M5.0 Earthquake in the South Sandwich Islands region — November 12, 2025

On November 12, 2025 at 04:23 UTC, a magnitude 5.0 shallow crustal earthquake struck in the South Sandwich Islands region, at a depth of 10.0 km and coordinates -55.2986°, -27.0243°. This earthquake was detected by 36 seismic stations with good location accuracy and was assigned a USGS significance rating of 385, placing it among routine seismic activity.

Physical scale: An earthquake of magnitude 5.0 releases seismic energy equivalent to roughly 477 metric tons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 1.7 km — a useful intuition for the size of the slip patch on the fault.

This earthquake is part of an ongoing aftershock sequence following the magnitude 5.1 mainshock that occurred 15 days ago in the South Sandwich Islands region. Since the mainshock, the USGS has recorded 1 aftershocks in this area. Aftershock activity is expected to continue for days to weeks as stresses on surrounding faults redistribute.

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