4.6

M4.6 Earthquake 176 km S of Attu Station, Alaska — November 30, 2020

2020-11-30 21:35:48 UTC (2020-11-30) · approx. 9:35 AM UTC+12 local

MagnitudeM4.6(mb)
Time21:35 UTC≈ 9:35 AM UTC+12
Depth10.0 kmshallow crustal
Coordinates51.266°, 173.368°
Felt byNo felt reports
Status✓ Reviewed by USGS

On November 30, 2020 at 21:35 UTC, a magnitude 4.6 shallow crustal earthquake struck 176 km S of Attu Station, Alaska, at a depth of 10.0 km and coordinates 51.2664°, 173.3678°.

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 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 51.27°, 173.37°

Earthquake Details

Magnitude
4.6 mb
Depth
10.0 km
shallow crustal
Location
51.2664°N
173.3678°E

Technical Information

Event ID
us7000claq
Event Type
earthquake
Status
✓ Reviewed
Significance
326
Azimuthal Gap
104.0°
Min Station Distance
1.533°
RMS Residual
0.66 sec
Last Updated
2021-02-06 18:29:21 UTC

Common Questions

How strong was the magnitude 4.6 earthquake near Attu Station, Alaska?

The magnitude 4.6 earthquake that struck 176 km S of Attu Station, Alaska on November 30, 2020 at 21:35 UTC had a depth of 10.0 km. For context, this was a light earthquake commonly felt near the epicenter.

Where did the earthquake occur?

The earthquake epicenter was located at 51.2664°, 173.3678°, which is 176 km S of Attu Station, Alaska. View all earthquakes in Alaska.

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 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 4.6 event is significantly smaller than that historical record.

Authoritative source: USGS event page (event ID: us7000claq). All scientific values on this page are sourced verbatim from the USGS feed.

Cite this page: EarthquakeTracker.org. (2020, November 30, 2020). M4.6 Earthquake 176 km S of Attu Station, Alaska — November 30, 2020. Retrieved February 6, 2021 from https://www.earthquaketracker.org/earthquakes/event/us7000claq/