M5.1 Earthquake 85 km WSW of San Antonio, Chile — April 19, 2021
2021-04-19 03:18:57 UTC (2021-04-19) · approx. 10:18 PM UTC-5 local
Felt by 42 people across nearby locations. Aftershock of the M5.2 mainshock.
On April 19, 2021 at 03:18 UTC, a magnitude 5.1 shallow crustal earthquake struck 85 km WSW of San Antonio, Chile, at a depth of 12.8 km and coordinates -33.9739°, -72.4073°.
Physical scale: An earthquake of magnitude 5.1 releases seismic energy equivalent to roughly 674 metric tons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 2.0 km — a useful intuition for the size of the slip patch on the fault.
This earthquake is part of an ongoing aftershock sequence following the magnitude 5.2 mainshock that occurred 3 days ago 62 km SW of San Antonio, Chile. Since the mainshock, the USGS has recorded 1 aftershocks in this area. Aftershock activity is expected to continue for days to weeks as stresses on surrounding faults redistribute.
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
Did You Feel It? — community-reported shaking
Aggregated felt-report intensity from 42 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
-72.4073°E
Technical Information
Nearby Earthquakes (Last 7 Days)
Common Questions
How strong was the magnitude 5.1 earthquake near San Antonio, Chile?
The magnitude 5.1 earthquake that struck 85 km WSW of San Antonio, Chile on April 19, 2021 at 03:18 UTC had a depth of 12.8 km. For context, this was a moderate earthquake that could be widely felt.
Where did the earthquake occur?
The earthquake epicenter was located at -33.9739°, -72.4073°, which is 85 km WSW of San Antonio, Chile. View all earthquakes in Chile.
Were there aftershocks?
Aftershock activity is monitored continuously by the USGS. Aftershock sequences from magnitude 5.1 earthquakes can continue for days to weeks and gradually diminish over time.
Is this the same earthquake as the M5.2 one earlier?
No. This magnitude 5.1 earthquake is an aftershock of the larger magnitude 5.2 mainshock that occurred earlier 62 km SW of San Antonio, Chile. Aftershocks are smaller earthquakes triggered by stress changes from the mainshock.
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 5.1 event is significantly smaller than that historical record.
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Location
Authoritative source: USGS event page (event ID: us6000e2s5). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2021, April 19, 2021). M5.1 Earthquake 85 km WSW of San Antonio, Chile — April 19, 2021. Retrieved December 22, 2025 from https://www.earthquaketracker.org/earthquakes/event/us6000e2s5/