M4.1 Earthquake 83 km SW of Yonakuni, Japan — September 18, 2024
2024-09-18 23:04:07 UTC (2024-09-18) · approx. 7:04 AM UTC+8 local
On September 18, 2024 at 23:04 UTC, a magnitude 4.1 shallow crustal earthquake struck 83 km SW of Yonakuni, Japan, at a depth of 20.4 km and coordinates 23.9088°, 122.4532°.
Physical scale: An earthquake of magnitude 4.1 releases seismic energy equivalent to roughly 21 metric tons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 406 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 5.6 mainshock that occurred 12 days ago 74 km S of Yonakuni, 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
122.4532°E
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Common Questions
How strong was the magnitude 4.1 earthquake near Yonakuni, Japan?
The magnitude 4.1 earthquake that struck 83 km SW of Yonakuni, Japan on September 18, 2024 at 23:04 UTC had a depth of 20.4 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 4.1 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 4.1 earthquake is an aftershock of the larger magnitude 5.6 mainshock that occurred earlier 74 km S of Yonakuni, Japan. Aftershocks are smaller earthquakes triggered by stress changes from the mainshock.
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Understanding This Data
Magnitude 4.1 earthquakes are often felt but rarely cause damage.
Authoritative source: USGS event page (event ID: us6000ntbf). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2024, September 18, 2024). M4.1 Earthquake 83 km SW of Yonakuni, Japan — September 18, 2024. Retrieved November 23, 2024 from https://www.earthquaketracker.org/earthquakes/event/us6000ntbf/