EARTHQUAKEM5.1

M5.1 earthquake in the South Sandwich Islands region

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

A magnitude 5.1 earthquake struck in the South Sandwich Islands region on Monday, October 19, 2026 at 17:45 UTC, at a depth of 102 km (63 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).

MagnitudeM5.1
Depth102 km (63 mi)
Time (UTC)Oct 19 17:45
Location56.35°S 27.09°W
Energy674 tons TNT
Aftershocks M2.5+1
Tsunami flagNo
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Why here?

This earthquake struck about 91 km (57 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 102 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 5.1 released roughly the energy of 674 tons of TNT. That is about 45 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 4,000,000 times more than this one.

Aftershocks

In the first 6 days after it, USGS recorded 1 smaller earthquake of magnitude 2.5 or more within 100 km (62 mi). It was a magnitude 5.0 on October 22 at 00:25 UTC.

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 130 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 19, 2026 or earthquakes by day.

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