Japan earthquake live: Tsunami alert lifted after 6.9-magnitude tremor prompts evacuations along Pacific coast
Details on damage and injuries from the new quake weren’t immediately clear
Japan was struck by a new 6.9-magnitude earthquake on Friday morning, hitting a similar area of the Pacific coast to Monday night’s powerful 7.5-magnitude tremor.
The new quake off Aomori prefecture triggered a fresh tsunami advisory from the Japan Meteorological Agency, which warned of the potential for 1 metre tsunami waves along much of the Pacific coast of Hokkaido, Aomori, Iwate and Miyagi prefectures.
That advisory was lifted around two hours later, but a number of communities along the coast were evacuated.
The extent of damage or injuries from the new quake wasn’t immediately clear.
Japan had earlier warned of possible aftershocks following Monday’s 7.5-magnitude tremor. Monday night’s earthquake injured at least 51 people and triggered widespread tsunami warnings, with waves of up to 70cm reported in several coastal communities.
On Tuesday, Japan’s weather agency issued its highest-level warning that a megaquake – an earthquake of magnitude 8 or higher – could follow Monday’s powerful tremor. The notice, which remains in place until 16 December, was the first time this top-tier alert has been issued since the warning system was launched in 2022.
Unruptured Iwate fault raises alarm as expert warns heightened seismic activity possible in coming days
The Pacific coast is at risk because the recent quakes are occurring along a historically active offshore zone where major earthquakes tend to occur in sequence, an expert has said.
Monday’s 7.5 quake struck in the northern part of the same fault area that produced the deadly 7.9 quake in 1968.
Friday’s 6.9 magnitude earthquake hit a similar area of the Pacific coast to Monday night’s powerful 7.5-magnitude tremor.
The southern portion of that zone already ruptured in 1994 with a 7.6 quake, and another strong 6.9 quake struck just south of it in November this year.
Fumiaki Tomita, associate professor at the International Research Institute of Disaster Science of Japan’s Tohoku University, suggests that stress along the offshore fault system is shifting northward.
“Earthquakes with magnitudes of 8 could strike the area (if large-scale slips occur between the two plates),” he warned.
According to him, the northern area off Iwate is now the only segment of this seismic zone that has not released a large earthquake since 1968.
Because unruptured segments can accumulate strain, they are more likely to produce powerful quakes and tsunamis, he says.
More major earthquakes possible off Aomori, says Japanese research institute
A Tohoku University disaster science researcher has warned that more major earthquakes – potentially as strong as magnitude 7 or 8 – could follow Monday’s 7.5 quake off Aomori.
Fumiaki Tomita, associate professor at the International Research Institute of Disaster Science of Japan’s Tohoku University, has urged communities along the Pacific coast from Hokkaido to Chiba to stay alert for both strong shaking and possible tsunamis.
“Earthquakes with magnitudes of 8 could strike the area (if large-scale slips occur between the two plates),” he warned, according to The Japan Times.
The Japan Meteorological Agency’s megaquake advisory for a possible huge earthquake remains in effect until midnight Tuesday, but the expert said that people should remain prepared even after the advisory expires.
Bullet trains suspended due to outage
Bullet train services on the Tohoku Shinkansen Line were temporarily suspended today between Sendai in Miyagi Prefecture and Aomori due to power outages, JR East reported.
The disruption came in the wake of a magnitude 6.9 earthquake that struck off the coast of Aomori prefecture in northeastern Japan.
The Japanese weather agency said that today’s quake was too weak to trigger a new megaquake advisory but advised the public to stay vigilant.
A megaquake advisory, issued after Monday’s earthquake, remains in place until 11.59pm Monday.
No abnormalities at nuclear facilities, Japan’s nuclear regulation authority says
Tohoku Electric Power Company reports that the Higashidori nuclear power plant in Aomori Prefecture and the Onagawa plant in Miyagi Prefecture are operating normally, with no abnormalities detected, NHK Japan reported.
Tokyo Electric Power Company confirmed that Fukushima Daiichi and Daini nuclear plants are stable, with radiation monitoring posts showing no unusual readings after this morning’s 6.7-magnitude earthquake.
Japan’s Nuclear Regulation Authority added that there are “no immediate signs of abnormalities” at nuclear facilities in the region affected by the quake.
Low tide helped blunt the impact of Monday’s tsunami, expert says
The tsunami triggered by Monday night’s powerful 7.5-magnitude earthquake off Japan’s northeast coast could have caused significantly more damage if its largest wave had arrived at high tide, according to disaster researchers.
The biggest wave – a 70-centimetre surge recorded at Kuji port – reached the coast about 90 minutes after the first tsunami warning.
“It was lucky that the highest tsunami in the Monday quake came at low tide, which means that the tide level is 1.5 metres lower than at high tide,” Shunichi Koshimura, professor at Tohoku University’s International Research Institute of Disaster Science, told the local media.
He added that the timing reduced the risk of flooding. If the same wave had come at high tide, the impact could have been much more severe, he says.
