M4.2 Earthquake 51 km NNE of Calama, Chile — September 29, 2025
2025-09-29 17:40:17 UTC (2025-09-29) · approx. 12:40 PM UTC-5 local
On September 29, 2025 at 17:40 UTC, a magnitude 4.2 intermediate depth earthquake struck 51 km NNE of Calama, Chile, at a depth of 108.2 km and coordinates -22.0099°, -68.7948°.
Physical scale: An earthquake of magnitude 4.2 releases seismic energy equivalent to roughly 30 metric tons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 476 m — 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 5.1 mainshock that occurred 21 hours ago 26 km NE of Calama, Chile. Since the mainshock, the USGS has recorded 8 aftershocks in this area. Aftershock activity is expected to continue for days to weeks as stresses on surrounding faults redistribute.
Earthquake Details
-68.7948°E
Technical Information
Nearby Earthquakes (Last 7 Days)
Common Questions
How strong was the magnitude 4.2 earthquake near Calama, Chile?
The magnitude 4.2 earthquake that struck 51 km NNE of Calama, Chile on September 29, 2025 at 17:40 UTC had a depth of 108.2 km. For context, this was a light earthquake commonly felt near the epicenter.
Were there aftershocks?
Aftershock activity is monitored continuously by the USGS. Aftershock sequences from magnitude 4.2 earthquakes can continue for several days and gradually diminish over time.
Is this the same earthquake as the M5.1 one earlier?
No. This magnitude 4.2 earthquake is an aftershock of the larger magnitude 5.1 mainshock that occurred earlier 26 km NE of Calama, Chile. Aftershocks are smaller earthquakes triggered by stress changes from the mainshock.
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.
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Understanding This Data
Magnitude 4.2 earthquakes are often felt but rarely cause damage.
Authoritative source: USGS event page (event ID: us6000rdma). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2025, September 29, 2025). M4.2 Earthquake 51 km NNE of Calama, Chile — September 29, 2025. Retrieved May 28, 2026 from https://www.earthquaketracker.org/earthquakes/event/us6000rdma/