4.2

M4.2 Earthquake in the Kermadec Islands regionAugust 25, 2021

2021-08-25 19:12:00 UTC (2021-08-25) · approx. 7:12 AM UTC-12 local

MagnitudeM4.2(mb)
Time19:12 UTC7:12 AM UTC-12
Depth404.0 kmdeep-focus
Coordinates-31.173°, -179.850°
Felt byNo felt reports
Status✓ Reviewed by USGS

On August 25, 2021 at 19:12 UTC, a magnitude 4.2 deep-focus earthquake struck in the Kermadec Islands region, at a depth of 404.0 km and coordinates -31.1730°, -179.8500°.

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 -31.17°, -179.85°

Earthquake Details

Magnitude
4.2 mb
Depth
404.0 km
deep-focus
Location
-31.1730°N
-179.8500°E

Technical Information

Event ID
us7000f3v3
Event Type
earthquake
Status
✓ Reviewed
Significance
271
Azimuthal Gap
154.0°
Min Station Distance
6.553°
RMS Residual
0.85 sec
Last Updated
2021-11-02 14:55:15 UTC

Common Questions

How strong was the magnitude 4.2 earthquake in the Kermadec Islands region?

The magnitude 4.2 earthquake that struck in the Kermadec Islands region on August 25, 2021 at 19:12 UTC had a depth of 404.0 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.

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: us7000f3v3). All scientific values on this page are sourced verbatim from the USGS feed.

Cite this page: EarthquakeTracker.org. (2021, August 25, 2021). M4.2 Earthquake in the Kermadec Islands regionAugust 25, 2021. Retrieved November 2, 2021 from https://www.earthquaketracker.org/earthquakes/event/us7000f3v3/