Magnitude-7 earthquake shakes Japan, triggers tsunami concerns


Daily activities across portions of Japan were disrupted late Saturday afternoon when a 7-magnitude earthquake shook the country and triggered tsunami concerns.

According to the United States Geological Survey, the earthquake occurred at 6:09 p.m. The USGS pinpointed the epicenter of the quake to be located 16.7 miles east of Ishinomaki, Japan, at a depth of 33.5 miles.


When the earthquake first occurred, the initial USGS report placed the magnitude of the quake at a 7.2, but that magnitude was quickly adjusted to 7.

A tsunami advisory was in effect for portions of coastal Japan Saturday evening, according to the Japan Meteorological Agency. The entire coastline of the Miyagi prefecture, the area closest to the epicenter of the quake, was alerted to the possibility of a tsunami wave of up to 3.28 feet. These tsunami advisories were canceled by the JMA shortly before 8 p.m.

Evacuation orders that were in place for the Miyagi prefecture were also lifted with the cancellation of the tsunami advisory.

The National Weather Service’s Tsunami Warning System indicated that a Pacific-wide tsunami was not expected and that there were no immediate threats to Guam, Rotam, Tinian, Saipan, Hawaii or the Pacific coast of the United States.

Shaking as a result of the earthquake was felt in the capitol city of Tokyo by 6:10 p.m. Due to the quake, operations of the Tokaido Shinkansen rail network were suspended in Tokyo for a time on Saturday.

Operations at the Onagawa nuclear power plant were also suspended for a time while Tohoku Electric checked the plant for any irregularities following the quake.

Around 8 p.m., Japan’s Nuclear Regulation Authority reported that no abnormalities were found at the power plants across the region.

This map shows the epicenter of a 7.0 earthquake off the coast of Japan late Saturday afternoon, local time, and the areas estimated to have felt shaking. Photo courtesy of USGS

At least one injury has been attributed to the earthquake. One person was injured in Ishinomaki City in the Miyagi prefecture, according to a report from the local fire department. Partial power outages were reported across the Miyagi prefecture.

This earthquake comes just days after the 10-year anniversary of the infamous March 11, 2011, Japan earthquake and tsunami disaster. This 2011 quake, also known as the Great Sendai Earthquake or Great Tōhoku Earthquake, caused widespread damage to Japan and initiated a series of devastating tsunami waves. This quake also led to the nuclear disaster at the Fukushima Daiichi Power Plant.

An earthquake very similar in magnitude and location to Saturday’s quake occurred in February of this year. According to a spokesperson from the Japan Meteorological Agency, that February 2021 quake was considered to be an aftershock of the March 11, 2011, earthquake.

This is a developing story.