors to melt down and spew
radiation into the air, soil and sea.
The cooling system for a storage pool for spent nuclear fuel
at the reactor at its Fukushima Daini Plant was initially halted
on Tuesday, said a spokeswoman for Tokyo Electric Power, known
as Tepco, but was restarted soon after.
Only two reactors are operating in Japan, both in the
southwest. Nuclear plants need cooling systems operating even
when in shutdown to keep spent fuel cool.
Tohoku Electric Power Co said there was no damage
to its Onagawa nuclear plant, while the Kyodo news agency
reported there were no irregularities at the Tokai Daini nuclear
plant in Ibaraki prefecture.
Japanese Minister for Disaster Management Jun Matsumoto told
reporters there had been no reports of significant injuries. One
woman suffered cuts to her head from falling dishes, Kyodo
reported, citing fire department officials.
Earthquakes are common in Japan, one of the world's most
seismically active areas. Japan accounts for about 20 percent of
the world's earthquakes of magnitude 6 or greater.
The March 11, 2011, quake was magnitude 9, the strongest
quake ever recorded in Japan. The massive tsunami it generated
knocked out the Fukushima Daiichi plant, causing the worst
nuclear crisis since Chernobyl a quarter of a century earlier.
Systems have been updated since the 2011 disaster to spread
warnings more quickly, said Tsunetaka Omine, head of the
Disaster Management Division in Iwaki, a city in Fukushima
Previously, there were complicated directions on where to
evacuate. "But now, we basically just tell people to head away
from the sea, to the highest possible ground," Omine said.
Authorities now also send tsunami warnings to every mobile
phone in the area and broadcast on local radio.
Staying in a traditional Japanese inn on the coast in the
city of Ofunato with a dozen international high school students
on a study tour, teacher Kathy Krauth said the shaking began
just seconds after a quake alarm on her phone went off.
"I felt like the lessons of 3-11 were really taken to
heart," said Krauth, who teaches a class on the March 2011
disaster and its aftermath. "The feeling was, we just don't
know, but we're going to be as cautious as we can."
Nissan Motor Co said it would suspend work at its
engine factory in Fukushima at least until the latest tsunami
warning was lifted. A spokesman said there were no injuries or
damage at the plant, which was badly damaged in the 2011
Toyota Motor Corp said all its factories in
northeastern Japan were operating as usual.
Japan's famous Shinkansen bullet trains were halted along
one stretch of track and some other train lines were also
Japanese financial markets were little affected, with the
Nikkei 225 index closing up 0.3 percent and the yen
steady against the U.S. dollar.
(Additional reporting by Chris Gallagher, Jon Herskovitz, Osamu
Tsukimori, Aaron Sheldrick and William Mallard; Writing by
Lincoln Feast; Editing Paul Tait)