Earthquake now in Ibaraki causes tremors with magnitude 4.3 and scares residents in Japan Por Luís Henrique Costa
6 min de leitura
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A magnitude 4.3 earthquake struck southern Ibaraki, Japan, on the evening of September 5, 2025, around 9 p.m., causing tremors of intensity 4 in cities like Shimotsuke, Tochigi Prefecture, and intensity 3 in areas such as Koga and Joso in Ibaraki, as well as Utsunomiya, Saitama, and Gunma. According to the Japan Meteorological Agency, the epicenter was located at a depth of 50 km, and no tsunami warning was issued. So far, Shimotsuke firefighters reported no damages or injuries, though residents felt a significant impact, described as a mix of vertical and horizontal shaking. The event reignites concerns about seismic activity in one of the world’s most earthquake-prone regions.
Shimotsuke residents reported an initial scare, but daily life was not heavily disrupted. A local firefighter described the tremor as “a vertical jolt followed by a few seconds of lateral shaking, with no objects falling.” The absence of material damage was confirmed in nearby cities, but the frequency of tremors in the region keeps authorities on alert.
- Seismic intensity: Shimotsuke recorded intensity 4, the highest of the event.
- Affected areas: Ibaraki, Gunma, Saitama, and parts of southern Tohoku felt minor tremors.
- No tsunami risk: The epicenter’s depth minimized additional risks.
- Ongoing monitoring: The Japan Meteorological Agency continues to track possible aftershocks.
Intensity and distribution of tremors
The earthquake, centered in southern Ibaraki, was felt across a wide area of the Kantō region and parts of southern Tohoku. The seismic intensity, measured on Japan’s scale (1 to 7), reached level 4 in Shimotsuke, indicating noticeable tremors capable of startling residents and moving light objects. In cities like Koga, Joso, Utsunomiya, Tochigi, Tatebayashi, and Saitama, the intensity was 3, sufficient to cause concern but with Twisted or without significant structural damage.
Tremors of intensity 2 and 1 were recorded in more distant areas, such as Yamanashi and Shizuoka, showing the wide reach of the seismic waves. The 50 km depth of the epicenter helped dissipate energy, reducing the potential for severe damage. The Japan Meteorological Agency noted that the event is within the region’s expected patterns but emphasized the importance of preparedness for potential aftershocks.
Earthquake characteristics
The magnitude 4.3 quake was classified as moderate, but its epicenter near densely populated urban areas heightened its significance. The 50 km depth is considered intermediate, explaining the lack of major damage. Compared to more intense events, like the 2011 Tohoku magnitude 9 earthquake, this was far less destructive but serves as a reminder of Japan’s constant tectonic activity.
- Magnitude: 4.3 on the Richter scale, considered moderate.
- Depth: 50 km, dispersing seismic energy.
- Epicenter: Southern Ibaraki, near urban areas of Kantō.
- Japanese seismic scale: Maximum intensity 4 in Shimotsuke.
Public and official response
Residents of Shimotsuke and nearby cities reported surprise at the tremor, especially as it occurred in the early evening when many were at home. “It was a quick scare; the house shook for a few seconds,” said a Utsunomiya resident. Authorities responded swiftly, with statements from the Meteorological Agency and firefighters calming the public. No evacuations or tsunami alerts were necessary, but residents were advised to stay vigilant for potential aftershocks.
Shimotsuke firefighters, monitoring the situation immediately after the event, confirmed no emergency calls by 9:10 p.m. Local infrastructure, including roads and buildings, showed no visible damage. The Japan Meteorological Agency noted that the Kantō region lies near several tectonic faults, making such events relatively common but requiring constant vigilance.
Japan’s seismic context
Japan sits on the Pacific Ring of Fire, one of the most seismically active zones in the world, accounting for about 80% of global earthquakes. The Kantō region, including Tokyo and nearby areas, is particularly vulnerable due to its proximity to active faults like the Sagami Trough. Events like the September 5 earthquake highlight the importance of early warning systems and earthquake-resistant infrastructure, implemented by the Japanese government in recent decades.
While the magnitude 4.3 quake caused no damage, it comes amid heightened alertness in Japan. Recent reports indicate an 80% chance of a magnitude 8 to 9 megathrust earthquake in the Nankai Trough within decades, potentially causing devastating impacts. These concerns keep the public and authorities on high alert.
- Ring of Fire: A seismic zone encompassing Japan and other Pacific regions.
- Sagami Trough: An active fault near Kantō.
- Warning systems: Advanced technology for early tremor detection.
- Preparedness: Buildings and infrastructure designed to withstand quakes.
Prevention and safety measures
The Japan Meteorological Agency issued recommendations for residents to review emergency plans and keep survival kits updated. In urban areas like Kantō, where population density is high, earthquake preparedness is routine. Schools, businesses, and homes frequently conduct evacuation drills, and buildings are equipped with anti-seismic technologies, such as dampers and flexible foundations.
Post-quake, local authorities reiterated the importance of securing furniture and checking emergency exits. Residents were urged to stay calm during potential aftershocks and follow official updates. The lack of damage in this event highlights the effectiveness of preventive measures, but experts warn that stronger quakes require heightened caution.
Regional earthquake history
The Kantō region has a history of significant seismic events. The Great Kantō Earthquake of 1923, with a magnitude of 7.9, caused thousands of deaths and widespread destruction in Tokyo. More recently, the 2011 Tohoku earthquake, magnitude 9, triggered a devastating tsunami, underscoring the need for ongoing preparedness. The September 5 event, though minor, serves as a reminder of the region’s vulnerability.
- Great Kantō Earthquake (1923): Magnitude 7.9, major impact on Tokyo.
- Tohoku Earthquake (2011): Magnitude 9, followed by a tsunami and nuclear crisis.
- Seismic frequency: Kantō experiences dozens of noticeable quakes annually.
- Prevention advances: Early warning systems have saved lives in recent events.
Monitoring and future outlook
The Japan Meteorological Agency operates an advanced seismic monitoring system with seismographs nationwide. Data from the September 5 quake will refine prediction models and assess aftershock risks. While the event caused no damage, it underscores the need for continued investment in research and infrastructure.
The Kantō population, accustomed to tremors, showed resilience, but the potential for stronger quakes keeps the issue prominent. Authorities continue to update seismic risk maps and promote awareness campaigns, ensuring Japan remains prepared for its geological reality.
