4.1

M4.1 Earthquake 129 km ESE of Iwaki, JapanMay 3, 2023

2023-05-03 21:54:24 UTC (2023-05-03) · approx. 6:54 AM UTC+9 local

MagnitudeM4.1(mb)
Time21:54 UTC6:54 AM UTC+9
Depth31.8 kmshallow crustal
Coordinates36.711°, 142.272°
Felt byNo felt reports
Status✓ Reviewed by USGS

On May 3, 2023 at 21:54 UTC, a magnitude 4.1 shallow crustal earthquake struck 129 km ESE of Iwaki, Japan, at a depth of 31.8 km and coordinates 36.7108°, 142.2723°.

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.

Map showing earthquake epicenter at 36.71°, 142.27°

Earthquake Details

Magnitude
4.1 mb
Depth
31.8 km
shallow crustal
Location
36.7108°N
142.2723°E

Technical Information

Event ID
us6000kama
Event Type
earthquake
Status
✓ Reviewed
Significance
259
Stations Used
30
Azimuthal Gap
160.0°
Min Station Distance
3.273°
RMS Residual
0.84 sec
Last Updated
2023-07-15 22:10:20 UTC

Common Questions

How strong was the magnitude 4.1 earthquake near Iwaki, Japan?

The magnitude 4.1 earthquake that struck 129 km ESE of Iwaki, Japan on May 3, 2023 at 21:54 UTC had a depth of 31.8 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.

Understanding This Data

Magnitude 4.1 earthquakes are often felt but rarely cause damage.

Learn more about magnitude →

Authoritative source: USGS event page (event ID: us6000kama). All scientific values on this page are sourced verbatim from the USGS feed.

Cite this page: EarthquakeTracker.org. (2023, May 3, 2023). M4.1 Earthquake 129 km ESE of Iwaki, JapanMay 3, 2023. Retrieved July 15, 2023 from https://www.earthquaketracker.org/earthquakes/event/us6000kama/