M5.4 Earthquake in the Tristan da Cunha region — July 21, 2021
2021-07-21 02:19:04 UTC (2021-07-21) · approx. 1:19 AM UTC-1 local
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On July 21, 2021 at 02:19 UTC, a magnitude 5.4 shallow crustal earthquake struck in the Tristan da Cunha region, at a depth of 10.0 km and coordinates -35.4664°, -15.8251°. The USGS PAGER system issued a green alert level for this event, indicating no significant casualties or damage expected.
Physical scale: An earthquake of magnitude 5.4 releases seismic energy equivalent to roughly 2 kilotons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 3.2 km — a useful intuition for the size of the slip patch on the fault.
Earthquake Details
-15.8251°E
Technical Information
Common Questions
How strong was the magnitude 5.4 earthquake in the Tristan da Cunha region?
The magnitude 5.4 earthquake that struck in the Tristan da Cunha region on July 21, 2021 at 02:19 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 -35.4664°, -15.8251°, which is in the Tristan da Cunha region.
Were there aftershocks?
Aftershock activity is monitored continuously by the USGS. Aftershock sequences from magnitude 5.4 earthquakes can continue for days to weeks and gradually diminish over time.
Actions
Authoritative source: USGS event page (event ID: us6000exi9). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2021, July 21, 2021). M5.4 Earthquake in the Tristan da Cunha region — July 21, 2021. Retrieved December 22, 2025 from https://www.earthquaketracker.org/earthquakes/event/us6000exi9/