3.1

M3.1 Earthquake 104 km S of Unalaska, Alaska — September 5, 2020

2020-09-05 22:17:41 UTC (2020-09-05) · approx. 11:17 AM UTC-11 local

MagnitudeM3.1(ml)
Time22:17 UTC≈ 11:17 AM UTC-11
Depth39.6 kmshallow crustal
Coordinates52.941°, -166.680°
Felt byNo felt reports
Status✓ Reviewed by USGS

On September 5, 2020 at 22:17 UTC, a magnitude 3.1 shallow crustal earthquake struck 104 km S of Unalaska, Alaska, at a depth of 39.6 km and coordinates 52.9408°, -166.6802°.

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 52.94°, -166.68°

Earthquake Details

Magnitude
3.1 ml
Depth
39.6 km
shallow crustal
Location
52.9408°N
-166.6802°E

Technical Information

Event ID
us7000bppa
Event Type
earthquake
Status
✓ Reviewed
Significance
148
Azimuthal Gap
208.0°
Min Station Distance
0.862°
RMS Residual
0.29 sec
Last Updated
2020-11-17 19:44:41 UTC

Common Questions

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

The magnitude 3.1 earthquake that struck 104 km S of Unalaska, Alaska on September 5, 2020 at 22:17 UTC had a depth of 39.6 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: us7000bppa). All scientific values on this page are sourced verbatim from the USGS feed.

Cite this page: EarthquakeTracker.org. (2020, September 5, 2020). M3.1 Earthquake 104 km S of Unalaska, Alaska — September 5, 2020. Retrieved November 17, 2020 from https://www.earthquaketracker.org/earthquakes/event/us7000bppa/