M5.4 Earthquake near off the coast of Oregon — December 9, 2021
2021-12-09 23:32:16 UTC (2021-12-09) · approx. 2:32 PM UTC-9 local
Felt by 1 person across nearby locations. 0
On December 9, 2021 at 23:32 UTC, a magnitude 5.4 shallow crustal earthquake struck near off the coast of Oregon, at a depth of 10.0 km and coordinates 44.1627°, -129.5187°.0 The USGS PAGER system issued a green alert level for this event, indicating no significant casualties or damage expected.
Physical scale: An earthquake of magnitude 5.4 releases seismic energy equivalent to roughly 2 kilotons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 3.2 km — a useful intuition for the size of the slip patch on the fault.
The epicenter is located in Oregon, a region characterized by the southern Cascadia Subduction Zone, with additional seismicity from crustal faults in the Willamette Valley. The nearest mapped fault system is the Cascadia Subduction Zone. View all earthquakes in Oregon.
Learn more: Cascadia Subduction Zone · Magnitude scale · Aftershock sequences
ShakeMap — predicted shaking intensity
Modeled ground-motion intensity contoured on the Modified Mercalli scale (MMI). Computed by the USGS from the moment-tensor solution and regional ground-motion prediction equations.
Source: U.S. Geological Survey ShakeMap. View interactive ShakeMap on USGS
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
-129.5187°E
Technical Information
Common Questions
How strong was the magnitude 5.4 earthquake near off the coast of Oregon?
The magnitude 5.4 earthquake that struck near off the coast of Oregon on December 9, 2021 at 23:32 UTC had a depth of 10.0 km. For context, this was a moderate earthquake that could be widely felt.
Where did the earthquake occur?
The earthquake epicenter was located at 44.1627°, -129.5187°, which is near off the coast of Oregon. View all earthquakes in Oregon.
Were there aftershocks?
Aftershock activity is monitored continuously by the USGS. Aftershock sequences from magnitude 5.4 earthquakes can continue for days to weeks and gradually diminish over time.
Has Oregon had earthquakes this big before?
The largest recorded earthquake in Oregon was the M7.3 offshore Brookings earthquake of November 23, 1873. Today's magnitude 5.4 event is significantly smaller than that historical record.
Authoritative source: USGS event page (event ID: us6000gb13). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2021, December 9, 2021). M5.4 Earthquake near off the coast of Oregon — December 9, 2021. Retrieved December 22, 2025 from https://www.earthquaketracker.org/earthquakes/event/us6000gb13/