M4.9 Earthquake in the South Sandwich Islands region

On July 2, 2026 at 02:17 UTC, a magnitude 4.9 intermediate depth earthquake struck in the South Sandwich Islands region, at a depth of 110.4 km and coordinates -59.4795°, -26.1998°. This earthquake was detected by 48 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.

This earthquake is part of an ongoing aftershock sequence following the magnitude 5.1 mainshock that occurred 12 days ago in the South Sandwich Islands region. Since the mainshock, the USGS has recorded 0 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

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 July 2, 2026 at 02:17 UTC had a depth of 110.4 km. For context, this was a light earthquake commonly felt near the epicenter.

Where did the earthquake occur?

The earthquake epicenter was located at -59.4795°, -26.1998°, 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.

Is this the same earthquake as the M5.1 one earlier?

No. This magnitude 4.9 earthquake is an aftershock of the larger magnitude 5.1 mainshock that occurred earlier in the South Sandwich Islands region. Aftershocks are smaller earthquakes triggered by stress changes from the mainshock.

What should I do after an earthquake?

If you were in the affected area: check yourself and others for injuries, inspect your home for damage, and be prepared for aftershocks. For detailed guidance, see our earthquake safety guide and emergency planning resources.

M4.9 Earthquake in the South Sandwich Islands region — July 2, 2026

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