4.2

M4.2 Earthquake 81 km WNW of Amagi, JapanMarch 28, 2026

2026-03-28 17:50:52 UTC (2026-03-28) · approx. 2:50 AM UTC+9 local

MagnitudeM4.2(mb)
Time17:50 UTC2:50 AM UTC+9
Depth10.0 kmshallow crustal
Coordinates28.074°, 128.126°
Felt byNo felt reports
Status✓ Reviewed by USGS

On March 28, 2026 at 17:50 UTC, a magnitude 4.2 shallow crustal earthquake struck 81 km WNW of Amagi, Japan, at a depth of 10.0 km and coordinates 28.0740°, 128.1262°.

Physical scale: An earthquake of magnitude 4.2 releases seismic energy equivalent to roughly 30 metric tons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 476 m — a useful intuition for the size of the slip patch on the fault.

Map showing earthquake epicenter at 28.07°, 128.13°

Earthquake Details

Magnitude
4.2 mb
Depth
10.0 km
shallow crustal
Location
28.0740°N
128.1262°E

Technical Information

Event ID
us7000sb6b
Event Type
earthquake
Status
✓ Reviewed
Significance
271
Stations Used
45
Azimuthal Gap
84.0°
Min Station Distance
1.240°
RMS Residual
0.65 sec
Last Updated
2026-04-23 18:18:41 UTC

Common Questions

How strong was the magnitude 4.2 earthquake near Amagi, Japan?

The magnitude 4.2 earthquake that struck 81 km WNW of Amagi, Japan on March 28, 2026 at 17:50 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 4.2 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: us7000sb6b). All scientific values on this page are sourced verbatim from the USGS feed.

Cite this page: EarthquakeTracker.org. (2026, March 28, 2026). M4.2 Earthquake 81 km WNW of Amagi, JapanMarch 28, 2026. Retrieved May 20, 2026 from https://www.earthquaketracker.org/earthquakes/event/us7000sb6b/