M4.2 Earthquake 41 km E of Pedro Bay, Alaska — March 22, 2021
2021-03-22 17:41:47 UTC (2021-03-22) · approx. 7:41 AM UTC-10 local
Felt by 48 people across nearby locations.
On March 22, 2021 at 17:41 UTC, a magnitude 4.2 intermediate depth earthquake struck 41 km E of Pedro Bay, Alaska, at a depth of 130.2 km and coordinates 59.8435°, -153.3672°.
Physical scale: An earthquake of magnitude 4.2 releases seismic energy equivalent to roughly 30 metric tons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 476 m — a useful intuition for the size of the slip patch on the fault.
The epicenter is located in Alaska, a region characterized by Pacific Plate subduction beneath the North American Plate, producing frequent megathrust and crustal earthquakes along the Aleutian arc. The nearest mapped fault system is the Aleutian megathrust. View all earthquakes in Alaska.
Learn more: Magnitude scale · Aftershock sequences
Did You Feel It? — community-reported shaking
Aggregated felt-report intensity from 48 citizen responses to the USGS Did You Feel It? system. Each colored zone represents the average MMI from reports in that area.
Source: U.S. Geological Survey Did You Feel It?. View on USGS · submit your own report
Earthquake Details
-153.3672°E
Technical Information
Nearby Earthquakes (Last 7 Days)
Common Questions
How strong was the magnitude 4.2 earthquake near Pedro Bay, Alaska?
The magnitude 4.2 earthquake that struck 41 km E of Pedro Bay, Alaska on March 22, 2021 at 17:41 UTC had a depth of 130.2 km. For context, this was a light earthquake commonly felt near the epicenter.
Where did the earthquake occur?
The earthquake epicenter was located at 59.8435°, -153.3672°, which is 41 km E of Pedro Bay, Alaska. View all earthquakes in Alaska.
Were there aftershocks?
Aftershock activity is monitored continuously by the USGS. Aftershock sequences from magnitude 4.2 earthquakes can continue for several days and gradually diminish over time.
Has Alaska had earthquakes this big before?
The largest recorded earthquake in Alaska was the M9.2 Great Alaska earthquake of March 27, 1964. Today's magnitude 4.2 event is significantly smaller than that historical record.
Authoritative source: USGS event page (event ID: ak0213q8wdal). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2021, March 22, 2021). M4.2 Earthquake 41 km E of Pedro Bay, Alaska — March 22, 2021. Retrieved June 2, 2021 from https://www.earthquaketracker.org/earthquakes/event/ak0213q8wdal/