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Home » JMA Says Aichi Quake Not a Nankai Trough Precursor but Calls for Week of Vigilance

JMA Says Aichi Quake Not a Nankai Trough Precursor but Calls for Week of Vigilance

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JMA Says Aichi Quake Not a Nankai Trough Precursor but Calls for Week of Vigilance

TOKYO, November 9, 2026 — A magnitude 5.7 earthquake struck western Shizuoka Prefecture early Sunday, producing the strongest shaking recorded in neighboring Aichi Prefecture in 29 years and injuring at least 22 people across central Japan. The Japan Meteorological Agency (JMA) said the event does not indicate a change in the locked state of the Nankai Trough plates, though it warned of a high probability of strong aftershocks over the coming week.

Strongest Shaking in Aichi Since 1997

The quake occurred at 1:04 a.m. on November 8 at a depth of approximately 40 kilometers, according to the JMA. The U.S. Geological Survey recorded the magnitude slightly lower at 5.5. Seismic intensity of Upper 5 — a level where most people find it difficult to move and unsecured furniture may topple — was observed in Chita City, Aichi Prefecture. The agency said this marked the first Upper 5 reading in Aichi since 1997.

At least 22 people were injured across Aichi and Shizuoka prefectures, primarily from falls while evacuating, including down stairs, officials noted. Damage reports included shattered store windows, books fallen from shelves, and structural damage in Yamanashi, Hamamatsu, Kyoto, and Nara. No fatalities were reported, and no tsunami warning was issued.

Transport and Infrastructure Impact

Tokaido Shinkansen bullet trains operated at reduced speeds between Shizuoka and Nagoya as a precaution while railway operators inspected tracks for damage. Services were fully restored by noon, the company said. The central government established a liaison office at the Prime Minister’s Office Crisis Management Centre to coordinate the response.

No anomalies were detected at the Hamaoka nuclear power plant in Shizuoka Prefecture, which sits near the Nankai Trough zone, officials noted.

JMA Rules Out Immediate Megathrust Link

The earthquake occurred within the assumed focal region of the Nankai Trough, a subduction zone off Japan’s Pacific coast where scientists have long warned a megathrust earthquake could strike. However, JMA official Ayataka Ebita said the connection to such an event is believed to be low at this time. The agency stated the quake does not indicate any particular change in the locked state between the plates.

The Evaluation Committee on Earthquakes along the Nankai Trough convened on November 9 to conduct detailed analysis of the event, including the fault’s movement direction and the depth of the epicenter. The agency noted the quake did not meet the threshold for issuing “Nankai Trough Earthquake Extra Information,” which is triggered by observed anomalous phenomena.

Week of Vigilance Advised

Despite the low megathrust link, the JMA warned of a high possibility of another major earthquake reaching Upper 5 intensity over the next two to three days, urging caution for about a week. Residents in affected areas were advised to watch for mudslides, falling rocks, and the effects of rainfall. A separate magnitude 4.3 earthquake struck Kumamoto Prefecture at 10:53 a.m. on November 8, though the agency did not link the two events.

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Photo: Jose Antonio Gallego Vázquez / Unsplash (Unsplash License)

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