Japan Issues Warning After 7.7-Magnitude Quake Strikes North
On Monday, April 20, 2026, a powerful 7.7-magnitude earthquake struck in the Pacific waters off northern Iwate Prefecture, Japan, prompting a tsunami warning and a special advisory from the Japan Meteorological Agency (JMA) about an increased risk of stronger quakes.
The quake occurred at 4:53 p.m. Local time (3:53 p.m. Singapore time) and was felt as far away as Tokyo, where it shook large buildings hundreds of kilometres from the epicentre. The JMA initially estimated the magnitude at 7.4 before revising it upward to 7.7.
Following the main shock, the JMA issued a special advisory warning that “the likelihood of a fresh, huge earthquake occurring is relatively higher than during normal times.” The agency emphasized that while the probability remains low, there is a possibility of another major earthquake of magnitude 8.0 or stronger, urging residents to review their earthquake preparedness measures.
Around 40 minutes after the quake, an 80-centimetre tsunami wave was recorded at Kuji Port in Iwate Prefecture. Smaller tsunami waves were also observed at other coastal locations: 40 centimetres at Miyako Port in Iwate and Urakawa in Hokkaido, 30 centimetres at Hachinohe Port in Aomori, and 20 centimetres at Erimo and Ayukawa Port in Miyagi Prefecture.
Local authorities in the affected region issued non-compulsory evacuation directives to more than 182,000 residents, according to the Fire and Disaster Management Agency. No immediate reports of serious injuries or significant damage were confirmed by Chief Cabinet Secretary Minoru Kihara at a news conference, and footage from NHK showed no clearly visible damage around several ports in Iwate.
Officials cautioned that aftershocks could continue over the coming week, particularly within the next two to three days, potentially causing even stronger shaking. Japan’s location on the seismically active Pacific “Ring of Fire” makes it prone to such events, as demonstrated by the devastating 9.0-magnitude quake and tsunami in 2011.
The JMA continues to monitor seismic activity and provides earthquake early warnings to help mitigate disaster damage. Residents are advised to stay informed through official channels and follow safety guidelines during aftershock sequences.