Kuji port also recorded Japan’s highest tsunami following the 30 July Kamchatka earthquake, when a 141-centimetre wave struck the area.
Koshimura also warned that the strongest tsunami waves do not always arrive first. Monday’s peak wave was the fifth to hit Kuji.
“We have to be careful about the biggest wave, which may come late.”
Yet another tremor rocks Japan
An earthquake struck at around 7.05pm local time, with shaking felt across several prefectures, according to NERV – an app that provides real-time disaster prevention updates.
It said on X that the strongest tremors – rated intensity 4 on Japan’s seven-tier seismic scale – were recorded in northern and southern Ibaraki, southern Tochigi, southern Saitama and northwestern Chiba.
Milder shaking, rated intensity 3, was observed in parts of Fukushima’s Nakadori region, southern Gunma, northern Saitama and northeastern Chiba, among other areas.
This comes after this morning’s magnitude 6.9 earthquake off the coast of Aomori.
A few hours later, at about 12.21pm, a magnitude 5.7 tremor hit the same region, according to the Japanese weather agency’s website.
According to the USGS website, four tremors of magnitude 5.5, 4.7, 4.6 and 4.9 struck Japan’s Pacific coast after today’s 6.9 magnitude earthquake.
Unruptured Iwate fault raises alarm as expert warns heightened seismic activity possible in coming days
The Pacific coast is at risk because the recent quakes are occurring along a historically active offshore zone where major earthquakes tend to occur in sequence, an expert has said.
Monday’s 7.5 quake struck in the northern part of the same fault area that produced the deadly 7.9 quake in 1968.
Friday’s 6.9 magnitude earthquake hit a similar area of the Pacific coast to Monday night’s powerful 7.5-magnitude tremor.
The southern portion of that zone already ruptured in 1994 with a 7.6 quake, and another strong 6.9 quake struck just south of it in November this year.
Fumiaki Tomita, associate professor at the International Research Institute of Disaster Science of Japan’s Tohoku University, suggests that stress along the offshore fault system is shifting northward.
“Earthquakes with magnitudes of 8 could strike the area (if large-scale slips occur between the two plates),” he warned.
According to him, the northern area off Iwate is now the only segment of this seismic zone that has not released a large earthquake since 1968.
Because unruptured segments can accumulate strain, they are more likely to produce powerful quakes and tsunamis, he says.
More major earthquakes possible off Aomori, says Japanese research institute
A Tohoku University disaster science researcher has warned that more major earthquakes – potentially as strong as magnitude 7 or 8 – could follow Monday’s 7.5 quake off Aomori.
Fumiaki Tomita, associate professor at the International Research Institute of Disaster Science of Japan’s Tohoku University, has urged communities along the Pacific coast from Hokkaido to Chiba to stay alert for both strong shaking and possible tsunamis.
“Earthquakes with magnitudes of 8 could strike the area (if large-scale slips occur between the two plates),” he warned, according to The Japan Times.
The Japan Meteorological Agency’s megaquake advisory for a possible huge earthquake remains in effect until midnight Tuesday, but the expert said that people should remain prepared even after the advisory expires.
No abnormalities at nuclear facilities, Japan’s nuclear regulation authority says
Tohoku Electric Power Company reports that the Higashidori nuclear power plant in Aomori Prefecture and the Onagawa plant in Miyagi Prefecture are operating normally, with no abnormalities detected, NHK Japan reported.
Tokyo Electric Power Company confirmed that Fukushima Daiichi and Daini nuclear plants are stable, with radiation monitoring posts showing no unusual readings after this morning’s 6.7-magnitude earthquake.
Japan’s Nuclear Regulation Authority added that there are “no immediate signs of abnormalities” at nuclear facilities in the region affected by the quake.
Understanding Japan’s seismic activity and megaquake advisory
Japan sits at the junction of several tectonic plates, making it one of the most seismically active regions in the world. While earthquakes are common, some of the most powerful and dangerous ones originate from ocean trenches.
Monday’s magnitude-7.5 earthquake in northern Japan has brought attention back to the Japan Trench and the Chishima Trench.
A trench earthquake occurs along a deep crack in the ocean floor, called a trench, where one tectonic plate slides beneath another in a process known as subduction.
Over years or decades, stress builds as the plates get stuck.
When that stress is suddenly released, it can produce a powerful megathrust earthquake.
Because these earthquakes occur under the ocean, they often generate tsunamis, which can be extremely large and destructive.
The Japan Trench, off the east coast of Honshu, and the Chishima Trench, off northern Hokkaido and stretching toward the Kuril Islands, are key locations for these events.
These trenches have produced some of Japan’s most devastating earthquakes, including the 2011 Tohoku earthquake, a magnitude 9.0 megathrust quake that triggered massive tsunamis along the coast.
Historical patterns show that magnitude-7 or higher quakes in these regions can be followed by even larger earthquakes, according to the Japanese Meteorological Agency (JMA).
This is why Japan established a megaquake advisory system – a special alert to warn residents of northern Japan when the risk of a major trench-type earthquake and tsunami is elevated.
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