M4.4 Earthquake 78 km NNW of Uken, Japan — September 18, 2026
2026-09-18 16:27:16 UTC (2026-09-18) · approx. 1:27 AM UTC+9 local
On September 18, 2026 at 16:27 UTC, a magnitude 4.4 shallow crustal earthquake struck 78 km NNW of Uken, Japan, at a depth of 10.0 km and coordinates 28.9552°, 128.9327°.
Physical scale: An earthquake of magnitude 4.4 releases seismic energy equivalent to roughly 60 metric tons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 655 m — 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 5.1 mainshock that occurred 20 days ago 88 km NNW of Uken, 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.
Earthquake Details
128.9327°E
Technical Information
Common Questions
How strong was the magnitude 4.4 earthquake near Uken, Japan?
The magnitude 4.4 earthquake that struck 78 km NNW of Uken, Japan on September 18, 2026 at 16:27 UTC had a depth of 10.0 km. For context, this was a light earthquake commonly felt near the epicenter.
Were there aftershocks?
Aftershock activity is monitored continuously by the USGS. Aftershock sequences from magnitude 4.4 earthquakes can continue for several days and gradually diminish over time.
Is this the same earthquake as the M5.1 one earlier?
No. This magnitude 4.4 earthquake is an aftershock of the larger magnitude 5.1 mainshock that occurred earlier 88 km NNW of Uken, Japan. Aftershocks are smaller earthquakes triggered by stress changes from the mainshock.
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Understanding This Data
Magnitude 4.4 earthquakes are often felt but rarely cause damage.
Authoritative source: USGS event page (event ID: us7000tir5). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2026, September 18, 2026). M4.4 Earthquake 78 km NNW of Uken, Japan — September 18, 2026. Retrieved September 25, 2026 from https://www.earthquaketracker.org/earthquakes/event/us7000tir5/