EARTHQUAKEM4.8

M4.8 earthquake in the South Sandwich Islands region

Map: the earthquake in the South Sandwich Islands region, with plate boundaries

A magnitude 4.8 earthquake struck in the South Sandwich Islands region on Monday, October 26, 2026 at 11:01 UTC, at a depth of 174 km (108 mi), according to the U.S. Geological Survey. At this intermediate depth, shaking spreads out before it reaches the surface. It struck far from land: no town on our map lies within 600 km (373 mi).

MagnitudeM4.8
Depth174 km (108 mi)
Time (UTC)Oct 26 11:01
Location59.81°S 27.71°W
Energy239 tons TNT
Aftershocks M2.5+0
Tsunami flagNo
See it on the live 3D globe →Watch live on YouTube🔔 Get alerts near you

Why here?

This earthquake struck about 81 km (51 mi) from the boundary between the South American and Sandwich plates. Most earthquakes happen along plate boundaries like this one, where the pieces of Earth’s outer shell collide, pull apart or grind past each other. Stress builds up over years until the rock suddenly slips. At 174 km down, it most likely broke inside a plate that is sinking into the mantle beneath its neighbor, in what geologists call a subduction zone.

The red lines on the map are plate boundaries.

How strong was it?

Magnitude is logarithmic: each whole step releases about 32 times more energy. This magnitude 4.8 released roughly the energy of 239 tons of TNT. That is about 16 times the energy of a magnitude 4.0, a quake people nearby feel but that rarely causes damage. The strongest earthquake ever recorded, magnitude 9.5 in Chile in 1960, released about 11,000,000 times more than this one.

Aftershocks

In the first 5 hours after it, USGS recorded no smaller earthquakes of magnitude 2.5 or more within 100 km (62 mi).

Outside the United States, USGS mainly lists quakes of about magnitude 4 and up, so smaller aftershocks there are undercounted.

Earthquake history here

Before this earthquake, USGS had recorded 96 earthquakes of magnitude 6 or larger within 300 km (186 mi) since 1900. The strongest:

Official details, updates and the shaking map: USGS event page.

See every earthquake on October 26, 2026 or earthquakes by day.

More from around the world