Japan is on alert for a possible mega quake after a magnitude 7.5 tremor hit northern regions late on Monday, prompting tsunami warnings. Authorities say the next few days will be critical.
Strong tremors across the region
Monday’s earthquake struck off the eastern coast of Aomori Prefecture at around 11:15 p.m., with a depth of 54 kilometers.
The city of Hachinohe recorded tremors with an intensity of upper 6 on the Japanese intensity scale of 0 to 7.
Authorities in Hokkaido, Aomori and Iwate prefectures have reported 33 people injured, as of 5 p.m. on Tuesday.
‘Long-period ground motions’ recorded
The quake produced long-period ground motions — slow, wide-swinging seismic waves that can significantly impact high-rise buildings. In parts of Aomori Prefecture, they were strong enough to make it difficult for people in high-rises to remain standing.
Authorities initially issued tsunami warnings for Iwate Prefecture and parts of Hokkaido and Aomori, later downgrading them to advisories. They lifted all advisories by 6:20 a.m. on Tuesday.
Tsunami of 70 centimeters or less were observed in multiple locations.
‘Potential mega quake’
Japan’s Meteorological Agency, or JMA, says a major tremor of magnitude 8 or higher could occur along the Japan Trench and the Chishima Trench off Hokkaido.
The advisory covers areas from Hokkaido to Chiba Prefecture, and is the first issued for the region since the mega-quake warning category was introduced in 2022.
Officials are urging people to check evacuation routes, make sure home furniture is secure, and prepare emergency kits, including food, water and portable toilets.
They stress that no evacuation recommendation has been issued, but they advise people to remain vigilant through next week.
Morikubo Tsukasa, the Cabinet Office’s director for disaster management, said at a news conference that global earthquake data suggests there’s a possibility, not a prediction, of a larger tremor to come.
Morikubo: Based on the statistics of earthquakes that have occurred around the world so far, there is a possibility that a large-scale earthquake with a magnitude of 8 or higher could occur as a follow-up earthquake along the Japan Trench and the Chishima Trench off Hokkaido. It is unclear whether a large-scale earthquake will occur. But everyone should heed the call to take precautions to protect their own lives.
Fake-news warning
Chief Cabinet Secretary Kihara Minoru has urged people to use government sources or trusted media sites to stay up to date. He says misinformation has circulated after disasters in the past.
The Japanese government set up a task force at the crisis management center in the prime minister’s office. Prime Minister Takaichi Sanae said it is working to grasp the extent of the damage and will make every effort to respond.
Schools close, water outages
The education ministry says 7 public schools in Aomori Prefecture have reported damage, including broken windows. Across the prefecture, 139 schools closed on Tuesday due to the earthquake.
The infrastructure ministry says around 100 households in Aomori Prefecture were without running water at 1 p.m. on Tuesday.
Nuclear facilities report no abnormalities
Power companies with nuclear plants in the region say they have not detected any abnormalities.
Tokyo Electric Power Company says there are no abnormalities at both the Fukushima Daiichi and Daini nuclear plants, but it halted the release of treated and diluted water from Daiichi at 11:42 p.m. on Monday, as a standard precautionary measure.
The facility suffered a triple meltdown in the March 2011 earthquake and tsunami, and water used to cool molten fuel continues to mix with rain and groundwater. That water is treated to remove most radioactive substances, except tritium. It is then diluted, reducing levels of tritium to well below the World Health Organization’s guidance for drinking water, before it is released into the ocean.
TEPCO says it ordered some employees to temporarily evacuate from the plant.
Tohoku Electric Power Company says no irregularities have been detected at the Higashidori nuclear power plant in Aomori Prefecture or the Onagawa plant in Miyagi Prefecture.
Hokkaido Electric Power Company also reports no problems with its Tomari nuclear power plant.
Transport disruptions
Tohoku Shinkansen bullet train services were suspended on Tuesday between Morioka and Shin-Aomori stations, but resumed at 3:41 p.m.
All Nippon Airways, Japan Airlines and regional airline Airdo all say they are operating as usual.
Learning from the Great East Japan Earthquake
According to the government, the probability of a massive earthquake occurring within the next week is about one in a hundred.
Professor Sekiya Naoya of the University of Tokyo Graduate School says if such a disaster does occur, up to 200,000 lives could be lost. He urged people not to ignore this risk, but use the JMA’s advisory as a reminder to check their preparations.
