M4.0 Earthquake 38 km ENE of Noda, Japan — October 7, 2023
2023-10-07 21:57:55 UTC (2023-10-07) · approx. 6:57 AM UTC+9 local
On October 7, 2023 at 21:57 UTC, a magnitude 4.0 shallow crustal earthquake struck 38 km ENE of Noda, Japan, at a depth of 56.5 km and coordinates 40.2382°, 142.2377°.
Physical scale: An earthquake of magnitude 4.0 releases seismic energy equivalent to roughly 15 metric tons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 347 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 5.5 mainshock that occurred 15 days ago 47 km ENE of Noda, Japan. Since the mainshock, the USGS has recorded 3 aftershocks in this area. Aftershock activity is expected to continue for days to weeks as stresses on surrounding faults redistribute.
Earthquake Details
142.2377°E
Technical Information
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Common Questions
How strong was the magnitude 4.0 earthquake near Noda, Japan?
The magnitude 4.0 earthquake that struck 38 km ENE of Noda, Japan on October 7, 2023 at 21:57 UTC had a depth of 56.5 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 4.0 earthquakes can continue for several days and gradually diminish over time.
Is this the same earthquake as the M5.5 one earlier?
No. This magnitude 4.0 earthquake is an aftershock of the larger magnitude 5.5 mainshock that occurred earlier 47 km ENE of Noda, Japan. Aftershocks are smaller earthquakes triggered by stress changes from the mainshock.
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Understanding This Data
Magnitude 4.0 earthquakes are often felt but rarely cause damage.
Authoritative source: USGS event page (event ID: us6000leux). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2023, October 7, 2023). M4.0 Earthquake 38 km ENE of Noda, Japan — October 7, 2023. Retrieved December 14, 2023 from https://www.earthquaketracker.org/earthquakes/event/us6000leux/