Magnitude 3.9 Earthquake Strikes Aichi-ken, Japan

Moderate Tremor in Aichi-ken

A moderate earthquake with a magnitude of 3.9 struck near Konan, Aichi-ken, Japan, on Sunday, January 4, 2026, at 6:16 pm local time (GMT +9). The seismic event occurred at a moderately shallow depth of 40 kilometers.

Reporting Agencies and Magnitude Assessment

Initial reports from the European-Mediterranean Seismological Centre (EMSC) and the citizen-seismograph network RaspberryShake indicated a magnitude of 3.9. However, Japan's National Research Institute for Earth Science and Disaster Resilience (NIED) later issued a report listing the earthquake as a magnitude 4.0 event. Seismologists often review data to refine exact magnitude, epicenter, and depth in the hours following an earthquake.

Impact and Felt Reports Across the Region

The shallow depth of the earthquake meant it was felt by many residents near the epicenter. User reports suggested the shaking was perceptible up to approximately 100–250 kilometers away, with some isolated reports from as far as 263 kilometers. Several cities and towns in the region experienced weak shaking, including:

• Ginan (pop. 25,900), located 2 km from the epicenter
• Gifu (pop. 402,600), 4 km away
• Kakamigahara (pop. 144,500), 6 km away
• Konan (pop. 98,300), 10 km away
• Ichinomiya (pop. 380,100), 11 km away
• Inuyama (pop. 74,000), 13 km away
• Inazawa (pop. 134,800), 17 km away
• Komaki (pop. 148,900), 17 km away
• Nagoya (pop. 2,332,200), 26 km away, where residents likely experienced 'weak shaking'

Japan's Seismic Landscape and Monitoring

Japan is situated in one of the world's most seismically active zones, making earthquakes a frequent occurrence. The Japan Meteorological Agency (JMA) continuously monitors seismic activity across the country. The JMA utilizes a unique seismic intensity scale, known as Shindo, which ranges from 0 to 7, to describe the intensity of local ground shaking at various observation points.

No Immediate Damage Reported

As of the latest updates, there have been no immediate reports of significant damage or casualties resulting from this moderate earthquake. Authorities continue to monitor the situation, and further details may emerge as more comprehensive data becomes available.