M4.5 Earthquake 29 km NE of San Martín, Argentina — October 23, 2025
2025-10-23 21:22:01 UTC (2025-10-23) · approx. 4:22 PM UTC-5 local
Felt by 1 person across nearby locations.
On October 23, 2025 at 21:22 UTC, a magnitude 4.5 intermediate depth earthquake struck 29 km NE of San Martín, Argentina, at a depth of 109.6 km and coordinates -31.2417°, -68.2875°. This earthquake was detected by 36 seismic stations with excellent location accuracy and was assigned a USGS significance rating of 312, placing it among routine seismic activity.
Physical scale: An earthquake of magnitude 4.5 releases seismic energy equivalent to roughly 85 metric tons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 767 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
-68.2875°E
Technical Information
Nearby Earthquakes (Last 7 Days)
Common Questions
How strong was the magnitude 4.5 earthquake near San Martín, Argentina?
The magnitude 4.5 earthquake that struck 29 km NE of San Martín, Argentina on October 23, 2025 at 21:22 UTC had a depth of 109.6 km. For context, this was a light earthquake commonly felt near the epicenter.
Where did the earthquake occur?
The earthquake epicenter was located at -31.2417°, -68.2875°, which is 29 km NE of San Martín, Argentina.
Were there aftershocks?
Aftershock activity is monitored continuously by the USGS. Aftershock sequences from magnitude 4.5 earthquakes can continue for several days and gradually diminish over time.
What should I do after an earthquake?
If you were in the affected area: check yourself and others for injuries, inspect your home for damage, and be prepared for aftershocks. For detailed guidance, see our earthquake safety guide and emergency planning resources.
Authoritative source: USGS event page (event ID: us6000rj0i). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2025, October 23, 2025). M4.5 Earthquake 29 km NE of San Martín, Argentina — October 23, 2025. Retrieved May 26, 2026 from https://www.earthquaketracker.org/earthquakes/event/us6000rj0i/