| UTC time | 2021-08-12 18:32:52 |
|---|---|
| 2021-08-12 18:35:17 | |
| ISC event | 621237435 |
| 620986442 | |
| USGS-ANSS | ComCat |
| ComCat | |
| Local date | August 12, 2021 |
| Local time | 16:32:52 |
| 16:35:17 | |
| Duration | 4 minutes |
| Magnitude | 7.5 Mw 7.8 Ms |
| 8.1–8.3 Mw[1] 7.8 Ms | |
| Depth | 47.2 km (29.3 mi) |
| 22.8 km (14.2 mi) (USGS) 20.0 km (12.4 mi) (GCMT)[1] 10.0 km (6.2 mi) (GEOFON)[2] | |
| Epicenter | 58°24′58″S 25°19′16″W / 58.416°S 25.321°W |
| Type | Either megathrust or Intraplate |
| Areas affected | South Georgia and the South Sandwich Islands |
| Max. intensity | MMI VII (Very strong) |
| Tsunami | Up to 2.46 ft (0.75 m) at South Georgia Island |
| Aftershocks | 1,968 Mw 4.0+, up to 7.1 Mw[3] |
| Casualties | None |
The 2021 South Sandwich Islands earthquakes were a pair of powerful earthquakes, followed by many strong aftershocks which struck along the South Sandwich Trench in August 2021. The quakes measured 7.5 and 8.1 on the moment magnitude scale, according to the United States Geological Survey.[4][5] The mainshock is tied with another event in 1929 as the largest earthquake ever recorded in the South Atlantic region,[6] and is tied with the 2021 Kermadec Islands earthquake as the second largest earthquake of 2021.
- ^ a b "Global CMT Catalog". Global Centroid Moment Tensor. Retrieved 10 September 2021.
- ^ "GEOFON Program". GFZ. Retrieved 10 September 2021.
- ^ "USGS earthquake catalog". United States Geological Survey.
- ^ "M 7.5 - South Sandwich Islands region". United States Geological Survey. Retrieved 12 August 2021.
- ^ "M 8.1 - South Sandwich Islands region". United States Geological Survey. Retrieved 12 August 2021.
- ^ "M 8.1 - South Sandwich Islands Region". United States Geological Survey. 27 June 1929.