By Tim Kelly and Chang-Ran Kim
TOKYO - A powerful earthquake struck central Japan on Monday, triggering warnings for residents to evacuate some areas on its west coast, knocking out power to thousands of homes and disrupting flights and rail services to the affected region.
The quake with a preliminary magnitude of 7.6 triggered waves of around 1 metre along parts of the Sea of Japan coast with a larger wave expected, public broadcaster NHK reported.
The Japan Meteorological Agency (JMA) has issued tsunami warnings for the coastal prefectures of Ishikawa, Niigata and Toyama, marking the first major warnings since the March 2011 earthquake and tsunami that struck northeastern Japan.
A major tsunami warning means there is a possibility of waves of more than 3 metres (9.84 ft).
Russia also issued tsunami warnings in its far eastern cities of Vladivostok and Nakhodka.
Some houses have been destroyed and army units have been dispatched to help with rescue operations, top government spokesperson Hayashi Yoshimasa told reporters, adding that authorities were still assessing the extent of the damage.
More strong quakes in the area, where seismic activity has been simmering for more than three years, could occur over coming days, JMA official Toshihiro Shimoyama said.
In comments to the press shortly after the quake struck, Prime Minister Fumio Kishida also warned residents to prepare for more disasters.
"Residents need to stay on alert for further possible quakes and I urge people in areas where tsunamis are expected to evacuate as soon as possible," Kishida said.
"Run!" a bright yellow warning flashed across television screens advising residents in specific areas of the coast to immediately evacuate their homes.
Images carried by local media showed a building collapsing in a plume of dust in the coastal city of Suzu and a huge crack in a road in Wajima where panicked-looking parents clutched their children. The quake also jolted buildings in the capital Tokyo, some 500 km from Wajima on the opposite coast.
More than 36,000 households had lost power in Ishikawa and Toyama prefectures, utilities provider Hokuriku Electric Power (9505.T) said.
High speed rail services to Ishikawa have been suspended while telecom operators Softbank (9434.T) and KDDI (9433.T) reported phone and internet service disruptions in Ishikawa and Niigata, according to their websites.
Japanese airline ANA (9202.T) turned back planes headed to airports in Toyama and Ishikawa, while Japan Airlines (9201.T) cancelled most of its services to Niigata and Ishikawa regions and authorities said one of Ishikawa's airports was closed.
Japan’s Nuclear Regulation Authority said no irregularities have been confirmed at nuclear power plants along the Sea of Japan, including five active reactors at Kansai Electric Power’s (9503.T) Ohi and Takahama plants in Fukui Prefecture.
Hokuriku's Shika plant in Ishikawa, the closest nuclear power station to the quake’s epicentre, had already halted its two reactors before the quake for regular inspections and saw no impact from the quake, the agency said.
The 2011 earthquake and tsunami killed nearly 20,000 people and devastated towns and nuclear meltdowns in Fukushima.
Another quake, known as the Great Hanshin Earthquake, hit western Japan in 1995, killing more than 6,000 people, mainly in the city of Kobe.
Monday's quake struck during the Jan. 1 public holiday when millions of Japanese traditionally visit temples to mark the new year.
In Kanazawa, a popular tourist destination in Ishikawa, images showed the remnants of a collapsed torii gate strewn at the entrance of a shrine as anxious worshippers looked on.
Kanazawa resident Ayako Daikai said she had evacuated to a nearby elementary school with her husband and two children soon after the earthquake hit. Classrooms, stairwells, hallways and the gymnasium were all packed with evacuees, she said.
"I also experienced the Great Hanshin Earthquake, so I thought it would be safest to evacuate," she told Reuters when contacted by telephone.
"We haven't decided when to return home yet."