Japan warns of possible megaquake after powerful earthquake, raising fears of possible 30-meter tsunami

Japan issued a megaquake warning on Tuesday after a magnitude of 7.5 earthquake It hit the northern part of the country, causing 34 injuries, mostly minor, and some damage to roads and buildings. The government has estimated that an offshore megaquake could trigger a tsunami of up to 30 meters and kill nearly 200,000 people.

Officials said the warning is not a prediction and that the probability of an earthquake of magnitude 8 or greater is only about 1%. But there are hopes that the warning will serve as a wake-up call for an earthquake that could devastate the 2011 disaster which killed almost 20,000 people and destroyed a nuclear plant.

There is said to be an increased risk of a subsequent earthquake of magnitude 8 or greater over the next week. Authorities are urging residents, especially in coastal areas, to be well prepared so they can grab an emergency bag and run as soon as possible if a major earthquake hits.

This ad seemed conscious compared to another ad from last year. The southern half of Japan’s Pacific coast received a “Nankai Trough” megaearthquake warning in the summer 2024but the ambiguity of that warning led to panic buying of emergency food, event cancellations and business closures.

Megaquake warning in Japan after a powerful earthquake

The Japan Meteorological Agency said Monday’s powerful earthquake struck off the eastern coast of Aomori, the northernmost prefecture of Japan’s main island of Honshu and just south of the northern island of Hokkaido.

Daiki Shimohata, 33, a civil servant from Hashikami on the island of Honshu, told Agence France-Presse that he and his family ran out of their house.

“The shaking was something we had never experienced. It lasted maybe 20 seconds,” Shimohata said by phone.

“We had our children, a 2-year-old girl and a 1-year-old boy, in our arms. The tremors reminded me of the disaster (in 2011),” she said.

The earthquake temporarily increased potential risks in the Hokkaido and coastal Sanriku regions. That’s where the Pacific Plate beneath Japan forms the two trenches (the Japan Trench and the Chishima Trench) that have caused many large earthquakes in the past.

Experts say the deadly 2011 earthquake and tsunami were caused by movement associated with the Japan Trench. It extends from the eastern coast of Chiba to Aomori, and the Chishima Trench runs from the eastern coast of Hokkaido to the northern islands and the Kuril Islands.

Explaining the advisory, the JMA said the magnitude 9.0 earthquake on March 11, 2011, which devastated large swaths of Japan’s northern coast, occurred two days after a magnitude 7.3 tremor that struck the Japan Trench off the eastern coast of Iwate, one of the areas hardest hit by that disaster, as well as Monday’s earthquake.

The 2011 earthquake triggered a tsunami that hit northern coastal cities in Iwate, Miyagi and Fukushima prefectures. The tsunami, which exceeded 50 feet in some areas, struck and destroyed the Fukushima Daiichi nuclear power plant. that created deep radiation fears that last to this day.

Megaearthquake could cause a 30-meter tsunami and kill almost 200,000 people

Another offshore megaquake in the Hokkaido-Sanriku area could cause a tsunami of up to 98 feet in the region, killing up to 199,000 people, destroying up to 220,000 homes and buildings, and causing economic damage estimated at up to 31 trillion yen ($198 billion), according to a government estimate. Up to 42,000 people could suffer hypothermia in winter.

The areas covered by the advisory extend across 182 municipalities from Hokkaido to Chiba Prefecture.

Japan’s separate warning for an even more damaging megaquake stemming from the Nankai Trough, affecting the southern half of Japan’s Pacific coast, was first activated last August after a magnitude 7.1 earthquake struck off the eastern coast of Miyazaki.

In a 2013 damage estimate for a possible Nankai Trough megaquake, the government said a magnitude 9.1 earthquake could generate a tsunami of more than 33 feet in a matter of minutes, killing up to 323,000 people, destroying more than 2 million buildings and causing economic damage exceeding 200 trillion yen ($1.28 trillion) in the region.

Officials call on people to be calm and prepared

Officials are emphasizing that the latest advisory does not have any prediction of any megaquake occurring at a specific time or location, a Cabinet disaster prevention official, Tsukasa Morikubo, said at a news conference early Tuesday. He called on residents to be cautious and prepared to continue with their daily activities and work.

Authorities urge people to have an emergency bag containing essential items for a few days, along with shoes and helmets. Residents of the region are also advised to discuss evacuation procedures with family members and to sleep in day clothes, not pajamas, so they can flee immediately. Furniture should also be fixed to the floor or wall.

The designated municipalities explained the notice on their websites and began inspecting stocks of relief goods and equipment to be used in evacuation centers.

The city of Iwaki in Fukushima urged residents to sign up for emergency emails, while officials in the city of Oarai in Ibaraki prefecture, northeast of Tokyo, inspected wireless communication devices.

Japan’s first megaquake warning in August last year contained a lot of scientific jargon. It worried and baffled many across the country. Some cities closed beaches and canceled annual events, disappointing many travelers during Japan’s Buddhist holidays.

Many people postponed their planned trips and rushed to stock up on rice, dry noodles, bottled water and portable toilets, leaving the shelves of many supermarkets in western Japan and even in Tokyo, which is outside the risk zone, empty.