3.3

M3.3 Earthquake 236 km SSE of False Pass, Alaska — October 6, 2020

2020-10-06 20:36:33 UTC (2020-10-06) · approx. 9:36 AM UTC-11 local

MagnitudeM3.3(ml)
Time20:36 UTC≈ 9:36 AM UTC-11
Depth10.0 kmshallow crustal
Coordinates52.831°, -162.314°
Felt byNo felt reports
Status✓ Reviewed by USGS

On October 6, 2020 at 20:36 UTC, a magnitude 3.3 shallow crustal earthquake struck 236 km SSE of False Pass, Alaska, at a depth of 10.0 km and coordinates 52.8312°, -162.3137°.

Physical scale: An earthquake of magnitude 3.3 releases seismic energy equivalent to roughly 1.3 metric tons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 114 m — a useful intuition for the size of the slip patch on the fault.

This earthquake is part of an ongoing aftershock sequence following the magnitude 5.0 mainshock that occurred 16 days ago 244 km SSE of False Pass, Alaska. Since the mainshock, the USGS has recorded 0 aftershocks in this area. Aftershock activity is expected to continue for days to weeks as stresses on surrounding faults redistribute.

Map showing earthquake epicenter at 52.83°, -162.31°

Earthquake Details

Magnitude
3.3 ml
Depth
10.0 km
shallow crustal
Location
52.8312°N
-162.3137°E

Technical Information

Event ID
us6000cc9h
Event Type
earthquake
Status
✓ Reviewed
Significance
168
Azimuthal Gap
243.0°
Min Station Distance
2.133°
RMS Residual
1.25 sec
Last Updated
2020-12-12 22:28:54 UTC

Common Questions

How strong was the magnitude 3.3 earthquake near False Pass, Alaska?

The magnitude 3.3 earthquake that struck 236 km SSE of False Pass, Alaska on October 6, 2020 at 20:36 UTC had a depth of 10.0 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 3.3 earthquakes can continue for several days and gradually diminish over time.

Is this the same earthquake as the M5.0 one earlier?

No. This magnitude 3.3 earthquake is an aftershock of the larger magnitude 5.0 mainshock that occurred earlier 244 km SSE of False Pass, Alaska. Aftershocks are smaller earthquakes triggered by stress changes from the mainshock.

Understanding This Data

Magnitude 3.3 earthquakes are typically only recorded by instruments.

Learn more about magnitude →

Authoritative source: USGS event page (event ID: us6000cc9h). All scientific values on this page are sourced verbatim from the USGS feed.

Cite this page: EarthquakeTracker.org. (2020, October 6, 2020). M3.3 Earthquake 236 km SSE of False Pass, Alaska — October 6, 2020. Retrieved December 12, 2020 from https://www.earthquaketracker.org/earthquakes/event/us6000cc9h/