At least 23 people were injured after a powerful magnitude 7.5 earthquake struck off northern Japan late Monday. The quake, occurring around 11:15 p.m., hit about 80 kilometres off the coast of Aomori prefecture. It triggered a tsunami in Pacific coast communities and raised emergency alerts. The Japan Meteorological Agency issued a tsunami warning, observing waves up to 70 centimetres hitting the northern region of Aomori. Later on Tuesday, the agency lifted the tsunami warning but kept some lower-level advisories for northern Japan before canceling those too. About 480 residents sheltered at Hachinohe Air Base. Defence Minister Shinjiro Koizumi said 18 defence helicopters were sent for damage assessment. NHK reported approximately 200 passengers were stranded overnight at New Chitose Airport in Hokkaido. The US Geological Survey noted a second quake of magnitude 5.1 early Tuesday near Honcho, south of the initial quake. The meteorological agency warned of possible aftershocks in the coming days. They also cautioned of a slightly increased risk of a major magnitude 8-level quake and tsunami along Japan’s northeastern coast from Chiba to Hokkaido. Residents in 182 municipalities were urged to stay prepared. Eyewitnesses described strong shaking and panic. Convenience store owner Nobuo Yamada said, “I’ve never experienced such a big shaking,” while Satoshi Kato, a high school vice principal, spoke of falling glass and traffic jams as people fled. Prime Minister Sanae Takaichi said the government has set up an emergency task force. She assured, “We are putting people’s lives first and doing everything we can.” She urged residents to follow local information and be ready to evacuate immediately if needed. The earthquake occurred near the area hit by the devastating 2011 magnitude 9.0 quake and tsunami, which caused massive destruction and loss of life.