M4.5 Earthquake in the South Sandwich Islands region — September 17, 2025
2025-09-17 16:03:28 UTC (2025-09-17) · approx. 2:03 PM UTC-2 local
On September 17, 2025 at 16:03 UTC, a magnitude 4.5 intermediate depth earthquake struck in the South Sandwich Islands region, at a depth of 76.2 km and coordinates -56.4232°, -26.6999°. This earthquake was detected by 15 seismic stations with good 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.
The epicenter is located in South Sandwich Islands, a region characterized by the South Sandwich Trench, one of Earth's most remote subduction zones.
Learn more: Magnitude scale · Aftershock sequences
Earthquake Details
-26.6999°E
Technical Information
Nearby Earthquakes (Last 7 Days)
Common Questions
How strong was the magnitude 4.5 earthquake in the South Sandwich Islands region?
The magnitude 4.5 earthquake that struck in the South Sandwich Islands region on September 17, 2025 at 16:03 UTC had a depth of 76.2 km. For context, this was a light earthquake commonly felt near the epicenter.
Where did the earthquake occur?
The earthquake epicenter was located at -56.4232°, -26.6999°, which is in the South Sandwich Islands region.
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: us6000rg6j). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2025, September 17, 2025). M4.5 Earthquake in the South Sandwich Islands region — September 17, 2025. Retrieved May 28, 2026 from https://www.earthquaketracker.org/earthquakes/event/us6000rg6j/