M4.9 Earthquake in the South Sandwich Islands region — May 18, 2023
2023-05-18 12:47:50 UTC (2023-05-18) · approx. 10:47 AM UTC-2 local
On May 18, 2023 at 12:47 UTC, a magnitude 4.9 shallow crustal earthquake struck in the South Sandwich Islands region, at a depth of 45.5 km and coordinates -55.7181°, -27.1663°. This earthquake was detected by 29 seismic stations with excellent location accuracy and was assigned a USGS significance rating of 369, placing it among routine seismic activity.
Physical scale: An earthquake of magnitude 4.9 releases seismic energy equivalent to roughly 338 metric tons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 1.4 km — 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
-27.1663°E
Technical Information
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Common Questions
How strong was the magnitude 4.9 earthquake in the South Sandwich Islands region?
The magnitude 4.9 earthquake that struck in the South Sandwich Islands region on May 18, 2023 at 12:47 UTC had a depth of 45.5 km. For context, this was a light earthquake commonly felt near the epicenter.
Where did the earthquake occur?
The earthquake epicenter was located at -55.7181°, -27.1663°, which is in the South Sandwich Islands region.
Were there aftershocks?
Aftershock activity is monitored continuously by the USGS. Aftershock sequences from magnitude 4.9 earthquakes can continue for several days and gradually diminish over time.
Actions
Authoritative source: USGS event page (event ID: us6000kcva). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2023, May 18, 2023). M4.9 Earthquake in the South Sandwich Islands region — May 18, 2023. Retrieved July 24, 2023 from https://www.earthquaketracker.org/earthquakes/event/us6000kcva/