Magnitude 7.5 earthquake off Japan triggers tsunami warning for 3-metre waves

Authorities issued evacuation orders for coastal areas as tremor shook buildings hundreds of kilometres away in Tokyo.

A magnitude 7.5 earthquake struck off the northeastern coast of Japan on Monday afternoon, prompting authorities to issue a tsunami warning for waves up to 3 metres in height¹²³. The tremor occurred at 4:53 p.m. local time in Pacific waters off Iwate prefecture, with an epicentre 10 kilometres deep¹⁴.

The Japan Meteorological Agency warned that the biggest waves were expected in Iwate, Aomori and Hokkaido prefectures¹. The agency urged residents to evacuate immediately from coastal regions and riverside areas to higher ground, warning that tsunami waves were expected to hit repeatedly²³.

Prime Minister Sanae Takaichi said the government had set up a crisis management team and urged citizens in affected areas to evacuate to safety¹³. Japan's top government spokesperson Minoru Kihara told a news conference there were no immediate reports of casualties or major damage⁴.

Two hours after the tremor, tsunami waves as high as 80 centimetres had been detected, though warnings remained in place for potentially larger waves⁴. Several port towns including Otsuchi and Kamaishi, both severely affected by a massive earthquake and tsunami in 2011, issued evacuation orders for thousands of residents⁴.

Public broadcaster NHK showed ships sailing out of Hachinohe port in Hokkaido in anticipation of the waves as an alert flashed across screens¹. Bullet train services in Aomori, at the northern tip of Honshu island, were halted and some motorways were closed¹⁴.

The quake measured an upper 5 on Japan's seismic intensity scale, strong enough to make it difficult for people to move around and cause unreinforced concrete-block walls to collapse¹⁴. The tremor was felt across a wide area, shaking large buildings as far as Tokyo, hundreds of kilometres to the south²³.

Japan Meteorological Agency officials said big aftershocks may occur in the following days and weeks⁴. There were no nuclear power plants currently in operation in the Hokkaido and Tohoku regions¹, and no abnormalities were reported at idled nuclear facilities⁴.

Japan is one of the world's most earthquake-prone countries, located in the Ring of Fire of volcanoes and oceanic trenches partly encircling the Pacific Basin¹⁴. The country accounts for about 20 percent of the world's earthquakes of magnitude 6.0 or greater, with a tremor occurring at least every five minutes¹.