M5.5 Earthquake 78 km W of Vallenar, Chile — December 14, 2021
2021-12-14 04:23:55 UTC (2021-12-14) · approx. 11:23 PM UTC-5 local
Felt by 22 people across nearby locations. Maximum shaking intensity MMI 4.9 (moderate).
On December 14, 2021 at 04:23 UTC, a magnitude 5.5 shallow crustal earthquake struck 78 km W of Vallenar, Chile, at a depth of 17.8 km and coordinates -28.6861°, -71.5555°. The earthquake was reported felt by 22 peopleacross nearby locations, with a maximum shaking intensity of Modified Mercalli Intensity (MMI) 4.9 (moderate). The USGS PAGER system issued a green alert level for this event, indicating no significant casualties or damage expected. The nearest populated place is Vallenar (population 44,895).
Physical scale: An earthquake of magnitude 5.5 releases seismic energy equivalent to roughly 3 kilotons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 3.8 km — a useful intuition for the size of the slip patch on the fault.
The epicenter is located in Chile, a region characterized by the Peru-Chile Trench, where the Nazca Plate subducts beneath South America at 65-80 mm per year. The nearest mapped fault system is the Peru-Chile Trench. View all earthquakes in Chile.
Learn more: Magnitude scale · Aftershock sequences
Nearest Populated Places
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 22 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
Population exposure (USGS PAGER)
Estimated population that experienced each level of shaking. Based on the USGS PAGER rapid impact assessment, which combines ShakeMap output with global population grids.
| Shaking intensity (MMI) | Description | Population exposed |
|---|---|---|
| MMI 3 | weak | 589,738 |
| MMI 4 | light | 18,761 |
| MMI 5 | moderate | 509 |
Earthquake Details
-71.5555°E
Technical Information
Common Questions
How strong was the magnitude 5.5 earthquake near Vallenar, Chile?
The magnitude 5.5 earthquake that struck 78 km W of Vallenar, Chile on December 14, 2021 at 04:23 UTC had a depth of 17.8 km. It was felt by 22 people with maximum shaking intensity of MMI 4.9 (moderate). For context, this was a moderate earthquake that could be widely felt.
Where did the earthquake occur?
The earthquake epicenter was located at -28.6861°, -71.5555°, which is 78 km W of Vallenar, Chile. The nearest populated place is Vallenar (population 44,895). View all earthquakes in Chile.
Were there aftershocks?
Aftershock activity is monitored continuously by the USGS. Aftershock sequences from magnitude 5.5 earthquakes can continue for days to weeks and gradually diminish over time.
Has Chile had earthquakes this big before?
The largest recorded earthquake in Chile was the M9.5 Great Chilean earthquake of May 22, 1960. Today's magnitude 5.5 event is significantly smaller than that historical record.
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Location
Authoritative source: USGS event page (event ID: us6000gc3k). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2021, December 14, 2021). M5.5 Earthquake 78 km W of Vallenar, Chile — December 14, 2021. Retrieved December 22, 2025 from https://www.earthquaketracker.org/earthquakes/event/us6000gc3k/