ALERT: Japan reduces tsunami warning after 7.7 magnitude earthquake that shook the northeast coast
In a major development, the following story has emerged from the international scene.
Being a country located in one of the largest seismic zones in the world and with the sad experience of past tragedies, Japan has one of the most advanced warning and prevention systems in the world. This mechanism was activated again this Monday, April 20, when a powerful earthquake of magnitude 7.7 was recorded in the waters of the Pacific Ocean, off the coast of Sanriku, in the prefecture of Iwate, at the northern end of the island of Honshu, the largest in the country. The earthquake occurred around 16:53 local time (07:53 GMT), at a depth of about 10 kilometers, as confirmed by the Japan Meteorological Agency (JMA), an organization that subsequently issued tsunami warnings for coastal areas from Hokkaido to Fukushima prefecture, with waves that could reach three meters. Between one and two hours after the earthquake, waves of up to 80 centimeters high were detected in the port of Kuji, in Iwate prefecture, and another surge of about 40 centimeters in another port in the same prefecture. While late at night the alert had been lowered to a warning, the Pacific Tsunami Warning Center, based in the United States, indicated that the threat “has already passed.” To display this content from X (Twitter), you must allow audience measurement and advertising cookies. Accept Manage my options “In the affected regions, please evacuate to higher and safer places, such as hills or evacuation buildings, pay close attention to the information about the tsunami and do not leave the safe place until the alert is lifted,” Prime Minister Sanae Takaichi asked on her X account, replicating the warnings of the meteorological service. The head of the Japanese government also indicated that a “crisis management center” was established to “collect information on the damage situation” and “implement emergency measures to save lives,” among other responses. Mild alert for possible ‘megaquake’ The earthquake led authorities to urge residents to stay away from coastal areas where tsunami waves of up to 3 meters were expected. Two hours after the earthquake, tsunami waves of up to 80 cm were detected. However, the alert was later reduced to a tsunami warning. The Fire and Disaster Management Agency assured that no serious damage has been reported and that one person in Aomori (north of Iwate) was injured in a fall. This body added that Iwate and three other prefectures in northern Japan issued non-binding evacuation notices for more than 128,000 people. Likewise, the high-speed train service connecting Tokyo with Shin-Aomori was partially interrupted, some highways were closed and the strong tremor was felt in some tall buildings in Tokyo. On the local channel NHK, the usual programming was interrupted to make way for a special broadcast with cameras installed in the affected areas, maps of the areas on alert and information on the rise in sea level at different points. A television screen shows the tsunami warning issued by the Japan Meteorological Agency, following an earthquake with a preliminary magnitude of 7.4 off the northeast coast of the country, in Tokyo, Japan, on April 20, 2026. © Issei Kato / Reuters Many people could be seen driving to high places on their screens. A resident of Tomakomai, Hokkaido, arrived at a park on top of a hill after picking up his son from an educational institution and told the aforementioned media that he would remain there until the alert was lifted. On the other hand, the Cabinet Office and the Japan Meteorological Agency slightly raised the alert regarding the probability of a ‘megaearthquake’ occurring on the country’s northern coast during the next week. Typically, the chance of an earthquake of magnitude 8 or greater shaking the Japan and Kuril Trenches in the Pacific is approximately 0.1%, but in the wake of Monday’s powerful earthquake, that estimate rises to 1% over the next seven days. Authorities clarified that this does not constitute a seismic prediction, but urged residents to reinforce their preparation with measures such as stocking up on emergency food and preparing a backpack with all the essentials, without abandoning their normal lives. Japan, a country vulnerable to seismic movements This is the third time that the JMA issues a “megaearthquake” warning. The most recent was in December 2025, after a magnitude 7.5 earthquake struck the northern coast on December 8, injuring more than 40 people and causing waves of up to 70 centimeters. The first alert of this type, meanwhile, occurred in 2024, about a possible phenomenon of this type along the Nankai Trench, an 800-kilometer area where the oceanic tectonic plate of the Philippine Sea is slowly sliding beneath the continental plate on which Japan sits, so the Japanese government estimates that an earthquake and subsequent tsunami there could cause the death of up to 298,000 people and damage of up to 2,000. million dollars. Although at that time the warning was lifted after a week without any unusual movements, the alert alone triggered a rush of panic buying of basic products such as rice and led tourists to cancel their hotel reservations. And Japan is one of the countries with the highest seismic activity in the world, because it is located on four important tectonic plates along the western edge of the so-called ‘Ring of Fire’ of the Pacific. This long-exposure image shows a damaged house (front) with the facilities of Tokyo Electric Power Company Holdings’ (TEPCO) Fukushima Daiichi nuclear power plant (behind) seen from the Ukedo fishing port in Namie, Fukushima prefecture, on August 20, 2023. © AFP – Philip Fong The archipelago of 125 million inhabitants sees about 1,500 earthquakes a year –that is, an average of one every five minutes–, which represents around 18 percent of the world’s earthquakes. Although the vast majority are slight and the country has developed structures resistant to telluric movements, the damage can vary depending on the location of the phenomenon and its depth. In that nation, the memory of the 9.0 magnitude earthquake and the subsequent tsunami of March 11, 2011, which devastated parts of northern Japan, caused more than 22,000 deaths and forced almost half a million people to abandon their homes, is still very present. That earthquake also caused the Fukushima nuclear disaster, which led to the flight of some 160,000 people and whose consequences persist. Currently, some 26,000 residents have not returned to their homes, either because they have relocated to other locations, their hometowns remain restricted areas, or concerns remain about radiation levels. Faced with the fears revived by this Monday’s earthquake, the International Atomic Energy Organization (IAEA) reported that no anomalies have been observed in Japan’s nuclear facilities, while the Nuclear Regulatory Authority also did not record changes or damage, although there are no nuclear power plants in operation in the affected area. With Reuters, AP and AFP
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Source: This article was originally published in another language by France 24 – Noticias y actualidad internacional en vivo and has been translated and adapted for our global English-speaking audience. Read the original article here.