At least four people died after a strong magnitude 7.5 earthquake shook Japan's western coastline on Monday, as the country issued tsunami alerts, urging citizens to evacuate the affected region, causing power outages in thousands of homes and disrupting flights and rail services to the disaster-hit region.
The magnitude 7.5 quake struck Ishikawa prefecture on the Sea of Japan side of the main island of Honshu at 4:10 p.m. (0710 GMT), according to the U.S. Geological Survey (USGS).
Japanese authorities put the magnitude at 7.6 and said that it was one of more than 50 quakes of 3.2 magnitude or more to rock the region on the New Year's Day holiday – when families get together and visit shrines – over several hours.
It issued a major tsunami warning for Ishikawa and lower-level tsunami warnings or advisories for the rest of the western coast of Japan's main island of Honshu.
Japanese public broadcaster NHK TV warned torrents of water could reach as high as 5 meters (16.5 feet) and urged people to flee to high land or the top of a nearby building as quickly as possible.
NHK said the tsunami waves could keep returning, and warnings were continuing to be aired more than an hour after the initial alert. Several aftershocks also rocked the region.
Government spokesperson Yoshimasa Hayashi told reporters that nuclear plants in the area had not reported any irregularities. But he said it was critical for people in coastal areas to get away from the oncoming tsunami.
"Every minute counts. Please evacuate to a safe area immediately," he said.
A tsunami of about 3 meters high was expected to hit Niigata and other prefectures on the western coast of Japan. Smaller tsunami waves were already confirmed to have reached the coastline, according to NHK.
The Japan Meteorological Agency has issued tsunami warnings for the coastal prefectures of Ishikawa, Niigata and Toyama. Russia also issued tsunami warnings in its far eastern cities of Vladivostok and Nakhodka.
In nearby South Korea, the weather agency urged residents in some eastern coastal towns to watch for possible changes in sea levels. Tsunami waves that hit later can be bigger than the initial ones.
Authorities are still assessing the extent of the damage and residents need to prepare for any more tremors, Prime Minister Fumio Kishida said in comments aired on NHK.
"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.
NHK TV footage showed a room shaken by the quake, with hanging laundry swaying from side to side and a computer on a desk rattling. Reports of major damage were not immediately available. NHK reported that some electric poles were toppled and roads were cracked.
More than 36,000 households had lost power in Ishikawa and Toyama prefectures, utilities provider Hokuriku Electric Power said.
High-speed rail services to Ishikawa have been suspended while telecom operators Softbank and KDDI reported phone and internet service disruptions in Ishikawa and Niigata, according to their websites.
Japanese airline ANA turned back four planes headed to airports in Toyama and Ishikawa midair after the quake, while Japan Airlines canceled most of the flight services to Niigata and Ishikawa regions for the rest of the day, according to TV Asahi.
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 Ohi and Takahama plants in Fukui Prefecture.
Japan is an extremely quake-prone nation. A huge earthquake and tsunami struck northeastern Japan on March 11, 2011, killing nearly 20,000 people, devastating towns and triggering nuclear meltdowns in Fukushima.