Japan issued a special advisory on Monday warning of an increased risk of a “huge” earthquake after a powerful 7.5 magnitude tremor struck off its northern coast, triggering tsunami alerts and evacuations.The quake hit off the Sanriku coast at around 4.53 pm local time at a depth of about 10 kilometers. A tsunami of about 80 centimeters was detected at Kuji port in Iwate prefecture within an hour, while another port recorded waves of about 40 centimeters.
Advisory warns of further risk
Following the quake, the Japan Meteorological Agency issued a special advisory, saying “the likelihood of a new, huge earthquake occurring is relatively higher than during normal times.” Officials stressed that the advisory is not a prediction but urged residents to remain prepared while continuing daily life.The Cabinet Office of Japan and the weather agency said there is a 1% chance of a mega-quake of magnitude 8.0 or stronger along the northern coast within the next week following the earlier tremor near the Chishima trough. A similar advisory was issued in December after another major quake, though no large event followed.
Evacuations and ground response
The magnitude 7.5 earthquake tremors were powerful enough to sway high-rise buildings as far away as Tokyo, several hundred kilometres from the epicentre.In Hokkaido, waves were seen swelling close to the shore, prompting residents to move to higher ground. Footage showed people evacuating to parks and elevated areas. In Tomakomai, one resident said he planned to stay on a hilltop with his child until the alert was lifted.Evacuation advisories were issued for more than 128,000 residents across Iwate and three other northern prefectures. Authorities urged people to stay away from coastal areas and rivers and warned of possible aftershocks for about a week.Alerts remained in place with warnings of waves up to 3 meters, though the Pacific Tsunami Warning Center later said the threat “has now passed.”
No major damage reported
Despite the scale of the quake, officials said no major injuries or damage had been reported, including at power stations. The Nuclear Regulation Authority confirmed that nuclear facilities were operating normally with no abnormalities.Transport services were disrupted, with several bullet train operations in northeastern Japan suspended. The Tohoku, Yamagata and Akita Shinkansen lines were among those affected, along with some services in Tokyo.
Japan’s seismic risk
Japan remains one of the world’s most seismically active countries, accounting for more than 10% of earthquakes globally with a magnitude of six or higher. On average, a magnitude 7 or stronger quake occurs about every 16 months.The latest developments come 15 years after the 2011 Tōhoku earthquake and tsunami, a magnitude 9.0 catastrophe that killed more than 22,000 people and displaced nearly half a million, many due to tsunami damage and the Fukushima nuclear crisis.