M4.0 Earthquake 158 km SW of Nikolski, Alaska — December 20, 2020
2020-12-20 22:59:14 UTC (2020-12-20) · approx. 11:59 AM UTC-11 local
On December 20, 2020 at 22:59 UTC, a magnitude 4.0 shallow crustal earthquake struck 158 km SW of Nikolski, Alaska, at a depth of 40.9 km and coordinates 51.8731°, -170.4074°.
Physical scale: An earthquake of magnitude 4.0 releases seismic energy equivalent to roughly 15 metric tons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 347 m — a useful intuition for the size of the slip patch on the fault.
Earthquake Details
-170.4074°E
Technical Information
Nearby Earthquakes (Last 7 Days)
Common Questions
How strong was the magnitude 4.0 earthquake near Nikolski, Alaska?
The magnitude 4.0 earthquake that struck 158 km SW of Nikolski, Alaska on December 20, 2020 at 22:59 UTC had a depth of 40.9 km. For context, this was a light earthquake commonly felt near the epicenter.
Were there aftershocks?
Aftershock activity is monitored continuously by the USGS. Aftershock sequences from magnitude 4.0 earthquakes can continue for several days and gradually diminish over time.
Actions
Understanding This Data
Magnitude 4.0 earthquakes are often felt but rarely cause damage.
Authoritative source: USGS event page (event ID: us7000cst3). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2020, December 20, 2020). M4.0 Earthquake 158 km SW of Nikolski, Alaska — December 20, 2020. Retrieved February 27, 2021 from https://www.earthquaketracker.org/earthquakes/event/us7000cst3/