4.9

M4.9 Earthquake in the South Sandwich Islands regionAugust 29, 2023

2023-08-29 12:50:10 UTC (2023-08-29) · approx. 10:50 AM UTC-2 local

MagnitudeM4.9(mb)
Time12:50 UTC10:50 AM UTC-2
Depth74.3 kmintermediate depth
Coordinates-57.486°, -26.026°
Felt byNo felt reports
Status✓ Reviewed by USGS

On August 29, 2023 at 12:50 UTC, a magnitude 4.9 intermediate depth earthquake struck in the South Sandwich Islands region, at a depth of 74.3 km and coordinates -57.4860°, -26.0261°. This earthquake was detected by 60 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

Map showing earthquake epicenter at -57.49°, -26.03°

Earthquake Details

Magnitude
4.9 mb
Depth
74.3 km
intermediate depth
Location
-57.4860°N
-26.0261°E

Technical Information

Event ID
us7000kt6z
Event Type
earthquake
Status
✓ Reviewed
Significance
369
Stations Used
60
Azimuthal Gap
54.0°
Min Station Distance
6.702°
RMS Residual
0.60 sec
Last Updated
2023-11-04 21:36:21 UTC

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 August 29, 2023 at 12:50 UTC had a depth of 74.3 km. For context, this was a light earthquake commonly felt near the epicenter.

Where did the earthquake occur?

The earthquake epicenter was located at -57.4860°, -26.0261°, 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.

Authoritative source: USGS event page (event ID: us7000kt6z). All scientific values on this page are sourced verbatim from the USGS feed.

Cite this page: EarthquakeTracker.org. (2023, August 29, 2023). M4.9 Earthquake in the South Sandwich Islands regionAugust 29, 2023. Retrieved November 4, 2023 from https://www.earthquaketracker.org/earthquakes/event/us7000kt6z/