A 7.4-magnitude earthquake struck off the northern coast of Japan on April 20, 2026, at 4:53 p.m. local time. The epicentre was located near Sanriku in the Pacific Ocean at a depth of 10 kilometres. The Japan Meteorological Agency (JMA) issued a tsunami warning for coastal areas including Iwate, Aomori, and Hokkaido prefectures.
Earthquake Characteristics
The earthquake measured 7.4 on the Richter scale and occurred at a shallow depth of 10 kilometres. It caused strong tremors felt as far as Tokyo, several hundred kilometres from the epicentre. The seismic activity was sufficient to sway buildings in distant urban areas.
Tsunami Warnings and Observations
The JMA forecasted tsunami waves up to 3 metres in height for affected coastal regions. An 80-centimetre tsunami wave was recorded at Kuji port in Iwate prefecture at 5:34 p.m. local time. Earlier waves of 70 centimetres and 40 centimetres were also observed at different ports in Iwate. Authorities warned of repeated tsunami waves and advised residents to remain on higher ground until warnings are lifted.
Safety Measures and Impact
Prime Minister Sanae Takaichi directed immediate evacuation of residents in coastal and riverside areas. An emergency task force was established to coordinate response efforts. No abnormalities were reported at nuclear power plants in Aomori and Miyagi provinces, which are currently offline. Bullet train services on the Tohoku and Akita Shinkansen Lines were suspended for safety inspections. Japan is located in a seismically active zone known as the Pacific Ring of Fire. The country has a comprehensive tsunami warning system managed by the JMA. Tsunami waves are generated by undersea earthquakes that displace large volumes of water.
Last Modified: April 20, 2026