4.0

M4.0 Earthquake 11 km NNW of Ōmiya, JapanDecember 29, 2025

2025-12-29 21:00:28 UTC (2025-12-29) · approx. 6:00 AM UTC+9 local

MagnitudeM4.0(mb)
Time21:00 UTC6:00 AM UTC+9
Depth10.0 kmshallow crustal
Coordinates36.636°, 140.355°
Felt byNo felt reports
Status✓ Reviewed by USGS

On December 29, 2025 at 21:00 UTC, a magnitude 4.0 shallow crustal earthquake struck 11 km NNW of Ōmiya, Japan, at a depth of 10.0 km and coordinates 36.6356°, 140.3545°.

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.

Map showing earthquake epicenter at 36.64°, 140.35°

Earthquake Details

Magnitude
4.0 mb
Depth
10.0 km
shallow crustal
Location
36.6356°N
140.3545°E

Technical Information

Event ID
us7000rqwj
Event Type
earthquake
Status
✓ Reviewed
Significance
246
Stations Used
13
Azimuthal Gap
154.0°
Min Station Distance
1.729°
RMS Residual
0.80 sec
Last Updated
2026-04-01 22:49:05 UTC

Common Questions

How strong was the magnitude 4.0 earthquake near Ōmiya, Japan?

The magnitude 4.0 earthquake that struck 11 km NNW of Ōmiya, Japan on December 29, 2025 at 21:00 UTC had a depth of 10.0 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.

What should I do after an earthquake?

If you were in the affected area: check yourself and others for injuries, inspect your home for damage, and be prepared for aftershocks. For detailed guidance, see our earthquake safety guide and emergency planning resources.

Authoritative source: USGS event page (event ID: us7000rqwj). All scientific values on this page are sourced verbatim from the USGS feed.

Cite this page: EarthquakeTracker.org. (2025, December 29, 2025). M4.0 Earthquake 11 km NNW of Ōmiya, JapanDecember 29, 2025. Retrieved May 23, 2026 from https://www.earthquaketracker.org/earthquakes/event/us7000rqwj/