Powerful Earthquake Strikes Off Northern Japan, Prompting Tsunami Advisory

TOKYO – A significant earthquake with a preliminary magnitude of 6.8 struck off the coast of northeastern Japan on Sunday evening, jolting the region and prompting authorities to issue a tsunami advisory for coastal communities.

The quake, which hit at around 5 p.m. local time, was centered off the coast of Iwate Prefecture at a relatively shallow depth of 10 kilometers (6.2 miles), according to the Japan Meteorological Agency (JMA). The agency reported a shindo intensity of 4—a metric measuring ground motion—in parts of Iwate, indicating strongly felt shaking. A series of smaller aftershocks followed the initial temblor, keeping residents on edge.

Immediate Warnings and Precautionary Measures

In response to the seismic activity, the JMA immediately issued a tsunami advisory, warning of waves potentially reaching up to 1 meter (3 feet). While an advisory is less severe than a full-scale tsunami warning, authorities and public broadcaster NHK urgently advised residents to evacuate coastal areas and riversides.

“Please do not approach the coast, and leave the area immediately if you are there,” NHK announced in its continuous coverage. The broadcaster emphasized that tsunami waves can arrive repeatedly for hours and may grow in height.

Initial tsunami observations confirmed the arrival of the waves, with heights of around 20 centimeters (8 inches) reported in Kuji and smaller waves detected in several other ports along the Iwate coast. The advisory remained in effect for over an hour as officials monitored the situation.

Transport Disruptions and Infrastructure Checks

The quake caused temporary delays to bullet train services in the Tohoku region operated by JR East as crews conducted safety inspections. Kyodo News also reported some power outages in the affected area.

Crucially, there were no immediate reports of significant injuries or widespread structural damage. Officials also confirmed that no abnormalities were detected at nuclear power plants in the region, including the Fukushima Daiichi plant, which was devastated by a tsunami in 2011, and the nearby Onagawa plant.

A Nation on Alert in a Seismically Active Zone

The event served as a stark reminder of Japan’s vulnerability to natural disasters. Situated on the Pacific “Ring of Fire,” the country is one of the most earthquake-prone in the world. The memory of the March 11, 2011, magnitude 9.0 quake—which triggered a massive tsunami and the subsequent Fukushima nuclear disaster—remains fresh in the national consciousness.

Sunday’s quake, while far less powerful, triggered the well-rehearsed emergency response protocols that are a routine part of life in Japan. The differing magnitude readings—6.7 from the JMA and 6.8 from the U.S. Geological Survey—are common due to variations in measurement techniques. As the shaking subsided and the tsunami advisory was eventually lifted, the focus turned to assessing any minor damage and bracing for potential further aftershocks.

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