M4.9 Earthquake 14 km NNE of Tsunagi, Japan — July 28, 2026
2026-07-28 08:18:54 UTC (1 hour ago) · approx. 5:18 PM UTC+9 local
Aftershock of the M5.6 mainshock.
On July 28, 2026 at 08:18 UTC, a magnitude 4.9 shallow crustal earthquake struck 14 km NNE of Tsunagi, Japan, at a depth of 10.0 km and coordinates 32.3585°, 130.5429°. This earthquake was detected by 57 seismic stations with good location accuracy and was assigned a USGS significance rating of 369, placing it among routine seismic activity.
Physical scale: An earthquake of magnitude 4.9 releases seismic energy equivalent to roughly 338 metric tons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 1.4 km — a useful intuition for the size of the slip patch on the fault.
This earthquake is part of an ongoing aftershock sequence following the magnitude 5.6 mainshock that occurred 1 hour ago 16 km NE of Tsunagi, Japan. Since the mainshock, the USGS has recorded 1 aftershocks in this area. Aftershock activity is expected to continue for days to weeks as stresses on surrounding faults redistribute.
The epicenter is located in Japan, a region characterized by the intersection of four tectonic plates — Pacific, Philippine Sea, Eurasian, and North American — creating multiple subduction zones. The nearest mapped fault system is the Japan Trench. View all earthquakes in Japan.
Learn more: Magnitude scale · Aftershock sequences
Earthquake Details
130.5429°E
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Common Questions
How strong was the magnitude 4.9 earthquake near Tsunagi, Japan?
The magnitude 4.9 earthquake that struck 14 km NNE of Tsunagi, Japan on July 28, 2026 at 08:18 UTC had a depth of 10.0 km. For context, this was a light earthquake commonly felt near the epicenter.
Where did the earthquake occur?
The earthquake epicenter was located at 32.3585°, 130.5429°, which is 14 km NNE of Tsunagi, Japan. View all earthquakes in Japan.
Were there aftershocks?
Aftershock activity is monitored continuously by the USGS. Aftershock sequences from magnitude 4.9 earthquakes can continue for several days and gradually diminish over time.
Is this the same earthquake as the M5.6 one earlier?
No. This magnitude 4.9 earthquake is an aftershock of the larger magnitude 5.6 mainshock that occurred earlier 16 km NE of Tsunagi, Japan. Aftershocks are smaller earthquakes triggered by stress changes from the mainshock.
Has Japan had earthquakes this big before?
The largest recorded earthquake in Japan was the M9.1 Tohoku earthquake of March 11, 2011. Today's magnitude 4.9 event is significantly smaller than that historical record.
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Authoritative source: USGS event page (event ID: us6000tgbn). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2026, July 28, 2026). M4.9 Earthquake 14 km NNE of Tsunagi, Japan — July 28, 2026. Retrieved July 28, 2026 from https://www.earthquaketracker.org/earthquakes/event/us6000tgbn/