At least 10 people were injured after a?magnitude 7.2 earthquake hit northern Japan on Thursday morning, registering a rare upper 6 on the Japanese seismic intensity scale of 7 in the town of Hashikami, Aomori Prefecture. No tsunami warning has been issued.
A mild quake was also felt in Tokyo.
The Japan Meteorological Agency said the epicenter was 44 kilometers deep off the coast of Iwate Prefecture. The city of Hachinohe in Aomori Prefecture registered a lower 6 while some cities in Iwate Prefecture registered an upper 5.
An intensity of?upper 6 is when people can only crawl and are unable to walk during an earthquake. Unsecured furniture will topple over, according to the JMA.
The Tohoku Shinkansen line halted operations earlier in the day, but services were resumed in the afternoon.?Numerous train lines in Iwate and Aomori prefectures have been suspended due to the quake, with no indication as to when they will resume.
The Prime Minister¡¯s Office has set up a task force over the quake.
Speaking to reporters, Prime Minister Sanae Takaichi said that there was ¡°no tsunami concern¡± and asked residents of the affected areas ¡°to remain vigilant for the possibility of another earthquake of similar magnitude.¡±
In a news conference Thursday morning, JMA officials warned those in areas most affected by the quake, particularly those living near the Japan Trench and Kuril Trench, to be on alert for future earthquakes for up to a week. Following a large quake, there is?a 10-20% chance that another major quake can occur in the same area, especially in the following two to three days.
According to Aomori Prefecture officials, nine people have been injured as a result of the quake, while in Iwate Prefecture, a woman in her 90s sustained a minor injury after she fell. There have been no reports of damages to nuclear power facilities in the area, Chief Cabinet Secretary Minoru Kihara told reporters.
Meanwhile, Defense Minister Shinjiro Koizumi ordered the Self-Defense Forces to conduct aerial intelligence-gathering operations in the quake-hit areas.
Northern Japan has been experiencing quakes in the past few months.
In May, a magnitude 6.3 earthquake, measuring a lower 5 on Japan¡¯s seismic intensity scale, struck the Tohoku region, while in April, a magnitude 7.7 quake struck the same area, causing authorities to issue a special advisory to be on alert for a larger quake.?
In Thursday¡¯s briefing, Ayataka Ebita, head of the agency¡¯s earthquake and tsunami monitoring division, said that the area is more prone to earthquakes, and that major quakes of magnitude 7 or above typically occur there every 10 to 20 years.
The government¡¯s headquarters for earthquake research said earlier this month that multiple quakes have been occurring in the area following a magnitude 7.7 quake on Nov. 4. The headquarters have stated they believe that this is due to post-seismic deformation in Iwate Prefecture. The area is the highest risk zone for a potential megathrust quake, according to the headquarters.
¡°Since the April quake, slow slip has been occurring after the large quake, a phenomenon known as afterslip,¡± said Fumiaki Tomita, a geodesy expert at Tohoku University. ¡°Thursday¡¯s quake occurred near this afterslip area. It¡¯s possible that the afterslip placed stress on this area, causing the quake.¡± However, this has not?yet been verified, he stressed.
The source of a 1994 offshore Sanriku earthquake, which had a magnitude of 7.6, lies on a shallower plate boundary than the source of this quake, Tomita said.?
¡°Due to this earthquake, as well as the afterslip and other slow slip events occurring in the surrounding area, one possible scenario is that an earthquake of a similar scale to the 1994 quake, or an even larger magnitude 8-class earthquake, could occur,¡± he added.
¡°Current science cannot say exactly when such large-scale earthquakes will happen. However, it¡¯s important to stay prepared in case one does occur.¡±
The government¡¯s headquarters for earthquake research?asserts that an analysis of repeat quakes in the surrounding area suggests that a seismic slip is ongoing. When asked about this by reporters in Thursday¡¯s briefing, JMA officials declined to comment.
More information:
An explanation of shindo, Japan¡¯s earthquake intensity scale
A guide to what to do before, during and after an earthquake
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