M3.0 Earthquake 8km SSW of Ferndale, CA — December 20, 2021
2021-12-20 23:40:29 UTC (2021-12-20) · approx. 3:40 PM UTC-8 local
On December 20, 2021 at 23:40 UTC, a magnitude 3.0 shallow crustal earthquake struck 8km SSW of Ferndale, CA, at a depth of 18.4 km and coordinates 40.5055°, -124.2960°.
Physical scale: An earthquake of magnitude 3.0 releases seismic energy equivalent to roughly 445 kg of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 69 m — a useful intuition for the size of the slip patch on the fault.
Did You Feel It? — community-reported shaking
Aggregated felt-report intensity from 1 citizen response 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
-124.2960°E
Technical Information
Nearby Earthquakes (Last 7 Days)
Common Questions
How strong was the magnitude 3.0 earthquake near Ferndale, CA?
The magnitude 3.0 earthquake that struck 8km SSW of Ferndale, CA on December 20, 2021 at 23:40 UTC had a depth of 18.4 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 3.0 earthquakes can continue for several days and gradually diminish over time.
Actions
Understanding This Data
Magnitude 3.0 earthquakes are typically only recorded by instruments.
Authoritative source: USGS event page (event ID: nc73666641). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2021, December 20, 2021). M3.0 Earthquake 8km SSW of Ferndale, CA — December 20, 2021. Retrieved March 1, 2022 from https://www.earthquaketracker.org/earthquakes/event/nc73666641/