5.3

M5.3 Earthquake 5 km SSE of Point MacKenzie, Alaska — February 27, 2021

2021-02-27 18:59:25 UTC (2021-02-27) · approx. 8:59 AM UTC-10 local

MagnitudeM5.3(mww)
Time18:59 UTC≈ 8:59 AM UTC-10
Depth46.0 kmshallow crustal
Coordinates61.319°, -149.933°
Felt byNo felt reports
Status✓ Reviewed by USGS

On February 27, 2021 at 18:59 UTC, a magnitude 5.3 shallow crustal earthquake struck 5 km SSE of Point MacKenzie, Alaska, at a depth of 46.0 km and coordinates 61.3190°, -149.9334°.

Physical scale: An earthquake of magnitude 5.3 releases seismic energy equivalent to roughly 1 kilotons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 2.7 km — a useful intuition for the size of the slip patch on the fault.

The epicenter is located in Alaska, a region characterized by Pacific Plate subduction beneath the North American Plate, producing frequent megathrust and crustal earthquakes along the Aleutian arc. The nearest mapped fault system is the Aleutian megathrust. View all earthquakes in Alaska.

Learn more: Magnitude scale · Aftershock sequences

Map showing earthquake epicenter at 61.32°, -149.93°

Earthquake Details

Magnitude
5.3 mww
Depth
46.0 km
shallow crustal
Location
61.3190°N
-149.9334°E

Technical Information

Event ID
ak0212o88mqd
Event Type
earthquake
Status
✓ Reviewed
Significance
432
RMS Residual
1.08 sec
Last Updated
2025-12-22 18:51:42 UTC

Common Questions

How strong was the magnitude 5.3 earthquake near Point MacKenzie, Alaska?

The magnitude 5.3 earthquake that struck 5 km SSE of Point MacKenzie, Alaska on February 27, 2021 at 18:59 UTC had a depth of 46.0 km. For context, this was a moderate earthquake that could be widely felt.

Where did the earthquake occur?

The earthquake epicenter was located at 61.3190°, -149.9334°, which is 5 km SSE of Point MacKenzie, Alaska. View all earthquakes in Alaska.

Were there aftershocks?

Aftershock activity is monitored continuously by the USGS. Aftershock sequences from magnitude 5.3 earthquakes can continue for days to weeks and gradually diminish over time.

Has Alaska had earthquakes this big before?

The largest recorded earthquake in Alaska was the M9.2 Great Alaska earthquake of March 27, 1964. Today's magnitude 5.3 event is significantly smaller than that historical record.

Authoritative source: USGS event page (event ID: ak0212o88mqd). All scientific values on this page are sourced verbatim from the USGS feed.

Cite this page: EarthquakeTracker.org. (2021, February 27, 2021). M5.3 Earthquake 5 km SSE of Point MacKenzie, Alaska — February 27, 2021. Retrieved December 22, 2025 from https://www.earthquaketracker.org/earthquakes/event/ak0212o88mqd/