4.2

M4.2 Earthquake 22 km NE of Hachinohe, JapanOctober 31, 2021

2021-10-31 23:27:25 UTC (2021-10-31) · approx. 8:27 AM UTC+9 local

MagnitudeM4.2(mb)
Time23:27 UTC8:27 AM UTC+9
Depth90.6 kmintermediate depth
Coordinates40.621°, 141.710°
Felt byNo felt reports
Status✓ Reviewed by USGS

On October 31, 2021 at 23:27 UTC, a magnitude 4.2 intermediate depth earthquake struck 22 km NE of Hachinohe, Japan, at a depth of 90.6 km and coordinates 40.6211°, 141.7102°.

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 40.62°, 141.71°

Earthquake Details

Magnitude
4.2 mb
Depth
90.6 km
intermediate depth
Location
40.6211°N
141.7102°E

Technical Information

Event ID
us7000fqce
Event Type
earthquake
Status
✓ Reviewed
Significance
271
Azimuthal Gap
130.0°
Min Station Distance
0.518°
RMS Residual
0.65 sec
Last Updated
2022-01-14 17:58:48 UTC

Common Questions

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

The magnitude 4.2 earthquake that struck 22 km NE of Hachinohe, Japan on October 31, 2021 at 23:27 UTC had a depth of 90.6 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.

Understanding This Data

Magnitude 4.2 earthquakes are often felt but rarely cause damage.

Learn more about magnitude →

Authoritative source: USGS event page (event ID: us7000fqce). All scientific values on this page are sourced verbatim from the USGS feed.

Cite this page: EarthquakeTracker.org. (2021, October 31, 2021). M4.2 Earthquake 22 km NE of Hachinohe, JapanOctober 31, 2021. Retrieved January 14, 2022 from https://www.earthquaketracker.org/earthquakes/event/us7000fqce/