3.5

M3.5 Earthquake 117 km SW of Nikolski, AlaskaFebruary 14, 2023

2023-02-14 20:08:51 UTC (2023-02-14) · approx. 9:08 AM UTC-11 local

MagnitudeM3.5(ml)
Time20:08 UTC9:08 AM UTC-11
Depth35.0 kmshallow crustal
Coordinates52.232°, -170.143°
Felt byNo felt reports
Status✓ Reviewed by USGS

On February 14, 2023 at 20:08 UTC, a magnitude 3.5 shallow crustal earthquake struck 117 km SW of Nikolski, Alaska, at a depth of 35.0 km and coordinates 52.2321°, -170.1427°.

Physical scale: An earthquake of magnitude 3.5 releases seismic energy equivalent to roughly 2.7 metric tons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 157 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 5.2 mainshock that occurred 11 hours ago 78 km SSW of Nikolski, Alaska. Since the mainshock, the USGS has recorded 16 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 52.23°, -170.14°

Earthquake Details

Magnitude
3.5 ml
Depth
35.0 km
shallow crustal
Location
52.2321°N
-170.1427°E

Technical Information

Event ID
us6000jqpb
Event Type
earthquake
Status
✓ Reviewed
Significance
188
Stations Used
16
Azimuthal Gap
214.0°
Min Station Distance
0.612°
RMS Residual
0.91 sec
Last Updated
2023-04-22 21:33:23 UTC

Common Questions

How strong was the magnitude 3.5 earthquake near Nikolski, Alaska?

The magnitude 3.5 earthquake that struck 117 km SW of Nikolski, Alaska on February 14, 2023 at 20:08 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 3.5 earthquakes can continue for several days and gradually diminish over time.

Is this the same earthquake as the M5.2 one earlier?

No. This magnitude 3.5 earthquake is an aftershock of the larger magnitude 5.2 mainshock that occurred earlier 78 km SSW of Nikolski, Alaska. Aftershocks are smaller earthquakes triggered by stress changes from the mainshock.

Understanding This Data

Magnitude 3.5 earthquakes are typically only recorded by instruments.

Learn more about magnitude →

Authoritative source: USGS event page (event ID: us6000jqpb). All scientific values on this page are sourced verbatim from the USGS feed.

Cite this page: EarthquakeTracker.org. (2023, February 14, 2023). M3.5 Earthquake 117 km SW of Nikolski, AlaskaFebruary 14, 2023. Retrieved April 22, 2023 from https://www.earthquaketracker.org/earthquakes/event/us6000jqpb/