3.1

M3.1 Earthquake 81 km SSW of Kaktovik, Alaska — March 20, 2021

2021-03-20 21:19:44 UTC (2021-03-20) · approx. 11:19 AM UTC-10 local

MagnitudeM3.1(ml)
Time21:19 UTC≈ 11:19 AM UTC-10
Depth1.2 kmshallow crustal
Coordinates69.419°, -144.130°
Felt byNo felt reports
Status✓ Reviewed by USGS

On March 20, 2021 at 21:19 UTC, a magnitude 3.1 shallow crustal earthquake struck 81 km SSW of Kaktovik, Alaska, at a depth of 1.2 km and coordinates 69.4193°, -144.1298°.

Physical scale: An earthquake of magnitude 3.1 releases seismic energy equivalent to roughly 674 kg of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 83 m — a useful intuition for the size of the slip patch on the fault.

Map showing earthquake epicenter at 69.42°, -144.13°

Earthquake Details

Magnitude
3.1 ml
Depth
1.2 km
shallow crustal
Location
69.4193°N
-144.1298°E

Technical Information

Event ID
ak0213n02oxi
Event Type
earthquake
Status
✓ Reviewed
Significance
148
RMS Residual
0.51 sec
Last Updated
2021-06-02 15:24:13 UTC

Common Questions

How strong was the magnitude 3.1 earthquake near Kaktovik, Alaska?

The magnitude 3.1 earthquake that struck 81 km SSW of Kaktovik, Alaska on March 20, 2021 at 21:19 UTC had a depth of 1.2 km. For context, this was a minor earthquake typically detected only by instruments.

Were there aftershocks?

Aftershock activity is monitored continuously by the USGS. Aftershock sequences from magnitude 3.1 earthquakes can continue for several days and gradually diminish over time.

Understanding This Data

Magnitude 3.1 earthquakes are typically only recorded by instruments.

Learn more about magnitude →

Authoritative source: USGS event page (event ID: ak0213n02oxi). All scientific values on this page are sourced verbatim from the USGS feed.

Cite this page: EarthquakeTracker.org. (2021, March 20, 2021). M3.1 Earthquake 81 km SSW of Kaktovik, Alaska — March 20, 2021. Retrieved June 2, 2021 from https://www.earthquaketracker.org/earthquakes/event/ak0213n02oxi/