Aichi

A powerful earthquake struck central Japan early Sunday, shaking several prefectures, breaking shop windows and sending residents rushing out of buildings. At least 22 people were injured, according to Japanese media reports, as emergency authorities assessed the impact and warned residents to remain prepared for further seismic activity.

The Japan Meteorological Agency (JMA) estimated the earthquake's preliminary magnitude at 5.7, while the United States Geological Survey (USGS) recorded it at 5.5. The difference reflects separate measurement assessments by the two institutions.

The earthquake occurred at approximately 1:04 a.m. local time, with its epicentre in western Shizuoka Prefecture, at a depth of around 40 kilometres beneath the Earth's surface.

The strongest shaking was recorded in neighbouring Aichi Prefecture, where some locations experienced an upper-5 level on Japan's seismic intensity scale. The tremors were also felt across several other prefectures, including Gifu, Nagano, Yamanashi, Mie, Kyoto and Nara.

Shop windows shattered as residents fled buildings

The earthquake caused visible damage in several affected areas. Television footage showed broken shop windows, pieces of glass scattered across streets and merchandise thrown from shelves.

A bookstore was particularly affected, with large numbers of books falling from shelves and covering the floor. The shaking also caused people to rush out of buildings, creating confusion during the early morning hours.

At least 22 people were reported injured, although the full extent of the damage and the number of people requiring medical treatment were still being assessed.

Some injuries occurred when people fell while attempting to escape buildings. Such incidents are common during sudden earthquakes, particularly when residents try to move quickly through staircases or crowded indoor spaces.

Authorities and emergency personnel continued monitoring the affected locations for structural damage and other hazards.

Aichi and Shizuoka experience strongest shaking

The earthquake was centred in western Shizuoka Prefecture, but the most intense shaking was observed in parts of Aichi.

The city of Chita in Aichi recorded an upper-5 intensity level on Japan's seven-level seismic intensity scale. Other areas, including parts of Seto and Hamamatsu, also experienced strong shaking.

The tremors were felt across a wider geographical area, reaching parts of central and western Japan. However, Tokyo was not significantly affected, according to initial reports.

Japan uses a seismic intensity system that measures how strongly an earthquake is experienced at specific locations. It differs from magnitude, which measures the overall size of an earthquake.

An earthquake with a magnitude of 5.7 can therefore produce different levels of shaking depending on the distance from its epicentre, local geological conditions and the depth of the seismic event.

Meteorological agency warns of possible further earthquakes

Following the earthquake, the Japan Meteorological Agency advised residents to remain alert for additional strong tremors over the coming week, particularly during the next two to three days.

Officials also warned about secondary dangers such as landslides and falling rocks, especially if rainfall affects areas where the ground has already been disturbed.

The agency urged residents to review their emergency preparations and remain aware of official announcements.

Japan is located along the Pacific Ring of Fire, one of the world's most seismically active regions. The country experiences frequent earthquakes because several tectonic plates interact beneath and around the Japanese archipelago.

Although buildings and infrastructure are designed with earthquake resistance in mind, strong tremors can still cause injuries, damage property and disrupt transport services.

No immediate change detected at Nankai Trough

The latest earthquake also drew attention to the Nankai Trough, an offshore geological zone where scientists have warned that a major earthquake could occur in the future.

The Nankai Trough lies along the Pacific coast of southwestern Japan. It is associated with the movement of tectonic plates beneath the region and has produced major earthquakes in the past.

However, a JMA official said that no apparent change had been detected in the Nankai Trough plate following Sunday's earthquake.

This does not mean that the possibility of a future major earthquake has disappeared. Scientists have long warned that the region remains capable of producing a powerful seismic event.

Authorities have repeatedly encouraged communities, businesses and households to prepare for such emergencies through evacuation planning, emergency supplies and public safety education.

Bullet train services operate at reduced speeds

The earthquake also affected transportation operations in parts of central Japan.

Shinkansen bullet trains operating through affected areas were running at reduced speeds as a precautionary measure. Railway operators generally introduce such restrictions after significant seismic activity to allow safety checks and reduce potential risks.

Earthquakes can damage railway tracks, bridges and other transport infrastructure even when visible damage is not immediately apparent. Speed restrictions help operators assess conditions before restoring normal services.

Passengers were advised to follow railway announcements and expect possible delays while safety procedures continued.

No major disruption to the wider national transport network was immediately reported in the initial accounts.

Japan continues to strengthen earthquake preparedness

Sunday's earthquake once again highlighted the importance of emergency preparedness in Japan.

Authorities regularly advise residents to keep drinking water, food, batteries, flashlights and essential medicines available. People are also encouraged to identify safe places inside their homes and workplaces, including areas where they can protect themselves during strong shaking.

Residents are generally advised to stay away from windows, avoid elevators during earthquakes and protect their heads and bodies under sturdy furniture when possible.

After the shaking stops, damaged buildings, broken glass, unstable structures and possible aftershocks can create additional risks.

For now, emergency authorities are continuing to assess the consequences of the earthquake, while residents in affected prefectures remain on alert.

With at least 22 people injured and damage reported to shops and other properties, the incident serves as another reminder of Japan's continuing exposure to seismic hazards. Officials have urged the public to remain cautious and rely on verified information as monitoring continues.