The United States Geological Survey recorded a Magnitude 6.9 Earthquake at a depth of 9.6 km roughly 50 km to the south of Elephant Island in the South Shetland Islands, slightly after 8.35 pm local time (slightly after 11.35 pm GMT) on Saturday 23 January 2021. This is a large Earthquake, and potentially very dangerous in a less remote area; in this case there are no reports of any damage or injuries associated with the event, although people have reported feeling it at the Chilean Great Wall Station on King George Island.
The South Shetland Islands lie on the boundary between the Antarctic Plate and the South Shetland Plate, a small tectonic plate more-or-less surrounded by the Antarctic Plate, and being subducted beneath it from the southeast in the South Shetland Trench, with the majority of the South Shetlands forming an island arc above the subduction zone. Elephant and Clarence Islands lie away from the rest of the South Shetland Islands, on the boundary between the South Shetland Plate and the Scotia Plate, though they probably share a common origin with the other islands. The margin between the South Shetland Plate and the Scotia Plate is a Transform Margin, where the two plates move past one-another, the Scotia Plate moving east with regard to the South Sandwich Island Plate. This is not a smooth process, the plates often sticking, leading to a pressure build-up, then an earthquake (or series of earthquakes) as the rocks give way and the pressure is released.
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