M4.0 Earthquake in the South Sandwich Islands region — June 20, 2025
2025-06-20 23:42:21 UTC (2025-06-20) · approx. 9:42 PM UTC-2 local
On June 20, 2025 at 23:42 UTC, a magnitude 4.0 shallow crustal earthquake struck in the South Sandwich Islands region, at a depth of 29.1 km and coordinates -55.2936°, -28.1682°.
Physical scale: An earthquake of magnitude 4.0 releases seismic energy equivalent to roughly 15 metric tons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 347 m — a useful intuition for the size of the slip patch on the fault.
Earthquake Details
-28.1682°E
Technical Information
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Common Questions
How strong was the magnitude 4.0 earthquake in the South Sandwich Islands region?
The magnitude 4.0 earthquake that struck in the South Sandwich Islands region on June 20, 2025 at 23:42 UTC had a depth of 29.1 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 4.0 earthquakes can continue for several days and gradually diminish over time.
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Understanding This Data
Magnitude 4.0 earthquakes are often felt but rarely cause damage.
Authoritative source: USGS event page (event ID: us7000qagq). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2025, June 20, 2025). M4.0 Earthquake in the South Sandwich Islands region — June 20, 2025. Retrieved September 2, 2025 from https://www.earthquaketracker.org/earthquakes/event/us7000qagq/