A powerful 7.1-magnitude earthquake struck Kumamoto Prefecture in Japan’s Kyushu region on Tuesday, triggering tsunami advisories, transit suspensions, and power outages. Prime Minister Sanae Takaichi urged residents to remain vigilant for potential aftershocks of similar strength as emergency crews assess building damage and fires.
Kumamoto Prefecture Hit by Shindo 7 Tremor and Tsunami Advisories
A strong magnitude 7.1 earthquake struck Japan’s southern Kumamoto Prefecture at 4:35 p.m. local time on Tuesday, registering up to shindo 7 on the Japanese seismic intensity scale. The Japan Meteorological Agency issued tsunami advisories for coastal areas of the Ariake and Yatsushiro seas, urging residents to stay away from the coast as waves of approximately 1 meter were anticipated. The JMA plans to hold a news conference at 5:30 p.m. Germany’s GEOFON initially measured the quake at magnitude 6.4 before revising it to 6.8, while the US Geological Survey stated the quake struck at a depth of 10 kilometers (6.2 miles) at 4.28 pm local time (0728GMT).
A rare shindo 7 was observed in the cities of Uki and Hikawa. At that level, people cannot stay standing and may be thrown into the air, while unsecured pieces of furniture are likely to topple over or be tossed up in the air, and reinforced concrete walls may collapse. A strong 6 on the shindo scale was observed in the cities of Yatsushiro, Uto and the towns of Mashiki and Misato, as well as the city of Kumamoto’s Minami Ward. Other cities in Kumamoto, as well as the neighboring prefectures of Nagasaki, Kagoshima, Fukuoka, Saga and Miyazaki, also felt strong shaking of a lower 5 or stronger on the Japanese scale. The Japanese government issued emergency earthquake warnings for Kumamoto, Nagasaki, Kagoshima, Fukuoka, Saga, Oita, and Miyazaki prefectures, all on Japan’s southern Kyushu island.
Footage taken from an NHK helicopter at around 5:30 p.m. shows flames and smoke emerging from what appears to be a residential building in Uki City. The headquarters of the fire department responsible for the area including Kumamoto Prefecture’s Uki City says it has received many calls after the powerful shaking, and it is now checking the situation. Prefectural police in Kumamoto are also collecting information about damage. Japan’s Cabinet Office Disaster Management Division said a tsunami advisory had been issued for the Ariake and Yatsushiro seas, urging residents to leave coastal areas immediately and stay away until the advisory is lifted. There were no immediate reports of casualties or damage.
Long tremors capable of rocking high-rise buildings have been recorded in the region, which the JMA calls long-period ground motion.
It affects people on higher floors through a four-level intensity scale, featuring Class 4 shaking in the Kumamoto region—which is so strong it can be impossible to move without crawling—and Class 3 tremors making it difficult to remain standing, which were felt in Amakusa and Ashikita regions in Kumamoto Prefecture and can be strong enough to topple furniture. Around half an hour after the quake, a local NHK staffer wearing a helmet reported live on air that the shaking was continuing, with the newsroom shaking so violently it was difficult to remain standing. Shaking is continuing as I speak. Including myself, there may be some people who feel their hearts racing,
he said, adding, When the quake struck, the shaking was so big that I could not stand up. Please be aware of possibility that shaking might continue after this.
Government Response and Nuclear Plant Status
In a post to X, Prime Minister Sanae Takaichi urged those in the quake-hit areas to remain vigilant for the possibility of another earthquake of similar magnitude,
adding that the government was working to assess the extent of damage as quickly as possible.
At a hastily organized news conference, the government’s top spokesman warned that tsunami waves of approximately 1 meter were expected. Chief Cabinet Secretary Minoru Kihara also said that no abnormalities had been detected at the country’s nuclear power plants, including the Sendai facility in Satsumasendai, Kagoshima Prefecture.
Utility operators and transportation networks responded immediately to the disaster. About 45,000 households and facilities have no power in the Kumamoto region, according to local utility Kyushu Electric Power. The firm added that three nuclear reactors operating at the time in the region were continuing their normal operations. Kyushu Railway Company says services have been suspended on all of its trains, including the Kyushu Shinkansen, due to the quake.
Power plant operators maintained that safety systems held firm against the tremor. Kyushu Electric Power says it has not yet found any abnormalities at either the Genkai Nuclear Power Station in Saga Prefecture or the Sendai Nuclear Power Station in Kagoshima Prefecture, and also says radiation levels around the stations have not changed.
Seismic Context and Ongoing Aftershocks
An aftershock of up to a weak 5 hit the same area about 30 minutes later as authorities urged residents to remain vigilant for more large quakes.
Japan is one of the world’s most seismically active countries, sitting on top of four major tectonic plates along the western edge of the Pacific “Ring of Fire”. The archipelago, home to around 125 million people, typically experiences hundreds of jolts every year and accounts for about 18% of the world’s earthquakes, or about 20 percent of the world’s earthquakes of magnitude 6.0 or more, with a tremor occurring at least every five minutes. The vast majority are mild, although the damage they cause varies according to their location and the depth below the Earth’s surface at which they strike. It is haunted by the memory of a massive 9.0-magnitude undersea quake in 2011, which triggered a tsunami that killed or left missing around 18,500 people and wrecked the Fukushima nuclear plant.
In 2016, Kumamoto was hit two devastating earthquakes – one of magnitude 6.5, followed two days later by one of magnitude 7.3 – which killed 273 people and injured more than 2800 others. A quake with a magnitude of 7.2 hit northern Japan on June 25 but caused no deaths or major damage. On April 20 this year, a tremor measuring 7.7 hit the country’s north, injuring at least 10 people and shaking large buildings in Tokyo. This prompted authorities to issue a special advisory warning of an increased risk of earthquakes of magnitude 8.0 or stronger. The advisory was lifted after a week.
