3.6

M3.6 Earthquake 74 km S of Adak, AlaskaDecember 5, 2023

2023-12-05 23:22:23 UTC (2023-12-05) · approx. 11:22 AM UTC-12 local

MagnitudeM3.6(ml)
Time23:22 UTC11:22 AM UTC-12
Depth35.0 kmshallow crustal
Coordinates51.206°, -176.721°
Felt byNo felt reports
Status✓ Reviewed by USGS

On December 5, 2023 at 23:22 UTC, a magnitude 3.6 shallow crustal earthquake struck 74 km S of Adak, Alaska, at a depth of 35.0 km and coordinates 51.2056°, -176.7208°.

Physical scale: An earthquake of magnitude 3.6 releases seismic energy equivalent to roughly 3.8 metric tons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 184 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 5.1 mainshock that occurred 28 days ago 93 km SSE of Adak, Alaska. Since the mainshock, the USGS has recorded 14 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 51.21°, -176.72°

Earthquake Details

Magnitude
3.6 ml
Depth
35.0 km
shallow crustal
Location
51.2056°N
-176.7208°E

Technical Information

Event ID
us7000lkfu
Event Type
earthquake
Status
✓ Reviewed
Significance
199
Stations Used
24
Azimuthal Gap
218.0°
Min Station Distance
0.643°
RMS Residual
0.44 sec
Last Updated
2024-02-10 23:47:36 UTC

Common Questions

How strong was the magnitude 3.6 earthquake near Adak, Alaska?

The magnitude 3.6 earthquake that struck 74 km S of Adak, Alaska on December 5, 2023 at 23:22 UTC had a depth of 35.0 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 3.6 earthquakes can continue for several days and gradually diminish over time.

Is this the same earthquake as the M5.1 one earlier?

No. This magnitude 3.6 earthquake is an aftershock of the larger magnitude 5.1 mainshock that occurred earlier 93 km SSE of Adak, Alaska. Aftershocks are smaller earthquakes triggered by stress changes from the mainshock.

Understanding This Data

Magnitude 3.6 earthquakes are typically only recorded by instruments.

Learn more about magnitude →

Authoritative source: USGS event page (event ID: us7000lkfu). All scientific values on this page are sourced verbatim from the USGS feed.

Cite this page: EarthquakeTracker.org. (2023, December 5, 2023). M3.6 Earthquake 74 km S of Adak, AlaskaDecember 5, 2023. Retrieved February 10, 2024 from https://www.earthquaketracker.org/earthquakes/event/us7000lkfu/