M4.3 Earthquake 31 km ENE of Iwaizumi, Japan — May 9, 2023
2023-05-09 18:02:54 UTC (2023-05-09) · approx. 3:02 AM UTC+9 local
On May 9, 2023 at 18:02 UTC, a magnitude 4.3 shallow crustal earthquake struck 31 km ENE of Iwaizumi, Japan, at a depth of 52.5 km and coordinates 39.9598°, 142.1384°.
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 5.5 mainshock that occurred 22 days ago 47 km ENE of Noda, 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.
Did You Feel It? — community-reported shaking
Aggregated felt-report intensity from 1 citizen response to the USGS Did You Feel It? system. Each colored zone represents the average MMI from reports in that area.
Source: U.S. Geological Survey Did You Feel It?. View on USGS · submit your own report
Earthquake Details
142.1384°E
Technical Information
Nearby Earthquakes (Last 7 Days)
Common Questions
How strong was the magnitude 4.3 earthquake near Iwaizumi, Japan?
The magnitude 4.3 earthquake that struck 31 km ENE of Iwaizumi, Japan on May 9, 2023 at 18:02 UTC had a depth of 52.5 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 4.3 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 4.3 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 4.3 earthquakes are often felt but rarely cause damage.
Authoritative source: USGS event page (event ID: us6000kap2). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2023, May 9, 2023). M4.3 Earthquake 31 km ENE of Iwaizumi, Japan — May 9, 2023. Retrieved July 22, 2023 from https://www.earthquaketracker.org/earthquakes/event/us6000kap2/