4.6

M4.6 Earthquake 41 km SSE of Kushima, JapanSeptember 6, 2021

2021-09-06 20:59:21 UTC (2021-09-06) · approx. 5:59 AM UTC+9 local

MagnitudeM4.6(mb)
Time20:59 UTC5:59 AM UTC+9
Depth45.9 kmshallow crustal
Coordinates31.167°, 131.467°
Felt byNo felt reports
Status✓ Reviewed by USGS

On September 6, 2021 at 20:59 UTC, a magnitude 4.6 shallow crustal earthquake struck 41 km SSE of Kushima, Japan, at a depth of 45.9 km and coordinates 31.1673°, 131.4674°.

Physical scale: An earthquake of magnitude 4.6 releases seismic energy equivalent to roughly 120 metric tons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 899 m — a useful intuition for the size of the slip patch on the fault.

The epicenter is located in Japan, a region characterized by the intersection of four tectonic plates — Pacific, Philippine Sea, Eurasian, and North American — creating multiple subduction zones. The nearest mapped fault system is the Japan Trench. View all earthquakes in Japan.

Learn more: Magnitude scale · Aftershock sequences

Map showing earthquake epicenter at 31.17°, 131.47°

Earthquake Details

Magnitude
4.6 mb
Depth
45.9 km
shallow crustal
Location
31.1673°N
131.4674°E

Technical Information

Event ID
us7000f8p7
Event Type
earthquake
Status
✓ Reviewed
Significance
326
Azimuthal Gap
102.0°
Min Station Distance
0.932°
RMS Residual
0.95 sec
Last Updated
2021-11-17 17:25:53 UTC

Common Questions

How strong was the magnitude 4.6 earthquake near Kushima, Japan?

The magnitude 4.6 earthquake that struck 41 km SSE of Kushima, Japan on September 6, 2021 at 20:59 UTC had a depth of 45.9 km. For context, this was a light earthquake commonly felt near the epicenter.

Where did the earthquake occur?

The earthquake epicenter was located at 31.1673°, 131.4674°, which is 41 km SSE of Kushima, Japan. View all earthquakes in Japan.

Were there aftershocks?

Aftershock activity is monitored continuously by the USGS. Aftershock sequences from magnitude 4.6 earthquakes can continue for several days and gradually diminish over time.

Has Japan had earthquakes this big before?

The largest recorded earthquake in Japan was the M9.1 Tohoku earthquake of March 11, 2011. Today's magnitude 4.6 event is significantly smaller than that historical record.

Authoritative source: USGS event page (event ID: us7000f8p7). All scientific values on this page are sourced verbatim from the USGS feed.

Cite this page: EarthquakeTracker.org. (2021, September 6, 2021). M4.6 Earthquake 41 km SSE of Kushima, JapanSeptember 6, 2021. Retrieved November 17, 2021 from https://www.earthquaketracker.org/earthquakes/event/us7000f8p7/