M4.3 Earthquake 7 km WNW of Ichihara, Japan — November 13, 2025
2025-11-13 21:36:20 UTC (2025-11-13) · approx. 6:36 AM UTC+9 local
On November 13, 2025 at 21:36 UTC, a magnitude 4.3 intermediate depth earthquake struck 7 km WNW of Ichihara, Japan, at a depth of 97.4 km and coordinates 35.5524°, 140.0125°.
Physical scale: An earthquake of magnitude 4.3 releases seismic energy equivalent to roughly 43 metric tons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 558 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 5.8 mainshock that occurred 19 days ago 3 km SE of Yokoshiba, Japan. Since the mainshock, the USGS has recorded 0 aftershocks in this area. Aftershock activity is expected to continue for days to weeks as stresses on surrounding faults redistribute.
Earthquake Details
140.0125°E
Technical Information
Common Questions
How strong was the magnitude 4.3 earthquake near Ichihara, Japan?
The magnitude 4.3 earthquake that struck 7 km WNW of Ichihara, Japan on November 13, 2025 at 21:36 UTC had a depth of 97.4 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 4.3 earthquakes can continue for several days and gradually diminish over time.
Is this the same earthquake as the M5.8 one earlier?
No. This magnitude 4.3 earthquake is an aftershock of the larger magnitude 5.8 mainshock that occurred earlier 3 km SE of Yokoshiba, Japan. Aftershocks are smaller earthquakes triggered by stress changes from the mainshock.
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Understanding This Data
Magnitude 4.3 earthquakes are often felt but rarely cause damage.
Authoritative source: USGS event page (event ID: us7000rf34). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2025, November 13, 2025). M4.3 Earthquake 7 km WNW of Ichihara, Japan — November 13, 2025. Retrieved February 10, 2026 from https://www.earthquaketracker.org/earthquakes/event/us7000rf34/