M6.9 Earthquake near South Shetland Islands — January 23, 2021
2021-01-23 23:36:51 UTC (2021-01-23) · approx. 7:36 PM UTC-4 local
Felt by 8 people across nearby locations. Maximum shaking intensity MMI 5.2 (strong).
On January 23, 2021 at 23:36 UTC, a magnitude 6.9 shallow crustal earthquake struck near South Shetland Islands, at a depth of 15.0 km and coordinates -61.8098°, -55.5027°. The earthquake was reported felt by 8 peopleacross nearby locations, with a maximum shaking intensity of Modified Mercalli Intensity (MMI) 5.2 (strong). 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 6.9 releases seismic energy equivalent to roughly 338 kilotons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 35 km — a useful intuition for the size of the slip patch on the fault.
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
Did You Feel It? — community-reported shaking
Aggregated felt-report intensity from 8 citizen responses to the USGS Did You Feel It? system. Each colored zone represents the average MMI from reports in that area.
Source: U.S. Geological Survey Did You Feel It?. View on USGS · submit your own report
Earthquake Details
-55.5027°E
Technical Information
Common Questions
How strong was the magnitude 6.9 earthquake near South Shetland Islands?
The magnitude 6.9 earthquake that struck near South Shetland Islands on January 23, 2021 at 23:36 UTC had a depth of 15.0 km. It was felt by 8 people with maximum shaking intensity of MMI 5.2 (strong). For context, this was a strong earthquake capable of causing significant damage.
Where did the earthquake occur?
The earthquake epicenter was located at -61.8098°, -55.5027°, which is near South Shetland Islands.
Were there aftershocks?
Aftershock activity is monitored continuously by the USGS. Aftershock sequences from magnitude 6.9 earthquakes can continue for weeks to months and gradually diminish over time.
Actions
Authoritative source: USGS event page (event ID: us7000d2rx). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2021, January 23, 2021). M6.9 Earthquake near South Shetland Islands — January 23, 2021. Retrieved December 22, 2025 from https://www.earthquaketracker.org/earthquakes/event/us7000d2rx/