A powerful earthquake struck off the northern coast of Japan on April 20, prompting tsunami warnings and emergency evacuations across parts of the country’s Pacific coastline, according to Japanese authorities.
The quake, with a preliminary magnitude of 7.5, occurred at about 4:53 p.m. local time off the coast of Sanriku at a depth of approximately 10 kilometers (6.2 miles), the Japan Meteorological Agency (JMA) stated in an official update issued at 5:08 p.m. local time.
The JMA issued tsunami warnings for multiple regions, including the Pacific coastlines of Hokkaido, Aomori, and Iwate prefectures. Advisories were also extended to Miyagi and Fukushima prefectures, reflecting concerns about widespread coastal impact.
In its April 20 bulletin, the agency warned that “there is a risk of damage from a tsunami,” urging residents in coastal and river areas to “immediately evacuate to higher ground or safe buildings.”
It cautioned that tsunamis can strike repeatedly and advised people not to leave safe areas until warnings are lifted.
The agency also reported seismic intensity levels reaching 5+ on Japan’s scale in parts of Aomori prefecture, with shaking felt across a wide area from Hokkaido to the Kinki region.
Long-period ground motion of magnitude 3 was observed in parts of Miyagi and Akita prefectures.
In an April 20 post on X, Japanese Prime Minister Sanae Takaichi said the government had activated crisis response systems immediately after the quake.
She noted that tsunami warnings had been issued for several coastal areas and urged residents to evacuate to higher ground or safer locations.
“[Officials are fully] committed to responses such as grasping the damage situation, emergency disaster measures including lifesaving and rescue, and providing timely and accurate information to the public,” Takaichi said.
Nuclear Plant Precautions
The earthquake also prompted safety measures at nuclear facilities. Tokyo Electric Power Co. said in an April 20 statement that there were no abnormalities detected in its main power systems following the quake.“At around 4:53 p.m. on April 20, 2026, an earthquake with a magnitude of 7.5 on the Richter scale struck off the coast of Sanriku, Japan,” the company stated. “As of now, there is no abnormality with our main power system.”
However, in response to tsunami advisories affecting Fukushima prefecture, evacuation orders were issued to workers at the Fukushima Daiichi and Fukushima Daini nuclear power stations.
Authorities warned that the risk of additional seismic activity remains elevated in the coming days. The JMA stated that, in past events, earthquakes of similar magnitude have been followed by additional strong quakes within about a week.
The agency cautioned that earthquakes with magnitudes of 5 or higher could occur, particularly within two to three days of the initial event. It also warned of increased risks of landslides and rockfalls in areas that experienced strong shaking.
“We are currently reviewing whether the conditions for issuing a warning about a subsequent earthquake off the coast of Hokkaido and Sanriku meet the criteria,” the agency said in its April 20 statement.
