M5.6 Earthquake east of the South Sandwich Islands — July 27, 2025
2025-07-27 09:30:37 UTC (2025-07-27) · approx. 8:30 AM UTC-1 local
0Aftershock of the M5.7 mainshock.
On July 27, 2025 at 09:30 UTC, a magnitude 5.6 shallow crustal earthquake struck east of the South Sandwich Islands, at a depth of 10.0 km and coordinates -60.0878°, -18.7450°. This earthquake was detected by 77 seismic stations with excellent location accuracy and was assigned a USGS significance rating of 482, placing it among routine seismic activity.
Physical scale: An earthquake of magnitude 5.6 releases seismic energy equivalent to roughly 4 kilotons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 4.4 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 5.7 mainshock that occurred 8 days ago east of the South Sandwich Islands. Since the mainshock, the USGS has recorded 0 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 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
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
Earthquake Details
-18.7450°E
Technical Information
Nearby Earthquakes (Last 7 Days)
Common Questions
How strong was the magnitude 5.6 earthquake east of the South Sandwich Islands?
The magnitude 5.6 earthquake that struck east of the South Sandwich Islands on July 27, 2025 at 09:30 UTC had a depth of 10.0 km. For context, this was a moderate earthquake that could be widely felt.
Where did the earthquake occur?
The earthquake epicenter was located at -60.0878°, -18.7450°, which is east of the South Sandwich Islands.
Were there aftershocks?
Aftershock activity is monitored continuously by the USGS. Aftershock sequences from magnitude 5.6 earthquakes can continue for days to weeks and gradually diminish over time.
Is this the same earthquake as the M5.7 one earlier?
No. This magnitude 5.6 earthquake is an aftershock of the larger magnitude 5.7 mainshock that occurred earlier east of the South Sandwich Islands. Aftershocks are smaller earthquakes triggered by stress changes from the mainshock.
Actions
Authoritative source: USGS event page (event ID: us6000qvgw). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2025, July 27, 2025). M5.6 Earthquake east of the South Sandwich Islands — July 27, 2025. Retrieved October 11, 2025 from https://www.earthquaketracker.org/earthquakes/event/us6000qvgw/